DISSERTATION RESEARCH: Isolating a Mechanism for Microbial-Host Local Adaptation

这个项目研究外部环境是如何塑造免疫系统的。海马为研究宿主与微生物的相互作用提供了一个理想的模型，原因有三。它们免疫系统的基因结构很简单。它们的扩散能力有限，地理分布广泛。先前对分布在新西兰和澳大利亚东南部的大肚海马进行的研究发现，与免疫反应相关的基因组部分的遗传多样性模式与未经过选择的基因组部分的遗传多样性模式存在显著差异。本研究旨在对宿主-微生物关联的实地观察结果进行实验验证。它将解决宿主-微生物共同进化理论中的一个关键问题：自然种群中的宿主-微生物关联是一种局部免疫适应吗？海洋环境为食物、运输、商业和娱乐提供了重要的经济引擎，但我们对人类活动如何影响常驻生物和影响生态系统健康的理解仍然很差。这项研究的结果将被纳入美国国家科学基金会资助的微生物学真实研究经验项目，为纽约城市大学10个校区的学生提供服务，并将通过初级产业部、FishServe商业渔业服务部门和国家水与大气研究所为海洋保护规划和管理提供信息。宿主-微生物相互作用是一种未被充分认识的适应驱动因素。本项目将通过测试海洋物种海马腹部（大肚海马）宿主-微生物关联的适应度结果，评估主要组织相容性II类位点（MHII）的潜在局部适应机制。以往对野生腹腹鼠地理范围的研究发现，相对于中性位点，种群水平上的MHII变异性水平有所提高。宿主肠道微生物组的测序表明，当地环境（城市、农业或原始环境）对从这些地点收集的宿主的微生物组成有显著影响。实验群体将暴露于与自然群体宿主呈阳性、阴性或中性关联的微生物中，并测量MHII基因型对生长、状况、免疫反应和生存的影响。这里提出的研究代表了一个令人兴奋的机会，可以明确测试宿主-微生物关联的现场观察结果，并针对一个关键的进化概念，微生物介导的局部适应，使用反映微生物暴露自然途径的实验方案

This project investigates how the external environment shapes the immune system. Seahorses provide an ideal model for studying host-microbe interactions for three reasons. The genetic structure of their immune system is simple. Also, their dispersal capability is limited, and their geographic distribution is broad. Previous research on the pot-bellied seahorse across its range in New Zealand and southeastern Australia found striking differences between the pattern of genetic diversity in those parts of the genome related to immune response versus those parts of the genome that are not under selection. This proposal aims to experimentally test field observations of host-microbe associations. It will address a key question in host-microbial co-evolutionary theory: Are host-microbe associations in natural populations a type of local adaptation for immunity? Marine environments provide an essential economic engine for food, transportation, commerce and recreation, but we still have a poor understanding of how human activities impact resident organisms and influence ecosystem health. The results of this research will be incorporated into the NSF-funded Authentic Research Experience in Microbiology program serving students at ten City University of New York campuses, and will inform marine conservation planning and management through the Ministry of Primary Industries, FishServe Commercial Fisheries Services, and the National Institute of Water and Atmospheric Research.Host-microbe interactions are an underappreciated driver of adaptation. This project will evaluate a potential mechanism of local adaptation at the major histocompatibility class II locus (MHII) by testing the fitness consequences of host-microbe associations in the marine species Hippocampus abdominalis (the pot-bellied seahorse). Previous research on wild H. abdominalis across its geographic range detected enhanced levels of MHII variability at the population level relative to neutral loci. Sequencing of the host gut microbiome indicates that the local environment (urban, agricultural, or pristine) has a significant effect on the microbial composition of hosts collected from these sites. Experimental populations of H. abdominalis will be exposed to microbes showing positive, negative, or neutral associations with hosts in natural populations, and effects of MHII genotype on growth, condition, immune response and survival will be measured. The research proposed here represents an exciting opportunity to explicitly test field observations of host-microbe associations and targets a key evolutionary concept, microbe-mediated local adaptation, using an experimental protocol reflecting natural pathways of microbial exposure