DISSERTATION RESEARCH: Pathogen Interaction in a Forest Ecosystem: Sympatric Phytophthora Pathogens in the 'Sudden Oak death' epidemic

在美国西海岸，一种侵入性卵菌病原体，疫霉（Phytophthora ramorum），目前正在生态重要的森林环境中造成高感染率和高死亡率。由这种病原体引起的一种致命疾病被称为“橡树猝死病”。ramorum与另外两种最近描述的致病疫霉物种共享寄主植物和地理范围。一些宿主的并发感染和这些病原体的相似分布表明，它们可能与毒性更强的拉氏疟原虫相互作用，以增强或抑制感染。这种互动对于理解和模拟美国具有潜在的重要意义“橡树猝死”流行病该项目的目标是测试这三种病原体是否在月桂树叶感染中竞争——月桂是一种宿主树，对所有三种物种共同的疾病传播具有重要意义。实验设计结合了宿主、病原体和环境的变化对相互作用结果的影响。这种变异性在病原体竞争研究中经常被排除在外。因此，这些结果不仅将阐明对拉氏疟原虫病的影响，而且更广泛地说，将有助于探索其他宿主/病原体系统中的多物种感染动态。研究结果将广泛传播，并有助于疾病建模、疾病管理和社区外展的跨学科合作。

On the west coast of the United States, an invasive oomycete pathogen, Phytophthora ramorum, is currently causing high infection and mortality rates in ecologically important forest environments. One lethal disease caused by this pathogen has been dubbed "sudden oak death". P. ramorum shares host-plant and geographic ranges with two other recently described pathogenic Phytophthora species. Concurrent infection of some hosts and similar distributions of these pathogens suggest they may interact with the more virulent P. ramorum to enhance or inhibit infection. Such interactions are potentially important for understanding and modeling the U.S. "sudden oak death" epidemic. The goal of this project is to test whether these three pathogens compete in leaf infections of bay laurel - a host tree significant for disease transmission that is common to all three species. The experimental design incorporates effects of variability in the host, pathogen and environment on interaction outcome. This variability is often excluded in pathogen competition studies. Thus, results will not only elucidate effects on P. ramorum disease, but more broadly, will assist in exploring multi-species infection dynamics in other host/pathogen systems. Study findings will be widely disseminated and contribute to interdisciplinary collaborations for disease modeling, disease management and community outreach.