Gautam Pallavi, Pandey Anand Kumar, Dubey Suresh Kumar
Molecular Ecology Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
Department of Biotechnology Engineering, Institute of Engineering and Technology, Bundelkhand University, Jhansi, 284128, India.
Environ Res. 2023 Mar 15;221:115271. doi: 10.1016/j.envres.2023.115271. Epub 2023 Jan 11.
The residual imidacloprid, a widely used insecticide is causing serious environmental concerns. Knowledge of its biodegradation will help in assessing its residual mass in soil. In view of this, a soil microcosm-based study was performed to test the biodegradation potential of Agrobacterium sp. InxBP2. It achieved ∼88% degradation in 20 days and followed the pseudo-first-order kinetics (k = 0.0511 day and t=7 days). Whole genome sequencing of Agrobacterium sp. InxBP2 revealed a genome size of 5.44 Mbp with 5179 genes. Imidacloprid degrading genes at loci K7A42_07110 (ABC transporter substrate-binding protein), K7A42_07270 (amidohydrolase family protein), K7A42_07385 (ABC transporter ATP-binding protein), K7A42_16,845 (nitronate monooxygenase family protein), and K7A42_20,660 (FAD-dependent monooxygenase) having sequence and functional similarity with known counterparts were identified. Molecular docking of proteins encoded by identified genes with their respective degradation pathway intermediates exhibited significant binding energies (-6.56 to -4.14 kcal/mol). Molecular dynamic simulation discovered consistent interactions and binding depicting high stability of docked complexes. Proteome analysis revealed differential protein expression in imidacloprid treated versus untreated samples which corroborated with the in-silico findings. Further, the detection of metabolites proved the bacterial degradation of imidacloprid. Thus, results provided a mechanistic link between imidacloprid and associated degradative genes/enzymes of Agrobacterium sp. InxBP2. These findings will be of immense significance in carrying out the lifecycle analysis and formulating strategies for the bioremediation of soils contaminated with insecticides like imidacloprid.
残留的吡虫啉是一种广泛使用的杀虫剂，正引发严重的环境问题。了解其生物降解情况将有助于评估其在土壤中的残留量。鉴于此，开展了一项基于土壤微观系统的研究，以测试土壤杆菌属InxBP2的生物降解潜力。它在20天内实现了约88%的降解，并符合准一级动力学（k = 0.0511天，t = 7天）。土壤杆菌属InxBP2的全基因组测序显示，其基因组大小为5.44兆碱基对，有5179个基因。在基因座K7A42_07110（ABC转运蛋白底物结合蛋白）、K7A42_07270（酰胺水解酶家族蛋白）、K7A42_07385（ABC转运蛋白ATP结合蛋白）、K7A42_16845（亚硝酸单加氧酶家族蛋白）和K7A42_20660（FAD依赖性单加氧酶）处发现了与已知对应物具有序列和功能相似性的吡虫啉降解基因。所鉴定基因编码的蛋白质与各自降解途径中间体的分子对接显示出显著的结合能（-6.56至-4.14千卡/摩尔）。分子动力学模拟发现了一致的相互作用和结合，表明对接复合物具有高稳定性。蛋白质组分析揭示了吡虫啉处理样品与未处理样品中蛋白质表达的差异，这与计算机模拟结果相佐证。此外，代谢产物的检测证明了吡虫啉的细菌降解。因此，研究结果提供了吡虫啉与土壤杆菌属InxBP2相关降解基因/酶之间的机制联系。这些发现对于开展生命周期分析以及制定对受吡虫啉等杀虫剂污染土壤进行生物修复的策略具有极其重要的意义。
