禽致病性大肠杆菌clpV2基因缺失株的构建及生物学特性分析

旨在研究六型分泌系统2（type VI secretion system 2，T6SS2）clpV2基因对禽致病性大肠杆菌（avian pathogenic Escherichia coli，APEC） TW-XM菌株生物学特性的影响。本研究利用Red同源重组构建clpV2基因缺失株，将clpV2基因克隆到表达载体pBR322中，成功构建回补株。对突变株的部分生物学特性进行分析。结果显示：各突变株均能稳定遗传，且clpV2基因的缺失不影响TW-XM菌株的生长速度以及对多种抗生素的敏感性，但会导致其运动能力和生物被膜形成能力显著下降。综上表明，clpV2基因的缺失会影响TW-XM菌株的部分生物学特性，为进一步研究clpV2基因的功能和APEC的致病机制奠定基础。

Construction and Biological Characteristics Analysis of clpV2 Gene Mutant in Avian Pathogenic Escherichia coli

This study was conducted to investigate the biological characteristics of the clpV2 gene in the type VI secretion system 2 (T6SS2) from avian pathogenic Escherichia coli (APEC). The clpV2 deleted strain was constructed by the Red recombination system. In addition, the clpV2 gene was cloned into the expression vectors of pBR322 to construct the complementary strain. The mutant strains were proved to be genetically stable. Comparison of biological characteristics was performed. The data demonstrated that, the mutant strains showed no differences in growth curve and sensitivity to multiple antibiotics. But compared with the wild type strain, the motility and biofilm formation of the deleted strain were decreased significantly. This work proved that the clpV2 gene had partial impact on the biological characteristics of TW-XM. Also, this work provided further basis to investigate the function of the clpV2 gene which might also help in understanding the pathogenesis of APEC.