乌龙茶加工过程中乙醇脱氢酶ADH及其相关基因在C6醛-C6醇转化过程
2020-01-07 作者: admin 来源: 未知 已阅读次
香气是茶叶品质的重要指标之一。茶叶脂类中由亚油酸（LA）和亚麻酸（ALA）形成的挥发性C6化合物是茶香气的基本成分。以LA、ALA为代表的不饱和脂肪酸，在脂肪氧合酶-氢过氧化物裂解酶（LOX-HPL）途径的氧化裂解下，形成具有青草气的挥发性C6醛类，该物质在乙醇脱氢酶（ADH）作用下发生转化，形成具有清香的脂肪族C6醇类和弥散果香的脂肪酯类，同时C6的及时转化也可避免茶叶贮藏过程中“返青”现象的产生。本文基于GC-MS技术对乌龙茶加工过程中C6醛和醇的检测，通过茶树基因组数据库筛选获得了1条潜在的关键ADH基因。
Abstract
Aroma is an important index of tea quality. The volatile C6‐compounds formed from linoleic and linolenic acids in tea leaf lipids are essential components of tea. C6‐compounds are formed and transformed during the postharvest process of tea leaves. However, the metabolic flux of these C6‐compounds, the activities of related enzymes, and the transcription of related genes during the postharvest process of oolong tea remain unclear. In this study, the chemical profiles of C6‐aldehydes and C6‐alcohols, the pattern of ADH enzyme activity, and the level of CsADH gene expression during the postharvest process of oolong tea were investigated. We found that the turnover process had a positive effect on the accumulation of C6‐alcohols and simultaneously induced ADH activity, especially during the withering stage. The expression of CsADHpeaked during the turnover stage. The relative expression level of CSA019598 typically increased during the postharvest process. Correlation analysis demonstrated that CSA019598 expression increased as ADH activity increased. This finding suggests that CSA019598 may play a prominent role in regulating ADH. These results advance our understanding of C6‐compound formation during the postharvest process of oolong tea. We aim to evaluate how green leaf volatiles affect the enzymatic formation and genetic transcription of aromatic compounds in oolong tea in future studies.
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