Author: "Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA))" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA))"' showing total 893 results

Start Over Author "Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA))"

893 results on '"Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA))"'

1. Optimized Coordination of Uranyl in Engineered Calmodulin Site 1 Provides a Subnanomolar Affinity for Uranyl and a Strong Uranyl versus Calcium Selectivity

Author: Romain Pardoux, Sandrine Sauge-Merle, Nicolas Bremond, Maria Rosa Beccia, David Lemaire, Christine Battesti, Pascale Delangle, Pier Lorenzo Solari, Philippe Guilbaud, Catherine Berthomieu, Interactions Protéine Métal (IPM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Chimie de Nice (ICN), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Département Interfaces pour l'énergie, la Santé et l'Environnement (DIESE), Synchrotron SOLEIL (SOLEIL), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), and CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN))
Subjects: Inorganic Chemistry, Calmodulin, Carboxylic Acids, Uranium, Calcium, [CHIM.COOR]Chemical Sciences/Coordination chemistry, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, [SDV.TOX.TCA]Life Sciences [q-bio]/Toxicology/Toxicology and food chain, Physical and Theoretical Chemistry, Ligands, Peptides, Cyclic
Abstract: As an alpha emitter and chemical toxicant, uranium toxicity in living organisms is driven by its molecular interactions. It is therefore essential to identify main determinants of uranium affinity for proteins. Others and we showed that introducing a phosphoryl group in the coordination sphere of uranyl confers a strong affinity of proteins for uranyl. In this work, using calmodulin site 1 as a template, we modulate the structural organization of a metal-binding loop comprising carboxylate and/or carbonyl ligands and reach affinities for uranyl comparable to that provided by introducing a strong phosphoryl ligand. Shortening the metal binding loop of calmodulin site 1 from 12 to 10 amino acids in CaMΔ increases the uranyl-binding affinity by about 2 orders of magnitude to log
Published: 2022

2. SHORT-ROOT stabilizes PHOSPHATE1 to regulate phosphate allocation in Arabidopsis

Author: Xinlong Xiao, Jieqiong Zhang, Viswanathan Satheesh, Fanxiao Meng, Wenlan Gao, Jinsong Dong, Zai Zheng, Guo-Yong An, Laurent Nussaume, Dong Liu, Mingguang Lei, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Plant Environmental Physiology and Stress Signaling (PEPSS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Biologie végétale et microbiologie environnementale - UMR7265 (BVME)
Subjects: Arabidopsis Proteins, plants, pho1, nutrient, fungi, Arabidopsis, food and beverages, Plant Science, Plant Roots, Organophosphates, Phosphates, gene-expression identification, Low-pi stress, Gene Expression Regulation, Plant, Mutation, homeostasis, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, starvation responses, Plant Shoots, Transcription Factors, degradation
Abstract: International audience; The coordinated distribution of inorganic phosphate (Pi) between roots and shoots is an important process that plants use to maintain Pi homeostasis. SHORT-ROOT (SHR) is well characterized for its function in root radial patterning. Here we demonstrate a role of SHR in controlling Pi allocation from root to shoot by regulating PHOSPHATE1 in the root differentiation zone. We recovered a weak mutant allele of SHR in Arabidopsis that accumulates much less Pi in the shoot and shows a constitutive Pi starvation response under Pi-sufficient conditions. In addition, Pi starvation suppresses SHR protein accumulation and releases its inhibition on the HD-ZIP III transcription factor PHB. PHB accumulates and directly binds the promoter of PHOSPHATE2 to upregulate its transcription, resulting in PHOSPHATE1 degradation in the xylem-pole pericycle cells. Our findings reveal a previously unrecognized mechanism of how plants regulate Pi translocation from roots to shoots.Plants confronted with nutrient deficiency allocate more resources to roots to maximize nutrient acquisition and growth. This study uncovers how plants repress phosphate uploading to curtail the long-distance transportation of phosphate to shoots.
Published: 2022

3. Uranium-tolerant soil bacteria protect Arabidopsis thaliana seedling growth in a uranium pollution context

Author: Adrien, Galeone, Devime, Fabienne, Chapon, Virginie, Merroun, Mohamed, Alban, Claude, Ravanel, Stéphane, Bourguignon, Jacques, Plantes, Stress & Métaux (MetalStress), Physiologie cellulaire et végétale (LPCV), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Biologie végétale et microbiologie environnementale - UMR7265 (BVME), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Interactions Protéine Métal (IPM), University of Granada, ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017), and European Project: 900009,RadoNorm project
Subjects: Accumulation, [SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Plant-bacteria interactions, Uranyl nitrate Microbacterium sp. ViU2A Stenotrophomonas bentonitica Accumulation Plant-bacteria interactions, Microbacterium sp. ViU2A, Stenotrophomonas bentonitica, Uranyl nitrate
Abstract: We investigated the impact of uranium (U) on Arabidopsis thaliana seed germination and on the early stages of seedling development. Using an in vitro device, we demonstrated that uranyl ion had a very low impact on Arabidopsis seed germination but had a drastic effect on the development of Arabidopsis seedlings. We showed that the two soil bacterial strains Microbacterium sp. ViU2A and Stenotrophomonas bentonitica BII-R7, which are able to tolerate high concentrations of U, strongly reduced the toxic effects of the metal on the seedling development. This protective effect is specific to these soil bacteria, as E. coli was not able to protect seedlings. The analysis of the distribution of U between Arabidopsis seedlings and soil bacteria showed that the protective effect of the bacteria was due to their ability to sequester U either by biosorption at the level of the cell surface and/or by intracellular or extracellular biomineralization.This study reveals that these bacteria are very good candidates for use in phytoremediation strategies in the case of phytostabilisation of U-polluted soils. They would be also useful to limit the contamination of the food chain by U because they would limit the entry of this toxic element in crop plants.
Published: 2023

4. Guanosine tetraphosphate ( <scp>ppGpp</scp> ) accumulation inhibits chloroplast gene expression and promotes super grana formation in the moss Physcomitrium ( Physcomitrella ) patens

Author: Seddik Harchouni, Samantha England, Julien Vieu, Shanna Romand, Aicha Aouane, Sylvie Citerne, Bertrand Legeret, Jean Alric, Yonghua Li‐Beisson, Benoît Menand, Benjamin Field, Luminy Génétique et Biophysique des Plantes (LGBP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS), Institut Jean-Pierre Bourgin (IJPB), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Environnement, Bioénergie, Microalgues et Plantes (EBMP), CEA Irtelis PhD fellowship, APEX grant from the Provence-Alpes Cote d'Azur Region, ANR-15-CE05-0021,SIGNAUXBIONRJ,Manipulation des voies de signalisation de l'énergie afin d'améliorer la production de .lipides chez les eucaryotes photosynthétiques(2015), ANR-17-EURE-0007,SPS-GSR,Ecole Universitaire de Recherche de Sciences des Plantes de Paris-Saclay(2017), and ANR-10-INBS-0004,France-BioImaging,Développment d'une infrastructure française distribuée coordonnée(2010)
Subjects: Chloroplasts, photosynthesis, thylakoid, Physiology, growth, fungi, Arabidopsis, Guanosine Pentaphosphate, food and beverages, Guanosine Tetraphosphate, Plant Science, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, equipment and supplies, Thylakoids, Bryopsida, moss, Genes, Chloroplast, Physcomitrium patens, bacteria, guanosine tetraphosphate (ppGpp), heterocyclic compounds, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology
Abstract: The nucleotides guanosine tetraphosphate and pentaphosphate (or (p)ppGpp) are implicated in the regulation of chloroplast function in plants. (p)ppGpp signalling is best understood in the model vascular plant Arabidopsis thaliana in which it acts to regulate plastid gene expression to influence photosynthesis, plant development and immunity. However, little information is known about the conservation or diversity of (p)ppGpp signalling in other land plants. We studied the function of ppGpp in the moss Physcomitrium (previously Physcomitrella) patens using an inducible system for triggering ppGpp accumulation. We used this approach to investigate the effects of ppGpp on chloroplast function, photosynthesis and growth. We demonstrate that ppGpp accumulation causes a dramatic drop in photosynthetic capacity by inhibiting chloroplast gene expression. This was accompanied by the unexpected reorganisation of the thylakoid system into super grana. Surprisingly, these changes did not affect gametophore growth, suggesting that bryophytes and vascular plants may have different tolerances to defects in photosynthesis. Our findings point to the existence of both highly conserved and more specific targets of (p)ppGpp signalling in the land plants that may reflect different growth strategies.
Published: 2022

5. Development of an Efficient FRET-Based Ratiometric Uranium Biosensor

Author: Sandrine Sauge-Merle, Morgane Recuerda, Maria Rosa Beccia, David Lemaire, Rym Cherif, Nicolas Bremond, Fabienne Merola, Yasmina Bousmah, Catherine Berthomieu, Interactions Protéine Métal (IPM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Programme Transversal de Toxicologie du CEA et NEEDS Ressources du CNRS
Subjects: calmodulin, metal-binding, [SDV]Life Sciences [q-bio], Clinical Biochemistry, selectivity, Biomedical Engineering, protein engineering, General Medicine, sensitivity, Analytical Chemistry, genetically encoded biosensor, uranium, FRET, sensing, Instrumentation, Engineering (miscellaneous), Biotechnology
Abstract: International audience; The dispersion of uranium in the environment can pose a problem for the health of humans and other living organisms. It is therefore important to monitor the bioavailable and hence toxic fraction of uranium in the environment, but no efficient measurement methods exist for this. Our study aims to fill this gap by developing a genetically encoded FRET-based ratiometric uranium biosensor. This biosensor was constructed by grafting two fluorescent proteins to both ends of calmodulin, a protein that binds four calcium ions. By modifying the metal-binding sites and the fluorescent proteins, several versions of the biosensor were generated and characterized in vitro. The best combination results in a biosensor that is affine and selective for uranium compared to metals such as calcium or other environmental compounds (sodium, magnesium, chlorine). It has a good dynamic range and should be robust to environmental conditions. In addition, its detection limit is below the uranium limit concentration in drinking water defined by the World Health Organization. This genetically encoded biosensor is a promising tool to develop a uranium whole-cell biosensor. This would make it possible to monitor the bioavailable fraction of uranium in the environment, even in calcium-rich waters.; La dispersion de l'uranium dans l'environnement peut poser un problème pour la santé de l'homme et des autres organismes vivants. Il est donc important de surveiller la fraction biodisponible, et donc toxique, de l'uranium dans l'environnement, mais il n'existe pas de méthodes de mesure efficaces pour cela. Notre étude vise à combler cette lacune en développant un biosenseur ratiométrique d'uranium basé sur le FRET et codé génétiquement. Ce biosenseur a été construit en greffant deux protéines fluorescentes aux deux extrémités de la calmoduline, une protéine qui lie quatre ions calcium. En modifiant les sites de fixation des métaux et les protéines fluorescentes, plusieurs versions du biosenseur ont été générées et caractérisées in vitro. La meilleure combinaison permet d'obtenir un biosenseur affin et sélectif pour l'uranium par rapport à des métaux tels que le calcium ou d'autres composés environnementaux (sodium, magnésium, chlore). Il possède une bonne plage dynamique et devrait être robuste aux conditions environnementales. En outre, sa limite de détection est inférieure à la concentration limite d'uranium dans l'eau potable définie par l'Organisation Mondiale de la Santé. Ce biosenseur codé génétiquement est un outil prometteur pour développer un biosenseur à cellules entières d'uranium. Cela permettrait de surveiller la fraction biodisponible de l'uranium dans l'environnement, même dans les eaux riches en calcium.
Published: 2023
Full Text: View/download PDF

6. Investigation of the Plutonium(IV) Interactions with Two Variants of the EF-Hand Ca-Binding Site I of Calmodulin

Author: Loïc Daronnat, Vanessa Holfeltz, Nathalie Boubals, Thomas Dumas, Philippe Guilbaud, Diego Moreno Martinez, Philippe Moisy, Sandrine Sauge-Merle, David Lemaire, Pier Lorenzo Solari, Laurence Berthon, Catherine Berthomieu, Interactions Protéine Métal (IPM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Inorganic Chemistry, [SDV]Life Sciences [q-bio], Physical and Theoretical Chemistry
Abstract: International audience; Due to its presence in the nuclear industry and its strong radiotoxicity, plutonium is an actinide of major interest in the event of internal contamination. To improve the understanding of its mechanisms of transport and accumulation in the body, the complexation of Pu(IV) to the most common protein calcium-binding motif found in cells, the EF-hand motif of calmodulin, was investigated. Visible and X-ray absorption spectroscopies (XAS) in solution made it possible to investigate the speciation of plutonium at physiological pH (pH 7.4) and pH 6 in two variants of the calmodulin Ca-binding site I and using Pu(IV) in different media: carbonate, chloride, or nitrate solutions. Three different species of Pu were identified in the samples, with formation of 1:1 Pu(IV):calmodulin peptide complexes, Pu(IV) reduction, and formation of peptide-mediated Pu(IV) hexanuclear cluster.
Published: 2023

7. Post-translational regulation of photosynthetic activity via the TOR kinase in plants

Author: Stefano D’Alessandro, Florent Velay, Régine Lebrun, Marwa Mehrez, Shanna Romand, Rim Saadouni, Céline Forzani, Sylvie Citerne, Marie-Hélène Montané, Christophe Robaglia, Benoît Menand, Christian Meyer, Ben Field, Università degli Studi di Padova = University of Padua (Unipd), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Biologie végétale et microbiologie environnementale - UMR7265 (BVME), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Luminy Génétique et Biophysique des Plantes (LGBP), Institut de Microbiologie de la Méditerranée (IMM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), University of Tunis El Manar, Institut Jean-Pierre Bourgin (IJPB), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), ANR-17-CE13-0005,G4PLAST,Mecanismes d'acclimation aux stress par la voie conservée de signalisation du (p)ppGpp dans le chloroplaste.(2017), and ANR-22-CE20-0033,TARGET_G4P,Identification des cibles et de la régulation de la voie ppGpp chez les plantes.(2022)
Subjects: ppGpp, chloroplast, [SDV]Life Sciences [q-bio], [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, TOR, Photosynthesis
Abstract: Chloroplasts are the powerhouse of the plant cell, yet they are resource-intensive and will cause photooxidative damage if their activity overshoots the demands of growth. The adjustment of chloroplast activity to match growth is therefore vital for stress acclimation. Here we identify a novel post-translational mechanism linking the conserved eukaryotic TOR kinase that promotes growth and the guanosine tetraphosphate (ppGpp) signaling pathway of prokaryotic origin that regulates chloroplast activity, and photosynthesis in particular. We show that RelA SpoT Homologue 3 (RSH3), a nuclear-encoded chloroplastic enzyme responsible for ppGpp biosynthesis, interacts directly with the TOR complex via a plant-specific N-terminal region (NTR) which is hyper-phosphorylated in a TOR-dependent manner. Downregulation of TOR activity reduces NTR phosphorylation, enhances ppGpp synthesis by RSH3, and causes a ppGpp-dependent decrease in photosynthetic capacity. Altogether we demonstrate that the TOR-RSH3 signaling axis is a novel and direct post-translational mechanism that allows chloroplast activity to be matched with plant growth, setting a new precedent for the regulation of organellar function by TOR.One sentence summaryThe TOR kinase post-translationally controls guanosine tetraphosphate signaling to regulate plant photosynthetic activity.
Published: 2023

