Comparative transcriptomic and metabonomic analysis revealed the relationships between biosynthesis of volatiles and flavonoid metabolites in Rosa rugosa

Rosa rugosa is not only cultivated as a landscaping plant, but also used in cosmetics, the medical and food industries. However, little information is currently available on the gene regulatory networks involved in its scent and color biosynthesis and metabolism. In this study, R. rugosa Thunb. f. rosea Rehd with red petals (RR) and its white petal variant (WR), were used to study the molecular mechanisms in flower color and scent. Sixty-five differential flavonoid metabolites and 15 volatiles were found to have significant differences between RR and WR. Correspondingly, the key regulators (MYB-bHLH-WD40) of anthocyanin synthesis pathway and their structural genes involved in flavonoid biosynthesis, benzenoid/phenylpropanoid biosynthesis, terpenoid biosynthesis pathways were also found to be differentially expressed by comparative transcriptome. Further, qPCR permitted the identification of some transcripts encoding proteins that were putatively associated with scent and color biosynthesis in roses. Particularly, the results showed that the ACT gene (encoding CoA geraniol/citronellol acetyltransferase, GeneID: 112190420), which expressed lower in WR, was involved in three pathways: flavonoid biosynthesis, phenylpropanoid biosynthesis and terpenoid biosynthesis, however, GT5 (anthocyanin glycosylation gene, GeneID:112186660), expressed higher in WR, was involved in both flavonoid and phenylpropanoid biosynthesis pathways. These results suggested that ACT and GT5 might play important roles in regulating the relationship of color pigmentation and volatile emission.