Antisense Suppression of 4-Coumarate:Coenzyme A Ligase Activity in Arabidopsis Leads to Altered Lignin Subunit Composition

Lee, Diana; Meyer, Knut Andreas; Chapple, Clint; Douglas, Carl J.

doi:10.2307/3870559

Cited by 57 publications

(78 citation statements)

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“…However, the transgenic plants displayed abnormal plant growth and development (Elkind et al, 1990;Piquemal et al, 1998;Tamagnone et al, 1998), indicating that Phe ammonia-lyase, cinnamoyl-coenzyme A reductase, and Myb proteins are not ideal targets for genetic manipulation of lignin in forages and trees. In contrast, transgenic plants with repression of genes such as 4-coumarate:coenzyme A ligase (Kajita et al, 1996;Lee et al, 1998;Hu et al, 1999) and CCoAOMT showed normal growth patterns, suggesting that these genes are ideal targets for genetic manipulation of lignin in forages and trees.…”

Section: Ccoaomt Is An Ideal Target For Genetic Manipulation Of Lignimentioning

confidence: 95%

Essential Role of Caffeoyl Coenzyme A O-Methyltransferase in Lignin Biosynthesis in Woody Poplar Plants

et al. 2000

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Caffeoyl coenzyme A O-methyltransferase (CCoAOMT) has recently been shown to participate in lignin biosynthesis in herbacious tobacco plants. Here, we demonstrate that CCoAOMT is essential in lignin biosynthesis in woody poplar (Populus tremula ϫ Populus alba) plants. In poplar stems, CCoAOMT was found to be expressed in all lignifying cells including vessel elements and fibers as well as in xylem ray parenchyma cells. Repression of CCoAOMT expression by the antisense approach in transgenic poplar plants caused a significant decrease in total lignin content as detected by both Klason lignin assay and Fourier-transform infrared spectroscopy. The reduction in lignin content was the result of a decrease in both guaiacyl and syringyl lignins as determined by in-source pyrolysis mass spectrometry. Fourier-transform infrared spectroscopy indicated that the reduction in lignin content resulted in a less condensed and less cross-linked lignin structure in wood. Repression of CCoAOMT expression also led to coloration of wood and an elevation of wall-bound p-hydroxybenzoic acid. Taken together, these results indicate that CCoAOMT plays a dominant role in the methylation of the 3-hydroxyl group of caffeoyl CoA, and the CCoAOMT-mediated methylation reaction is essential to channel substrates for 5-methoxylation of hydroxycinnamates. They also suggest that antisense repression of CCoAOMT is an efficient means for genetic engineering of trees with low lignin content.

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Section: Ccoaomt Is An Ideal Target For Genetic Manipulation Of Lignimentioning

confidence: 95%

Essential Role of Caffeoyl Coenzyme A O-Methyltransferase in Lignin Biosynthesis in Woody Poplar Plants

et al. 2000

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“…Moreover, the combination of distinct substrate preferences with differences in gene-promoter and protein fine structure may facilitate not only a large diversity of genetically programmed metabolic functions of the individual isoenzymes, including pathway-specific associations with biosynthetically related enzymes in metabolite channeling (37-39), but also regular or potential functional overlaps or mutual replacements upon malfunction or down-regulation, as has been investigated so far only for the class I isoforms (4,40,41).…”

Section: Discussionmentioning

confidence: 99%

The 4-coumarate:CoA ligase gene family in Arabidopsis thaliana comprises one rare, sinapate-activating and three commonly occurring isoenzymes

Hamberger

Hahlbrock

2004

Proc. Natl. Acad. Sci. U.S.A.

224

208

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.12) has a pivotal role in the biosynthesis of plant secondary compounds at the divergence point from general phenylpropanoid metabolism to several major branch pathways. In Arabidopsis thaliana, we have identified a previously undetected, fourth and final member of the At4CL gene family. The encoded enzyme, At4CL4, exhibits the rare property of efficiently activating sinapate, besides the usual 4CL substrates (4-coumarate, caffeate, and ferulate), indicating a distinct metabolic function. Phylogenetic analysis suggests an early evolutionary and functional divergence of three of the four gene family members, At4CL2-4, whereas At4CL1 appears to have originated much later by duplication of its structurally and functionally closest relative, At4CL2. Various characteristics shared by all known plant 4CL genes, as well as by the encoded proteins, define and delimit the At4CL gene family and distinguish it from the closely related family of ''At4CL-like'' genes.

