Search results for "pseudomonas"

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

2019

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…

Impact du cuivre sur les populations de Pseudomonas fluorescents. Variabilité génétique et capacités adaptatives

1999

National audience

Importance of genetic plasticity for microbial adaptation to pesticide biodegradation: in vitro evolution of Pseudomonas sp. ADP under atrazine or cy…

2011

International audience

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

2009

Genetic plasticity of atrazine-degrader: evidence for the deletion of atzABC genes in pseudomonas sp. adp in response to cyanuric acid selection pres…

2010

International audience; Several bacterial strains are known to metabolize s-triazines herbicides among which atrazine reported worldwidel to contaminate soil and water resources. The complete mineralization of atrazine to carbon dioxide and ammonium is catalyzed by 6 hydrolytic enzymes encoded by atzABCDEF genes located on the plasmid pADP1 in Pseudomonas ADP. The atzABC genes code for the upper pathway transforming atrazine to cyanuric acid, while the atzDEF genes code for the lower pathway transforming cyanuric acid to simple compounds. In order to study the genetic plasticity of the atrazine catabolic pathway, we performed an in vitro evolution study consisting in applying a continuous s…

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

2007

International audience; Iron is an essential element for plants and microbes. However, in most cultivated soils, the concentration of iron available for these living organisms is very low since its solubility is controlled by stable hydroxides, oxyhydroxides and oxides. The high demand for iron by plants and microorganisms in the rhizosphere together with its low availability in soils leads to a strong competition for this nutrient among living organisms. To face this competition, plants and microorganisms have developed active strategies of iron uptake. In non graminaceous plants (strategy I), iron uptake relies on acidification and reduction of Fe+++ in Fe++ which incorporated in the root…

Evolution of the phenazine biosynthesis pathway and diversity of phenazine-producing Pseudomonas spp. in dryland wheat-producing areas of washington …

2009

Establishment of tools for investigating pyoverdine impact on iron homeostasis and plant defense responses

2013

Iron, the fourth major element in the Earth crust, is essential for growth and development of living organisms. However, due to its low solubility in the soil, it is weakly available for plants and micro-organisms. To efficiently assimilate iron, living organisms have evolved specific strategies. In plants such as Arabidopsis thaliana three trans-membrane proteins are involved in iron assimilation while in bacteria such as Pseudomonas fluorescens iron is taken up from the soil thanks to molecules displaying high affinity for iron called siderophores. It has been recently shown that pyoverdine, the major siderophore of the beneficial bacterium Pseudomonas fluorescens, is assimilated by A. th…

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

2019

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…

Analysis of the role of nitric oxide (NO) in the cross‐regulation between immunity, growth and iron homeostasis in plants

2019

Studies performed in our Agroecology Department show that the immune response of plants is linked to their iron nutrition and is modulated by pyoverdine, a siderophore produced by the plant beneficial rhizobacteria Pseudomonas fluorescens C7R12. Accordingly, Arabidopsis thaliana plantlets exposed to iron deficiency and treated with pyoverdine in its iron non‐chelated structure (apo‐pyo) show an enhanced growth but a decreased immune response capacity. We hypothesize that nitric oxide (NO), a universal signaling molecule, is a key component of the regulation of the immune response in plants exposed to apo‐pyo and to the C7R12 strain. We checked by fluorescence microscopy that NO is actually …