Collaborative Research: Sudden Oak Death: Feedback Between a Generalist Pathogen, Hosts, and Heterogeneous Environments at Multiple Spatial and Temporal Scales

合作研究：橡树猝死：多种时空尺度上的通用病原体、宿主和异质环境之间的反馈

• 批准号: 0622770
• 负责人: David Rizzo
• 金额: $ 75.01万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0622770&HistoricalAwards=false
• 关键词: Collaborative; Research; Sudden; Oak; Death

Sudden Oak Death (SOD), caused by the fungal-like pathogen Phytophthora ramorum, is the latest in a long line of exotic forest diseases that includes chestnut blight and Dutch elm disease. Potentially millions of tanoak and oak trees in coastal forests of California and Oregon have been lost to SOD over the past 10 years. This project will examine the environmental and biological circumstances that initially led to the emergence of P. ramorum and the subsequent disease-related changes to the forest environment. We will use a combination of field, greenhouse, and laboratory experiments along with geographical information system (GIS) and mathematical modeling approaches to research the spatial and temporal dynamics of SOD. The project will examine how human-induced changes in landscape structure and composition of forests when combined with weather patterns (e.g., El Nino) may have influenced the establishment and spread of pathogen in California forests. Following P. ramorum invasion, changes may also occur to the pathogen, host and forest environment. P. ramorum is a generalist pathogen that infects plants in over 45 genera including ferns, gymnosperms, monocots and dicots. SOD epidemics in California forests are primarily driven by the presence of these associated host species that serve as sources of the pathogen, and not by the oaks themselves. Because mortality is often restricted to oak and tanoak, the broad host range of P. ramorum will allow us to test hypotheses of plant competition mediated by a pathogen. The broad host range of the pathogen may also allow for P. ramorum populations to evolve towards increased virulence and/or increased diversity. However, over time we would also expect that invasion by P. ramorum will influence the occurrence and spatial distribution of resistant and tolerant host genotypes. Finally, the role of parasites in influencing ecosystem functioning (e.g., nutrient cycling) has often been overlooked. In areas where P. ramorum-associated overstory mortality has significantly impacted composition of coastal forests, we will analyze changes in forest floor inputs, organic matter, decomposition rates, and nitrogen dynamics. A better understanding of invasion processes and impacts of generalist pathogens is critical for developing management and regulatory strategies to protect natural ecosystems. This research will have a number of broad impacts in disease policy and management, publicoutreach, and education. A better understanding of invasion processes and impacts of generalist pathogens is critical for developing management and regulatory strategies to protect natural ecosystems. The PIs are actively involved with advising state, Federal (APHIS) and International committees on SOD and other forest diseases. P. ramorum has the broadest host range of any fungal pathogen ever attempted to be quarantined and will serve as a model for responses to future pathogen introductions. The project will also support the education of 4 graduate students, 3 post-docs as well as a number of undergraduate students. Each lab has a history of including under-represented groups. As part of their education, post-docs and graduate students will be involved in public outreach efforts. Pre-existing collaborations on research and management of SOD will be continued with several Native American tribes (Pomo, Hoopa, and Yurok) in Northern California.

橡树猝死病（SOD）是由真菌样病原体疫霉（Phytophthora ramorum）引起的，是一长串外来森林疾病（包括栗树疫病和荷兰榆树病）中最新的一种。在过去的10年里，加州和俄勒冈州沿海森林中可能有数百万棵紫杉树和橡树因SOD而消失。该项目将审查最初导致黑桫椤出现的环境和生物情况以及随后与疾病有关的森林环境变化。我们将结合田间、温室和实验室实验，以及地理信息系统（GIS）和数学建模方法来研究SOD的时空动态。该项目将审查人类引起的森林景观结构和组成的变化与天气模式（如厄尔尼诺现象）相结合时可能如何影响加利福尼亚森林中病原体的形成和传播。在黑桫椤入侵后，病原菌、寄主和森林环境也会发生变化。ramorum是一种广泛性病原菌，可侵染蕨类植物、裸子植物、单子叶植物和双子叶植物等45属植物。加州森林中SOD的流行主要是由这些作为病原体来源的相关宿主物种的存在驱动的，而不是由橡树本身驱动的。由于死亡率通常仅限于橡树和tanoak，因此ramorum的广泛寄主范围将使我们能够测试由病原体介导的植物竞争的假设。病原菌广泛的寄主范围也可能使雷氏疟原虫种群朝着增强毒力和/或增强多样性的方向进化。然而，随着时间的推移，我们还预计拉氏疟原虫的入侵将影响耐药和耐药宿主基因型的发生和空间分布。最后，寄生虫在影响生态系统功能（如养分循环）方面的作用常常被忽视。在与黑桫椤相关的上层植被死亡率显著影响沿海森林组成的地区，我们将分析森林地面投入、有机质、分解率和氮动态的变化。更好地了解多面手病原体的入侵过程和影响对于制定保护自然生态系统的管理和监管策略至关重要。这项研究将对疾病政策和管理、公共宣传和教育产生许多广泛的影响。更好地了解多面手病原体的入侵过程和影响对于制定保护自然生态系统的管理和监管策略至关重要。这些机构积极参与就SOD和其他森林疾病向州、联邦和国际委员会提供咨询。在任何试图被隔离的真菌病原体中，拉氏假单胞菌具有最广泛的宿主范围，并将作为对未来病原体引入的反应的模型。本项目还将资助培养4名研究生、3名博士后和若干名本科生。每个实验室都有纳入弱势群体的历史。作为他们教育的一部分，博士后和研究生将参与公共宣传工作。将继续与北加州的几个美洲土著部落（Pomo、Hoopa和Yurok）在SOD研究和管理方面已有的合作。