Molecular Characterization and Overexpression of VpRPW8s from Vitis pseudoreticulata Enhances Resistance to Phytophthora capsici in Nicotiana benthamiana.

RPW8 genes are atypical broad-spectrum genes that provide resistance to powdery mildew, downy mildew, the cauliflower mosaic virus in Arabidopsis thaliana , and powdery mildew in tobacco. They play important roles in basal plant pathogen defense. They also provide insights into a novel disease resistance mechanism. In this study, we report on homologous RPW8 genes in Vitis pseudoreticulata. Five VpRPW8 genes were cloned; their Open Reading Frame (ORF) sequences ranged from 1994 base pairs to 2478 base pairs. They were comprised of five exons and four introns and shared 78.66% identity. Their proteins had typical conserved RPW8 and NB-LRR (the nucleotide-binding site and the leucine-rich repeats) domains (except VpRPW8-d, which lacked LRR domains). Prokaryotic expression results were consistent with predicted molecular weights. All five RPW8 genes were located in the cytoplasm. Quantitative real-time PCR (qRT-PCR) analysis showed that VpRPW8s in V. pseudoreticulata were induced by Plasmopara viticola , but nearly only VvRPW8-d genes were induced in Vitis vinifera. Furthermore, a VpRPW8 transgenic tobacco system was established. Overexpressed VpRPW8s enhanced resistance to Phytophthora capsici and VpRPW8s conferred varying degrees of resistance to Ph. capsici in Nicotiana benthamiana . Our study presents novel members of the plant RPW8 family and suggests that VpRPW8s are involved in enhanced resistance to P. viticola and Ph. capsici .