Collaborative Research: Host specificity strategies in a binary mutualism: physiological and molecular processes and evolutionary relationships

包括人类在内的所有动植物都进化成与微生物共生。在细胞水平上，复杂的分子电路监测微生物种群，并对防御有害微生物或招募和维持有益微生物做出反应。关于动物如何区分不同的微生物，使它们能够有选择地招募或限制微生物定居，目前的科学知识有限。本研究的重点是了解细菌共生体如何与动物宿主相互作用和影响，以及这些相互作用如何影响物种间合作的进化。三名具有互补专业知识的研究人员将对小型土壤蛔虫(线虫)进行合作研究，这些蛔虫已经进化出与特定细菌群体的互惠关系。线虫和细菌一起形成杀虫复合体，对广泛的昆虫宿主有效，它们从这些宿主中获得繁殖和传播所需的营养。这些关联涉及不同种类的线虫和细菌，目前的研究表明，不同的组合进化出了不同程度的相互依赖。对这些合作关系的研究有望深入了解影响微生物共生的选择性和功能的过程。为了帮助实现这一潜力，这个多学科研究小组将首次调查有助于该系统中宿主适应性的特定细菌特征。这些知识对于我们理解影响互惠伙伴之间专业联系与一般联系演变的选择压力至关重要。这三个合作机构的高中生、本科生、研究生和博士后将通过直接的科学研究，在进化、分子生物学、线虫学、昆虫学和细菌学领域进行培训。因此，该项目将提供对动物识别、维持和受益于其有益微生物伙伴的无处不在的过程的基本见解，并将有助于培训具有进一步应用这些知识的专业知识的未来科学家。

All plants and animals, including humans have evolved to live in symbiotic association with microbes. At the cellular level, complex molecular circuitries monitor microbial populations and respond to either defend against harmful microbes, or recruit and maintain beneficial microbes. Current scientific knowledge is limited with regard to how animals distinguish among different microbes, enabling them to selectively recruit or restrict microbial colonization. This research focuses on understanding how bacterial symbionts interact with and affect their animal hosts, and how these interactions influence the evolution of inter-species cooperation. Three investigators with complementary expertise will conduct collaborative research on small soil-dwelling roundworms (nematodes) that have evolved mutually beneficial associations with a specific group of bacteria. Together the nematodes and bacteria form insecticidal complexes effective against a wide range of insect hosts, from which they derive nutrients for reproduction and dissemination. These associations involve different species of nematodes and bacteria, and current research indicates that different combinations have evolved varying degrees of dependence on each other. Research on these cooperative associations is poised to yield insights into the processes influencing selectivity and function of microbial symbioses. To help achieve this potential, this multidisciplinary research team will investigate for the first time specific bacterial traits contributing to host fitness in this system. Such knowledge will be critical to our understanding of the selective pressures influencing the evolution of specialized versus generalized associations between mutually benefiting partners. High school, undergraduate, graduate, and post-doctoral students at the three collaborating institutions will be trained in the areas of evolution, molecular biology, nematology, entomology, and bacteriology through direct scientific inquiry. Thus, this project will provide fundamental insights into the ubiquitous process by which animals recognize, maintain, and benefit from their beneficial microbial partners, and will help train future scientists with the expertise to further apply this knowledge.