Interception of the Fungal Haustorium by the Broad-Spectrum Plant Resistance Protein RPW8

这个奖项是根据2009年美国复苏和再投资法案(公共法律111-5)资助的。许多真菌和类似真菌的卵菌病原体突破植物细胞壁，形成一种名为吸器的摄食结构，从宿主细胞窃取光合作用。吸器被一层神秘的吸器外膜(EHM)包裹，据信来自寄主细胞质膜。虽然这种界面膜对宿主的防御和致病的病原体至关重要，但直到最近还没有鉴定出单一的EHM驻留蛋白。来自PI小组的初步数据现在表明，广谱抗病蛋白RPW8.2专门针对EHM，用于防御Golovinmyces spp.会引起广泛传播的白粉病。本项目旨在表征RPW8.2与其防御和细胞内转运活动有关的结构-功能关系。RPW8.2从其合成部位到EHM的转运途径将通过药理学、生化和遗传学方法加以阐明，并将确定14-3-3蛋白在这一过程中的作用。通过对RPW8.2介导的广谱霉病抗性的分析，该项目将为植物和病原体之间的分子战争提供新的见解。特别是，作为宿主天然免疫的重要组成部分，将分析靶向蛋白运输的细胞机制。该项目将描述的基本机制可能会为设计更有效、更集中的防御系统来对抗大量吸器形成真菌和卵菌病原体开辟新的途径，从而在作物生产和环境保护方面取得进展。此外，拟议的项目将通过为植物遗传学和分子植物病理学方面的高中实习生、本科生、研究生和博士后研究人员提供理想的动手培训机会，将研究与教育相结合。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Many fungal and fungus-like oomycete pathogens breach the plant cell wall and develop a feeding structure named the haustorium to steal photosynthate from the host cell. The haustorium is encased by an enigmatic extra-haustorial membrane (EHM) believed to be derived from the host cell plasma membrane. Although this interfacial membrane is of critical importance to the host for defense and the pathogen for pathogenesis, until recently not a single EHM-resident protein has been identified. Preliminary data from the PI's group now demonstrate that the broad-spectrum disease resistance protein RPW8.2 is specifically targeted to the EHM for defense against isolates of Golovinomyces spp. that cause wide-spread powdery mildew diseases. This project aims to characterize the structure-function relationships of RPW8.2 in relation to its defense and intracellular trafficking activities. The trafficking pathway of RPW8.2 from its site of synthesis to the EHM will be elucidated via pharmacological, biochemical and genetic approaches and the role of a 14-3-3 protein in this process will be determined. Through its analysis of RPW8.2-mediated broad-spectrum mildew resistance, this project will provide fresh insights into the molecular warfare between plants and pathogens. In particular, cellular mechanisms of targeted protein trafficking will be analyzed as an important component of host innate immunity. The basic mechanisms to be characterized in this project may open new avenues for engineering more effective, focused defense systems against numerous haustorium-forming fungal and oomycete pathogens, thereby leading to gains in crop production and environmental protection. Furthermore, the proposed project will integrate research with education by providing ideal hands-on training opportunities for high school internship students, undergraduates, graduates, and postdoctoral researchers in plant genetics and molecular plant pathology.