Induction of Mating in Candida albicans by Construction of MTL a and MTL α Strains

Abstract

Although the diploid fungus Candida albicans , a human pathogen, has been thought to have no sexual cycle, it normally possesses mating-type–like orthologs ( MTL ) of both of the Saccharomyces cerevisiae mating-type genes ( MAT ) a and α. When strains containing only MTL a or MTL α were constructed by the loss of one homolog of chromosome 5, the site of the MTL loci, MTL a and MTL α strains mated, but like mating types did not. Evidence for mating included formation of stable prototrophs from strains with complementing auxotrophic markers; these contained both MTL alleles and molecular markers from both parents and were tetraploid in DNA content and mononucleate.