DICTYOSTELIUM CAVEATUM MUTANTS SELECTED FOR A NYSTATIN-RESISTANT PHENOTYPE ARE CROSS-RESISTANT TO PISATIN AND OTHER ISOFLAVONOID PHYTOALEXINS

Cellular slime mould amoebae can be induced to become resistant to an otherwise inhibitory concentration of pisatin, an isoflavonoid phytoal exin of pea, if they are first treated with a subinhibitory concentrat ion. We report here the serendipitous isolation of pisatin-resistant m utants in the cellular slime mould Dictyostelium caveatum. However, th e pisatin resistance phenotype of the mutants appears to have a differ ent basis than the inducible pisatin resistance phenotype of the wild type.