Improvement of the Champagne-Epernay-Geisenheim (CEG) Wine Yeast via Meiotic Spore Clone Selection.

Climate change is altering grape composition and ripening patterns, thereby influencing the selection criteria for wine yeast strains adapted to warmer conditions and fluctuating sugar-acid balances. Previously, we sequenced and annotated the Champagne-Epernay-Geisenheim white wine yeast CEG. CEG is a hybrid tetraploid strain with more than three genome equivalents of Saccharomyces cerevisiae and only 1/3 of a S. kudriavzevii genome. To address climate change issues, we used the limited sporulation capacity of CEG to isolate meiotic progeny. The obtained spore clones were subjected to targeted selection procedures, identifying progeny with enhanced fermentation performance under higher temperature conditions. Spore clones were also selected to carry the FOT4 allele encoding a Fungal Oligopeptide Transporter gene. We identified suitable strains, particularly GYBC 1467, that surpassed the parental strain at 25 °C with enhanced volatile aroma production. Genome sequencing of three spore clones indicated differential loss of S. kudriavzevii DNA. This approach demonstrates that, via a single round meiosis, spore clone isolates with substantially improved fermentation performance compared with the parental strain can be obtained. This provides a fast route for the generation of resilient wine yeasts capable of maintaining wine quality in increasingly difficult fermentation environments.