小RNA表观遗传调控转座子的进化模式是进化生物学和表观遗传学共同关心的热点问题，对理解植物维持基因组稳定性的进化机制有重要意义。本项目拟以占据海岸潮间带极端生境的红树植物为研究材料，在前期工作基础上，通过表观基因组和转录组测序，研究转座子年龄、小RNA丰度、甲基化程度及其与基因距离和表达量的相互关系，揭示红树植物中小RNA介导转录沉默和转录后沉默表观调控转座子的进化动态及其影响基因表达进化的一般规律；进一步，结合群体基因组数据及理论建模，阐明表观调控和进化力量共同抑制红树植物转座子扩增的进化轨迹；最终，与模式植物中小RNA表观调控转座子的进化模式比较，理解极端环境下红树植物维持基因组稳定性的进化机制。所得结果将有助于解析植物基因组多样性的来源，为揭示表观遗传调控在极端环境下植物基因组及基因表达进化中所起的作用提供崭新的认识。

Evolution of the small RNA-mediated epigenetic control of transposable elements, which is pertinent to the maintenance of genome stability, is a hot issue in the fields of evolutionary biology and epigenetics. Mangroves are a group of woody plants that thrive under extreme environments in tropic and sub-tropic intertidal zones. Using integrated omic analyses, we shall study the small RNA-mediated epigenetic control of TEs and its impact on whole genome gene expression, evaluate the relative contribution of transcriptional gene silencing (TGS) and post-transcriptional gene silencing (PTGS) to inhibit individual TE families, infer the evolutionary dynamics of genetic conflicts between TEs and small RNAs based on population genetics modelling, and compare the patterns of genome and gene expression evolution of mangroves with those of territorial model plants. The results of this study may reveal the genomic mechanisms underlying mangrove genome stability in facing the extreme environments of intertidal zones and provide a fresh understanding of the genomic basis underlying plant adaptive evolution in extreme environments.