Diversification of glutathione transferases in plants and their role in oxidative stress defense.

Plant exposure to unfavourable environmental conditions causes stress and reduces productivity. A common consequence of stress responses, are increased levels of reactive oxygen species (ROS), which if not controlled, could eventually lead to oxidative stress, damaging lipids, proteins and DNA, and ultimately result in cell death. One of the multiple defense systems that plants employ to regulate intracellular ROS levels are glutathione transferases (GSTs). GSTs have multiple roles in mitigating oxidative stress, e.g., by detoxifying xenobiotics through conjugation with reduced glutathione (GSH) or by using GSH to reduce damaging lipid hydroperoxides. In plants, GSTs exist in particularly large families and frequently occur in tandem gene clusters. This promotes the idea of functional diversification among closely related GSTs. This review focuses on the roles of GSTs in mitigating oxidative stress in plants and mentions potential strategies for functional analysis of the importance of individual GSTs by dissecting their enzymatic activities.