龙脑香科青梅属不同果实类型传播与适应的生态遗传学研究

龙脑香科是东南亚热带雨林的建群种和优势种，普遍具有萼片特化发育形成的翅果，可能是谱系分化和长距离扩散的关键创新。青梅属果实类型多样，既有2枚萼片显著伸长能够飞行的翅果，也有萼片正常发育果实无翅的类型。不同果实类型的传播能力是否有差别？果实构造变化是否为了适应传播媒介转变？果实传播如何影响种群遗传动态？为探究上述问题，我们选取青梅属果实构造截然不同的两物种，小果有翅的青梅和大果无翅的V. rassak，通过测量果实传播距离和分析小尺度空间遗传结构，研究不同果实类型的扩散能力；采用全基因组重测序获得核与叶绿体两个基因组的单核苷酸多态性，推断种群遗传结构、历史动态与基因流，分析叶绿体的谱系历史，评估种子散布对物种迁移、遗传变异、种群分化和基因流的贡献。对比分析不同果实类型，揭示果实构造和传播对种群遗传的影响。本项目将为理解翅果这一龙脑香科关键创新的进化显著性，以及果实的传播适应提供深入见解。

Species of Dipterocarpaceae constitute the key and dominant elements in Southeast Asian rainforests. The fruits of most dipterocarps are samara with two to five wings being derived from sepals, which is likely to be a key innovation for lineage diversification and long-distance dispersal. Species of Vatica in Dipterocarpaceae have diverse fruit architectures, including samara with two long wings and wingless fruits whose five sepals develop normally without wind dispersal capability. Do the divergent fruit architectures result in different dispersal potential? Is the alteration of fruit architecture related to shifting of dispersal carriers? How different modes of fruit dispersal impact the dynamics of population genetic process? In order to answer the above interesting questions, we selected two species in Vatica with contrasting fruit architectures, one is Vatica mangachapoi with small fruit and two long wings, and the other is V. rassak with large but wingless fruit. We plan to measure fruit dispersal distance, and analyze fine-scale spatial genetic structure to explore the dispersal potential of typical Vatica fruits. Whole genome resequencing will be performed to obtain SNPs from both nuclear and chloroplast genomes, and then population structure, historical demography and gene flow of the two studied species can be inferred. Moreover, the evolutionary history of maternally inherited chloroplast genome could be reconstructed. Based on these analyses, we can evaluate the contribution of seed dispersal to species migration, genetic variation, population divergence and gene flow. Furthermore, through comparative analyses of species with divergent fruit types, we hope to illuminate the impact of fruit architecture and dispersal on population genetic processes. This project should provide deep insights into not only the evolutionary significance of samara as the "key innovation" in Dipterocarpaceae, but also the adaptation of fruit for dispersal purpose.