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Genetische Faktoren scheinen den Verlauf nach einer Nierentransplantation zu beeinflussen. In dem Gen des Wasserkanals Aquaporin 5 wurde der SNP beschrieben, der mit Schl��sselmechanismen der Inflammation wie der Immunzellmigration assoziiert ist. Da nach einer Nierentransplantation Absto��ungsreaktionen und Infektionen mit dem Cytomegalievirus auftreten k��nnen, wurde getestet, ob der SNP mit diesen Komplikationen assoziiert ist. In unserer Studie wurden Speichelproben entnommen. Mittels Polymerase-Kettenreaktion wurde die Position -1364 des SNP analysiert. Die Analysen ergaben, dass das C-Allel des SNP ein Risikofaktor f��r eine CMV-Infektion darstellt. Der \(\it AC/CC\)-Genotyp wies ein mehr als doppelt so hohes Risiko f��r eine CMV-Infektion nach Transplantation auf. Der SNP ist in unserem Kollektiv nicht mit der Absto��ungsreaktion assoziiert.

International audience; The role exerted by Aquaporin 4 (AQP4) as a regulator of astrocyte immune functions has been poorly explored. A recent report demonstrates that under neuroinflammatory conditions, the expression of Aqp4 on murine astrocytes is mandatory for the effective control of acute inflammation in the central nervous system. Such an immunomodulatory function appears to be mediated by a promotion of the transforming growth factor beta 1 (Tgfb1) pathway. Here, these results are discussed in the context of neuromyelitis optica (NMO) and multiple sclerosis (MS) progressive forms. It is proposed that NMO and progressive MS might rely on opposite molecular mechanisms involving, in NMO, an acutely-defective AQP4/TGFB1 pathway and, in progressive MS, a chronically-stimulated AQP4/TGFB1 pathway. Data supporting the involvement of angiotensin II as a molecular link between AQP4 and TGFB1 are also reviewed.

Untersucht wurde anhand von retrospektiv erfassten Daten von 27 Patienten "mit Wundheilungsstörungen (WHST)" und 222 Patienten "ohne WHST", ob das Vorliegen des Genotyp DD bzw. ID des 94Ins/DelATTG)-Polymorphismus des NFĸB-Genpromotors und das Vorliegen des Genotyp AA des SNP(-1364A/C) im AQP5-Genpromotor mit dem Auftreten von postoperativen WHST nach neurochirurgischen Eingriffen assoziiert ist. Weitere patienteneigenen Daten wurden ebenfalls untersucht. Im Ergebnis konnte kein statistisch relevanter Zusammenhang zwischen WHST und NFĸB- bzw. AQP5-Genotyp gezeigt werden. Tendenziell könnte das D-Allel des NFĸB-Genotyp aber mit WHST in Zusammenhang stehen. Prognostisch ungünstige Faktoren waren: vorbestehende Dauermedikation mit Antikoagulanzien, niedrige Hb / Hk-Werte, niedrige Erythrozytenanzahl, niedrige Kalziumwerte, leicht erhöhtes CRP, Dicke der kutanen Fettschicht über dem OP-Gebiet, OP-Dauer, Instrumentation bzw. Zementaugmentation sowie starke intraoperative Blutungen.

Bei der Abstoßungsreaktion nach Nierentransplantation scheinen auch genetische Faktoren eine Rolle zu spielen. Interessante Kandidatengene sind Aquaporine. Untersucht wurde der Promotorpolymorphismus AQP3-1431G>A. Bei der Genotypisierung nierentransplantierter Patienten zeigte sich, dass Patienten mit A-Genotyp häufiger eine Abstoßungsreaktion erlitten haben als der G-Genotyp. Im Luziferaseassay wurde beim A-Genotyp eine höhere Promotoraktivität gemessen, sowohl unter basalen Bedingungen als auch bei Zugabe der Transkriptionsfaktoren SP1 und CREB. Der G-Genotyp zeigt im Electrophoretic Mobility Shift Assay eine verstärkte Bindung zu Transkriptionsfaktoren. Bei Messung der AQP3-mRNA-Expression zeigten sich keine genotypabhängigen Unterschiede in PBMCs unter basalen Bedingungen, unter Stimulation mit cAMP aber eine verringerte Expression bei Vorliegen des G-Allels. Eine erhöhte AQP3-Expression scheint also mit ursächlich für Abstoßungsreaktionen nach Nierentransplantation zu sein.

