Arabidopsis basil immunity to human and plant pathogens

描述（由申请人提供）：本研究的长期目标是阐明植物对人类病原体的免疫力和植物对植物病原体的易感性的明显交织的分子基础。我们使用的模式，铜绿假单胞菌/肠出血性大肠杆菌（EHEC）的病理系统进行这项研究。最近的一项研究表明，转基因表达的P. eruginae毒力蛋白AvrPto（一种推定的GT3激活蛋白）抑制了拟南芥中基于细胞壁的细胞外免疫，不仅允许P. eruginae大量繁殖，而且还允许EHEC O 157：H7大量繁殖。在这项研究中要测试的中心假设是：i）植物使用基于细胞壁的免疫力来抵御许多微生物，包括人类病原体，和ii）P. erythingae毒力蛋白通过抑制极化的细胞外囊泡运输（例如，AvrPto）或下调微生物激活的免疫信号转导途径（例如，HopPtoD 2，一种蛋白酪氨酸磷酸酶）。具体目标是：1）人类病原体对拟南芥属细胞壁基细胞外免疫的激活的研究，2）抑制宿主细胞壁基免疫的拟南芥属毒力蛋白的全基因组鉴定，3）阐明AvrPto抑制极化细胞外囊泡运输的机制，4）阐明HopPtoD 2下调免疫相关信号转导途径的机制，和5）使用功能基因组学方法表征拟南芥细胞壁基免疫。将使用分子遗传学、细胞生物学、转基因、显微镜和发病机制方法的组合。拟议的研究不仅有助于了解细菌病原体如何在高等真核生物中引起疾病的基本知识，而且还将深入了解人类病原体对植物的污染和定殖的分子基础，由于食用新鲜蔬菜引起的食物中毒，这些病原体已成为一个主要的公共卫生和生物恐怖问题。

DESCRIPTION (provided by applicant): The long-term goal of this research is to elucidate the apparently intertwined molecular bases of plant immunity to human pathogens and plant susceptibility to plant pathogens. We use the model Arabidopsis-Pseudomonas syringae/enterohemorrhagic Escherichia coli (EHEC) pathosystem for this research. A recent study shows that transgenic expression of P. syringae virulence protein AvrPto (a putative GTPase activating protein) suppresses the cell wall-based extracellular immunity in Arabidopsis, allowing substantial multiplication of not only P. syringae, but also EHEC O157:H7. The central hypotheses to be tested in this research are: i) Plants uses the cell wall-based immunity to ward off many microbes, including human pathogens, and ii) P. syringae virulence proteins suppress this host immunity by either inhibiting polarized extracellular vesicle trafficking (e.g., AvrPto) or down-regulating the microbe-activated immunity signal transduction pathway (e.g., HopPtoD2, a protein tyrosine phosphatase). Specific aims are: 1) Investigation of the activation of Arabidopsis cell wall-based extracellular immunity by human pathogens, 2) Genome wide identification of P. syringae virulence proteins that suppress host cell wall-based immunity, 3) Elucidation of the mechanism by which AvrPto inhibits polarized extracellular vesicle trafficking, 4) Elucidation of the mechanism by which HopPtoD2 down-regulates the immunity-associated signal transduction pathway, and 5) Characterization of Arabidopsis cell wall-based immunity using functional genomic methods. A combination of molecular genetic, cell biological, transgenic, microscopic, and pathogenesis methods will be used. The proposed research will not only contribute to the fundamental knowledge of how bacterial pathogens cause disease in higher eukaryotes, but also will provide insight into the poorly understood molecular basis of contamination and colonization of plants by human pathogens, which have become a major public health and bioterror concern due to food poisoning from consuming fresh vegetable foods.