典型半红树植物银叶树种群适应海陆异质性生境的分子基础

银叶树是对海、陆两种异质性生境具有广泛适应能力的典型半红树植物。本项目在前期已测定的银叶树全基因组序列的基础上，在遗传学和表观遗传学（DNA5mC甲基化）两个水平同时开展银叶树自然种群生态适应机制的研究。结合利用种群全基因组重测序与甲基化测序技术，检测并系统比较南中国海周边多地分布在海岸潮间带和内陆两种不同生境的银叶树自然种群遗传变异和表观遗传变异的式样和组成，在多重地理和生境尺度下评估各种进化力量的相对作用；结合采样地微环境的环境因子矩阵数据，揭示生态因子与种群适应性分化间的相关性；探寻不同地点潮间带与内陆生境种群平行进化的证据；解析遗传变异与表观遗传变异对适应性进化的相对贡献。从组学水平全面、系统研究银叶树适应性分化的遗传与表观遗传学机制，为保护、管理和可持续利用这一具有海、陆异质性生境特点的木本植物遗传资源提供理论依据。

Heritiera littoralis is a typical mangrove associate species with extensive adaptability to heterogeneous habitats in both coastal intertidal and inland zones. Based on our previous study of the whole genome sequencing of H. littoralis, we will conduct a research on the ecological adaptation mechanism of natural populations of H. littoralis at the genetic and epigenetic levels (DNA 5mC methylation). The whole genome resequencing combined with bisulfite sequencing of populations will be used to examine and systematically compare the patterns and compositions of the genetic and epigenetic variations of natural populations of H. littoralis distributed in multiple locations of coastal intertidal zones and inland habitats along the South China Sea, respectively. We will explore and assess the role of various evolutionary forces at multiple geographic and habitat scales, and estimate the correlation between ecological factors and population adaptive differentiation by detecting the environmental factors in the microenvironment. We will further explore the evidence of parallel evolution between intertidal zone and inland habitat populations at different sites and reveal the relative contribution of genetic variation and epigenetic variation to adaptive evolution. The comprehensive and systematical study on the genetic and epigenetic mechanism of adaptive differentiation in H. littoralis from Omics levels in this project will provide theoretical insights for the conservation, management and sustainable utilization of this valuable woody plant germplasm resource in heterogeneous marine and terrestrial habitats.