8. Epitaxial van der Waals heterostructures of Cr 2 Te 3 on two-dimensional materials

Author: Guillet, Quentin, Vojáček, Libor, Dosenovic, Djordje, Ibrahim, Fatima, Boukari, Hervé, Li, Jing, Choueikani, Fadi, Ohresser, Philippe, Ouerghi, Abdelkarim, Mesple, Florie, Renard, Vincent, Jacquot, Jean-François, Jalabert, Denis, Okuno, Hanako, Chshiev, Mairbek, Vergnaud, Céline, Bonell, Frédéric, Marty, Alain, Jamet, Matthieu, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Nanophysique et Semiconducteurs (NEEL - NPSC), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Transport Electronique Quantique et Supraconductivité (LaTEQS), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Institut Universitaire de France (IUF), and Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)
Subjects: [PHYS]Physics [physics], [SPI]Engineering Sciences [physics]
Abstract: International audience; Abstract The recent discovery of superconductivity in paramagnetic UTe 2 turns spotlight on a serious candidate for spin-triplet state. To draw a complete picture of the superconducting state in UTe 2 precise knowledge of the electronic properties of the 5 f states of Uranium is missing. We report on x-ray absorption and magnetic circular dichroism experiments performed at the U M 4,5 edges at 2.7 K. At ambient pressure the 5 f electron count is found to be in-between 2.6 and 2.8. Partial delocalization of the 5 f electrons is further confirmed by the reduced value of the U orbital to spin magnetic moment ratio. The 5 f count is reduced by as large as 7 percent at the transition to a magnetically ordered state at P c ≈ 1.5 GPa. At pressures above 4 GPa, the 5 f count increases back towards U 3+ in the tetragonal phase. The observed “valence instabilities” and their interplay with magnetism seem to be important ingredients to understand the electronic structure in UTe 2 in different phases.
Published: 2023

9. Culturing the desert microbiota

Author: Zakia Selmani, Eleonore Attard, Béatrice Lauga, Mohamed Barakat, Philippe Ortet, Joris Tulumello, Wafa Achouak, Yahia Kaci, Thierry Heulin, Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Microbiology (medical), culturability, [SDE]Environmental Sciences, microbiota, [CHIM]Chemical Sciences, Microbiology, desert, Sahara, diversity
Abstract: Over the last 30 years, the description of microbial diversity has been mainly based on culture-independent approaches (metabarcoding and metagenomics) allowing an in-depth analysis of microbial diversity that no other approach allows. Bearing in mind that culture-dependent approaches cannot replace culture-independent approaches, we have improved an original method for isolating strains consisting of “culturing” grains of sand directly on Petri dishes (grain-by-grain method). This method allowed to cultivate up to 10% of the bacteria counted on the surface of grains of the three sites studied in the Great Western Erg in Algeria (Timoudi, Béni Abbès, and Taghit), knowing that on average about 10 bacterial cells colonize each grain. The diversity of culturable bacteria (collection of 290 strains) predicted by 16S rRNA gene sequencing revealed that Arthrobacter subterraneus, Arthrobacter tecti, Pseudarthrobacter phenanthrenivorans, Pseudarthrobacter psychrotolerans, and Massilia agri are the dominant species. The comparison of the culture-dependent and -independent (16S rRNA gene metabarcoding) approaches at the Timoudi site revealed 18 bacterial genera common to both approaches with a relative overestimation of the genera Arthrobacter/Pseudarthrobacter and Kocuria, and a relative underestimation of the genera Blastococcus and Domibacillus by the bacterial culturing approach. The bacterial isolates will allow further study on the mechanisms of tolerance to desiccation, especially in Pseudomonadota (Proteobacteria).
Published: 2023

10. Cyclic and pseudo-cyclic electron pathways play antagonistic roles during nitrogen deficiency in Chlamydomonas reinhardtii

Author: Ousmane Dao, Adrien Burlacot, Marie Huleux, Pascaline Auroy, Gilles Peltier, Yonghua Li-Beisson, Environnement, Bioénergie, Microalgues et Plantes (EBMP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE)
Subjects: [SDV]Life Sciences [q-bio]
Abstract: Nitrogen (N) deficiency is a frequently encountered situation that constrains global biomass productivity. In response to N deficiency, cell division stops and photosynthetic electron transfer are downregulated, while carbon storage is enhanced. However, the molecular mechanism downregulating photosynthesis during N deficiency and its relationship with carbon storage are not fully understood. The Proton Gradient Regulator-like 1 (PGRL1)-involved in cyclic electron flow (CEF) and Flavodiiron proteins involved in pseudo-(CEF) are major players in the acclimation of photosynthesis. To determine the role of PGRL1 or FLV in photosynthesis under N deficiency, we measured photosynthetic electron transfer, oxygen gas exchange and carbon storage in the knockout of Chlamydomonaspgrl1 and flvBmutants. Under N deficiency,pgrl1maintains higher net photosynthesis and O2photoreduction rates, whileflvBshows similar responses compared to control strains. The amount of cytochromeb6fwas maintained at a higher level inpgrl1. The photosynthetic activity ofpgrl1 flvBdouble mutants decreases in response to N deficiency similar to the control strains. Furthermore, the triacylglycerol content ofpgrl1was twice higher than the controls under N deficiency. Taken together, our results suggest that in the absence of PGRL1, FLV-mediated O2photoreduction through PCEF maintains net photosynthesis at a high level, resulting in increased triacylglycerol biosynthesis. This study reveals that PGRL1 and FLV play antagonistic roles during N deficiency. It further illustrates how nutrient status can affect the regulation of photosynthetic energy production in relation to carbon storage and provides new strategies for improving lipid productivity in algae.Significance statementNitrogen (N) deficiency, an often-encountered phenomenon in nature, triggers growth arrest and massive lipid accumulation in microalgae. The downregulation of photosynthesis is necessary to ensure cell viability. We demonstrate that a well-conserved protein in chlorophytes, the Proton Gradient Regulator-like 1 (PGRL1) is a key (down) regulator of photosynthesis. In its absence, cells exhibited sustained photosynthesis and over-accumulated lipids thanks to the Flavodiiron (FLV) protein. We propose that both PGRL1 and FLV, by having antagonistic roles in N deficiency, manage the redox landscape, carbon storage and biomass production. Our work revolves around the current paradigm of photosynthesis regulation during N deficiency and provides a new framework for improving lipid accumulation in microalgae for biotechnological purposes.
Published: 2023

11. Tritium: Its relevance, sources and impacts on non-human biota

Author: Maria Florencia Ferreira, Andrew Turner, Emily L. Vernon, Christian Grisolia, Laurence Lebaron-Jacobs, Veronique Malard, Awadhesh N. Jha, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Interactions Protéine Métal (IPM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: nuclear energy, Environmental Engineering, Toxicity, Radiation dose, [SDE]Environmental Sciences, Environmental Chemistry, Environment, Tritiated Water (HTO), Pollution, Waste Management and Disposal, Tritrium, Risk assessment
Abstract: Tritium (3H) is a radioactive isotope of hydrogen that is abundantly released from nuclear industries. It is extremely mobile in the environment and in all biological systems, representing an increasing concern for the health of both humans and non-human biota (NHB). The present review examines the sources and characteristics of tritium in the environment, and evaluates available information pertaining to its biological effects at different levels of biological organisation in NHB. Despite an increasing number of publications in the tritiumradiobiology field, there exists a significant disparity between data available for the different taxonomic groups and species, and observations are heavily biased towards marine bivalves, fish and mammals (rodents). Further limitations relate to the scarcity of information in the field relative to the laboratory, and lack of studies that employ forms of tritiumother than tritiated water (HTO). Within these constraints, different responses toHTOexposure, frommolecular to behavioural, have been reported during early life stages, but the potential transgenerational effects are unclear. The application of rapidly developing “omics” techniques could help to fill these knowledge gaps and further elucidate the relationships between molecular and organismal level responses through the development of radiation specific adverse outcome pathways (AOPs). The use of a greater diversity of keystone species and exposures to multiple stressors, elucidating other novel effects (e.g., by-stander, germ-line, transgenerational and epigenetic effects) offers opportunities to improve environmental risk assessments for the radionuclide. These could be combined with artificial intelligence (AI) including machine learning (ML) and ecosystem-based approaches.
Published: 2023

12. Epitaxial van der Waals heterostructures of Cr2Te3 on 2D materials

Author: Guillet, Quentin, Vojacek, Libor, Dosenovic, Djordje, Ibrahim, Fatima, Boukari, Herve, Li, Jing, Choueikani, Fadi, Ohresser, Philippe, Ouerghi, Abdelkarim, Mesple, Florie, Renard, Vincent, Jacquot, Jean-Francois, Jalabert, Denis, Okuno, Hanako, Chshiev, Mairbek, Vergnaud, Celine, Bonell, Frederic, Marty, Alain, Jamet, Matthieu, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Nanophysique et Semiconducteurs (NEEL - NPSC), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Transport Electronique Quantique et Supraconductivité (LaTEQS), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), ANR-18-CE24-0007,MAGICVALLEY,Polarisation de vallée induite par couplage d'échange magnétique dans les matériaux 2D à grande échelle(2018), ANR-20-CE24-0015,ELMAX,Contrôle électrique de l'aimantation dans les hétérostructures van der Waals épitaxiées(2020), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), ANR-21-ESRE-0025,2D-MAG,Two-dimensional magnetic materials(2021), European Project: 800945,NUMERICS, and European Project: 881603,H2020,H2020-SGA-FET-GRAPHENE-2019, GrapheneCore3(2020)
Subjects: [PHYS]Physics [physics], Condensed Matter - Materials Science, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences
Abstract: Achieving large-scale growth of two-dimensional (2D) ferromagnetic materials with high Curie temperature (TC) and perpendicular magnetic anisotropy (PMA) is highly desirable for the development of ultra-compact magnetic sensors and magnetic memories. In this context, van der Waals (vdW) Cr2Te3 appears as a promising candidate. Bulk Cr2Te3 exhibits strong PMA and a TC of 180 K. Moreover, both PMA and TC might be adjusted in ultrathin films by engineering composition, strain, or applying an electric field. In this work, we demonstrate the molecular beam epitaxy (MBE) growth of vdW heterostructures of five-monolayer quasi-freestanding Cr2Te3 on three classes of 2D materials: graphene (semimetal), WSe2 (semiconductor) and Bi2Te3 (topological insulator). By combining structural and chemical analysis down to the atomic level with ab initio calculations, we confirm the single crystalline character of Cr2Te3 films on the 2D materials with sharp vdW interfaces. They all exhibit PMA and TC close to the bulk Cr2Te3 value of 180 K. Ab initio calculations confirm this PMA and show how its strength depends on strain. Finally, Hall measurements reveal a strong anomalous Hall effect, which changes sign at a given temperature. We theoretically explain this effect by a sign change of the Berry phase close to the Fermi level. This transition temperature depends on the 2D material in proximity, notably as a consequence of charge transfer. MBE-grown Cr2Te3/2D material bilayers constitute model systems for the further development of spintronic devices combining PMA, large spin-orbit coupling and sharp vdW interface., Comment: 18 pages, 13 figures and Supplemental Material
Published: 2023

13. Insights into the function of the chloroplastic ribosome-associated GTPase HflX inArabidopsis thaliana

Author: Marwa Mehrez, Cécile Lecampion, Hang Ke, Faten Gorsane, Ben Field, Luminy Génétique et Biophysique des Plantes (LGBP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of Tunis El Manar, Université de Carthage - University of Carthage, ANR-22-CE20-0033,TARGET_G4P,Identification des cibles et de la régulation de la voie ppGpp chez les plantes.(2022), and ANR-17-CE13-0005,G4PLAST,Mecanismes d'acclimation aux stress par la voie conservée de signalisation du (p)ppGpp dans le chloroplaste.(2017)
Subjects: [SDV]Life Sciences [q-bio]
Abstract: Ribosome-associated GTPases are conserved enzymes that participate in ribosome biogenesis and ribosome function. In bacteria, recent studies have identified HflX as a ribosome-associated GTPase that is involved in both ribosome biogenesis and recycling under stress conditions. Plants possess a chloroplastic HflX homolog, but its function remains unknown. Here, we characterised the role of HflX in the plantArabidopsis thaliana. Our findings demonstrate that HflX does not have a detectable role in plant growth and development, nor does it play a distinct role in acclimation to several different stresses, including heat, manganese, cold, and salt stress. However, we found that HflX is required for plant resistance to chloroplast translational stress mediated by the antibiotic lincomycin. Our results suggest that HflX is a chloroplast ribosome-associated protein that may play a role in the surveillance of translation. These findings provide new insight into the function of HflX as a ribosome-associated GTPase in plants and highlight the importance of investigating conserved proteins in different organisms to gain a comprehensive understanding of their biological roles.
Published: 2023

14. Ultrafast Excitation Energy Transfer Dynamics in the LHCII–CP29–CP24 Subdomain of Plant Photosystem II

Author: Thanh Nhut Do, Hoang Long Nguyen, Parveen Akhtar, Kai Zhong, Thomas L. C. Jansen, Jasper Knoester, Stefano Caffarri, Petar H. Lambrev, Howe-Siang Tan, School of Physical and Mathematical Sciences, Theory of Condensed Matter, Zernike Institute for Advanced Materials, Luminy Génétique et Biophysique des Plantes (LGBP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, 01.03. Fizikai tudományok, Energy Transfer, Chemistry [Science], Electronic Spectrum, Plant Photosystem, Light-Harvesting Protein Complexes, Photosystem II Protein Complex, General Materials Science, Plants, Physical and Theoretical Chemistry, Thylakoids, ComputingMilieux_MISCELLANEOUS
Abstract: We measure the two-dimensional electronic spectra of the LHCII(M)-CP29-CP24 complex in photosystem II (PSII) and provide the first study of the ultrafast excitation energy transfer (EET) processes of an asymmetric and native light-harvesting assembly of the antenna of PSII. With comparisons to LHCII, we observe faster energy equilibrations in the intermediate levels of the LHCII(M)-CP29-CP24 complex at 662 and 670 nm. Notably, the putative "bottleneck" states in LHCII exhibit faster effective dynamics in the LHCII(M)-CP24-CP29 complex, with the average lifetime shortening from 2.5 ps in LHCII to 1.2 ps in the bigger assembly. The observations are supported by high-level structure-based calculations, and the accelerated dynamics can be attributed to the structural change of LHCII(M) in the bigger complex. This study shows that the biological functioning structures of the complexes are important to understand the overall EET dynamics of the PSII supercomplex. Ministry of Education (MOE) This work was supported by grants from the Singapore Ministry of Education Academic Research Fund (Tier 1 RG2/19 and Tier 1 RG14/20 to Howe-Siang Tan), the National Research, Development and Innovations Office, Hungary (NKFIH 2018- 1.2.1-NKP-2018-000009 to Petar H. Lambrev), and the Eötvös Loránd Research Network (KÖ -36/2021 to Petar H. Lambrev).
Published: 2022

