Isolation and Characterization of Pseudomonas Type III Effectors That Suppress Programmed Cell Death in Eukaryotes

抑制真核生物程序性细胞死亡的 III 型假单胞菌效应子的分离和表征

• 批准号: 0317165
• 负责人: James Alfano
• 金额: $ 37.5万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0317165&HistoricalAwards=false
• 关键词: Isolation; Characterization; Pseudomonas; Type; III

Pseudomonas syringae is a pathogen whose interactions with plants can take two strikingly different courses. In virulent interactions with susceptible plants, bacteria cause disease, whereas in avirulent interactions with resistant plants, bacteria trigger a rapid, defense-associated programmed cell death (PCD) known as the hypersensitive response (HR). Both outcomes are controlled by bacterial proteins injected into plant cells by a protein delivery system called the type III secretion system (TTSS). Preliminary data on this project show that several bacterial proteins act as suppressors of the HR. Remarkably, these PCD suppressors also function to inhibit yeast apoptosis (a type of PCD found in animals) and inhibit the ability of the mouse pro-apoptotic protein, Bax, to induce apoptosis in plants and yeast. This indicates that these proteins function as anti-apoptotic factors in a trans-kingdom manner. This project will use screens in yeast and plant systems to isolate additional bacterial proteins that act as PCD suppressors. Moreover, the project will characterize each suppressor to determine their general effect on other hallmarks of plant defense. The experiments described in this project offer broad training for students. Besides current approaches in microbiology, plant biology, and functional genomics, the topics pursued have important ramifications for mammalian systems, greatly adding to the breadth of this research program. The researchers have participated with the establishment of the UNL Young Nebraska Scientist (YNS) program, designed to enhance the recruitment of minority high school students who have demonstrated interest in the life sciences. The program is unusual in that it provides mentorship to the student from high school through their undergraduate career. Also, the researchers have initiated collaboration with Nebraska Wesleyan University, an excellent liberal arts college. Thus, the research group will enhance its pool of undergraduates, many of which are from under-represented ethnic groups.

丁香假单胞菌是一种病原体，它与植物的相互作用可以采取两种截然不同的过程。在与易感植物的毒性相互作用中，细菌引起疾病，而在与抗性植物的无毒相互作用中，细菌引发快速的防御相关的程序性细胞死亡（PCD），即超敏反应（HR）。这两种结果都是由被称为III型分泌系统（TTSS）的蛋白质传递系统注入植物细胞的细菌蛋白质控制的。该项目的初步数据表明，几种细菌蛋白可作为HR的抑制因子。值得注意的是，这些PCD抑制因子还能抑制酵母细胞凋亡（动物中发现的一种PCD），并抑制小鼠促凋亡蛋白Bax诱导植物和酵母细胞凋亡的能力。这表明这些蛋白以跨界方式发挥抗凋亡因子的作用。该项目将在酵母和植物系统中使用筛选来分离作为PCD抑制因子的其他细菌蛋白质。此外，该项目将描述每个抑制因子，以确定它们对植物防御的其他标志的一般影响。本项目所描述的实验为学生提供了广泛的训练。除了目前的微生物学、植物生物学和功能基因组学方法外，所追求的主题对哺乳动物系统具有重要的影响，极大地增加了本研究计划的广度。研究人员参与了UNL内布拉斯加州青年科学家（YNS）计划的建立，该计划旨在加强对生命科学表现出兴趣的少数民族高中生的招募。该项目的不同寻常之处在于，它为学生提供从高中到本科的指导。此外，研究人员还开始与内布拉斯加州卫斯理大学合作，这是一所优秀的文理学院。因此，该研究小组将增加其本科生的数量，其中许多来自代表性不足的少数民族。