FSY1, a horizontally transferred gene in the Saccharomyces cerevisiae EC1118 wine yeast strain, encodes a high-affinity fructose/H+ symporter.
Transport of glucose and fructose in the yeast Saccharomyces cerevisiae plays a crucial role in controlling the rate of wine fermentation. In S. cerevisiae, hexoses are transported by facilitated diffusion via hexose carriers (Hxt), which prefer glucose to fructose. However, utilization of fructose by wine yeast is critically important at the end of fermentation. Here, we report the characterization of a fructose transporter recently identified by sequencing the genome of the commercial wine yeast strain EC1118 and found in many other wine yeasts. This transporter is designated Fsy1p because of its homology with the Saccharomyces pastorianus fructose/H(+) symporter Fsy1p. A strain obtained by transformation of the V5 hxt1-7Δ mutant with FSY1 grew well on fructose, but to a much lesser extent on glucose as the sole carbon source. Sugar uptake and symport experiments showed that FSY1 encodes a proton-coupled symporter with high affinity for fructose (K(m) 0.24±0.04mM). Using real-time RT-PCR, we also investigated the expression pattern of FSY1 in EC1118 growing on various carbon sources. FSY1 was repressed by high concentrations of glucose or fructose and was highly expressed on ethanol as the sole carbon source. The characteristics of this transporter indicate that its acquisition could confer a significant advantage to S. cerevisiae during the wine fermentation process. This transporter is a good example of acquisition of a new function in yeast by horizontal gene transfer.
Galeote
Virginie
V
INRA, UMR1083, Sciences Pour l'Oenologie, 2 Place Viala, F-34060 Montpellier, France.
Novo
Maïté
M
INRA, UMR1083, Sciences Pour l'Oenologie, 2 Place Viala, F-34060 Montpellier, France.
Salema-Oom
Madalena
M
Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Superior de Ciências da Saúde Egas Moniz, 2829-511 Caparica, Portugal.|Centro de Recursos Microbiológicos (CREM), Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
Brion
Christian
C
INRA, UMR1083, Sciences Pour l'Oenologie, 2 Place Viala, F-34060 Montpellier, France.
Valério
Elisabete
E
Centro de Recursos Microbiológicos (CREM), Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
Gonçalves
Paula
P
Centro de Recursos Microbiológicos (CREM), Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
Dequin
Sylvie
S
INRA, UMR1083, Sciences Pour l'Oenologie, 2 Place Viala, F-34060 Montpellier, France.
D005285:Fermentation; D005632:Fructose / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D022761:Gene Transfer, Horizontal; D005947:Glucose / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D012441:Saccharomyces cerevisiae / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D014920:Wine / Q000032:analysis / Q000382:microbiology*
C414489:FSY1 protein, Saccharomyces pastorianus; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D005632:Fructose; D005947:Glucose