Fractional Separation of Middle Lamella and Secondary Wall Tissue From Spruce Wood

Whiting, Philip; Favis, Basil D.; St-Germain, François; Goring, D. A. I.

doi:10.1080/02773818108085092

Cited by 60 publications

(28 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The lignin fraction of CWR was analyzed both quantitatively and qualitatively. Klason lignin content was determined using a micro-Klason technique (Whiting et al, 1981), and the monomeric composition of the non-condensed fraction of lignin was determined by thioacidolysis according to the method of Lapierre et al (1986). Both micro-Klason and thioacidolysis measurements were performed on three wild-type plants and three individuals from each of the transgenic lines, and the whole experiment was duplicated with similar results.…”

Section: Lignin Analysismentioning

confidence: 99%

Metabolite Profiling Reveals a Role for Atypical Cinnamyl Alcohol Dehydrogenase CAD1 in the Synthesis of Coniferyl Alcohol in Tobacco Xylem

et al. 2005

View full text Add to dashboard Cite

In angiosperms, lignin is built from two main monomers, coniferyl and sinapyl alcohol, which are incorporated respectively as G and S units in the polymer. The last step of their synthesis has so far been considered to be performed by a family of dimeric cinnamyl alcohol dehydrogenases (CAD2). However, previous studies on Eucalyptus gunnii xylem showed the presence of an additional, structurally unrelated, monomeric CAD form named CAD1. This form reduces coniferaldehyde to coniferyl alcohol, but is inactive on sinapaldehyde. In this paper, we report the functional characterization of CAD1 in tobacco (Nicotiana tabacum L.). Transgenic tobacco plants with reduced CAD1 expression were obtained through an RNAi strategy. These plants displayed normal growth and development, and detailed biochemical studies were needed to reveal a role for CAD1. Lignin analyses showed that CAD1 down-regulation does not affect Klason lignin content, and has a moderate impact on G unit content of the non-condensed lignin fraction. However, comparative metabolic profiling of the methanol-soluble phenolic fraction from basal xylem revealed significant differences between CAD1 down-regulated and wild-type plants. Eight compounds were less abundant in CAD1 down-regulated lines, five of which were identified as dimers or trimers of monolignols, each containing at least one moiety derived from coniferyl alcohol. In addition, 3-trans-caffeoyl quinic acid accumulated in the transgenic plants. Together, our results support a significant contribution of CAD1 to the synthesis of coniferyl alcohol in planta, along with the previously characterized CAD2 enzymes.

show abstract

Section: Lignin Analysismentioning

confidence: 99%

Metabolite Profiling Reveals a Role for Atypical Cinnamyl Alcohol Dehydrogenase CAD1 in the Synthesis of Coniferyl Alcohol in Tobacco Xylem

et al. 2005

View full text Add to dashboard Cite

show abstract

“…While studies of the chemical heterogeneity of lignin in different cell wall regions are numerous (Whiting et al 1981;Whiting, Goring 1982;Westermark 1985), there are very few reports dealing with the physical properties of the lignin polymer. Agarwal and Atalla (1986) used a Raman microprobe to investigate the physical organisation of lignin in the cell wall of black spruce tracheids.…”

Section: Introductionmentioning

confidence: 99%

Mechanical constraints on lignin deposition during lignification

Donaldson

1994

Wood Sci.Technol.

View full text Add to dashboard Cite

The ultrastructure of lignifying cell walls in Pinus radiata D.Don was investigated using potassium permanganate staining and transmission electron microscopy. Lignin deposition occurred at numerous discrete sites within various cell wall regions, suggesting the presence of some initiating agent at these sites. In the middle lamella region, lignin deposition occurred by addition of protolignin monomers to spherical particles of lignin. Lignification was completed by expansion of these spherical particles, initially forming irregular patterns of lignification followed by infilling of adjacent areas. In contrast, lignification in the secondary wall occurred by deposition of protolignin monomers onto the ends of expanding lignin lamellae between cellulose microfibrils leading to greatly elongated patches of lignin due to the greater rate of deposition along the microflbril axis compared to that across it. It is concluded that the cellulose matrix in which lignin deposition occurs, in the secondary wail, can exert a mechanical influence which limits the rate of lignin deposition in the direction perpendicular to the microfibril axis.

