title: Transcriptomic and Proteomic Analysis ofOenococcus oeniAdaptation to Wine Stress Conditions.
abstract: Oenococcus oeni, the main lactic acid bacteria responsible for malolactic fermentation in wine, has to adapt to stressful conditions, such as low pH and high ethanol content. In this study, the changes in the transcriptome and the proteome ofO. oeniPSU-1 during the adaptation period before MLF start have been studied. DNA microarrays were used for the transcriptomic analysis and two complementary proteomic techniques, 2-D DIGE and iTRAQ labeling were used to analyze the proteomic response. One of the most influenced functions in PSU-1 due to inoculation into wine-like medium (WLM) was translation, showing the over-expression of certain ribosomal genes and the corresponding proteins. Amino acid metabolism and transport was also altered and several peptidases were up regulated both at gene and protein level. Certain proteins involved in glutamine and glutamate metabolism showed an increased abundance revealing the key role of nitrogen uptake under stressful conditions. A strong transcriptional inhibition of carbohydrate metabolism related genes was observed. On the other hand, the transcriptional up-regulation of malate transport and citrate consumption was indicative of the use of L-malate and citrate associated to stress response and as an alternative energy source to sugar metabolism. Regarding the stress mechanisms, our results support the relevance of the thioredoxin and glutathione systems in the adaptation ofO. oenito wine related stress. Genes and proteins related to cell wall showed also significant changes indicating the relevance of the cell envelop as protective barrier to environmental stress. The differences found between transcriptomic and proteomic data suggested the relevance of post-transcriptional mechanisms and the complexity of the stress response inO. oeniadaptation. Further research should deepen into the metabolisms mostly altered due to wine conditions to elucidate the role of each mechanism in theO. oeniability to develop MLF.
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Margalef-Català
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Araque
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Bordons
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Reguant
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili Tarragona, Spain.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Bautista-Gallego
keywords: Oenococcus oeni; malolactic fermentation; proteomic; stress; transcriptomic; wine