Suppression of 4-Coumarate-CoA Ligase in the Coniferous GymnospermPinus radiata
- 29 October 2008
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 149 (1), 370-383
- https://doi.org/10.1104/pp.108.125765
Abstract
Severe suppression of 4-coumarate-coenzyme A ligase (4CL) in the coniferous gymnosperm Pinus radiata substantially affected plant phenotype and resulted in dwarfed plants with a "bonsai tree-like" appearance. Microscopic analyses of stem sections from 2-year-old plants revealed substantial morphological changes in both wood and bark tissues. This included the formation of weakly lignified tracheids that displayed signs of collapse and the development of circumferential bands of axial parenchyma. Acetyl bromide-soluble lignin assays and proton nuclear magnetic resonance studies revealed lignin reductions of 36% to 50% in the most severely affected transgenic plants. Two-dimensional nuclear magnetic resonance and pyrolysis-gas chromatography-mass spectrometry studies indicated that lignin reductions were mainly due to depletion of guaiacyl but not p-hydroxyphenyl lignin. 4CL silencing also caused modifications in the lignin interunit linkage distribution, including elevated beta-aryl ether (beta-O-4 unit) and spirodienone (beta-1) levels, accompanied by lower phenylcoumaran (beta-5), resinol (beta-beta), and dibenzodioxocin (5-5/beta-O-4) levels. A sharp depletion in the level of saturated (dihydroconiferyl alcohol) end groups was also observed. Severe suppression of 4CL also affected carbohydrate metabolism. Most obvious was an up to approximately 2-fold increase in galactose content in wood from transgenic plants due to increased compression wood formation. The molecular, anatomical, and analytical data verified that the isolated 4CL clone is associated with lignin biosynthesis and illustrated that 4CL silencing leads to complex, often surprising, physiological and morphological changes in P. radiata.Keywords
This publication has 63 references indexed in Scilit:
- Evolution and current status of research in phenolic compoundsPhytochemistry, 2007
- Downregulation of Cinnamoyl-Coenzyme A Reductase in Poplar: Multiple-Level Phenotyping Reveals Effects on Cell Wall Polymer Metabolism and StructureTHE PLANT CELL ONLINE, 2007
- Exploring lignification in conifers by silencing hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase in Pinus radiataProceedings of the National Academy of Sciences of the United States of America, 2007
- Flavonoid Accumulation in Arabidopsis Repressed in Lignin Synthesis Affects Auxin Transport and Plant GrowthTHE PLANT CELL ONLINE, 2007
- Microarray gene expression profiling of developmental transitions in Sitka spruce (Picea sitchensis) apical shootsJournal of Experimental Botany, 2007
- Pinus taeda phenylpropenal double-bond reductase: Purification, cDNA cloning, heterologous expression in Escherichia coli, and subcellular localization in P. taedaPhytochemistry, 2006
- Monolignol biosynthesis and genetic engineering of lignin in trees, a reviewEnvironmental Chemistry Letters, 2006
- Look back over the studies of lignin biochemistryJournal of Wood Science, 2006
- Wood Sugar Analysis by Anion ChromatographyJournal of Wood Chemistry and Technology, 1991
- A low-viscosity epoxy resin embedding medium for electron microscopyJournal of Ultrastructure Research, 1969