Project description:Propionibacterium freudenreichii is an important starter culture used in the manufacture of Swiss-type cheeses. We have generated the complete genome sequence of a Propionibacterium freudenreichii ssp. shermanii strain JS at the Institute of Biotechnology, University of Helsinki, by using a combination of pyrosequencing with GS FLX and GS FLX Titanium series reagents (Roche) and SOLiD 4 (Life Technologies), ABI 3130xl Genetic Analyzer (Life Technologies), and PacBio RS II (Pacific Biosciences) instruments. Initial genome annotation was carried out using RAST, and additional functional annotation information for each CDS was obtained from BLANNOTATOR, CDD, and KAAS. Accession number for genome sequence is PRJEB12148. This submission is for the transcriptome analysis of Propionibakcterium freudenreichii in cheese ripening under warm and cold conditions. The RNA reads were mapped to the reference genome PRJEB12148.
Project description:Propionibacterium freudenreichii is used as a ripening culture in Swiss cheese manufacture. It produces flavor compounds over the whole ripening period. During cheese ripening, P. freudenreichii is exposed to a temperature downshift, especially when cheeses are transferred from warm temperature (about 24°C) to cold temperature (about 4°C). The aim of this study was to investigate the adaptation of P. freudenreichii at cold temperature by means of the first global gene expression profile for this species. The temporal transcriptomic response of P. freudenreichii was analyzed at five times of growth, during growth at 30°C then for 9 days at 4°C, in the constant presence of lactate as the main carbon source. P. freudenreichii response was also investigated by RT-qPCR for 30 genes, by proteomics and metabolomics (main metabolites quantified in culture supernatant). Microarray analysis revealed that 565 genes (25% of the protein-coding sequences of P. freudenreichii genome) were differentially expressed during transition from warm to cold temperature (P < 0.05 and |fold change| > 1). Most of the down-expressed genes were involved in cell machinery (cell division, protein turnover, translation, transcription and DNA replication). During incubation at cold temperature, P. freudenreichii accumulated carbon supplies by up-regulating genes involved in lactate, alanine and serine conversion to pyruvate, in gluconeogenesis and in glycogen synthesis. Interestingly, some genes involved in the formation of important flavor compounds of cheese, coding for an extracellular lipolytic esterases and enzymes of the pathways of formation of branched-chain compounds, were not significantly affected by cold. In conclusion, P. freudenreichii is metabolically active at cold temperature and induces pathways to maintain its long-term viability, which could explain its contribution to cheese ripening even at low temperature.
Project description:This study was performed to monitor ethylene glycol metabolism by Propionibacterium freudenreichii and to elucidate the metabolic pathway involved.
