Genetic transformation of industrial yeasts using an amino acid analog resistance gene as a directly selectable marker.

Prototrophic and often polyploid yeasts of industrial use require some dominant genes as directly selective markers for the transformation. We examined the applicability of a dominant gene, ARO4-OFP, which causes the resistance to PFP plus tyrosine, to direct selection of the transformants from 2 laboratory and 6 industrial strains, including bakers', distillers', winery, and saké yeasts. Although the transformation rates were low and seemed different among strains, the ARO4-OFP gene was applicable to all strains tested for direct selection of the transformants.