Current Genetics

, Volume 58, Issue 5, pp 255–264

Potassium supply and homeostasis in the osmotolerant non-conventional yeasts Zygosaccharomyces rouxii differ from Saccharomyces cerevisiae

Authors

  • Jiří Stříbný
    • Department of Membrane TransportInstitute of Physiology Academy of Sciences of the Czech Republic
  • Olga Kinclová-Zimmermannová
    • Department of Membrane TransportInstitute of Physiology Academy of Sciences of the Czech Republic
    • Department of Membrane TransportInstitute of Physiology Academy of Sciences of the Czech Republic
Research Article

DOI: 10.1007/s00294-012-0381-7

Cite this article as:
Stříbný, J., Kinclová-Zimmermannová, O. & Sychrová, H. Curr Genet (2012) 58: 255. doi:10.1007/s00294-012-0381-7

Abstract

Three different transport systems exist to accumulate a sufficient amount of potassium cations in yeasts. The most common of these are Trk-type transporters, which are used by all yeast species. Though most yeast species employ two different types of transporters, we only identified one gene encoding a potassium uptake system (Trk-type) in the genome of the highly osmotolerant yeast Zygosaccharomyces rouxii, and our results showed that ZrTrk1 is its major (and probably only) specific potassium uptake system. When expressed in Saccharomyces cerevisiae, the product of the ZrTRK1 gene is localized to the plasma membrane and its presence efficiently complements the phenotypes of S. cerevisiae trk1trk2∆ cells. Deletion of the ZrTRK1 gene resulted in Z. rouxii cells being almost incapable of growth at low K+ concentrations and it changed some cell physiological parameters in a way that differs from S. cerevisiae. In contrast to S. cerevisiae, Z. rouxii cells without the TRK1 gene contained less potassium than the control cells and their plasma membrane was significantly hyperpolarized compared with those of the parental strain when grown in the presence of 100 mM KCl. On the other hand, subsequent potassium starvation led to a substantial depolarization which is again different from S. cerevisiae. Plasma-membrane hyperpolarization did not prevent the efflux of potassium from Z. rouxiitrk1Δ cells during potassium starvation, and the activity of ZrPma1 is less affected by the absence of ZrTRK1 than in S. cerevisiae. The use of a newly constructed Z. rouxii-specific plasmid for the expression of pHluorin showed that the intracellular pH of the Z. rouxii wild type and the trk1∆ mutant is not significantly different. Together with the fact that Z. rouxii cells contain a significantly lower amount of intracellular potassium than identically grown S. cerevisiae cells, our results suggest that this highly osmotolerant yeast species maintain its intracellular pH and potassium homeostasis in way(s) partially distinct from S. cerevisiae.

Keywords

Trk1 potassium uptake systemNon-conventional yeastsOsmotoleranceIntracellular pHPotassium homeostasispHluorinMembrane potential

Abbreviations

Ca

Candida albicans

Cd

Candida dubliniensis

Cg

Candida glabrata

Dh

Debaryomyces hansenii

Do

Debaryomyces occidentalis

Kl

Kluyveromyces lactis

Kt

Kluyveromyces thermotolerans

Ps

Pichia stipitis

Sc

Saccharomyces cerevisiae

Sk

Saccharomyces kluyveri

Sp

Schizosaccharomyces pombe

Yl

Yarrowia lipolytica

Zr

Zygosaccharomyces rouxii

Supplementary material

294_2012_381_MOESM1_ESM.pdf (46 kb)
Supplementary material 1 (PDF 46 kb)

Copyright information

© Springer-Verlag 2012