Application pratique de la dynamique moléculaire au passage de l'eau dans une aquaporine.. Conférence de découverte sur la dynamique moléculaire

Leaf hydraulic conductance (Kleaf) and capacitance (Cleaf) are among the key parameters in plant-water regulation. Understanding the responses of these hydraulic traits to drought conditions remains a challenge for describing comprehensive plant-water relationships. The ability of an organism to resist and/or tolerate embolism events, which may occur at high negative pressure caused by hydric stress, relies on how well it can sustain a hydraulic system in a dynamic equilibrium. Populus deltoides is a water-saving tree species with a stomatal conductance that declines rapidly with reduced water availability. Under unfavorable conditions, the stomatal control of transpiration is known to be closely coordinated with a loss of plant hydraulic functioning that can ultimately result in hydraulic failure through xylem embolism, notably in leaves. The effects of drought on leaf hydraulics are also related to regulation in water permeases such as the aquaporins. To describe the responses linked to leaf hydraulics under severe drought and rewatering conditions, water-stressed poplars were monitored daily on an ecophysiological and a molecular scale. A structural and expression analysis on a set of aquaporins was carried out in parallel by in situ hybridization analysis and quantitative PCR. In complement, water distribution in water-challenged leaves was investigated using X-ray microtomography. A general depression of leaf hydraulic conductance and relative water content occurred under drought, but was reversed when plants were rewatered. More interestingly, (i) extreme leaf water deficiency led to marked xylem and lamina embolism, but a degree of hydric integrity in the midrib extraxylem territories and the bundle sheath of the minor veins was maintained, and (ii) the sub-tissue water allocation correlated well with an over-accumulation of several PIP and TIP aquaporins. Our multi-facet molecular ecophysiological approach revealed that leaves were able to secure a certain level of hydric status, in particular in cell territories near the “living ribs”, which provided rapid hydric adjustment responses once favorable conditions were restored. These findings contribute to an integrated approach to leaf hydraulics, thus favoring a better understanding of the cell mechanisms involved in tree vulnerability to climate changes.

Biological disease control through the use of microorganisms has a great potential for future use in integrated pest management. In a multidisciplinary and fundamental context of molecular physio-phytopathology and to provide solutions for the actors in the olive profession and the consumers, we have been studying the activity of a fungal biocontrol agent, Trichoderma harzianum (strain Ths97) against the olive tree pathogen Fusarium solani (strain Fso14), which causes major problems for olive production in Tunisia and elsewhere. The project consists of two parts. In the first part, we have demonstrated that Ths97 is a biocontrol agent effective against the F. solani Fso14 pathogen. Induction of plant defence responses by Ths97 was shown to be partly responsible for the biocontrol effect. In vitro tests further showed that Ths97 develops mycoparasitic activities towards F. solani Fso14, by forming infection structures such as hyphae windings and wedges, appressoria and papillae. In the second part of the study, we investigated the Major Intrinsic Proteins (MIP) superfamily in the Trichoderma genus. This multigenic family has never been investigated in a hyperparasitic fungal species. Seven MIP members are present in T. harzianum, and are classified into 3 subgroups: AQP, AQGP and XIP. Their three-dimensional structures and their putative involvement in transport of water and certain polyols have been examined. Finally, their transcription profiles were monitored in Ths97 in planta in antagonistic situations and in vitro in a parasitic situation with Fso14 and show that 4 MIP are expressed and regulated differentially during the interaction. Our work has shown that Ths97 must be considered as a biological control agent and biostimulator of plant defences, and that MIPs are involved in the trophic relationships between T. harzianum and the environment. These data contributes to the further development of T. harzianum as an efficient biocontrol agent for sustainable protection of olive trees in Tunisia and around the world.; La lutte biologique par utilisation de micro-organismes a indéniablement un potentiel de développement considérable. Dans un contexte multidisciplinaire et fondamental de physio-phytopathologie moléculaire et répondant à d’éminents enjeux appliqués et attendus par les acteurs de la profession oléicole et les consommateurs, nous nous sommes projetés dans l’étude des propriétés intrinsèques d’un agent de biocontrôle fongique, Trichoderma harzianum (souche Ths97) contre l’agent de la fusariose Fusarium solani (souche Fso14), qui sévit sévèrement sur une culture pérenne majeure pour la Tunisie, l’oléiculture. Deux axes de recherche ont été menés. Dans le premier axe, nous avons démontré que Ths97 est un agent de biocontrôle efficace contre la virulence de F. solani Fso14. Cette capacité s’accompagne d’une accumulation des défenses chez le partenaire végétal, des accumulations qui sont d’autant plus fortes quand l’agent bénéfique est en présence du pathogène (événements de priming). De même, des tests in vitro montrent que Ths97développe des activités mycoparasites envers F. solani Fso14, en émettant des structures d’infection classiques tels des enroulements et accolements d’hyphes, des appressoria et des papilles. Quant au second axe d’étude, nous avons étudié la superfamille des perméases Major Intrinsic Proteins (MIP) dans le genre Trichoderma. Cette famille multigénique n’a jamais été étudiée chez un agent fongique hyperparasite. Sept membres MIP sont présents chez T. harzianum, et se classent en 3 sous-groupes, les AQP, les AQGP et les XIP. La modélisation des structures tridimensionnelles et les fonctions putatives de transport pour l’eau et quelques polyols ont été étudiées. Enfin, leurs patrons transcriptionnels ont été suivis chez Ths97 in planta en situation d’antagonisme et in vitro en situation de parasitisme vis-à-vis de Fso14, et montrent que 4 MIP sont exprimées et régulées différentiellement selon que Ths97 est au contact de Fso14 ou pas. Nos travaux ont donc mis en lumière que Ths97 doit être considéré comme un agent biofongicide et biostimulateur de défenses végétales, puis que les MIP seraient impliqués dans les relations trophiques que met en place T. harzianum avec son environnement. Ces données devraient intégrer le développement de procédés plus efficaces et/ou plus durables pour la protection des cultures d’oliviers en Tunisie ainsi qu’à travers le monde.

