Systematics, biogeography and evolution of northern floras

北方植物区系的系统学、生物地理学和进化

• 批准号: RGPIN-2021-03117
• 负责人: LéveilléBourret, Étienne
• 金额: $ 2.77万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=765219
• 关键词: Systematics; biogeography; evolution; northern; floras

A central aim of systematics is to identify the processes that shape diversity across space and time. Northern floras offer interesting opportunities to do so, as they have been through some of the most intense periods of past climate change. My long term research goal is to discover, classify and protect the awe-inspiring biodiversity of northern plants, and to identify the processes responsible for generating and maintaining this diversity. Towards this goal, I will focus on three short-term objectives that will shed light on the impact of past climate change on evolution of northern floras at three evolutionary scales: macro-evolutionary (Objective 1), micro-evolutionary (Objective 2), and ecological (Objective 3). Objective 1 is to quantify the influence of historical climate change on the diversity and evolution of one of the most abundant plant families in the fossil record, Cyperaceae (>1000 fossils). We will first compile a comprehensive database of all fossils reported in the literature, and re-assess their taxonomic affinities through geometric morphometric analysis (BSc 1). The resulting fossil dataset will be of unprecedented size and quality in angiosperms, enabling high-resolution analysis of plant diversification dynamics, biogeography, niche evolution and fruit evolution throughout the last 100 million years that span the evolutionary history of Cyperaceae (MSc 1). Objective 2 is to develop the first genomic resources for Cyperaceae, and to use them to determine how climate influences the frequency of hybridization and introgression. Two Carex genomes will be assembled to chromosome-scale (PhD 1) at low cost from an experimental hybrid, which will allow estimation of the timing and intensity of ancient introgression events, based on the lengths of introgressed genomic blocks. We will also expand on our previous investigations of host-parasite interactions in Cyperaceae by utilizing Anthracoidea fungi, which preferentially parasitize hybrids, as a proxy to infer the frequency of hybridization in deep time (Msc 2). Objective 3 will be to accelerate taxonomic research on the Freshwater Tidal Flora, a rich but threatened North American centre of endemism. Through parallel taxonomic and population genomic studies of two Cyperaceae (BSc 2, MSc 3) and one Asteraceae (PhD 2) lineage endemic to this Flora, we will discover shared patterns of genetic diversity that can be used to prioritize conservation on the most distinct populations and areas. We will then assemble a complete distribution database of all taxa occurring in the Freshwater Tidal Flora (c. 100 species; BSc 3) to test how area, climatic conditions and distance between estuaries affect endemicity, richness, phylogenetic diversity, and population genetic diversity (PhD 2). This combined approach will allow us to discover large-scale historical and ecological processes that shape diversity at all levels of biological complexity, from genes to species and whole communities.

系统学的一个中心目标是确定塑造跨空间和时间多样性的过程。北方植物区系为此提供了有趣的机会，因为它们经历了过去气候变化最严重的时期。我的长期研究目标是发现、分类和保护北方植物令人惊叹的生物多样性，并确定负责产生和维持这种多样性的过程。为了实现这一目标，我将重点关注三个短期目标，这些目标将在三个进化尺度上阐明过去的气候变化对北方植物区系进化的影响：宏观进化（目标1）、微观进化（目标2）、和生态（目标 3）。 目标 1 是量化历史气候变化对化石记录中最丰富的植物科之一莎草科（> 1000 个化石）的多样性和进化的影响。我们将首先编制文献中报道的所有化石的综合数据库，并通过几何形态分析（BSc 1）重新评估它们的分类学亲和力。由此产生的被子植物化石数据集将具有前所未有的规模和质量，从而能够对跨越莎草科进化史的过去一亿年的植物多样性动态、生物地理学、生态位进化和果实进化进行高分辨率分析（MSc 1）。目标 2 是开发莎草科的第一个基因组资源，并利用它们来确定气候如何影响杂交和基因渗入的频率。两个苔草基因组将以低成本从实验杂交中组装成染色体规模（PhD 1），这将允许根据渗入基因组块的长度估计古代渗入事件的时间和强度。我们还将利用优先寄生杂种的炭疽菌作为推断深时杂交频率的代理，扩展之前对莎草科宿主与寄生虫相互作用的研究（Msc 2）。目标 3 将是加速淡水潮汐植物区系的分类学研究，淡水潮汐植物区系是一个丰富但受到威胁的北美特有中心。通过对该植物区系特有的两种莎草科（BSc 2、MSc 3）和一种菊科（PhD 2）谱系进行并行分类学和群体基因组研究，我们将发现遗传多样性的共同模式，可用于优先保护最独特的群体和地区。然后，我们将建立淡水潮汐植物区系中所有类群的完整分布数据库（约 100 个物种；BSc 3），以测试面积、气候条件和河口之间的距离如何影响地方性、丰富度、系统发育多样性和种群遗传多样性（博士2）。这种综合方法将使我们能够发现大规模的历史和生态过程，这些过程在生物复杂性的各个层面（从基因到物种和整个群落）形成多样性。