title: Plasma membrane H+ and K+ transporters are involved in the weak-acid preservative response of disparate food spoilage yeasts.
abstract: The food spoilage yeasts Zygosaccharomyces bailii and Saccharomyces cerevisiae have been proposed to resist weak-acid preservative stress by different means; Z. bailii by limiting influx of preservative combined with its catabolism, S. cerevisiae by active extrusion of the preservative weak-acid anion and H(+). Measurement of H(+) extrusion by exponential-phase Z. bailii cells suggest that, in common with S. cerevisiae, this yeast uses a plasma membrane H(+)-ATPase to expel H(+) when challenged by weak-acid preservative (benzoic acid). Simultaneous measurement of Z. bailii net H(+) and K(+) fluxes showed that net K(+) influx accompanies net H(+) efflux during acute benzoic acid stress. Such ionic coupling is known for S. cerevisiae in short-term preservative stress. Both yeasts significantly accumulated K(+) on long-term exposure to benzoic acid. Analysis of S. cerevisiae K(+) transporter mutants revealed that loss of the high affinity K(+) uptake system Trk1 confers sensitivity to growth in preservative. The results suggest that cation accumulation is an important factor in adaptation to weak-acid preservatives by spoilage yeasts and that Z. bailii and S. cerevisiae share hitherto unsuspected adaptive responses at the level of plasma membrane ion transport.
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: Macpherson
authors.affiliation: Department of Agricultural Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia.
authors.forename: Lana
authors.initials: L
authors.lastname: Shabala
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors.forename: Henrietta
authors.initials: H
authors.lastname: Rooney
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors.forename: Marcus G
authors.initials: MG
authors.lastname: Jarman
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Davies
mesh_terms: D000222:Adaptation, Physiological; D000935:Antifungal Agents / Q000494:pharmacology; D019817:Benzoic Acid / Q000494:pharmacology*; D027682:Cation Transport Proteins / Q000235:genetics / Q000502:physiology; D025141:Drug Resistance, Fungal; D005520:Food Preservatives / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D011188:Potassium / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D011522:Protons; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology; D020068:Zygosaccharomyces / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*
chemical_list: D000935:Antifungal Agents; D027682:Cation Transport Proteins; D005520:Food Preservatives; D011522:Protons; D029701:Saccharomyces cerevisiae Proteins; C068664:TRK1 protein, S cerevisiae; D019817:Benzoic Acid; D006180:Proton-Translocating ATPases; D011188:Potassium