DNA methylation plays important roles in regulating gene expression during development. However, little is known about the influence of DNA methylation on secondary metabolism during leaf development in the tea plant (). In this study, we combined the methylome, transcriptome, and metabolome to investigate the dynamic changes in DNA methylation and its potential regulatory roles in secondary metabolite biosynthesis. In this study, the level of genomic DNA methylation increased as leaf development progressed from tender to old leaf. It additionally exhibited a similar distribution across the genomic background at the two distinct developmental stages studied. Notably, integrated analysis of transcriptomic and methylomic data showed that DNA hypermethylation primarily occurred in genes of the phenylpropanoid, flavonoid, and terpenoid biosynthesis pathways. The effect of methylation on transcription of these secondary metabolite biosynthesis genes was dependent on the location of methylation (i.e., in the promoter, gene or intergenic regions) and the sequence context (i.e., CpG, CHG, or CHH). Changes in the content of catechins and terpenoids were consistent with the changes in gene transcription and the methylation state of structural genes, such as (), (), and (). Our study provides valuable information for dissecting the effects of DNA methylation on regulation of genes involved in secondary metabolism during tea leaf development.

中文翻译：

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茶树 (Camellia sinensis) 叶片发育过程中儿茶素和萜类化合物生物合成的动态 DNA 甲基化修饰


DNA甲基化在发育过程中基因表达的调节中发挥着重要作用。然而，人们对 DNA 甲基化对茶树叶片发育过程中次生代谢的影响知之甚少。在本研究中，我们结合甲基化组、转录组和代谢组来研究DNA甲基化的动态变化及其在次生代谢物生物合成中的潜在调节作用。在这项研究中，基因组 DNA 甲基化水平随着叶片从嫩叶发育到老叶的过程而增加。它还在所研究的两个不同发育阶段的基因组背景中表现出类似的分布。值得注意的是，转录组和甲基组数据的综合分析表明，DNA 高甲基化主要发生在苯丙素、类黄酮和萜类生物合成途径的基因中。甲基化对这些次级代谢物生物合成基因转录的影响取决于甲基化的位置（即在启动子、基因或基因间区域中）和序列背景（即CpG、CHG或CHH）。儿茶素和萜类化合物含量的变化与基因转录和结构基因甲基化状态的变化一致，如()、()、()。我们的研究为剖析 DNA 甲基化对茶叶发育过程中次生代谢相关基因调控的影响提供了有价值的信息。