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“…Our results indicate that TK has a remarkably high flux control coefficient (Ͼ0.7) for phenylpropanoid metabolism. This is similar to or larger than the effects of the decreased expression of phenylalanine ammonia-lyase (Bate et al, 1994;Howles et al, 1996;Sewalt et al, 1997), 4-coumarate:CoA lyase (Lee et al, 1997), and cinnamate-4-hydroxylase (Sewalt et al, 1997), three enzymes that build a regulatory unit that responds to a range of developmental and environmental factors (Chapple and Carpita, 1998;Koopman et al, 1999).…”

Section: A Small Decrease In Tk Expression Leads To Lower Levels Of Amentioning

confidence: 98%

A Small Decrease of Plastid Transketolase Activity in Antisense Tobacco Transformants Has Dramatic Effects on Photosynthesis and Phenylpropanoid Metabolism

Henkes¹,

Sonnewald²,

Badur³

et al. 2001

The Plant Cell

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Transketolase (TK) catalyzes reactions in the Calvin cycle and the oxidative pentose phosphate pathway (OPPP) and produces erythrose-4-phosphate, which is a precursor for the shikimate pathway leading to phenylpropanoid metabolism. To investigate the consequences of decreased TK expression for primary and secondary metabolism, we transformed tobacco with a construct containing an antisense TK sequence. The results were as follows: (1) a 20 to 40% reduction of TK activity inhibited ribulose-1,5-bisphosphate regeneration and photosynthesis. The inhibition of photosynthesis became greater as irradiance increased across the range experienced in growth conditions (170 to 700 mol m Ϫ 2 sec Ϫ 1 ). TK almost completely limited the maximum rate of photosynthesis in saturating light and saturating CO 2 . (2) Decreased expression of TK led to a preferential decrease of sugars, whereas starch remained high until photosynthesis was strongly inhibited. One of the substrates of TK (fructose-6-phosphate) is the starting point for starch synthesis, and one of the products (erythrose-4-phosphate) inhibits phosphoglucose isomerase, which catalyzes the first reaction leading to starch. (3) A 20 to 50% decrease of TK activity led to decreased levels of aromatic amino acids and decreased levels of the intermediates (caffeic acid and hydroxycinnamic acids) and products (chlorogenic acid, tocopherol, and lignin) of phenylpropanoid metabolism. (4) There was local loss of chlorophyll and carotene on the midrib when TK activity was inhibited by Ͼ 50%, spreading onto minor veins and lamina in severely affected transformants. (5) OPPP activity was not strongly inhibited by decreased TK activity. These results identify TK activity as an important determinant of photosynthetic and phenylpropanoid metabolism and show that the provision of precursors by primary metabolism colimits flux into the shikimate pathway and phenylpropanoid metabolism. INTRODUCTIONThe interaction between primary and secondary pathways is an important but poorly understood aspect of plant metabolism. Phenylpropanoids represent an important class of secondary metabolites, with roles in plant structure, defense, and signaling (Dixon and Paiva, 1995). They are derived from aromatic amino acids, which are synthesized via the shikimate pathway in the plastid. Up to 20% of the total carbon in a plant passes through this pathway (Jensen, 1985). Even though there have been numerous studies of transformants with altered expression of genes that encode enzymes in the Calvin cycle, glycolysis, the tricarboxylic acid cycle, and the oxidative pentose phosphate pathway (OPPP) (Stitt and Sonnewald, 1995;Stitt, 1999), the consequences for phenylpropanoid metabolism or other secondary pathways have not been explored. The presence of redundant enzymes and pathways for carbohydrate breakdown and glycolysis (Dennis, 1987; Dennis et al., 1997;Stitt, 1998) and the absence of marked phenotypic changes after alterations in the expression of key enzymes, including phosphofructokinase (Burrell et...

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Antisense Suppression of 4-Coumarate:Coenzyme A Ligase Activity in Arabidopsis Leads to Altered Lignin Subunit Composition

Cited by 57 publications

References 0 publications

Essential Role of Caffeoyl Coenzyme A O-Methyltransferase in Lignin Biosynthesis in Woody Poplar Plants

Essential Role of Caffeoyl Coenzyme A O-Methyltransferase in Lignin Biosynthesis in Woody Poplar Plants

The 4-coumarate:CoA ligase gene family in Arabidopsis thaliana comprises one rare, sinapate-activating and three commonly occurring isoenzymes

A Small Decrease of Plastid Transketolase Activity in Antisense Tobacco Transformants Has Dramatic Effects on Photosynthesis and Phenylpropanoid Metabolism

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