Saccharomyces species, which are mostly used in the food and beverage industries, are known to differ in their fermentation efficiency and tolerance of adverse fermentation conditions. However, the basis of their difference has not been fully elucidated, although their genomes have been sequenced and analyzed. Five strains of four Saccharomyces species (S. cerevisiae, S. kudriavzevii, S. bayanus, and S. paradoxus), when grown in parallel in laboratory conditions, exhibit very similar basic physiological parameters such as membrane potential, intracellular pH, and the degree to which they are able to quickly activate their Pma1 H+-ATPase upon glucose addition. On the other hand, they differ in their ability to proliferate in media with a very low concentration of potassium, in their osmotolerance and tolerance to toxic cations and cationic drugs in a growth-medium specific manner, and in their capacity to survive anhydrobiosis. Overall, S. cerevisiae (T73 more than FL100) and S. paradoxus are the most robust, and S. kudriavzevii the most sensitive species. Our results suggest that the difference in stress survival is based on their ability to quickly accommodate their cell size and metabolism to changing environmental conditions and to adjust their portfolio of available detoxifying transporters.

• Keywords
• Intracellular pH, Membrane potential, Saccharomyces, Stress tolerance,
• MeSH
• Fermentation MeSH
• Fungal Proteins genetics   metabolism   MeSH
• Stress, Physiological MeSH
• Glucose metabolism   MeSH
• Proton-Translocating ATPases genetics   metabolism   MeSH
• Saccharomyces classification   genetics   growth & development   physiology   MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH
• Names of Substances
• Fungal Proteins MeSH
• Glucose MeSH
• Proton-Translocating ATPases MeSH

The maintenance of potassium homeostasis is crucial for all types of cells, including Candida glabrata. Three types of plasma-membrane systems mediating potassium influx with different transport mechanisms have been described in yeasts: the Trk1 uniporter, the Hak cation-proton symporter and the Acu ATPase. The C. glabrata genome contains only one gene encoding putative system for potassium uptake, the Trk1 uniporter. Therefore, its importance in maintaining adequate levels of intracellular potassium appears to be critical for C. glabrata cells. In this study, we first confirmed the potassium-uptake activity of the identified gene's product by heterologous expression in a suitable S. cerevisiae mutant, further we generated a corresponding deletion mutant in C. glabrata and analysed its phenotype in detail. The obtained results show a pleiotropic effect on the cell physiology when CgTRK1 is deleted, affecting not only the ability of trk1Δ to grow at low potassium concentrations, but also the tolerance to toxic alkali-metal cations and cationic drugs, as well as the membrane potential and intracellular pH. Taken together, our results find the sole potassium uptake system in C. glabrata cells to be a promising target in the search for its specific inhibitors and in developing new antifungal drugs.

• MeSH
• Cell Membrane metabolism   MeSH
• Candida glabrata metabolism   physiology   MeSH
• Potassium metabolism   MeSH
• Homeostasis physiology   MeSH
• Ion Transport physiology   MeSH
• Cations metabolism   MeSH
• Membrane Potentials physiology   MeSH
• Cation Transport Proteins metabolism   MeSH
• Gene Expression Regulation, Fungal physiology   MeSH
• Saccharomyces cerevisiae metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Potassium MeSH
• Cations MeSH
• Cation Transport Proteins MeSH
• Trk1 protein, Candida albicans MeSH Browser