Ascorbate-glutathione cycle and abiotic stress tolerance in plants

Abstract

Plants confront fluctuating and in some cases intense environmental conditions, such as changes in irradiation, water availability, extreme temperatures, mineral nutrient accessibility, and air pollutants exposition among others. In order to face abiotic stress situations, the redox buffer capacity, mainly represented by ascorbic acid (AsA) and glutathione (GSH) pools, is involved in growth–stress responses crossroad. These compounds are associated in a set of reactions known as AsA-GSH cycle. The main function of the AsA-GSH cycle originally observed was the detoxification of reactive oxygen species (ROS) in different subcellular compartments such as chloroplast, mitochondria, or cytosol. More recently, the crucial participation of the AsA-GSH cycle in the optimization of photosynthesis was established. In addition, these antioxidants are considered essential components of cell signaling pathways triggering adaptive plant responses. The role of AsA-GSH cycle is analyzed regarding the ability of plants to overcome some selected abiotic stress situations.