Molecular Basis of Phytopathogenicity of Pseudomonas solanacearum

青枯假单胞菌植物致病性的分子基础

• 批准号: 9117544
• 负责人: Mark Schell
• 金额: $ 23.04万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-04-01 至 1995-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9117544&HistoricalAwards=false
• 关键词: Molecular; Basis; Phytopathogenicity; Pseudomonas; solanacearum

Pseudomonas solanacearum is an ecologically and economically important phytopathogen causing a lethal wilt disease of over 200 solanaceous plants worldwide. The research proposed investigates biochemical and genetic basis of its pathogenicity, focusing on major extracellular macromolecules. A greater than 10-kb segment (Region I) of the P. solanacearum genome in which insertions simultaneously cause a major decrease in virulence, production of extracellular polysaccharide slime (EPS), and synthesis of two major extracellular proteins (EXPs) has been identified. One objective of the proposed research is to characterize Region I gene products and investigate their involvement in virulence and synthesis of extracellular virulence molecules. This will be accomplished by E. coli maxicell analysis of Region I subclones, TnphoA mutagenesis, and in vitro biochemical and in planta studies of nonpolar isertion mutants of Region I. The gene encoding a major 28-kDa EXP, whose level correlates with EPS levels, will be cloned and similarly analyzed. For the biochemical studies we will first develop methods to detect accumulation of intermediates in EPS synthesis. Expression of Region I depends on two distinct, unlinked loci that encode exported (membrane) proteins, and a locus located 6 kb downstream of Region I; other studies suggest that all these loci control other virulence genes unlinked to Region I. Additional project objectives are characterization of the regulatory proteins by DNA sequence and gene product analysis, exploring crosstalk between them by analysis of Region I expression in multiple mutant background, and investigation of signals affecting virulence gene regulation.

青枯假单胞菌（Pseudomonassolanacearum）是一种生态和经济上 一种重要的植物病原体，可导致200多人死亡的枯萎病 世界各地的茄科植物。 该研究计划调查 其致病性的生化和遗传基础，重点是 主要细胞外大分子。 大于10 kb的片段 在青枯菌基因组的第一区域（区域I）中， 同时导致毒力的大幅下降， 胞外多糖粘液（EPS），以及两种 主要的胞外蛋白（EXP）已被鉴定。 一 本研究的目的是鉴定I区基因 产品，并调查其参与毒力， 合成细胞外毒力分子。 这将是 由E.区域I亚克隆的大肠杆菌maxicell分析， TnphoA诱变以及体外生物化学和植物体内研究 I区非极性分离突变体。 编码基因 主要的28-kDa EXP，其水平与EPS水平相关，将是 克隆并进行类似分析。 对于生化研究，我们将 首先开发检测中间体积累的方法 EPS合成。 区域I的表达取决于两个不同的， 编码输出（膜）蛋白的非连锁基因座，以及 位于区域I下游6 kb;其他研究表明，所有 这些基因座控制与区域I不连锁的其它毒力基因。 其他项目目标是描述 通过DNA序列和基因产物分析， 通过分析区域I表达来探索它们之间的串扰 在多种突变背景下， 影响毒力基因调控。