Trifluoroleucine resistance as a dominant molecular marker in transformation of strains of Saccharomyces cerevisiae isolated from wine.

The resistance to 5,5,5-trifluoro-DL-leucine, encoded by the dominant allele LEU4-1, was used as a selectable marker to transform laboratory and natural Saccharomyces cerevisiae strains by the lithium acetate procedure. Results of transformation of S. cerevisiae laboratory and wine natural strains showed that trifluoroleucine resistance is a very effective selection marker and can be widely used to transform prototrophic S. cerevisiae strains. The LEU4-1 gene could also be exploited to improve wine flavour, as indicated by the higher isoamyl alcohol content of the transformants compared to the parental strains.