Floral scent production in Clarkia breweri (Onagraceae). II. Localization and developmental modulation of the enzyme S-adenosyl-L-methionine:(iso)eugenol O-methyltransferase and phenylpropanoid emission

• Published in: Plant physiology (Bethesda) 1997-05, Vol.114 (1), p.213-221
• Main Authors: Wang, J. (University of Michigan, East Lansing, MI.), Dudareva, N, Bhakta, S, Raguso, R.A, Pichersky, E
• Format: Article
• Language: English
• Subjects: ACIDE ORGANIQUE; ACIDOS ORGANICOS; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ADN; Agronomy. Soil science and plant productions; Amino Acid Sequence; Anisoles - metabolism; ARN MENSAJERO; ARN MESSAGER; AROMATIC COMPOUNDS; Base Sequence; BIOCHEMICAL PATHWAYS; Biochemistry and Enzymology; Biological and medical sciences; BIOSINTESIS; BIOSYNTHESE; BIOSYNTHESIS; CAFFEIC ACID; CHEMICAL COMPOSITION; CHEMICAL REACTIONS; Cloning, Molecular; CODE GENETIQUE; CODIGO GENETICO; COMPLEMENTARY DNA; COMPOSE AROMATIQUE; COMPOSE PHENOLIQUE; COMPOSE VOLATIL; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; COMPUESTO VOLATIL; COMPUESTOS AROMATICOS; COMPUESTOS FENOLICOS; CULTURE MEDIA; DERIVATIVES; DEVELOPMENTAL STAGES; DNA; DNA, Complementary - genetics; DNA, Plant - genetics; Economic plant physiology; Enzymes; ENZYMIC ACTIVITY; ETAPAS DE DESARROLLO; Eugenol - analogs & derivatives; Eugenol - metabolism; FLEUR; FLORES; Flowering; FLOWERS; FRAGRANCE; Fundamental and applied biological sciences. Psychology; GENBANK/U86760; GENETIC CODE; GENETIC REGULATION; GENETICA; GENETICS; GENETIQUE; ISOEUGENOL; ISOMETHULEUGENOL; MEDIO DE CULTIVO; MESSENGER RNA; Metabolism; Metabolism. Physicochemical requirements; METHIONINE; METHYLATION; METHYLEUGENOL; Methyltransferases - genetics; Methyltransferases - metabolism; METILACION; METIONINA; MILIEU DE CULTURE; MOLECULAR SEQUENCE DATA; Nitrogen metabolism and other ones (excepting carbon metabolism); NUCLEOTIDE SEQUENCE; Nutrition. Photosynthesis. Respiration. Metabolism; ODEUR; ODOR EMISSION; Odorants; OLOR; ONAGRACEAE; ORGANIC ACIDS; Petals; PHENOLIC COMPOUNDS; Plant physiology and development; Plants; Plants - enzymology; Plants - genetics; Plants - metabolism; PRECURSORS; Proteins; REACCIONES QUIMICAS; REACTION CHIMIQUE; RNA; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Plant - genetics; RNA, Plant - metabolism; SECUENCIA NUCLEOTIDICA; SEQUENCE NUCLEOTIDIQUE; SMELL; STADE DE DEVELOPPEMENT; SUBSTRATES; Tissue Distribution; TRANSFERASAS; TRANSFERASE; TRANSFERASES; TRANSLATION; VIA BIOQUIMICA DEL METABOLISMO; VOIE BIOCHIMIQUE DU METABOLISME; VOLATILE COMPOUNDS
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.114.1.213

We have previously shown (R.A. Raguso, E. Pichersky [1995] Plant Syst Evol 194:55-67) that the strong, sweet fragrance of Clarkia breweri (Onagraceae), an annual plant native to California, consists of 8 to 12 volatile compounds, including 4 phenylpropanoids. Although some C. breweri plants emit all 4 phenylpropanoids (eugenol, isoeugenol, methyleugenol, and isomethyleugenol), other C. breweri plants do not emit the latter 2 compounds. Here we report that petal tissue was responsible for the bulk of the phenylpropanoid emission. The activity of S-adenosyl-L-methionine: (iso)eugenol O-methyltransferase (IEMT), a novel enzyme that catalyzes the methylation of the para-4'-hydroxyl of both eugenol and (iso)eugenol to methyleugenol and isomethyleugenol, respectively, was also highest in petal tissue. IEMT activity was absent from floral tissues of plants not emitting (iso)methyleugenol. A C. breweri cDNA clone encoding IEMT was isolated, and its sequence was shown to have 70% identity to S-adenosyl-L-methionine:caffeic acid O-methyltransferase. The protein encoded by this cDNA can use eugenol and isoeugenol as substrates, but not caffeic acid. Steady-state IEMT mRNA levels were positively correlated with levels of IEMT activity in the tissues, and no IEMT mRNA was observed in flowers that do not emit (iso)methyleugenol. Overall, the data show that the floral emission of (iso)methyleugenol is controlled at the site of emission, that a positive correlation exists between volatile emission and IEMT activity, and that control of the level of IEMT activity is exerted at a pretranslational step