Abstract: Long non-coding RNAs (lncRNAs) play an important role in regulating plant growth and development, and stress response. However, their roles in Botrytis cinerea resistance remain poorly characterized. As a devastating necrotrophic fungus, gray mold is one of the most serious diseases that affects crop production worldwide. In this study, through screening of B. cinerea resistance in 18 strawberry germplasms, we identified Fragaria nilgerrensis as a resistant species and Fragaria nubicola as a susceptible one. We conducted lncRNA-seq on resistant and susceptible strawberries at 4 d after B. cinerea inoculation and untreated controls. lincRNA6679 and its target gene FnWRKY14 were identified in F. nilgerrensis. Coding potential assessment and RNA pull-down experiments revealed that lincRNA6679 is a long non-coding RNA that positively regulates FnWRKY14 expression by forming molecular complexes with FnWRKY50 or FnMYB59. Genetic transformation demonstrated that both lincRNA6679 and FnWRKY14 enhance resistance to B. cinerea in strawberries. Moreover, FnWRKY14 is bound to the FnPR1B promoter, activating its expression. FnWRKY14 was phosphorylated and activated by FnMAPK3 or FnMAPK6, further upregulating the expression of FnPR1B and enhancing disease resistance. This study revealed how long non-coding RNAs regulate strawberry resistance to B. cinerea, broadening the scope of research on strawberry resistance mechanisms and providing new strategies for molecular breeding.

Key words: Botrytis cinerea, lncRNA, phosphorylation, strawberry, transcriptional regulation