荧光假单胞杆菌2P24中gacA、dsbA和phoP/phoQ基因对小RNA因子RsmZ的转录调控  

Regulation of gacA,dsbA and phoP/phoQ genes on the transcription of small RNA Gene RsmZ in Pseudomenasfluorescens 2P24

作　　者：姜维芳[1] 吴小刚[1] 闫庆[1] 张力群[1] 

机构地区：[1]中国农业大学植物病理系,北京100193

出　　处：《微生物学报》2008年第12期1588-1594,共7页Acta Microbiologica Sinica

基　　金：国家自然科学基金(30671403);国家"863计划"(2006AA10A211);MOST-DEST国际合作项目(2007DFA31570)~~

摘　　要：Pseudomonas fluorescens 2P24是分离自麦田的植物病害生物防治菌株,产生抗生素2,4-二乙酰基间苯三酚(2,4-diacetylphloroglucinol;2,4-DAPG)是其主要防病机制。菌株2P24中小RNA基因rsmZ正调控抗生素2,4-DAPG的产量。【目的】本文研究上游调控因子对RsmZ转录表达的影响,以进一步理解抗生素产生机制。【方法】构建了rsmZ::lacZ的转录融合结构,将含有该结构的报告载体转入2P24的多个调控基因缺失突变体中,检测相应的缺失基因对rsmZ转录水平的调控作用。【结果】结果表明,反应调控因子GacA对rsmZ基因的转录具有正调控作用,二硫键合成蛋白DsbA对其负调控;双因子调控系统PhoP/PhoQ突变后,rsmZ基因的转录明显滞后。【结论】小RNA基因rsmZ在菌株2P24中受到多个基因的调控,并在信号传递网络中起到重要作用。[Objective] Pseudomonas fluorescens 2P24 is a plant disease-suppressive bacterium isolated from wheat rhizosphere. Small RNA gene rsmZ in strain 2P24 plays an important role in the production of antibiotic 2,4-diacetylphloroglucinol （2,4-DAPG）, a key factor in disease suppression. [Objective] The aim of this study was to determine the influence of upstream regulators on the transcription of rsmZ. [Methods] A reporting vector was constructed by fusing the promoter region of rsmZ gene with a promoterless lacZ gene on plasmid pRK970Km. The resulting plasmid was introduced into several regulatory gene mutants and the corresponding effects on RsmZ transcription were investigated. [Results] The results indicated that a response regulator gene gacA from GacS/GacA two-component system positively regulated the transcription of RsmZ, whereas the oxidoreductase gene dsbA negatively regulated RsmZ expression. Furthermore, mutation on PhoP/PhoQ two-component system resulted in the delay of RsmZ transcription. [Conclusion] Our study suggests that the rsrnZ gene in strain 2P24 transcripts under the pleiotropic regulation of a number of upstream genes, and may be involved in a more complex signal transduction cascade than that we have known.

关 键 词：假单胞杆菌 小RNA RsmZ 转录 

分 类 号：Q93[生物学—微生物学]