Burdock fructooligosaccharides inhibits postharvest colour development in grape skins by altering phenylpropanoid fluxes from anthocyanin to the resistance-related phenolic substances

Background and Aims Burdock fructooligosaccharides (BFO) is an elicitor that induces biotic resistance and delays colour development in grapes postharvest. The mechanism of the delayed colour development requires further study. Methods and Results Colour development index; anthocyanin, tannin, flavonol, flavanol, trans -resveratrol and lignin; the trans -resveratrol, lignin and anthocyanin biosynthesis-related transcription factors; and functional gene expression were investigated. In response to BFO induction, upregulation of the v-myb avian myeloblastosis viral oncogene homologue 14 ( MYB14 )-mediated stilbene synthase ( STS ) altered the phenylpropanoid fluxes from anthocyanin to trans -resveratrol; MYBA1 and MYBA2- mediated the downregulation of dihydroflavonol 4-reductase ( DFR ), and flavonoid-3-O-glycosyltransferase ( UFGT ) limited anthocyanin biosynthesis. Downregulation of MYB4- mediated chalcone synthase ( CHS ) and upregulation of cinnamoyl CoA reductase ( CCR ) and cinnamyl alcohol dehydrogenase ( CAD ) altered the phenylpropanoid fluxes from anthocyanin to lignin. Conclusions Burdock fructooligosaccharides inhibits postharvest colour development in grapes by altering the phenylpropanoid fluxes from anthocyanin to resistance-related phenolic substances. Significance of the Study Understanding the mechanism of the effect of BFO on grape colour development may improve our understanding of colour development in grape berries.