Glyphosate-Induced Increase in Glutathione S-Transferase Activity and Glutathione Content in Groundnut (Arachis hypogaea L.)

Abstract

Abstract The obvious sensitivity of most plant species to glyphosate suggests that this phosphonate is poorly metabolized in plants. The effect of glyphosate on glutathione S -transferase (GST, EC 2.5.1.18) and glutathione (GSH) levels was examined in groundnut ( Arachis hypogaea L.), in view of the adaptive significance of elevated thiol metabolism in catalyzing metabolism of several herbicides in vivo . Glyphosate treatment resulted in a significant and concentration-dependent increase in the activity of GST and GSH levels in the three groundnut cultivars, JL24, CO2, and TMV2, tested. The glyphosate-induced increase in the enzyme activity was maximum in the foliar explants of all three cultivars, but was not correlated to their sensitivity to the herbicide. Glyphosate-tolerant cell lines of groundnut ( A. hypogaea cv. JL24) selected in vitro showed an elevated basal level of GST activity and nonprotein thiol content, as opposed to the glyphosate-sensitive cell line. The glyphosate-induced increase in GST activity could be prevented by cycloheximide and actinomycin D.