Collaborative Research: Field and Modeling Studies in Support of Understanding Disease Resistance in Estuarine Populations and Response to Climate Change

与陆地生态系统相比，海洋生态系统中宿主-寄生虫相互作用的研究很少。许多商业开发的双壳类物种患有寄生虫病，了解宿主-寄生虫对气候变化的反应对这些渔业的管理具有重要意义。来自老道明大学和罗格斯大学的一个研究小组将研究东方牡蛎（Crassostrea virginica）的宿主-寄生虫关系，这种牡蛎患有两种致命的原生动物疾病，MSX和Dermo。该团队将把特拉华湾环境波动、牡蛎种群结构和两种致命寄生虫的大量长期数据整合到耦合的生物和海洋学数值模型中，以预测气候变化如何影响宿主-寄生虫关系。结果将改善对宿主遗传和种群动态以及环境如何与疾病生物体相互作用以构建宿主种群的理解，以及气候变化如何影响这些相互关联的过程。他们将重点关注：1)疾病避难所的作用，2)每年繁殖后代的亲本（抗病或不抗病）数量变化的影响，3)环境调节的选择和传播过程在宿主种群中产生遗传变化中的作用，以及4)牡蛎-寄生虫相互作用对气候变化的反应及其对宿主种群遗传结构的后续影响。通过实验室和实地研究，他们将确定与MSX和皮肤病抗性相关的其他基因，并确定来自假定的避难所和高疾病地区的牡蛎之间可能的表型和基因型差异。此外，它们将确定疾病避难所的存在是因为低传播率还是因为环境抑制了感染的发展。最后，他们将评估产卵种群有效规模的时空变化，以及牡蛎种群中是否发生了“抽奖”繁殖事件。来自这些研究的数据将支持包括显性遗传结构、疾病过程和牡蛎种群动态在内的模型。循环-生物地球化学模型将为牡蛎模型提供环境条件，并允许测试寄生虫和幼虫运输以及当前和未来气候条件对宿主种群结构的影响。该项目的更广泛影响包括提高对疾病如何构成具有重要商业价值的河口物种种群的理解。该项目还将有助于在解决渔业面临的许多重要问题所需的各种学科（遗传学、病理学、基因组学、生物信息学、种群建模）方面培训学生。该项目的成果将通过科学会议、在同行评议的文献和网站上发表，以及通过正在进行的加强当地学校普通科学教育的外联努力来传播。

Host-parasite interactions in marine ecosystems are poorly studied compared to those in terrestrial systems. Many commercially exploited bivalve species experience parasitic diseases, and understanding host-parasite responses to climate change has implications for management of these fisheries. A team from Old Dominion University and Rutgers University will investigate host-parasite relationships in the eastern oyster (Crassostrea virginica), which suffers from two lethal protozoan diseases, MSX and Dermo. The team will integrate a wealth of long-term data on environmental fluctuation in Delaware Bay, the structure of its oyster population and two lethal parasites into coupled biological and oceanographic numerical models to predict how climate change may affect the host-parasite relationship. The result will be improved understanding how host genetics and population dynamics, and environment interact with disease organisms to structure host populations, and how climate change may affect these inter-related processes. They will focus on: 1) the role of disease refugia, 2) the effect of variability in the number of parents (disease-resistant or not) that reproduce offspring each year, 3) the role of environmentally-modulated selection and transmission processes in producing genetic changes in the host population, and 4) the response of the oyster-parasite interaction to climate change and consequent effects on overall host population genetic structure. Using laboratory and field studies, they will identify additional genes linked to MSX and Dermo disease resistance, and identify possible phenotypic and genotypic differences between oysters from putative refugia and high-disease areas. In addition, they will determine whether disease refugia exist because of low transmission rates or because environment inhibits infection development. Finally, they will assess spatial and temporal variability in the effective size of the spawning populations and whether "sweepstakes" reproductive events occur in oyster populations. The data from these studies will underpin models that include explicit genetic structure, disease processes, and oyster population dynamics. A circulation-biogeochemical model will provide environmental conditions for the oyster models, and allow testing of the effects of parasite and larval transport, and current and future climate conditions on host population structure. The broader impacts of the project include improved understanding of how diseases structure populations of a commercially important estuarine species. This project will also contribute to training of students in the variety of disciplines (genetics, pathology, genomics, bioinformatics, population modeling) needed to solve many of the important problems facing fisheries. Results from this project will be disseminated through scientific conferences, publication in the peer reviewed literature and web sites, and through ongoing outreach efforts to enhance general science education at local schools.