Etude de la diversité des souches d’Oenococcus oeni responsables de la fermentation malolactique des vins dans différentes régions vitivinicoles

Oenococcus oeni is the main species of lactic acid bacteria of oenological interest, it performs most of malolactic fermentation. O. oeni strains have often been studied to select malolactic starters. These strains have various genetic and phenotypic characteristics. However, the use of different typing methods failed so far to obtain a complete picture of the enological diversity of this species. The growing interest of winegrowers to better control the spontaneous requires a better knowledge of this diversity.The population of indigenous O. oeni strains present during MLF in different regions has been studied in an attempt to obtain a more complete picture of the diversity of the species and to know whether it would be appropriate to select strains of regions or wineries. The analysis of a large number of wines showed the presence of strains specific to wineproducing areas, different kind of wines, and wineries. SNP Genotyping allowed us to classify these strains in the already known genetic groups and confirmed the existence of specific groups to a specific kind of product. Some of these strains belonging to the same specific genetic groups showed similar behavior and technological properties. In addition to the diversity analysis, trials of production of strains and use of lees to ameliorate the MLF have been done to improve the achievement of spontaneous MLF. Taken together, these studies emphasize the high genetic diversity of the species O. oeni, the study of specific strains of type of wine could help understand the adaptation of this species to this environment.