Abstract:

To study the effects of 2,4-Epibrassinolide（EBR）on anthocyanin synthesis and berry quality under high temperature stress，Vitis vinifera L.‘Cabernet Sauvignon’were used as the material. Before veraison，grapevines were sprayed with EBR and conducted the heat stress experiments，which simulated by the infrared radiator. Results indicated that the anthocyanin contents were reduced and the expression levels of the anthocyanin synthesis genes such as VvCHS，VvDFR，VvLDOX，and VvMybA1 were down-regulated after heat stress. At the beginning of veraison，compared with the control，the berry coloring rate was reduced by 17.80% after the high-temperature treatment. EBR treatments increased the contents of anthocyanin and soluble sugar in grape berry. The content of anthocyanins in high temperature with EBR treatment was increased by 21.65% compared with only the high temperature group at 77 d after anthesis. At the late ripening stage，the gene expression levels of VvCHS and VvLDOX in high temperature with EBR were 3.27 and 2.21 time folds of those in the high temperature group. Further analysis showed that the content of anthocyanins was significant positively correlated with the transcription level of VvMybA1 under the high temperature + EBR treatment. Moreover，there is a positive correlation relationship between sugar and anthocyanin. In conclusion，the treatment with EBR could increase anthocyanin content，improve berry coloring，promote sugar and total phenols accumulation，and effectively alleviate the effect of high temperature on berry quality in‘Cabernet Sauvignon’.

Key words: grape, EBR, high temperature stress, anthocyanins, berry quality