The defective gut colonization of <i>Candida albicans hog1</i> MAPK mutants is restored by overexpressing the transcriptional regulator of the white opaque transition <i>WOR1</i>

The transcriptional master regulator of the white opaque transition of <i>Candida albicans WOR1</i> is important for the adaptation to the commensal lifestyle in the mammalian gut, a major source of invasive candidiasis. We have generated cells that overproduce Wor1 in mutants defective in the Hog1 MAP kinase, defective in several stress responses and unable to colonize the mice gut. <i>WOR1</i> overexpression allows <i>hog1</i> to be established as a commensal in the murine gut in a commensalism model and even compete with wild-type <i>C. albicans</i> cells for establishment. This increased fitness correlates with an enhanced ability to adhere to biotic surfaces as well as increased proteinase and phospholipase production and a decrease in filamentation in vitro. We also show that <i>hog1</i> WOR1^OE are avirulent in a systemic candidiasis model in mice.