title: Investigation of Geotrichum candidum gene expression during the ripening of Reblochon-type cheese by reverse transcription-quantitative PCR.
abstract: Cheese ripening involves the activity of various bacteria, yeasts or molds, which contribute to the development of the typical color, flavor and texture of the final product. In situ measurements of gene expression are increasingly being used to improve our understanding of the microbial flora activity in cheeses. The objective of the present study was to investigate the physiology and metabolic activity of Geotrichum candidum during the ripening of Reblochon-type cheeses by quantifying mRNA transcripts at various ripening times. The expression of 80 genes involved in various functions could be quantified with a correct level of biological repeatability using a set of three stable reference genes. As ripening progresses, a decrease in expression was observed for genes involved in cell wall organization, translation, vesicular mediated transport, and in cytoskeleton constituents and ribosomal protein genes. There was also a decrease in the expression of mitochondrial F1F0 ATP synthase and plasma membrane H(+) ATPase genes. Some genes involved in the catabolism of lactate, acetate and ethanol were expressed to a greater extent at the beginning of ripening. During the second part of ripening, there was an increased expression of genes involved in the transport and catabolism of amino acids, which could be attributed to a change in the energy source. There was also an increase in the expression of genes involved in autophagy and of genes possibly involved in lifespan determination. Quantification of mRNA transcripts may also be used to produce bioindicators relevant for cheesemaking, for example when considering genes encoding enzymes involved in the catabolism of amino acids.
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, 78850 Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, 78850 Thiverval-Grignon, France.
authors.forename: Jessie
authors.initials: J
authors.lastname: Castellote
authors.affiliation: Actalia Produits Laitiers, 74800 La Roche-sur-Foron, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Fraud
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, 78850 Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, 78850 Thiverval-Grignon, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Irlinger
authors.affiliation: INRA, UMR1319 Micalis, 78850 Thiverval-Grignon, France; AgroParisTech, UMR1319 Micalis, 78850 Thiverval-Grignon, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Swennen
authors.affiliation: INRA, UMR1319 Micalis, 78850 Thiverval-Grignon, France; INRA, UMR518 Mathématiques et Informatique Appliquées, 75005 Paris, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Fer
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, 78850 Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, 78850 Thiverval-Grignon, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Bonnarme
authors.affiliation: INRA, UMR782 Génie et Microbiologie des Procédés Alimentaires, 78850 Thiverval-Grignon, France; AgroParisTech, UMR782 Génie et Microbiologie des Procédés Alimentaires, 78850 Thiverval-Grignon, France. Electronic address: monnet@grignon.inra.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Monnet
mesh_terms: D002611:Cheese / Q000382:microbiology*; D005516:Food Microbiology; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal / Q000235:genetics; D005848:Geotrichum / Q000235:genetics* / Q000378:metabolism
keywords: Cheese; Gene expression; Geotrichum candidum; Reblochon; Reverse transcription-quantitative PCR; mRNA