Genomic exploration of adaption and speciation in plant-insect interactions

植物-昆虫相互作用中适应和物种形成的基因组探索

• 批准号: RGPIN-2022-04819
• 负责人: Weis, Arthur
• 金额: $ 2.4万
• 依托单位: University of Toronto
• 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=751460
• 关键词: Genomic; exploration; adaption; speciation; plant

The development and maintenance of population differentiation in the face of gene flow is one of the long-standing issues in evolutionary biology. A recent neutral model from my group (CCV# 5) shows that naturally assorting traits, like flowering phenology, synergize Isolation-by-Distance to amplify population genetic structure, even on a continuous landscape. This interesting result is the departure point for much of the work planned over the next 5 years. We will integrate theoretical and genomic approaches to delineate phenology's role in the origin and maintenance population differentiation. Individual-based and analytical models will probe the contribution of phenological assortative mating to the emergence of population genetic structure. Empirical work focuses on the interaction between goldenrod (Solidago spp.) and the gall-inducing insect, Eurosta solidaginis. We will take a genomic approach to examine two distinct hostplant shifts that reflect early stages of ecological speciation. Work is organized around three basic themes. Theme 1. Modeling the Impact of Phenological Assortative Mating on Population Differentiation: This builds on our basic neutral model showing that Isolation-by-Distance is strongly amplified when assortative for mating period induces Isolation-by-Phenology. We will focus on spatial heterogeneity in selection on mating phenology itself, and on the development of linkage disequilibrium between phenology QTL and loci for other traits under local selection. This general approach can inform our understanding the interaction of spatial arrangement with phenological variation to shape population genetic structure, with applications to evolution along clines and ecological speciation. Theme 2. Phenology in Speciation of Phytophagous Insects: Ecological speciation can occur when divergent section on prezygotic isolating traits counter homogenizing gene flow. This divergent selection should produce should "genomic islands" of differentiation-linkage groups cantered on loci promoting reproductive isolation. Studies finding genomic islands have not always determined if they center on adaptive/barrier loci under divergent selection. We will examine two distinct host-shifts by Eurosta, one occurring in sympatry and one in parapatry, to determine genomic islands differ in length, and if they center on loci affecting insect emergence phenology and/or host recognition. Theme 3. Gall Size and Genomic Evidence for Stabilizing Selection: The counter-balancing selection by parasitoids and birds on the goldenrod stem gallmaker is literally a textbook example of stabilizing selection. Quantitative genetic studies indicate the gall-size variation is in part attributable to insect genetic variation, which may in part be due to the timing of attack. Genotype-by-sequencing will locate QTL for gall size and determine if allele frequencies shift in one direction with parasitoid attack, then reverse with bird attack.

面对基因流动，种群分化的发展和维持是进化生物学长期存在的问题之一。我的小组最近的一个中性模型（CCV# 5）表明，自然的繁殖特征，如开花物候，协同隔离距离扩大种群遗传结构，即使在连续的景观。这个有趣的结果是未来5年计划的大部分工作的出发点。我们将整合理论和基因组的方法来描绘物候的起源和维持种群分化的作用。个体为基础的分析模型将探讨物候期交配的人口遗传结构的出现的贡献。实证工作的重点是一枝黄花（一枝黄花属）之间的相互作用。还有一种能引起胆汁分泌的昆虫，实心弯角藻。我们将采取基因组的方法来研究两个不同的寄主植物的变化，反映了生态物种形成的早期阶段。工作围绕三个基本主题展开。主题1.模拟物候交配对种群分化的影响：这是建立在我们的基本中性模型的基础上的，该模型表明，当交配期的不确定性诱导物候隔离时，距离隔离被强烈放大。我们将集中在交配物候本身的选择空间异质性，并在当地选择的物候QTL和其他性状的基因座之间的连锁不平衡的发展。这种一般的方法可以告知我们理解的相互作用的空间安排与物候变化，以塑造人口的遗传结构，与应用进化沿着倾斜和生态物种形成。主题2.植食性昆虫物种形成中的物候学：当合子前分离性状的分歧部分与基因流相反时，生态物种形成就可能发生。这种不同的选择应该产生“基因组岛”的分化连锁集团集中在促进生殖隔离的基因座。发现基因组岛的研究并不总是确定它们是否集中在趋异选择下的适应性/障碍基因座上。我们将研究两个不同的主机转移的Eurosta，一个发生在同域性和parapatry，以确定基因组岛的长度不同，如果他们中心的基因座影响昆虫出现物候和/或主机识别。主题3.瘿大小和稳定选择的基因组证据：拟寄生蜂和鸟类对一枝黄花茎瘿的平衡选择实际上是稳定选择的教科书例子。定量遗传学研究表明，胆囊大小的变化部分归因于昆虫遗传变异，这可能部分是由于攻击的时间。基因型测序将定位虫瘿大小的QTL，并确定等位基因频率是否随着寄生虫攻击而向一个方向移动，然后随着鸟类攻击而逆转。