Multiple chromosomal and phenotypic changes in spontaneous mutants of Candida albicans

Previous studies have revealed the occurrence of multiple chromosomal alterations among spontaneous colony form mutants and clinical isolates of Candida albicans. In this report we show that such karyotype alterations are also seen in spontaneous and induced non-germinative mutants of the fungus. To determine if phenotypic changes other than colony form and microscopic morphology accompanied the rearrangements of the electrophoretic karyotype, we studied the following characteristics of the non-germinative and some of the colony form mutants: formation of pseudohyphae, chlamydospore production, germ tube formation, colony morphology, auxotrophy, growth at various temperatures, and colony morphology and pigment formation on selected media (bismuth sulphite and Phloxine B). We established that phenotypic and karyotypic variability among spontaneous, non-germinative mutants was no different than such variability among spontaneous colony form mutants. Thus, non-germination may represent another phenotypic consequence of genomic instability in C. albicans. The variability in different phenotypic attributes that occurred amongst the mutants was not associated with any given karyotype. Moreover, neither the low nor the high phenotypic variabilities observed were explained by the relatively high number of alterations in a limited number of chromosomes.