15. The Chlamydomonas transcription factor MYB1 mediates lipid accumulation under nitrogen depletion

Author: Bae Young Choi, Donghwan Shim, Fantao Kong, Pascaline Auroy, Yuree Lee, Yonghua Li‐Beisson, Youngsook Lee, Yasuyo Yamaoka, Environnement, Bioénergie, Microalgues et Plantes (EBMP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Nitrogen, Physiology, [SDV]Life Sciences [q-bio], Chlamydomonas, Fatty Acids, Plant Science, Lipid Metabolism, ComputingMilieux_MISCELLANEOUS, Chlamydomonas reinhardtii, Triglycerides, Transcription Factors
Abstract: Microalgae accumulate high levels of oil under stress, but the underlying biosynthetic pathways are not fully understood. We sought to identify key regulators of lipid metabolism under stress conditions. We found that the Chlamydomonas reinhardtii gene encoding the MYB-type transcription factor MYB1 is highly induced under stress conditions. Two myb1 mutants accumulated less total fatty acids and storage lipids than their parental strain upon nitrogen (N) depletion. Transcriptome analysis revealed that genes involved in lipid metabolism are highly enriched in the wild-type but not in the myb1-1 mutant after 4 h of N depletion. Among these genes were several involved in the transport of fatty acids from the chloroplast to the endoplasmic reticulum (ER): acyl-ACP thioesterase (FAT1), Fatty Acid EXporters (FAX1, FAX2), and long-chain acyl-CoA synthetase1 (LACS1). Furthermore, overexpression of FAT1 in the chloroplast increased lipid production. These results suggest that, upon N depletion, MYB1 promotes lipid accumulation by facilitating fatty acid transport from the chloroplast to the ER. This study identifies MYB1 as an important positive regulator of lipid accumulation in C. reinhardtii upon N depletion, adding another player to the established regulators of this process, including NITROGEN RESPONSE REGULATOR 1 (NRR1) and TRIACYLGLYCEROL ACCUMULATION REGULATOR 1 (TAR1).
Published: 2022

16. A manipulation of carotenoid metabolism influence biomass partitioning and fitness in tomato

Author: Jianing Mi, Jose G. Vallarino, Ivan Petřík, Ondřej Novák, Sandra M. Correa, Monika Chodasiewicz, Michel Havaux, Manuel Rodriguez-Concepcion, Salim Al-Babili, Alisdair R. Fernie, Aleksandra Skirycz, Juan C. Moreno, King Abdullah University of Science and Technology (KAUST), Max-Planck-Institut für Molekulare Pflanzenphysiologie (MPI-MP), Max-Planck-Gesellschaft, Laboratory of Growth Regulators [Univ Palacký] (LGR), Faculty of Science [Univ Palacký], Palacky University Olomouc-Palacky University Olomouc-Institute of Experimental Botany of the Czech Academy of Sciences (IEB / CAS), Czech Academy of Sciences [Prague] (CAS)-Czech Academy of Sciences [Prague] (CAS), Plant Environmental Physiology and Stress Signaling (PEPSS), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), and Instituto de Biología Molecular y Celular de Plantas
Subjects: Abiotic stress tolerance, [SDV]Life Sciences [q-bio], fungi, Biomass and yield, food and beverages, Bioengineering, Metabolites and lipids, Carotenoids, Applied Microbiology and Biotechnology, Biosynthetic Pathways, Solanum lycopersicum, Stress, Physiological, Apocarotenoids, Metabolic engineering, Phytohormones, Biomass, Biotechnology
Abstract: Improving yield, nutritional value and tolerance to abiotic stress are major targets of current breeding and biotechnological approaches that aim at increasing crop production and ensuring food security. Metabolic engineering of carotenoids, the precursor of vitamin-A and plant hormones that regulate plant growth and response to adverse growth conditions, has been mainly focusing on provitamin A biofortification or the production of high-value carotenoids. Here, we show that the introduction of a single gene of the carotenoid biosynthetic pathway in different tomato cultivars induced profound metabolic alterations in carotenoid, apocarotenoid and phytohormones pathways. Alterations in isoprenoid- (abscisic acid, gibberellins, cytokinins) and non-isoprenoid (auxin and jasmonic acid) derived hormones together with enhanced xanthophyll content influenced biomass partitioning and abiotic stress tolerance (high light, salt, and drought), and it caused an up to 77% fruit yield increase and enhanced fruit's provitamin A content. In addition, metabolic and hormonal changes led to accumulation of key primary metabolites (e.g. osmoprotectants and antiaging agents) contributing with enhanced abiotic stress tolerance and fruit shelf life. Our findings pave the way for developing a new generation of crops that combine high productivity and increased nutritional value with the capability to cope with climate change-related environmental challenges.
Published: 2022

17. Stimulation par le rayonnement lumineux de la production de pigments bactériens pour la conception d’OLEDs

Author: Lajoie, Barbora, Andriantsiferana, Caroline, Loubière, Karine, El Garah, Fatima, Bouajila, Jaloul, Zissis, Georges, BUSO, DAVID, Blanchard, Laurence, de Groot, Arjan, Alaoui-Sossé, Badr, Attia, Rym, Laboratoire de Génie Chimique (LGC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Service Central d'Analyse (SCA), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Lumière et Matière (LAPLACE-LM), LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Grenoble Alpes (UGA), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Pathologies et épithéliums : prévention, innovation, traitements, évaluation (UR 4267) (PEPITE), Université de Franche-Comté (UFC), Institut National des Sciences Appliquées et de Technologie [Tunis] (INSAT), CNRS AAP 'Adaptation' Projet SUNRAY, and CNRS
Subjects: [SDV.BIO]Life Sciences [q-bio]/Biotechnology, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology
Abstract: International audience
Published: 2023

18. Spectroscopic insights into the mechanism of anammox hydrazine synthase

Author: Wouter Versantvoort, Rainer Hienerwadel, Christina Ferousi, Pieter van der Velden, Catherine Berthomieu, Laura van Niftrik, Frauke Baymann, Radboud University [Nijmegen], Luminy Génétique et Biophysique des Plantes (LGBP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Interactions Protéine Métal (IPM), Bioénergétique et Ingénierie des Protéines (BIP ), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, [SDV]Life Sciences [q-bio], [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM]
Abstract: Anaerobic ammonium oxidizing bacteria make a living oxidizing ammonium with nitrite as electron acceptor, intermediates nitric oxide and hydrazine, and end product dinitrogen gas. Hydrazine is a biologically unique free intermediate in this metabolism, and is produced by the enzyme hydrazine synthase. Crystallization of ‘CandidatusKuenenia stuttgartiensis’ hydrazine synthase allowed for an initial hypothesis of its reaction mechanism. In this hypothesis, nitric oxide is first reduced to hydroxylamine after which hydroxylamine is condensed with ammonium to form hydrazine. Hydrazine synthase is a tetraheme cytochromec, containing two proposed active site hemes (γI & αI) in the γ- and α-subunit, respectively, connected by an intra-enzymatic tunnel. Here we combined the data from electrochemistry-induced Fourier transform infrared (FTIR) spectroscopy, EPR and optical spectroscopy to shed light on the redox properties and protein dynamics of hydrazine synthase in the context of its reaction mechanism. Redox titrations revealed two low potential low spin hemes with midpoint potentials of ∼-360 mV and ∼-310 mV for heme αII and γII, respectively. Heme γI showed redox transitions in the range of 0 mV, consisting of both low spin and high spin characteristics in optical and EPR spectroscopy. Electrochemistry-induced FTIR spectroscopy indicated an aspartic acid ligating a OH-/H2O at the heme γI axial site as a possible candidate for involvement in this mixed spin characteristic. Furthermore, EPR spectroscopy confirmed the ability of heme γI to bind NO in the reduced state. Heme αI exhibited a rhombic high spin signal, in line with its ligation by a proximal tyrosine observed in the crystal structure. Redox titrations down to −610 mV nor addition of dithionite resulted in the reduction of heme αI, indicating a very low midpoint potential for this heme.In vivochemistry at this heme αI, the candidate for the comproportionation of hydroxylamine and ammonium, is thus likely to be initiated solely on the oxidized heme, in contrast to previously reported DFT calculations. The reduction potentials of the γ-subunit hemes were in line with the proposed electron transfer of heme γII to heme γI for the reduction of NO to hydroxylamine (E0’ = − 30 mV).
Published: 2023

19. Targeted gene deletion with Sp Cas9 and multiple guide RNAs in Arabidopsis thaliana : four are better than two

Author: Jana Ordon, Niklas Kiel, Dieter Becker, Carola Kretschmer, Paul Schulze-Lefert, Johannes Stuttmann, Max Planck Institute for Plant Breeding Research (MPIPZ), Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], Martin-Luther-University Halle-Wittenberg, Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Julius Kühn-Institut (JKI)
Subjects: [SDV]Life Sciences [q-bio]
Abstract: BackgroundIn plant genome editing, RNA-guided nucleases such as Cas9 fromStreptococcus pyogenes(SpCas9) predominantly induce small insertions or deletions at target sites. This can be used for inactivation of protein-coding genes by frame shift mutations. However, in some cases, it may be advantageous to delete larger chromosomal segments. This is achieved by simultaneously inducing double strand breaks upstream and downstream of the fragment to be deleted. Experimental approaches for deletion induction have not been systematically evaluated.ResultsWe designed three pairs of guide RNAs for deletion of the ArabidopsisWRKY30locus (~2.2 kb). We tested how the combination of guide RNA pairs and co-expression of the exonuclease TREX2 affect the frequency ofwrky30deletions in editing experiments. Our data demonstrate that compared to one pair of guide RNAs, two pairs increase the frequency of chromosomal deletions. The exonuclease TREX2 enhanced mutation frequency at individual target sites and shifted the mutation profile towards larger deletions. However, TREX2 did not elevate the frequency of chromosomal deletions.ConclusionsMultiplex editing with at least two pairs of guide RNAs (four guide RNAs in total) elevates the frequency of chromosomal deletions, and thus simplifies the selection of corresponding mutants. Co-expression of the TREX2 exonuclease can be used as a general strategy to increase editing efficiency in Arabidopsis without obvious negative effects.
Published: 2023

20. Crystal-Chemical and Biological Controls of Elemental Incorporation into Magnetite Nanocrystals

Author: Matthieu Amor, J. Frederick W. Mosselmans, Ernesto Scoppola, Chenghao Li, Damien Faivre, Daniel M. Chevrier, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), DIAMOND Light source, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Microbiologie Environnementale et Moléculaire (MEM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Fondation pour la Recherche Médicale (ARF201909009123), and European Union Marie-Skłodowska Curie Action International Fellowship (MSCA-IF Project 797431: BioNanoMagnets)
Subjects: Biomineralization, Crystal Field Theory, [SDV]Life Sciences [q-bio], Lattice strain theory, General Engineering, General Physics and Astronomy, General Materials Science, Magnetotactic Bacteria, Magnetite Nanoparticles, Trace Element Partitioning
Abstract: International audience; Magnetite nanoparticles possess numerous fundamental, biomedical, and industrial applications, many of which depend on tuning the magnetic properties. This is often achieved by the incorporation of trace and minor elements into the magnetite lattice. Such incorporation was shown to depend strongly on the magnetite formation pathway (i.e., abiotic vs biological), but the mechanisms controlling element partitioning between magnetite and its surrounding precipitation solution remain to be elucidated. Here, we used a combination of theoretical modeling (lattice and crystal field theories) and experimental evidence (high-resolution inductively coupled plasma–mass spectrometry and X-ray absorption spectroscopy) to demonstrate that element incorporation into abiotic magnetite nanoparticles is controlled principally by cation size and valence. Elements from the first series of transition metals (Cr to Zn) constituted exceptions to this finding, as their incorporation appeared to be also controlled by the energy levels of their unfilled 3d orbitals, in line with crystal field mechanisms. We finally show that element incorporation into biological magnetite nanoparticles produced by magnetotactic bacteria (MTB) cannot be explained by crystal–chemical parameters alone, which points to the biological control exerted by the bacteria over the element transfer between the MTB growth medium and the intracellular environment. This screening effect generates biological magnetite with a purer chemical composition in comparison to the abiotic materials formed in a solution of similar composition. Our work establishes a theoretical framework for understanding the crystal–chemical and biological controls of trace and minor cation incorporation into magnetite, thereby providing predictive methods to tailor the composition of magnetite nanoparticles for improved control over magnetic properties.
Published: 2023

21. Tritiated steel micro-particles: computational dosimetry and prediction of radiation-induced dna damage for in vitro cell culture exposures

Author: Alice Mentana, Yordenca Lamartinière, Thierry Orsière, Véronique Malard, Mickaël Payet, Danielle Slomberg, Isabella Guardamagna, Leonardo Lonati, Cristian Grisolia, Awadhesh Jha, Laurence Lebaron-Jacobs, Jerome Rose, Andrea Ottolenghi, Giorgio Baiocco, Università degli Studi di Pavia = University of Pavia (UNIPV), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Interactions Protéine Métal (IPM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), School of Biological and Marine Sciences, Plymouth University, ANR-10-INBS-0004,France-BioImaging,Développment d'une infrastructure française distribuée coordonnée(2010), and European Project: 754586,TRANSAT
Subjects: Radiation, [SDV.TOX]Life Sciences [q-bio]/Toxicology, Biophysics, Radiology, Nuclear Medicine and imaging
Abstract: International audience; Biological effects of radioactive particles can be experimentally investigated in vitro as a function of particle concentration, specific activity and exposure time. However, a careful dosimetric analysis is needed to elucidate the role of radiation emitted by radioactive products in inducing cyto- and geno-toxicity: the quantification of radiation dose is essential to eventually inform dose-risk correlations. This is even more fundamental when radioactive particles are short-range emitters and when they have a chemical speciation that might further concur to the heterogeneity of energy deposition at the cellular and sub-cellular level. To this aim, we need to use computational models. In this work, we made use of a Monte Carlo radiation transport code to perform a computational dosimetric reconstruction for in vitro exposure of cells to tritiated steel particles of micrometric size. Particles of this kind have been identified as worth of attention in nuclear power industry and research: tritium easily permeates in steel elements of nuclear reactor machinery, and mechanical operations on these elements (e.g., sawing) during decommissioning of old facilities can result in particle dispersion, leading to human exposure via inhalation. Considering the software replica of a representative in vitro setup to study the effect of such particles, we therefore modelled the radiation field due to the presence of particles in proximity of cells. We developed a computational approach to reconstruct the dose range to individual cell nuclei in contact with a particle, as well as the fraction of “hit” cells and the average dose for the whole cell population, as a function of particle concentration in the culture medium. The dosimetric analysis also provided the basis to make predictions on tritium-induced DNA damage: we estimated the dose-dependent expected yield of DNA double strand breaks due to tritiated steel particle radiation, as an indicator of their expected biological effectiveness.
Published: 2023