National audience; Plasma membrane intrinsic proteins (PIPs) are aquaporins that facilitate the passive movement of water through biological membranes. These channels are involved in numerous physiological and cellular processes such as hydraulic conductivity, transpiration, photosynthesis and osmoregulation in plants. In a context of climatic changes, they could turn out to be key targets for selection of crop varieties optimized for water use efficiency. Whereas PIP mRNA levels in maize tissues vary according to the developmental stages and under varying environmental conditions, the molecular actors and mechanisms regulating the transcription of these genes remain largely unknown. Relying on the genetic material (254 maize genotypes and ~1000 K SNPs collection) and expertise of the European DROPS (DROught tolerant yielding PlantS) project, we performed GWAS (genome-wide association study) analyses in order to identify promising eQTLs (expression quantitative trait loci) associated with variation in the expression of five PIP genes in the mature and elongation zones of the leaf. In most cases, highly significant eQTLs were identified close to the PIP genes themselves suggesting the large impact of cis-regulation, as well as numerous promising distal eQTLs that appear to be mainly zone-specific. Conditional GWAS, avoiding the cis-eQTLs effects, allowed the identification of even more proximal and distal eQTLs, highlighting the complex regulation of the PIP gene expression. Deeper analyses and functional validation of several eQTLs are currently ongoing.

Das Atemwegsepithel grenzt das gasgefüllte Kompartiment der Atemwege vom wässrigen Kompartiment des Organsimus ab und bildet damit einen sogennante Luft-Flüssigkeits Übergang (ALI = Air-Liquid Interface). Die apikale Oberfläche ist dem gasgefüllten Kompartiment ausgesetzt und wird durch einen dünnen Flüssigkeitsfilm (ASL = airway surface liquid) überlagert. Für die Lungenfunktion ist die Volumenhomöostase des ASL von besonderer Bedeutung. Die Dysregulation des ASL-Volumens trägt wesentlich zur Pathogenese von Lungenerkrankungen wie COPD (chronic obstructive pulmonary disease = chronisch obstruktive Lungenkrankheit), Asthma und ARDS (acute respiratory distress syndrom = akutes Atemnotsyndrom) bei. Bisher ging man davon aus, dass das ASL-Volumen in erster Linie durch Regulation des transepithelialen Ionentransports eingestellt wird. Hingegen wurde der Einfluss der epithelialen Wasserpermeabilität auf die ASL-Volumenhomöostase wenig untersucht. In dieser Arbeit wurde die Auswirkung einer langfristigen apikalen Volumenexpansion (AVE) auf den transepithelialen Wasser- und Ionentransport untersucht. Als Zellmodelle wurden primäre ausdifferenzierte humane Trachealepithelzellen und NCI-H441 Lungenepithelzellen als ALI-Kulturen verwendet. Eine AVE wurde durch Zugabe eines definierten Volumens isotoner NaCl-Lösung auf die apikale Oberfläche herbeigeführt. Eine AVE induzierte eine unmittelbare Aktivierung der Natriumresorption durch eine proteolytische Aktivierung des ENaC (epithelial Na+-channel = epithelialer Natriumkanal). Für die Wasserresorption konnten eine Phase mit geringer Transportrate (LRS = low resorptive state) und eine Phase mit hoher Transportrate (HRS = high resorptive state) identifiziert werden. Dabei erfolgte die hauptsächliche Kompensation der AVE während des HRS. Der Übergang zwischen beiden resorptiven Zuständen war reversibel und korrelierte nicht mit der Aktivierung des Ionentransportes, sondern mit einer Erhöhung der Wasserpermeabilität der Epithelien, die durch den Inhibitor Cu2+ des Wasserkanals Aquaporin 3 (AQP 3) blockiert werden konnte. Expressionsstudien zeigten, dass das HRS mit einer transienten Erhöhung der AQP 3 Expression und dessen Einbau in die laterale Membran der Epithelzellen einherging. Die Unterdrückung der AQP 3 Expression mittels stabil überexprimierter shRNA (short-hairpin ribonucleic acid = kleine Haarnadelribonukleinsäure) verzögerte das Einsetzen des HRS um mehrere Stunden. Aus diesen Ergebnissen lässt sich ein neues Funktionsmodell zur Kompensation einer AVE in Lungenepithelien ableiten: Eine AVE aktiviert die transzelluläre epitheliale Natriumresorption durch proteolytische Aktivierung des ENaC. Diese Aktivierung kann einen Mechanismus zur Registrierung einer AVE darstellen, ist aber nicht für die hauptsächliche kompensatorische Resorption verantwortlich. Die eigentliche Kompensation der AVE erfolgt während des HRS durch eine erhöhte Wasserpermeabilität, an der auch AQP 3 beteiligt ist. Dabei folgt die Wasserresorption einem Weg über die apikale Zellmembran in das Zytoplasma und von dort über Aquaporine in den lateralen interstitiellen Spalt zwischen benachbarten Epithelzellen, von welchem es als Resorbat in das basolaterale Kompartiment übergeht. Dieser translaterale Transportweg wird durch den Na+/K+ ATPase (ATPase: Adeonsintriphosphatase) vermittelten Ionentransport angetrieben.

