Jean-Claude Caissard & Sylvie Baudino Laboratoire de Biotechnologies Végétales appliquées aux Plantes Aromatiques et Médicinales (EA 3061) Université Jean Monnet 23 rue du Dr Michelon 42023 Saint-Etienne Cedex 2 Garden roses Roses for perfumes Breeding for diversity of scents Breeding for yield increase Cut roses Breeding for long vase life AND scent BUT SCENT IS A COMPLEX TRAIT Understanding the biosynthesis of rose scent and its regulation 2-phenylethyl-β-Dglucopyranoside OH Regulation of an hypothetic βglucosidase is sufficient to explain the 2-phenylethanol phenology during blooming RhPAAS COOH NH2 OH O RoPAR O 2-phenylacetaldehyde synthase L-phenylalanine OH 2-phenylacetaldehyde reductase 2-phenylacetaldehyde 2-phenylethanol O RhAAT phenylpyruvate alcohol acetyltransferase COOH RdAAAT3 OH O β-glucosidase/glycosyl transferase Alleles of PAAS can explain variations in 2-phenylethanol quantity O 2-phenylethyl acetate O