22. PlantACT! – how to tackle the climate crisis

Author: Hirt, Heribert, Al-Babili, Salim, Almeida-Trapp, Marilia, Antoine, Martin, Aranda, Manuel, Bartels, Dorothea, Bennett, Malcolm, Blilou, Ikram, Boer, Damian, Boulouis, Alix, Bowler, Chris, Brunel-Muguet, Sophie, Chardon, Fabien, Colcombet, Jean, Colot, Vincent, Daszkowska-Golec, Agata, Dinneny, Jose, Field, Ben, Froehlich, Katja, Gardener, Catherine, Gojon, Alain, Gomès, Eric, Álvarez, Eva María Gómez, Gutierrez, Crisanto, Havaux, Michel, Hayes, Scott, Heard, Edith, Hodges, Michael, Alghamdi, Amal Khalaf, Laplaze, Laurent, Lauersen, Kyle, Leonhard, Nathalie, Johnson, Xenie, Jones, Jonathan, Kollist, Hannes, Kopriva, Stanislav, Krapp, Anne, Masson, Mauricio Lopez-Portillo, Mccabe, Matthew, Merendino, Livia, Molina, Antonio, Moreno Ramirez, Jose, Müller-Röber, Bernd, Nicolas, Michaël, Nir, Ido, Orduna, Izamar Olivas, Pardo-Tomás, José, Reichheld, Jean-Philippe, Egea, Pedro Luis Rodriguez, Rouached, Hatem, Saad, Maged, Schlögelhofer, Peter, Singh, Kirti, de Smet, Ive, Stanschewski, Clara, Stra, Alice, Tester, Mark, Walshe, Catherine, Weber, Andreas, Weigel, Detlef, Wigge, Philip, Wrzaczek, Michael, Wulff, Brande, Young, Iain, Weber, Andreas P.M., King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division [Thuwal, Arabie saoudite] (BESE), Division of Biological and Environmental Sciences and Engineering, Bioscience Core Labs, Institut des Sciences des Plantes de Montpellier (IPSIM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Montpellier (UM), Red Sea Research Centre (RSRC), IMBIO, Rheinische Friedrich-Wilhelms-Universität Bonn, Centre for Plant Integrative Biology [Nothingham] (CPIB), University of Nottingham, UK (UON), Wageningen University and Research Centre (WUR), Physiologie membranaire et moléculaire du chloroplaste (PMMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de biologie de l'ENS Paris (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Ecophysiologie Végétale, Agronomie et Nutritions (EVA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut National de la Recherche Agronomique (INRA), Ecophysiologie Végétale, Agronomie et Nutritions NCS (EVA), Normandie Université (NU)-Normandie Université (NU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire des interactions plantes micro-organismes (LIPM), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Institut Jean-Pierre Bourgin (IJPB), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut des Sciences des Plantes de Paris-Saclay (IPS2 (UMR_9213 / UMR_1403)), Université d'Évry-Val-d'Essonne (UEVE)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Biologie moléculaire des organismes photosynthétiques (UMR8186), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Ecophysiologie et Génomique Fonctionnelle de la Vigne (UMR EGFV), Université de Bordeaux (UB)-Institut des Sciences de la Vigne et du Vin (ISVV)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Photosynthèse & Environnement (P&E), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Institute of Plant Sciences Paris-Saclay, Institut de Recherche pour le Développement (IRD en Occitanie) (IRD (Occitanie)), Laboratoire Génome et développement des plantes (LGDP), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), and Plant Mineral Nutrition: Sensing, Signaling, and Transport, Plant & Soil Sciences Building
Subjects: water use efficiency, food safety, greenhouse gas emission, climate change, [SDV]Life Sciences [q-bio], [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Biology and Life Sciences, Plant Science, carbon sequestration, nitrogen use efficiency, agriculture
Abstract: International audience; Greenhouse gas (GHG) emissions have created a global climate crisis which requires immediate interventions to mitigate the negative effects on all aspects of life on this planet. As current agriculture and land use contributes up to 25% of total GHG emissions, plant scientists take center stage in finding possible solutions for a transition to sustainable agriculture and land use. In this article, the PlantACT! (Plants for climate ACTion!) initiative of plant scientists lays out a road map of how and in which areas plant scientists can contribute to finding immediate, mid-term, and long-term solutions, and what changes are necessary to implement these solutions at the personal, institutional, and funding levels.
Published: 2023

23. Approaches and determinants to sustainably improve crop production

Author: Alain Gojon, Laurent Nussaume, Doan T. Luu, Erik H. Murchie, Alexandra Baekelandt, Vandasue Lily Rodrigues Saltenis, Jean‐Pierre Cohan, Thierry Desnos, Dirk Inzé, John N. Ferguson, Emmanuel Guiderdonni, Anne Krapp, René Klein Lankhorst, Christophe Maurel, Hatem Rouached, Martin A. J. Parry, Mathias Pribil, Lars B. Scharff, Philippe Nacry, Institut des Sciences des Plantes de Montpellier (IPSIM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Montpellier (UM), Plant Environmental Physiology and Stress Signaling (PEPSS), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of Nottingham, UK (UON), Universiteit Gent = Ghent University (UGENT), Vlaams Instituut voor Biotechnologie [Ghent, Belgique] (VIB), Copenhagen Plant Science Center (CPSC), Department of Plant and Environmental Sciences [Copenhagen], Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), ARVALIS - Institut du végétal [Paris], University of Cambridge [UK] (CAM), Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Département Systèmes Biologiques (Cirad-BIOS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Institut Jean-Pierre Bourgin (IJPB), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Wageningen University and Research [Wageningen] (WUR), Lancaster Environment Centre, Lancaster University, European Project: 817690,H2020, Gojon, A [0000-0001-5412-8606], Nussaume, L [0000-0002-9445-2563], Luu, DT [0000-0001-9765-2125], Murchie, EH [0000-0002-7465-845X], Baekelandt, A [0000-0003-0816-7115], Rodrigues Saltenis, VL [0000-0002-1455-7171], Cohan, JP [0000-0003-2117-7027], Desnos, T [0000-0002-6585-1362], Inzé, D [0000-0002-3217-8407], Ferguson, JN [0000-0003-3603-9997], Guiderdonni, E [0000-0003-2760-2864], Krapp, A [0000-0003-2034-5615], Klein Lankhorst, R [0000-0003-1845-8733], Maurel, C [0000-0002-4255-6440], Rouached, H [0000-0002-7751-0477], Parry, MAJ [0000-0002-4477-672X], Pribil, M [0000-0002-9174-9548], Scharff, LB [0000-0003-0210-3428], Nacry, P [0000-0001-7766-4989], and Apollo - University of Cambridge Repository
Subjects: 0106 biological sciences, Agriculture and Food Sciences, PHOSPHORUS-ACQUISITION, [SDV]Life Sciences [q-bio], NITROGEN ASSIMILATION, drought, UTILIZATION EFFICIENCY, SALT TOLERANCE, 01 natural sciences, nitrogen, climate change mitigation, salinity, heat stress, 03 medical and health sciences, DROUGHT TOLERANCE, AFFINITY PHOSPHATE TRANSPORTER, Life Science, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Renewable Energy, TRANSCRIPTION FACTOR, 030304 developmental biology, phosphate, 2. Zero hunger, 0303 health sciences, Sustainability and the Environment, Renewable Energy, Sustainability and the Environment, fungi, BioSolar Cells, Biology and Life Sciences, food and beverages, Forestry, 15. Life on land, WATER-USE, 13. Climate action, ABSCISIC-ACID RECEPTORS, Agronomy and Crop Science, 010606 plant biology & botany, Food Science, HEAT-STRESS
Abstract: International audience; Plant scientists and farmers are facing major challenges in providing food and nutritional security for a growing population, while preserving natural resources and biodiversity. Moreover, this should be done while adapting agriculture to climate change and by reducing its carbon footprint. To address these challenges, there is an urgent need to breed crops that are more resilient to suboptimal environments. Huge progress has recently been made in understanding the physiological, genetic and molecular bases of plant nutrition and environmental responses, paving the way towards a more sustainable agriculture. In this review, we present an overview of these progresses and strategies that could be developed to increase plant nutrient use efficiency and tolerance to abiotic stresses. As illustrated by many examples, they already led to promising achievements and crop improvements. Here, we focus on nitrogen and phosphate uptake and use efficiency and on adaptation to drought, salinity and heat stress. These examples first show the necessity of deepening our physiological and molecular understanding of plant environmental responses. In particular, more attention should be paid to investigate stress combinations and stress recovery and acclimation that have been largely neglected to date. It will be necessary to extend these approaches from model plants to crops, to unravel the relevant molecular targets of biotechnological or genetic strategies directly in these species. Similarly, sustained efforts should be done for further exploring the genetic resources available in these species, as well as in wild species adapted to unfavourable environments. Finally, technological developments will be required to breed crops that are more resilient and efficient. This especially relates to the development of multiscale phenotyping under field conditions and a wide range of environments, and use of modelling and big data management to handle the huge amount of information provided by the new molecular, genetic and phenotyping techniques.
Published: 2023

24. Genetic control of rhizosheath formation in pearl millet

Author: de la Fuente Cantó, C., Diouf, M, Ndour, P, Debieu, M., Grondin, A., Passot, S., Champion, A., Barrachina, C., Pratlong, M., Gantet, P., Assigbetsé, K., Kane, N., Cubry, P., Diedhiou, A, Heulin, T., Achouak, W., Vigouroux, Y., Cournac, Laurent, Laplaze, Laurent, Diversité, adaptation, développement des plantes (UMR DIADE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Université de Montpellier (UM), Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (UMR Eco&Sols), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), LMI IESOL Intensification Ecologique des Sols Cultivés en Afrique de l’Ouest [Dakar] (IESOL), Institut de recherche pour le développement (IRD [Sénégal]), Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD), LMI Adaptation des Plantes et microorganismes associés aux Stress Environnementaux [Dakar] (LAPSE), Institut de Recherche pour le Développement (IRD), Centre d'Etude Regional Pour l'Amelioration de l'Adaptation A la Secheresse (CERAAS), Institut de Génomique Fonctionnelle - Montpellier GenomiX (IGF MGX), Institut de Génomique Fonctionnelle (IGF), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-BioCampus (BCM), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Ecosystèmes continentaux et risques environnementaux (ECCOREV), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), French National Research Institute for Sustainable Development (IRD), CGIAR Research Programme on Grain Legumes and Dryland Cereals (GLDC), NewPearl grant in the frame of the CERES initiative by the Agropolis Fondation, Fondazione Cariplo (No FC 2013-0891), ANR-17-CE20-0022,RootAdapt,Traits racinaires pour l'adaptation du mil au climat futur en Afrique de l'Ouest(2017), ANR-16-IDEX-0006,MUSE,MUSE(2016), ANR-10-LABX-0001,AGRO,Agricultural Sciences for sustainable Development(2010), Fournier, Dominique, Traits racinaires pour l'adaptation du mil au climat futur en Afrique de l'Ouest - - RootAdapt2017 - ANR-17-CE20-0022 - AAPG2017 - VALID, MUSE - - MUSE2016 - ANR-16-IDEX-0006 - IDEX - VALID, and Agricultural Sciences for sustainable Development - - AGRO2010 - ANR-10-LABX-0001 - LABX - VALID
Subjects: [SDV.GEN.GPL]Life Sciences [q-bio]/Genetics/Plants genetics, [SDV.GEN.GPL] Life Sciences [q-bio]/Genetics/Plants genetics, food and beverages
Abstract: International audience; The rhizosheath, the layer of soil that adheres strongly to roots, influences water and nutrients acquisition. Pearl millet is a cereal crop that plays a major role for food security in arid regions of sub-Saharan Africa and India. We previously showed that root-adhering soil mass is a heritable trait in pearl millet and that it correlates with changes in rhizosphere microbiota structure and functions. Here, we studied the correlation between root-adhering soil mass and root hair development, root architecture, and symbiosis with arbuscular mycorrhizal fungi and we analysed the genetic control of this trait using genome wide association (GWAS) combined with bulk segregant analysis and gene expression studies. Root-adhering soil mass was weakly correlated only to root hairs traits in pearl millet. Twelve QTLs for rhizosheath formation were identified by GWAS. Bulk segregant analysis on a biparental population validated five of these QTLs. Combining genetics with a comparison of global gene expression in the root tip of contrasted inbred lines revealed candidate genes that might control rhizosheath formation in pearl millet. Our study indicates that rhizosheath formation is under complex genetic control in pearl millet and suggests that it is mainly regulated by root exudation.
Published: 2022

25. Combusted-diesel additives containing CeO 2 nanomaterials shape methanogenic pathways during sludge digestion and enhance biogas production

Author: Mélanie Auffan, Abdoul Karim Kabore, Anais Cuny, Oulfat Amin Ali, Mohammed Barakat, Bernard Angeletti, Olivier Proux, Jean-Yves Bottero, Nicolas Roche, Catherine Santaella, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Université Mohammed VI Polytechnique [Ben Guerir] (UM6P), Excellence Initiative of Aix-Marseille University - A*MIDEX, a French 'Investissements d’Avenir' program, through its associated Labex SERENADE project, and Duke University [Durham]
Subjects: [SDE.IE]Environmental Sciences/Environmental Engineering, Materials Science (miscellaneous), [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, General Environmental Science
Abstract: International audience; This study addressed the impact of nanomaterials on anaerobic digestion and biogas production (methanogenesis pathways) whencontaminanting aerobic sludge generated during wastewater treatment. Our experimental system was based on bioreactor operationalparameters aligned with the operating conditions used in wastewater treatment plants (WWTP), a contamination scenario considering thetreatment of nano-enabled products at the last stages of their life cycle, and nanomaterial concentrations close to those predicted in WWTP.The physico-chemical, microbiological and chemical engineering proxies studied all concluded that combusted nanoCeO2-enabled fuel additivestransiently increased EPS production and specific hydrolytic enzymatic activities without altering the aerobic sludge microbial communitystructure nor the C, P, N removal capacity (spiked concentrations of 130 µg.L-1 during aerobic sludge production). However, the presence in theaerobic sludge biosolids of 99.9 % of the total CeO2 injected (without any change in speciation) altered the production, structure, and activity ofthe anaerobic sludge during digestion (impacting the EPS, ATP, lipase and α–glucosidase activities). Interestingly, these modifications of theanaerobic sludge activity shaped the methanogenesis pathways from acetoclastic to hydrogenotrophic and enhanced the biogas productionwith a significant increase in generated H2. In the context of developing a sustainable energy supply, we observed a continuous improvementof the biogas production in the contaminated bioreactor, which could increase the energy recovery potential of WWTPs.
Published: 2022

