Oenococcus oeni genomic adaptation to the wine environment
Résumé
Oenococcus oeni is a minor species among the lactic acid bacteria naturally occurring on grape fruits, but it rapidly becomes predominant in wine and is generally the only detectable species during malolactic fermentation. To identify traits responsible for this so efficient adaptation to the wine environment, we used a panel of genomic approaches to examine O. oeni at both species and infra-species levels. Strain typing methods revealed a huge diversity of strains whose genomes are shaped by recombination events and that form at least two well-defined genetic groups. Evidences for genomic plasticity and horizontal gene transfers were confirmed by genome sequence comparisons and by subtractive genomic hybridizations. Differential DNA regions specific of some strains code for enzymes that may help bacteria to cope with the harsh conditions of wine. Taken together our works support the previously suggested idea that O. oeni is a fast-evolving species and they provide the first clues about how some strains can better survive in wine. In addition they make it possible for the first time to select the best adapted strains for industrial applications on the basis of genetic traits rather than phenotypic criteria.