mutations provide an alternative mechanism for 5-FOA resistance in .

is frequently used in the yeast community as the mutation target for 5-fluoroorotic acid (5-FOA) resistance. We identified a novel class of mutants that can grow in the presence of 5-FOA. Unlike mutants, mutants remain prototrophic and grow in the absence of uracil. In addition to 5-FOA resistance, we found that mutations to also confer resistance to 5-fluorocytosine (5-FC) and 5-fluorouracil (5-FU). In total, we identified 50 unique missense mutations across 32 residues of . We found that 28 out of the 32 affected residues are located in regions conserved between and three clinically relevant pathogenic fungi. These findings suggest that mutations to present a second target for mutation screens utilizing 5-FOA as a selection marker as well as a potential mode of resistance to the antifungal therapeutic 5-FC.