Dimensions US-China: Collaborative Research: Allosomes and dioecy in plants as drivers of multi-level biodiversity

尽管大多数开花植物（被子植物）的花结合了雄性和雌性器官，但据估计，有7%的开花植物是雌雄异株，这意味着雄花和雌花在不同的植物上。所有的杨树和柳树都是雌雄异株，这两个属是美国和中国许多地区最丰富的乔木和灌木。本研究旨在了解杨树和柳树单性花进化的遗传基础，雌雄个体之间防御和挥发性化合物的差异，以及这些植物内部不同的化学特征如何影响昆虫的生物多样性。此外，杨树和柳树也是木材和生物燃料工业的重要组成部分，因此这项研究的结果可能会对如何提高这两个属的生长和产量产生新的见解。中美研究人员的合作将为超过15名研究生和5名博士后提供广泛的跨学科和跨文化培训机会，研究数据将被纳入中美两国机构的课程教材中。数十名来自不同背景的本科生将通过直接参与数据收集和分析，或通过访问数据进行沉浸式研究体验，接受植物基因组学和功能生态学方面的培训。最后，研究人员将领导K-12教师培训讲习班，以德克萨斯州农村代表性不足的群体为目标，鼓励生物多样性基础理论的教学。本研究将通过对杨树和柳属植物性别二态性防御和挥发性化学的全面调查来研究功能生物多样性，并确定性别二态性如何影响传粉者的吸引力、食草动物的取食偏好和整个节肢动物群落结构。生物多样性的遗传方面将通过与常染色体比较的同种异体的种群基因组特征进行研究。研究人员将绘制一组16种柳树和杨树物种的性别决定区（SDR）染色体位置图，确定这些基因组区域是否包含防御和挥发性化学位点，这与它们对SDR运动的理论影响一致，并研究由性拮抗位点与SDR相互作用引起的同种异体分化的预测种群基因组模式。本研究的系统发育部分将通过发展和整合杨树、柳和水杨科密切相关属的强大系统发育，将性别二态性和同种异体进化置于历史背景下，以了解SDR在家族进化过程中移动了多少次，SDR在大小和组成上如何变化，以及SDR的移动是否与种间杂交障碍相关。

Although most flowering plants (angiosperms) have flowers that combine male and female organs, an estimated seven percent of flowering plant species are dioecious, meaning male and female flowers are on separate plants. All poplars and willows are dioecious and these two genera are the most abundant trees and shrubs in many parts of the United States and China. This research aims to understand the genetic basis for the evolution of unisexual flowers in poplars and willows, how defense and volatile chemical compounds differ between male and female individuals, and how different chemical profiles within these plants affects insect biodiversity. Moreover, poplars and willows are also important components of the timber and biofuels industries, so results from this research may lead to new insights into how growth and yield may be improved in the two genera. The collaboration between United States and Chinese researchers will provide extensive cross-disciplinary and cross-cultural training opportunities for over fifteen graduate students and five postdoctoral scholars, and the data generated from the research will be incorporated into teaching materials for courses to be taught in both Chinese and US institutions. Dozens of undergraduates from diverse backgrounds will be trained in plant genomics and functional ecology through direct contributions to data collection and analysis, or through access to the data for research immersion experiences. Finally, researchers will lead K-12 teacher training workshops targeted at under-represented groups in rural Texas to encourage teaching of the foundational theories of biodiversity.This research will address functional biodiversity with a comprehensive survey of gender dimorphism for defense and volatile chemistry in Populus and Salix, and determine how gender dimorphism influences pollinator attraction, herbivore feeding preferences, and overall arthropod community structure. Genetic aspects of biodiversity will be investigated by population genomic characterization of the allosomes in comparison to autosomes. Researchers will map the chromosomal locations of sex determination regions (SDRs) in a suite of sixteen Salix and Populus species, determine whether these genomic regions contain defense and volatile chemistry loci consistent with their theoretical influence on movement of the SDR, and investigate predicted population genomic patterns of allosome divergence caused by interactions between sexually antagonistic loci with the SDR. The phylogenetic component of this research will place gender dimorphism and allosome evolution in a historical context by developing and integrating robust phylogenies of Populus, Salix, and closely related genera within the Salicaceae in order to understand how many times the SDR has moved during evolution of the family, how the SDR has changed in size and composition, and whether movement of the SDR correlates with barriers to interspecific hybridization.