菌株Rhodococcus sp. YL-1降解杀虫剂噻嗪酮的途径及其分子机制

作为对抗稻飞虱的主力农药之一，噻嗪酮每年被大量施用，其在水、土和食品（尤其是大米和饮用水）中的残留对生态平衡和人体健康构成威胁。在自然条件下，微生物是消除噻嗪酮残留的重要力量，微生物降解技术是解决其残留问题的理想选择，但目前相关的研究报道很少且都来自本实验室，在前期工作中我们从长期施用噻嗪酮的稻田土壤中分离到1株噻嗪酮高效降解菌Rhodococcus sp. YL-1，初步分析了其降解噻嗪酮的途径，并证明人为添加该菌株可以加快土壤中噻嗪酮残留的分解。为了更好地开发噻嗪酮残留微生物（酶）降解技术，本项目拟进一步阐明以下3个问题：①菌株YL-1降解噻嗪酮的完整途径；②关键降解酶基因；③降解酶基因的表达调控和遗传稳定性，如何通过遗传改造提高菌株降解性状的稳定性。

To control the rice planthoppers, large amount of buprofezin is used widely every year. The residues of buprofezin in soil, water and food (especially rice and drinking water) pose a threat to ecological balance and our health. Microorganisms play a very important role in the elimination of buprofezin residues in the natural conditions; microbial degradation is considered as a good method to eliminate pesticide residues. However, there are only several reports (all from our lab) about this process. Previously, in our lab, a buprofezin-degrading bacterial strain Rhodococcus sp. YL-1 was isolated from the rice field soils chronically exposed to buprofezin; a preliminary degradation pathway was identified and this strain also showed a potential in remediation of buprofezin residues. This project seeks to (1) indentify the entire metabolic pathway of buprofezin by strain YL-1; (2) clone the genes involved in the degradation of buprofezin and clarify the functions of these genes; (3) investigate the factors that affect the stability of buprofezin-degrading capability of strain YL-1. The results of this work would benefit agriculture production, food safety, and human and ecological health in buprofezin-contaminated sites.