物种形成是生物多样性产生的基本机制，也是进化生物学领域最重要的问题之一。作为唯一同时具有海生生境真红树和陆生生境非红树植物的属，老鼠簕属红树植物是研究海岸潮间带植物物种形成与适应性进化的良好系统。我们前期基于少数核基因和叶绿体基因间隔区的分析提示了老鼠簕属现有物种分类地位的不确定性以及属内物种形成事件的复杂性，但确切的种间界限和物种形成模式还需从群体组学层次进一步探讨。在前期研究基础上，本研究将采用前沿的居群基因组和比较转录组学方法，利用基于贝叶斯原理的算法对相关物种在基因组水平上进行界定；在概率模型下对物种形成的模式进行统计检验，并阐明马来半岛作为历史地理障碍在该属红树物种形成中的角色；同时通过与陆生近缘种转录组的比较，从自然选择和功能基因的角度探讨老鼠簕属红树植物在潮间带极端环境适应性进化的分子机理；为理解印度-西太平洋地区红树植物物种形成机制及合理保护和利用红树植物资源提供理论参考。

Speciation is one of the most fundamental and important problems in evolutionary biology. As a unique genus consisting of both true mangrove and terrestrial species, Acanthus represents an ideal system for studying the origin and adaptive evolution of mangrove plants. Our previous studies using individual nuclear genes and chloroplast fragments have revealed potential cryptic speciation and taxonomic status uncertainty within Acanthus mangroves, hinting the necessity of reclassification and intense research on speciation and diversification of these species. In this study, we shall further investigate the delimitation and speciation of Acanthus mangroves on a genome-wide scale using advanced population genomic and comparative transcriptomic methods. Based on genome-wide SNP data collected from reduced-representation genome sequencing, we shall delimit the numbers and boundaries of species within Acanthus mangroves using several different species discovery (parametric and non-parametric) and species validation (coalescent-based) approaches. Based on the species delimitation results and estimation of population demographic parameters using multilocus data collected from next-generation sequencing, we shall conduct statistical testing and computational simulation of various speciation models to determine the most appropriate scenario of speciation, and also perform hypothesis-testing to illustrate the historical role that Malaysian peninsula has played as a land barrier in the speciation of Acanthus mangroves. Meanwhile, we shall identify mangrove-specific genomic components and candidate positively selected genes across Acanthus mangroves through transcriptome comparison with their terrestrial congeners, to understand the molecular mechanism of mangroves’ speciation and adaptive evolution under extreme intertidal conditions from a perspective of nature selection and functional genomics. This study will provide insights on mangroves’ speciation and diversification in the Indo-West Pacific region and also offer reference for the protection and rational use of mangrove resources.