Role of Candida albicans mating in genetic variability and adaptation to the host

Since its discovery at the end of the XIX century, Candida albicans has emerged as one of the most important human pathogenic fungi. This yeast efficiently colonizes the gastrointestinal cavity of humans, which is an important source for gastrointestinal-mediated dissemination of the fungus to internal organs under immune suppression. Controlling colonization may therefore lead to the eradication of C. albicans which may, in turn, be a useful strategy in the prevention of candidiasis. Recent studies indicate that colonization is influenced by -and related to-the white opaque (wo) transition, an epigenetic transition that has been shown to mediate several aspects of the biology of this fungus. Efficient mating in C. albicans occurs by a two-step process which involves the conversion to a homozygous mating type cell followed by a transition to the opaque state. The discovery of the opaque cell as the mating competent phase of this fungus provided an interesting evolutionary example of the role of mating in the adaptation to a mammalian host in a pathogenic fungus. A full sexual cycle has not been observed; rather, after mating, return to a diploid state is achieved by concerted chromosome loss, being this an important source of genetic variability for this opportunistic pathogen.