Imidacloprid degrading efficiency of Pseudomonas plecoglossicida MBSB-12 isolated from pesticide contaminated tea garden soil of Assam

Long-term use of toxic pesticides in agricultural grounds has led to adverse effects on the environment and human health. Microbe-mediated biodegradation of pollutants is considered an effective strategy for the removal of contaminants in agricultural and environmental sustainability. Imidacloprid, a neonicotinoid class of pesticides, was widely applied insecticide in the control of pests in agricultural fields including the tea gardens of Assam. Here, native bacteria from imidacloprid contaminating tea garden soils were isolated and screened for imidacloprid degradation efficiency under laboratory conditions. Out of the 30 bacterial isolates, 4 were found to tolerate high concentrations of imidacloprid (25,000 ppm), one of which isolate MBSB-12 showed the highest efficiency for imidacloprid tolerance and utilization as the sole carbon source. Morphological, biochemical, and 16 S ribosomal RNA gene sequencing-based characterization revealed the isolate as Pseudomonas plecoglossicida MBSB-12. The isolate reduced 87% of extractable imidacloprid from the treated soil in 90 days compared to the control soil (without bacterial treatment). High-Resolution Mass Spectrometry (HRMS) analysis indicated imidacloprid breakdown to comparatively less harmful products viz., imidacloprid guanidine olefin [m/z = 209.0510 (M + H)⁺], imidacloprid urea [m/z = 212.0502 (M + H)⁺] and a dechlorinated degraded product of imidacloprid with m/z value 175.0900 (M + H)⁺. Further investigation on the molecular machinery of P. plecoglossicida MBSB-12 involved in the degradation of imidacloprid is expected to provide a better understanding of the degradation pathway.