Stomate-based innate immunity against bacterial infection in Arabidopsis

描述(申请人提供)：动植物的先天免疫可被高度保守的病原体/微生物相关分子模式(PAMPs/MAMPs)激活，如细菌鞭毛蛋白和脂多糖(LPS)。最近的研究表明，植物的气孔，即植物表皮上的毛孔，在抵抗细菌进入植物的先天免疫中起着作用。具体地说，气孔关闭对大肠杆菌O157：H7和紫丁香假单胞菌PV的反应。番茄(PST)DC3000或细菌PAMPs。保卫细胞对PAMPs的感知需要鞭毛受体以及植物激素脱落酸和水杨酸的产生和信号传递。保卫细胞是形成气孔孔的一对细胞。植物病原菌PST DC3000产生冠状毒素(COR)来抑制气孔关闭作为一种致病策略。总而言之，这些结果表明，气孔在调节植物与植物和叶圈(叶表面)中的人类病原细菌的相互作用中发挥着重要作用。 该项目的长期目标是阐明导致气孔防御的信号转导途径，并剖析细菌毒素COR抑制这种新的寄主防御的机制。需要检验的中心假设是：(I)气孔防御是植物自然免疫反应的组成部分，以限制细菌(包括人类病原菌)的进入；(Ii)植物病原体必须依靠特定的毒力因子或环境条件来抑制气孔防御，才能成功。将使用一种综合的方法，包括分子遗传学、显微镜、生化和发病机制分析。这项研究将有助于加深对植物先天免疫和细菌致病机理的基础知识，并将加深我们对植物-人类病原菌在叶圈中相互作用的分子基础的理解。人类对新鲜蔬菜的病原体污染是一个重大的公共卫生问题，也是一个潜在的生物恐怖威胁，是食物中毒的一个来源。 公共卫生相关性：本提案描述了模式植物拟南芥对植物和人类病原菌的天然免疫的分子基础的基础研究。人类病原体对食品的污染是公众健康的主要问题。这项研究有可能从机理上了解新鲜农产品的植物防御和人类病原体污染，并指导未来制定适当的预防措施。

DESCRIPTION (provided by applicant): Innate immunity in animals and plants can be activated by highly conserved pathogen/microbe- associated molecular patterns (PAMPs/MAMPs), such as bacterial flagellin and lipopolysaccharides (LPSs). Recent studies provide evidence that plant stomata, pores in the epidermis of plants, function in innate immunity against the entry of bacteria into the plant. Specifically, stomata close in response to Escherichia coli O157:H7 and Pseudomonas syringae pv. tomato (Pst) DC3000 or bacterial PAMPs. Perception of PAMPs by guard cells, the pair of cells that forms the stomatal pore, requires a flagellin receptor as well as production and signaling of the plant hormones abscisic acid and salicylic acid. The virulent plant pathogen Pst DC3000 produces the phytotoxin coronatine (COR) to suppress stomatal closure as a virulence strategy. Collectively, these results suggest an important role of stomata in modulating the interactions of plants with plant and human pathogenic bacteria in the phyllosphere (the leaf surface). The long-term goal of this project is to elucidate the signal transduction pathway leading to stomate- based defense and to dissect the mechanism by which the bacterial toxin COR inhibits this novel host defense. The central hypotheses to be tested are that (i) stomate-based defense is an integral part of the plant's natural immune response to restrict the entry of bacteria, including human pathogenic bacteria, and (ii) to be successful, plant pathogens must rely on specific virulence factors or environmental conditions to suppress stomate-based defense. An integrative approach involving molecular genetics, microscopy, and biochemical and pathogenesis assays will be used. The proposed research will contribute to the fundamental knowledge of innate immunity and bacterial pathogenesis in plants and will increase our understanding of the molecular basis of plant-human pathogen interactions in the phyllosphere. Human pathogen contamination of fresh vegetables is a major public health concern and a potential bio-terrorist threat as a source of food poisoning. PUBLIC HEALTH RELEVANCE: This proposal describes basic research on the molecular basis of innate immunity of the model plant Arabidopsis to plant and human pathogenic bacteria. Food contamination with human pathogens is a major concern to public health. This research has the potential to provide a mechanistic understanding of plant defense and human pathogen contamination of fresh produce and to guide future development of appropriate prevention measures.