鲜食葡萄果实发育过程中有机酸积累差异研究

Study on Differences of Organic Acid Accumulation during Fruit Development of Table Grape

为探究鲜食葡萄果实有机酸含量的积累规律,以‘阳光玫瑰’‘巨峰’‘意大利’和‘摩尔多瓦’4个品种为试材,对果实发育期的有机酸含量、有机酸代谢酶活性及相关基因表达量进行分析。结果表明,果实发育过程中有机酸含量呈逐渐下降趋势,成熟时总有机酸含量在品种间存在差异,由高到低依次为巨峰(8.31 mg·g^(-1))>摩尔多瓦(7.80 mg·g^(-1))>意大利(7.48 mg·g^(-1))>阳光玫瑰(6.62 mg·g^(-1))。酸种类中以酒石酸含量最高(5.17~6.19 mg·g^(-1)),其次为苹果酸(0.72~1.81 mg·g^(-1)),柠檬酸含量最低(0.20~0.94 mg·g^(-1))。不同品种间苹果酸酶(NADP-ME)、苹果酸脱氢酶(NAD-MDH)、柠檬酸合成酶(CS)活性及VvME、VvMDH基因表达量差异显著。苹果酸含量与NADP-ME活性呈显著负相关,与NAD-MDH活性呈显著正相关;柠檬酸含量与CS活性呈极显著正相关,‘意大利’和‘摩尔多瓦’葡萄果实柠檬酸含量与线粒体-顺乌头酸酶(Mit-ACO)活性呈极显著负相关。4个鲜食葡萄果实苹果酸与柠檬酸积累差异主要由VvME、VvMDH基因的差异表达及NADP-ME、NAD-MDH、CS和Mit-ACO酶活性差异所致。

In order to explore the accumulation rule of organic acid content in table grape fruits,table grape varieties‘Shine Muscat’‘Kyoho’‘Italy’and‘Moldova’were used to investigate the content of organic acids,organic acid metabolism enzyme activity,and related gene expression during fruit development.The results showed that the content of organic acids gradually decreased during the fruit development process,and there were differences in total organic acid content among varieties during fruit ripening.From high to low in order,that were Kyoho(8.31 mg·g^(-1))>Moldova(7.80 mg·g^(-1))>Italy(7.48 mg·g^(-1))>Shine Muscat(6.62 mg·g^(-1)).Among the acids,tartaric acid was the highest content(5.17-6.19 mg·g^(-1)),followed by malic acid(0.72-1.81 mg·g^(-1)),and citric acid was the lowest content(0.20-0.94 mg·g^(-1)).The activities of malic acid dehydrogenase(NADMDH),malate dehydrogenase(NAD-MDH),citrate synthase(CS)and expression of VvME,VvMDH genes were significantly different among the varieties.Correlation analysis showed that the content of malic acid was negatively correlated with NADP-ME activity,and positively correlated with NAD-MDH activity.Citric acid content was significantly positively correlated with CS activity.Citric acid content in‘Italy’and‘Moldova’grape fruits were significantly negatively correlated with mitochondrial aconitase(Mit-ACO)activity.The difference of malic acid and citric acid accumulation in four varieties was mainly caused by the differential expression of VvME,VvMDH genes,as well as differences in NADP-ME,NAD-MDH,CS and Mit-AC O enzyme activities.