title: Osmotic stress response in the wine yeast Dekkera bruxellensis.
abstract: Dekkera bruxellensis is mainly associated with lambic beer fermentation and wine production and may contribute in a positive or negative manner to the flavor development. This yeast is able to produce phenolic compounds, such as 4-ethylguaiacol and 4-ethylphenol which could spoil the wine, depending on their concentration. In this work we have investigated how this yeast responds when exposed to conditions causing osmotic stress, as high sorbitol or salt concentrations. We observed that osmotic stress determined the production and accumulation of intracellular glycerol, and the expression of NADH-dependent glycerol-3-phosphate dehydrogenase (GPD) activity was elevated. The involvement of the HOG MAPK pathway in response to this stress condition was also investigated. We show that in D. bruxellensis Hog1 protein is activated by phosphorylation under hyperosmotic conditions, highlighting the conserved role of HOG MAP kinase signaling pathway in the osmotic stress response. Gene Accession numbers in GenBank: DbHOG1: JX65361, DbSTL1: JX965362.
authors.affiliation: Department of Food, Environmental and Nutritional Sciences, University of Milan, Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Galafassi
authors.forename: Marco
authors.initials: M
authors.lastname: Toscano
authors.forename: Ileana
authors.initials: I
authors.lastname: Vigentini
authors.forename: Jure
authors.initials: J
authors.lastname: Piškur
authors.forename: Concetta
authors.initials: C
authors.lastname: Compagno
mesh_terms: D055167:Dekkera / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005285:Fermentation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D005993:Glycerolphosphate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009995:Osmosis; D012492:Salts / Q000378:metabolism; D013012:Sorbitol / Q000378:metabolism; D014920:Wine / Q000032:analysis / Q000382:microbiology*
chemical_list: D005656:Fungal Proteins; D012492:Salts; D013012:Sorbitol; D005993:Glycerolphosphate Dehydrogenase; D020928:Mitogen-Activated Protein Kinases; D005990:Glycerol
keywords: Dekkera bruxellensis; Glycerol; HOG MAPK; Osmotic stress; Wine yeast