蔷薇分支初生四倍体及其近缘二倍体比较DNA甲基化组学研究

Polyploidizations, or whole genome duplications (WGDs), have long been recognized as a major force in angiosperm evolution. Plant genomes must remodel to adapt to the strong genome shocks caused by WGDs. As a result, epigenetic variation takes place and it plays an important role in the adaptation and evolution of genomes. Natural nascent polyploids are ideal materials to study short-term changes of genomes induced by WGDs. This study focuses on DNA methylation which is one of the most important heritable and well-studied epigenetic modifications, and proposes to generate and compare genome-wide methylomes, transcriptomes and siRNAomes of five species. In the research, Brassica napus and Medicago sativa represent nascent allopolyploid and autopolyploid from eudicots rosids clade; Brasscia rapa and Brassica oleracea take the place of relative diploids of Brassica napus; Medicago truncatula stand for relative diploid of Medicago sativa. Subsequent comparative analyses will lead to a better understanding of relationship between epigenetic variation and short-term changes of genomes induced by recent polyploidization event from Rosids Asterids. The proposed study thus is of greatly significance in laying theoretic foundation for the research of plant genome evolution after WGDs.

多倍化又称全基因组重复，在植物进化中起到关键作用。多倍化事件会给植物基因组造成强烈的冲击，基因组重塑是对多倍化冲击的应答，而表观遗传变异是基因组应答的重要内容。自然初生多倍体是研究基因组响应多倍化冲击造成短期效应的理想材料。本项目针对表观遗传修饰中的核心内容DNA甲基化，以十字花科甘蓝型油菜和豆科紫花苜蓿代表真双子叶植物蔷薇分支同源和异源初生多倍体，构建甘蓝型油菜及其近缘二倍体白菜、甘蓝，紫花苜蓿及其近缘二倍体蒺藜苜蓿的全基因组DNA甲基化图谱、转录组图谱、小RNA图谱。基于比较DNA甲基化组学方法，开展对真双子叶植物蔷薇分支近期多倍化事件发生后表观遗传变异与基因组短期效应关系的研究。以期为多倍化事件发生后植物基因组进化研究提供理论基础。