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

与陆地系统相比，海洋生态系统中宿主-寄生虫的相互作用研究较少。许多商业开发的双壳类物种都患有寄生虫病，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团队将调查患有两种致命原生动物疾病MSX和Dermo的东方牡蛎(Crassostrea Virgiica)的宿主和寄生虫之间的关系。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生物和海洋数值模型中，以预测气候变化可能如何影响宿主和寄生虫的关系。其结果将是更好地理解宿主遗传学和种群动态，以及环境如何与疾病有机体相互作用以构建宿主种群结构，以及气候变化可能如何影响这些相互关联的过程。他们将集中于：1)疾病避难所的作用，2)每年繁殖后代的亲本数量(抗病与否)的变化的影响，3)环境调节的选择和传递过程在宿主种群中产生遗传变化的作用，以及4)牡蛎和寄生虫相互作用对气候变化的反应以及由此对整个宿主种群遗传结构的影响。通过实验室和实地研究，他们将识别与MSX和皮尔莫疾病抗性有关的其他基因，并识别可能来自避难所和高发区的牡蛎之间可能的表型和基因差异。此外，他们将确定疾病避难所的存在是因为传播率低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的有效规模的空间和时间变异性，以及牡蛎种群中是否发生“抽奖”繁殖事件。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的影响，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更好地了解疾病如何构成具有重要商业价值的河口物种的种群结构。该项目还将有助于对学生进行各种学科(遗传学、病理学、基因组学、生物信息学、种群建模)的培训，以解决渔业面临的许多重要问题。这一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为加强当地学校的一般科学教育而持续开展的宣传活动来传播。

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.