Isolation and characterization of mutants of Saccharomyces cerevisiae Resistant to Killer Toxin of Kluyveromyces lactis

Abstract Mutants of Saccharomyces cerevisiae resistant to the killer toxin of Kluyveromyces lactis were isolated and classified into three groups phenotypically based on the resistance of their protoplasts and their defective regeneration. These mutants were recessive and no cross-resistance of the mutants to K1 type killer toxin of S. cerevisiae was observed. The mutants were genetically assorted into seven complementation groups and all but one mutant considered to be mutations of single nuclear genes. The killer toxin bound to sensitive cells of S. cerevisiae in logarithmic phase to produce its effect.