Study On Sugar And Acid Accumulation,Metabolism Enzymes Activities And Gene Expression Of Two Chinese Cherry Fruits

The research investigated the accumulation of sugar and acid,related metabolic enzymes activities and expression of related enzyme genes during the development of “Heiyingtao” and “Hongyingtao”,and discovered the relationship among the accumulation of sugar and acid,the main enzymes and genes of related enzymes during the development of chinese cherry to provided a theoretical basis for the quality production of chinese cherries.The 10-year-old “Heiyingtao” and “Hongyingtao” planted in Hanyuan County were used as test materials to determine the content of sugar and acid components,the activity of sugar and acid metabolism-related enzymes and the expression of related enzyme genes during the developmental period.The results are as follows:1.The main accumulated sugar of the two chinese cherry fruits was glucose and fructose.The glucose content was highest when the fruit matures,accounting for 53% of the total sugar content.The fructose content accounted for 45% of total sugar content.The total sugar content of “Heiyingtao” was higher than that of “Hongyingtao”.2.The activities of SS-c and AI were higher than that of SPS and NI in the late stage of fruit development.The sucrose content was significantly negatively correlated with the activities of AI and SS-c,and was positively correlated with the activity of SPS.The SS-c and AI were the key enzyme for the accumulation of sugar in two chinese cherry fruits.The difference in sugar content was caused by the difference in the activities of the two enzymes between two chinese cherry fruits.3.The expression of three SS genes and AI gene were consistent with the trend of SS-c and AI activities after veraison in the development of two chinese cherry fruits;The expression of two SPS genes and NI gene were low in the late fruit development stage.The activities of SS-c and AI were positively regulated by SS3,SS6 and AI gene to promoted the accumulation of reducing sugar in the late stage of fruit development.4.The main accumulated acid of two chinese cherry fruits was malic acid.The malic acid content accounted for more than 85% of the total acid content when the fruit matures,and the other types of organic acids were lower.The total acid content of the “Hongyingtao” fruit was higher than that of “Heiyingtao”.5.The activities of NAD-MDH and PEPC was similar to the trend of malic acid content and was significantly positively correlated with malic acid content in two chinese cherry fruits.The activity of NADP-ME increased rapidly in the late stage of fruit development and was negatively correlated with malic acid content.The activity of CS was significantly positively correlated with citric acid content.The key enzymes in the organic acid metabolism of two chinese cherry fruits was NAD-MDH,NADP-ME and PEPC.The key factor leading to difference of malic acid content was the difference of three enzyme activities in two cherry fruits.6.The trend of MDH,PEPC and ME expression were opposite to the activities of NAD-MDH,PEPC and NADP-ME in the two chinese cherry fruits during the developmental period.MDH,PEPC and ME genes regulated the accumulation of malic acid by negatively regulating the activities of NAD-MDH,PEPC and NADP-ME in the late stage of two chinese cherries development.