Ziel der vorliegenden Arbeit war es, humanes Glioblastomgewebe zu kultivieren und in Abhängigkeit der Kultivierungszeit zu untersuchen. Bei dem zur Verfügung gestellten Gewebe handelte es sich um einen höchst malignen, hirneigenen Tumor der WHO-Klasse IV. Das OP-Resektat wurde sowohl unmittelbar nach Entnahme fixiert als auch in kultivierter Form fixiert und untersucht. Dabei sollte das Vorhandensein Orthogonaler Partikel Komplexe, der sogenannten OPKs, mittels der Gefrierbruchmethode ausgewertet werden. OPKs sind als morphologisches Äquivalent des Wasserkanalproteins Aquaporin 4 (AQP4) integraler Bestandteil jeder Astrozytenmembran. Wichtig war es, einen Hinweis darauf zu bekommen, ob diese Strukturen und somit die Expression von AQP4 in vitro anhand eines Kultivierungsmodells stabilisiert werden können und wie sie sich verhalten und/oder, ob sich OPKs in Abhängigkeit von der Kultivierungsdauer bilden bzw. erhalten bleiben. Methodisch kamen neben dem Gefrierbruch die konventionelle Elektronenmikroskopie und Immunhistologie zum Tragen. Dabei wurde anhand der Elektronenmikroskopie die Ultrastruktur und mittels Immunhistologie die Expression von AQP4 und AQP1 untersucht und ausgewertet. In der Arbeit konnte zum einen gezeigt werden, dass sich OPKs in Kultur halten lassen, wenn diese schon frisch nach Entnahme nachzuweisen waren, zum anderen, dass AQP4 und AQP1 in Kultur exprimiert werden. Überraschend war die Tatsache, dass sich die Membranarchitektur von unkultiviertem und kultiviertem Gewebe nicht unterscheiden ließ, der Ultradünnschnitt wies jedoch bereits nach einem Tag in Kultur einen zerstörten Gewebeverband auf. Es scheint daher von großer Wichtigkeit, die Ultrastruktur bei Kultivierung näher zu betrachten, da gezeigt werden konnte, dass die Membranbeschaffenheit wenig über den Erhalt der typischen Zellorganellen einer intakten Zelle aussagen kann. Trotz der großen Fortschritte in den letzten Jahren auf diesem Gebiet der Gehirntumorforschung bedarf es jedoch noch weiterer Forschung zur Etablierung eines funktionierenden Kultivierungssystems von Gliomgewebe. Zukunftsziel der Erarbeitung neuer Systeme ist dabei nicht nur ein besseres Konzept bei der Therapiewahl, sondern auch durch schnellere und reproduzierbare Kultivierungsmethoden neue Medikamente an humanem Gewebe zu testen. Dies kann in Zukunft eine verbesserte Diagnose und Prognose möglich machen. Wie gezeigt werden konnte, ist eine standardisierte Kultivierung von humanem Gliomgewebe verbesserungswürdig. Die Übertragbarkeit der Wirkung von Medikamenten von Tiermodellen auf den Menschen kann dabei noch nicht vorausgesagt werden. Dennoch lohnt es sich, den Fokus weg von Tierversuchen und hin zu in vitro Kultivierung zu lenken.

Dear Colleagues, During recent years, proteomics has become the key to understand physiological processes involving the regulation of expression of many genes from transcription to production of metabolites. Each of these steps is part of the overall mechanisms tightly coordinated to allow organisms to develop or adapt to their environment. Plant proteomics has been dramatically expanding since the beginning of the 2000s thanks to major advances in the development of three technological tools. It started with the sequencing of full genomes and collection of expressed sequence tags or RNAs. The release of the Arabidopsis thaliana genome in 2000 has allowed this plant to become a pioneer model for dicots, and particularly for proteomics studies. More than 650 articles have been published in this field since 2000. A. thaliana has been quickly followed by Brachypodium distachyon as a model for monocots and by plants of agronomical interest such as rice, maize, sugarcane, alfalfa, tomato or flax. Apart from these plants, others for which sequencing data were not available could be studied as well, thanks to the possibility to work with heterologous data. In addition, over the last decade, remarkable technological advances have been achieved due to improvements in mass spectrometry which allowed refining the coverage of total proteomes and sub-proteomes from small amounts of starting material and characterizing post-translational modifications and protein-protein interactions. Furthermore, quantitative proteomics now provides detailed information on organ- and tissue-specific regulatory mechanisms responding to a variety of individual stresses or stress combinations during the plant life cycle. Finally, the development of computational tools allows managing the tremendous amount of data generated by mass spectrometers to deliver relevant biological information. Thus, powerful mass spectrometry-based technologies now provide unprecedented insights into the composition, structure, function and control of the proteome, shedding light on complex biological processes and phenotypes. This Special issue of Proteomes welcomes submissions of original research or review articles aiming at deciphering physiological processes with the use of proteomics tools. Contributions will deal with the dynamics of proteins in their native and modified forms, with the combination of several “omics” approaches in contrasted physiological situations as well as with technical advances in the proteomic field.

