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1. Diatom phytochromes integrate the entire visible light spectra for photosensing in marine environments

Author

Carole Duchêne, Jean-Pierre Bouly, Juan José Pierella Karlusich, Julien Sellés, Benjamin Bailleul, Chris Bowler, Maurizio Ribera d’Alcalà, Angela Falciatore, Marianne Jaubert, Biologie du chloroplaste et perception de la lumière chez les micro-algues, Institut de biologie physico-chimique (IBPC (FR_550)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-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), Stazione Zoologica Anton Dohrn (SZN), GBMF4981.01KR1661/20-1MITI interdisciplinary programFondation Bettencourt-Schueller (Coups d’élan pour la recherche francaise-2018), ANR-11-LABX-0011,DYNAMO,Dynamique des membranes transductrices d'énergie : biogénèse et organisation supramoléculaire.(2011), ANR-20-CE20-0024,CLIMA-CLOCK,Photopériodisme chez des microalgues ubiquistes modèles du phytoplancton marin : mécanismes moléculaires et sensibilité à l'augmentation de la température de l'océan(2020), ANR-11-BTBR-0008,OCEANOMICS,Biotechnologies et bioressources pour la valorisation des écosystèmes marins planctoniques(2011), ANR-19-CE20-0020,BrownCut,Elucidation des gènes spécifiques de la photosynthèse chez les diatomées(2019), ANR-21-CE02-0021,Dim,Croissance des micro-algues à très faibles lumières sous la banquise arctique à la sortie de la nuit polaire, et rôle dans l'inoculation du bloom printanier(2021), Jaubert, Marianne, Dynamique des membranes transductrices d'énergie : biogénèse et organisation supramoléculaire. - - DYNAMO2011 - ANR-11-LABX-0011 - LABX - VALID, Photopériodisme chez des microalgues ubiquistes modèles du phytoplancton marin : mécanismes moléculaires et sensibilité à l'augmentation de la température de l'océan - - CLIMA-CLOCK2020 - ANR-20-CE20-0024 - AAPG2020 - VALID, Biotech - Bioressources - Biotechnologies et bioressources pour la valorisation des écosystèmes marins planctoniques - - OCEANOMICS2011 - ANR-11-BTBR-0008 - BTBR - VALID, Elucidation des gènes spécifiques de la photosynthèse chez les diatomées - - BrownCut2019 - ANR-19-CE20-0020 - AAPG2019 - VALID, and Croissance des micro-algues à très faibles lumières sous la banquise arctique à la sortie de la nuit polaire, et rôle dans l'inoculation du bloom printanier - - Dim2021 - ANR-21-CE02-0021 - AAPG2021 - VALID

Subjects
[SDV] Life Sciences [q-bio], [SDV]Life Sciences [q-bio]
Abstract

Aquatic life is strongly structured by light gradients, with gradual decrease in light intensity and differential attenuation of sunlight wavelengths with depth. How phytoplankton perceive these variations is unknown. By providing the firstin vivoquantitative assessment of the action of marine diatom phytochrome photoreceptors (DPH), we show that they efficiently trigger photoreversible responses across the entire light spectrum, unlike current models of phytochrome photosensing. The distribution and activity of DPHs in the environment indicate that they are extremely sensitive detectors of spectral light variations related to depth and optical properties of the water column in temperate and polar oceans, revealing a completely novel view of how light is perceived in the marine environment.

