title: Variability in gene content and expression of the thioredoxin system in Oenococcus oeni.
abstract: The thioredoxin system protects against oxidative stress through the reversible oxidation of the thioredoxin active center dithiol to a disulphide. The genome of Oenococcus oeni PSU-1 contains three thioredoxin genes (trxA1, trxA2, trxA3), one thioredoxin reductase (trxB) and one ferredoxin reductase (fdr) which, until recently, was annotated as a second thioredoxin reductase. For the first time, the entire thioredoxin system in several O. oeni strains isolated from wine has been analysed. Comparisons at the DNA and protein levels have been undertaken between sequences from O. oeni and other genera and species, and the genera Leuconostoc and Lactobacillus were found to present the highest similarities. The gene most frequently absent from a collection of 34 strains and the sequences annotated in the NCBI database was trxA1. Moreover, phylogenetic analysis suggested that this gene was horizontally transferred from Lactobacillus to O. oeni. Strain-dependent expression profiles were determined in rich and in wine-like media. General over-expression was detected after inoculation into wine-like medium, with trxA3 being the most highly expressed gene. The increased transcriptional levels of the thioredoxin genes are indicative of the crucial role of this system in the O. oeni response to wine harsh conditions.
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Marcel·lí Domingo, 1, 43007, Tarragona, Catalonia, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Margalef-Català
authors.affiliation: Department of Biotechnology, Università degli Studi di Verona, Verona, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Stefanelli
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Marcel·lí Domingo, 1, 43007, Tarragona, Catalonia, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Araque
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Marcel·lí Domingo, 1, 43007, Tarragona, Catalonia, Spain.
authors.forename: Karoline
authors.initials: K
authors.lastname: Wagner
authors.affiliation: Department of Biotechnology, Università degli Studi di Verona, Verona, Italy.
authors.forename: Giovanna E
authors.initials: GE
authors.lastname: Felis
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Marcel·lí Domingo, 1, 43007, Tarragona, Catalonia, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Bordons
authors.affiliation: Department of Biotechnology, Università degli Studi di Verona, Verona, Italy.
authors.forename: Sandra
authors.initials: S
authors.lastname: Torriani
authors.affiliation: Departament de Bioquímica i Biotecnologia, Facultat d'Enologia, Universitat Rovira i Virgili, Marcel·lí Domingo, 1, 43007, Tarragona, Catalonia, Spain. Electronic address: cristina.reguant@urv.cat.
authors.forename: Cristina
authors.initials: C
authors.lastname: Reguant
mesh_terms: D005285:Fermentation; D015870:Gene Expression; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D007778:Lactobacillus / Q000235:genetics; D056585:Oenococcus / Q000235:genetics*; D010084:Oxidation-Reduction; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D013879:Thioredoxins / Q000235:genetics*; D014920:Wine / Q000032:analysis
chemical_list: D013879:Thioredoxins
keywords: Malolactic fermentation; Oenococcus oeni; Stress; Thioredoxin; qPCR