Effects Of Different Rootstocks On Organic Acid Metabolism In Cabernet Sauvignon Fruit

The type and content of organic acids in grape fruit determine the quality and sensory quality of wine and have an extremely important impact on production.In the actual production of wine grapes,people generally use different combinations of rootstocks and scions to regulate the internal microenvironment of grape growth and improve the quality of wine grapes,so as to obtain high-quality wine grapes suitable for production and processing.In this study,cabernet sauvignon 169 grafted on different rootstocks was used as the experimental material to determine the content of organic acids,the activities of enzymes related to acid metabolism and the expression of related genes in fruits under the interaction of five combinations of rootstocks and panicles,explore the law of action of the main types and contents of organic acids in fruits,and reveal the changing trends of the content of organic acids in fruits of different combinations of rootstocks and panicles,in order to provide a theoretical basis for solving a series of problems caused by "high sugar and low acid" in the production practice in xinjiang region.In this study,the combination of perennial Cabernet Sauvignon rootstock and spike was used as the test material,including CS169/110 R,CS169/3309 C,CS169/SO4,CS169/ Kangzhen No.3 and Cabernet Sauvignon self-rooted seedling(CK).The contents of organic acids(oxalic acid,tartaric acid,malic acid,citric acid and succinic acid)in grape fruits at different stages were determined by high performance liquid chromatography,the activities of related enzymes(NAD-MDH,NADP-ME,CS,PEPC)were determined by spectrophotometry,and the expression levels of related genes were determined by real-time fluorescence quantitative method.The results were as follows:(1)Effect of 6-year-old Cabernet Sauvignon on organic acid metabolism in different stages on different rootstocks.The results showed that the contents of tartaric acid and malic acid accounted for the main parts of organic acid content in the whole fruit growth and development process,and their content changes gradually decreased with the berry maturation,and there were significant differences between the anvil-spike combinations.CS169/110 R,CS169/SO4 and CS/ kangzhen No.3 could significantly increase the content of malic acid in fruits.the combination of CS169/3309 C rootstock and ear had little effect on the content of malic acid in fruits,but the content changed greatly,with the change amplitude reaching73.40%.CS169/110 R,CS169/3309 C,CS169/SO4 and CS/Kangzhen No.3 could significantly reduce the content of tartaric acid in fruits.Oxalic acid,citric acid,succinic acid and other contents accounted for relatively small proportion of organic acid contents in each fruit.CS169/110 R,CS169/3309 C,CS169/SO4 and CS/Kangzhen No.3 could significantly reduce the contents of oxalic acid and citric acid,but all could significantly increase the organic acid content of succinic acid in fruits.(2)Effects of different rootstocks on the activities of organic acid metabolizing enzymes in6-year-old Cabernet Sauvignon fruits at different stages.The results showed that NAD-MDH enzyme activity and PEPC enzyme activity were related to malic acid synthesis,but PEPC enzyme activity was easily affected when the acid content in the fruits was high.The activity of NADP-ME is related to promoting the degradation of malic acid.CS enzyme activity has a significant influence on citric acid content in the early stage of fruit growth and development,but there is a difference between CS enzyme activity and citric acid content in the late stage of fruit growth and development.(3)According to the dynamic changes of NAD-MDH,NADP-ME and PEPC gene expression in6-year-old Cabernet Sauvignon fruit at different stages,it was found that NAD-MDH,NADP-ME and PEPC genes were related to the synthesis of malic acid,and the changes of NAD-MDH gene and its corresponding enzyme activity were consistent,and the NADP-ME enzyme activity and PEPC enzyme activity were easily influenced by other factors,so their genes were corresponding.