假单胞菌株M18 psrA突变株的构建及其对吩嗪-1-羧酸和藤黄绿菌素合成的调控  

Construction of Pseudomonas sp.M18 psrA mutant and its regulation on PCA and Plt biosynthesis

作　　者：王国昊[1] 魏雪[1] 李赛男[1] 黄显清[1] 许煜泉[1] 

机构地区：[1]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

出　　处：《微生物学通报》2012年第3期291-299,共9页Microbiology China

基　　金：国家自然科学基金项目(No.30800009);国家863计划项目(No.2007AA02Z215);国家973计划项目(No.2009CB118906)

摘　　要：【目的】假单胞菌M18是一株能同时合成吩嗪-1-羧酸(PCA)和藤黄绿菌素(Plt)两种抗生素的植物根际促生细菌。PsrA为细菌TetR家族转录调控因子。为了研究PsrA对PCA与Plt生物合成的影响,从M18菌株基因组中扩增psrA基因。【方法】通过同源重组技术,构建庆大霉素抗性片段置换psrA的突变菌株M18psrA。利用基因互补、lacZ报告基因融合分析实验,验证PsrA对抗生素合成基因的调控作用。【结果】在PPM和KMB培养基中,分别比较野生型菌株M18和突变菌株M18psrA的PCA与Plt产量,突变菌株M18psrA的PCA产量显著下降;Plt产量显著升高,为野生型菌株的10-15倍。基因互补、lacZ报告基因融合分析,进一步证明了psrA正调控PCA的phz2合成基因簇,负调控Plt的合成基因簇。【结论】PsrA区别性调控抗生素PCA与Plt的生物合成。[Objective] The rhizobacterium Pseudomonas sp. M18 can produce two antibiotics,phenazine-l-carboxylic acid （PCA） and pyoluteorin （Pit）. PsrA belongs to the TetR family bacterial transcription regulator. To investigate the effect of PsrA on the PCA and Plt biosyn- thesis, the psrA gene was amplified from M18 strain genome. [Methods] The psrA mutant （M18psrA） was constructed through gene replacement of psrA by gentamicin resistance cas- sette and homologous recombination. Gene complement experiment and lacZ gene fusion report analysis further identified whether PsrA regulates the expression of antibiotics biosynthesis gene clusters. [Results] PCA and Plt production was respectively assayed in PPM and KMB media. PCA production of psrA mutant was significantly lower than that of its parent strain M 18. However, Pit production of M 18psrA was obviously increased 10-15 times as much as that of M18 strain. Gene complement experiment and lacZ gene fusion report analysis further confirmed that PsrA strongly up-regulated PCA biosynthesis and down-regulated Plt biosynthesis. [Conclusion] PsrA regulates distinctively on the PCA and Plt biosynthesis.

关 键 词：假单胞菌株M18 psrA 吩嗪-1-羧酸 藤黄绿菌素 

分 类 号：Q936[生物学—微生物学]