<i>Plasmopara viticola</i> effector PvRXLR159 suppresses immune responses in <i>Nicotiana benthamiana</i>

<i>Plasmopara viticola</i>, 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 <i>P. viticola</i>, PvRXLR159, in plant–microbe interaction. Transcription of <i>PvRXLR159</i> in <i>P. viticola</i> was induced in the early stage of infection in grapevine (<i>Vitis vinifera</i> ‘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 <i>Nicotiana benthamiana</i>. Transient expression of PvRXLR159 suppressed <i>N. benthamiana</i> resistance to a pathogenic oomycete, <i>Phytophthora capsici</i>. Taken together, we propose that PvRXLR159 is induced and secreted by <i>P. viticola</i> to suppress host resistance.