Involvement of DNA methylation in regulating the accumulation of the aroma compound indole in tea (Camellia sinensis) leaves during postharvest processing
Involvement of DNA methylation in regulating the accumulation of the aroma compound indole in tea (Camellia sinensis) leaves during postharvest processing
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DNA甲基化参与调节茶树采后加工过程中香气化合物吲哚的积累
DOI：
10.1016/j.foodres.2021.110183
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发表时间：
2021-02-08
影响因子：
8.1
通讯作者：
Yang, Ziyin
中科院分区：
文献类型：
--
作者：
Yang, Jie;Zhou, Xiaochen;Yang, Ziyin
茶叶（Camellia sinensis），特别是乌龙茶的制造过程涉及多种采后胁迫。这些逆境能诱导许多重要的香气物质的形成和积累，如吲哚、吲哚乌龙茶的主要花香成分。然而，人们对香气物质形成的调控机制，尤其是表观遗传调控机制知之甚少。DNA甲基化是一种重要的表观遗传修饰。启动子序列DNA甲基化水平的变化可以调节胁迫条件下的基因表达。本研究以茶树叶片为材料，检测了连续伤害处理前后吲哚生物合成关键基因（色氨酸合成酶f1-亚基2，CsTSB 2）的DNA甲基化水平和组蛋白3赖氨酸9二甲基化水平的差异。结果表明，DNA甲基化水平的高低影响着DNA的基本螺旋能力。循环？螺旋家族转录因子CsMYC 2a与CsTSB 2的启动子结合。通过对乌龙茶加工过程中DNA甲基转移酶转录水平的分析，筛选出了参与调控次生代谢产物生物合成/积累的候选基因。结果表明，结构域重排甲基转移酶3，一种DNA甲基转移酶，参与了乌龙茶加工过程中吲哚形成的DNA甲基化调控。这是第一份关于DNA甲基化参与茶叶采后胁迫下香气物质形成调控的报告。
The manufacturing process of tea (Camellia sinensis), especially oolong tea, involves multiple postharvest stresses. These stresses can induce the formation and accumulation of many important aroma compounds, such as indole?a key floral aroma contributor of oolong tea. However, little is known about the regulation mechanisms of aroma compound formation, especially epigenetic regulation. DNA methylation is an important epigenetic modification. Changes in the DNA methylation levels of promoter sequences can regulate gene expression under stress conditions. In this study, the differences in DNA methylation levels and histone 3 lysine 9 dimethylation levels of indole key biosynthetic gene (tryptophan synthase fl-subunit 2, CsTSB2) were detected between untreated and continuous wounding treatment tea leaves. The results show that the DNA methylation levels affect the ability of the basic helix?loop?helix family transcription factor CsMYC2a to bind to the promoter of CsTSB2. Analyses of the transcript levels of DNA methyltransferases during oolong tea processing screened out candidate genes involved in the regulation of secondary metabolite product biosynthesis/accumulation. The results suggest that the domains rearranged methyltransferase 3, a DNA methyltransferase, is involved in the DNA methylation regulation of indole formation during the oolong tea manufacturing process. This is the first report on the involvement of DNA methylation in the regulation of aroma compound formation in tea leaves exposed to postharvest stresses.