Gene Disruption by Homologous Recombination in the Xylella fastidiosa Citrus Variegated Chlorosis Strain

Mutagenesis by homologous recombination was evaluated in Xylella fastidiosa by using the bga gene, coding for β-galactosidase, as a model. Integration of replicative plasmids by homologous recombination between the cloned truncated copy of bga and the endogenous gene was produced by one or two crossover events leading to β-galactosidase mutants. A promoterless chloramphenicol acetyltransferase gene was used to monitor the expression of the target gene and to select a cvaB mutant.

本研究以编码β-半乳糖苷酶（β-galactosidase）的bga基因为模式基因，对嗜木质棒杆菌（Xylella fastidiosa）内的同源重组诱变效应开展评估。复制型质粒通过克隆获得的截短型bga拷贝与内源bga基因之间的同源重组实现整合，该整合过程由单次或两次交叉互换事件介导，最终得到β-半乳糖苷酶突变体。本研究采用无启动子的氯霉素乙酰转移酶（chloramphenicol acetyltransferase）基因，用于监测靶基因的表达，并筛选获得cvaB突变体。