The Vitis vinifera receptor VvLYK6 negatively regulates chitin-triggered immune responses and promotes fungal infections
Botrytis cinerea is recognized as one of the most damaging fungal pathogens affecting grapevine (Vitis vinifera), directly impacting both grape yield and wine quality. Identifying new genes involved in the interaction between V. vinifera and B. cinerea appears to be a promising strategy for enhancing grapevine resistance in future breeding programs. During pathogen infection, plasma membrane-localized pattern recognition receptors (PRRs) are responsible for detecting conserved microbe-associated molecular patterns (MAMPs). Among PRRs, members of the LysM receptor-like kinase family are well known to mediate the recognition of fungal MAMPs and triggering plant immune signaling pathways. Interestingly, a novel member of this receptor family, named VvLYK6, was identified in grapevine as the most highly upregulated during B. cinerea infection. To investigate the role of VvLYK6 in plant immunity, we conducted overexpression studies in Arabidopsis thaliana and grapevine cell suspensions. Overexpression of VvLYK6 led to a reduction in chitin-induced MAPK activation, decreased expression of defense-related genes, reduced callose deposition, and increased plant susceptibility to fungal pathogens in A. thaliana. Based on these findings, we conclude that VvLYK6 acts as a negatively regulator of chitin-triggered immune responses, suggesting its potential role as a susceptibility gene during fungal infections.