title: Genetic improvement of thermo-tolerance in wine Saccharomyces cerevisiae strains by a backcross approach.
abstract: During red wine fermentation, high temperatures may cause stuck fermentation by affecting the physiology of fermenting yeast. This deleterious effect is the result of the complex interaction of temperature with other physicochemical parameters of grape juice, such as sugar and lipid content. The genetic background of fermenting yeast also interacts with this complex matrix and some strains are more resistant to high temperatures than others. Here, the temperature tolerance of nine commercial starters was evaluated, demonstrating that, at high sugar concentrations, half of them are sensitive to temperature. Using a classical backcross approach, one thermo-sensitive commercial starter was genetically improved by introducing quantitative trait loci conferring resistance to temperature. With this breeding program it is possible to obtain a thermo-resistant strain sharing most of its genome with the initial commercial starter. The parental and improved strains were compared for population growth and fermentation ability in various conditions. Despite their common genetic background, these two strains showed slight physiological differences in response to environmental changes that enable identification of the key physiological parameters influencing stuck fermentation.
authors.affiliation: Université de Bordeaux, UMR OEnologie, INRA, ISVV, Villenave d'Ornon, France. philippe.marullo@u-bordeaux2.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Marullo
authors.forename: Chantal
authors.initials: C
authors.lastname: Mansour
authors.forename: Matthieu
authors.initials: M
authors.lastname: Dufour
authors.forename: Warren
authors.initials: W
authors.lastname: Albertin
authors.forename: Delphine
authors.initials: D
authors.lastname: Sicard
authors.forename: Marina
authors.initials: M
authors.lastname: Bely
authors.forename: Denis
authors.initials: D
authors.lastname: Dubourdieu
mesh_terms: D003433:Crosses, Genetic; D005285:Fermentation; D006358:Hot Temperature; D007218:Industrial Microbiology; D040641:Quantitative Trait Loci; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D013312:Stress, Physiological; D014920:Wine / Q000382:microbiology*