6533b836fe1ef96bd12a116f

RESEARCH PRODUCT

Identification et caractérisation du récepteur à la flagelline (VvFLS2) et recherche du récepteur aux chito-oligosaccharides chez la vigne

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Pattern-recognition receptors (PRRs) play a key role in plant immunity by assuring recognition of microbe-associated molecular patterns (MAMPs), signature of microbial presence. MAMP perception constitutes the first layer of pathogen detection and activates defense mechanisms that aim to block the intruder. This study brings an insight into how grapevine (Vitis vinifera) perceives two MAMPs: the flagellin-derived flg22 peptide and chitin, which are conserved motifs occurring over the whole bacterial and fungal classes, respectively. This study analyzed MAMP-triggered early signaling events, defense gene expression and also the efficiency of elicited defense against gray mold and downy mildew diseases. These two MAMPs are active in grapevine suggesting that perception systems exist. So far, no PRR is known for this crop.Given the availability of grapevine genome, we could identify in silico putative grapevine receptors (VvFLS2, VvCERK1-3 and VvCEBiP1-2) that might function as PRRs for flg22 and chitin, respectively. Their functional characterization was firstly achieved by complementation assays in the corresponding A. thaliana mutants and, secondly, by a gene silencing strategy in grapevine.Our results permitted the identification of VvFLS2, the V. vinifera receptor for the bacterial flagellin. The function of VvFLS2 was demonstrated by restoring the flg22 responsiveness in the Arabidopsis fls2 null mutant. Thus, our work provides the first description of an active grapevine PRR-MAMP pair. We further compared VvFLS2 and the Arabidopsis receptor, AtFLS2, in their capability to perceive flagellin-derived flg22 epitopes from endophytic or pathogenic bacteria. Our data clearly show that VvFLS2 differentially recognizes flg22 from different bacteria and suggest that flagellin from the beneficial plant growth-promoting rhizobacteria (PGPR) Burkholderia phytofirmans has evolved to evade grapevine immune recognition system. We also obtained preliminary data on chitin sensing system in grapevine and show that VvCERK3 might be a functional ortholog of AtCERK1 by partly restoring the oxidative burst triggered by chitin in the Arabidopsis cerk1-2 mutant.