粘质沙雷氏菌FZSF02中转录调控因子OmpR的生物学功能

Biological Functions of Transcription Factor OmpR in Serratia marcescens FZSF02

【目的】探索EnvZ/OmpR双组分调控系统的效应蛋白OmpR对粘质沙雷氏菌FZSF02灵菌红素合成及其他生物学特性的影响。【方法】同源重组法构建ompR敲除菌株,琼脂平板产色试验和qPCR检测OmpR对菌株灵菌红素合成的影响,结晶紫染色法和琼脂平板法等研究基因敲除菌株生物被膜形成能力,运动性和对不同环境胁迫因素的耐受性。【结果】序列分析显示OmpR为序列高度保守的蛋白。PCR验证证明ompR基因敲除成功;与野生型菌株相比ΔompR失去灵菌红素合成能力,qPCR试验显示灵菌红素合成基因簇中3个关键基因pigA、pigF和pigN转录水平分别降低为野生型菌株的3.8%,2.0%和2.1%;ΔompR菌株生物被膜生成能力较野生型降低37.5%(37℃)和15.1%(27℃);OmpR对该菌的生长能力、运动能力和响应环境胁迫的能力无明显影响。【结论】ompR为一新报道的特异性调控粘质沙雷氏菌灵菌红素合成的基因,且该基因对该菌生物被膜的形成有重要影响。

【Objective】Biological functions of the regulatory protein ompR in the two component EnvZ/OmpR system,including prodigiosin-producing ability and other biological characteristics,of Serratia marcescens FZSF02 were studied.【Methods】Homologous recombination was used to construct ompR-knockout S.marcescens FZSF02.Effect of OmpR on the prodigiosin-producing ability was examined by LB agar plate incubation and qPCR.Methods of crystal violet staining,agar plate incubation,and others were applied to determine the biofilm-forming,mobility,and stress adaptation abilities of the transcription factor protein under various environmental stresses.【Results】OmpR was a protein with high conserved amino acid sequences.An ompR-deleted strain,FZSF02ΔompR,was successfully obtained by homologous recombination and confirmed by PCR.As a result,FZSF02ΔompR lost prodigiosin-producing ability that possessed by the wild strain.The transcriptional levels of pigA,pigF,and pigN of the prodigiosin biosynthesis gene cluster in FZSF02ΔompR were respectively 3.8%,2.0%and 2.1%of the wild type strain.The biofilm formation of FZSF02ΔompR declined 37.5%(at 37℃)and 15.1%(at 27℃)from its wild counterpart.On the other hand,OmpR exhibited no significant effect on the growth,mobility,or response to the environmental stress.【Conclusion】OmpR was a newly reported gene that specifically regulated the prodigiosin biosynthesis in S.marcescens.It also significantly affected the biofilm formation but not on the growth,mobility,or stress response.