Biodegradation of chlorpyrifos by soil bacteria and their effects on growth of rice seedlings under pesticide-contaminated soil

Abstract

This study identified three soil bacteria (NRRU-BW3, NRRU-BW3, and NRRU-TV11) that degrade chlor-pyrifos, produce indole-3-acetic acid, and exopolysaccharides under pesticide stress. The results revealed that soil bacteria were identified as Priestia megaterium NRRU-BW3, Bacillus siamensis NRRU-BW9, and Bacillus amylo-liquefaciens NRRU-TV11. These strains showed the ability to produce indole-3-acetic acid (IAA) and exopolysa-ccharides (EPS) in chlorpyrifos. Moreover, these bacteria can degrade chlorpyrifos (CP) in an aqueous medium, and a 33–52% degradation rate was observed after 14 days of incubation. Inoculation with the NRRU-TV11 significantly increased (P < 0.05) plant height, root length, biomass and vigour index of rice seedlings compared to uninoculated controls in chlorpyrifos-contaminated soil. The findings demonstrated the beneficial effects of indigenous NRRU--TV11 on rice seedling development and chlorpyrifos degradation and recommended this strain as a potential repla-cement for plant growth improvement and environmental bioremediation of pesticide-contaminated agricultural soils.