水稻5-羟甲基胞嘧啶表观遗传调控的研究

5-hydroxymethylcytosine，5-hmC，as a novel epigenetic markers，has made a series of important advances in animal system including its biosynthesis, function, tumor clinical application and detection technology. However, there is no any reports of 5-hmC in the plant system. In order to answer if there exist 5-hmC in plant system, We will adapt the 5hmC specific chemical labeling and affinity methods and second-generation sequencing technology, systematically detect the amount of 5-hmC modification in about ten major developmental stages of tissue samples in indica rice 93-11, and draw a whole genome picture of 5-hmC modification. Importantly, through constructing the whole genome-wide 5-mC and 5-hmC maps in inflorescence development 1-4mm periods in indica rice, and in the super-hybrid rice combination, we will study the dynamic equilibrium mechanism of DNA methylation, and the regulatory mechanism of 5-hmC in inflorescence development and heterosis. Combination of biochemical and genetic experiments to study the biosynthesis of the plant 5-hmC. A comprehensive understanding of the DNA epigenetic modification of the regulation of plant development has important biological significance, to fill the plant 5 -hmC DNA research gap and provide new tools and new ideas to reveal the molecular mechanism of higher plant development.

5-羟甲基胞嘧啶作为一种新颖的表观遗传标记, 在动物系统中就其生物合成、功能、肿瘤临床应用研究和检测技术等已经取得了一系列重要的进展。然而在植物系统中尚未有任何5-hmC的报道。本项目将结合5hmC 特异的化学修饰富集方法和二代测序技术，通过检测籼稻9311主要发育时期组织样本的5-hmC修饰丰度、富集修饰区序列并测序，构建全基因组的5-hmC修饰图谱。并通过系统构建籼稻9311花序早期发育四个不同时期和同一时期超级杂交稻组合的5-mC和5-hmC的全基因组图谱，研究DNA甲基化的动态平衡机理，及5-hmC在花序发育与杂种优势中的功能和调控机制。进而结合生化与遗传学实验，研究植物5-hmC的生物合成过程，对全面了解DNA表观修饰调控植物发育具有重要的生物学意义，也填补了目前植物5-羟甲基DNA表观研究的空白，更为揭示高等植物生长发育的分子机理提供了新手段和新思路。

本项目采用免疫组化方法和LC-MS/MS/MS质谱技术进行了水稻不同组织5-hmC表观修饰的定性和定量检测，发现水稻中存在较低含量的5-hmC表观修饰；结合5hmC 特异的化学修饰富集方法和二代测序技术，构建了超级杂交水稻LYP9及其亲本93-11和PA64s全基因组的5-hmC修饰图谱，揭示了5-hmC表观修饰的富集分布于异染色质区的分布特征；通过全基因组甲基化修饰的高覆盖度测序和转录组测序，分析比较了5-mC和5-hmC的动态变化规律，探索了DNA甲基化的动态平衡机理；结合基因表达数据，揭示了5-hmC表观修饰抑制转座基因活性的分子调控机制。本研究填补了目前植物5-羟甲基DNA表观研究的空白，对全面了解DNA表观修饰及其生物学意义具有重要的意义，也更为揭示高等植物生长发育的分子机理提供了新手段和新思路。