Exogenous salicylic acid alleviates the toxicity of chlorpyrifos in wheat plants (Triticum aestivum)

The role of exogenous salicylic acid (SA) in protecting wheat plants (Triticum aestivum) front contamination by the insecticide chlorpyrifos was investigated in this study. The wheat plants were grown in soils with different concentrations (5, 10, 20, and 40 mg kg(-1)) of chlorpyrifos. When the third leaf emerged, the wheat leaves were sprayed with 1, 2, 4, 8, and 16 mg L-1 of SA once a day for 6 days. The results showed that wheat exposed to higher concentrations of chlorpyrifos (>= 20 mg kg 1) caused declines in growth and chlorophyll content and altered the activities of a series of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). Interestingly, treatments with different concentrations of SA mitigated the stress generated by chlorpyrifos and improved the measured parameters to varying degrees. Furthermore, a reverse transcription and quantitative PCR experiment revealed that the activities of SOD and CAT can be regulated by their target gene in wheat when treated with SA. We also found that SA is able to block the accumulation of chlorpyrifos in wheat. However, the effect of SA was related to its concentration. In this study, the application of 2 mg L-1 of SA had the greatest ameliorating effect on chlorpyrifos toxicity in wheat plants.