Published
2023

2. The multiple routes of photosynthetic electron transfer in Chlamydomonas reinhardtii

Author

Dany Croteau, Jean Alric, Benjamin Bailleul, Biologie du chloroplaste et perception de la lumière chez les micro-algues, Institut de biologie physico-chimique (IBPC (FR_550)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-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), Francis-André Wollman, Arthur Grossman, and European Project: 715579,PhotoPHYTOMICS

Subjects
PTOX, photosynthesis, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, flavodiiron proteins, Chlamydomonas, Alternative electron flows, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], Cyclic Electron flow, Mehler
Abstract

International audience; Like all organisms performing oxygenic photosynthesis, Chlamydomonas captures light energy in two photochemical steps to drive linear electron flow from water to NADPH and to produce ATP. However, this process alone is not sufficient to drive CO2 fixation in the Calvin–Benson cycle and to respond to environmental and metabolic constraints, for example, light availability or metabolic needs in term of ATP and NADPH. A complex network of alternative electron flows, comprises cyclic electron flow around photosystem I and various water-to-water cycles that utilize O2 as an alternative electron acceptor, provide an additional degree of freedom to face this challenge. The present chapter describes the various alternative routes of photosynthetic electron transfer in Chlamydomonas, describes how they are coordinated for optimization of photosynthesis and gives a retrospective on the early physiology work on those alternative electron flows among model photosynthetic organisms.

Published
2023

3. Photosynthetic Light Reactions in Diatoms. II. The Dynamic Regulation of the Various Light Reactions

Author

Bernard Lepetit, Douglas A. Campbell, Johann Lavaud, Claudia Büchel, Reimund Goss, Benjamin Bailleul, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Biologie du chloroplaste et perception de la lumière chez les micro-algues, Institut de biologie physico-chimique (IBPC (FR_550)), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV.EE]Life Sciences [q-bio]/Ecology, environment, NPQ, photosynthesis, photoinhibition, Photosystem II repair, xanthophyll cycle, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Lhcx, alternative electron flow, diatoms
Abstract

International audience; Photosynthesis in diatoms is performed using the same basic modules as cyanobacteria and plants. It can be regulated on multiple levels depending on the environmental cues, allowing diatoms to adjust their photosynthetic light reaction towards optimum whilst at the same time minimizing photodamage induced by light. In recent years, tremendous progress has been gained in understanding these acclimation processes, revealing several diatom-specific features. In this chapter, we trace several paths through the photosynthetic electron transport chain to optimize photosynthesis. We review how diatoms repair photoinactivated reaction centers and which mechanisms they have to preempt photodamage. Finally, photoprotection is set in an ecophysiological context, highlighting differences in photoprotection of diatoms from different habitats.

Published
2022

4. Finding Adapted Quinones for Harvesting Electrons from Photosynthetic Algae Suspensions

Author

Luca Alessandro Perego, Benjamin Bailleul, Marc Arderiu Romero, Louis Escudero, Frédéric Lemaître, Adnan Sayegh, Jérôme Delacotte, Manon Guille-Collignon, Laurence Grimaud, Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des biomolécules (LBM UMR 7203), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Département de Chimie - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Chimie Moléculaire de Paris Centre (FR 2769), Institut de Chimie du CNRS (INC)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM), Biologie du chloroplaste et perception de la lumière chez les micro-algues, Institut de biologie physico-chimique (IBPC (FR_550)), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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)-École normale supérieure - Paris (ENS-PSL), Chimie Moléculaire de Paris Centre (FR 2769), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département de Chimie - ENS Paris, 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), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and HAL-SU, Gestionnaire

Subjects
Photocurrent, 0303 health sciences, quinones, photosynthesis, biology, Chemistry, Electron, Chlamydomonas reinhardtii algae, 010402 general chemistry, biology.organism_classification, Electrochemistry, Photochemistry, Photosynthesis, photocurrent, 01 natural sciences, Catalysis, 0104 chemical sciences, 03 medical and health sciences, Algae, electrochemistry, [CHIM] Chemical Sciences, [CHIM]Chemical Sciences, 030304 developmental biology
Abstract

