CAREER: Coevolutionary Community Dynamics of Symbiotic Nitrogen Fixing Associations

我们世界上的一切都被称为微生物组的复杂微生物群落所覆盖。这些微生物群对人类健康、清洁环境和高产作物都很重要。由于它们比宿主小得多，微生物可以进化得更快。在微生物组中，一些理论模型预测更快的进化将导致导致更严重的疾病，而其他模型预测更快的进化将导致有益的微生物变得更加有益。了解这些结果中的每一个发生的时间对于提出管理微生物组的策略非常重要。本计画将利用共同进化理论模型来了解定植在三叶草根部的微生物群落如何互动与进化。三叶草是许多农作物的亲戚，如豆类、苜蓿和鹰嘴豆，这些信息可以用来提高农业产量和土壤健康。学生将接受研究这些微生物的方法培训，并将分离菌株，分析基因组和生理学，并测量生态相互作用。该项目将在太平洋西北部招募服务不足的美洲土著学生。该项目还将制作一个共同进化的视频游戏，将联合收割机推广和教育与研究相结合。一个研讨会汇集了学生研究人员，植物学家和理论家将催化在这个快速发展的领域的变革性研究。宿主相关的微生物群落是宿主性状和生态系统过程的关键介质，一个科学前沿是了解这些社区如何在自然界中相互作用和共同进化。三叶草根瘤微生物群落是研究这些过程的理想模式系统。该项目有三个关键要素：（1）在博德加湾建立一个可访问的现场系统，可以收集宿主和相关微生物的长期数据，（2）能够将关键参与者带入实验室，以测量宿主-微生物和微生物-微生物相互作用的分子基础，评估适应性协方差的模式，并进行实验性共同进化，以及（3）可以用经验数据参数化以预测群落组装和共同进化动态的数学模型。该项目将解决（1）进化速率的不对称性如何影响复杂社区的共同进化，（2）“红皇后”动态-敌对者之间的军备竞赛-超过“红国王”动态的场景，快速进化的互利主义者进化出昂贵的特征，增强宿主适应度，以及（3）多方相互作用如何影响宿主利益和专业化。通过将不同进化时间尺度的经验测量与数学模型联系起来，该项目将有可能深入了解复杂的共同进化宿主相关社区的一般特性。该奖项反映了NSF的法定使命，并被认为值得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来支持。

Everything in our world is covered in complex communities of microorganisms called microbiomes. These microbiomes are important for human health, clean environments, and productive crops. Since they are much smaller than their hosts, microorganisms can evolve much faster. Within the microbiomes, some theoretical models predict that faster evolution will result in microorganisms that cause more severe disease, whereas other models predict that faster evolution will cause beneficial microorganisms to become even more beneficial. Understanding when each of these outcomes occurs will be important for coming up with strategies to manage microbiomes. This project will use coevolutionary theoretical models to understand how communities of microorganisms that colonize the roots of clover plants interact and evolve. Clover is a relative of many crop plants such as beans, alfalfa, and chickpeas, and this information can be used to improve agricultural yield and soil health. Students will be trained in methods to study these microorganisms and will isolate strains, analyze genomes and physiology, and measure ecological interactions. The project will recruit underserved Native American students in the Pacific Northwest. This project will also produce a coevolutionary video game that will combine outreach and education with research. A symposium bringing together student researchers, empiricists, and theoreticians will catalyze transformative research in this rapidly moving field.Host-associated microbial communities are key mediators of host traits and ecosystem processes, and a scientific frontier is understanding how these communities interact and coevolve in nature. Clover nodule-associated microorganismal communities are an ideal model system to study these processes. This project has three key elements: (1) an accessible field system at Bodega Bay, amenable to the collection of long-term data on both hosts and associated microorganisms, (2) the ability to bring key players into the lab to measure the molecular basis of host-microorganism and microorganism-microorganism interactions, assess patterns of fitness covariance, and conduct experimental coevolution, and (3) mathematical models that can be parameterized with empirical data to predict community assembly and coevolutionary dynamics. The project will address (1) how asymmetries in evolutionary rates influence coevolution in complex communities, (2) scenarios in which 'Red Queen' dynamics–arms races between antagonists–outpace 'Red King' dynamics, where rapidly-evolving mutualists evolve costly traits that enhance host fitness, and (3) how multi-partite interactions influence host benefit and specialization. By linking empirical measurements over varying evolutionary timescales to mathematical models, this project will potentially generate insight into general properties of complex coevolving host-associated communities.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.