Mass mating method in combination with G418-and aureobasidin A-resistance markers for efficient selection of hybrids from homothallic strains in Saccharomyces cerevisiae

We have developed a mass mating method using the spore suspensions of homot hallic yeasts of Saccharomyces cerevisiae in combination with dominant sele ctive drug resistance markers, Tn601(903) against geneticin and A UR1-C aga inst aureobasidin A for the selection of the hybrids. To examine the effect iveness of these markers in the mass mating method, each marker was introdu ced into a homothallic wine yeast. Using a mixed culture of spore suspensio ns from the resultant transformants, many hybrids were screened by the drug resistance markers. This method is more practical than the spore-to-spore mating method because it does not require the use of a micromanipulator and many hybrids are obtained at one time. The resultant hybrids could be util ized for industrial brewing because plasmids, which are used to confer resi stance markers, are easily eliminated from the hybrids by cultivation in a medium without drugs. We propose that the mass mating method using spore su spensions in combination with dominant selective geneticin- and aurcobasidi n A-resistance markers is useful for the selection of hybrids from industri al homothallic yeasts.