International audience; Among all the chemical and biotechnological strategies implemented to extract energy from oxygenic photosynthesis, several concern the use of intact photosynthetic organisms (algae, cyanobacteria…). This means rerouting (fully or partially) the electron flow from the photosynthetic chain to an outer collecting electrode thus generating a photocurrent. While diverting photosynthetic electrons from living biological systems is an encouraging approach, this strategy is limited by the need to use an electron shuttle. Redox mediators that are able to interact with an embedded photosynthetic chain are rather scarce. In this respect, exogenous quinones are the most frequently used. Unfortunately, some of them also act as poisoning agents within relatively long timeframes. It thus raises the question of the best quinone. In this work, we use a previously reported electrochemical device to analyze the performance of different quinones. Photocurrents (maximum photocurrent, stability) were measured from suspensions of Chlamydomonas reinhardtii algae/quinones by chronoamperometry and compared to parameters like quinone redox potentials or cytotoxic concentration. From these results, several quinones were synthesized and analyzed in order to find the best compromise between bioelectricity production and toxicity.

Published
2021

5. The fine-tuning of NPQ in diatoms relies on the regulation of both xanthophyll cycle enzymes

Author

Lamia Chafai, Benjamin Bailleul, Lander Blommaert, Biologie du chloroplaste et perception de la lumière chez les micro-algues, Institut de biologie physico-chimique (IBPC (FR_550)), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Royal Netherlands Institute for Sea Research (NIOZ)

Subjects
0106 biological sciences, 0301 basic medicine, Light, Physiology, Science, Biophysics, Xanthophylls, Photosynthesis, 01 natural sciences, Biochemistry, Article, Fluorescence, 03 medical and health sciences, chemistry.chemical_compound, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Phaeodactylum tricornutum, Electrochemical gradient, chemistry.chemical_classification, Diatoms, Multidisciplinary, Quenching (fluorescence), biology, Chlorophyll A, Diadinoxanthin, Diatoxanthin, biology.organism_classification, Enzymes, Kinetics, 030104 developmental biology, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, chemistry, Photoprotection, Xanthophyll, Medicine, Epoxy Compounds, Plant sciences, 010606 plant biology & botany
Abstract

Diatoms possess an efficient mechanism to dissipate photons as heat in conditions of excess light, which is visualized as the Non-Photochemical Quenching of chlorophyll a fluorescence (NPQ). In most diatom species, NPQ is proportional to the concentration of the xanthophyll cycle pigment diatoxanthin formed from diadinoxanthin by the diadinoxanthin de-epoxidase enzyme. The reverse reaction is performed by the diatoxanthin epoxidase. Despite the xanthophyll cycle’s central role in photoprotection, its regulation is not yet well understood. The proportionality between diatoxanthin and NPQ allowed us to calculate the activity of both xanthophyll cycle enzymes in the model diatom Phaeodactylum tricornutum from NPQ kinetics. From there, we explored the light-dependency of the activity of both enzymes. Our results demonstrate that a tight regulation of both enzymes is key to fine-tune NPQ: (i) the rate constant of diadinoxanthin de-epoxidation is low under a light-limiting regime but increases as photosynthesis saturates, probably due to the thylakoidal proton gradient ΔpH (ii) the rate constant of diatoxanthin epoxidation exhibits an optimum under low light and decreases in the dark due to an insufficiency of the co-factor NADPH as well as in higher light through an as yet unresolved inhibition mechanism, that is unlikely to be related to the ΔpH. We observed that the suppression of NPQ by an uncoupler was due to an accelerated diatoxanthin epoxidation enzyme rather than to the usually hypothesized inhibition of the diadinoxanthin de-epoxidation enzyme.

