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

该项目研究外部环境如何塑造免疫系统。海马为研究宿主-微生物相互作用提供了理想的模型，原因有三。它们免疫系统的遗传结构很简单。此外，它们的扩散能力有限，而且它们的地理分布很广。之前对新西兰和澳大利亚东南部的大肚海马的研究发现，与免疫反应相关的基因组部分的遗传多样性模式与未被选择的基因组部分之间存在显着差异。该提案旨在通过实验测试宿主微生物协会的现场观察。它将解决宿主-微生物协同进化理论中的一个关键问题：自然种群中的宿主-微生物协会是一种局部免疫适应吗？海洋环境为食物、运输、商业和娱乐提供了一个重要的经济引擎，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仍然缺乏了解。这项研究的结果将被纳入NSF资助的微生物学真实研究经验计划，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商业渔业服务和国家水和大气研究所为海洋保护规划和管理提供信息。该项目将通过测试海洋物种腹海马（大肚海马）中宿主-微生物协会的适应性后果，评估主要组织相容性II类基因座（MHII）局部适应的潜在机制。野生H. abdominalis在其地理范围内检测到增强水平的MHII变异在人口水平上相对于中性位点。宿主肠道微生物组的测序表明，当地环境（城市，农业或原始）对从这些地点收集的宿主的微生物组成有显着影响。H. abdominalis将暴露于与自然群体中的宿主显示阳性、阴性或中性关联的微生物，并且将测量MHII基因型对生长、状况、免疫应答和存活的影响。这里提出的研究代表了一个令人兴奋的机会，明确测试宿主-微生物协会的实地观察，并使用反映微生物暴露的自然途径的实验方案，针对一个关键的进化概念，微生物介导的局部适应

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