Establishment of a novel system to elucidate the mechanisms underlying light-induced ripening of strawberry fruit with an Agrobacterium-mediated RNAi technique

Traditional methods used to study strawberry ripening-related gene function are time-consuming, and require at least 15 months from initiating the transformation experiment until therst ripe fruits are available for analysis. To accelerate data acquisition during gene function studies, we explored a transient assay method that employs an Agrobacterium-mediated RNAi (AmRNAi) technique in post-harvest strawberry fruit, Fragaria×ananassa (Fa) cv. Sachinoka, a Japanese cultivar. Our results showed that articial white light induced strong expression of F achalcone synthase (FaCHS), Fachalcone isomerase (FaCHI), and Fa��avonoid 3�-hydroxylase orthologues (FaF3�H) in post-harvest fruit. FaCHS and FaF3�H function was subsequently examined by performing AmRNAi with post-harvest fruit. Although reduction of light-induced FaF3�H expression by AmRNAi resulted in no signicant change in anthocyanin content, r eduction of FaCHS signicantly decreased anthocyanin levels, and up-regulated FaF3�H levels. Our results are consistent with previous data indicating that while CHS is required for anthocyanin accumulation during late stage strawberry fruit maturation, FaF3�H is not required. �e novel system described here enabled gene function data to be available within 10 days of initiating the incubation period following inltration. �erefore, we conclude our system is a valuable tool to e lucidate the molecular mechanisms underlying light-induced ripening of strawberry fruit.