瓜类细菌性果斑病菌luxR基因的功能分析

摘要

luxR基因作为信号分子受体蛋白的编码基因,在革兰氏阴性菌群体感应(quorum sensing,QS)LuxI/LuxR环路中起重要作用.本研究采用PCR技术从瓜类细菌性果斑病菌(Acidovgorax avenae subsp.citrulli)xjL12中扩增出luxR同源基因,应用同源重组的方法构建了突变株(△luxR),并对其功能进行初步研究.实验结果表明,△luxR与野生型菌株相比产生的群体感应信号分子浓度降低,抗生素耐受水平有所提高,对哈密瓜(Cucuumis melo var.cantalupensis))幼苗的致病能力下降;RT-PCR实验表明,luxR基因的缺失对luxI基因的表达有抑制作用.本研究为今后对以luxR基因为靶标,利用信号干扰技术综合防治瓜类细菌性果斑病提供基础资料.%LuxR homologues are the main component of LuxI/LuxR circus in quorum sensing (QS) of Gram negative bacteria. In this study, an internal fragment of luxR homologue from A cidovorax avenae subsp.citrulli was amplified by PCR, the luxR insertion mutant was constructed by homologue recombination. In comparison with the wild-type strain, the luxR deletion mutant (ΔluxR) had a significantly reduced ability to form acyl homoserine lactones (AHLs), which are quorum-sensing molecules. Tolerance to antibiotics were enhanced in the ΔluxR than that of the wild-type strain. ΔluxR had reduced virulence on melon (Cucuumis melo var. cantalupensis) leaves.RT-PCR indicated that LuxR protein regulated expression of the luxl gene. The study of luxR gene is to provide basic data for the prevention and control of Acidovorax avenae subsp. citrulli using the technology of signal interference.