A Rhamnolipid precursor triggers Induced Systemic Resistance in Arabidopsis

International audience; In their environment, plants are frequently challenged by pathogenic microorganisms. To deal with these pathogens, plants possess an arsenal of defence mechanisms, quickly activated following microorganism perception. This perception involves Microbe-Associated Molecular Patterns (MAMPs) that are recognized by plant cells through Pattern Recognition Receptors (PRRs) resulting in plant innate immunity (MTI, MAMP-Triggered Immunity). We previously showed in the laboratory that a natural rhamnolipids secretome (RLsec), produced by Pseudomonas aeruginosa, induce classical markers of plant immunity on Arabidopsis thaliana leaves and is highly effective on several plants to induce local resistance at the foliar level against phytopathogenic microorganisms 1, 2, 3. Among the RLsec constituents, the 3-hydroxydecanoic acid (3-OH-C10:0) synthesis precursor of rhamnolipids (RLs) was identified. The aim of this study is to determine if the 3-OH-C10:0 precursor of RLs is perceived by A. thaliana roots and if this perception triggers a systemic resistance against the necrotrophic fungus Botrytis cinerea.