Expression of structural genes related to anthocyanin biosynthesis of Vitis amurensis

Abstract

This research was designed to assess the changes in anthocyanin content in grape skins of Vitis amurensis and to explore mRNA transcriptions of 11 structural genes (PAL, CHS3, CHI1, F3H2, F3′H, F3′5′H, DFR, LDOX, UFGT, OMT and GST) related to anthocyanin biosynthesis during grape berry development, by the use of HPLC-MS/MS and real-time Q-PCR analysis. Accumulation of anthocyanins began at veraison, continued throughout the later berry development and reached a peak at maturity. Veraison is the time when the berries turn from green to purple. Expression of PAL, CHI1, and LDOX were up-regulated from 2 to 4 weeks after flowering (WAF), down-regulated from 6 WAF to veraison, whereas DFR was up-regulated at 8 WAF, and then up-regulated from veraison to maturity. CHS3, F3′5′H, UFGT, GST, and OMT were down-regulated from 2 WAF to veraison, and then up-regulated from veraison to maturity. The transcriptional expressions of the 11 structural genes also showed positive correlations with the anthocyanin content from veraison to maturity. Positive correlations were also observed between OMT transcriptional level and the content of methoxyl-anthocyanins, and between F3′5′H transcriptional level and the content of delphinidin anthocyanins. F3H2 and F3′H expression was up-regulated at 2 WAF. F3H2 expression was down-regulated from 4 WAF to veraison and then up-regulated again from veraison to maturity. F3′H expression was down-regulated at 4 WAF and then up-regulated again from 6 WAF to maturity. F3′H transcriptional level was correlated positively with the cyanidin anthocyanin concentration from veraison to maturity. These results indicate that the onset of anthocyanin synthesis during berry development coincides with a coordinated increase in the expression of a number of genes in the anthocyanin biosynthetic pathway.