Published
2021

6. Diatom Molecular Research Comes of Age: Model Species for Studying Phytoplankton Biology and Diversity

Author

Angela Falciatore, Jean-Pierre Bouly, Benjamin Bailleul, Marianne Jaubert, Thomas Mock, Biologie du chloroplaste et perception de la lumière chez les micro-algues, Institut de biologie physico-chimique (IBPC (FR_550)), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Biologie Computationnelle et Quantitative = Laboratory of Computational and Quantitative Biology (LCQB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Paris Seine (IBPS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-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), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), School of Environmental Sciences [Norwich], and University of East Anglia [Norwich] (UEA)

Subjects
0106 biological sciences, 0301 basic medicine, [SDV]Life Sciences [q-bio], Thalassiosira pseudonana, Biodiversity, Context (language use), Genomics, Plant Science, Review, 01 natural sciences, Models, Biological, 03 medical and health sciences, Algae, Phylogenetics, 14. Life underwater, Phaeodactylum tricornutum, Phylogeny, ComputingMilieux_MISCELLANEOUS, Diatoms, biology, Ecology, fungi, Cell Biology, biology.organism_classification, 030104 developmental biology, Diatom, Phytoplankton, 010606 plant biology & botany
Abstract

International audience; Diatoms are the world's most diverse group of algae, comprising at least 100,000 species. Contributing ;20% of annual global carbon fixation, they underpin major aquatic food webs and drive global biogeochemical cycles. Over the past two decades, Thalassiosira pseudonana and Phaeodactylum tricornutum have become the most important model systems for diatom molecular research, ranging from cell biology to ecophysiology, due to their rapid growth rates, small genomes, and the cumulative wealth of associated genetic resources. To explore the evolutionary divergence of diatoms, additional model species are emerging, such as Fragilariopsis cylindrus and Pseudo-nitzschia multistriata. Here, we describe how functional genomics and reverse genetics have contributed to our understanding of this important class of microalgae in the context of evolution, cell biology, and metabolic adaptations. Our review will also highlight promising areas of investigation into the diversity of these photosynthetic organisms, including the discovery of new molecular pathways governing the life of secondary plastid-bearing organisms in aquatic environments.

Published
2020

7. Maximal cyclic electron flow rate is independent of PGRL1 in Chlamydomonas

Author

Wojciech J. Nawrocki, F.-A. Wollman, Fabrice Rappaport, Benjamin Bailleul, Pierre Joliot, Pierre Cardol, Physiologie membranaire et moléculaire du chloroplaste (PMMC), Sorbonne Université (SU)-Institut de biologie physico-chimique (IBPC (FR_550)), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Liège, Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique (CNRS), Collège de France (CdF (institution)), Biologie du chloroplaste et perception de la lumière chez les micro-algues, Institut de biologie physico-chimique (IBPC (FR_550)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and European Project: 682580,H2020,ERC-2015-CoG,BEAL(2016)

Subjects
0106 biological sciences, 0301 basic medicine, animal structures, photosystem I, Biophysics, Chlamydomonas reinhardtii, Photosystem I, Photosynthesis, 01 natural sciences, Biochemistry, Redox, Electron Transport, 03 medical and health sciences, Oxidoreductase, [CHIM]Chemical Sciences, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, biology, Chemistry, Cytochrome b6f complex, Chlamydomonas, Wild type, Membrane Proteins, anoxia, Cell Biology, biology.organism_classification, cyclic electron flow, 030104 developmental biology, embryonic structures, cytochrome b6f, Oxidation-Reduction, 010606 plant biology & botany
Abstract

International audience; Cyclic electron flow (CEF) is defined as a return of the reductants from the acceptor side of Photosystem I (PSI) to the pool of its donors via the cytochrome b6f. It is described to be complementary to the linear electron flow and essential for photosynthesis. However, despite many efforts aimed to characterize CEF, its pathway and its regulation modes remain equivocal, and its physiological significance is still not clear. Here we use novel spectroscopic to measure the rate of CEF at the onset of light in the green alga Chlamydomonas reinhardtii. The initial redox state of the photosynthetic chain or the oxygen concentration do not modify the initial maximal rate of CEF (60 electrons per second per PSI) but rather strongly influence its duration. Neither the maximal rate nor the duration of CEF are different in the pgrl1 mutant compared to the wild type, disqualifying PGRL1 as the ferredoxin-plastoquinone reductase involved in the CEF mechanism.

