This book provides an overview of antioxidants and antioxidant enzymes and their role in the mechanisms of signaling and cellular tolerance under stress in plant systems.
Major reactive oxygen species (ROS)-scavenging/modulating enzymes include the superoxide dismutase (SOD) that dismutates O₂ into H₂O₂, which is followed by the coordinated action of a set of enzymes including catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX) and peroxiredoxins (Prx) that remove H₂O2. In addition to the ROS scavenging enzymes, a number of other enzymes are found in various subcellular compartments, which are involved in maintaining such redox homeostasis either by directly scavenging particular ROS and ROS-byproducts or by replenishing antioxidants. In that respect, these enzymes can be also considered antioxidants. Such enzymes include monodehydroascorbate reductase (MDAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), alternative oxidases (AOXs), peroxidases (PODs) and glutathione S-transferases (GSTs). Some non-enzymatic antioxidants, such as ascorbic acid (vitamin C), carotenes (provitamin A), tocopherols (vitamin E), and glutathione (GSH), work in concert with antioxidant enzymes to sustain an intracellular steady-state level of ROS that promotes plant growth, development, cell cycles and hormone signaling, and reinforces the responses to abiotic and biotic environmental stressors. Offering a unique compilation of information on antioxidants and antioxidant enzymes, this is a valuable resource for advanced students and researchers working on plant biochemistry, physiology, biotechnology, and signaling in cell organelles, and those specializing in plant enzyme technology.

Plant superoxide dismutases: Function under abiotic stress conditions

Studies of catalase in plants under abiotic stress
Ascorbate peroxidase functions in higher plants: The control of the balance between oxidative damage and signaling
Glutathione reductase: Safeguarding plant cells against oxidant damage
Function of the various MDAR isoforms in higher plants
Peroxiredoxins: Types, characteristics and functions in higher plants
Redox protein thioredoxins: Function under salinity, drought and extreme temperature conditions
Biosynthesis and regulation of ascorbic acid in plants
Glutathione metabolism and its function in higher plants adapting to stress
Revisiting carotenoids and their role in plant stress responses: From biosynthesis to plant signaling mechanisms during stress. Abiotic stress response in plants - the relevance of tocopherols
Role of flavonoids in plant stress. Class III peroxidases: isoenzymes functions, localization and redox regulation.