Prometryne-induced oxidative stress and impact on antioxidant enzymes in wheat

Prometryne is one of the herbicides widely used for controlling weed/grass in agricultural practice. However, whether it has an adverse effect on crops is unknown. In this study, we investigated prometryne-induced oxidative stress in wheat (Triticum aestivum). Wheat plants were grown in soils with prometryne at 0-24 mgkg(-1) soil. The growth of wheat treated with prometryne was inhibited. Chlorophyll content significantly decreased even at the low level of prometryne (4 mgkg(-1) soil). Accumulation of thiobarbituric acid reactive substances (TBARS), an indicator of cellular peroxidation, increased, suggesting oxidative damage to the plants. The prometryne-induced oxidative stress triggered significant changes in activities of a variety of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione S-transferase (GST). Activities of the enzymes showed a general increase at low prometryne concentrations but a decrease at high levels. Analysis of non-denaturing polyacrylamide gel electrophoresis (PAGE) confirmed the results. To get an insight into the molecular response, a qRT-PCR-based assay was performed to analyze the transcript abundance of Cu/Zn-SOD and GST with prometryne exposure. Our analysis revealed that both genes displayed up-regulated expression patterns similar to the activities of the two enzymes. These data imply that prometryne-induced oxidative stress was responsible for the disturbance of the growth and antioxidant defensive systems in wheat plants.