Plasmopara viticola effector PvRXLR159 suppresses immune responses in Nicotiana benthamiana

Plasmopara viticola, the causal oomycete of grapevine downy mildew disease, secrets a series of RXLR effectors to manipulate host immunity. In this study, we characterized the role of a RXLR effector of P. viticola, PvRXLR159, in plant–microbe interaction. Transcription of PvRXLR159 in P. viticola was induced in the early stage of infection in grapevine (Vitis vinifera ‘Thomson Seedless’). Further results revealed that PvRXLR159 contains a functional signal peptide and its C terminus was essential to inhibit cell death by elicitors, INF1 and BAX, in Nicotiana benthamiana. Transient expression of PvRXLR159 suppressed N. benthamiana resistance to a pathogenic oomycete, Phytophthora capsici. Taken together, we propose that PvRXLR159 is induced and secreted by P. viticola to suppress host resistance.