Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Basic Medical College, Shenyang Medical College, Shenyang 100034, China.
Int J Mol Sci. 2022 Aug 31;23(17):9890. doi: 10.3390/ijms23179890.
Chlorimuron-ethyl is a widely used herbicide in agriculture. However, uncontrolled chlorimuron-ethyl application causes serious environmental problems. Chlorimuron-ethyl can be effectively degraded by microbes, but the underlying molecular mechanisms are not fully understood. In this study, we identified the possible pathways and key genes involved in chlorimuron-ethyl degradation by the strain CHL1, a Methylocystaceae strain with the ability to degrade sulfonylurea herbicides. Using a metabolomics method, eight intermediate degradation products were identified, and three pathways, including a novel pyrimidine-ring-opening pathway, were found to be involved in chlorimuron-ethyl degradation by strain CHL1. Transcriptome sequencing indicated that three genes (, , and ) are involved in chlorimuron-ethyl degradation by strain CHL1. The gene knock-out and complementation techniques allowed for the functions of the three genes to be identified, and the enzymes involved in the different steps of chlorimuron-ethyl degradation pathways were preliminary predicted. The results reveal a previously unreported pathway and the key genes of chlorimuron-ethyl degradation by strain CHL1, which have implications for attempts to enrich the biodegradation mechanism of sulfonylurea herbicides and to construct engineered bacteria in order to remove sulfonylurea herbicide residues from environmental media.
氯嘧磺隆乙基是农业中广泛使用的除草剂。然而，氯嘧磺隆乙基的无控制应用会导致严重的环境问题。氯嘧磺隆乙基可以被微生物有效降解，但潜在的分子机制尚不完全清楚。在这项研究中，我们通过具有降解磺酰脲类除草剂能力的甲基球菌科菌株 CHL1 鉴定了氯嘧磺隆乙基降解可能涉及的途径和关键基因。使用代谢组学方法，鉴定了 8 个中间降解产物，发现菌株 CHL1 参与氯嘧磺隆乙基降解的途径包括一个新的嘧啶环开裂途径。转录组测序表明，菌株 CHL1 中有三个基因（、和）参与氯嘧磺隆乙基的降解。基因敲除和互补技术鉴定了这三个基因的功能，并初步预测了氯嘧磺隆乙基降解途径不同步骤中涉及的酶。结果揭示了菌株 CHL1 降解氯嘧磺隆乙基的一条以前未报道的途径和关键基因，这对于丰富磺酰脲类除草剂的生物降解机制以及构建用于从环境介质中去除磺酰脲类除草剂残留的工程菌具有重要意义。
