title: Description of the mechanisms underlying geosmin production in Penicillium expansum using proteomics.
abstract: A 2D-DIGE proteomics experiment was performed to describe the mechanism underlying the production of geosmin, an earthy-smelling sesquiterpene which spoils wine, produced by Penicillium expansum. The strains were identified by sequencing of the ITS and beta-tubulin regions. This study was based on a selection of four strains showing different levels of geosmin production, assessed by GC-MS/MS. The proteomics study revealed the differential abundance of 107 spots between the different strains; these were picked and submitted to MALDI-TOF-TOF MS analysis for identification. They belonged to the functional categories of protein metabolism, redox homeostasis, metabolic processes (glycolysis, ATP production), cell cycle and cell signalling pathways. From these data, an implication of oxidative stress in geosmin production may be hypothesized. Moreover, the differential abundance of some glycolytic enzymes may explain the different patterns of geosmin biosynthesis. This study provides data for the characterisation of the mechanism and the regulation of the production of this off-flavour, which are so far not described in filamentous fungi.
  
  
  CONCLUSIONS
  Green mould on grapes, caused by P. expansum may be at the origin of off-flavours in wine. These are characterized by earthy-mouldy smells and are due to the presence of the compound geosmin. This work aims at describing how geosmin is produced by P. expansum. This knowledge is of use for the research community on grapes for understanding why these off-flavours occasionally occur in vintages.
authors.affiliation: Centre de Recherche Public-Gabriel Lippmann, Département Environnement et Agro-biotechnologies, Belvaux, Luxembourg. Electronic address: behr@lippmann.lu.
authors.forename: Marc
authors.initials: M
authors.lastname: Behr
authors.affiliation: Centre de Recherche Public-Gabriel Lippmann, Département Environnement et Agro-biotechnologies, Belvaux, Luxembourg. Electronic address: serchi@lippmann.lu.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Serchi
authors.affiliation: Centre de Recherche Public-Gabriel Lippmann, Département Environnement et Agro-biotechnologies, Belvaux, Luxembourg. Electronic address: cocco@lippmann.lu.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Cocco
authors.affiliation: Centre de Recherche Public-Gabriel Lippmann, Département Environnement et Agro-biotechnologies, Belvaux, Luxembourg. Electronic address: guignard@lippmann.lu.
authors.forename: Cédric
authors.initials: C
authors.lastname: Guignard
authors.affiliation: Centre de Recherche Public-Gabriel Lippmann, Département Environnement et Agro-biotechnologies, Belvaux, Luxembourg. Electronic address: sergeant@lippmann.lu.
authors.forename: Kjell
authors.initials: K
authors.lastname: Sergeant
authors.affiliation: Centre de Recherche Public-Gabriel Lippmann, Département Environnement et Agro-biotechnologies, Belvaux, Luxembourg. Electronic address: renaut@lippmann.lu.
authors.forename: Jenny
authors.initials: J
authors.lastname: Renaut
authors.affiliation: Centre de Recherche Public-Gabriel Lippmann, Département Environnement et Agro-biotechnologies, Belvaux, Luxembourg. Electronic address: evers@lippmann.lu.
authors.forename: Danièle
authors.initials: D
authors.lastname: Evers
mesh_terms: D005656:Fungal Proteins / Q000378:metabolism*; D006019:Glycolysis / Q000502:physiology; D013058:Mass Spectrometry; D009284:Naphthols / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D010407:Penicillium / Q000378:metabolism*; D040901:Proteomics
chemical_list: D005656:Fungal Proteins; D009284:Naphthols; C001278:geosmin
keywords: Geosmin; ITS; MEP pathway; MVA pathway; Oxidative stress; PH-like; PTV; Penicillium expansum; Proteomics; internal transcribed spacer (of the rDNA); methylerythritol phosphate pathway; mevalonate pathway; pleckstrin homology-like; programmed temperature vaporization