Isolation and characterization of Saccharomyces cerevisiae mutants resistant to T-2 toxin

Summary T-2 toxin, a trichothecene mycotoxin, inhibits the growth of Saccharomyces cerevisiae. We have isolated nine spontaneous S. cerevisiae mutants resistant to this toxin. The mutants were distinguished from the wild type according to their degree of resistance to T-2 toxin on media with dextrose or glycerol as the carbon source. Generation time, mutation stability and level of cross-resistance to roridin A, another trichothecene, were determined for each mutant. The T-2 toxin resistant mutants were further characterized by subsequent tests involving cross-resistance and collateral sensitivtiy to chlorampenicol, neomycin, paromomycin, ethidium bromide and thiolutin. Mutants have been placed into three subgroups and the mechanism of T-2 toxin resistance in each group has been postulated. Mutant HK1 is the first S. cerevisiae isolate resistant to roridin A. One particular isolate, mutant HK1 l , carries a single recessive nuclear mutation. This mutation was termed ttt (for T-2 toxin resistant).