Genetic and environmental control of parasexual reproduction in the pathogenic Candida species

SUMMARYCandida species are major yeast pathogens that cause both mucosal candidiasis and life-threatening invasive infections. Most Candida species, including Candida albicans, have long been thought to be "imperfect" due to the lack of a complete sexual reproduction cycle. Since the discovery of the mating type-like locus in C. albicans in 1999, the regulation of (para)sexual reproduction has been intensively investigated in this organism as well as in several phylogenetically closely related species. The (para)sexual cycle is not only critical for the generation of genetic and phenotypic diversity but is also involved in the regulation of other biological processes, such as morphological transitions, biofilm development, and virulence in pathogenic fungi. In this review article, we focus on the unique characteristics and genetic and environmental regulatory mechanisms of parasexual reproduction in the pathogenic Candida species. We discuss the relationship between the white-opaque switching and mating in the Candida species, particularly in C. albicans. We describe recent findings on environmental factors, genetic regulators, and key signaling pathways involved in sexual mating in C. albicans and related species. Finally, we discuss the mating potential and associated regulatory machinery in several Candida species, where parasexual reproduction has not been observed and bring to light some open-ended questions regarding the unique features of parasexual reproduction that should be addressed in future studies in the field.