Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650, China.
BMC Plant Biol. 2021 Jan 6;21(1):21. doi: 10.1186/s12870-020-02811-8.
DNA methylation is a conserved and important epigenetic modification involved in the regulation of numerous biological processes, including plant development, secondary metabolism, and response to stresses. However, no information is available regarding the identification of cytosine-5 DNA methyltransferase (C5-MTase) and DNA demethylase (dMTase) genes in the orchid Dendrobium officinale.
In this study, we performed a genome-wide analysis of DoC5-MTase and DodMTase gene families in D. officinale. Integrated analysis of conserved motifs, gene structures and phylogenetic analysis showed that eight DoC5-MTases were divided into four subfamilies (DoCMT, DoDNMT, DoDRM, DoMET) while three DodMTases were divided into two subfamilies (DoDML3, DoROS1). Multiple cis-acting elements, especially stress-responsive and hormone-responsive ones, were found in the promoter region of DoC5-MTase and DodMTase genes. Furthermore, we investigated the expression profiles of DoC5-MTase and DodMTase in 10 different tissues, as well as their transcript abundance under abiotic stresses (cold and drought) and at the seedling stage, in protocorm-like bodies, shoots, and plantlets. Interestingly, most DoC5-MTases were downregulated whereas DodMTases were upregulated by cold stress. At the seedling stage, DoC5-MTase expression decreased as growth proceeded, but DodMTase expression increased.
These results provide a basis for elucidating the role of DoC5-MTase and DodMTase in secondary metabolite production and responses to abiotic stresses in D. officinale.
DNA 甲基化是一种保守且重要的表观遗传修饰，参与调控许多生物学过程，包括植物发育、次生代谢和对胁迫的响应。然而，关于兰花铁皮石斛中胞嘧啶-5 型 DNA 甲基转移酶（C5-MTase）和 DNA 去甲基化酶（dMTase）基因的鉴定信息尚不清楚。
本研究在铁皮石斛中进行了 DoC5-MTase 和 DodMTase 基因家族的全基因组分析。保守基序、基因结构和系统发育分析的综合分析表明，8 个 DoC5-MTase 分为四个亚家族（DoCMT、DoDNMT、DoDRM、DoMET），而 3 个 DodMTase 分为两个亚家族（DoDML3、DoROS1）。在 DoC5-MTase 和 DodMTase 基因的启动子区域发现了多个顺式作用元件，特别是应激和激素响应元件。此外，我们研究了 10 种不同组织中 DoC5-MTase 和 DodMTase 的表达谱，以及在幼苗阶段、原球茎体、芽和小植株中在非生物胁迫（冷和干旱）下的转录丰度。有趣的是，大多数 DoC5-MTase 受到冷胁迫下调，而 DodMTase 则被上调。在幼苗阶段，随着生长的进行，DoC5-MTase 的表达减少，但 DodMTase 的表达增加。
这些结果为阐明 DoC5-MTase 和 DodMTase 在铁皮石斛次生代谢产物产生和对非生物胁迫响应中的作用提供了依据。
