Oxidative stress signalling

Abstract

Oxidative stress arises from an imbalance in the generation and removal of reac- tive oxygen species (ROS) within cells. ROS are produced during photosynthesis and respiration, as by-products of metabolism, or via dedicated enzymes. Cells are equipped with a range of efficient antioxidant mechanisms to remove ROS. Changes in the cellular redox balance result from exposure to various abiotic and biotic stresses, with induction of both ROS generation and removal mechanisms. Recent transcriptomic analyses indicate that the expression of many genes is regu- lated by ROS. These include genes encoding antioxidants, cell rescue/defence pro- teins, and signalling proteins. Genetic studies have begun to elucidate the biologi- cal roles of ROS. These include programmed cell death, stomatal closure, and gravitropism. Further work will no doubt reveal new functions for ROS as signal- ling molecules.