Elucidating molecular characterization of chlorpyrifos and profenofos degrading distinct bacterial strains for enhancing seed germination potential of Gossypium arboreum L.

Abstract

Chlorpyrifos (CP) and profenofos (PF) are organophosphate pesticides (OPs) widely used in agriculture and are noxious to both fauna and flora. The presented work was designed to attenuate the toxicity of both pesticides in the growth parameters of a cotton crop by applying plant growth-promoting rhizobacteria (PGPR), namely Pseudomonas aeruginosa PM36 and Bacillus sp. PM37. The multifarious biological activities of both strains include plant growth-promoting traits, including phosphate solubilization; indole-3-acetic acid (IAA), siderophore, and HCN production; nitrogen fixation; and enzymatic activity such as cellulase, protease, amylase, and catalase. Furthermore, the molecular profiling of multi-stress-responsive genes, including acdS, ituC, czcD, nifH, and sfp, also confirmed the plant growth regulation and abiotic stress tolerance potential of PM36 and PM37. Both strains (PM36 and PM37) revealed 92% and 89% of CP degradation at 50ppm and 87% and 81% at 150ppm within 7days. Simultaneously 94% and 98% PF degradation was observed at 50ppm and 90% and 92% at 150ppm within 7days at 35°C and pH 7. Biodegradation was analyzed using HPLC and FTIR. The strains exhibited first-order reaction kinetics, indicating their reliance on CP and PF as energy and carbon sources. The presence of opd, mpd, and opdA genes in both strains also supported the CP and PF degradation potential of both strains. Inoculation of strains under normal and OP stress conditions resulted in a significant increase in seed germination, plant biomass, and chlorophyll contents of the cotton seedling. Our findings indicate that the strains PM36 and PM37 have abilities as biodegraders and plant growth promoters, with potential applications in crop sciences and bioremediation studies. These strains could serve as an environmentally friendly, sustainable, and socially acceptable solution to manage OP-contaminated sites.