show abstract

“…Lignin analyses were performed on extract-free cell wall residue. The lignin content was estimated by the Klason procedure (Whitting et al, 1981). The lignin monomeric composition was determined by thioacidolysis followed by gas chromatography-mass spectrometry of lignin-derived monomer trimethylsilyl derivatives (Lapierre et al, 1986).…”

Section: Lignin Analysismentioning

confidence: 99%

Down-Regulation of Caffeic Acid O-Methyltransferase in Maize Revisited Using a Transgenic Approach

Piquemal

Chamayou

Nadaud³

et al. 2002

Plant Physiology

157

105

View full text Add to dashboard Cite

Transgenic maize (Zea mays) plants were generated with a construct harboring a maize caffeic acid O-methyltransferase (COMT) cDNA in the antisense (AS) orientation under the control of the maize Adh1 (alcohol dehydrogenase) promoter. Adh1-driven ␤-glucuronidase expression was localized in vascular tissues and lignifying sclerenchyma, indicating its suitability in transgenic experiments aimed at modifying lignin content and composition. One line of AS plants, COMT-AS, displayed a significant reduction in COMT activity (15%-30% residual activity) and barely detectable amounts of COMT protein as determined by western-blot analysis. In this line, transgenes were shown to be stably integrated in the genome and transmitted to the progeny. Biochemical analysis of COMT-AS showed: (a) a strong decrease in Klason lignin content at the flowering stage, (b) a decrease in syringyl units, (c) a lower p-coumaric acid content, and (d) the occurrence of unusual 5-OH guaiacyl units. These results are reminiscent of some characteristics already observed for the maize bm3 (brownmidrib3) mutant, as well as for COMT down-regulated dicots. However, as compared with bm3, COMT down-regulation in the COMT-AS line is less severe in that it is restricted to sclerenchyma cells. To our knowledge, this is the first time that an AS strategy has been applied to modify lignin biosynthesis in a grass species.Lignins are complex phenolic polymers present in all vascular plants. They provide rigidity to conducting xylem elements and fiber cells. Lignins are composed of C 6 C 3 units, principally p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) units, and are present in various proportions according to botanical, physiological, and cytological criteria (Lewis and Yamamoto, 1990). Throughout the plant kingdom, grass lignins appear to be particularly specialized because they contain not only H, G, and S units, but also additional p-hydroxycinnamic units such as p-coumaric and ferulic acids (Higuchi et al., 1967). Ferulic acid may be ester linked to wall polysaccharides and/or ether linked to G units, thereby forming bridges between lignins and polysaccharides (Jacquet et al., 1995), whereas p-coumaric acid is primarily ester linked to S lignin units in lignified walls (Ralph et al., 1994; Grabber et al., 1996).Lignification in dicotyledons has been extensively studied and most of the known lignin biosynthetic genes have been employed in genetic engineering experiments (for review, see Grima-Pettenati and Goffner, 1999). There are almost no molecular data on lignification in grasses (Collazo et al., 1992;McAlister et al., 1998;Pichon et al., 1998;Selman-Housein et al., 1999;Spangenberg et al., 2001). Although lignification in grass species is likely to share a high degree of similarity to other angiosperms, the aforementioned structural specificity of grass cell walls may also involve a certain degree of grass-specific regulatory mechanisms. An in-depth knowledge of lignification in Graminaeae is of utmost importance because lignins are one of the ...

show abstract

Fractional Separation of Middle Lamella and Secondary Wall Tissue From Spruce Wood

Cited by 60 publications

References 6 publications

Metabolite Profiling Reveals a Role for Atypical Cinnamyl Alcohol Dehydrogenase CAD1 in the Synthesis of Coniferyl Alcohol in Tobacco Xylem

Metabolite Profiling Reveals a Role for Atypical Cinnamyl Alcohol Dehydrogenase CAD1 in the Synthesis of Coniferyl Alcohol in Tobacco Xylem

Mechanical constraints on lignin deposition during lignification

Down-Regulation of Caffeic Acid O-Methyltransferase in Maize Revisited Using a Transgenic Approach

Contact Info

Product

Resources

About