Major intrinsic proteins (MIP) are characterized by a transmembrane pore-type architecture that facilitates transport across biomembranes of water and a variety of low molecular weight solutes. They are found in all parts of life, with remarkable protein diversity. Very little is known about MIP from fungi. And yet, it can legitimately be stated that MIP are pivotal molecular components in the privileged relationships fungi enjoy with plants or soil fauna in various environments. To date, MIP have never been studied in a mycoparasitism situation. In this study, the diversity, expression and functional prediction of MIP from the genus Trichoderma were investigated. Trichoderma spp. genomes have at least seven aquaporin genes. Based on a phylogenetic analysis of the translated sequences, members were assigned to the AQP, AQGP and XIP subfamilies. In in vitro and in planta assays with T. harzianum strain Ths97, expression analyses showed that four genes were constitutively expressed. In a mycoparasitic context with Fusarium solani, the causative agent of fusarium dieback on olive tree roots, these genes were up-regulated. This response is of particular interest in analyzing the MIP promoter cis-regulatory motifs, most of which are involved in various carbon and nitrogen metabolisms. Structural analyses provide new insights into the possible role of structural checkpoints by which these members transport water, H2O2, glycerol and, more generally, linear polyols across the membranes. Taken together, these results provide the first evidence that MIP may play a key role in Trichoderma mycoparasitism lifestyle.

Background The major intrinsic protein (MIP) family is a family of proteins, including aquaporins, which facilitate water and small molecule transport across plasma membranes. In plants, MIPs function in a huge variety of processes including water transport, growth, stress response, and fruit development. In this study, we characterize the structure and transcriptional regulation of the MIP family in grapevine, describing the putative genome duplication events leading to the family structure and characterizing the family’s tissue and developmental specific expression patterns across numerous preexisting microarray and RNAseq datasets. Gene co-expression network (GCN) analyses were carried out across these datasets and the promoters of each family member were analyzed for cis-regulatory element structure in order to provide insight into their transcriptional regulation. Results A total of 29 Vitis vinifera MIP family members (excluding putative pseudogenes) were identified of which all but two were mapped onto Vitis vinifera chromosomes. In this study, segmental duplication events were identified for five plasma membrane intrinsic protein (PIP) and four tonoplast intrinsic protein (TIP) genes, contributing to the expansion of PIPs and TIPs in grapevine. Grapevine MIP family members have distinct tissue and developmental expression patterns and hierarchical clustering revealed two primary groups regardless of the datasets analyzed. Composite microarray and RNA-seq gene co-expression networks (GCNs) highlighted the relationships between MIP genes and functional categories involved in cell wall modification and transport, as well as with other MIPs revealing a strong co-regulation within the family itself. Some duplicated MIP family members have undergone sub-functionalization and exhibit distinct expression patterns and GCNs. Cis-regulatory element (CRE) analyses of the MIP promoters and their associated GCN members revealed enrichment for numerous CREs including AP2/ERFs and NACs. Conclusions Combining phylogenetic analyses, gene expression profiling, gene co-expression network analyses, and cis-regulatory element enrichment, this study provides a comprehensive overview of the structure and transcriptional regulation of the grapevine MIP family. The study highlights the duplication and sub-functionalization of the family, its strong coordinated expression with genes involved in growth and transport, and the putative classes of TFs responsible for its regulation. Electronic supplementary material The online version of this article (10.1186/s12864-018-4638-5) contains supplementary material, which is available to authorized users.

Membrane Transport in Plants

Root hydraulics: a key trait in plant adaptation to stresses . 2nd Workshop on Plant Development & Drought Stress

Interactomics reveals novel regulatory mechanisms of plant aquaporins. Congrès Spectrométrie de Masse, Métabolomique et Analyse Protéomique (SMMAP)

Regulation of aquaporins and plant hydraulics under water and salt stress. XIX International Botanical Congress

Multi-scale modeling of water transport in plant roots. GDR PhyP - Biophysique et biomécanique des plantes

Der oben genannte SNP ist eine Genvariante des AQP5. Bis dato ist unklar, welcher Mechanismus dem Überlebensvorteil von C-Allelträgern zugrunde liegt sowie warum der SNP einen hohen Einfluss auf die AQP5-Expression hat. Potentielle Ursachen für den Einfluss des AQP5 A (-1364) C Promotorpolymorphismus auf die AQP5-Expression könnte eine an bestimmten Positionen Genotyp- abhängige differenzielle Methylierung des AQP5- Promotors sowie eine an bestimmten Positionen durch Sepsis induzierte Methylierung sein. Die Position -937 könnte eine mögliche Schlüsselrolle in der Pathogenese der Sepsis spielen, da in diesem Bereich Transkriptionsfaktoren binden, welche für die Inflammation und die AQP5-Expression essentiell sind. Zudem scheint sie einen möglichen Prädiktor für das Outcome bei septischen Patienten darzustellen.

