Insights into the ubiquity, persistence and microbial intervention of imidacloprid.

Imidacloprid, a neonicotinoid pesticide, is employed to increase crop productivity. Meanwhile, its indiscriminate application severely affects the non-target organisms and the environment. As an eco-friendly and economically workable option, the microbial intervention has garnered much attention. This review concisely outlines the toxicity, long-term environmental repercussions, degradation kinetics, biochemical pathways, and interplay of genes implicated in imidacloprid remediation. The studies have highlighted imidacloprid residue persistence in the environment for up to 3000 days. In view of high persistence, effective intervention is highly required. Bacteria-mediated degradation has been established as a viable approach with Bacillus spp. being among the most efficient at 30 â„ƒ and pH 7. Further, a comparative metagenomic investigation reveals dominant neonicotinoid degradation genes in agriculture compared to forest soils with distinctive microbial communities. Functional metabolism of carbohydrates, amino acids, fatty acids, and lipids demonstrated a significantly superior relative abundance in forest soil, implying its quality and fertility. The CPM, CYP4C71v2, CYP4C72, and CYP6AY3v2 genes that synthesize cyt p450 monooxygenase enzyme play a leading role in imidacloprid degradation. In the future, a systems biology approach incorporating integrated kinetics should be utilized to come up with innovative strategies for moderating the adverse effects of imidacloprid on the environment.

Repercussions of Prolonged Pesticide Use on Natural Soil Microbiome Dynamics Using Metagenomics Approach.

The residual pesticides in soil can affect the natural microbiome composition and genetic profile that drive nutrient cycling and soil fertility. In the present study, metagenomic approach was leveraged to determine modulations in nutrient cycling and microbial composition along with connected nexus of pesticide, antibiotic, and heavy metal resistance in selected crop and fallow soils having history of consistent pesticide applications. GC-MS analysis estimated residuals of chlorpyrifos, hexachlorbenzene, and dieldrin showing persistent nature of pesticides that pose selective pressure for microbial adaptation. Taxonomic profiling showed increased abundance of pesticide degrading Streptomyces, Xanthomonas, Cupriavidus, and Pseudomonas across the selected soils. Genes encoding for pesticide degrading cytochrome p450, organophosphorus hydrolase, aldehyde dehydrogenase, and oxidase were predominant and positively correlated with Bacillus, Sphingobium, and Burkholderia. Nitrogen-fixing genes (nifH, narB, and nir) were relatively less abundant in crop soils, correlating to the decrease in nitrogen-fixing bacteria (Anabaena, Pantoea, and Azotobacter). Microbial enzymes involved in carbon (pfkA, gap, pgi, and tpiA) and phosphorus cycle (gmbh and phnJ) were significantly higher in crop soils indicating extensive utilization of pesticide residuals as a nutrient source by the indigenous soil microbiota. Additionally, presence of antibiotic and heavy metal resistance genes suggested potential cross-resistance under pressure from pesticide residues. The results implied selective increase in pesticide degrading microbes with decrease in beneficial bacteria that resulted in reduced soil health and fertility. The assessment of agricultural soil microbial profile will provide a framework to develop sustainable agriculture practices to conserve soil health and fertility.

Environmental Distribution, Metabolic Fate, and Degradation Mechanism of Chlorpyrifos: Recent and Future Perspectives.

Pesticides play a significant role in crop production and have become an inevitable part of the modern environment due to their extensive distribution throughout the soil ecosystem. Prophylactic applications of chlorpyrifos (CP) affect soil fertility, modify soil microbial community structure, and pose potential health risks to the nontarget organisms. Bioremediation through microbial metabolism is found to be an ecofriendly and cheaper process for CP removal from the environment. So far, various bacterial and fungal communities have been reported for CP and its metabolites degradation. Organophosphorus hydrolase (OPH) and methyl parathion hydrolase (MPH) are crucial bacterial enzymes for CP degradation as they efficiently hydrolyze the unbreakable P-O and P = S bond. This review discusses the prospects of toxicity level, persistency, and harmful effects of CP on the environment. CP degradation mechanisms, metabolic pathways, and key enzymes, along with their structural details, are also featured. The highlights on molecular docking with OPH and MPH enzyme for CP show the best binding affinity with OPH; hence, it is an essential part of CP degradation. Simultaneously, metagenomic analysis of soil from contaminated agricultural lands and wastewater was analyzed with the goal to identify the dominant CP degraders and enzymes. The identification of potent degraders, key enzymes, and evaluation of microbial community dynamics upon pesticide exposure can be used as a warning for its dissemination and biomagnification into the food chain.