豆科植物属水平的生命之树及其时空演化

Species diversity of different lineages inhabiting the Earth is strikingly heterogeneous. The evolutionary success is responsible for those speciose lineages, but discerning what forces have driven the evolutionary success is a major challenge in evolutionary biology. The legume family (Leguminosae) is the third largest plant family and one of the most evolutionarily successful lineages of flowering plants. However, the patterns of diversification across the whole family and its associations with geography, ecology and other traits are unclear. In this proposal, we will first reconstruct a most comprehensive phylogenetic framework to date at generic level for the family using five chloroplast (rbcL, matK, psbA-trnH and trnL-F) and nuclear (ITS) loci on the basis of our previous studies and data in GenBank. The combined data set of five loci will be assembled using a supermatrix method, which contains approximately 700 genera, 1500 species in the family. Analyses of temporal and spatial diversification for this sparsely sampled phylogeny of legumes as a whole will be done, in order to gain preliminary insights into the extent of among-lineage variation in diversification rates across the family. Based on the early stage of these analyses, initial ideas about the dynamics of legume diversification as well as the potential environmental factors and key innovations within the family to shed light on the evolutionary success of legumes will be highlighted.

在生命进化过程中多样化的式样和相关制约因素是进化生物学领域最基本的命题之一。豆科是被子植物中物种多样性最高的类群之一，也是进化最成功的代表，但豆科植物在时间和空间上的多样化式样如何，受哪些关键创新和外部环境因素影响并不清楚。本项目拟在已有研究的基础上，选取豆科植物约700属（约占整个科属的95%）1500种，利用5个DNA片段组装超级分子矩阵，重建豆科植物属级水平的生命之树。然后整合系统发育、分化时间、祖先分布区、多样化和关键性状进化等分析方法，阐明豆科植物在地史时期的多样化式样，探讨科内不同支系的关键性状和环境因素的联系，从而揭示其多样性动态变化的规律和机理。通过本项目研究，不仅有助于深入理解豆科植物的多样化历史，而且为今后开展其他植物大类群的生物多样性进化的研究提供参考。