M. Jain et N. Bhalla-sarin, Glyphosate-induced increase in glutathione S-transferase activity and glutathione content in groundnut (Arachis hypogaea L.), PEST BIOCH, 69(3), 2001, pp. 143-152
The obvious sensitivity of most plant species to glyphosate suggests that t
his phosphonate is poorly metabolized in plants. The effect of glyphosate o
n 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 s
ignificance of elevated thiol metabolism in catalyzing metabolism of severa
l herbicides in vivo. Glyphosate treatment resulted in a significant and co
ncentration-dependent increase in the activity of GST and GSH levels in the
three groundnut cultivars, JL24, CO2, and TMV2, tested. The glyphosate-ind
uced increase in the enzyme activity was maximum in the foliar explants of
all three cultivars, but was not correlated to their sensitivity to the her
bicide. Glyphosate-tolerant cell lines of groundnut (A. hypogaea cv. JL24)
selected in vitro showed an elevated basal level of GST activity and nonpro
tein thiol content, as opposed to the glyphosate-sensitive cell line. The g
lyphosate-induced increase in GST activity could be prevented by cyclohexim
ide and actinomycin D. (C) 2001 Academic Press.