Candida albicans diploid and tetraploid gene expression during growth on pre-spo medium

The pathogenic yeast Candida albicans displays unusual genome dynamics in which tetraploid cells, but not diploid cells, become unstable when grown on a glucose-rich 'pre-sporulation' medium. The mechanism whereby pre-spo medium induces tetraploid cell genome instability and cell death has remained poorly understood. Here, we examined gene expression of diploid and tetraploid cells during the first 24 h of growth on YPD medium at 30°C and pre-spo medium at 37°C. Despite disparate responses to growth on pre-spo medium, diploid and tetraploid cells exhibited markedly similar gene expression profiles. Genes annotated to DNA damage, DNA recombination, DNA repair, and metabolism were enriched among differentially expressed genes between YPD and pre-spo medium at 24 h. Genes annotated to metabolic processes and oxidative stress were expressed earlier during growth on pre-spo medium, indicating that cells were more metabolically active during growth on pre-spo medium and that this resulted in induction of an oxidative stress response. Overall, this project characterizes the transcriptional response of cells grown on pre-spo medium and provides insights into how pre-spo medium induces genome instability in tetraploid cells.