Die große Variabilität im postoperativen Verlauf einer Nierentransplantation kann durch die genetische Variabilität des Patienten beeinflusst werden. Aquaporine stellen einen möglichen Ansatzpunkt für den unterschiedlichen postoperativen Verlauf dar. Ziel der Promotionsarbeit war es den AQP2 Promotorpolymorphismus funktionell zu charakterisieren. Mittels Reportergenassays wurde die Funktionalität des Promotors getestet. Weiterhin erfolgte eine Assoziationsstudie. Unter basalen Bedingungen als auch unter Überexpression zeigt der Promotorpolymorphismus eine stärkere Aktivität beim G-Allel. Die Transplantatfunktion sowie die Rate der Abstoßungsreaktion, unterschied sich nicht zwischen den Patientengruppen. Diese Studie hat einen funktionellen Polymorphismus gezeigt. Dieser zeigt eine erhöhte Aktivität beim G-Allel unter basalen und stimulatorischen Bedingungen. Der Promotorpolymorphismus scheint nicht mit der Transplantatfunktion oder der Abstoßungsreaktion assoziiert zu sein.

Quantitative genetics analysis of root hydraulics uncovers novel pathways of plant adaptation to the environment. VIB Conference 'At the Forefront of Plant Research'

Biologie Végétale - Nutrition et Métabolisme

Aquaporins (AQPs) are essential channel proteins that execute multi-functions throughout plant growth and development, including water transport, uncharged solutes uptake, stress response, and so on. Here, we report the first genome-wide identification and characterization AQP (BvAQP) genes in sugar beet (Beta vulgaris), an important crop widely cultivated for feed, for sugar production and for bioethanol production. Twenty-eight sugar beet AQPs (BvAQPs) were identified and assigned into five subfamilies based on phylogenetic analyses: seven of plasma membrane (PIPs), eight of tonoplast (TIPs), nine of NOD26-like (NIPs), three of small basic (SIPs), and one of x-intrinsic proteins (XIPs). BvAQP genes unevenly mapped on all chromosomes, except on chromosome 4. Gene structure and motifs analyses revealed that BvAQP have conserved exon-intron organization and that they exhibit conserved motifs within each subfamily. Prediction of BvAQPs functions, based on key protein domains conservation, showed a remarkable difference in substrate specificity among the five subfamilies. Analyses of BvAQPs expression, by mean of RNA-seq, in different plant organs and in response to various abiotic stresses revealed that they were ubiquitously expressed and that their expression was induced by heat and salt stresses. These results provide a reference base to address further the function of sugar beet aquaporins and to explore future applications for plants growth and development improvements as well as in response to environmental stresses.

Abscisic Acid Participates in Root Developmental andHydraulic Responses to Water Deficit in Arabidopsis. Montpellier Lateral Root workshop

Regulation of root water transport under flooding. XIX International Botanical Congress

Control of aquaporins and plant hydraulics by environmental and hormonal factors. Mini-Symposium on Plant Stress Biology

Soil water uptake by roots is central for plant growth and survival. Flooding, as many other environmental constraints such as drought, nutrient deprivation or oxidative stress exerts deep effects on root functions by altering root water permeability (root hydraulic conductivity; Lpr). These effects, which are mediated mainly through the regulation of aquaporins, are fundamental for adaptation of wild plant species to diverse natural habitats and a major target for crop improvement. However, the signaling mechanisms which link soil properties to root hydraulics and aquaporin functions remain largely unknown. We have been investigating the genetic bases of root hydraulics in the model plant, Arabidopsis thaliana. Using quantitative genetics approaches, including linkage mapping and genome-wide association mapping, we have identified several genes controlling Lpr. The signaling pathway for regulation of Lpr by a RAF-like MAP3 kinase named Hydraulic Conductivity of Root 1 (HCR1) will be discussed in details (Shahzad et al (2016) Cell 167: 87-98.e14). This protein kinase delineates a combinatorial signaling pathway integrating two soil signals, K+ and O2 availability, to regulate root hydraulics and hypoxia responsive genes, through the control of RAP2.12, a key transcriptional regulator of the core anaerobic response. In addition, several other candidate genes identified during this study offer interesting perspectives for understanding as yet unknown mechanisms involved in the regulation of root hydraulics.

Phosphoproteomics and interactomics reveal novel regulatory mechanisms of plant aquaporins. Congrès de la Société Française d'Electrophorèse et d'Analyse Protéomique (SFEAP)

Regulation of root water transport by Casparian strip domain-like proteins. . Plant Biology Europe EPSO/FESPB 2016 Congress

