College of Plant Protection, Jilin Agricultural University, Changchun 130118, PR China.
Institute of Plant Protection, Jilin Academy of Agricultural Sciences, Gongzhuling 136100, PR China.
J Hazard Mater. 2021 Jun 5;411:125112. doi: 10.1016/j.jhazmat.2021.125112. Epub 2021 Jan 14.
Degradation efficiency of Atrazine by Klebsiella variicola FH-1 is improved by the addition of Zn. Both the chromosome and plasmid genomes of strain FH-1 were sequenced and annotated to identify genes involved in the degradation of Atrazine. Four open reading frames (ORFs) 1040, 2582, 3597, and 4043 encoding Zn-dependent hydrolases were knocked out to verify their predicted functions in the degradation of Atrazine. In the presence of Zn, the biodegradation efficiency of Atrazine by knockout mutant ∆ORF 3597 was 13.7% lower than that of wild type (WT) of strain FH-1 but still 9.4% higher than that of WT without Zn. These results indicated that ORF 3597 played a synergistic role but may not be the sole factor involved in the degradation of Atrazine. The enzymatic activities of pydC encoded by ORF 3597 were further characterized in the degradation of Atrazine. Results of fluorescence staining and flow cytometry analyses showed that the survival of bacterial cells and cell membrane permeability were increased in the presence of Zn at different concentrations. Our study provided a scientific foundation for further investigation of the biological mechanisms of improving the degradation of Atrazine by strain FH-1 with the presence of Zn.
锌的添加可提高弗氏柠檬酸杆菌 FH-1 对莠去津的降解效率。对菌株 FH-1 的染色体和质粒基因组进行测序和注释，以鉴定参与莠去津降解的基因。敲除四个分别编码锌依赖水解酶的开放阅读框（ORF）1040、2582、3597 和 4043，以验证其在莠去津降解中的预测功能。在锌存在的情况下，敲除突变体 ∆ORF 3597 的莠去津生物降解效率比野生型（WT）FH-1 低 13.7%，但仍比无锌的 WT 高 9.4%。这些结果表明，ORF 3597 发挥协同作用，但可能不是参与莠去津降解的唯一因素。进一步研究了 ORF 3597 编码的 pydC 对莠去津降解的酶活性。荧光染色和流式细胞术分析结果表明，在不同浓度的锌存在下，细菌细胞的存活率和细胞膜通透性增加。本研究为进一步研究锌存在时 FH-1 菌株提高莠去津降解的生物学机制提供了科学依据。
