Transcriptomic analyses reveal light-regulated anthocyanin accumulation in ‘ZhongShan-HongYu’ grape berries

Abstract

Teinturier grapevine cultivars of grapevine (Vitis vinifera L.) are characterized by red pulp berries. A new teinturier germplasm ‘ZS-HY’, accumulates pigments in its pulp and peel. We observed that bagging treatment (without light) caused an obvious inhibition of anthocyanin accumulation in ‘ZS-HY’ berries. Under bag removal treatment (with light), the malvidin, cyanidin and delphinidin derivatives accumulated rapidly after the berries exposed to light. To further determine the transcriptional mechanism of light-regulated anthocyanin accumulation in ‘ZS-HY’, we performed RNA-sequencing (RNA-seq) on the berries under bagging treatment and bag removal treatment. Correlation between anthocyanin content, concentration and 741 up-regulated differentially expressed genes (DEGs) in transcriptomic data were analyzed by using weighted gene co-expression network analysis (WGCNA), which indicated that the up-regulated genes had a similar expression pattern to the change in anthocyanin. The expression of the VvHY5-like, VvUVR3 and VvBBX25 light-responsive factors; the VvMYBA1, VvMYB30 and VvbHLH61-like transcription factors (TFs); and the VvUDP86A1, VvGT5, VvGT1 and VvUFGT4-like structural genes was significantly increased, under bag removal treatment as compared with the expression levels observed in bagging treatment. The results showed that light plays a critical role in the anthocyanin accumulation of dyer's grapes and in other biological changes. Here, we provide a theoretical basis for the transcriptional regulatory network that operates during light response, which will further strengthen our understanding of the molecular mechanism of light-induced anthocyanin biosynthesis in teinturier grapes.