Oxidative stress promotes the development of mating projections in <i>C</i>. <i>albicans</i>.

(A) Relative ROS levels. 1 × 105 cells of strain GH1013 were spotted on YPD-K and YP-K media and cultured at 25°C for one, two, three, or five days. For each day, 1 × 106 cells were used for ROS level determination. Error bars represent standard deviation of three biological replicates. * indicates significant difference (p t test). (B) H2O2 induces the development of mating projections in the presence of glucose. 200 μL of H2O or 5 mM H2O2 solution was spread on YPD-K medium plates (90 mm). 1 × 106 cells of strain GH1350a were spotted on the medium and cultured at 25°C for three or five days. Percentages of projected cells are indicated in the corresponding images. (C) Relative expression levels of mating-related genes in response to H2O2 treatments on YPD-K medium. Error bars, standard errors of technical duplicates. *p t test. Experiment was performed in biological replicate, and a representative image is shown. (D) Efficiency of same-sex mating on YPD-K medium with or without H2O2 treatment. The mating mixtures were grown on different media at 25°C for seven days. To make YPD-K + H2O2 plates, 200 μL H2O2 (5 mM) was spread on the medium surface (of a 90-mm plate). The numerical data are presented in S3 Data. FIG1, Factor-Induced Gene 1; FUS1, cell FUSion 1; MFA1, Mating type A1; MFα, Mating α factor precursor; p, mating projection; ROS, reactive oxidative species; YPD-K, yeast extract-peptone-glucose-K2HPO4; YP-K, yeast extract-peptone-K2HPO4.