Global plant diversity patterns: case studies from early branching legume clades

所有最近的研究都表明，物种多样性在时间上、地理区域上和系统发育史上的谱系中分布非常均匀。虽然人们普遍认为，变异性的增加推动了物种的多样化，但梳理多样化的原因仍然是一个挑战。在我的实验室的研究集中在系统学，植物遗传学和重要的经济植物豆科植物（豆科）的进化。有765属，C.豆科植物有19，500种，是第三大开花植物家族，代表了植物进化多样化的最壮观的例子之一，几乎出现在地球仪的每一个生物群落中。我们主要研究该科的热带基底谱系。我的研究的长期目标是使用全面采样，强大和良好解决的遗传学建立稳定的分类，并更好地了解宏观进化形态，生态和地理模式。今后五年将实现三个目标。1)我们将研究多样化的全球模式，以测试五个基础豆类分支之间和内部的显著变化。为了实现这一点，我们将使用一种对100个核基因进行测序的基因组学方法来产生全面采样的基因组。将研究与地理、生物群系、功能性状和花的进化有关的速率变化。2)将研究与植物有关的内在特征，以检验性状依赖的多样化。花的字符将在Detarioideae和Dialioideae，两个谱系，表现出显着的多样性，在花的形态，和功能性状相关的栖息地适应将在Caesalpinioideae，辐射到所有主要的生物群系进行了研究。3)生物地理学和生物群落的演变将在Detarioideae和Dialioideae研究，以确定这些主要是潮湿的森林分支的分布是否可以追溯到早至始新世中期，干燥的环境多样化，建议大多数豆类。使用化石校准的遗传学，我们将调查现今的地理和生态分布，推断祖先生物群系，寻找生物群系变化的证据，并严格评估生物群系保守主义与地质历史在解释这两个分支的分布的相对重要性。我们最近的工作取得了重大进展，朝着一个更强大和稳定的豆科植物遗传学为基础的分类。这里提出的研究提供了范围，以巩固这些努力，以清楚地了解整个地球仪的豆类多样性的模式。这个合作和基础广泛的研究计划为学生提供植物系统学和进化的培训机会，这对于更好地了解全球现有的生物多样性至关重要。

All recent studies suggest that species diversity is distributed very evenly through time, across geographical regions and amongst lineages in phylogenetic history. Although it is widely believed that increased variability drives species diversification, teasing apart the causes of diversification remains a challenge. Research in my laboratory focuses on systematics, phylogenetics and evolution of the economically important plant family Leguminosae (Fabaceae). With 765 genera and c. 19,500 species, legumes are the third largest flowering plant family, represent one of the most spectacular examples of evolutionary diversification in plants, and occur in nearly every biome across the globe. We study the mostly tropical basal lineages of the family. The long term objective of my research is to use comprehensively sampled, robust and well-resolved phylogenies to establish stable classifications and to better understand macro-evolutionary morphological, ecological and biogeographical patterns. Three objectives will be addressed in the next five years. 1) We will examine global patterns of diversification to test for significant rate shifts across and within the five basal legume clades. To achieve this, we will generate comprehensively sampled phylogenies using a phylogenomics approach to sequence 100's of nuclear genes. Rate shifts will be studied in relation to geography, biomes, functional traits and floral evolution. 2) Intrinsic plant-related characteristics will be studied to test for trait-dependent diversification. Floral characters will be examined in Detarioideae and Dialioideae, two lineages that exhibit remarkable diversity in floral morphology, and functional traits related to habitat adaptations will be studied in Caesalpinioideae, where radiations into all major biomes have occurred. 3) Biogeography and biome evolution will be studied in Detarioideae and Dialioideae to determine whether the distribution of these primarily wet forest clades can be traced to an early to mid-Eocene, dry environment diversification, as suggested for most legumes. Using fossil calibrated phylogenies, we will investigate present-day geographic and ecological distributions, infer ancestral biomes, look for evidence of biome shifts and critically evaluate the relative importance of biome conservatism versus geological history in explaining the distribution of these two clades. Our recent work has made significant progress towards a more robust and stable phylogenetically-based classification of legumes. The research proposed here offers scope to consolidate these efforts to clearly understand patterns of legume diversity across the globe. This collaborative and broadly based research program provides opportunities for training of students in plant systematics and evolution, which are essential to a better understanding of existing biodiversity worldwide.