THE FUNCTIONS AND REGULATION OF GLUTATHIONE S-TRANSFERASES IN PLANTS

Glutathione S-transferases (GSTs) play roles in both normal cellular m etabolism as well as in the detoxification of a wide variety of xenobi otic compounds, and they have been intensively studied with regard to herbicide detoxification in plants. A newly discovered plant GST subcl ass has been implicated in numerous stress responses, including those arising from pathogen attack, oxidative stress, and heavy-metal toxici ty. In addition, plant GSTs play a role in the cellular response to au xins and during the normal metabolism of plant secondary products like anthocyanins and cinnamic acid. This review presents the current know ledge about the functions of GSTs in regard to both herbicides and end ogenous substrates. The catalytic mechanism of GST activity as well as the fate of glutathione S-conjugates are reviewed. Finally, a summary of what is known about the gene structure and regulation of plant GST s is presented.