title: New Genes Involved in Osmotic Stress Tolerance inSaccharomyces cerevisiae.
abstract: Adaptation to changes in osmolarity is fundamental for the survival of living cells, and has implications in food and industrial biotechnology. It has been extensively studied in the yeastSaccharomyces cerevisiae, where the Hog1 stress activated protein kinase was discovered about 20 years ago. Hog1 is the core of the intracellular signaling pathway that governs the adaptive response to osmotic stress in this species. The main endpoint of this program is synthesis and intracellular retention of glycerol, as a compatible osmolyte. Despite many details of the signaling pathways and yeast responses to osmotic challenges have already been described, genome-wide approaches are contributing to refine our knowledge of yeast adaptation to hypertonic media. In this work, we used a quantitative fitness analysis approach in order to deepen our understanding of the interplay between yeast cells and the osmotic environment. Genetic requirements for proper growth under osmotic stress showed both common and specific features when hypertonic conditions were induced by either glucose or sorbitol. Tolerance to high-glucose content requires mitochondrial function, while defective protein targeting to peroxisome, GID-complex function (involved in negative regulation of gluconeogenesis), or chromatin dynamics, result in poor survival to sorbitol-induced osmotic stress. On the other side, the competitive disadvantage of yeast strains defective in the endomembrane system is relieved by hypertonic conditions. This finding points to the Golgi-endosome system as one of the main cell components negatively affected by hyperosmolarity. Most of the biological processes highlighted in this analysis had not been previously related to osmotic stress but are probably relevant in an ecological and evolutionary context.
authors.affiliation: Instituto de Ciencias de la Vid y del Vino - Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja Logroño, Spain.
authors.forename: Ramon
authors.initials: R
authors.lastname: Gonzalez
authors.affiliation: Instituto de Ciencias de la Vid y del Vino - Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja Logroño, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Morales
authors.affiliation: Instituto de Ciencias de la Vid y del Vino - Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja Logroño, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Tronchoni
authors.affiliation: Departamento de Biomedicina, Biotecnología y Salud Pública, Universidad de Cádiz Cádiz, Spain.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Cordero-Bueso
authors.affiliation: Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria-Centro di Ricerca per l'Enologia Asti, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Vaudano
authors.affiliation: Evolva Biotech A/S Copenhagen, Denmark.
authors.forename: Manuel
authors.initials: M
authors.lastname: Quirós
authors.affiliation: Departamento de Bioquímica y Biotecnología, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: Maite
authors.initials: M
authors.lastname: Novo
authors.affiliation: Instituto de Ciencias de la Vid y del Vino - Consejo Superior de Investigaciones Científicas-Universidad de La Rioja-Gobierno de La Rioja Logroño, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Torres-Pérez
authors.affiliation: Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide Sevilla, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Valero
keywords: GID-complex; Golgi-endosome; endomembrane system; mitochondrial translation; osmotic stress; peroxisome