Ethiprole biodegradation by Pseudomonas sp. NC1: Insights into the mechanisms and pathways

Abstract

Ethiprole is a widely used phenylpyrazole pesticide; however, microorganism-mediated degradation of ethiprole has not been reported. In this study, we isolated and identified a new and efficient strain, NC1, of Pseudomonas putida, using morphological, physiological, biochemical, and molecular methods. The strain, identified as Pseudomonas putida, utilizes ethiprole as a carbon source. We optimized the conditions for ethiprole degradation mediated by strain NC1 using the response surface method. Under optimal conditions (25 °C, pH 9, and 0.5% inoculation) we achieved a degradation rate of 79.7% within 24 h for a 50 mg/L ethiprole solution. A new ethiprole degradation pathway is proposed based on the main degradation products. The key oxidoreductase from the glucose–methanol–choline family, GmcF, involved in ethiprole degradation was identified through molecular cloning, and the degradation of other phenylimidazole insecticides by the new strain was verified using molecular docking. Additionally, we elucidated the mechanism underlying NC1 strain-mediated ethiprole degradation. We also examined the potential of the NC1 strain for the bioremediation of ethiprole-contaminated lettuce plants and soil. By optimizing this method, strain NC1 degraded 12.1% of 30 mg/L ethiprole in soil over 7 days. The half-life of ethiprole in treated lettuce plants with strain NC1 was reduced by 37.7% compared to the control group, indicating a significant effect of exogenous microorganisms on the elimination of ethiprole in lettuce plants. This study offers significant insights into the degradation pathways and mechanisms of ethiprole biodegradation and provided the basis for bioremediation of ethiprole.