Effect Of Exogenous Brassinolides Treatment On Sugar Metabolism And Anthocyanin Synthesis Of Merlot Grape Berries

Sugar is a key factor in determining the quality of grapes and wine.In actual production,the quality of wine grapes can be adjusted by spraying with exogenous growth regulators to obtain high-quality wine.In this study,"Merlot" was used as the test material,and different concentrations of EBR(0.2,0.4,0.6 mg/L)solutions were sprayed in the eighth week after anthesis,and with distilled water as a control to study the sugar metabolism and fruit quality of"Merlot" grape berries in order to screen out the suitable concentration for the growth of'Merlot'grapes.It will provide a scientific theoretical basis for the application of EBR to regulate fruit quality in production.The results of this study are as follows:(1)The effect of EBR treatment on the sugar components during the development of Merlot grape fruit.Compared with the control,0.6 mg/L EBR treatment can significantly promote the accumulation of glucose and fructose in berries,the contents were increased by 16.95%and 39.3%,respectively.(2)The effect of EBR treatment on the activities of enzymes related to sugar metabolism in Merlot.T2 and T3 increased the activities of AI and SS in the early stage of fruit ripening.At maturation,the activities of AI and SPS were significantly higher than control.Correlation analysis showed that the accumulation of glucose and fructose in the fruit was related to SS and AI,and 0.6 mg/L EBR treatment increased the correlation between hexose and the two enzymes(significant positive correlation).(3)The effect of EBR treatment on genes related to sugar metabolism during the ripening of Merlot grapes.During fruit development,VvSS always showed a high expression pattern while VvSPS was low.0.6mg/L EBR treatment could induce SS gene expression,and its relative expression was 2.75 times that of control;0.4 mg/L EBR treatment during veraison significantly increased the expression of VvcwINV,and 0.6 mg/L EBR significantly increased the transcription level of VvcwINV and VvSUC12 during the process of fruit color transformation to maturity.(4)The effect of EBR treatment on anthocyanins during fruit development.Dimethylanthocyanin(Mv)are dominent in the peel of Merlot grapes,which accounts for about 55%of the total during the maturity period;the 0.4 and 0.6 mg/LEBR treatments significantly increased the Mv content.The 0.2 and 0.4 mg/L EBR treatments significantly up-regulated the transcriptional expression of VvDFR,VvUFGT and VvMYBA1 genes at the early stage of veraison,while the 0.6 mg/L EBR treatment up-regulated the transcriptional expression of VvCHSl,VvDFR,VvUFGT and the regulatory gene VvMYBA1 during the entire fruit ripening period.(5)The effect of EBR treatment on the quality of Merlot grapes.Three concentrations of EBR treatment(0.2,0.4,0.6 mg/L)all reduced the titrated acid content and increased the soluble solids,total phenol,tannin and anthocyanin content of the fruit during maturity,of which the optimal concentration was 0.6 mg/L.