Interactions between Pisum sativum & pseudomonads, consequences on plant iron nutrition and growth and immunity

Pea has a high potential in agroecology, however, it may suffer from a susceptibility to iron deficiency in calcareous soils. This susceptibility varies depending on cultivars. Pseudomonad siderophores, pyoverdines (pvd), were shown to promote iron nutrition in Arabidopsis and tobacco. The hypothesis was therefore raised that variation in iron susceptibility between pea cultivars could be related to differences in their ability to recruit fluorescent pseudomonads (fp) contributing to siderophore-mediated iron nutrition. Our aims were to compare i) the impact of a susceptible (S) and a tolerant (T) cultivar of pea on fp biodiversity with a focus on their pvd, and in return ii) the impact of …

Reciprocal interactions between plants and fluorescent pseudomonads in relation to iron in the rhizosphere

SPE EA Section 15 : Engineering the rhizosphere: The "biased rhizosphere" concept Ouvrage en 2 volumes Résumé du livre : Molecular Microbial Ecology of the Rhizosphere covers current knowledge on the molecular basis of plant-microbe interactions in the rhizosphere. Also included in the book are both reviews and research-based chapters describing experimental materials and methods. Edited by a leader in the field, with contributions from authors around the world, Molecular Microbial Ecology of the Rhizosphere brings together the most up-to-date research in this expanding area, and will be a valuable resource for molecular microbiologists and plant soil scientists, as well as upper level stud…

Influence of pea genotype on root associated fluorescent pseudomonads, impact on plant iron nutrition

International audience; Pea has a high potential in agroecology because of its ability to fix atmospheric nitrogen and for Humannutrition due to the high amino-acids content of its seeds. However, pea can suffer from a susceptibility toiron deficiency in calcareous soils as expressed by chlorosis symptoms. Previous studies have shown thatsiderophores of model strains of fluorescent pseudomonads (fp), pyoverdines, promote iron nutrition ofarabidopsis and tobacco. We hypothesized that susceptibility to iron deficiency of pea is at least partly dueto its ability to select fluorescent pseudomonad that promote differentially plant nutrition thanks to theirsiderophores.To identify siderophores po…

Contribution of fluorescent pseudomonads to iron nutrition and health of pea

The Pseudomonas fluorescens Siderophore Pyoverdine Weakens Arabidopsis thaliana Defense in Favor of Growth in Iron-Deficient Conditions

SPE EA BIOME IPM UB INRA; International audience; Pyoverdines are siderophores synthesized by fluorescent Pseudomonas spp. Under iron-limiting conditions, these high-affinity ferric iron chelators are excreted by bacteria in the soil to acquire iron. Pyoverdines produced by beneficial Pseudomonas spp. ameliorate plant growth. Here, we investigate the physiological incidence and mode of action of pyoverdine from Pseudomonas fluorescens C7R12 on Arabidopsis (Arabidopsis thaliana) plants grown under iron-sufficient or iron-deficient conditions. Pyoverdine was provided to the medium in its iron-free structure (apo-pyoverdine), thus mimicking a situation in which it is produced by bacteria. Rema…

Cryo-méthodes appliquées à l’étude des interactions entre plantes et Pseudomonas Fluorescents en relation avec le fer dans la rhizosphère

SPEBAPEAIPMBIOmE; Cryo-méthodes appliquées à l’étude des interactions entre plantes et [i]Pseudomonas Fluorescents[/i] en relation avec le fer dans la rhizosphère. 7. Journées Scientifiques et Techniques du Réseau des Microscopistes de l'INRA (RμI)

Diversité et activités microbiennes dans la rhizosphère: des atouts majeurs en agroécologie

National audience; Les rhizodépôts libérés par les plantes stimulent une microflore abondante et active dans la rhizosphère. La diversité des communautés microbiennes correspondantes est influencée par la nature des rhizodépôts (composition, molécules signal) qui diffère selon les génotypes végétaux. Le coût pour la plante correspondant à la libération de ces rhizodépôts est contrebalancé par le bénéfice issu des effets positifs de certaines populations microbiennes rhizosphériques sur la croissance et la santé de la plante-hôte. La connaissance des traits végétaux impliqués dans la sélection de ces populations bénéfiques, au sein des communautés microbiennes telluriques, représente un enje…

Highlighting the role of diversity in driving weed dynamics and weed-crop interactions

SPEBIOME INRA; Le Microscope à Dissection Laser (MDL) est composé de l’association d’un microscope équipé d’objectifs permettant un grossissement x2 à x100 et d’un système optique de découpe laser. Il permet de microdisséquer de façon ciblée des échantillons biologiques, de type bactérien, animal ou végétal. Sa finesse de dissection permet de sélectionner, d’isoler puis de récupérer des cellules cibles afin de concentrer le matériel. Ainsi, il est possible de réaliser des analyses de transcriptomique, de génomique ou de protéomique à partir de cellules cibles. Avant de microdisséquer, la préparation des échantillons est primordiale pour s’assurer de récupérer une qualité et une quantité suf…

5èmes Journées Scientifiques et Techniques du Réseau des Microscopistes INRA. « Imagerie cellulaire en science du vivant : Cryo-microscopies, Dynamiques in vivo et Interactions moléculaires »

