Author
Ralph, John | |
LU, FACHUANG - UNIVERSITY OF WISCONSIN | |
MARITA, JANE - UNIVERSITY OF WISCONSIN | |
Hatfield, Ronald | |
LAPIERRE, CATHERINE - INRA-GRIGNON,FRANCE | |
RALPH, SALLY - US FOREST PRODUCTS LAB | |
CHAPPLE, CLINT - PURDUE UNIVERSITY | |
VERMERRIS, WILFRED - PURDUE UNIVERSITY | |
BOERJAN, WOUT - U. GENT,BELGIUM |
Submitted to: Meeting Abstract
Publication Type: Proceedings Publication Acceptance Date: 6/11/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: COMT is the enzyme responsible for methylating 5-hydroxyconiferyl aldehyde, on the way to producing syringyl units. It is deficient in recently examined transgenic poplars downregulated by two different methods, in F5H-upregulated transgenic arabidopsis, and in a brown-midrib maize mutant (bm3). In all cases, 5-hydroxyconiferyl alcohol incorporated intimately into the lignin. Benzodioxane (4-O-beta/5-O-alpha) structures are produced and can be characterized by their beautiful NMR correlations, by their survival through DFRC-degradation, and their partial survival through thioacidolysis. The level of detail revealed by these methods provides evidence that the novel 5-hydroxyconiferyl alcohol monomer cross-couples with syringyl and guaiacyl units into the growing lignin oligomer, and that normal monolignols then add to the new 5-hydroxyguaiacyl terminus producing benzodioxanes. Demonstrated endwise polymerization into lignins suggests that 5-hydroxyconiferyl alcohol shoul be recognized as an authentic lignin monomer in these angiosperms. |