Characterisation of Multiple Glutathione Transferases Containing the GST I Subunit with Activities toward Herbicide Substrates in Maize ( Zea mays )
✍ Scribed by Dixon, David; Cole, David J.; Edwards, Robert
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 340 KB
- Volume
- 50
- Category
- Article
- ISSN
- 1526-498X
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✦ Synopsis
The glutathione transferases (GSTs) of maize with activities toward chloroacetanilide herbicides are relatively well characterised, but their range of substrate speciÐcities has not been determined in detail. GST activities toward an extensive range of chemically diverse xenobiotic substrates, including the herbicides atrazine, alachlor, metolachlor and Ñuorodifen, have been determined in crude and puriÐed preparations from the roots and shoots of dark-grown maize seedlings treated with and without the herbicide-safener dichlormid. With the exception of the activity toward atrazine, speciÐc activities were higher in the roots than in the shoots in all cases. In untreated shoots activities were in the order atrazine \ alachlor \ metolachlor [ Ñuorodifen with safenerÈtreatment selectively increasing the activity toward the chloroacetanilides and Ñuorodifen. In the roots the highest GST activities toward herbicides were toward the chloroacetanilides. Dichlormid treatment resulted in an increase in activities toward all four herbicides in the roots of one maize cultivar (Pioneer 3394) but only enhanced the activities toward the chloroacetanilides and Ñuorodifen in cultivar Artus. Using the non-herbicide 1-chloro-2,4-dinitrobenzene (CDNB) as substrate, anion-exchange chromatography showed that the roots and shoots contained a similar range of GST isoenzymes. All of these isoenzymes were enhanced in response to safeners, though the extent of this induction was organdependent. GST isoenzymes containing the GST I subunit were puriÐed from safener-treated roots by a combination of hydrophobic interaction chromatography and affinity chromatography using Orange A agarose. Three isoenzymes could then be puriÐed following resolution by anion-exchange chromatography. The three GSTs were termed