青枯雷尔氏菌TN5转座子无致病力突变株插入位点的鉴定与分析

Identification and Analysis of Tn5 Transposed Insert Sites in Avirulent Mutants of Ralstonia solanacearum

摘要: 利用TN5插入强致病力青枯雷尔氏菌FJAT-91,获得突变株FJAT-t582和FJAT-t583。菌落形态观察及弱化指数测定结果表明,突变株FJAT-t582和FJAT-t583表现为典型的无致病力菌落形态,且弱化指数均在0.8以上。利用卡那霉素抗性基因特异性引物从突变菌株FJAT-t582和FJAT-t583中均扩增出片段大小为681bp的条带,而野生型菌株FJAT-91未扩增出任何条带,说明TN5转座子已插入其基因组中。对这2株无致病力突变株进行反向PCR测序和序列比对,分析鉴定出插入位点在编码putative diguanylate phosphodiesterase基因和Ⅲ型效应蛋白基因中,推测这2个基因的突变致使强致病力菌株表现出无致病力特征。

Abstract: Mutants of Ralstonia solanacearum strain FJAT-91 using Tn5 transposon mutagenesis were developed in this paper,which were named FJAT-t582 and FJAT-t583.Colony morphology and attenuation indexes showed that both of the mutants FJAT-t582 and FJAT-t583 were avirulent and their attenuation indexes were over 0.8.A 681 bp fragment of the kanamycin resistance gene was amplified from the two genome DNA of mutants.The insertion sites were located in putative diguanylate phosphodiesterase and type Ⅲ effector protein gene respectively.And they may cause the pathogenicity reduction of the R.solanacearum.