Copper-based grape pest management has impacted wine aroma.

Despite the high energetic cost of the reduction of sulfate to H(2)S, required for the synthesis of sulfur-containing amino acids, some wine Saccharomyces cerevisiae strains have been reported to produce excessive amounts of H(2)S during alcoholic fermentation, which is detrimental to wine quality. Surprisingly, in the presence of sulfite, used as a preservative, wine strains produce more H(2)S than wild (oak) or wine velum (flor) isolates during fermentation. Since copper resistance caused by the amplification of the sulfur rich protein Cup1p is a specific adaptation trait of wine strains, we analyzed the link between copper resistance mechanism, sulfur metabolism and H(2)S production. We show that a higher content of copper in the must increases the production of H(2)S, and that SO(2) increases the resistance to copper. Using a set of 51 strains we observed a positive and then negative relation between the number of copies of CUP1 and H(2)S production during fermentation. This complex pattern could be mimicked using a multicopy plasmid carrying CUP1, confirming the relation between copper resistance and H(2)S production. The massive use of copper for vine sanitary management has led to the selection of resistant strains at the cost of a metabolic tradeoff: the overproduction of H(2)S, resulting in a decrease in wine quality.