Transcriptome analysis reveals the mechanism of ‘ZhongShan-HongYu’ grape anthocyanin accumulation

Abstract

During the biosynthesis of anthocyanin, the protein encoding GST transports anthocyanins synthesized in the endoplasmic reticulum to the vesicle, resulting in plant coloration. ‘ZhongShan-HongYu’ (ZS-HY) is a new teinturier germplasm which accumulates anthocyanin in the skin and flesh of the fruit. However, the molecular mechanisms of the flesh coloration in ‘ZS-HY’ remains unclear. We analyzed the transcriptomic profiles of ‘ZS-HY’ and ‘Zico’ flesh (‘ZS-HY’ and ‘Zico’ have similar phenological periods) at 5, 6 and 7 days after anthesis (DAA) using RNA-sequencing technology. A total of 76.27 G of clean data were obtained from our RNA-seq. By analyzing the differentially expressed genes (DEGs) in the flesh, 212 genes potentially involved in anthocyanin biosynthesis were screened. Through further analysis of DEGs, the genes related to anthocyanin accumulation in grape flesh, including VvMYBA1 and VvGST4, were selected for gene function verification. Subcellular localization analysis revealed that VvMYBA1 and VvGST4 were located in cytoplasm and nucleus. The interaction between VvMYBA1 and VvGST4 was analyzed by yeast two-hybrid analysis and BiFC assay. Meanwhile, we found that VvMYBA1 can regulate the activity of VvGST4 promoter by binding with it. Our study provides a basis for the molecular mechanism of anthocyanin transport in grape.