Published
2019

8. The mechanism of cyclic electron flow

Author

Pierre Cardol, Wojciech J. Nawrocki, Pierre Joliot, F.-A. Wollman, Fabrice Rappaport, Daniel Picot, Benjamin Bailleul, Physiologie membranaire et moléculaire du chloroplaste (PMMC), Sorbonne Université (SU)-Institut de biologie physico-chimique (IBPC (FR_550)), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Physico-chimie moléculaire des membranes biologiques (PCMMB), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université de Liège, Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique (CNRS), Collège de France (CdF (institution)), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
0106 biological sciences, 0301 basic medicine, Chloroplasts, Biophysics, Plastoquinone, Photosynthesis, Photosystem I, 01 natural sciences, Biochemistry, Electron Transport, 03 medical and health sciences, Electron transfer, chemistry.chemical_compound, Adenosine Triphosphate, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, ComputingMilieux_MISCELLANEOUS, Photosystem I Protein Complex, Mechanism (biology), Chemistry, Photosystem II Protein Complex, Cell Biology, Chloroplast, Kinetics, 030104 developmental biology, Photoprotection, Electron flow, 010606 plant biology & botany
Abstract

Apart from the canonical light-driven linear electron flow (LEF) from water to CO2, numerous regulatory and alternative electron transfer pathways exist in chloroplasts. One of them is the cyclic electron flow around Photosystem I (CEF), contributing to photoprotection of both Photosystem I and II (PSI, PSII) and supplying extra ATP to fix atmospheric carbon. Nonetheless, CEF remains an enigma in the field of functional photosynthesis as we lack understanding of its pathway. Here, we address the discrepancies between functional and genetic/biochemical data in the literature and formulate novel hypotheses about the pathway and regulation of CEF based on recent structural and kinetic information.

Published
2019

9. Energetic coupling between plastids and mitochondria drives CO2 assimilation in diatoms

Author

Judit Prihoda, Fabrice Rappaport, Denis Falconet, Stefano Santabarbara, Pierre Joliot, Benjamin Bailleul, Atsuko Tanaka, Pierre Cardol, Richard Bligny, Omer Murik, Chris Bowler, Paul G. Falkowski, Serena Flori, Dimitris Petroutsos, Leila Tirichine, Nicolas Berne, Anja Krieger-Liszkay, Giovanni Finazzi, Valeria Villanova, Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), 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 Paris), 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), Physiologie membranaire et moléculaire du chloroplaste (PMMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institute of Marine and Coastal Sciences, Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Génétique et Physiologie des Microalgues, Université de Liège, Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Fermentalg, Serv Bioenerget Biol Struct & Mécanisme, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Istituto di Biofisica, Consiglio Nazionale delle Ricerch, Collège de France (CdF (institution)), Region Rhone-Alpes (Cible project)- Marie Curie Initial Training Network Accliphot (FP7-PEPOPLE-2012-ITN, 316427)- CNRS Defi (ENRS 2013)- CEA Bioenergies program- Belgian Fonds de la Recherche Scientifique- Incentive Grant for Scientific Research F 4520- COSI ITN project, ANR-12-BIME-0005,DiaDomOil,Domestication des diatomées pour la production de biocarburants(2012), ANR-09-BLAN-0139,PhytAdapt,Adaptation du phytoplancton(2009), ANR-11-LABX-0011,DYNAMO,Dynamique des membranes transductrices d'énergie : biogénèse et organisation supramoléculaire.(2011), ANR-11-IDEX-0001,Amidex,INITIATIVE D'EXCELLENCE AIX MARSEILLE UNIVERSITE(2011), ANR-10-IDEX-0001,PSL,Paris Sciences et Lettres(2010), European Project: 294823,EC:FP7:ERC,ERC-2011-ADG_20110310,DIATOMITE(2012), European Project: 287589,EC:FP7:KBBE,FP7-OCEAN-2011,MICRO B3(2012), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-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)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), ANR: NT09_567009,Phytadapt,Phytadapt, ANR-11-LABX-0011/11-LABX-0011,DYNAMO,Dynamique des membranes transductrices d'énergie : biogénèse et organisation supramoléculaire.(2011), ANR: ANR-11-IDEX-0001-02,ANR-11-IDEX-0001-02, ANR-10-IDEX-0001-02/10-LABX-0054,MEMOLIFE,Memory in living systems: an integrated approach(2010), Institut de biologie de l'ENS Paris (IBENS), 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), Université de Liège, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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), Bailleul B., Berne N., Murik O., Petroutsos D., Prihoda J., Tanaka A., Villanova V., Bligny R., Flori S., Falconet D., Krieger-Liszkay A., Santabarbara S., Rappaport F., Joliot P., Tirichine L., Falkowski P.G., Cardol P., Bowler C., Finazzi G., and Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris

