Cloning of cyp57A1 gene from Fusarium verticillioides for degradation of herbicide fomesafen

Abstract

Fomesafen is mainly used in soybean and peanut fields to control annual and perennial broad-leaved weeds with strong selectivity and good weed control effects. However, fomesafen has strong persistence and a slow degradation rate in soil. This greatly affects grain yield and the adjustment of agricultural planting structure. In this study, the fomesafen degradation gene cyp57A1 from Fusarium verticillioides, which can be stably expressed in E. coli BL21(DE3), was cloned and transformed into the engineered bacterium P. The degradation rate of fomesafen was explored via high-performance liquid chromatography technology. High-performance liquid chromatography tandem mass spectrometry (HPLC-MS) was used to separate and identify the degradation products of fomesafen in different conditions, and microbial degradation pathways of fomesafen were proposed. Response surface methodology was used to optimize the conditions of the engineered bacteria, and the optimal degradation conditions for the strains were a temperature of 37 °C, a pH of 6.0, and 5 % inoculation. The engineered bacteria successfully degraded 5–500 mg/L fomesafen, and the degradation rate was 82.65 % when the concentration of fomesafen was 100 mg/L. The degradation products were isolated and identified by HPLC-MS, and a total of 8 degradation products were obtained. It was inferred that benzene ring dechlorination, S-N bond cleavage, phenoxy group cleavage, C-N bond cleavage, nitro reduction, amino acetylation, defluorination and other pathways were involved. The excavation of engineered bacteria is highly valuable for resolving the residual fomesafen in the environment.