RUI: Glutathione S-transferase Enzyme(s) and the Conjugation of Plant Phenolics

Many plants are known to increase the intracellular levels of phenolic compounds when they are challenged by a wide variety of stressful conditions including predation. Many phenolic compounds are toxic to a wide variety of biotic agents. In order for plants to use this defense mechanism, the species must be able to tolerate the increased level of the phenolic. Plants reduce the autotoxicity of phenolics by conjugating them to other cellular constituents. It has been recently noted that plants may conjugate some phenolics to glutathione through the action of a glutathione S-transferase. Preliminary evidence indicates that the activity of the enzyme may be regulated by phenolic levels. The objectives of this project are to: 1) characterize the glutathione S- transferase enzyme; 2) determine if plants synthesize glutathione conjugates of phenolics in vivo; and 3) determine if there is a correlation between stress and glutathione S-transferase activity. An understanding of the role of glutathione in phenolic conjugation will aid in the understanding of how plants utilize phenolics during times of stress and may provide insight into the endogenous function of plants GST enzymes.