AUTHOR=Urrialde Verónica , Prieto Daniel , Pla Jesús , Alonso-Monge Rebeca 

TITLE=The Candida albicans Pho4 Transcription Factor Mediates Susceptibility to Stress and Influences Fitness in a Mouse Commensalism Model

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.01062

DOI=10.3389/fmicb.2016.01062

ISSN=1664-302X

ABSTRACT=<p>The Pho4 transcription factor is required for growth under low environmental phosphate concentrations in <italic>Saccharomyces cerevisiae</italic>. A characterization of <italic>Candida albicans pho4</italic> mutants revealed that these cells are more susceptible to both osmotic and oxidative stress and that this effect is diminished in the presence of 5% CO<sub>2</sub> or anaerobiosis, reflecting the relevance of oxygen metabolism in the Pho4-mediated response. A <italic>pho4</italic> mutant was as virulent as wild type strain when assayed in the <italic>Galleria mellonella</italic> infection model and was even more resistant to murine macrophages in <italic>ex vivo</italic> killing assays. The lack of Pho4 neither impairs the ability to colonize the murine gut nor alters the localization in the gastrointestinal tract. However, we found that Pho4 influenced the colonization of <italic>C. albicans</italic> in the mouse gut in competition assays; <italic>pho4</italic> mutants were unable to attain high colonization levels when inoculated simultaneously with an isogenic wild type strain. Moreover, <italic>pho4</italic> mutants displayed a reduced adherence to the intestinal mucosa in a competitive <italic>ex vivo</italic> assays with wild type cells. <italic>In vitro</italic> competitive assays also revealed defects in fitness for this mutant compared to the wild type strain. Thus, Pho4, a transcription factor involved in phosphate metabolism, is required for adaptation to stress and fitness in <italic>C. albicans</italic>.</p>