title: A temporal-omic study of Propionibacterium freudenreichii CIRM-BIA1 adaptation strategies in conditions mimicking cheese ripening in the cold.
abstract: Propionibacterium freudenreichii is used as a ripening culture in Swiss cheese manufacture. It grows when cheeses are ripened in a warm room (about 24°C). Cheeses with an acceptable eye formation level are transferred to a cold room (about 4°C), inducing a marked slowdown of propionic fermentation, but P. freudenreichii remains active in the cold. To investigate the P. freudenreichii strategies of adaptation and survival in the cold, we performed the first global gene expression profile for this species. The time-course transcriptomic response of P. freudenreichii CIRM-BIA1(T) strain was analyzed at five times of incubation, during growth at 30°C then for 9 days at 4°C, under conditions preventing nutrient starvation. Gene expression was also confirmed by RT-qPCR for 28 genes. In addition, proteomic experiments were carried out and the main metabolites were quantified. Microarray analysis revealed that 565 genes (25% of the protein-coding sequences of P. freudenreichii genome) were differentially expressed during transition from 30°C to 4°C (P<0.05 and |fold change|>1). At 4°C, a general slowing down was observed for genes implicated in the cell machinery. On the contrary, P. freudenreichii CIRM-BIA1(T) strain over-expressed genes involved in lactate, alanine and serine conversion to pyruvate, in gluconeogenesis, and in glycogen synthesis. Interestingly, the expression of different genes involved in the formation of important cheese flavor compounds, remained unchanged at 4°C. This could explain the contribution of P. freudenreichii to cheese ripening even in the cold. In conclusion, P. freudenreichii remains metabolically active at 4°C and induces pathways to maintain its long-term survival.
authors.affiliation: INRA (French National Institute for Agricultural Research), UMR1253 Science et Technologie du Lait et de l'OEuf, Rennes, France [corrected].
authors.forename: Marion
authors.initials: M
authors.lastname: Dalmasso
authors.forename: Julie
authors.initials: J
authors.lastname: Aubert
authors.forename: Valérie
authors.initials: V
authors.lastname: Briard-Bion
authors.forename: Victoria
authors.initials: V
authors.lastname: Chuat
authors.forename: Stéphanie-Marie
authors.initials: SM
authors.lastname: Deutsch
authors.forename: Sergine
authors.initials: S
authors.lastname: Even
authors.forename: Hélène
authors.initials: H
authors.lastname: Falentin
authors.forename: Gwénaël
authors.initials: G
authors.lastname: Jan
authors.forename: Julien
authors.initials: J
authors.lastname: Jardin
authors.forename: Marie-Bernadette
authors.initials: MB
authors.lastname: Maillard
authors.forename: Sandrine
authors.initials: S
authors.lastname: Parayre
authors.forename: Michel
authors.initials: M
authors.lastname: Piot
authors.forename: Jarna
authors.initials: J
authors.lastname: Tanskanen
authors.forename: Anne
authors.initials: A
authors.lastname: Thierry
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D002611:Cheese; D003080:Cold Temperature; D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D050296:Microbial Viability; D011424:Propionibacterium / Q000235:genetics* / Q000502:physiology*; D020543:Proteome / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics; D013997:Time Factors; D059467:Transcriptome / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D020543:Proteome; D002244:Carbon