Protoplast fusion in Saccharomyces cerevisiae.

The ability of different Saccharomyces cerevisiae yeast strains to form protoplasts and protoplast fusion were studied. The protoplast formation depended mainly on strains used and the time of snail gut enzyme action. The percentages of the regenerating protoplasts varied, depending on strain, from 3 to 33 per cent. From the fusion experiments one can establish that kariogamy is prerequisite for stable for stable diploid formation. The yields of protoplast fusion were higher when both strains were rho+ as compared with rho+ and rho 0 combinations.