Expression of Genes Related with Defense Responses against Pathogen Infections in Vitis flexuosa

Induced defense responses are regulated through a network of signal transduction pathways. Major signal transduction pathways in plants include salicylic acid (SA)- and jasmonic acid (JA)-mediated signaling pathways. In this study, we attempted to identify potential resistance mechanisms/pathways in Vitis flexuosa and the interaction between resistance and resistance related genes of V. flexuosa and several pathogens. To accomplish this, we investigated transcriptional expression of genes in the SA- and JA-mediated pathway and in the flavonoid biosynthesis pathway in V. flexuosa that had been infected by Elsinoë ampelina, Botrytis cinerea, Colletotrichum acutatum, Erysiphe necator, and Rhizobium vitis using real-time polymerase chain reaction (PCR) analysis. Quantitative real-time PCR revealed that R and R-related genes in V. flexuosa induced defense responses through expression of genes in SA-pathway rather than in the JA-pathway, and R-related genes were more closely correlated with lignin and phytoalexin biosynthesis than anthocyanin biosynthesis against different pathogen infections in V. flexuosa. Specifically, genes such as VfRLK586, VfRLK2422, VfRLK5099, VfRLK29610, VfRLK55257, VfRPS5-like4135, VfRPS5-like4832, VfRPS5-like20585, VfRPS5-like55532, VfEDL2, VfEDL3, VfCXE5585, VfCXE12827, and VfCXE13132 showed close correlation with induction of genes in the SA-mediated pathway, lignin, phytoalexin, and anthocyanin biosynthesis. Genes including VfRLK2422, VfRLK5099, VfRLK29610, VfRPS5-like55532, VfEDL3, and VfCXE12827 were also correlated with the JA-mediated signaling pathway in induction of defense responses.