The Impact of Global Change Factors on Redox Signaling Underpinning Stress Tolerance

Reduction/oxidation (redox) metabolism and associated signaling are key components of cross tolerance to biotic and abiotic stresses in plants. Climate change factors such as predicted increases in temperature and the availability of atmospheric carbon dioxide (CO2) and ozone (O-3) will have a profound effect on oxidative signaling in plants, particularly in relation to photosynthetic metabolism and environmental stress responses. Redox signaling is responsive to myriad environmental signals through influences on metabolism and the triggered activation of the suite of oxidative burst-generating enzymes, whose function is to enhance the oxidation state of the apoplast/cell wall environment. Like reactive oxygen species (ROS), the abundance of low molecular antioxidants such as ascorbate, glutathione, tocopherols and carotenoids, and antioxidant enzymes is modified by environmental triggers. Oxidants and antioxidants do not operate in isolated linear redox signaling pathways. Rather, they are part of a much larger stress signaling network that integrates information from many pathways including hormones and sugars to regulate plant growth and defense responses. Here, we explore the likely responses of oxidants and antioxidants to global change factors and discuss how they might modify gene expression, influencing overall plant fitness through altered stress responses.