鸭疫里默氏杆菌KYF39_09285基因缺失株的构建及生物学特性研究

Construction and Biological Characteristics of Riemerella anatipestiferΔKYF39_09285 Gene Deletion Strain

为研究KYF39_09285基因对鸭疫里默氏杆菌生物学特性及其对雏鸭致病力的影响,试验利用基因同源重组的原理构建KYF39_09285的基因缺失株RA-YMΔKYF39_09285,并使用穿梭质粒构建其基因回补菌株,评价其对鸭疫里默氏杆菌生物学特性以及雏鸭致病力的影响。结果显示:与亲本株相比,KYF39_09285基因缺失株的生长速度、生化特性、对Vero细胞的黏附入侵能力均未发生改变,但缺失株中dnaK表达量降低,对高渗、青霉素、氨苄西林、庆大霉素和链霉素的敏感性增强,对雏鸭的致病力(LD_(50))降低1.84倍,45℃胁迫下的KYF39_09285表达量显著降低。研究表明KYF39_09285与鸭疫里默氏杆菌对高温、高渗和抗生素的耐受性以及致病力有关,结果为深入研究鸭疫里默氏杆菌的致病机制奠定基础。

To study the effect of KYF39_09285 gene on the biological characteristics of Riemerella anatipestifer and its patho⁃genicity to ducklings,the gene deletion strain RA-YMΔKYF39_09285 was constructed based on homologous recombination,and its complementation strain was constructed by the transformation with shuttle plasmid,its influence on the biological characteris⁃tics of R.anatipestifer and the pathogenicity of ducklings was evaluated.Compared with the parent RA-YM strain,the growth rate,biochemical characteristics,adhesion and invasion ability to Vero cells of KYF39_09285 gene deleted strain showed no significant difference,while the expression of dnaK in the deleted strain was decreased,its sensitivity to hypertonicity,penicillin,ampicillin,gentamicin and streptomycin was increased,and its median lethal dose(LD50)to ducklings was increased by 1.84 times.It was found that the expression of KYF39_09285 was significantly reduced in KYF39_09285 gene deleted strain under 45℃.The re⁃sults showed that KYF39_09285 gene was related to the pathogenicity of R.anatipestifer and the tolerance against high tempera⁃ture,hypertonicity and antibiotics,which would provide a theoretical basis for clarify the pathogenic mechanism of R.anatipestifer.