瓜类细菌性果斑病菌突变体文库的构建及群体感应信号分子突变株的筛选

利用三亲杂交的方法将带卡那抗性的Mini-Tn5转座子随机插入瓜类细菌性果斑病菌xjl12基因组DNA中,构建插入不同位点的突变体文库,通过信号分子高效检测菌株JZAI,筛选群体感应信号分子失活突变株。挑取2株野生株和筛选出的4株突变株,进行Southern杂交,结果表明,转座子Mini-Tn5以单拷贝随机诱变瓜类细菌性果斑病菌获得成功;对筛出的4株突变株进行了致病性和烟草过敏反应测试,发现突变株明显降低了致病性,且2株突变株(5-17,2-57)在烟草上无过敏反应。瓜类细菌性果斑病菌突变体文库的成功构建及筛选到不同突变位点的群体感应信号分子失活突变株,对从基因水平研究瓜类细菌性果斑病菌致病分子机理及群体感应相关基因奠定了基础。

Construction of Mutant Library of BFBM and Screening of Mutant of Quorum Sensing Signal Molecule

The main purpose of the study was to construct the mutant library of Bacterial Fruit Blotch of Melon and screen the related mutants of quorum sensing signal molecule.The Mini - Tn5(kmr) transposon was randomly inserted into xjl12 genomic DNA by the triparental mating to constructe multiple - site mutant library of Acidovorax avenae subsp.The four mutants of quorum sensing signal molecules inactivation were screened by AHL biosensor strain JZAI..In the Southern blot analysis for four mutants strain and two wild strains,it was found that the probe did not hybrid band to the wild strains.The results showed that the Mini - Tn5 Transposon can be single- copy random mutagenesis A.avenae Xjl12 genomic DNA.In the pathogenicity and the tobacco hypersensitive response, it was found that four mutants of the pathogenicity was obviously decreased compared with the wild strain. and two mutants didn't show hypersensitive response.Those results established the foundation for research the A. avenae pathogenic mechanism and quorum sensing relate- genes.