Résumé
Saccharomyces cerevisiae strains isolated from wine, rum, bread, or oak present a wide phenotypic divergence(1, 3) and different genome sequencing programs by our group (2,3) and others (4) have offered clues about the genetic diversityin this species. However, what drives the diversity of S. cerevisiae yeast strains that accomplish wine fermentation? In order tounderstand how yeast adapted to the wine environment, we built 3 x 4 recombinant populations containing either wine strains,Mediterranean oak strains (as a grape must naive population), and strains from both origins. These twelve populations were grownfor 24 serial fermentations in a typical Sauvignon grape must. Such an experimental evolution led to an improvement of the fitnessof all populations and especially from the recombinant Mediterranean oak / wine populations. Several changes in the frequenciesof allelic variations could be observed in specific regions, such as for SSU1 and ECM34 involved in sulphite resistance or MET10involved in sulphide reduction, or horizontally transferred region C involved in nitrogen uptake. This shows that adaptation to thewine environment involves multiple regions in their genome. However, adaptation to a changing environment may have a cost.When measuring H2S production of different yeast strains during alcoholic wine strains were found to be the highest producers.Interestingly, we found that this excessive production of H2S, was related to the amplification of the CUP1 genes that results fromthe adaptation to the high content of copper used for vine sanitization treatments (4). References Camarasa C et al 2011 PLoS One, 6, e25147 Coi AL et al. 2017 Mol Ecol 26, 2150-2166. Legras JL et al 2018 Mol Biol Evol, msy066 Peters et al. 2018 Nature, 556,339-344. De Guidi et al. 2023 doi: https://doi.org/10.1101/2023.11.12.566766