Hgc1 Independence of Biofilm Hyphae in Candida albicans.

Biofilm and hypha formation are central to virulence of the fungal pathogen Candida albicans. The G1 cyclin gene is required for hypha formation under diverse and growth conditions. Hgc1 is required for disseminated infection and is a linchpin in the argument that hyphal morphogenesis itself is required for pathogenicity. We report here that is dispensable for hypha formation during biofilm formation both , under strong inducing conditions, and , in a mouse oropharyngeal candidiasis model. These findings are validated with two or more C. albicans isolates. Systematic screening of overexpressed cyclin genes indicates that and can compensate partially for Hgc1 function during biofilm growth. This conclusion is also supported by the severity of the Δ/Δ Δ/Δ double mutant biofilm defect. Our results suggest that hypha formation in biofilm is accomplished by combined action of multiple cyclins, not solely by Hgc1. The gene encodes a cyclin that is required for virulence of the fungal pathogen Candida albicans. It is required to produce the elongated hyphal filaments of free-living planktonic cells that are associated with virulence. Here, we show that is not required to produce hyphae in the alternative growth form of a biofilm community. We observe Hgc1-independent hyphae in two infection-relevant situations, biofilm growth and biofilm-like oropharyngeal infection. Our analysis suggests that hypha formation in the biofilm state reflects combined action of multiple cyclins.