Impact of Chlorpyrifos on Plant Growth Promoting Rhizobacteria Isolated from Abelmoschus esculentus

Insight into the environmental fate, hazard, detection, and sustainable degradation technologies of chlorpyrifos-an organophosphorus pesticide

Pesticides play a critical role in terms of agricultural output nowadays. On top of that, pesticides provide economic support to our farmers. However, the usage of pesticides has created a public health issue and environmental hazard. Chlorpyrifos (CPY), an organophosphate pesticide, is extensively applied as an insecticide, acaricide, and termiticide against pests in various applications. Environmental pollution has occurred because of the widespread usage of CPY, harming several ecosystems, including soil, sediment, water, air, and biogeochemical cycles. While residual levels in soil, water, vegetables, foodstuffs, and human fluids have been discovered, CPY has also been found in the sediment, soil, and water. The irrefutable pieces of evidence indicate that CPY exposure inhibits the choline esterase enzyme, which impairs the ability of the body to use choline. As a result, neurological, immunological, and psychological consequences are seen in people and the natural environment. Several research studies have been conducted worldwide to identify and develop CPY remediation approaches and its derivatives from the environment. Currently, many detoxification methods are available for pesticides, such as CPY. However, recent research has shown that the breakdown of CPY using bacteria is the most proficient, cost-effective, and sustainable. This current article aims to outline relevant research events, summarize the possible breakdown of CPY into various compounds, and discuss analytical summaries of current research findings on bacterial degradation of CPY and the potential degradation mechanism.

Ecotoxicological implications of residual pesticides to beneficial soil bacteria: A review

Optimization of crop production in recent times has become essential to fulfil food demands of constantly increasing human populations worldwide. To address this formidable challenge, application of agro-chemicals including synthetic pesticides in intensive farm practices has increased alarmingly. The excessive and indiscriminate application of pesticides to foster food production however, leads to its exorbitant deposition in soils. After accumulation in soils beyond threshold limits, pesticides harmfully affect the abundance, diversity and composition and functions of rhizosphere microbiome. Also, the cost of pesticides and emergence of resistance among insect-pests against pesticides are other reasons that require attention. Due to this, loss in soil nutrient pool cause a substantive reduction in agricultural production which warrant the search for newer environmentally friendly technology for sustainable crop production. Rhizosphere microbes, in this context, play vital roles in detoxifying the polluted environment making soil amenable for cultivation through detoxification of pollutants, rhizoremediation, bioremediation, pesticide degradation, and stress alleviation, leading to yield optimization. The response of soil microorganisms to range of chemical pesticides is variable ranging from unfavourable to the death of beneficial microbes. At cellular and biochemical levels, pesticides destruct the morphology, ultrastructure, viability/cellular permeability, and many biochemical reactions including protein profiles of soil bacteria. Several classes of pesticides also disturb the molecular interaction between crops and their symbionts impeding the overall useful biological processes. The harmful impact of pesticides on soil microbes, however, is poorly researched. In this review, the recent findings related with potential effects of synthetic pesticides on a range of soil microbiota is highlighted. Emphasis is given to find and suggest strategies to minimize the chemical pesticides usage in the real field conditions to preserve the viability of soil beneficial bacteria and soil quality for safe and sustainable crop production even in pesticide contaminated soils.

Validation and Evaluation of Plant Growth Promoting Potential of Rhizobacteria Towards Paddy Plants

This study aimed to characterize, validate, and evaluate the plant growth potential of bacterial isolates (E-2, T-2, and T-1) to determine their suitability for application as biofertilizers and/or plant-biostimulants. The plant growth-promoting potential of bacteria (E-2, T-2, and T-1) has been validated in a hydroponic study on paddy plants by inoculating bacterial isolates and monitoring the phenotypic and plant growth responses. The applicability of bacteria was tested based on their tolerance to salinity, susceptibility to antibiotics, and identification based on 16S rDNA sequencing. The isolates E-2, T-2, and T-1 improved plant growth variably and significantly (P < 0.05 at 95% confidence interval) when inoculated into the plant growth matrix, ensuring nutrient availability to the plants grown under a nutrient (nitrate or phosphate) deprived growth matrix. Isolates E-2, T-2, and T-1 grew at salt (NaCl) concentrations of 7%, 6%, and 6%, respectively, and were tolerant to saline conditions. Although these three isolates exhibited resistance to certain antibiotics, they were susceptible to a large number of readily available antibiotics. Isolates E-2, T-2, and T-1 were identified as Klebsiella sp. strain BAB-6433, Citrobacter freundii strain R2A5, and Citrobacter sp. DY1981 respectively, and all of these may be assigned to Risk-Group-2 and hence are safe in view of their susceptibility to readily available antibiotics. Hence, these isolates are promising for extensive evaluation as bioinoculants to ecologically improve soil quality, fertility, crop growth, and yield.