Chemistry and metabolism of ascorbic acid in plants

Abstract

Ascorbic acid (ascorbate/AsA/vitamin C) is one of the most abundant and versatile biomolecules in plants and animals. In particular, AsA is present in high concentrations in the chloroplasts and cytosol of plant species. In plants, AsA serves as a major antioxidant and enzyme cofactor and regulates various physiological processes including stress tolerance as well as growth, development, and signal transduction. To accomplish crucial physiological roles adequately, intracellular levels of AsA in plant cells must be tightly regulated. Recent studies have revealed the pathways for AsA biosynthesis and their regulation in plants. In addition, AsA is known to be utilized as a biosynthetic precursor in the formation of several organic acids. This chapter presents up-to-date information on the metabolic processes of AsA, including biosynthesis and degradation, which influence the intracellular concentration of AsA.