Glutathione conjugation: atrazine detoxication mechanism in corn

Abstract

Glutathione conjugation (GS-atrazine) of the herbicide, 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) is another major detoxication mechanism in leaf tissue of corn (Zea mays, L.). The identification of GS-atrazine is the first example of glutathione conjugation as a biotransformation mechanism of a pesticide in plants. Recovery of atrazine-inhibited photosynthesis was accompanied by a rapid conversion of atrazine to GS-atrazine when the herbicide was introduced directly into leaf tissue. N-De-alkylation pathway is relatively inactive in both roots and shoots. The nonenzymatic detoxication of atrazine to hydroxyatrazine is negligible in leaf tissue. The hydroxylation pathway contributed significantly to the total detoxication of atrazine only when the herbicide was introduced into the plant through the roots. The metabolism of atrazine to GS-atrazine may be the primary factor in the resistance of corn to atrazine.