Skip to Main Content
Lignification in transgenics deficient in 4-coumarate 3-hydroxylase (C3H)or the associated hydroxycinnamoyl transferase (HCT)Author(s): John Ralph; Takuya Akiyama; Hoon Kim; Fachuang Lu; Sally A. Ralph; Clint Chapple; Ramesh B. Nair; Armin Wagner; Fang Chen; M.S. Srinivasa Reddy; Richard A Dixon; Heather D. Coleman; Shawn D. Mansfield
Source: Polyphenols communications 2006 : XXIII International Conference on Polyphenols, Winnipeg, Manitoba, Canada, August 22-25, 2006. [Winnipeg] : University of Manitoba, : ISBN: 0978158903: 9780978158903:  pages.
Publication Series: Miscellaneous Publication
PDF: View PDF (286 KB)
DescriptionDown-regulation of the gene encoding 4-coumarate 3-hydroxylase (C3H) in angiosperms massively but predictably increased the proportion of p-hydroxyphenyl (P) units relative to the normally dominant syringyl (S) and guaiacyl (G) units. Alfalfa stem levels of up to ~65% P (from wild-type (WT) levels of ~1%) resulting from down-regulation of C3H were measured by traditional degradative analyses as well as 2D 13C– 1H correlative NMR methods. Such levels put these transgenics well beyond the P:G:S compositional bounds of normal plants. NMR also revealed structural differences in the interunit linkage distribution that characterizes a lignin polymer. Less severely elevated P-levels were also detected in C3H-downreulated poplar and in HCT-downregulated P. radiata tracheid cultures, but with different structural effects. The compositional and structural changes remain consistent with the existing theory of lignification based on combinatorial radical coupling reactions under simple chemical control. Such structural differences form a basis for explaining differences in digestibility and pulping performance of C3H/HCT-deficient plants.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationRalph, John; Akiyama, Takuya; Kim, Hoon; Lu, Fachuang; Ralph, Sally A.; Chapple, Clint; Nair, Ramesh B.; Wagner, Armin; Chen, Fang; Reddy, M.S. Srinivasa; Dixon, Richard A; Coleman, Heather D.; Mansfield, Shawn D. 2006. Lignification in transgenics deficient in 4-coumarate 3-hydroxylase (C3H)or the associated hydroxycinnamoyl transferase (HCT). Polyphenols communications 2006 : XXIII International Conference on Polyphenols, Winnipeg, Manitoba, Canada, August 22-25, 2006. [Winnipeg] : University of Manitoba, : ISBN: 0978158903: 9780978158903:  pages.
KeywordsBiosynthesis, enzymes, biotechnology, nuclear magnetic resonance spectroscopy, lignin analysis, genetic engineering, coumarins, lignification, pulping, alfalfa, transgenic plants, poplar, Pinus radiata, down-regulation, pulp and paper processes, guaiacyl, syringyl, coumarate 3-hydroxylate, hydroxyphenyl
- Soil sulfur amendments suppress Selenium uptake by alfalfa and western wheatgrass
- Removal of toxic heavy metal ions in runoffs by modified alfalfa and juniper
- Effects of coumarate 3-hydroxylase down-regulation on lignin structure
XML: View XML