假单胞菌的RsmA家族蛋白转录后调控次生代谢的表达。菌株2P24中该家族蛋白RsmA和RsmE对大多数生防性状的调控作用相似，表现出冗余性。推测RsmA和RsmE仅在特定逆境条件下才表现出对某些次生代谢的差异调控。本研究基于上述假设设计高通量的筛选方法，筛选RsmA和RsmE差异调控下游基因的环境条件并解析作用机制。利用Biolog表型组试剂盒提供的大量培养条件，筛选到RsmA和RsmE差异调控抗生素2,4-DAPG的条件，通过分子遗传学和生化等手段阐明差异调控机制，包括RsmA和RsmE在转录和翻译水平的表达差异、与靶基因mRNA的结合位点和亲和性等，并进一步通过新的RNA组学技术（CLIP-seq）在整个转录组水平上分析RsmA和RsmE靶位点的差异。研究结果对理解细菌冗余性调控和环境适应机制有重要参考意义。

The Gac/Rsm system in bacteria is responsible for sensing and responding to environmental stimuli and regulating a wide variety of secondary metabolites. In Pseudomonas, the two component system GacS/GacA was used to regulate the transcription of a set of small RNAs, which subsequently bind to RsmA/RsmE proteins and sequester them away from their mRNA targets. RsmA and RsmE in P. fluorescens 2P24 have redundant regulatory roles on most of the known biocontrol characters, including the production of antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG). We hypothesized that RsmA and RsmE only show the different regulation of secondary metabolism under certain adverse conditions. The aim of this study is to find out the environmental conditions under which RsmA and RsmE differentially affect 2,4-DAPG production, and to reveal the regulatory mechanism of the RsmA and RsmE under these conditions. A high-throughput screening system combining the Phenotype Microarray System (Biolog Inc) with a chromogenic reporter of 2,4-DAPG biosynthesis has been established and used to screen the cultural conditions. Molecular genetic and biochemical experiments have been designed to clarify the regulatory mechanisms of RsmA and RsmE on 2,4-DAPG production, including quantification of transcriptional and translational levels of rsmA and rsmE genes, and identification of RsmA/RsmE-binding sites at 5’-UTR of 2,4-DAPG biosynthetic gene transcripts. Further analysis using a novel CLIP-seq technique will show the differences between RsmA- and RsmE-binding transcripts at the whole transcriptome level. The predicted results not only help us to understand the regulation mechanism of antibiotic production in a biocontrol Pseudomonas strain, but also provide us novel cues to understand the roles of redundant regulatory elements in the bacterial adaptive capacity upon environmental stresses.