橐吾属-垂头菊属-蟹甲草属复合体（菊科-千里光族）属级水平的系统发育研究

The Ligularia-Cremanthodium-Parasenecio complex (LCP complex), with the center of diversity in China, is one of the two major assemblages of genera within subtribe Tussilagininae (Asteraceae-Senecioneae). The generic circumscriptions and relationships in the complex have long been controversial. Recent molecular phylogenetic studies, although supporting the monophyly of the complex, have further shown that the five genera currently defined (viz., Ligularia, Cremanthodium, Parasenecio, Sinosenecio, and Tephroseris) are not monophyletic and their generic boundaries and relationships with satellite genera urgently need revisions. In our previous studies, the macro- and micro-morphological, palynological, and cytological characters of the complex were extensively studied, and molecular phylogenetic study focusing on the genus Parasenecio was conducted using five chloroplast and two nuclear ribosomal DNA markers. The results clearly revealed the polyphyly of Parasenecio and the unresolved relationships with its three satellite genera (Miricacalia, Sinacalia, and Syneilesis). Owing to insufficient taxon samplings and relatively low phylogenetic resolution, however, the phylogenetic relationships of other genera of the complex (especially Ligularia, Cremanthodium, Sinosenecio, Tephroseris, and Farfugium) are still largely unresolved. In this project, we will increase the taxon sampling from the whole LCP complex and add six cpDNA and four single- or low-copy nuclear DNA markers to perform a thorough phylogenetic analysis of the complex in order to generate a robust overall generic-level phylogenetic framework for the complex. Combining the phylogeny and various evidence from macro- and micro-morphology, palynology, and cytology, we aim to revise the generic boundaries and the relationships among different genera. Moreover, on the basis of the phylogenetic framework we will analyze the evolutionary patterns of some important characters and study the biogeography of the complex. This project would shed new light on the phylogenies of subtribe Tussilagininae and tribe Senecioneae, and also increase our understanding on the diversification of the Eastern Asian flora.

橐吾属-垂头菊属-蟹甲草属（LCP）复合体属于菊科千里光族款冬亚族，集中分布于我国。该复合体内部的属间界限和属间关系长期存在争议。近年来的分子系统学研究进一步明确指出，LCP复合体虽然是单系，但其内部传统定义的几个大属均非单系，其属间界限以及与卫星属的关系都需要重新定义。我们前期对LCP复合体开展了全面的形态学、解剖学、孢粉学和细胞学性状研究，并以蟹甲草属为研究重点，利用5个叶绿体和2个核糖体DNA片段开展了分子系统学研究。研究结果阐明了蟹甲草属的复系性质及其与卫星属（小蟹甲属、华蟹甲属和兔儿伞属）的亲缘关系，但由于取样和分辨率不足，还未能彻底解决其他属的系统发育关系。本项目拟在前期研究的基础上，针对这些属进行密集取样，补充6个叶绿体和4个核DNA片段，构建LCP复合体完整的系统发育框架，结合其他学科证据，厘清其内部的属间界限和属间关系，并分析关键性状的进化式样，和复合体的起源和分化历史。

橐吾属-垂头菊属-蟹甲草属（LCP）复合体属于菊科千里光族款冬亚族，集中分布于我国。该复合体内部的属间界限和属间关系长期存在争议。近年来的分子系统学研究进一步明确指出，LCP复合体虽然是单系，但其内部传统定义的几个大属均非单系，其属间界限以及与卫星属的关系都需要重新定义。在密集取样的基础上，本研究通过目的片段杂交富集和二代测序技术，重建了LCP复合体的系统发育关系。结合形态学、解剖学和细胞学证据，我们重新定了复合体内部的属间界限和属间关系，并描述了3个新属。同时，我们进一步对LCP所属的款冬亚族的异源多倍化问题进行了研究。该亚族物种丰富、染色体基数很高（主要为x = 30和40）。前人的研究表明该亚族可能为异源多倍化起源，但未能给出明确的分化式样。本研究通过详尽的分析（包括开发了新程序HomeoSorter）解决了这一问题。款冬亚族主要涉及3次杂交多倍化事件，其中，前两次事件涉及Brachyglottis群、千里光亚族和Chersodoma， 形成了狭义款冬亚族。第三次事件涉及狭义款冬亚族中Arnoglossum群与Chersodoma，形成了Gynoxys群。这一结果得到了染色体证据最有利的支持。此外，我们还解决了千里光族多个长期遗留的分类学和命名学问题。本研究的开展对我们认识千里光族和东亚植物区系的进化式样有重要意义。