Genome-Wide Identification of Cellular Pathways and Key Genes That Respond to Sodium Bicarbonate Stress in Saccharomyces cerevisiae

Sodium bicarbonate (NaHCO(3)) is an important inorganic salt. It is not only widely used in industrial production and daily life, but is also the main stress in alkaline saline soil. NaHCO(3) has a strong ability to inhibit the growth of fungi in both natural environment and daily application. However, the mechanism by which fungi respond to NaHCO(3) stress is not fully understood. To further clarify the toxic mechanisms of NaHCO(3) stress and identify the specific cellular genes and pathways involved in NaHCO(3) resistance, we performed genome-wide screening with NaHCO(3) using a Saccharomyces cerevisiae deletion mutant library. A total of 33 deletion mutants with NaHCO(3) sensitivity were identified. Compared with wild-type strains, these mutants had significant growth defects in the medium containing NaHCO(3). Bioinformatics analysis found that the corresponding genes of these mutants are mainly enriched in the cell cycle, mitophagy, cell wall integrity, and signaling pathways. Further study using transcriptomic analysis showed that 309 upregulated and 233 downregulated genes were only responded to NaHCO(3) stress, when compared with yeast transcriptomic data under alkaline and saline stress. Upregulated genes were mainly concentrated in amino acid metabolism, steroid biosynthesis, and cell wall, while downregulated genes were enriched in various cellular metabolisms. In summary, we have identified the cellular pathways and key genes that respond to NaHCO(3) stress in the whole genome, providing resource and direction for understanding NaHCO(3) toxicity and cellular resistance mechanisms.