Anti-botrytis activity in epicuticular waxes of young grape berries of <em>Vitis vinifera</em> (Pinot noir)

The susceptibility of the grape berries against Botrytis cinerea was known as a relation with their phenological state : young grapes are resistant while mature grapes are highly sensible. In the present study, chromatographic analysis (TLC) of the epicuticular waxes of the grape berries were performed, grape berries were originated from two sensible (S792) and tolerant (T7613) cultivars of Pinot noir vineyards along their ripening to flowering from grape harvest. The epicuticular waxes of grape berries were generally composed by hydrocarbons, wax esters, free fatty acids, primary alcohols and triterpenoic acids (oleanolic acid). Changes in the epicuticular composition were shown along the maturation of grape berries, primary alcohols and oleanolic acid are predominant in the bloom stage and all constituent classes are noticed to maturity. The evidence of a substance which exhibits a strong inhibition on the conidial germination of Botrytis cinerea was made after epicuticular waxes chromatographic analysis and biological tests. This compound, characterized by a Rf (0,2) closely related to the Rf of the primary alcohols, was present in the wax extracts originated from bloom and immature grape berries stages and it was absent in the extracts issued to the mature grape berries. The concentration of the conidial germination inhibitor was markedly different between the sensible (S792) and tolerant (T7613) cultivars of Pinot vineyards. Also this antifungal product would be considereted as an hypothetical resistance marked against Botrytis cinerea