病理学(第一)教室小林模雄教授退任記念特別号

17 páginas.-- 6 figuras.-- 5 tablas.-- 89 referencias.-- Additional Supporting Information may be found in the online version of this article at the publisher’s web-site, The adaptation capacity of olive trees to different environments is well recognized. However, the presence of microorganisms in the soil is also a key factor in the response of these trees to drought. The objective of the present study was to elucidate the effects of different arbuscular mycorrhizal (AM) fungi coming from diverse soils on olive plant growth and water relations. Olive plants were inoculated with native AM fungal populations from two contrasting environments, that is, semi-arid – Freila (FL) and humid – Grazalema (GZ) regions, and subjected to drought stress. Results showed that plants grew better on GZ soil inoculated with GZ fungi, indicating a preference of AM fungi for their corresponding soil. Furthermore, under these conditions, the highest AM fungal diversity was found. However, the highest root hydraulic conductivity (Lp) value was achieved by plants inoculated with GZ fungi and growing in FL soil under drought conditions. So, this AM inoculum also functioned in soils from different origins. Nine novel aquaporin genes were also cloned from olive roots. Diverse correlation and association values were found among different aquaporin expressions and abundances and Lp, indicating how the interaction of different aquaporins may render diverse Lp values., The study was supported by the Ministry of Economy and Competitiveness of Spain (Juan de la Cierva Program) and Junta de Andalucía (P10-CVI-5920 project) for research funding.

Hydraulic capacitance (C) in a plant tissue buffers the xylem tension, storing and releasing water and has been highlighted in recent years as an important factor that affects water relations such as drought tolerance and embolism formation. Aquaporins (AQPs) are well known to control leaf hydraulic resistance (Rh) but their role in the control of C is unknown. Here, we assess Rh and C on detached grapevines wild-type (WT) (cv. Brachetto) leaves and over-expressing the aquaporin gene VvPIP2;4N (OE). For this purpose, we developed a new method inspired from the pressure-volume curve technique and the rehydration-kinetic-method, which allowed us to monitor the dynamics of dehydration and rehydration in the same leaf. The recovery after dehydration was measured in dark, light non-transpirative conditions, light-transpirative conditions and light-transpirative condition adding abscisic acid. Pressurizing to dehydrate leaves in the OE line, the recorded Rh and C were respectively lower and higher than those in the WT. The same results were obtained in the dark recovery by rehydration treatment. In the presence of light, either when leaves transpired or not (by depressing vapor pressure deficit), the described effects disappeared. The change in Rh and C did not affect the kinetics of desiccation of detached leaves in dark in air, in OE plants compared to WT ones. Our study highlighted that both Rh and C were influenced by the constitutive over-expression of VvPIP2;4N. The effect of AQPs on C is reported here for the first time and may involve a modulation of cell reflection coefficient.

X-Intrinsic Proteins (XIP) were recently identified in a narrow range of plants as a full clade within the aquaporins. These channels reportedly facilitate the transport of a wide range of hydrophobic solutes. The functional roles of XIP in planta remain poorly identified. In this study, we found three XIP genes (HbXIP1;1, HbXIP2;1 and HbXIP3;1) in the Hevea brasiliensis genome. Comprehensive bioinformatics, biochemical and structural analyses were used to acquire a better understanding of this AQP subfamily. Phylogenetic analysis revealed that HbXIPs clustered into two major groups, each distributed in a specific lineage of the order Malpighiales. Tissue-specific expression profiles showed that only HbXIP2;1 was expressed in all the vegetative tissues tested (leaves, stem, bark, xylem and latex), suggesting that HbXIP2;1 could take part in a wide range of cellular processes. This is particularly relevant to the rubber-producing laticiferous system, where this isoform was found to be up-regulated during tapping and ethylene treatments. Furthermore, the XIP transcriptional pattern is significantly correlated to latex production level. Structural comparison with SoPIP2;1 from Spinacia oleracea species provides new insights into the possible role of structural checkpoints by which HbXIP2;1 ensures glycerol transfer across the membrane. From these results, we discuss the physiological involvement of glycerol and HbXIP2;1 in water homeostasis and carbon stream of challenged laticifers. The characterization of HbXIP2;1 during rubber tree tapping lends new insights into molecular and physiological response processes of laticifer metabolism in the context of latex exploitation.

Cell biology of aquaporins in rice. Doctoriales Transfrontalières "Collaborative Innovation"

This thesis discusses various situations linked to transport at the nanoscale. The first chapter is an introduction to nanofluidics, containing a review of characteristic lengths, forces, or phenomena existing at the nanoscale. The second chapter is a study of the impact of geometry on the hydrodynamic permeability of a nanopore. This study, inspired by the shape of aquaporins, suggests a possible optimisation of permeability for bi-conical channels. The third chapter is a study of capillary filing inside subnanometric carbon channels which highlights the importance of the disjoining pressure induced by the fluid structuring inside the nanochannel. The fourth chapter is a study of nanofluidic diode, a component known to mimic the behaviour of semiconductor diode. The study highlights a strong coupling between water and ion dynamics which leads to a water flow rectification inside the diode. The fifth and last chapter is a study of the origin of commonly observed pink noise (1=f) in ionic current measurements through nanopores, Cette thèse décrit diverses situations liées au transport fluidique aux nano-échelles. Le premier chapitre est une introduction à la nanofluidique qui contient une revue des longueurs caractéristiques, des forces et des phénomènes présents aux nano-échelles. Le deuxième chapitre est une étude de l'impact de la géométrie sur la perméabilité hydrodynamique d'un nanopore. Inspirée par la forme des aquaporines, cette étude suggère une optimisation possible pour des canaux biconiques. Le troisième chapitre est une étude du remplissage capillaire dans des canaux sub-nanométriques en carbone. Cette étude montre l'importance de la pression de disjonction induite par la structure du fluide sur le remplissage. Le quatrième chapitre est une étude d'une diode nanofluidique, un composant connu pour imiter le comportement d'une diode à semi-conducteur. On montre qu'un fort couplage entre l'eau et la dynamique des ions entraîne une rectification du flux d'eau à l'intérieur de la diode. Le cinquième et dernier chapitre est une étude de l'origine du bruit rose (1=f) communément observé lors des mesures de courant ionique dans les nanopores