26. Use of an Acellular Assay to Study Interactions between Actinides and Biological or Synthetic Ligands

Author: Anne Van der Meeren, Catherine Berthomieu, Agnès Moureau, Martine Defrance, Nina M. Griffiths, Laboratoire de Radiotoxicologie (LRT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Interactions Protéine Métal (IPM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Actinoid Series Elements, Americium, actinides, [SDV.TOX.TCA]Life Sciences [q-bio]/Toxicology/Toxicology and food chain, Pentetic Acid, Ligands, Biochemistry, Plutonium, bioavailability, bioligands, protein interaction, chelation, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], Molecular Biology
Abstract: International audience; Speciation of actinides, and more particularly bioligand-binding ability, influences in vivo behavior. Understanding these interactions is essential for estimation of radiological dose and improvement of decorporation strategies for accidentally contaminated victims. Because the handling of actinides imposes overwhelming difficulties, in vitro assays carried out in physiological conditions are lacking and data regarding such interactions are scarce. In this study, we used a bi-compartmental and dynamic assay, providing physiological conditions (presence of inorganic ions, pH, temperature) to explore interactions between the actinides plutonium (Pu) and americium (Am) and endogenous (proteins transferrin and ferritin) or exogenous ligands (the chelating agent diethylenetriaminpentaacetic acid, DTPA). In this assay, an agarose gel represents the retention compartment of actinides and a dynamic fluid phase, the transfer compartment. The proportion of actinides transferred from static to dynamic phase reflects interactions between Pu/Am and various ligands. The results show differences in the formation of actinide-protein or actinide-DTPA complexes in physiologically relevant media depending on which ligand is present and where. We observed differential behavior for Pu and Am similar to in vivo studies. Thus, our assay may be used to determine the ability of various actinides to interact with specific proteins or with drug candidates for decorporation in complex physiologically relevant environments.
Published: 2022
Full Text: View/download PDF

27. Biokinetics and internal dosimetry of tritiated steel particles

Author: Rachel Smith, Michele Ellender, Chang Guo, Derek Hammond, Adam Laycock, Martin O. Leonard, Matthew Wright, Michael Davidson, Véronique Malard, Mickaël Payet, Christian Grisolia, Eric Blanchardon, UK Health Security Agency [London] (UKHSA), Interactions Protéine Métal (IPM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Bureau d'expertise en radioprotection de la population (IRSN/PSE-ENV/SEREN/BERAP), Service d'expertise et d'étude en radioprotection des populations et de la radioactivité dans l'environnement (IRSN/PSE-ENV/SEREN), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), and European Project: 754586,TRANSAT
Subjects: tritiated steel particles, Chemical Health and Safety, dosimetry, tritium, Health, Toxicology and Mutagenesis, [SDV]Life Sciences [q-bio], dissolution, rat, dose coefficients, biokinetics, Toxicology
Abstract: Decommissioning fission and fusion facilities can result in the production of airborne particles containing tritium that could inadvertently be inhaled by workers directly involved in the operations, and potentially others, resulting in internal exposures to tritium. Of particular interest in this context, given the potentially large masses of material involved, is tritiated steel. The International Commission on Radiological Protection (ICRP) has recommended committed effective dose coefficients for inhalation of some tritiated materials, but not specifically for tritiated steel. The lack of a dose coefficient for tritiated steel is a concern given the potential importance of the material. To address this knowledge gap, a “dissolution” study, in vivo biokinetic study in a rodent model (1 MBq intratracheal instillation, 3-month follow-up) and associated state-of-the-art modelling were undertaken to derive dose coefficients for model tritiated steel particles. A committed effective dose coefficient for the inhalation of 3.3 × 10−12 Sv Bq−1 was evaluated for the particles, reflecting an activity median aerodynamic diameter (AMAD) of 13.3 µm, with the value for a reference AMAD for workers (5 µm) of 5.6 × 10−12 Sv Bq−1 that may be applied to occupational inhalation exposure to tritiated steel particles.
Published: 2022

28. A non specific Lipid Transfer Protein with potential functions in infection and nodulation

Author: Mélanie Gasser, Nicole Alloisio, Pascale Fournier, Severine Balmand, Ons Kharrat, Joris Tulumello, Lorena Carro, Abdelaziz Heddi, Pedro Da Silva, Philippe Normand, Petar Pujic, Hasna Boubakri, Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Biologie Fonctionnelle, Insectes et Interactions (BF2I), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université de Lyon, Unité de recherche Génétique Microbienne (UGM), and Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: Physiology, Nitrogen Fixation, [SDV]Life Sciences [q-bio], Frankia, General Medicine, Symbiosis, Plant Roots, Agronomy and Crop Science
Abstract: The response of Alnus glutinosa to Frankia alni ACN14a is driven by several sequential physiological events from calcium spiking and root-hair deformation to the development of the nodule. Early stages of actinorhizal symbiosis were monitored at the transcriptional level to observe plant host responses to Frankia alni. Forty-two genes were significantly upregulated in inoculated compared with noninoculated roots. Most of these genes encode proteins involved in biological processes induced during microbial infection, such as oxidative stress or response to stimuli, but a large number of them are not differentially modulated or downregulated later in the process of nodulation. In contrast, several of them remained upregulated in mature nodules, and this included the gene most upregulated, which encodes a nonspecific lipid transfer protein (nsLTP). Classified as an antimicrobial peptide, this nsLTP was immunolocalized on the deformed root-hair surfaces that are points of contact for Frankia spp. during infection. Later in nodules, it binds to the surface of F. alni ACN14a vesicles, which are the specialized cells for nitrogen fixation. This nsLTP, named AgLTP24, was biologically produced in a heterologous host and purified for assay on F. alni ACN14a to identify physiological effects. Thus, the activation of the plant immunity response occurs upon first contact, while the recognition of F. alni ACN14a genes switches off part of the defense system during nodulation. AgLTP24 constitutes a part of the defense system that is maintained all along the symbiosis, with potential functions such as the formation of infection threads or nodule primordia to the control of F. alni proliferation. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
Published: 2022

29. Fatty acid export (FAX) proteins contribute to oil production in the green microalga Chlamydomonas reinhardtii

Author: Janick Peter, Marie Huleux, Benjamin Spaniol, Frederik Sommer, Jens Neunzig, Michael Schroda, Yonghua Li-Beisson, Katrin Philippar, Environnement, Bioénergie, Microalgues et Plantes (EBMP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: fatty acid transport, endoplasmic reticulum, chloroplast, microalgae, [SDV]Life Sciences [q-bio], Biochemistry, Genetics and Molecular Biology (miscellaneous), Molecular Biology, Biochemistry, oil production
Abstract: In algae and land plants, transport of fatty acids (FAs) from their site of synthesis in the plastid stroma to the endoplasmic reticulum (ER) for assembly into acyl lipids is crucial for cellular lipid homeostasis, including the biosynthesis of triacylglycerol (TAG) for energy storage. In the unicellular green alga Chlamydomonas reinhardtii, understanding and engineering of these processes is of particular interest for microalga-based biofuel and biomaterial production. Whereas in the model plant Arabidopsis thaliana, FAX (fatty acid export) proteins have been associated with a function in plastid FA-export and hence TAG synthesis in the ER, the knowledge on the function and subcellular localization of this protein family in Chlamydomonas is still scarce. Among the four FAX proteins encoded in the Chlamydomonas genome, we found Cr-FAX1 and Cr-FAX5 to be involved in TAG production by functioning in chloroplast and ER membranes, respectively. By in situ immunolocalization, we show that Cr-FAX1 inserts into the chloroplast envelope, while Cr-FAX5 is located in ER membranes. Severe reduction of Cr-FAX1 or Cr-FAX5 proteins by an artificial microRNA approach results in a strong decrease of the TAG content in the mutant strains. Further, overexpression of chloroplast Cr-FAX1, but not of ER-intrinsic Cr-FAX5, doubled the content of TAG in Chlamydomonas cells. We therefore propose that Cr-FAX1 in chloroplast envelopes and Cr-FAX5 in ER membranes represent a basic set of FAX proteins to ensure shuttling of FAs from chloroplasts to the ER and are crucial for oil production in Chlamydomonas.
Published: 2022

30. New perspectives on the molecular mechanisms of stress signalling by the nucleotide guanosine tetraphosphate (ppGpp), an emerging regulator of photosynthesis in plants and algae

Author: Marwa Mehrez, Shanna Romand, Ben Field, Luminy Génétique et Biophysique des Plantes (LGBP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université de Tunis, and ANR-17-CE13-0005,G4PLAST,Mecanismes d'acclimation aux stress par la voie conservée de signalisation du (p)ppGpp dans le chloroplaste.(2017)
Subjects: algae, photosynthesis, ppGpp, chloroplast, Physiology, [SDV]Life Sciences [q-bio], [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Plant Science, guanosine tetraphosphate, RelA SpoT Homologue, nitrogen
Abstract: International audience; The nucleotides guanosine tetraphosphate and guanosine pentaphosphate (together (p)ppGpp) are found in a wide range of prokaryotic and eukaryotic organisms where they are associated with stress signalling. In this review, we will discuss recent research highlighting the role of (p)ppGpp signalling as a conserved regulator of photosynthetic activity in the chloroplasts of plants and algae, and the latest discoveries that open up new perspectives on the emerging roles of (p)ppGpp in acclimation to environmental stress. We explore how rapid advances in the study of (p)ppGpp signalling in prokaryotes are now revealing large gaps in our understanding of the molecular mechanisms of signalling by (p)ppGpp and related nucleotides in plants and algae. Filling in these gaps is likely to lead to the discovery of conserved as well as new plant- and algal-specific (p)ppGpp signalling mechanisms that will offer new insights into the taming of the chloroplast and the regulation of stress tolerance.; Les nucléotides guanosine tétraphosphate et guanosine pentaphosphate (ensemble (p)ppGpp) sont présents dans un large éventail d'organismes procaryotes et eucaryotes où ils sont associés à la signalisation du stress. Dans cette revue, nous abordons les recherches récentes qui mettent en évidence le rôle de la signalisation du (p)ppGpp en tant que régulateur conservé de l'activité photosynthétique dans les chloroplastes des plantes et des algues, ainsi que les dernières découvertes qui ouvrent de nouvelles perspectives sur les rôles émergents du (p)ppGpp dans l'acclimatation au stress environnemental. Nous explorons comment les progrès rapides dans l'étude de la signalisation du (p)ppGpp chez les procaryotes révèlent maintenant de grandes lacunes dans notre compréhension des mécanismes moléculaires de la signalisation par le (p)ppGpp et les nucléotides apparentés chez les plantes et les algues. Combler ces lacunes conduira probablement à la découverte de mécanismes de signalisation par (p)ppGpp conservés ou nouveaux, spécifiques aux plantes et aux algues, qui offriront de nouvelles perspectives sur l'apprivoisement du chloroplaste et la régulation de la tolérance au stress.
Published: 2022

31. Interplay of surface interaction and magnetic torque in single-cell motion of magnetotactic bacteria in microfluidic confinement

Author: Elisa Cerdá-Doñate, Mohammad A Charsooghi, Agnese Codutti, Hubert M Taïeb, Tom Robinson, Damien Faivre, Stefan Klumpp, Department of Biomaterials, Max‐Planck‐Institute of Colloids and Interfaces, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Microbiologie Environnementale et Moléculaire (MEM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Georg-August-University = Georg-August-Universität Göttingen
Subjects: Magnetics, Magnetic Fields, Torque, General Immunology and Microbiology, General Neuroscience, [SDV]Life Sciences [q-bio], Gram-Negative Bacteria, Microfluidics, General Medicine, Magnetospirillum, General Biochemistry, Genetics and Molecular Biology
Abstract: International audience; Swimming microorganisms often experience complex environments in their natural habitat. The same is true for microswimmers in envisioned biomedical applications. The simple aqueous conditions typically studied in the lab differ strongly from those found in these environments and often exclude the effects of small volume confinement or the influence that external fields have on their motion. In this work, we investigate magnetically steerable microswimmers, specifically magnetotactic bacteria, in strong spatial confinement and under the influence of an external magnetic field. We trap single cells in micrometer-sized microfluidic chambers and track and analyze their motion, which shows a variety of different trajectories, depending on the chamber size and the strength of the magnetic field. Combining these experimental observations with simulations using a variant of an active Brownian particle model, we explain the variety of trajectories by the interplay between the wall interactions and the magnetic torque. We also analyze the pronounced cell-to-cell heterogeneity, which makes single-cell tracking essential for an understanding of the motility patterns. In this way, our work establishes a basis for the analysis and prediction of microswimmer motility in more complex environments.
Published: 2022

