Regulation of polyphenol production in Vitis vinifera cell suspension cultures by sugars

Sucrose was found to modulate polyphenol accumulation in Vitis vinifera cell cultures. The production of anthocyanins increased 12-fold after addition of 0.15 M sucrose, while that of stilbenes was only slightly affected. Sucrose did not play a physical role because metabolic sugars were required thr the induction of polyphenol accumulation. Indeed. the polyols, mannitol and sorbitol, had no effect on this accumulation. We established a model system to investigate the mechanism of sucrose regulation of poly phenol production without inhibition of grape cell growth. After addition of sucrose to the culture medium, the major sugars accumulated in grape cells were glucose and fructose, reaching 40% of the dry weight. The increase in the level of these hexoses closely coincided with the increase in anthocyanin accumulation in grape cells.