Differential expression of selected Oenococcus oeni genes for adaptation in wine-like media and red wine

The differential expression of five genes related to adaptation to wine conditions in Oenococcus oeni was evaluated by studying transcriptional changes in wine-like media and in real wine during malolactic fermentation. Two strains isolated from high ethanol wine and another, less tolerant, strain were used. Expression of the selected genes (mleA, citE, hsp18, clpP and gsh) was studied by means of RT-qPCR. A higher level of gene expression was found for the more ethanol-tolerant strains, especially for citE, hsp18 and clpP. Thus, these three genes might be good markers for the more stress-resistant strains of O. oeni. In most cases, the results of expression in wine-like medium with 14 % ethanol had a similar trend to those in real wine, suggesting that the wine-like medium can be a good model for studying the stress response in O. oeni. Different expression between strains was well correlated with their ability to perform malolactic fermentation. In this way, the identified gene markers can be used in the selection of new strains as starters for malolactic fermentation.