title: 3-Sulfanylhexanol precursor biogenesis in grapevine cells: the stimulating effect of Botrytis cinerea.
abstract: Volatile thiols, compounds that contribute strongly to the varietal aroma, are present in much higher concentrations in sweet wines than in dry wines. This positive effect, due to the presence of Botrytis cinerea on the berries, in fact results from a strong enrichment of cysteine S-conjugate precursors in botrytized berries. In the present study, a convenient model was investigated to reproduce and therefore study this phenomenon. A Vitis vinifera cell culture was used as a simple model, and we focused on S-3-(hexan-1-ol)-l-cysteine (P-3SH), the cysteinylated precursor of 3-sulfanylhexanol. We demonstrated that grapevine cells were able to produce P-3SH and that the presence of B. cinerea considerably increased the precursor level (up to 1000-fold). This positive result was determined to be due to metabolites secreted by the fungus. These molecules were temperature sensitive, unstable over time, and their production was activated in the presence of grapevine cells. Moreover, part of the pathway leading to P-3SH was deciphered: it was directly derived from the cleavage of S-3-(hexan-1-ol)-l-glutathione, which itself was generated after a conjugation of glutathione on (E)-2-hexenal.
authors.affiliation: Université de Bordeaux , UMR 1219 Œnologie, INRA, ISVV, 210 chemin de Leysotte, CS 50008, Villenave d'Ornon, F-33882, France. cecile.thibon@u-bordeaux2.fr
authors.forename: Cécile
authors.initials: C
authors.lastname: Thibon
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Cluzet
authors.forename: Jean Michel
authors.initials: JM
authors.lastname: Mérillon
authors.forename: Philippe
authors.initials: P
authors.lastname: Darriet
authors.forename: Denis
authors.initials: D
authors.lastname: Dubourdieu
mesh_terms: D020171:Botrytis / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D003545:Cysteine / Q000031:analogs & derivatives; D005638:Fruit / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology; D005978:Glutathione / Q000378:metabolism; D000441:Hexanols / Q000378:metabolism*; D009812:Odorants / Q000032:analysis; D018547:Plant Stems / Q000166:cytology / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D027843:Vitis / Q000166:cytology / Q000378:metabolism*; D014920:Wine / Q000032:analysis
chemical_list: D000441:Hexanols; D013438:Sulfhydryl Compounds; D005978:Glutathione; D003545:Cysteine; C477019:3-mercaptohexanol