The Analysis Of VvHY5 And VvCOP1 At Transcription And Protein Level In Grape Skins With Sunlight Exclusion

The color of grape berry skin was determined by the composition and content of anthocyanins. It is one of the most important quality traits, and greatly affects the economic value of table grapes as well as wine and juice. Light is one of the important factors that influence the biosynthesis of anthocyanins. In this study, some clusters of two red grape cultivars’Jingxiu’(Vitis Vinifera) and ’Jingyan’(V Vinifera,’Jingxiu’X white grape’Xiangfei’) were excluded from sunlight from fruit set until maturity (treatment), and some grew under natural condition (control). At maturity,’Jingxiu’ berry skin with treatment failed to color, which indicates that the biosynthesis of anthocyanins in’Jingxiu’berry skin was induced by light, and was sunlight-dependent. In contrast,’Jingyan’berry skin with treatment still developed red color, and was sunlight-independent. The aim of this study was to gain insight into the role of VvHY5 and VvCOPl in anthocyanins biosynthesis in sunlight-independent’Jingyan’.Via Real-Time PCR, the transcriptional expression patterns of VvCOPl and VvHY5 in sunlight-dependent’Jingxiu’and sunlight-independent ’Jingyan’ berry skin were found to be consistent, i.e. from fruit set to maturity VvCOPl and VvHY5 transcriptional expression tended to increase, and then decreased towards maturity; VvCOP1 transcriptional expressions did not show significant difference between control and treatment; VvHY5 transcriptional expression significantly decreased after treatment. The responses of VvCOPl transcriptional expression to natural day and night were similar between sunlight-dependent ’Jingxiu’ and sunlight-independent ’Jingyan’ berry skin, so were VvHY5. VvCOPl transcriptional expression did not significantly differ between natural day and night, and VvHY5 transcriptional expression significantly reduced at mid-night. It indicated that transcriptional expressions of VvCOPl and VvHY5 may not play a role in anthocyanins biosynthesis of sunlight-independent ’Jingyan’ berry skin under sunlight exclusion condition.Western blotting showed that VvCOPl proteins were detected in the berry skin of both ’Jingxiu’ and ’Jingyan’ whether with or without light, while a slight decrease occured in ’Jingyan’ without light. Further immunohistochemistry (IHC) showed the subcellular localization of VvCOPl proteins:Under sunlight, VvCOP1 proteins were found to mainly locate in the cytoplasm in both ’Jingxiu’ and ’Jingyan’; under sunlight-exlusion condition, VvCOPl proteins manily existed in the nuclear in ’Jingxiu’ while still distributed in the cytoplasm in’Jingyan’. It suggested that the nucleocytoplasmic transport of VvCOPl proteins may play an important role in anthocyanins biosynthesis of sunlight-independent ’Jingyan’ berry skin under sunlight exclusion condition.