title: Tyrosinase expression during black truffle development: from free living mycelium to ripe fruit body.
abstract: The present work studies the expression of tyrosinase (monophenol:diphenol oxygen oxidoreductase, EC 1.14.18.1) during the development of the black truffle Tuber melanosporum Vittad., an ectomycorrhizal fungus of great biological and economic interest. As widely reported in the literature, melanins and the enzymes that synthesize them, are of paramount importance in fungal development and sexual differentiation. Tyrosinase and laccase are the enzymes that produce melanins from monophenols and diphenols. We have detected tyrosinase expression from the stage of free living mycelium, through the mychorrizal stage and the six fruit body developmental stages by measuring the levels of tyrosinase mRNA by quantitative PCR (q-PCR), spectrophotometry, histochemistry, immunohistochemistry and electrophoresis. Tyrosinase is always expressed, from the free living mycelium to the ripe fruit body developmental stages, when it is very low. The switching off of the tyrosinase gene during T. melanosporum development when the fruit body is ripe and no more cell walls are to be built is discussed in relation of thioflavour production. Specific primers, prepared from the cloned T. melanosporum tyrosinase cDNA were used for the q-PCR and the deduced aminoacid sequences of the CuA and CuB binding sites were compared to those of various ascomycetes and basidiomycetes.
authors.affiliation: Department of Basic and Applied Biology, University of L'Aquila, I 67010 Coppito-L'Aquila, Italy.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Zarivi
authors.forename: Antonella
authors.initials: A
authors.lastname: Bonfigli
authors.forename: Sabrina
authors.initials: S
authors.lastname: Colafarina
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Aimola
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Ragnelli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pacioni
authors.forename: Michele
authors.initials: M
authors.lastname: Miranda
mesh_terms: D000595:Amino Acid Sequence; D001203:Ascomycota / Q000201:enzymology* / Q000254:growth & development; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016681:Genome, Fungal; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025282:Mycelium / Q000201:enzymology* / Q000254:growth & development; D038821:Mycorrhizae / Q000201:enzymology* / Q000254:growth & development
chemical_list: D005656:Fungal Proteins; D014442:Monophenol Monooxygenase