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Unformatted text preview: Role of Petal-Specific Orcinol O-Methyltransferases in the Evolution of Rose Scent 1 Gabriel Scalliet 2 , Claire Lionnet, Mickae ¨l Le Bechec 3 , Laurence Dutron, Jean-Louis Magnard, Sylvie Baudino, Ve ´ronique Bergougnoux, Fre ´de ´ric Jullien, Pierre Chambrier, Philippe Vergne, Christian Dumas, J. Mark Cock, and Philippe Hugueney* Laboratoire Reproduction et De ´veloppement des Plantes, Unite ´ Mixte de Recherche 5667 Centre National de la Recherche Scientifique-Institut National de la Recherche Agronomique-Ecole Normale Supe ´rieure de Lyon-Universite ´ Claude Bernard Lyon 1, IFR128 Biosciences Lyon-Gerland (G.S., C.L., P.C., P.V., C.D., P.H.), and De ´partement des Sciences de la Vie et de la Terre (M.L.B., L.D.), Ecole Normale Supe ´rieure de Lyon, 69364 Lyon, France; Laboratoire de Biotechnologies Ve ´ge ´tales Applique ´es aux Plantes Aromatiques et Me ´dicinales, Universite ´ Jean Monnet, 42023 Saint-Etienne, France (J.L.M., S.B., V.B., F.J.); and Unite ´ Mixte de Recherche 7139 Centre National de la Recherche Scientifique-Universite ´ Pierre et Marie Curie, Ve ´ge ´taux Marins et Biomole ´cules, 29682 Roscoff, France (J.M.C.) Orcinol O-methyltransferase (OOMT) 1 and 2 catalyze the last two steps of the biosynthetic pathway leading to the phenolic methyl ether 3,5-dimethoxytoluene (DMT), the major scent compound of many rose ( Rosa x hybrida ) varieties. Modern roses are descended from both European and Chinese species, the latter being producers of phenolic methyl ethers but not the former. Here we investigated why phenolic methyl ether production occurs in some but not all rose varieties. In DMT-producing varieties, OOMTs were shown to be localized specifically in the petal, predominanty in the adaxial epidermal cells. In these cells, OOMTs become increasingly associated with membranes during petal development, suggesting that the scent bio- synthesis pathway catalyzed by these enzymes may be directly linked to the cells’ secretory machinery. OOMT gene sequences were detected in two non-DMT-producing rose species of European origin, but no mRNA transcripts were detected, and these varieties lacked both OOMT protein and enzyme activity. These data indicate that up-regulation of OOMT gene expression may have been a critical step in the evolution of scent production in roses. The past 10 years have seen rapid progress in flower scent research, the initial breakthrough coming from the pioneering work on ( S )-linalool synthase from flowers of Clarkia breweri (Pichersky et al., 1995). The purification of ( S )-linalool synthase provided amino acid sequence information that allowed the isolation of the corresponding gene (Dudareva et al., 1996). The characterization of additional genes involved in the biosynthesis of floral volatiles in C. breweri followed, including those encoding enzymes for the synthesis of the phenylpropanoids methyl eugenol and methyl isoeugenol (Wang et al., 1997), benzyl acetate (Dudareva et al., 1998), and methyl salicylate (Ross et al., 1999).et al....
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This note was uploaded on 08/01/2009 for the course HORT hor-11-12 taught by Professor Park during the Spring '09 term at A.T. Still University.
- Spring '09