A novel alkali-tolerant Yarrowia lipolytica strain for dissecting Na+-coupled phosphate transport systems in yeasts

Authors

  • Renata Zvyagilskaya,

    Corresponding author
    1. Laboratory of Biological Oxidation, AN Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071, Russia
      Corresponding author. Fax: +7 095 9544088. renata_z@inbi.ras.ru
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  • Bengt L. Persson

    1. Department of Biochemistry and Biophysics, Wallenberg Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
    2. Department of Chemistry and Biomedical Sciences, Kalmar University, S-391 82 Kalmar, Sweden
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Corresponding author. Fax: +7 095 9544088. renata_z@inbi.ras.ru

Abstract

The newly isolated osmo-, salt- and alkali-tolerant Yarrowia lipolytica yeast strain is remarkable by its capacity to grow at alkaline pH values (pH 9.7), which makes it an excellent model system for studying Na+-coupled phosphate transport systems in yeast cells grown at alkaline conditions. In cells Y. lipolytica grown at pH 9.7, phosphate uptake was mediated by several kinetically discrete Na+-dependent systems that are specifically activated by Na+ ions. One of these, a low-affinity transporter, operated at high-phosphate concentrations. The other two, derepressible, high-affinity, high-capacity systems, functioned during phosphate starvation. Both H+- and Na+-coupled high-affinity phosphate transport systems of Y. lipolytica cells were under the dual control of the prevailing extracellular phosphate concentrations and pH values. The contribution of the Na+/Pi-cotransport systems into the total cellular phosphate uptake activity was progressively increased with increasing pH, reaching its maximum at pH ≥ 9.

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