Subjects
Aquatic Organisms, chemistry.chemical_compound, Adenosine Triphosphate, Settore BIO/04 - Fisiologia Vegetale, CYCLIC ELECTRON FLOW, Plastids, Photosynthesis, PHAEODACTYLUM-TRICORNUTUM, Plant Proteins, chemistry.chemical_classification, Multidisciplinary, microalgae, Respiration, Carbon fixation, Energetic interactions, Proton-Motive Force, Mitochondria, metabolic mutant, Phenotype, ATP/NADPH ratio, OXYGEN PHOTOREDUCTION, Carbon dioxide, Oxidoreductases, Oxidation-Reduction, Ocean, Oceans and Seas, Electron flow, Marine eukaryotes, Biology, CHLAMYDOMONAS-REINHARDTII, Carbon cycle, Carbon Cycle, Mitochondrial Proteins, Energetic exchanges, Botany, Organic matter, Ecosystem, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, 14. Life underwater, Plastid, Diatoms, Chemiosmosis, fungi, ECS, Carbon Dioxide, chemistry, 13. Climate action, NADP
Abstract

International audience; Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate by absorbing carbon dioxide from the atmosphere, sequestering it via the biological carbon pump and ultimately burying organic carbon in the lithosphere. The proportion of planetary primary production by diatoms in the modern oceans is roughly equivalent to that of terrestrial rainforests. In photosynthesis, the efficient conversion of carbon dioxide into organic matter requires a tight control of the ATP/NADPH ratio which, in other photosynthetic organisms, relies principally on a range of plastid-localized ATP generating processes. Here we show that diatoms regulate ATP/NADPH through extensive energetic exchanges between plastids and mitochondria. This interaction comprises the re-routing of reducing power generated in the plastid towards mitochondria and the import of mitochondrial ATP into the plastid, and is mandatory for optimized carbon fixation and growth. We propose that the process may have contributed to the ecological success of diatoms in the ocean.

Published
2015

10. An atypical member of the light-harvesting complex stress-related protein family modulates diatom responses to light

Author

Chris Bowler, Benjamin Bailleul, Sacha Coesel, Alessandra Rogato, Alessandra De Martino, Pierre Cardol, Angela Falciatore, Giovanni Finazzi, 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), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), 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 Paris), 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), Laboratory of Ecology and Evolution of Plankton, Stazione Zoologica Anton Dohrn (SZN), Génomique des microorganismes, Laboratoire de Génétique des Microorganismes, Université de Liège, Laboratoire de physiologie cellulaire végétale (LPCV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-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), Génomique des Microorganismes (LGM), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
0106 biological sciences, Chlorophyll, llight acclimation, MESH: Light-Harvesting Protein Complexes, Protein family, Light, Light-Harvesting Protein Complexes, Biology, Photosynthesis, 01 natural sciences, Phaeodactylum tricornutum, LHCX, Light-harvesting complex, 03 medical and health sciences, chemistry.chemical_compound, stress, Botany, MESH: Gene Silencing, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Gene Silencing, photoresponse, 030304 developmental biology, Diatoms, 0303 health sciences, light harvesting complex, Multidisciplinary, photosynthesis, fungi, Biological Sciences, biology.organism_classification, MESH: Gene Knockdown Techniques, diatom, MESH: Light, Cell biology, Oxygen, Diatom, chemistry, Gene Knockdown Techniques, phytoplankton, gene expression, Green algae, MESH: Chlorophyll, Function (biology), MESH: Diatoms, MESH: Oxygen, 010606 plant biology & botany
Abstract

