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Titolo:
Elucidation of new structures in lignins of CAD- and COMT-deficient plantsby NMR
Autore:
Ralph, J; Lapierre, C; Marita, JM; Kim, H; Lu, FC; Hatfield, RD; Ralph, S; Chapple, C; Franke, R; Hemm, MR; Van Doorsselaere, J; Sederoff, RR; OMalley, DM; Scott, JT; MacKay, JJ; Yahiaoui, N; Boudet, AM; Pean, M; Pilate, G; Jouanin, L; Boerjan, W;
Indirizzi:
USDA ARS, US Dairy Forage Res Ctr, Madison, WI 53706 USA USDA ARS MadisonWI USA 53706 Dairy Forage Res Ctr, Madison, WI 53706 USA Univ Wisconsin, Dept Forestry, Madison, WI 53706 USA Univ Wisconsin Madison WI USA 53706 Dept Forestry, Madison, WI 53706 USA Inst Natl Agron, Chim Biol Lab, F-78850 Thiverval Grignon, France Inst Natl Agron Thiverval Grignon France F-78850 iverval Grignon, France USDA ARS, US Forest Prod Lab, Madison, WI 53706 USA USDA ARS Madison WI USA 53706 , US Forest Prod Lab, Madison, WI 53706 USA Purdue Univ, Dept Biochem, W Lafayette, IN 47907 USA Purdue Univ W Lafayette IN USA 47907 t Biochem, W Lafayette, IN 47907 USA Vlaams Interuniv Inst Biotechnol, Dept Plantengenet, B-9000 Ghent, BelgiumVlaams Interuniv Inst Biotechnol Ghent Belgium B-9000 000 Ghent, Belgium N Carolina State Univ, Dept Genet, Raleigh, NC 27695 USA N Carolina State Univ Raleigh NC USA 27695 t Genet, Raleigh, NC 27695 USA Inst Paper Sci & Technol, Atlanta, GA 30318 USA Inst Paper Sci & Technol Atlanta GA USA 30318 hnol, Atlanta, GA 30318 USA Pole Biotechnol Vegetale, UMR 5546, F-31326 Castanet Tolosan, France Pole Biotechnol Vegetale Castanet Tolosan France F-31326 Tolosan, France DEVM, DSV, Commissariat Energie Atom Cadarache, Grp Rech Appl Phytotechnol, St Paul Durance, France DEVM St Paul Durance France Appl Phytotechnol, St Paul Durance, France Inst Natl Agron, Unite Ameliorat Genet & Physiol Forestieres, F-45166 Olivet, France Inst Natl Agron Olivet France F-45166 orestieres, F-45166 Olivet, France Inst Natl Agron, F-78026 Versailles, France Inst Natl Agron Versailles France F-78026 on, F-78026 Versailles, France
Titolo Testata:
PHYTOCHEMISTRY
fascicolo: 6, volume: 57, anno: 2001,
pagine: 993 - 1003
SICI:
0031-9422(200107)57:6<993:EONSIL>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
CINNAMYL-ALCOHOL-DEHYDROGENASE; O-METHYLTRANSFERASE ACTIVITY; CYTOCHROME P450-DEPENDENT MONOOXYGENASE; MUTANT PINE DEFICIENT; TRANSGENIC TOBACCO; DOWN-REGULATION; FERULATE 5-HYDROXYLASE; CONIFERYL ALDEHYDE; BIOSYNTHESIS; LIGNIFICATION;
Keywords:
NMR; transgenic; mutant; O-methyltransferase; monolignol; coniferyl aldehyde; sinapyl aldehyde; 5-hydroxyconiferyl alcohol;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Ralph, J USDA ARS, US Dairy Forage Res Ctr, 1925 Linden Dr W, Madison, WI 53706 USA USDA ARS 1925 Linden Dr W Madison WI USA 53706 ison, WI 53706 USA
Citazione:
J. Ralph et al., "Elucidation of new structures in lignins of CAD- and COMT-deficient plantsby NMR", PHYTOCHEM, 57(6), 2001, pp. 993-1003

Abstract

Studying lignin-biosynthetic-pathway mutants and transgenics provides insights into plant responses to perturbations of the lignification system, andenhances our understanding of normal lignification. When enzymes late in the pathway are downregulated, significant changes in the composition and structure of lignin may result, NMR spectroscopy provides powerful diagnostictools for elucidating structures in the difficult lignin polymer, hinting at the chemical and biochemical changes that have occurred. COMT (caffeic acid O-methyl transferase) downregulation in poplar results in the incorporation of 5-hydroxyconiferyl alcohol into lignins via typical radical coupling reactions, but post-coupling quinone methide internal trapping reactions produce novel benzodioxane units in the lignin. CAD (cinnamyl alcohol dehydrogenase) downregulation results in the incorporation of the hydroxycinnamyl aldehyde monolignol precursors intimately into the polymer. Sinapyl aldehyde cross-couples 8-O-4 with both guaiacyl and syringyl units in the growing polymer. whereas coniferyl aldehyde cross-couples 8-O-4 only with syringyl units, reflecting simple chemical cross-coupling propensities. The incorporation of hydroxycinnamyl aldehyde and 5-hydroxyconiferyl alcohol monomersindicates that these monolignol intermediates are secreted to the cell wall for lignification. The recognition that novel units can incorporate into lignins portends significantly expanded opportunities for engineering the composition and consequent properties of lignin for improved utilization of valuable plant resources. (C) 2001 Elsevier Science Ltd. All rights reserved.

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Documento generato il 03/12/20 alle ore 05:42:06