Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA.
Int J Mol Sci. 2021 Sep 7;22(18):9681. doi: 10.3390/ijms22189681.
DNA methylation and demethylation precisely and effectively modulate gene expression during plant growth and development and in response to stress. However, expression profiles of genes involved in DNA methylation and demethylation during plant development and their responses to phytohormone treatments remain largely unknown. We characterized the spatiotemporal expression patterns of genes involved in de novo methylation, methyl maintenance, and active demethylation in roots, shoots, and reproductive organs using β-glucuronidase (GUS) reporter lines. Promoters of DNA demethylases were generally more highly active at the mature root tissues, whereas the promoters of genes involved in DNA methylation were more highly active at fast-growing root tissues. The promoter activity also implies that methylation status in shoot apex, leaf primordia, floral organs, and developing embryos is under tight equilibrium through the activity of genes involved in DNA methylation and demethylation. The promoter activity of DNA methylation and demethylation-related genes in response to various phytohormone treatments revealed that phytohormones can alter DNA methylation status in specific and redundant ways. Overall, our results illustrate that DNA methylation and demethylation pathways act synergistically and antagonistically in various tissues and in response to phytohormone treatments and point to the existence of hormone-linked methylome regulation mechanisms that may contribute to tissue differentiation and development.
DNA 甲基化和去甲基化精确有效地调节植物生长发育过程中的基因表达，并对胁迫做出响应。然而，在植物发育过程中参与 DNA 甲基化和去甲基化的基因的表达谱及其对植物激素处理的响应仍知之甚少。我们使用β-葡萄糖醛酸酶（GUS）报告系，对根、茎和生殖器官中从头甲基化、甲基维持和活性去甲基化相关基因的时空表达模式进行了研究。DNA 去甲基酶的启动子通常在成熟的根组织中具有更高的活性，而参与 DNA 甲基化的基因的启动子在快速生长的根组织中具有更高的活性。启动子活性也表明，通过参与 DNA 甲基化和去甲基化的基因的活性，在茎尖、叶原基、花器官和发育中的胚胎中，甲基化状态处于紧密平衡之中。对各种植物激素处理的 DNA 甲基化和去甲基化相关基因的启动子活性的研究表明，植物激素可以以特定和冗余的方式改变 DNA 甲基化状态。总的来说，我们的结果表明，DNA 甲基化和去甲基化途径在各种组织中以及对植物激素处理的反应中协同和拮抗作用，并指出存在与激素相关的甲基组调控机制，这些机制可能有助于组织分化和发育。
