XVI International Botanical Congess

Glutathione transferases (GSTs) are classified into four types in plants. Type I and type III GSTs are most abundant and are selectively induced by biotic and abiotic stress, suggesting that these proteins play a protective role. Although plant GSTs catalyse the conjugation of pesticides with glutathione, their functions in endogenous metabolism are obscure. With the assumption that type I and type III GSTs have cytoprotective activities, we have looked for evidence in a range of plants for a) GSTs catalysing the glutathione conjugation of natural products, b) GSTs selectively binding ligands which cannot undergo conjugation, c) GSTs having enzyme activities which do not involve conjugation. Evidence for GSTs functioning in these roles will be evaluated and data supporting a role for inducible type I GSTs in oxidative stress tolerance presented.