Abstract
Flavonoids are widely distributed in the plant kingdom, and their functions as antimicrobial agents and UV-B protectants are essential for the normal growth of plants under stressful environments. Flavonoid biosynthesis is thought to proceed in the cytosolic surface of the endoplasmic reticulum, whereas many endproducts of flavonoid are accumulated in vacuoles. In the model plant Arabidopsis, intracellular flavonoid transport mechanisms are investigated for proanthocyanidin pathway, one of the flavonoid subclass being synthesized and accumulated specifically in seed coat. Some factors presumably involved in proanthocyanidin transport/accumulation, such as membrane-bound proanthocyanidin transporter TT12 and putative proanthocyanidin ligandin TT19, have so far been isolated. We describe here the results on metabolic analysis of immature seed extracts from these flavonoid mutants.
