Collaborative Research: Resolving the relationships of Melastomataceae, one of the world's most diverse flowering plant radiations

褐花科是地球上第八大开花植物科，有5600多种，其中大部分生长在新世界的热带地区。目前尚不清楚为什么这个家族如此多样化，但它的一些有趣的结构变异可能起了作用。这个科表现出几个不寻常的特征，包括容纳蚂蚁或螨虫的特殊结构，改良的花部分，以及果实类型的广泛变化。植物的生长形式也各不相同，从一年生植物到灌木到乔木，甚至附生植物或藤蔓植物。该项目旨在通过使用基因组数据建立该家族约3000个物种的进化树，探索是否有任何这些因素可能对Melastomataceae的极端多样性做出了贡献。然后，研究人员将测试该家族在大陆和环境中的地理起源和随后的运动，形态和遗传特征的演变，以及在全球范围内分布的相关多样化速率变化。这个合作项目代表了一个解决物种和广泛的热带植物辐射的模型，并将阐明地球上最大的热带植物家族之一的起源和随后的多样化。两名博士后学者和一名研究生将接受培训，研究人员将为各种学生提供短期培训课程。该项目的发现将在佛罗里达自然历史博物馆和纽约植物园展出，这两个博物馆每年的参观人数超过50万。由于缺乏足够的主要辐射系统发育数据，了解全球热带被子植物多样性的产生往往变得复杂。鉴于其广泛的地理分布、形态多样性和规模，Melastomataceae是开发综合系统基因组数据集来测试主要热带辐射的地理起源、形态进化和多样化率的理想模型，这是目前基于有限的全球数据集难以完成的任务。采用Hyb-seq方法，该项目将产生系统基因组数据集，使用384个核位点和整个质体来重建至少3000个物种在所有主要谱系中的系统发育。该项目的五个主要目标是：1)对所有主要群体之间的关系产生一个健全的系统发育假说；2)估计关键进化事件的时间和整个家族的多样化率，包括与形态进化的相关性；3)分析生物地理情景，确定家族起源，以及多样化率与主要生物地理变化的相关性；4)利用来自我们的核位点的等位基因频率来估计整个家族的多倍体程度，以推断整个树的染色体进化；5)根据我们的系统发育假设，结合描述主要谱系的形态学特征，建立健全的分类。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Melastomataceae are the eighth largest family of flowering plants on the planet with more than 5600 species, most of which grow in the New World tropics. It is not known why this family is so diverse, but some of its interesting structural variants may have played a role. The family exhibits several unusual traits, including special structures that house ants or mites, modified floral parts, and wide variation in fruit type. The plants’ growth form also varies, ranging from annuals to shrubs to trees, and even epiphytes or vines. This project aims to explore whether any of these factors may have contributed to the extreme diversity of Melastomataceae by using genomic data to build an evolutionary tree for approximately 3000 species from the family. The researchers will then test the geographic origin and subsequent movement of the family across continents and environments, the evolution of morphological and genetic features, and associated diversification rate shifts throughout the worldwide distribution of Melastomataceae. This collaborative project represents a model for tackling speciose and widespread tropical plant radiations and will shed light on the origin and subsequent diversification of one of the largest tropical plant families on the planet. Two postdoctoral scholars and a graduate student will be trained, and the researchers will offer short training courses to a variety of students. The project’s discoveries will be highlighted in exhibits at the Florida Museum of Natural History and the New York Botanical Garden, which have a combined annual visitation of over 500,000 people.Understanding the generation of tropical angiosperm diversity worldwide is often complicated by the lack of sufficient phylogenetic data for major radiations. Given its broad geographic distribution, its morphological diversity, and its size, the Melastomataceae is an ideal model for developing a comprehensive phylogenomic dataset to test geographic origins, morphological evolution, and diversification rates of a major tropical radiation, a task currently intractable based on limited global datasets. Taking a Hyb-seq approach, the project will produce phylogenomic datasets using 384 nuclear loci and entire plastomes to reconstruct the phylogeny of at least 3000 species across all major lineages of the Melastomataceae. The five principal goals of the project are to: 1) generate a robust phylogenetic hypothesis of relationships among all major groups; 2) estimate the timing of key evolutionary events and diversification rates across the family, including correlations with morphological evolution; 3) analyze biogeographic scenarios and determine the origin of the family, as well as correlations between diversification rates and major biogeographical shifts; 4) estimate the degree of polyploidy across the family using allele frequencies from our nuclear loci to infer chromosomal evolution across the tree; and 5) develop robust classifications based on our phylogenetic hypotheses, incorporating morphological characters delineating major lineages.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.