32. Topoisomerase VI participates in an insulator-like function that prevents H3K9me2 spreading

Author: Louis-Valentin Méteignier, Cécile Lecampion, Florent Velay, Cécile Vriet, Laura Dimnet, Martin Rougée, Christian Breuer, Ludivine Soubigou-Taconnat, Keiko Sugimoto, Fredy Barneche, Christophe Laloi, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Luminy Génétique et Biophysique des Plantes (LGBP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Ecologie et biologie des interactions (EBI), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), Institut de biologie de l'ENS Paris (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), RIKEN Center for Sustainable Resource Science [Yokohama] (RIKEN CSRS), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Institut des Sciences des Plantes de Paris-Saclay (IPS2 (UMR_9213 / UMR_1403)), Université d'Évry-Val-d'Essonne (UEVE)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Velux Stiftung (Switzerland)., L.D. was supported by the Commissariat à l’énergie atomique et aux énergies alternatives and Région Provence-Alpes-Côte d’Azur. F.V. is a recipient of a PhD fellowship from the French Ministry of Higher Education, Research and Innovation., Mass spectrometry analysis was performed at the IMM platform supported by a grant from the Groupement d’Intérêt Scientifique (GIS) Infrastrutures en Biologie Sante et Agronomie (IBiSA)., ANR-14-CE02-0010,SLOSAM,Signalisation du stress photooxydant dans les mécanismes d'acclimatation des plantes aux changements climatiques(2014), ANR-10-LABX-0054,MEMOLIFE,Memory in living systems: an integrated approach(2010), ANR-18-CE13-0004,ChromaLight,Functional links between nuclear architecture and epigenome reprogramming during plant adaptive responses to light(2018), ANR-17-CE12-0026,RiboStress,Interconnections génétiques, épigénétiques et protéiques au cours de la réorganisation fonctionnelle du nucléole et des réponses aux stress(2017), ANR-10-LABX-0040,SPS,Saclay Plant Sciences(2010), ANR-10-INBS-0009,France-Génomique,Organisation et montée en puissance d'une Infrastructure Nationale de Génomique(2010), ANR-10-JCJC-1205,CHROS,CHromatine et ROS : Rôle du facteur de remodelage de la chromatine topoisomérase VI dans la réponse transcriptionnelle des plantes à l'oxygène singulet et autres formes actives de l'oxygène lors de conditions de stress abiotique.(2010), BARNECHE, Fredy, Appel à projets générique - Signalisation du stress photooxydant dans les mécanismes d'acclimatation des plantes aux changements climatiques - - SLOSAM2014 - ANR-14-CE02-0010 - Appel à projets générique - VALID, Memory in living systems: an integrated approach - - MEMOLIFE2010 - ANR-10-LABX-0054 - LABX - VALID, APPEL À PROJETS GÉNÉRIQUE 2018 - Functional links between nuclear architecture and epigenome reprogramming during plant adaptive responses to light - - ChromaLight2018 - ANR-18-CE13-0004 - AAPG2018 - VALID, Interconnections génétiques, épigénétiques et protéiques au cours de la réorganisation fonctionnelle du nucléole et des réponses aux stress - - RiboStress2017 - ANR-17-CE12-0026 - AAPG2017 - VALID, Saclay Plant Sciences - - SPS2010 - ANR-10-LABX-0040 - LABX - VALID, Organisation et montée en puissance d'une Infrastructure Nationale de Génomique - - France-Génomique2010 - ANR-10-INBS-0009 - INBS - VALID, Jeunes Chercheuses et Jeunes Chercheurs - CHromatine et ROS : Rôle du facteur de remodelage de la chromatine topoisomérase VI dans la réponse transcriptionnelle des plantes à l'oxygène singulet et autres formes actives de l'oxygène lors de conditions de stress abiotique. - - CHROS2010 - ANR-10-JCJC-1205 - JCJC - VALID, and Aix Marseille Université (AMU)
Subjects: Topoisomerase, Multidisciplinary, Arabidopsis Proteins, [SDV]Life Sciences [q-bio], Arabidopsis, [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, Methionine Adenosyltransferase, Chromatin, Heterochromatin spreading, Euchromatin, Histones, [SDV] Life Sciences [q-bio], Topoisomerase VI, [SDV.GEN.GPL]Life Sciences [q-bio]/Genetics/Plants genetics, [SDV.BV.AP]Life Sciences [q-bio]/Vegetal Biology/Plant breeding, Epigenome, DNA Topoisomerases, Type II, Heterochromatin, [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], [SDV.GEN.GPL] Life Sciences [q-bio]/Genetics/Plants genetics, Euchromatin islands, DNA Transposable Elements, Insulator
Abstract: The organization of the genome into transcriptionally active and inactive chromatin domains requires well-delineated chromatin boundaries and insulator functions in order to maintain the identity of adjacent genomic loci with antagonistic chromatin marks and functionality. In plants that lack known chromatin insulators, the mechanisms that prevent heterochromatin spreading into euchromatin remain to be identified. Here, we show that DNA Topoisomerase VI participates in a chromatin boundary function that safeguards the expression of genes in euchromatin islands within silenced heterochromatin regions. While some transposable elements are reactivated in mutants of the Topoisomerase VI complex, genes insulated in euchromatin islands within heterochromatic regions of the Arabidopsis thaliana genome are specifically down-regulated. H3K9me2 levels consistently increase at euchromatin island loci and decrease at some transposable element loci. We further show that Topoisomerase VI physically interacts with S-adenosylmethionine synthase methionine adenosyl transferase 3 (MAT3), which is required for H3K9me2. A Topoisomerase VI defect affects MAT3 occupancy on heterochromatic elements and its exclusion from euchromatic islands, thereby providing a possible mechanistic explanation to the essential role of Topoisomerase VI in the delimitation of chromatin domains.
Published: 2022

33. Plastidial and cytosolic thiol reductases participate in the control of stomatal functioning

Author: Dominique Rumeau, Patricia Henri, Sabine Brugière, Pascal Rey, Yohann Couté, Jean-Philippe Reichheld, Jean‐luc Montillet, Nathalie Leonhardt, Damien Rondet, Couté, Yohann, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la dynamique des protéomes (EDyP), BioSanté (UMR BioSanté), Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Protéines de Protection des Végétaux (PPV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Laboratoire Génome et développement des plantes (LGDP), Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and Signalisation de l'Adaptation des Végétaux à l'Environnement (SAVE)
Subjects: 0106 biological sciences, 0301 basic medicine, Arabidopsis thaliana, Physiology, [SDV]Life Sciences [q-bio], stomata, Arabidopsis, Plant Science, 01 natural sciences, chemistry.chemical_compound, Cytosol, Gene Expression Regulation, Plant, thiol reductase, Guard cell, Glutaredoxin, Plastids, Abscisic acid, ComputingMilieux_MISCELLANEOUS, biology, peroxiredoxin, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, Cell biology, Phenotype, [SDV.BBM.GTP] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], Thioredoxin, Oxidoreductases, signaling, Stomatal conductance, Models, Biological, [SDV.BV.BOT] Life Sciences [q-bio]/Vegetal Biology/Botanics, 03 medical and health sciences, proteomics, [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Hydrogen Peroxide, thioredoxin, glutaredoxin, biology.organism_classification, Gene Ontology, 030104 developmental biology, chemistry, Mutation, Plant Stomata, guard cell, Transcriptome, Peroxiredoxin, Abscisic Acid, 010606 plant biology & botany
Abstract: International audience; Stomatal movements via the control of gas exchanges determine plant growth in relation to environmental stimuli through a complex signalling network involving reactive oxygen species that lead to post‐translational modifications of Cys and Met residues, and alter protein activity and/or conformation. Thiol‐reductases (TRs), which include thioredoxins, glutaredoxins (GRXs) and peroxiredoxins (PRXs), participate in signalling pathways through the control of Cys redox status in client proteins. Their involvement in stomatal functioning remains poorly characterized. By performing a mass spectrometry‐based proteomic analysis, we show that numerous thiol reductases, like PRXs, are highly abundant in guard cells. When investigating various Arabidopsis mutants impaired in the expression of TR genes, no change in stomatal density and index was noticed. In optimal growth conditions, a line deficient in cytosolic NADPH‐thioredoxin reductases displayed higher stomatal conductance and lower leaf temperature evaluated by thermal infrared imaging. In contrast, lines deficient in plastidial 2‐CysPRXs or type‐II GRXs exhibited compared to WT reduced conductance and warmer leaves in optimal conditions, and enhanced stomatal closure in epidermal peels treated with abscisic acid or hydrogen peroxide. Altogether, these data strongly support the contribution of thiol redox switches within the signalling network regulating guard cell movements and stomatal functioning.
Published: 2021

34. Structural characterization, functional and biological activities of an exopolysaccharide produced by probiotic Bacillus licheniformis AG-06 from Indian polyherbal fermented traditional medicine

Author: Ramasamy Thirumurugan, Arivalagan Pugazhendhi, Krishnamurthy Mathivanan, Soundarapandian Sekar, Annadurai Vinothkanna, Yongkun Ma, Perumalsamy Balaji, Ganesan Sathiyanarayanan, JiangSu University, Bharathidasan University [Tiruchirappalli, India], Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Central South University [Changsha], and Ton Duc Thang University [Hô-Chi-Minh-City]
Subjects: Magnetic Resonance Spectroscopy, Free Radicals, Rhamnose, DPPH, [SDV]Life Sciences [q-bio], Mannose, Antineoplastic Agents, 02 engineering and technology, Xylose, Biochemistry, Antioxidants, 03 medical and health sciences, chemistry.chemical_compound, Structural Biology, Spectroscopy, Fourier Transform Infrared, Bacillus licheniformis, Humans, Molecular Biology, Chromatography, High Pressure Liquid, 030304 developmental biology, 0303 health sciences, ABTS, Traditional medicine, biology, Probiotics, Polysaccharides, Bacterial, General Medicine, 021001 nanoscience & nanotechnology, biology.organism_classification, chemistry, A549 Cells, Galactose, Fermentation, Medicine, Traditional, 0210 nano-technology
Abstract: International audience; An exopolysaccharide (EPS) was purified from the probiotic bacterium Bacillus licheniformis AG-06 isolated from the polyherbal fermented traditional medicine (Ashwagandharishta) of Indian Ayurveda. High-performance liquid chromatography (HPLC) based compositional analysis exhibits the heteropolymeric nature of the EPS consisting of galactose, rhamnose, xylose, mannose, and glucose, as the monomeric units. Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic analyses confirm the presence of typical carbohydrate polymer functional groups and structural units, respectively. The purified EPS demonstrates the web-like fibrous and porous nature in scanning electron microscopic and atomic force microscopic studies. The purified EPS had shown 71.83% and 67.79% of flocculation and emulsification activities, respectively. Antioxidant activity was evaluated against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), nitric oxide, and superoxide free radicals and the scavenging actions were increased in a dose-dependent manner. Moreover, the purified EPS exhibits a significant cytotoxic activity against the human lung carcinoma cells (A549), which strongly suggests the anticancer potential of the EPS derived from B. licheniformis AG-06.
Published: 2021

35. Role of an ancient light-harvesting protein of PSI in light absorption and photoprotection

Author: Anastasios Melis, Thien Crisanto, Hiroko Takahashi, Alessandro Alboresi, Krishna K. Niyogi, Tomas Morosinotto, Adrien Burlacot, Oliver Dautermann, Masakazu Iwai, Gilles Peltier, Qinhua Gan, Yandu Lu, Environnement, Bioénergie, Microalgues et Plantes (EBMP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Bioénergie et Microalgues (EBM), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Photosystem I, 0106 biological sciences, 0301 basic medicine, Light, [SDV]Life Sciences [q-bio], Mutant, photosystem, General Physics and Astronomy, 01 natural sciences, antenna, chemistry.chemical_compound, Nannochloropsis, Photosynthesis, Multidisciplinary, biology, Endosymbiosis, Chemistry, light-harvesting, Adaptation, Physiological, Cell biology, Antenna complex, Stramenopiles, Physiological, 1.1 Normal biological development and functioning, Science, Article, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, Algae, Underpinning research, Light responses, Adaptation, photosynthesis, Photosystem I Protein Complex, Chlorophyll A, Wild type, General Chemistry, light-harvesting, Nannochloropsis, photoprotection, photosystem, photosynthesis, antenna, biology.organism_classification, photoprotection, 030104 developmental biology, Chlorophyll, Photoprotection, Mutation, Generic health relevance, Chlorophyll Binding Proteins, Function (biology), 010606 plant biology & botany
Abstract: Diverse algae of the red lineage possess chlorophyll a-binding proteins termed LHCR, comprising the PSI light-harvesting system, which represent an ancient antenna form that evolved in red algae and was acquired through secondary endosymbiosis. However, the function and regulation of LHCR complexes remain obscure. Here we describe isolation of a Nannochloropsis oceanica LHCR mutant, named hlr1, which exhibits a greater tolerance to high-light (HL) stress compared to the wild type. We show that increased tolerance to HL of the mutant can be attributed to alterations in PSI, making it less prone to ROS production, thereby limiting oxidative damage and favoring growth in HL. HLR1 deficiency attenuates PSI light-harvesting capacity and growth of the mutant under light-limiting conditions. We conclude that HLR1, a member of a conserved and broadly distributed clade of LHCR proteins, plays a pivotal role in a dynamic balancing act between photoprotection and efficient light harvesting for photosynthesis., LHCR proteins are ancient chlorophyll a-binding antennas that evolved in diverse algae of the red lineage. Here Lu et al. characterize a red lineage LHCR mutant and show reduced oxidative damage in high light but attenuated growth under low light, thus demonstrating how LHCR proteins impact the balance between photoprotection and light harvesting.
Published: 2021

36. Alternative photosynthesis pathways drive the algal CO2-concentrating mechanism

Author: Adrien Burlacot, Ousmane Dao, Pascaline Auroy, Stephan Cuiné, Yonghua Li-Beisson, Gilles Peltier, Environnement, Bioénergie, Microalgues et Plantes (EBMP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Multidisciplinary, [SDV]Life Sciences [q-bio]
Abstract: International audience; Global photosynthesis consumes ten times more CO2 than net anthropogenic emissions, and microalgae account for nearly half of this consumption1. The high efficiency of algal photosynthesis relies on a mechanism concentrating CO2 (CCM) at the catalytic site of the carboxylating enzyme RuBisCO, which enhances CO2 fixation2. Although many cellular components involved in the transport and sequestration of inorganic carbon have been identified3,4, how microalgae supply energy to concentrate CO2 against a thermodynamic gradient remains unknown4–6. Here we show that in the green alga Chlamydomonas reinhardtii, the combined action of cyclic electron flow and O2 photoreduction—which depend on PGRL1 and flavodiiron proteins, respectively—generate a low luminal pH that is essential for CCM function. We suggest that luminal protons are used downstream of thylakoid bestrophin-like transporters, probably for the conversion of bicarbonate to CO2. We further establish that an electron flow from chloroplast to mitochondria contributes to energizing non-thylakoid inorganic carbon transporters, probably by supplying ATP. We propose an integrated view of the network supplying energy to the CCM, and describe how algal cells distribute energy from photosynthesis to power different CCM processes. These results suggest a route for the transfer of a functional algal CCM to plants to improve crop productivity.
Published: 2022

37. Phytobeneficial traits of rhizobacteria under the control of multiple molecular dialogues

Author: Arnaud Laveilhé, Sylvain Fochesato, David Lalaouna, Thierry Heulin, Wafa Achouak, Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Architecture et Réactivité de l'ARN (ARN), Institut de biologie moléculaire et cellulaire (IBMC), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Bacteria, Iron, Rhizosphere, Fungi, food and beverages, Bioengineering, Applied Microbiology and Biotechnology, Biochemistry, Soil Microbiology, Biotechnology, Alphaproteobacteria, Plant Diseases
Abstract: International audience; Pseudomonads play crucial roles in plant growth promotion and control of plant diseases. However, under natural conditions, other microorganisms competing for the same nutrient resources in the rhizosphere may exert negative control over their phytobeneficial characteristics. We assessed the expression of phytobeneficial genes involved in biocontrol, biostimulation and iron regulation such as, phlD, hcnA, acdS, and iron-small regulatory RNAs prrF1 and prrF2 in Pseudomonas brassicacearum co-cultivated with three phytopathogenic fungi, and two rhizobacteria in the presence or absence of Brassica napus, and in relation to iron availability. We found that the antifungal activity of P. brassicacearum depends mostly on the production of DAPG and not on HCN whose production is suppressed by fungi. We have also shown that the twocompeting bacterial strains modulate the plant growth promotion activity of P. brassicacearum by modifying the expression of phlD, hcnA and acdS according to iron availability. Overall, it allows us to better understand the complexity of the multiple molecular dialogues that take place underground between microorganisms and between plants and its rhizosphere microbiota and to show that synergy in favour of phytobeneficial gene expression may exist between different bacterial species.
Published: 2022

38. TFIIFα interacts with the Topoisomerase VI complex and selectively controls the expression of genes encoding PPR proteins involved in organellar RNA editing in Arabidopsis

