Oenococcus oeni: Queen of the cellar, nightmare of geneticists

Abstract

Graphical abstractThe AbstractOenococcus oeni is a wine-associated lactic acid bacterium (LAB) responsible mostly for wine malolactic fermentation (MLF). This fastidious bacterium (auxotrophic for many amino acids and slow growing) possesses remarkable adaptability to harsh physicochemical conditions and can reprogramme its metabolic pathways to enhance its survival in wine. Thus, O. oeni is an instructive bacterial model for investigating stress response mechanisms in LAB. However, the lack of appropriate techniques to modify the O. oeni genome has hampered molecular studies of this species. The application of recent advances in molecular genetics promises to provide a better understanding of the regulation of stress responses in this species in the future.

Bacterial microbiota diversity and composition in red and white wines correlate with plant-derived DNA contributions and botrytis infection

“…Grape skins have been suggested as a major source for AAB in wine, consistent with findings of reduced AAB abundance on berries washed by rain 31 . The LAB are physiologically more diverse and include Oenococcus oeni, which is typically responsible for the favourable malolactic fermentation 32 , but also Lactobacillus and Pediococcus species that can cause additional spontaneous fermentations with undesirable aromatic consequences 10,33 . The generally lower concentrations of LAB in wine, consistent in our samples, have been attributed to the mostly anaerobic lifestyles, suggesting competitive advantages for yeasts and AABs under the aerobic conditions of the grape 10 .…”

CtsR, the Master Regulator of Stress-Response in Oenococcus oeni, Is a Heat Sensor Interacting With ClpL1

“…Like most microorganisms facing stress conditions, O. oeni must adapt to survive and deciphering the molecular mechanisms involved in responding to stress is an important step to improve O. oeni MLF performance and design future malolactic starter strains. Because of its acidophilic profile and its unique genome organization, O. oeni is an intriguing and challenging model to investigate stress response mechanisms in LAB (Bartowsky, 2017; Grandvalet, 2017). Over the past decades, several genetic responses adopted by O. oeni during wine adaptation have been described, including genes involved in general stress response, membrane composition and fluidity, pH homeostasis, oxidative stress response, presence of sulfites and DNA damage (Salema et al, 1996; Guzzo et al, 1997, 1998; Jobin et al, 1997, 1999; Tourdot-Maréchal et al, 2000; Da Silveira et al, 2003; Beltramo et al, 2004; Chu-Ky et al, 2005; Coucheney et al, 2005b; Grandvalet et al, 2005, 2008; Da Silveira and Abee, 2009; Maitre et al, 2014; Darsonval et al, 2016; Margalef-Català et al, 2016).…”

Evaluating the Cytometric Detection and Enumeration of the Wine Bacterium, Oenococcus oeni

“…In many sample types, the bacteria of interest in their planktonic form are commonly found as single cells. However, there are several bacteria that also most commonly exist as doublets or chains that can impact the method used for enumeration (23)(24)(25)(26). Additionally, it is critical to understand cellular morphology that may impact the enumeration method, such as binary fission or species-specific physiological changes (27,28).…”

“…Here, we used the wine bacterium, O. oeni , which most commonly survives in doublets and can form chains greater than seven cells in length (24). O. oeni was chosen as the model species for this work to detail a thorough approach for enumerating small, chain‐forming bacteria in wine using flow cytometry.…”