Microcosm-omics centric investigation reveals elevated bacterial degradation of imidacloprid

Imidacloprid, a broad-spectrum insecticide, is widely used against aphids and other sucking insects. As a result, its toxic effect is becoming apparent in non-targeted organisms. In-situ bioremediation of residual insecticide from the environment utilizing efficient microbes would be helpful in reducing its load. In the present work, in-depth genomics, proteomics, bioinformatics, and metabolomics analyses were employed to reveal the potential of Sphingobacterium sp. InxBP1 for in-situ degradation of imidacloprid. The microcosm study revealed ∼79% degradation with first-order kinetics (k = 0.0726 day^-1). Genes capable of mediating oxidative degradation of imidacloprid and subsequent decarboxylation of intermediates were identified in the bacterial genome. Proteome analysis demonstrated significant overexpression of the enzymes coded by these genes. Bioinformatic analysis revealed significant affinity and binding of the identified enzymes for their respective substrates (the degradation pathway intermediates). The nitronate monooxygenase (K7A41 01745), amidohydrolase (K7A41 03835 and K7A41 07535), FAD-dependent monooxygenase (K7A41 12,275), and ABC transporter enzymes (K7A41 05325, and K7A41 05605) were found to be effective in facilitating the transport and intracellular degradation of imidacloprid. The metabolomic study identified the pathway intermediates and validated the proposed mechanism and functional role of the identified enzymes in degradation. Thus, the present investigation provides an efficient imidacloprid degrading bacterial species as evidenced by its genetic attributes which can be utilized or further improved to develop technologies for in-situ remediation.