Figure 1.
Phylogeny of the Candida clade and the parasexual mating cycle of Candida albicans.
(A) Phylogenetic organization of the Candida clade of species and its relationship to the Saccharomyces clade. Most Candida species belong to the Candida clade, including the most frequently isolated species, C. albicans. A notable exception is the pathogen C. glabrata, which is more closely related to S. cerevisiae than to other Candida species. (B) Heterothallic and homothallic mating cycles of C. albicans. In both mating cycles cells must switch from the white state to the opaque state to become mating competent. Heterothallic mating involves fusion of diploid a and α cells to form a white tetraploid a/α cell. Under some conditions, homothallic mating can occur with between two opaque a cells (or two α cells) to form an opaque tetraploid cell.
Figure 2.
Differential response of C. albicans white and opaque cells to pheromone.
Both cell types respond to pheromone using the conserved pheromone MAP kinase cascade, but opaque cells use the Ste12/Cph1 transcription factor to turn on genes necessary for cell–cell conjugation, whereas white cells use the Tec1 transcription factor to turn on genes involved in adherence and biofilm formation. Coordination of these pathways may promote mating in vivo. Adapted from Sahni et al. [26].