Fabienne Larronde

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

Abstract 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 for 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 polyphenol 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.

Obtaining Vitis Vinifera cell cultures producing higher amounts of malvidin-3-O-β-glucoside

To obtain a cell line of Vitis vinifera producing mainly malvidin-3-O-β-glucoside, three methods were studied: the initiation of new cell cultures from different varieties, the modification of phytohormones in the culture media of a high anthocyanin-producing cell line, and the selection by small-aggregate cloning of new cell lines from this high producing strain. The latter technique gave a cell line accumulating a malvidin-3-O-β-glucoside proportion of 63%.