Diatoms are prominent phytoplanktonic organisms that contribute around 40% of carbon assimilation in the oceans. They grow and perform optimally in variable environments, being able to cope with unpredictable changes in the amount and quality of light. The molecular mechanisms regulating diatom light responses are, however, still obscure. Using knockdown Phaeodactylum tricornutum transgenic lines, we reveal the key function of a member of the light-harvesting complex stress-related (LHCSR) protein family, denoted LHCX1, in modulation of excess light energy dissipation. In contrast to green algae, this gene is already maximally expressed in nonstressful light conditions and encodes a protein required for efficient light responses and growth. LHCX1 also influences natural variability in photoresponse, as evidenced in ecotypes isolated from different latitudes that display different LHCX1 protein levels. We conclude, therefore, that this gene plays a pivotal role in managing light responses in diatoms.

Published
2010

11. The diatom plastid : energetic center and target of allelopathic interactions

Author

Peltekis, Alexandra, Biologie du chloroplaste et perception de la lumière chez les micro-algues, Institut de biologie physico-chimique (IBPC (FR_550)), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, Francis-André Wollman, Benjamin Bailleul, and STAR, ABES

Subjects
Diatomées, Spectroscopie, [SDV.EE.IEO] Life Sciences [q-bio]/Ecology, environment/Symbiosis, [SDV.MP.PRO] Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Amphidinols, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Microalgae, Alkyl-quinolones, Bactéries, Allélopathie, Photosynthesis, Photosynthèse, Dinoflagellés, Allelopathy, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract

One of the major forces that shape the dynamics and structure of phytoplankton communities is the direct inhibition of the metabolism of competitors thanks to the use of secondary metabolites. But our understanding of this phenomenon, called allelopathy, remains limited. Photosynthesis is an ideal probe to study allelopathic interactions between marine microalgae, simply because it is one of the main targets. We have validated a new approach allowing to dissect the photosynthetic activities of each microalgae within a mixture, allowing to reveal allelopathic interactions affecting photosynthesis. This thesis focuses on diatoms plastid which, beyond being the energetic center of the cell, also proves to be a specific target of the allelochemical compounds released by their competitors.This methodological approach made it possible to demonstrate the inhibition of the photosynthetic activity of the diatom T. pseudonana by allelochemical compounds released by the dinoflagellate A. carterae. This inhibition involves the dissipation of the electrochemical proton gradient across the thylakoids, probably by amphidinol-like molecules forming pores on biological membranes. We were also able to show two other allelopathic interactions targeting the plastid of diatoms: the role of alkyl-quinolones, released by bacteria, on the photosynthetic and respiratory electron transport chains of the diatom P. tricornutum, and the effects of the filtrate of the dinoflagellate A. minutum on the cytoplasmic and plastid membranes of the diatom C. muelleri., Une des principales forces qui façonnent la dynamique et la structure des communautés phytoplanctoniques est l'inhibition directe du métabolisme des concurrents grâce à l'utilisation de métabolites secondaires. Mais notre compréhension de ce phénomène, appelé allélopathie, reste limitée. La photosynthèse est une sonde idéale pour étudier les interactions allélopathiques entre microalgues marines, car elle en est une des cibles principales. Nous avons validé une approche nouvelle, permettant de disséquer les activités photosynthétiques de chaque microalgue au sein d’un mélange, permettant de dévoiler des interactions allélopathiques ciblant la photosynthèse. Cette thèse se concentre sur le plaste des diatomées, qui, au-delà d’être le centre énergétique de la cellule, s’avèrent aussi être la cible des composés allélochimiques libérés par leurs compétiteurs. Cette approche méthodologique a permis de montrer l’inhibition de l’activité photosynthétique de la diatomée T. pseudonana par des composés allélochimiques libérés par le dinoflagellé A. carterae. Cette inhibition implique la dissipation du gradient électrochimique de proton généré à travers les thylacoïdes, probablement par des molécules de type amphidinols formant des pores sur les membranes biologiques. Au cours de deux collaborations, nous avons montré deux autres interactions allélopathiques ciblant le plaste des diatomées : le rôle des quinolones libérées par des bactéries, sur les chaînes de transport d’électron photosynthétique et respiratoire de la diatomée P. tricornutum, les effets du filtrat du dinoflagellé A. minutum sur les membranes cytoplasmiques et chloroplastiques de la diatomée C. muelleri.