National audience; L’imagerie cellulaire, dans le domaine des sciences du vivant, est essentielle à la compréhension des phénomènes cellulaires subcellulaires régulant le fonctionnement des cellules et tissus. En microscopie électronique, la mise en oeuvre de cryo-méthodes permet de préserver l’intégrité moléculaire et spatiale des protéines et lipides intracellulaires ou membranaires (de faible poids moléculaire, présentes en faible quantité ou très labiles) dont la localisation in situ est recherchée afin de caractériser leur organisation, participer à la détermination de leur fonction au sein de la cellule et d’analyser leur distribution. Ces techniques, en pleine évolution, seront abord…

Iron dynamics in the rhizosphere as a case study for analysing interactions among soils, plants and microbes

International audience

Influence du système de sécrétion de type III bactérien dans les intéractions plantes-Pseudomonas spp. fluorescents non pathogènes

http://prodinra.inra.fr/record/271693SPEEAEcolDurCT3; L’objectif de cette thèse a été de contribuer à faire progresser les connaissances sur les interactions bénéfiques entre les plantes et les microorganismes en évaluant la contribution des systèmes de sécrétion de type III (SST3). Une synthèse des connaissances disponibles relatives aux SST3 chez les Pseudomonas non pathogènes, saprotrophes ou mutualistes, montre que les SST3 ne sont pas cantonnés aux interactions parasites ou pathogènes avec les plantes. Dans la première étude expérimentale, nous avons utilisé différents génotypes de Medicago truncatula Gaertn. cv. Jemalong capables (Myc+) ou non (Myc-) d’établir une symbiose mycorhizien…

Analysis of the cross‐regulation between immunity, growth and iron homeostasis in plants

The existence of a tightly regulated balance between growth and immunity in plants has recently emerged. In this study, we challenged this concept thanks to the biological model pyoverdine-Arabidopsis thaliana. Pyoverdine is a siderophore produced by the plant growth promoting rhizobacteria Pseudomonas fluorescens C7R12. Under iron deficiency, P. fluorescens excretes the iron free form of pyoverdine (apo‐pyo) in the soil. Once chelated with iron (ferri‐pyo), the complex is internalized by the bacteria. We demonstrated that Arabidopsis thaliana plants treated by apo‐pyo in a medium containing or not iron internalize pyoverdine. Interestingly, apo‐pyo-treated plants did not show a typical gro…

Report on the interaction between pea and fluorescent pseudomonads and the potential impact on the plant iron nutrition

Metabolic fate of a bacterial siderophore in Arabidopsis thaliana and Pisum sativum in relationship with iron status in plants

Despite its abundance, iron is weakly bioavailable for organisms due to its poor solubility in soils under aerobic conditions. Therefore, plants and other organisms have evolved mechanisms to efficiently assimilate iron from the soil. Non-grass plants use a strategy (strategy I) based on soil acidification, reduction of the Fe3+ in Fe2+ which incorporated in the roots by iron transporters. We previously showed (Shirley et al., 2011; Vansuyt et al., 2007) that iron nutrition and growth of a strategy I plant could be promoted by the ferric-complex of the pyoverdine (Fe-pvd), a siderophore produced by microorganisms. If pyoverdine was further localized in planta using different immunological t…

Reciprocal interactions between plants and fluorescent pseudomonads in relation with iron in the rhizosphere

communication orale invitée; absent

Interactions réciproques entre plantes et Pseudomonas fluorescents en relation avec le fer rhizosphèrique

Influence of pea genotype on root-associated pseudomonads, impact on the plant protection against fungal pathogens

International audience

Importance de la diversité des Pseudomonas rhizosphériques et de celle de leurs sidérophores dans la nutrition en fer de la plante hôte

Influence of pea genotype on root associated fluorescent pseudomonads, consequences for plant iron nutrition

Pea has a high potential in agroecology because of its ability to fix atmospheric nitrogen and in Human nutrition because of the high aminoacid content of its grains. However, pea may suffer from a susceptibility to iron deficiency in calcareous soils. This susceptibility varies depending on cultivars. Pseudomonad siderophores, pyoverdines (pvd), were shown to promote iron nutrition in Arabidopsis and tobacco. Thus, we hypothesize that variations in iron susceptibility between pea cultivars could be related to differences in their ability to recruit fluorescent pseudomonad (fp) contributing to siderophore-mediated iron nutrition. Our aims were to compare i) the impact of a susceptible (S) a…

PIXE ANALYSES OF THE SOLUBLE AND MEMBRANE SE-CONTAINING PROTEINS EXTRACTED FROMCUPRIAVIDUS METALLIDURANSCH34 AFTER SELENIUM OXIDES CHALLENGE

The soil bacterium Cupriavidus metallidurans CH34 resist selenite by reducing it into the insoluble and less toxic elemental selenium. Two mechanisms of reduction of selenium oxides in C. metallidurans CH34 were highlighted: assimilation leading to organic species and detoxification leading to precipitation of selenite in nanoparticules of elemental selenium. The alkyl selenide detected as an intermediate product during assimilation of selenite or as the major accumulated chemical form during assimilation of selenate was identified as selenomethionine.Soluble and membrane proteins were extracted from C. metallidurans CH34 submitted to selenium oxides challenge. After separation by SDS-PAGE,…

Implication of pyoverdines in the interactions of fluorescent pseudomonads with soil microflora and plant in the rhizosphere

International audience