Vernalization, influenced by environmental factors, is an essential process associated with the productivity of temperate crops, during which epigenetic regulation of gene expression plays an important role. Although DNA methylation is one of the major epigenetic mechanisms associated with the control of gene expression, global changes in DNA methylation in the regulation of gene expression during vernalization-induced flowering of temperate plants remain largely undetermined. To characterize vernalization-associated DNA methylation dynamics, we performed whole-genome bisulfite-treated sequencing and transcriptome sequencing in orchardgrass (Dactylis glomerata) during vernalization. The results revealed that increased levels of genome DNA methylation during the early vernalization of orchardgrass were associated with transcriptional changes in DNA methyltransferase and demethylase genes. Upregulated expression of vernalization-related genes during early vernalization was attributable to an increase in mCHH in the promoter regions of these genes. Application of an exogenous DNA methylation accelerator or overexpression of orchardgrass NUCLEAR POLY(A) POLYMERASE (DgPAPS4) promoted earlier flowering, indicating that DNA hypermethylation plays an important role in vernalization-induced flowering. Collectively, our findings revealed that vernalization-induced hypermethylation is responsible for floral primordium initiation and development. These observations provide a theoretical foundation for further studies on the molecular mechanisms underlying the control of vernalization in temperate grasses.

中文翻译：

---

DNA高甲基化促进了春化过程中果园的开花。

受环境因素影响的春化是与温带作物生产力相关的重要过程，在此过程中基因表达的表观遗传调控发挥着重要作用。尽管 DNA 甲基化是与基因表达控制相关的主要表观遗传机制之一，但在春化诱导的温带植物开花期间，基因表达调控中 DNA 甲基化的全局变化在很大程度上仍未确定。为了表征与春化相关的 DNA 甲基化动力学，我们在春化期间对果园（Dactylis glomerata）进行了全基因组亚硫酸氢盐处理的测序和转录组测序。结果表明，果园早期春化过程中基因组DNA甲基化水平的增加与DNA甲基转移酶和去甲基化酶基因的转录变化有关。早春化期间春化相关基因的上调表达归因于这些基因的启动子区域中mCHH的增加。外源DNA甲基化促进剂的应用或果园核聚（A）聚合酶（DgPAPS4）的过表达促进了早期开花，表明DNA高甲基化在春化诱导的开花中起重要作用。总的来说，我们的研究结果表明，春化诱导的高甲基化是花原基起始和发育的原因。