Abstract：
DNA demethylation is involved in the regulation of flowering in plants, yet the underlying molecular mechanisms remain largely unexplored. The RELEASE OF SILENCING 1 (ROS1) gene, encoding a DNA demethyltransferase, plays key roles in many developmental processes. In this study, the ROS1 gene was isolated from Chrysanthemum lavandulifolium, where it was strongly expressed in the leaves, buds and flowers. Overexpression of the ClROS1 gene caused an early flowering phenotype in Arabidopsis thaliana. RNA-seq analysis of the transgenic plants revealed that differentially expressed genes (DEGs) were significantly enriched in the circadian rhythm pathway and that the positive regulator of flowering, CONSTANS (CO), was up-regulated. Additionally, whole-genome bisulphite sequencing (WGBS), PCR following methylation-dependent digestion with the enzyme McrBC, and bisulfite sequencing PCR (BSP) confirmed that the methylation level of the AtCO promoter was reduced, specifically in CG context. Overall, our results demonstrated that ClROS1 accelerates flowering by reducing the methylation level of the AtCO promoter. These findings clarify the epigenetic mechanism by which ClROS1-mediated DNA demethylation regulates flowering.
摘要：
DNA去甲基化参与植物开花的调节，然而，潜在的分子机制在很大程度上仍未被探索。沉默1（ROS1）基因的释放，编码DNA去甲基转移酶，在许多发展过程中起着关键作用。在这项研究中,ROS1基因从菊花中分离，它在树叶中强烈表达，芽和花。ClROS1基因的过表达导致拟南芥的早期开花表型。对转基因植物的RNA-seq分析表明，差异表达的基因（DEG）在昼夜节律途径中显著富集，并且开花的正调节因子，康斯坦斯(CO),被上调了。此外,全基因组亚硫酸氢盐测序（WGBS），用酶McrBC甲基化依赖性消化后的PCR，和亚硫酸氢盐测序PCR（BSP）证实，AtCO启动子的甲基化水平降低，特别是在CG背景下。总的来说,我们的结果表明，ClROS1通过降低AtCO启动子的甲基化水平来加速开花。这些发现阐明了ClROS1介导的DNA去甲基化调节开花的表观遗传机制。
