Candida albicans specializations for iron homeostasis: from commensalism to virulence

•The yeast C. albicans is a commensal and pathogen of humans and other mammals.•Iron and zinc are sequestered in mammalian blood and tissues but not in the gut.•C. albicans virulence requires specialized mechanisms for acquiring host iron and zinc.•Limitation of iron uptake promotes C. albicans commensalism in the gut.

Candida albicans is a fungal commensal-pathogen that persistently associates with its mammalian hosts. Between the commensal and pathogenic lifestyles, this microorganism inhabits host niches that differ markedly in the levels of bioavailable iron. A number of recent studies have exposed C. albicans specializations for acquiring iron from specific host molecules in regions where iron is scarce, while also defending against iron-related toxicity in regions where iron occurs in surfeit. Together, these results point to a central role for iron homeostasis in the evolution of this important human pathogen.