Author: Laura Dimnet, Cécile Vriet, Dorine Achard, Cécile Lecampion, Christian Breuer, Ludivine Soubigou-Taconnat, Keiko Sugimoto, Etienne Delannoy, Christophe Laloi, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Luminy Génétique et Biophysique des Plantes (LGBP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Ecologie et biologie des interactions (EBI), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), RIKEN Center for Sustainable Resource Science [Yokohama] (RIKEN CSRS), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Institut des Sciences des Plantes de Paris-Saclay (IPS2 (UMR_9213 / UMR_1403)), and Université d'Évry-Val-d'Essonne (UEVE)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: [SDV]Life Sciences [q-bio]
Abstract: Communication between organelles and the nucleus is referred to as anterograde (nucleus to organelle) and retrograde (organelle to nucleus) signalling. In plants, the pentatricopeptide repeat (PPR) proteins represent a large family of nuclear-encoded proteins that are required for post-transcriptional control of chloroplast and mitochondria gene expression, and hence play a central role in the nuclear anterograde control of organelle genome expression. How PPR gene expression is controlled and regulated by retrograde signals is, however, still unknown. Here, we report a significant role for the general transcription factor TFIIF α-subunit (TFIIFα) in controlling PPR gene expression in Arabidopsis. First, we found that TFIIFα interacts with the BIN4 subunit of the Topoisomerase VI (Topo VI). Transcriptome analysis of TFIIF and Topo VI mutant lines then revealed that many PLS-type PPR genes involved in RNA editing are reciprocally controlled by TFIIF and Topo VI. The misexpression of CLB19 and DYW1 genes in two allelic tfIIfα mutants was associated with editing impairments in their plastid target RNAs rpoA and ndhD, respectively. Interestingly, we also detected a change in NDH activity in tfIIfα plants. We also show that TFIIFα and Topo VI coordinate the expression of NDH subunits encoded by the nuclear and plastid genomes. These results reveal the crucial role of the nuclear TFIIFα and Topo VI complexes in controlling plastid genome expression at multiple levels of regulation, including the particular regulation of PPR gene expression.
Published: 2022

39. Two-dimensional electronic spectroscopy of the Qx to Qy relaxation of chlorophylls a in photosystem II core complex

Author: Stefano Caffarri, Howe-Siang Tan, Thanh Nhut Do, Long Nguyen, Luminy Génétique et Biophysique des Plantes (LGBP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and School of Physical and Mathematical Sciences
Subjects: Chlorophyll, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Light Harvesting System, Chemistry [Science], General Physics and Astronomy, Physical and Theoretical Chemistry
Abstract: Using two-dimensional electronic spectroscopy, we measured the Qx to Qy transfer dynamics of the chlorophyll a (Chl a) manifold in the photosystem II (PSII) monomeric core complex from Arabidopsis thaliana. A PSII monomeric core consists of 35 Chls a and no Chl b, thus allowing for a clear window to study Chl a Qx dynamics in a large pigment-protein complex. Initial excitation in the Qx band results in a transfer to the Qy band in less than 60 fs. Upon the ultrafast transfer, regardless of the excitation frequency within the Qx band, the quasi-transient absorption spectra are very similar. This observation indicates that Chl a’s Qx to Qy transfer is not frequency selective. Using a simple model, we determined that this is not due to the lifetime broadening of the ultrafast transfer but predominantly due to a lack of correlation between the PSII core complex’s Chl a Qx and Qy bands. We suggest the origin to be the intrinsic loss of correlation during the Qx to Qy internal conversion as observed in previous studies of molecular Chl a dissolved in solvents.
Published: 2022

40. Metal crossroads in plants: modulation of nutrient acquisition and root development by essential trace metals

Author: Ricardo Fabiano Hettwer Giehl, Hélène Javot, Alexandra Lešková, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Plant Environmental Physiology and Stress Signaling (PEPSS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Leibniz Institute of Plant Genetics and Crop Plant Research [Gatersleben] (IPK-Gatersleben), and ANR-19-CE13-0007,PHLOWZ,Approche systémique de l'interaction entre les voies de signalisation du Zinc et du Phosphate(2019)
Subjects: Crops, Agricultural, Micronutrient deficiency, Physiology, Chemistry, fungi, food and beverages, Metal toxicity, Plant Science, Root system, Trace Elements, Trace (semiology), Metal, Plant Breeding, Soil, [SDV.BV.AP]Life Sciences [q-bio]/Vegetal Biology/Plant breeding, Nutrient, Metals, visual_art, Environmental chemistry, Soil water, visual_art.visual_art_medium, Trace metal
Abstract: The metals iron, zinc, manganese, copper, molybdenum, and nickel are essential for the growth and development of virtually all plant species. Although these elements are required at relatively low amounts, natural factors and anthropogenic activities can significantly affect their availability in soils, inducing deficiencies or toxicities in plants. Because essential trace metals can shape root systems and interfere with the uptake and signaling mechanisms of other nutrients, the non-optimal availability of any of them can induce multi-element changes in plants. Interference by one essential trace metal with the acquisition of another metal or a non-metal nutrient can occur prior to or during root uptake. Essential trace metals can also indirectly impact the plant’s ability to capture soil nutrients by targeting distinct root developmental programs and hormone-related processes, consequently inducing largely metal-specific changes in root systems. The presence of metal binding domains in many regulatory proteins also enables essential trace metals to coordinate nutrient uptake by acting at high levels in hierarchical signaling cascades. Here, we summarize the known molecular and cellular mechanisms underlying trace metal-dependent modulation of nutrient acquisition and root development, and highlight the importance of considering multi-element interactions to breed crops better adapted to non-optimal trace metal availabilities.
Published: 2022

41. Thiol Reductases in Deinococcus Bacteria and Roles in Stress Tolerance

Author: Arjan De Groot, Pascal REY, Nicolas Rouhier, Laurence Blanchard, Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Interactions Arbres-Microorganismes (IAM), Université de Lorraine (UL)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Protéines de Protection des Végétaux (PPV), and ANR-19-CE12-0010,NOVOREP,Réparation des dommages ou mort cellulaire chez les bactéries exposées aux stress(2019)
Subjects: bacillithiol, Physiology, Clinical Biochemistry, thiol, peroxidase, Cell Biology, thioredoxin, Biochemistry, protein redox status, reductase, bacteria, oxidative stress, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Deinococcus, Molecular Biology, cysteine
Abstract: International audience; Deinococcus species possess remarkable tolerance to extreme environmental conditions that generate oxidative damage to macromolecules. Among enzymes fulfilling key functions in metabolism regulation and stress responses, thiol reductases (TRs) harbour catalytic cysteines modulating the redox status of Cys and Met in partner proteins. We present here a detailed description of Deinococcus TRs regarding gene occurrence, sequence features, and physiological functions that remain poorly characterised in this genus. Two NADPH-dependent thiol-based systems are present in Deinococcus. One involves thioredoxins, disulfide reductases providing electrons to protein partners involved notably in peroxide scavenging or in preserving protein redox status. The other is based on bacillithiol, a low-molecular-weight redox molecule, and bacilliredoxin, which together protect Cys residues against overoxidation. Deinococcus species possess various types of thiol peroxidases whose electron supply depends either on NADPH via thioredoxins or on NADH via lipoylated proteins. Recent data gained on deletion mutants confirmed the importance of TRs in Deinococcus tolerance to oxidative treatments, but additional investigations are needed to delineate the redox network in which they operate, and their precise physiological roles. The large palette of Deinococcus TR representatives very likely constitutes an asset for the maintenance of redox homeostasis in harsh stress conditions.
Published: 2022

42. An insight into the genome of extensively drug-resistant and uropathogenic Citrobacter werkmanii

Author: Shadab Parvez, Shanmugam Mayilraj, Asad U. Khan, Mohamed Barakat, Philippe Ortet, Gurwinder Kaur, Medical Microbiology and Molecular Biology Lab., Interdisciplinary Biotechnology Unit, A.M.U., Aligarh – 202 002, India, Microbial Type Culture Collection & Gene Bank, CSIR- Institute of Microbial Technology, Chandigarh - 160 036, India, Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, Microbiology (medical), 030106 microbiology, Immunology, Virulence, Biology, medicine.disease_cause, Antimicrobial resistance, Genome, Microbiology, beta-Lactamases, NDM-6, 03 medical and health sciences, Two-component system, Citrobacter, 0302 clinical medicine, Antibiotic resistance, Drug Resistance, Multiple, Bacterial, RNA, Ribosomal, 16S, medicine, Immunology and Allergy, 030212 general & internal medicine, Insertion sequence, Escherichia coli, Gene, Citrobacter werkmanii, Genetics, IS30, Uropathogen, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Pathogenicity island, QR1-502, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Pharmaceutical Preparations, rpoS, Multilocus Sequence Typing
Abstract: Objective Carbapenemase-producing bacteria pose a serious public-health threat. This study was performed to understand the emergence and genetic features of NDM-producers in hospital setting. Methods Samples were collected from a tertiary-care hospital. Isolate identification was performed by 16S rRNA sequencing. The genome of Citrobacter werkmanii (AK-8) was sequenced on an Illumina NextSeq 500 platform. Resistance determinants and pathogenicity islands were determined by ResFinder and PathogenFinder, respectively. MLST, two-component systems and transcription factors were identified by P2RP server, whilst variant calling and insertion sequence (IS) elements were determined by Galaxy and ISfinder, respectively. The genome of AK-8 was compared with uropathogenic Escherichia coli strain 536. Results This is the first report on whole-genome analysis of extensively drug-resistant NDM-6-producing uropathogenic C. werkmanii ST-104. Resistance genes for all antibiotics except colistin, fosfomycin, fusidic- acid, nitroimidazole, oxazolidinones, tetracycline and glycopeptides were detected in this strain. Genome analysis of AK-8 led to the identification of the BaeSR two-component system regulating production of multidrug efflux proteins. Virulence was regulated by CpxRA, ZraRS, RstAB, UhpAB, AcrAB, RcsBc and UvrY, whereas Bar–UvrY was found to control carbon metabolism, flagellum biosynthesis and biofilm formation. The AK-8 genome encodes 21 chemoreceptors involved in colonisation and pathogenesis. Fur family transcriptional regulator, cAMP receptor protein and RpoS were found to increase the virulence of AK-8. ntBLAST analysis showed 69.60% genetic identity with E. coli 536 as an adaptive feature for survival. Conclusion The emergence of extensively drug-resistant pathogenic C. werkmanii is alarming and it should not be ignored as commensal.
Published: 2020

43. Iron‐biomineralizing organelle in magnetotactic bacteria: function, synthesis and preservation in ancient rock samples

Author: François P. Mathon, Christopher T. Lefèvre, Vincent Busigny, Caroline L. Monteil, Matthieu Amor, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Geophysical Sciences [Chicago], University of Chicago, Microbiologie Environnementale et Moléculaire (MEM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), ANR-18-CE31-0003,SIGMAG,SIGNATURE DES MAGNETITES PRODUITES PAR LES BACTERIES MAGNETOTACTIQUES : PERSPECTIVES CHIMIQUES ET ISOTOPIQUES(2018), ANR-19-CE01-0005,PHOSTORE,Piégeage du phosphore : contribution des bactéries magnétotactiques dans les zones de transition oxique-anoxique(2019), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), and Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: Greigite, Mineralization (geology), Magnetotactic bacteria, Iron, Microorganism, Geochemistry, Sulfides, Biology, Microbiology, 03 medical and health sciences, chemistry.chemical_compound, Organelle, Magnetite Nanoparticles, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, 030304 developmental biology, Magnetite, 0303 health sciences, Bacteria, 030306 microbiology, Magnetic Phenomena, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, chemistry, Sedimentary rock, Magnetosomes, Function (biology)
Abstract: Magnetotactic bacteria (MTB) are ubiquitous aquatic microorganisms that incorporate iron from their environment to synthesize intracellular nanoparticles of magnetite (Fe3 O4 ) or greigite (Fe3 S4 ) in a genetically controlled manner. Magnetite and greigite magnetic phases allow MTB to swim towards redox transition zones where they thrive. MTB may represent some of the oldest microorganisms capable of synthesizing minerals on Earth and have been proposed to significantly impact the iron biogeochemical cycle by immobilizing soluble iron into crystals that subsequently fossilize in sedimentary rocks. In the present article, we describe the distribution of MTB in the environment and discuss the possible function of the magnetite and greigite nanoparticles. We then provide an overview of the chemical mechanisms leading to iron mineralization in MTB. Finally, we update the methods used for the detection of MTB crystals in sedimentary rocks and present their occurrences in the geological record.
Published: 2020

44. Targeting TOR signaling for enhanced lipid productivity in algae

Author: Marie-Hélène Montané, Laura Prioretti, Frédéric Carrière, Ben Field, Luisana Avilan, Brigitte Gontero, Benoît Menand, Bioénergétique et Ingénierie des Protéines (BIP ), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Luminy Génétique et Biophysique des Plantes (LGBP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-15-CE05-0021,SIGNAUXBIONRJ,Manipulation des voies de signalisation de l'énergie afin d'améliorer la production de .lipides chez les eucaryotes photosynthétiques(2015), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, [SDV]Life Sciences [q-bio], Morpholines, Biochemistry, 03 medical and health sciences, Basic knowledge, Algae, Microalgae, Homeostasis, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Phaeodactylum tricornutum, Protein Kinase Inhibitors, Cholesterol homeostasis, Triglycerides, 030102 biochemistry & molecular biology, biology, TOR Serine-Threonine Kinases, Algal Proteins, General Medicine, Lipid Metabolism, biology.organism_classification, diatom, TOR signaling, Cell biology, 030104 developmental biology, Gene Expression Regulation, Productivity (ecology), Kinase inhibitors, Adipogenesis, Target of rapamycin, Biofuels, Lipogenesis, Signal Transduction
Abstract: International audience; Microalgae can produce large quantities of triacylglycerols (TAGs) and other neutral lipids that are suitable for making biofuels and as feedstocks for green chemistry. However, TAGs accumulate under stress conditions that also stop growth, leading to a trade-off between biomass production and TAG yield. Recently, in the model marine diatom Phaeodactylum tricornutum it was shown that inhibition of the target of rapamycin (TOR) kinase boosts lipid productivity by promoting TAG production without stopping growth. We believe that basic knowledge in this emerging field is required to develop innovative strategies to improve neutral lipid accumulation in oleaginous microalgae. In this minireview, we discuss current research on the TOR signaling pathway with a focus on its control on lipid homeostasis. We first provide an overview of the well characterized roles of TOR in mammalian lipogenesis, adipogenesis and lipolysis. We then present evidence of a role for TOR in controlling TAG accumulation in microalgae, and draw parallels between the situation in animals, plants and microalgae to propose a model of TOR signaling for TAG accumulation in microalgae.
Published: 2020

45. Rhizodeposition efficiency of pearl millet genotypes assessed on a short growing period by carbon isotopes (δ13C and F14C)

