A temperate radiation in a tropical plant family – factors underpinning evolution of the Eurasian Vincetoxicum (Apocynaceae) complex

热带植物科的温带辐射 â 支撑欧亚 Vincetoxum（夹竹桃科）复合体进化的因素

• 批准号: 437386703
• 负责人: Professorin Dr. Sigrid Liede-Schumann
• 金额: --
• 依托单位: Department of Chemistry
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/437386703?language=en
• 关键词: temperate; radiation; tropical; plant; family

Temperate herbaceous clades in mainly tropical, woody Angiosperm families often have undergone accelerated episodes of species diversifications and / or disparification – radiations – in the recent past, frequently associated with the colonization of new habitats. However, little is known about the factors driving such radiations outside some well-studied biogeographic hotspots like, e.g., mountains or islands. In the pollinia-forming, tropical subfamily Asclepiadoideae of Apocynaceae, only three lineages have undergone a substantial radiation in the temperate zones, of which Vincetoxium (s.l.) is the youngest one. Vincetoxicum is a genus comprising several tropical lianescent clades and two herbaceous temperate radiations. One of these, the "Vincetoxicum s.str." clade, has expanded from the Far East via the Asian mountain chains into the Asian steppes and into Europe, from where it has entered the New World with neophytes. To understand the evolutionary history of this recent temperate radiation, we will study three lines of evidence: morphometric, molecular, and chemical. Especially, we test one of the most likely factors contributing to the evolutionary success of this clade, its unusual chemistry featuring phenanthroindolizidine-alkaloids (PIAs). Synthetic analysis will elucidate the phenotypic variation, the genetic basis, and the supposed chemical defence strategy in this clade to test the hypothesis that the most successful lineages are the ones with the best chemical defence system. We will (1) develop a comprehensive morphological dataset allowing the delimitation of "morphospecies"; (2) provide a densely sampled phylogeny of the Vincetoxicum s.str. clade using targeted sequencing of low-copy nuclear genes, allowing the delimitation of coalescent-based species; (3) check the congruence of morphospecies and coalescent-based species and derive a stable species concept for Eurasian Vincetoxicum based on different lines of evidence; a tool urgently needed for future monitoring of Vincetoxicum in the light of climate change and conservation; (4) test the hypothesis that the most successful species are the ones with the best chemical defence system, using quantity and diversity of PIAs as a proxy for the strength of the defence.

在最近的过去，主要是热带木本被子植物科的温带草本枝经常经历物种多样化和/或分化-辐射的加速事件，这通常与新栖息地的殖民化有关。然而，在一些研究充分的生物地理热点（如山脉或岛屿）之外，人们对驱动这种辐射的因素知之甚少。在夹竹桃科的热带花粉形成亚科中，只有三个谱系在温带经历了大量的辐射，其中Vincetoxium （s.l.）是最年轻的一个。长春花属是一个由几个热带线状分支和两个草本温带分支组成的属。其中一种，“Vincetoxicum s.str.”分支，已经从远东通过亚洲山脉扩展到亚洲草原和欧洲，从那里它和新植物一起进入了新世界。为了了解这种近期温带辐射的进化史，我们将研究三种证据：形态计量学、分子和化学。特别是，我们测试了促成这一进化分支成功的最有可能的因素之一，其不寻常的化学特征是phenanthroindolizidine-alkaloids （PIAs）。综合分析将阐明该支系的表型变异、遗传基础和假定的化学防御策略，以检验具有最好化学防御系统的支系是最成功的支系的假设。我们将(1)开发一个全面的形态学数据集，允许“形态物种”的划分；(2)提供vince . toxicum s.str的密集样本系统发育。利用低拷贝核基因的靶向测序进行进化，允许基于聚结的物种的划分；(3)根据不同的证据线，检查形态种和聚结种的一致性，得出欧亚长春花的稳定物种概念；从气候变化和保护的角度出发，迫切需要一种未来监测长春花的工具；(4)利用pia的数量和多样性作为防御强度的代表，检验最成功的物种是具有最佳化学防御系统的物种的假设。