Published
2020

12. Exploring the diversity of cyclic electron flow around photosystem I in microalgae species

Author

Ferté, Suzanne, Biologie du chloroplaste et perception de la lumière chez les micro-algues, Institut de biologie physico-chimique (IBPC (FR_550)), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, Francis-André Wollman, Benjamin Bailleul, and STAR, ABES

Subjects
Spectroscopie d'absorption, [PHYS.PHYS.PHYS-BIO-PH] Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], P700, Cyclic electron transfer, Photosystem, Absorption spectroscopy, Viral infection, Microalgae, Transfert cyclique d’électrons, Infection virale, Microalgues, Photosynthesis, Photosynthèse, Photosystème
Abstract

Microalgae supplies virtually all the oceanic trophic chains and participate in almost half of photosynthesis on Earth. Although their genetic diversity is well known, their functional diversity remains little explored. The main route of photosynthesis, the linear flux of electrons from water to CO2, seems to be well conserved among phylogeny. It involves two photosystems working in series, the photosystem II (PSII) and I (PSI). In plants and green algae, there is a cyclic electron flow that involves only the PSI which would be crucial for photosynthetic regulation. The study of this cyclic electron flow is hampered by the absence of robust method to measure it. We have shown that the most used method for estimating PSI activity is unreliable. On this basis, we propose an alternative method to detect the presence of cyclic electron flow and to study its dependence on the linear flux. We could show very different behaviors between species of microalgae. Finally, the study of an efflorescence of the coccolithophore Emiliania huxleyi in mesocosm allowed us to highlight a signature of the cells infection by a virus which could involve the cyclic electron flow around the PSI., Les micro-algues sont à l’origine de l’immense majorité des chaines trophiques océaniques et participent à presque la moitié de la photosynthèse sur Terre. Si leur diversité génétique est aujourd’hui bien connue, leur diversité fonctionnelle reste encore peu explorée. La voie principale de la photosynthèse, le flux linéaire d’électrons depuis l’eau vers le CO2 semble bien conservé dans la phylogénie. Il fait intervenir deux photosystèmes en série, les photosystèmes II (PSII) et I (PSI). Chez les plantes et les algues vertes, il existe un flux cyclique d’électrons qui ne fait intervenir que le PSI auquel on attribue plusieurs rôles cruciaux dans la régulation de la photosynthèse. L’étude de ce flux cyclique est freinée par l’absence de méthodologie robuste pour le mesurer. Nous avons montré que la méthode la plus utilisée pour estimer l’activité du PSI n’est pas fiable. Sur cette base, nous proposons une méthode alternative pour détecter la présence de ce flux cyclique et pour étudier sa dépendance envers le flux linéaire. Cela a permis de montrer des comportements très différents entre espèces de micro-algues. Enfin, l’étude d’une efflorescence de la coccolithophore Emiliania huxleyi en mésocosme nous a permis de mettre en évidence une signature de l’infection des cellules par un virus qui pourrait faire intervenir le flux cyclique autour du PSI.

Published
2019

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