Grapevine LysM-containing receptor-like kinase VvLYK6 enhances resistance to white rot in tomato

Grapevine (Vitis vinifera) is a fruit that is widely cultivated worldwide, but white rot, caused by Coniella vitis, significantly impacts its yield and quality. The lack of resistance genes poses a major challenge to breeding grapevine varieties resistant to white rot. The LysM-containing receptor-like kinase (LYK) family genes are known to mediate immune responses to pathogens by recognizing pathogen-associated molecular patterns. To explore the resistance genes underlying white rot resistance, whole-transcriptome sequencing was carried out on grapevine cv. Guifeimeigui (GF, resistant phenotype) and cv. Red Globe (RG, susceptible phenotype) after challenge with C. vitis. Functional characterization and mechanistic analysis were conducted through virus-induced gene silencing (VIGS) in grapevine, stable overexpression in grapevine calli, and heterologous expression in tomato (Solanum lycopersicum). Differentially expressed genes (DEGs) enriched in the "Plant-pathogen interaction" pathway were identified, followed by expression clustering analysis to pinpoint 14 candidate genes. Silencing of VvLYK6 in GF resulted in a significant reduction in resistance to white rot, while its overexpression in grapevine calli inhibited the growth of C. vitis. VvLYK6 is localized to the cell membrane. SlLYK1 was involved in the resistance to C. vitis in tomato that was mediated by VvLYK6. The overexpression of VvLYK6 in tomato also activated the salicylic acid signaling pathway and upregulated related pathogenesis-related genes, moreover induced a burst of reactive oxygen species, thereby increasing resistance to white rot. This study identifies VvLYK6 as a critical regulator of white rot resistance, and reveals its immune mechanism, and highlights its potential as a target for breeding and genetic improvement of durable resistance in grapevine.