Section: Application Domains

Winemaking and improved strain selection

Yeasts and bacteria are essential for the winemaking process, and selection of strains based both on their efficiency and on the influence on the quality of wine is a subject of significant effort in the Aquitaine region. Unlike the species studied above, yeast and bacterial starters for winemaking cannot be genetically modified. In order to propose improved and more specialized starters, industrial producers use breeding and selection strategies.

Yeast starters from the Saccharomyces genus are used for primary, alcohol fermentation. Recent advances have made it possible to identify the genetic causes of the different technological differences between strains [55] , [54] , [53] . Manipulating the genetic causes rather than the industrial consequences is far more amenable to experimental development. An essential tool in identifying these genetic causes is comparative genomics.

Bacterial starters based on Oenococcus oeni are used in secondary, malolactic fermentation. Genetically, O. oeni presents a surprising level of intra-specific diversity, and clues that it may evolve more rapidly than expected. Studying the diversity of the emphO. oeni genomes has led to genetic tools that can be used to evaluate the predisposition of different strains to respond to oenological stresses. While identifying particular genes has been the leading strategy up to now, recently a new strategy based on comparative genomics has been undertaken to understand the impact and mechanisms of genetic diversity [20] , [23] , [21] , [32] , [36] , [28] [3] .

Starting from historical collaborations by Pascal Durrens and Elisabeth Bon with partners from the Institute for Wine and Vine Sciences in Bordeaux (ISVV), and local industry, and in the framework of an effective partnership, we apply our tools to large-scale comparative genomics of yeast and bacterial starters in winemaking.