Author: Ndour, Papa Mamadou Sitor, Hatté, Christine, Achouak, Wafa, Heulin, Thierry, Cournac, Laurent, Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (UMR Eco&Sols), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Université Mohammed VI Polytechnique [Ben Guerir] (UM6P), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochrononologie Traceurs Archéométrie (GEOTRAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institute of Physics [Gliwice], Silesian University of Technology, Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), This research has been supported by the Agence Nationale de la Recherche (grant no. ANR-17-CE20-0022) and the Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CarbonSeq, DRF impulsion)., Papa Mamadou Sitor Ndour would like to thank the French National Research Institute for Sustainable Development (IRD) and the Make Our Planet Great Again (MOPGA) initiative of the French government for co-funding his postdoctoral fellowship. We thank Oscar Pascal Malou for communicating data on soil texture., and ANR-17-CE20-0022,RootAdapt,Traits racinaires pour l'adaptation du mil au climat futur en Afrique de l'Ouest(2017)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, food and beverages, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract: International audience; Rhizosheath size varies significantly with crop genotype, and root exudation is one among its driving factors. Unravelling the relationships between rhizosheath formation, root exudation and soil carbon dynamics may bring interesting perspectives in terms of crop breeding towards sustainable agriculture. Here we grew four pearl millet (C 4 plant type: δ 13 C of −12.8 ‰, F 14 C = 1.012) inbred lines showing contrasting rhizosheath sizes in a C 3 soil type (organic matter with δ 13 C of −22.3 ‰, F 14 C = 1.045). We sampled the root-adhering soil (RAS) and bulk soil after 28 d of growth under a semi-controlled condition. The soil organic carbon (SOC) content and δ 13 C and F 14 C of soil samples were measured and the plant-derived C amount and C lost / C new ratio in the RAS were calculated. The results showed a significant increase in δ 13 C in the RAS of the four pearl millet lines compared to the control soil, suggesting that this approach was able to detect plant C input into the soil at an early stage of pearl millet growth. The concentration of plant-derived C in the RAS did not vary significantly between pearl millet lines, but the absolute amount of plant-derived C varied significantly when we considered the RAS mass of these different lines. Using a conceptual model and data from the two carbon isotopes' measurements, we evidenced a priming effect for all pearl millet lines. Importantly, the priming effect amplitude (C lost / C new ratio) was higher for the small rhizosheath (low-aggregation) line than for the large rhizosheath (high-aggregation) ones, indicating a better C sequestration potential of the latter.
Published: 2022

46. Plastoquinone homeostasis in plant acclimation to light intensity

Author: Brigitte Ksas, Jean Alric, Stefano Caffarri, Michel Havaux, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Unite Mixte Rech Biol Vegetale & Microbiol Enviro, Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Photosynthèse & Environnement (P&E), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Luminy Génétique et Biophysique des Plantes (LGBP), Plant Environmental Physiology and Stress Signaling (PEPSS), and Financial support from CEA (Radiobiology 2019 program), CNRS (Metaphores 2020–2021 project) and ECCOREV is acknowledged
Subjects: 0106 biological sciences, 0303 health sciences, Light, Plastoquinone, Acclimatization, [SDV]Life Sciences [q-bio], Arabidopsis, food and beverages, Photosystem II Protein Complex, Cell Biology, Plant Science, General Medicine, 01 natural sciences, Biochemistry, Thylakoids, Electron Transport, 03 medical and health sciences, Homeostasis, Photosynthesis, Oxidation-Reduction, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, 010606 plant biology & botany
Abstract: International audience; Arabidopsis plants were grown from seeds at different photon flux densities (PFDs) of white light ranging from 65 to 800 µmol photons m$^{−2}$ s$^{−1}$. Increasing PFD brought about a marked accumulation of plastoquinone (PQ) in leaves. However, the thylakoid photoactive PQ pool, estimated to about 700 pmol mg$^{−1}$ leaf dry weight, was independent of PFD; PQ accumulation in high light mostly occurred in the photochemically non-active pool (plastoglobules, chloroplast envelopes) which represented up to 75% of total PQ. The amounts of PSII reaction center (on a leaf dry weight basis) also were little affected by PFD during growth, leading to a constant PQ/PSII ratio at all PFDs. Boosting PQ biosynthesis by overexpression of a solanesyl diphosphate-synthesizing enzyme strongly enhanced the PQ levels, particularly at high PFDs. Again, this accumulation occurred exclusively in the non-photoactive PQ pool. Mutational suppression of the plastoglobular ABC1K1 kinase led to a selective reduction of the thylakoid PQ pool size to ca. 400 pmol mg$^{−1}$ in a large range of PFDs, which was associated with a restriction of the photosynthetic electron flow. Our results show that photosynthetic acclimation to light intensity does not involve modulation of the thylakoid PQ pool size or the amounts of PSII reaction centers. There appears to be a fixed amount of PQ molecules for optimal interaction with PSII and efficient photosynthesis, with the extra PQ molecules being stored outside the thylakoid membranes, implying a tight regulation of PQ distribution within the chloroplasts.
Published: 2022

47. Coral symbionts evolved a functional polycistronic flavodiiron gene

Author: Kenya Tanaka, Minoru Kumazawa, Shuji Nakanishi, Kentaro Ifuku, Eiichi Shoguchi, Adrien Burlacot, Ginga Shimakawa, Yufen Che, Osaka University [Osaka], Okinawa Institute of Science and Technology Graduate University (OIST), Environnement, Bioénergie, Microalgues et Plantes (EBMP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Kyoto University
Subjects: Cyanobacteria, Genetics, [SDV]Life Sciences [q-bio], Dinoflagellate, Sequence alignment, Cell Biology, Plant Science, General Medicine, Biology, biology.organism_classification, Biochemistry, Algae, Coding region, Green algae, Plastid, Gene
Abstract: International audience; Photosynthesis in cyanobacteria, green algae, and basal land plants is protected against excess reducing pressure on the photosynthetic chain by flavodiiron proteins (FLV) that dissipate photosynthetic electrons by reducing O$_2$. In these organisms, the genes encoding FLV are always conserved in the form of a pair of two-type isozymes (FLVA and FLVB) that are believed to function in O$_2$ photo-reduction as a heterodimer. While coral symbionts (dinoflagellates of the family Symbiodiniaceae) are the only algae to harbor FLV in photosynthetic red plastid lineage, only one gene is found in transcriptomes and its role and activity remain unknown. Here, we characterized the FLV genes in Symbiodiniaceae and found that its coding region is composed of tandemly repeated FLV sequences. By measuring the O$_2$-dependent electron flow and P700 oxidation, we suggest that this atypical FLV is active in vivo. Based on the amino-acid sequence alignment and the phylogenetic analysis, we conclude that in coral symbionts, the gene pair for FLVA and FLVB have been fused to construct one coding region for a hybrid enzyme, which presumably occurred when or after both genes were inherited from basal green algae to the dinoflagellate. Immunodetection suggested the FLV polypeptide to be cleaved by a post-translational mechanism, adding it to the rare cases of polycistronic genes in eukaryotes. Our results demonstrate that FLV are active in coral symbionts with genomic arrangement that is unique to these species. The implication of these unique features on their symbiotic living environment is discussed.
Published: 2022

48. Interactions Between Carbon Metabolism and Photosynthetic Electron Transport in a Chlamydomonas reinhardtii Mutant Without CO2 Fixation by RuBisCO

Author: Maureen Saint-Sorny, Pawel Brzezowski, Stéphanie Arrivault, Jean Alric, Xenie Johnson, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Biologie végétale et microbiologie environnementale - UMR7265 (BVME), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Max Planck Institute of Molecular Plant Physiology (MPI-MP), and Max-Planck-Gesellschaft
Subjects: [SDV]Life Sciences [q-bio], Plant Science
Abstract: A Chlamydomonas reinhardtii RuBisCO-less mutant, ΔrbcL, was used to study carbohydrate metabolism without fixation of atmospheric carbon. The regulatory mechanism(s) that control linear electron flow, known as “photosynthetic control,” are amplified in ΔrbcL at the onset of illumination. With the aim to understand the metabolites that control this regulatory response, we have correlated the kinetics of primary carbon metabolites to chlorophyll fluorescence induction curves. We identify that ΔrbcL in the absence of acetate generates adenosine triphosphate (ATP) via photosynthetic electron transfer reactions. Also, metabolites of the Calvin Benson Bassham (CBB) cycle are responsive to the light. Indeed, ribulose 1,5-bisphosphate (RuBP), the last intermediate before carboxylation by Ribulose-1,5-bisphosphate carboxylase-oxygenase, accumulates significantly with time, and CBB cycle intermediates for RuBP regeneration, dihydroxyacetone phosphate (DHAP), pentose phosphates and ribose-5-phosphate (R5P) are rapidly accumulated in the first seconds of illumination, then consumed, showing that although the CBB is blocked, these enzymes are still transiently active. In opposition, in the presence of acetate, consumption of CBB cycle intermediates is strongly diminished, suggesting that the link between light and primary carbon metabolism is almost lost. Phosphorylated hexoses and starch accumulate significantly. We show that acetate uptake results in heterotrophic metabolism dominating phototrophic metabolism, with glyoxylate and tricarboxylic acid (TCA) cycle intermediates being the most highly represented metabolites, specifically succinate and malate. These findings allow us to hypothesize which metabolites and metabolic pathways are relevant to the upregulation of processes like cyclic electron flow that are implicated in photosynthetic control mechanisms.
Published: 2022

49. Direct inhibition of phosphate transport by immune signaling in Arabidopsis

Author: Dindas, Julian, DeFalco, Thomas A, Yu, Gang, Zhang, Lu, David, Pascale, Bjornson, Marta, Thibaud, Marie-Christine, Custódio, Valéria, Castrillo, Gabriel, Nussaume, Laurent, Macho, Alberto P, Zipfel, Cyril, University of Zurich, Zipfel, Cyril, Zurich Basel Plant Science Center, Universität Zürich [Zürich] = University of Zurich (UZH)-University of Basel (Unibas), The Sainsbury Laboratory [Norwich] (TSL), National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences [Changchun Branch] (CAS), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Plant Environmental Physiology and Stress Signaling (PEPSS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), University of Nottingham, UK (UON), European Project: 309858,EC:FP7:ERC,ERC-2012-StG_20111109,PHOSPHINNATE(2012), European Project: 773153,IMMUNO-PEPTALK, Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Signalisation de l'Adaptation des Végétaux à l'Environnement (SAVE), and Biologie végétale et microbiologie environnementale - UMR7265 (BVME)
Subjects: 0106 biological sciences, kinase, [SDV]Life Sciences [q-bio], Arabidopsis, Genetics and Molecular Biology, 1100 General Agricultural and Biological Sciences, 580 Plants (Botany), 01 natural sciences, Plant Roots, General Biochemistry, Genetics and Molecular Biology, Phosphates, 03 medical and health sciences, 10126 Department of Plant and Microbial Biology, Gene Expression Regulation, Plant, 1300 General Biochemistry, Genetics and Molecular Biology, Report, root microbiome, Phosphate Transport Proteins, Gene Regulatory Networks, 10211 Zurich-Basel Plant Science Center, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, phosphate, 2. Zero hunger, 0303 health sciences, Arabidopsis Proteins, 2800 General Neuroscience, PHT1, 15. Life on land, electrophysiology, General Biochemistry, plant immunity, General Agricultural and Biological Sciences, 010606 plant biology & botany
Abstract: Summary Soil availability of inorganic ortho-phosphate (PO43−, Pi) is a key determinant of plant growth and fitness.1 Plants regulate the capacity of their roots to take up inorganic phosphate by adapting the abundance of H+-coupled phosphate transporters of the PHOSPHATE TRANSPORTER 1 (PHT1) family2 at the plasma membrane (PM) through transcriptional and post-translational changes driven by the genetic network of the phosphate starvation response (PSR).3, 4, 5, 6, 7, 8 Increasing evidence also shows that plants integrate immune responses to alleviate phosphate starvation stress through the association with beneficial microbes.9, 10, 11 Whether and how such phosphate transport is regulated upon activation of immune responses is yet uncharacterized. To address this question, we first developed quantitative assays based on changes in the electrical PM potential to measure active Pi transport in roots in real time. By inserting micro-electrodes into bulging root hairs, we were able to determine key characteristics of phosphate transport in intact Arabidopsis thaliana (hereafter Arabidopsis) seedlings. The fast Pi-induced depolarization observed was dependent on the activity of the major phosphate transporter PHT1;4. Notably, we observed that this PHT1;4-mediated phosphate uptake is repressed upon activation of pattern-triggered immunity. This inhibition depended on the receptor-like cytoplasmic kinases BOTRYTIS-INDUCED KINASE 1 (BIK1) and PBS1-LIKE KINASE 1 (PBL1), which both phosphorylated PHT1;4. As a corollary to this negative regulation of phosphate transport by immune signaling, we found that PHT1;4-mediated phosphate uptake normally negatively regulates anti-bacterial immunity in roots. Collectively, our results reveal a mechanism linking plant immunity and phosphate homeostasis, with BIK1/PBL1 providing a molecular integration point between these two important pathways., Highlights • Real-time, PHT1-mediated Pi transport can be measured in roots via PM depolarization • Immune activation represses Pi transport in a BIK1/PBL1-dependent manner • PHT1s are direct substrates of BIK1 and PBL1 • Pi uptake modulates anti-bacterial immunity and the root microbiome, Phosphate (Pi) is a crucial determinant of plant growth and fitness. Dindas, DeFalco, et al. show that immune activation in roots actively represses Pi uptake. This inhibition is achieved via direct phosphorylation of key Pi transporters by the central immune kinases BIK1 and PBL1, which leads to increased anti-bacterial defense.
Published: 2022

50. Implications of carbon catabolite repression for plant–microbe interactions

Author: Theophile Franzino, Hasna Boubakri, Tomislav Cernava, Danis Abrouk, Wafa Achouak, Sylvie Reverchon, William Nasser, Feth el Zahar Haichar, Microbiologie, adaptation et pathogénie (MAP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Chromatine et Régulation de la Pathogénie bactérienne (CRP), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Graz University of Technology [Graz] (TU Graz), Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and ANR-18-CE32-0005,DIORE,Régulation de la dénitrification par la nature des exsudats racinaires(2018)
Subjects: Catabolite Repression, Bacteria, integumentary system, fungi, Fungi, Cell Biology, Plant Science, carbon catabolite repression, Biochemistry, CCR, Carbon, carbon utilization, [SDE]Environmental Sciences, rhizosphere, Molecular Biology, substrate-use preferences, Biotechnology, plant-microbe interaction
Abstract: International audience; Carbon catabolite repression (CCR) plays a key role in many physiological and adaptive responses in a broad range of microorganisms that are commonly associated with eukaryotic hosts. When a mixture of different carbon sources is available, CCR, a global regulatory mechanism, inhibits the expression and activity of cellular processes associated with utilization of secondary carbon sources in the presence of the preferred carbon source. CCR is known to be executed by completely different mechanisms in different bacteria, yeast, and fungi. In addition to regulating catabolic genes, CCR also appears to play a key role in the expression of genes involved in plant-microbe interactions. Here, we present a detailed overview of CCR mechanisms in various bacteria. We highlight the role of CCR in beneficial as well as deleterious plant-microbe interactions based on the available literature. In addition, we explore the global distribution of known regulatory mechanisms within bacterial genomes retrieved from public repositories and within metatranscriptomes obtained from different plant rhizospheres. By integrating the available literature and performing targeted meta-analyses, we argue that CCR-regulated substrate use preferences of microorganisms should be considered an important trait involved in prevailing plant-microbe interactions.
Published: 2022

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Journal

Database

Publisher

893 results on '"Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA))"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources