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

生态学和进化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和人类和动物健康中起着关键作用。尽管进行了大量的研究，但我们对驱动微生物群落组装、组成和动态的理解仍然缺乏。我们在知识上的差距在很大程度上是由于缺乏生态学和进化领域之间的整合。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在形成群落中发挥作用。然而，这些因素在驱动微生物群落组成中的相对贡献尚不清楚。这项研究将结合生态学和进化的概念，以蜜蜂为模型系统来研究是什么驱动了动物相关微生物群落的组成。蜜蜂是解决与动物相关的微生物群落动态基本问题的理想模型系统，原因如下：1)只有少数微生物生活在蜜蜂肠道内；2)全世界所有蜜蜂的肠道内都含有相同的微生物；3)蜜蜂易于实验操作；4)所有蜜蜂的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能够在物种水平（α和β多样性）上捕捉群落动态，而且还能在品系水平上捕捉群落动态。人工授精的蜂王将被用来创造基因控制的蜂群，这些蜂群将用于体内实验（自然和实验室）。群落动态将遵循不同的受控环境条件（即不同的遗传背景和生活方式），在这些条件下，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。微生物竞争或定殖顺序（即中性与生态位动态）在决定群落组成中的作用将通过体内共定殖实验进行评估。我们将分析微生物群落的整个基因含量（即功能能力），以检验功能等效假说，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程度，以及随着时间的推移，微进化如何影响群落结构。年龄、生活方式和基因控制的蜜蜂将与确定的群落（不同菌株和物种的组合）共同接种，并暂时评估菌株和群落水平的变化。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，该项目将遵循天然微生物群落内的进化过程。总的来说，该提案将通过整合这两个领域的概念和方法来研究控制宿主相关微生物群落组成的力量，从而架起生态学和进化的桥梁。该提案的广泛影响有三个主要组成部分，这些组成部分是在一个为少数民族服务的机构的背景下设定的。第一个组成部分是教师和学生通过K-12学校之间的正式伙伴关系和非正式的外展活动参与和组织外展活动。第二（ii）部分包括课程开发，为本科生创造真实的课堂研究体验，第三（iii）部分涉及对科学领域代表性不足的少数群体（URM）的研究培训。该奖项反映了美国国家科学基金会的法定使命，并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，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.