Tartaric and ascorbic acid biosynthetic pathways in plants: role of l-idonate dehydrogenase

Abstract

The present invention relates to an enzyme, L-idonate dehydrogenase, in the tartaric acid biosynthetic pathway of plants. Disclosed are novel polypeptides and polynucleotides encoding the polypeptides. The present invention further provides methods of modulating the tartaric acid and ascorbic acid levels in plants, particularly in a grapevine. The modulation of tartaric acid and ascorbic acid in plants can be used for a variety of purposes, for example, to increase or decrease the tartaric acid levels, or to increase the ascorbic acid levels in a plant. Also provided are agonists and antagonists of the enzyme for modulating tartaric acid and ascorbic acid production in plants, or extracts thereof.