Two different Oenococcus oeni lineages are associated to either red or white wines in Burgundy: genomics and metabolomics insights

Abstract

<p style="text-align: justify;"><em>Oenococcus oeni</em> is the bacterium most often associated with spontaneous malolactic fermentation (MLF) of wine. During MLF, malic acid is transformed into lactic acid and several metabolites are modified, modulating wine’s total acidity and improving its sensory properties. Previous works have suggested that certain genetic groups of <em>O. oeni</em> strains are associated to different kinds of products. In the present study we have spotted two groups of strains isolated mainly from Burgundy wines, one associated to red wines and the other to white wines. Sequencing 14 genomes of red and white wine strains revealed that they share a common ancestor that probably colonised two different substrates –red and white wine-associated environments–, diverging over time and disseminating to various regions. Their capacity to perform MLF and modify the volatile profile of wine was determined by fermenting a chardonnay wine and analysing its volatile fraction with a non-targeted metabolomics approach by GC-MS. The strains had a different impact on the volatile composition depending on their group of origin. These results show for the first time a correspondence between the product of origin of the strains and the volatile profile of the wines they produce. Furthermore, the genetic features that might be implied in these different phenotypes are examined.</p>

Adaptation of two groups ofOenococcus oenistrains to red and white wines: the role of acidity and phenolic compounds

“…; Sternes and Borneman ; Campbell‐Sills et al . ). This includes three starters commercialized by different companies.…”

“…; Campbell‐Sills et al . ). It encodes a glucosyltransferase producing a free or cell‐bounded extracellular glucan which is known to improve the tolerance of bacteria to wine stressors, including low pH (Dols‐Lafargue et al .…”

“…Strains of the two groups have different gene repertoires, which allow them to produce different exopolysaccharides (Campbell‐Sills et al . ). Nevertheless, there is no evidence that these various compounds contribute to polyphenol resistance of the strains of AR group.…”

“…However, strains of AR‐ and AW groups are particularly interesting because they form two well‐defined genetic groups, which makes it possible to investigate their genetic characteristics (Campbell‐Sills et al . ), and most of them were isolated from Burgundy wines, suggesting that they are present together in the vineyards and in the cellars of this region and that selection of one group or the other one occurs during the production of wines. It is well known that there is a first selection of bacteria after the harvest, when they are transferred from the surface of grape berries into the grape must.…”

“…A comparative genomics analysis of these strains has revealed a close phylogenetic proximity of both groups of strains (Campbell‐Sills et al . ). It was suggested that the two groups appeared from a common ancestor that has evolved adapting to both types of wines.…”