Afin d’aborder l’impact du stress hydrique sur le fonctionnement hydraulique foliaire, des plants de Populus tremula x alba ont été soumis à un stress hydrique modéré ou sévère pendant une semaine par ajout de PEG dans la solution nutritive. La mesure de paramètres écophysiologiques et moléculaires tissus spécifiques a permis de dégager plusieurs tendances sur la caractérisation de l’influence du stress. Les deux types de stress n’ont que peu d’impact sur la croissance et la capacité de synthèse de biomasse de la plante. L’analyse des mouvements d’eau (résistance et capacitance) au sein de la feuille montrent que ceux-ci sont peu perturbés chez la feuille mature par le stress. La majeure partie de la résistance chez la feuille mature est située dans le mésophylle. Ces absences de variations peuvent être corrélées à une inhibition de l’expression des gènes codant des aquaporines de type PIP et TIP lors du stress sévère au sein du mésophylle. Cependant, une augmentation de la teneur en eau au sein des feuilles matures pendant le stress sévère a pu être mise en évidence. Une surexpression de certaines isoformes d’aquaporines au sein des nervures nous permet de formuler l’hypothèse de l’existence de territoires restant bien irrigués au sein de la feuille au cours du stress hydrique. De plus, une diminution de la densité de nervures majeures au niveau des feuilles néoformées au cours du stress a été observée, nous permettant de supposer une modulation de l’architecture foliaire en réponse au stress hydrique.

National audience; Plant aquaporins play key roles in the cellular water permeability by enhancing the transport of water molecules across lipophilic membranes. In maize, four aquaporin subfamilies were identified, among them were found the PIPs standing for plasma membrane intrinsic proteins. Despite the fact that PIP aquaporins are water channels, their function in the plant response to water deficit is not well characterized (Chaumont and Tyerman, 2014). Gene candidate approaches based on the overexpression of one specific PIP gene can lead to either deleterious or beneficial effects for plants under water shortage. Microarray global expression studies on five Arabidopsis thaliana accessions showed a decreased transcription of most PIP genes under progressive drought (Alexandersson et al., 2010). In addition, physiological and pharmacological approaches conducted among several crops showed that aquaporins are involved in both leaf elongation and transpiration rates in response to atmospheric water deficit (Sadok and Sinclair, 2010; Caldeira et al., 2014). Altogether these data indicate that aquaporins are involved in the plant response to water limitation. Under the frame of the European DROPS project, the expression of 12 PIP isoforms was investigated by quantitative PCR in 30 maize lines grown under two contrasted water regimes in the PhenoArch phenotyping platform (LEPSE, Montpellier) where biomass, water use efficiency and transpiration were measured in parallel. Under water limitation, the mRNA level of PIPs belonging to the PIP1 group was weakly regulated while it was down-regulated for most PIP2s, in both leaf elongation and mature zones. PIP expression pattern to water deficit also relied upon the plant life cycle. Furthermore, principal component analysis revealed that expression of most PIPs contributed to the first component while biomass and hydraulic parameters contributed to the second component in well-watered conditions. Under water deficit, this distribution changed indicating that aquaporin expression adjustment to water limitation is involved in the regulation of these physiological parameters.

Aquaporins are water channel proteins that mediate the fine-tuning of cell membrane water permeability during development or in response to environmental stresses. The present work focuses on the oxidative stress-induced redistribution of plasma membrane intrinsic protein (PIP) aquaporins from the plasma membrane (PM) to intracellular membranes. This process was investigated in the Arabidopsis root. Sucrose density gradient centrifugation showed that exposure of roots to 0.5 mM H2O2 induces significant depletion in PM fractions of several abundant PIP homologs after 15 min. Analyses by single-particle tracking and fluorescence correlative spectroscopy showed that, in the PM of epidermal cells, H2O2 treatment induces an increase in lateral motion and a reduction in the density of a fluorescently tagged form of the prototypal AtPIP2;1 isoform, respectively. Co-expression analyses of AtPIP2;1 with endomembrane markers revealed that H2O2 triggers AtPIP2;1 accumulation in the late endosomal compartments. Life-time analyses established that the high stability of PIPs was maintained under oxidative stress conditions, suggesting that H2O2 triggers a mechanism for intracellular sequestration of PM aquaporins without further degradation. In addition to information on cellular regulation of aquaporins, this study provides novel and complementary insights into the dynamic remodeling of plant internal membranes during oxidative stress responses.

Aquaporins: how water channel proteins favour plant life in an ever changing environment. RIKEN Research Center