6533b7d3fe1ef96bd1260788

RESEARCH PRODUCT

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

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description

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. thaliana through an unknown mechanism. Interestingly, pyoverdine improves plant growth and iron nutrition. It is currently accepted that iron competition is a key event during plant infection by pathogenic micro-organisms. Furthermore, a protective role conferred to plants by several beneficial bacteriosiderophores against pathogens has been proposed. To investigate the global incidence of pyoverdine on plants, we decided to perform a microarray analysis. We identified plant genes whose expression is highly modulated by pyoverdine. These genes mainly encode proteins involved in iron homeostasis and in defense reactions. Further work will include pathogenicity tests using mutants affected in the expression of the genes of interest to understand their role in pyoverdine effects. These set of data will give us a first view of the incidence of pyoverdine in the plant physiology and its capacity to face pathogen attack.