Project description:The aim of this study is to phenotype a collection of 27 S. cerevisiae commercial wine strains growing within temperatures (4-45ºC) in both minimal media (SD) and synthetic must (SM) and, taking into account µmax value, to select two strains with divergent phenotype in their capacity to grow at low temperature. To confirm this differential phenotype, we design a competition between both strains during wine fermentations. As expected, at low temperature fermentation, the strain showing a good performance out-competes to the strain growing badly in cold. Finally we aimed to decipher the molecular basis underlying this divergent phenotype by analyzing the genomic, proteomic and transcriptomic differences between both strains at low temperature (15ºC) and optimum temperature (28ºC).
Project description:To characterize the ecological interactions among S. cerevisiae strains coming from the same geographical area, we examined the fitness of two natural isolates from San Giovese grapes, alone or in competition, in synthetic wine must (SWM). We performed genome-wide analyses in order to identify the genes involved in yeast competition and cooperation.
Project description:Comparison between two commercial wine yeast strains (UCD522 and P29) differing in their production of H2S during wine fermentation.
Project description:To characterize the ecological interactions among S. cerevisiae strains coming from the same geographical area, we examined the fitness of two natural isolates from San Giovese grapes, alone or in competition, in synthetic wine must (SWM). We performed genome-wide analyses in order to identify the genes involved in yeast competition and cooperation.
Project description:Yeast mannoproteins contribute to several aspects of wine quality by protecting wine against protein haze, reducing astringency, retaining aroma compounds and stimulating growth of lactic-acid bacteria. The selection of a yeast strain simultaneously overproducing mannoproteins and showing good fermentative characteristics is a difficult task. In this work, a Saccharomyces cerevisiae x Saccharomyces cerevisiae hybrid bearing the two oenologically relevant features was constructed and a reduction in the amount of bentonite necessary for wine stabilization was observed for wines fermented with the generated strain. Additionally, different copy numbers of some genes probably related with these physiological features were detected in this hybrid. Hybrid share with parental Sc1 similar copy number of genes SPR1, SWP1, MNN10 and YPS7 related to cell wall integrity and with parental Sc2 similar copy number of some glycolytic genes as GPM1 and HXK1 as well as genes involved in hexose transport as HXT9, HXT11 and HXT12. This work demonstrates that artificial hybridization and stabilization in winemaking conditions constitute an effective approach to obtain yeast strains with desirable physiological features as mannoprotein overproducing capacity and improved fermentation performance, characteristics genetically depending on the coordinated expression of a multitude of different genes. In this work, genetically stable mannoprotein overproducing Saccharomyces cerevisiae strains simultaneously showing excellent fermentation capacities were obtained by hybridization methods giving rise to non-GMO strains. The potential relationship between the copy number of specific genes and the improved features was also evaluated by means of aCGH analysis of parental and hybrid strains.
Project description:Wine biological aging is a wine making process used to produce specific beverages in several countries in Europe, including Spain, Italy, France, and Hungary. This process involves the formation of a velum at the surface of the wine. Here, we present the first large scale comparison of all European flor strains involved in this process. We inferred the population structure of these European flor strains from their microsatellite genotype diversity and analyzed their ploidy. We show that almost all of these flor strains belong to the same cluster and are diploid, except for a few Spanish strains. Comparison of the array hybridization profile of six flor strains originating from these four countries, with that of three wine strains did not reveal any large segmental amplification. Nonetheless, some genes, including YKL221W/MCH2 and YKL222C, were amplified in the genome of four out of six flor strains. Finally, we correlated ICR1 ncRNA and FLO11 polymorphisms with flor yeast population structure, and associate the presence of wild type ICR1 and a long Flo11p with thin velum formation in a cluster of Jura strains. These results provide new insight into the diversity of flor yeast and show that combinations of different adaptive changes can lead to an increase of hydrophobicity and affect velum formation.
Project description:Comparison between two commercial wine yeast strains (UCD522 and P29) differing in their production of H2S during wine fermentation. Due to the characteristics of the strains (commercial, non-standard wine strains), the experiment was duplicated using two completely different platforms and techniques (cDNA-based and in situ synthesized oligonucleotide-based). UCD522 and P29 wine microfermentations were performed in parallel and yeast samples were taken at the stage of fastest fermentation rate. Two biological replicates per yeast strain.
Project description:In wine fermentation, the blending of non-Saccharomyces yeast with Saccharomyces cerevisiae to improve the complexity of wine has become common practice, but data regarding the impact on yeast physiology and on genetic and metabolic regulation remain limited. Here we describe a transcriptomic analysis of single species and mixed species fermentations.
