CAREER: Mechanisms of Specificity and Homeostasis in an Obligate Symbiosis: Discovery-based Research at a Regional University

这个项目将研究细菌在稳定所谓的真菌园艺蚂蚁和它们的养殖真菌之间的相互作用中所起的作用。这些蚂蚁是整个美国南部和南北美洲热带地区沙漠和森林生态系统的重要生态成员。了解这些生物可以告诉我们它们是如何影响环境并与环境相互作用的。该项目的详细研究和实验具有重要的社会和科学效益。例如，一些抗真菌共生生物是重要的农业害虫。另一些则是抗生素和抗菌化合物的来源，而另一些则作为生物燃料生产的模型。这项研究将在实验生物学、微生物学和大型分子数据集分析方面培养本科生和研究生，并增加德克萨斯州东部地区大学学生在国内和国际上的曝光率。外联活动包括但不限于(a)在当地博物馆建造活切叶蚁展览，(b)在德州大学泰勒自然保护区建造解释性展览(c)在德州大学泰勒开发强调环境、生物医学和人类健康之间联系的新课程(d)参加并共同组织一年一度的德州大学泰勒达尔文日。共生（生活在附近的不相关生物的生态联系）对地球上所有生命的进化和生态成功至关重要。共生研究面临的核心问题之一是阐明共生如何在动态世界中组织和发挥作用。种植真菌的蚂蚁与特定的真菌形成专性的大型共生关系，这些真菌是蚂蚁为食物而生长的，但也与许多其他细菌和微真菌物种相互作用。蚁群共生是解决功能关系的一个很好的模型，因为蚂蚁和真菌可以通过实验分解和重组成新的组合，从而有可能证明菌落和真菌性能与微生物群落组成之间的联系。本项目特别感兴趣的是与蚂蚁和真菌相关的微生物群落（微生物组）在维持抗真菌群落中所起的作用。拟议的实验将研究与微生物组的相互作用如何促进这种共生关系中不同伙伴的特异性和稳态。这项基于发现的研究将结合密集的实地调查、下一代测序、生物信息学和实验生物学来研究细菌群落在赋予宿主蚂蚁和共生真菌之间稳定性方面的作用。因此，这项研究对理解专性共生的进化和维持具有广泛的意义。

This project will examine the roles that bacteria play in stabilizing the interactions among the so-called fungus-gardening ants and their farmed fungi. These ants are ecologically important members of desert and forest ecosystems throughout the southern US and tropical regions of North and South America. Understanding these organisms informs us how they influence and interact with their environment. Detailed studies and experiments in this project have important societal and scientific benefits. For example, some ant-fungal symbioses are important agricultural pests. Others are sources of antibiotics and antimicrobial compounds, while others serve as models for biofuel production. This research will train undergraduate and graduate students in experimental biology, microbiology and the analysis of large molecular datasets as well as increase the national and international exposure of students at a regional university in east Texas. Outreach activities include but are not limited to (a) construction of a living leaf-cutter ant exhibit at a local museum, (b) construction of interpretative exhibits in the UT Tyler Nature Preserve (c) the development of new courses at UT Tyler that emphasize connections between the environment, biomedicine and human health (d) participating and co-organizing the annual UT Tyler Darwin Day. Symbioses (ecological associations of unrelated organisms living in close proximity) were and are crucial to the evolution and ecological success of all life on earth. One of the central issues facing the study of symbiosis is elucidating how symbioses are organized and function in a dynamic world. Fungus-gardening (attine) ants form an obligate macrosymbiosis with specific fungi that the ants grow for food, but also interact with a number of other bacteria and microfungal species. The attine symbiosis is an excellent model to address functional relationships because the ants and fungi can be experimentally disassembled and reassembled into novel combinations, thus making it possible to demonstrate links among colony and fungal performance and microbial community composition. Of particular interest in this project is the roles that the microbial communities (microbiomes) associated with attine ants and the fungi play in the maintenance of the ant-fungus community. The proposed experiments will examine how interactions with the microbiomes promote specificity and homeostasis with the various partners in this symbiosis. This discovery-based research will combine intensive field surveys, next generation sequencing, bioinformatics and experimental biology to examine the role of the bacterial communities in conferring stability between host ants and symbiotic fungi. As a result, this research has broad implications for understanding the evolution and maintenance of obligate symbioses.