BEE: Unraveling the ecological and evolutionary factors shaping host-associated microbial communities

生态学和进化论中的一个主要问题是：是什么因素塑造了微生物群落？了解形成微生物群落的因素很重要，因为微生物在生态系统功能以及人和动物健康中发挥着关键作用。尽管有许多研究，但我们对是什么驱动微生物群落的组装、组成和动态仍然缺乏了解。我们在知识上的差距在很大程度上是由于生态学和进化论领域之间缺乏整合。由于微生物进化如此之快，在研究微生物群落时必须考虑生态和进化压力。环境因素、物种相互作用和进化动态都对群落的形成起着作用。然而，这些因素中的每一个在驱动微生物群落组成方面的相对贡献仍不清楚。这项研究将结合生态学和进化论的概念，以蜜蜂为模型系统，研究是什么驱动了与动物相关的微生物群落的组成。蜜蜂是解决与动物相关的微生物群落动力学基本问题的理想模型系统，原因有几个：1)蜜蜂肠道内只有几种微生物，2)全世界所有的蜜蜂肠道内都有相同的微生物，3)蜜蜂易于进行实验操作，4)蜜蜂的所有肠道微生物都可以在实验室中培养。这项研究的关键是我们不仅在物种水平(阿尔法和贝塔多样性)，而且在品系水平上捕捉群落动态的能力。人工受精的蜂王将被用来创造受基因控制的蜂群，这些蜂群将用于体内实验(自然和实验室)。将在不同的受控环境条件(即不同的遗传背景和生活方式)下跟踪群落动态，在这些环境条件下，与宿主相关的微生物群落可以发展。结果将决定这些生态因素如何影响微生物组成。微生物竞争或定殖化顺序(即中性或生态位动态)在决定群落组成方面的作用将通过体内共定殖化实验进行评估。将分析微生物群落的全部基因内容(即功能能力)，以检验功能对等假说，这是群落生态学中性理论的基石。此外，还将评估宿主内发生的微进化的程度，以及随着时间的推移这如何影响群落结构。年龄、生活方式和受基因控制的蜜蜂将与确定的群落(不同品系和物种的组合)共同接种，并对品系和群落水平的变化进行临时评估。与大多数在体外条件下对单个生物体进行的微进化研究不同，该项目将跟踪自然微生物群落内的进化过程。总体而言，这项建议将通过整合这两个领域的概念和方法来研究支配宿主相关微生物群落组成的力量，从而在生态学和进化之间架起一座桥梁。这项提议的更广泛影响有三个主要组成部分，这三个组成部分是在一个为少数群体服务的机构的背景下设定的。第一(I)部分是教职员工和学生通过K-12学校之间的正式伙伴关系和非正式外联活动参与和组织外联活动。第二(Ii)部分包括为本科生创造真实的课堂研究体验的课程开发，第三(Iii)部分涉及对科学中代表性不足的少数群体(URM)的研究培训。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

A major question in both ecology and evolution is: what factors shape microbial communities? Understanding the factors that shape microbial communities is important because microbes play key roles in ecosystem function and in human and animal health. Despite numerous studies, our understanding of what drives microbial community assembly, composition, and dynamics are still lacking. Our gap in knowledge is, in large part, due to a lack of integration between the fields of ecology and evolution. Because microbes evolve so quickly both ecological and evolutionary pressures must be considered when studying microbial communities. Environmental factors, species interactions, and evolutionary dynamics all play a role in shaping communities. However, the relative contributions of each of these factors in driving microbial community composition remain unclear. This research will combine concepts of ecology and evolution to investigate what drives the composition of animal-associated microbial communities using the honey bee as a model system. The honey bee is an ideal model system for addressing fundamental questions about animal-associated microbial community dynamics for several reasons: 1) there are only a few microbes that live inside the bee gut, 2) all honey bees worldwide contain the same microbes inside their gut, 3) honey bees are easy to experimentally manipulate, and 4) all gut microbes of honey bees are cultivable in the lab. Key to this research is our ability to capture community dynamics not only at the species level (alpha and beta diversity), but also at the strain level. Artificially inseminated queen bees will be used to create genetically controlled colonies that will be used for in vivo experiments (natural and lab). Community dynamics will be followed across different controlled environmental conditions (i.e. different genetic backgrounds and lifestyles) in which a host-associated microbial community can develop. Results will determine how each of these ecological factors influence microbial composition. The role microbial competition or colonization order (i.e. neutral vs niche dynamics) plays in dictating the community composition will be assessed via in vivo co-colonization experiments. The entire gene content (i.e. functional capabilities) of microbial communities will be analyzed to test the functional equivalency hypothesis, which is at the cornerstone of the neutral theory in community ecology. Additionally, the extent of microevolution that occurs within a host, and how this impacts community structure over time will be evaluated. Age, lifestyle, and genetically controlled bees will be co-inoculated with defined communities (different combinations of strains and species) and temporally assessed for strain and community level changes. Unlike most microevolution studies which are done on single organisms under in vitro conditions, this project will follow evolutionary processes within a natural microbial community. Overall, this proposal will bridge ecology and evolution by integrating concepts and approaches from both fields to investigate the forces that govern the composition of host-associated microbial communities. The broader impacts of this proposal have three major components that are set in the context of an institution that is minority serving. The first (i) component is faculty and student participation in, and organization of, outreach events through formal partnerships between K-12 schools and informal outreach activities. The second (ii) component consist of curriculum development to create authentic classroom research experiences for undergraduates, and the third (iii) component involves research training for underrepresented minorities in science (URM).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.