title: The spxB gene as a target to identify Lactobacillus casei group species in cheese.
abstract: This study focused on the spxB gene, which encodes for pyruvate oxidase. The presence of spxB in the genome and its transcription could be a way to produce energy and allow bacterial growth during carbohydrate starvation. In addition, the activity of pyruvate oxidase, which produces hydrogen peroxide, could be a mechanism for interspecies competition. Because this gene seems to provide advantages for the encoding species for adaptation in complex ecosystems, we studied spxB in a large set of cheese isolates belonging to the Lactobacillus casei group. Through this study, we demonstrated that this gene is widely found in the genomes of members of the L. casei group and shows variability useful for taxonomic studies. In particular, the HRM analysis method allowed for a specific discrimination between Lactobacillus rhamnosus, Lactobacillus paracasei and L. casei. Regarding the coding region, the spxB functionality in cheese was shown for the first time by real-time PCR, and by exploiting the heterogeneity between the L. casei group species, we identified the bacterial communities encoding the spxB gene in this ecosystem. This study allowed for monitoring of the active bacterial community involved in different stages of ripening by following the POX pathway.
authors.affiliation: Department of Food Science, University of Parma, Parco Area delle Scienze 49/A, 43124 Parma, Italy; Multidisciplinary Interdepartmental Dairy Centre - MILC, University of Parma, Parco Area delle Scienze 95/A, 43124, Parma, Italy.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Savo Sardaro
authors.affiliation: Department of Food Science, University of Parma, Parco Area delle Scienze 49/A, 43124 Parma, Italy; Multidisciplinary Interdepartmental Dairy Centre - MILC, University of Parma, Parco Area delle Scienze 95/A, 43124, Parma, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Levante
authors.affiliation: Department of Food Science, University of Parma, Parco Area delle Scienze 49/A, 43124 Parma, Italy; Multidisciplinary Interdepartmental Dairy Centre - MILC, University of Parma, Parco Area delle Scienze 95/A, 43124, Parma, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Bernini
authors.affiliation: Department of Food Science, University of Parma, Parco Area delle Scienze 49/A, 43124 Parma, Italy; Multidisciplinary Interdepartmental Dairy Centre - MILC, University of Parma, Parco Area delle Scienze 95/A, 43124, Parma, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Gatti
authors.affiliation: Department of Food Science, University of Parma, Parco Area delle Scienze 49/A, 43124 Parma, Italy; Multidisciplinary Interdepartmental Dairy Centre - MILC, University of Parma, Parco Area delle Scienze 95/A, 43124, Parma, Italy.
authors.forename: Erasmo
authors.initials: E
authors.lastname: Neviani
authors.affiliation: Department of Food Science, University of Parma, Parco Area delle Scienze 49/A, 43124 Parma, Italy; Multidisciplinary Interdepartmental Dairy Centre - MILC, University of Parma, Parco Area delle Scienze 95/A, 43124, Parma, Italy. Electronic address: camilla.lazzi@unipr.it.
authors.forename: Camilla
authors.initials: C
authors.lastname: Lazzi
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002611:Cheese / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D018076:DNA, Complementary; D005516:Food Microbiology; D016680:Genome, Bacterial; D007780:Lacticaseibacillus casei / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D000069980:Lacticaseibacillus paracasei / Q000235:genetics; D052201:Lacticaseibacillus rhamnosus / Q000235:genetics; D059013:Microbial Consortia / Q000235:genetics / Q000502:physiology; D011771:Pyruvate Oxidase / Q000235:genetics* / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D016415:Sequence Alignment; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D018076:DNA, Complementary; D012336:RNA, Ribosomal, 16S; D011771:Pyruvate Oxidase
keywords: Cheese; High resolution melting; Lactobacillus casei group; Pyruvate oxidase; Real-time quantitative PCR; spxB gene