Functional Analysis of Chlorimuron-ethyl Degrading Genes Kj-mhpC in Klebsiella jilinsis 2N3

HAO Qingkai;ZHANG Cheng;ZHANG Xianghui;PAN Hongyu;ZHANG Hao;College of Resources and Environment,Jilin Agricultural University;College of Plant Science,Jilin University,Engineering Center for Functional Research of Resource Microorganism in Jilin Province;

Klebsiella jilinsis 2N3;;chlorimuron-ethyl;;functional gene

Two hydrolase mhpC genes Kj-mhpC-2096 and Kj-mhpC-2289 in chlorimuron-ethyl degrading bacteria Klebsiella jilinsis 2 N3 were knocked out by λ-Red recombination technique,mutants of the two genes were obtained,and the knockout mutants were verified by PCR. Growth rate of the mutants and degradation of chlorimuron-ethyl were detected in the liquid basal medium with 5 mg/L chlorimuron-ethyl. Strains WT and mutants all grew to their highest concentrations at about 10 h.During the first 10 hours,ΔKj-mhpC-2096 had the slowest growth rate,the final cell concentration was the lowest,and the WT had the fastest growth rate. The degradation rate of ΔKj-mhpC-2096 andΔKj-mhpC-2289 to chlorimuron-ethyl was significantly slower than that of the WT within 8 h. After8 h,the degradation rate of ΔKj-mhpC-2289 to chlorimuron-ethyl was equivalent to that of the WT,and the final degradation rate exceeded 90%,while almost no degradation of ΔKj-mhpC-2096 was detected when the concentration of chlorimuron-ethyl dropped to 1 mg/L. These findings indicate that the deletion of Kj-mhpC weakens the degradation of chlorimuron-ethyl,which leads to the decrease of strain tolerance to chlorimuron-ethyl,and it is preliminarily proved that Kj-mhpC-2096 is involved in the degradation to chlorimuron-ethyl in Klebsiella jilinsis 2N3.