荧光假单胞菌抗生素2，4-二乙酰基间苯三酚合成的转录调控

项目名称： 荧光假单胞菌抗生素2，4-二乙酰基间苯三酚合成的转录调控

项目编号： No.30860166

项目类型： 地区科学基金项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 周洪友

作者单位： 内蒙古农业大学

项目金额： 26万元

中文摘要： 本研究是在已克隆了荧光假单胞菌2P24抗生素2,4-二乙酰基间苯三酚（2,4-Diacetylphloroglu-cinol, 2,4-DAPG）合成基因簇的基础上，利用分子遗传学手段研究该抗生素合成基因表达的转录调控因子。研究表明，通过转座子Tn5介导的随机突变方法，以含有phl-lacZ报告结构的菌株为受体，构建突变体文库，通过报告基因lacZ表达活性的变化，筛选到在转录水平上调控2,4-DAPG的调控因子PhlF、Hfq和RpoZ。通过克隆，定位突变和互补试验证明这些上游因子对2,4-DAPG 的调控功能，其中RpoZ和Hfq是对2,4-DAPG有调控功能的新基因，具有全局性调控功能。另外克隆和解析了PhlG基因，该基因对2,4- DAPG降解后生成了其合成前体MAPG。并通过生物测定说明调控因子与生防菌株防病效果之间的关系。该研究从分子水平解析抗生素合成、调控以及分泌的机制，为全面认识生防微生物生理和次生代谢调控提供一定理论基础，并为今后提高抗生素的产量和利用新的基因资源防治植物病害提供了材料.

中文关键词： 2;4-二乙酰基间苯三酚；PhlF；PhlG；RpoZ；调控

英文摘要： Based on cloned biosynthetic gene locus of antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) in Pseudomonas fluorescens strain 2P24 , molecular genetic method has been used to determine the upstream regulators that influence the transcription of 2,4-DAPG biosynthetic genes. Transposon Tn5 is employed to mutant a reporter strain of 2P24, in which the promoter region of phl gene was fused with a promoterless lacZ gene. Mutants with elevated or deduced beta-galactosidase are selected for further identification. According to the expression of reporter gene lacZ, the regulation factor of 2,4-DAPG PhlF、Hfq and RpoZ were screened in transcription level. Corresponding genes in selected mutants are cloned and in-frame deleted, and the complemented strains were constructed to elucidate their functions in Phl gene expression. RpoZ and Hfq were new genes to regulate 2,4-DAPG which had whole control function. In addition, PhlG gene was cloned and analyzed, The genes regulated 2, 4-DAPG to degrade and synthesize MAPG precursor. Pot bioassay is performed in greenhouse to understand the possible roles of these upstream regulators on the disease suppression capacity. This study provide more information on biosynthesis and regulation of bacterial secondary metabolites, and would help to increase the yield of antibiotics and use the new genetic resources for plant disease control.

英文关键词： 2;4-DAPG；hlF；PhlG；RpoZ；regulation