ABSTRACTPathogenic fungi are capable of switching between different phenotypes, each of which has a different biological advantage. In the most prevalent human fungal pathogen,Candida albicans, phenotypic transitions not only improve its adaptation to a continuously changing host microenvironment but also regulate sexual mating. In this report, we show thatCandida tropicalis, another important human opportunistic pathogen, undergoes reversible and heritable phenotypic switching, referred to as the “white-opaque” transition. Here we show thatN-acetylglucosamine (GlcNAc), an inducer of white-to-opaque switching inC. albicans, promotes opaque-cell formation and mating and also inhibits filamentation in a number of naturalC. tropicalisstrains. Our results suggest that host chemical signals may facilitate this phenotypic switching and mating ofC. tropicalis, which had been previously thought to reproduce asexually. Overexpression of theC. tropicalis WOR1gene inC. albicansinduces opaque-cell formation. Additionally, an intermediate phase between white and opaque was observed inC. tropicalis, indicating that the switching could be tristable.
MTL–Independent Phenotypic Switching in Candida tropicalis and a Dual Role for Wor1 in Regulating Switching and Filamentation
