丁香假单胞菌番茄变种隐含的saxE基因影响病菌定植及致病性的分子机理

项目名称： 丁香假单胞菌番茄变种隐含的saxE基因影响病菌定植及致病性的分子机理

项目编号： No.31272006

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 农业科学

项目作者： 范军

作者单位： 中国农业大学

项目金额： 75万元

中文摘要： 丁香假单胞菌是具有重要经济意义的植物病原细菌之一，其番茄致病变种作为模式病原菌被广泛用于研究细菌与植物相互作用的机理。通过转座子突变方法我们获得了一个对植物提取物敏感的丁香假单胞菌突变体。该突变体在丰富培养基中的生长与野生型没有显著差异，但在含有植物提取物的培养基或侵染寄主植物时生长受到显著抑制，致病性也明显减弱。分析显示突变表型是由一个隐含基因（saxE）失活造成。本项目将立足这一新的发现，研究植物或其提取物中对saxE缺陷型菌株产生抑制作用的物质基础，并分析此物质在植物先天性免疫反应中所扮演的角色；同时本研究将解析此物质抑制saxE缺陷型菌株生长及致病作用的分子机制以及SaxE蛋白如何保护病原菌免受植物因子的抑制。本研究综合运用遗传学，植物化学以及分子生物学等多种方法解析植物和病原细菌互作双方的效应因子，将为深入了解植物- - 病原物互作的分子基础和未来农作物抗病性改良提供参考。

中文关键词： 丁香假单胞菌；大肠菌素M；细菌素；致病性；钙离子

英文摘要： Pseudomonas syringae is one of several bacterial species that cause diseases on some economically important crops. P.syringae pv. tomato has been intensively used as a model pathogen to study molecular basis of plant-pathogen interaction.By transposon mutagenesis of this pathogenic bacteria, we have obtained a mutant strain that is sensitive to extracts derived from host plant. The virulence of the mutant bacteria is significantly reduced and its growth is strongly suppressed in planta or in rich media supplemented with plat extracts, but not in media without addition of the extracts. Molecular characterization of the transposon insertion shows that the mutant phenotype is caused by loss-of-function of a cryptic gene, saxE. Based on these observations, the proposed research aims to understand the identity of the growth-inhibiting factor and its role in plant innate immunity to bacterial infection. In parallel, we will investigate the molecular mechanisms underlying this suppression effect in saxE-defecient bacteria and how saxE protein protects bacteria against the inhibitory effect. The proposed researh integrates multi-disciplinary methods to dissect effectors derived from both sides of the plant-bacteria interaction, which may lead to new insight on the fundamental biology and will inform future work on impro

英文关键词： Pseudomonas syringae；colicin M；bacteriocin；pathogenicity；calcium