绿针假单胞菌GP72中aurI/aurR系统调控功能
aurI/aurR system regulatory function in Pseudomonas chlororaphis GP72
  
DOI:  10.13344/j.microbiol.china.180240
中文关键词:绿针假单胞菌GP72,aurI/aurR双元调控系统,吩嗪类化合物,群体感应
英文关键词:Pseudomonas chlororaphis GP72, aurI/aurR regulatory system, phenazine, quorum sensing
基金项目:国家自然科学基金(31670033)
作者单位E-mail
马润亭 上海交通大学生命科学技术学院 微生物代谢国家重点实验室 上海 200240  
郭树奇 上海交通大学生命科学技术学院 微生物代谢国家重点实验室 上海 200240  
王威 上海交通大学生命科学技术学院 微生物代谢国家重点实验室 上海 200240  
张雪洪 上海交通大学生命科学技术学院 微生物代谢国家重点实验室 上海 200240 xuehzhang@sjtu.edu.cn 
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中文摘要:
      【背景】绿针假单胞菌(Pseudomonas chlororaphis) GP72是一株可生产吩嗪类抗生素吩嗪-1-羧酸(PCA)和2-羟基吩嗪(2-OH-PHZ)的生防根际促生菌。基因组比对发现GP72菌中存在aurI/aurR双元调控系统。【目的】研究该系统对GP72中吩嗪类物质的调控作用。【方法】将aurI基因在大肠杆菌中异源表达,用紫色杆菌CV026和根癌农杆菌NTL4做显色实验。构建基因敲除菌株和回补菌株,发酵测量突变株的生长曲线与总吩嗪产量。构建转录融合质粒,测定吩嗪合成基因启动子的转录水平。【结果】显色实验显示,aurI能产生多种信号分子,使CV026显紫色、NTL4显蓝色。分别单独敲除aurI和aurR基因,同时敲除aurI/aurR基因,吩嗪产量均会升高,而回补菌株吩嗪产量降为野生型水平。β-半乳糖苷酶活性测定结果显示,突变株的酶活比野生型高。【结论】aurI/aurR负调控GP72的吩嗪合成,通过抑制吩嗪合成启动子的转录而影响吩嗪类物质的产量。
英文摘要:
      [Background] Pseudomonas chlororaphis GP72 is a rhizobacteriaum that could produce phenazine antibiotics containing phenazine-1-carboxylic acid (PCA) and 2-hydroxyphenazine (2-OH-PHZ). Based on analyzing the whole-genome sequence, aurI/aurR regulatory system was found existed in GP72. [Objective] This article aims to study the regulation of aurI/aurR on phenazine production in GP72. [Methods] The aurI gene was heterologously expressed in Escherichia coli, then Chromobacterium violaceum CV026 and Agrobacterium tumefaciens NTL4 were used in plate assays. The knockout strains and complemental strains of aurI and aurR were constructed, and the growth curve and phenazine production of mutants were measured by fermentation. A transcriptional fusion plasmid was used to assess transcription level of promoter of phenazine synthesis gene cluster. [Results] The results of plate assays showed that aurI could produce a variety of signal molecules that could produce blue pigment in NTL4 and purple pigment in CV026. Fermentation results showed phenazine production of knock-out gene mutants were raised four times, and phenazine production of the complemental strains of aurI and aurR were reduced to the wild type level. It was found that the β-galactosidase activity fused with promoter of phenazine synthesis genes in the knock out strains were higher than that of the wild type. [Conclusion] aurI/aurR is a pair of negative regulation genes for phenazine in GP72. It could inhibit the transcription level of promoter of phenazine synthesis gene cluster, thereby affecting phenazine production.
马润亭,郭树奇,王威,张雪洪.绿针假单胞菌GP72中aurI/aurR系统调控功能[J].微生物学通报,2019,46(2):252~260
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