De. Riechers et al., VARIABILITY OF GLUTATHIONE-S-TRANSFERASE LEVELS AND DIMETHENAMID TOLERANCE IN SAFENER-TREATED WHEAT AND WHEAT RELATIVES, Pesticide biochemistry and physiology, 56(2), 1996, pp. 88-101
Glutathione S-transferase (GST) levels were quantified in shoots of wh
eat and wheat relatives to determine if variation existed for GST leve
ls, with or without treatment with herbicide safeners, and if GST leve
ls could be used as an accurate biochemical marker for wheat seedling
tolerance to the herbicide dimethenamid. Wheat lines and relatives wer
e either unsafened or treated with the safeners fluxofenim (CGA-133205
) or cloquintocet-mexyl (CGA-185072). GST levels were assayed using an
enzyme-linked immunosorbent assay utilizing a maize GST antibody (GST
-ELISA) and an enzyme activity assay using dimethenamid as a substrate
(GST-D). In general, the GST-ELISA indicated that significant GST was
present constitutively (in untreated plants) and that the two safener
s increased GST levels to a similar extent. In contrast to the GST-ELI
SA, the GST-D assay generally detected little or no constitutive GST-D
activity; fluxofenim increased GST-D activity more than cloquintocet-
mexyl. Tolerance to dimethenamid in fluxofenim-safened wheat seedlings
in the greenhouse was correlated with GST-D activity (r(2) = 0.51) bu
t not with GST-ELISA (r(2) = 0.03). These data suggest that screening
wheat and wheat relatives for safener-increased GST-D activity can be
used as a biochemical marker to predict and select for increased wheat
seedling tolerance to dimethenamid. (C) 1996 Academic Press.