Key Genes and Microbial Ecological Clusters Involved in Organophosphate Ester Degradation in Agricultural Fields of a Typical Watershed in Southwest China

Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers, and they have raised global concern due to their persistence, bioaccumulation, and potential toxicity. However, OPE contamination characteristics and microbial degradation mechanisms in agricultural soils remain poorly understood. This study investigated agricultural soils from the riparian zone of the Anning River Basin in southwest China. The concentrations of 12 OPEs were determined using gas chromatography–tandem mass spectrometry. The results revealed that the total OPE concentration was moderate, with triethyl phosphate being the most abundant compound. Metagenomic techniques and Bayesian linear regression analysis were employed in combination with the Kyoto Encyclopedia of Genes and Genomes database to identify potential degradation pathways for triethyl phosphate and tris (2-chloroethyl) phosphate. The phoA, phoB, phoD, and glpQ genes, which encode phosphatases, catalyze ester bond cleavage, thereby facilitating the degradation of OPEs. Further microbial interaction network analysis identified core OPE-degrading microorganisms, including Pimelobacter simplex, Nocardioides sp. JS614, Nocardioides daphniae, and Methylocystis heyeri. Additionally, neutral community models indicated that environmental selection drives microbial community structure. In conclusion, this study provides an in-depth understanding of OPE contamination and its microbial degradation mechanisms in agricultural soils, offering theoretical insights for pollution management and remediation strategies.