Identification of key genes regulating the synthesis of quercetin derivatives in Rosa roxburghii through integrated transcriptomics and metabolomics1

Rosa roxburghii fruit is rich in flavonoids, but little is known about their biosynthetic pathways. In this study, we employed transcriptomics and metabolomics to study changes related to flavonoids at five different stages of R. roxburghii fruit development. Flavonoids and genes related to their biosynthesis were found to undergo significant changes in abundance across different developmental stages, and a large number of quercetin derivatives were identified. We found three gene expression modules that were significantly associated with the abundance of different flavonoids in R. roxburghii and identified three structural UDP-glycosyltransferase genes directly involved in the synthesis of quercetin derivatives within these modules. In addition, we found that RrBEH4, RrLBD1 and RrPIF8 could significantly increase the expression of downstream quercetin derivatives biosynthesis genes. Taken together, these results provide new insights into the metabolism of flavonoids and the accumulation of quercetin derivatives in R. roxburghii.