Over-expression of cinnamate 4-hydroxylase leads to increased accumulation of acetosyringone in elicited tobacco cell-suspension cultures

Blount, Jack W.; Masoud, Sameer; Sumner, Lloyd W.; Huhman, David V.; Dixon, Richard A.

doi:10.1007/s00425-001-0701-5

Cited by 32 publications

(16 citation statements)

References 43 publications

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“…A cell culture derived from over-expression lines displayed few metabolic phenotypes. Upon treatment with a fungal elicitor, accumulation of most phenylpropanoids (including chlorogenic acid) remained unaltered, but higher levels of acetosyringone, a likely derivative of sinapate, was found to over-accumulate (Blount et al 2002). Likewise, overexpression of the alfalfa C4H in tobacco, resulting in a twofold activity increase, had no effect on lignin composition, while down-regulation (more than twofold lower activity) resulted in reduced total Klason lignin (Sewalt et al 1997).…”

Section: Regulationmentioning

confidence: 89%

Cytochromes P450 in phenolic metabolism

et al. 2006

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Three independent cytochrome P450 enzyme families catalyze the three rate-limiting hydroxylation steps in the phenylpropanoid pathway leading to the biosynthesis of lignin and numerous other phenolic compounds in plants. Their characterization at the molecular and enzymatic level has revealed an unexpected complexity of phenolic metabolism as the major route involves shikimate/quinate esters and alcohol/ aldehyde intermediates. Engineering expression of CYP73s (encoding cinnamate 4-hydroxyl ase), CYP98s (encoding 4-coumaroylshikimate 3¢-hydroxylase) or CYP84s (encoding coniferaldehyde 5-hydroxylase) leads to modified lignin and seed phenolic composition. In particular CYP73s and CYP98s also play essential roles in plant growth and development, while CYP84 constitutes a check-point for the synthesis of syringyl lignin and sinapate esters. Although recent data shed new light on the main path for lignin synthesis, they also raised new questions. Mutants and engineered plants revealed the existence of (an) alternative pathway(s), which most likely involve(s) different precursors and oxygenases. On the other hand, phylogenetic analysis of plant genomes show the existence of P450 gene duplications in each family, which may have led to the acquisition of novel or additional physiological functions in planta. In addition to the main lignin pathway, P450s contribute to the biosynthesis of many bioactive phenolic derivatives, with potential applications in medicine and plant defense, including lignans, phenylethanoids, benzoic acids, xanthones or quinoid compounds. A very small proportion of these P450s have been characterized so far, and rarely at a molecular level. The possible involvement of P450s in salicylic acid is discussed.Keywords Cytochrome P450 monooxygenases Á Phenylpropanoid metabolism Á Cinnamate 4-hydroxylase Á C4H Á Coumaroyl-shikimate 3¢-hydroxylase Á C3¢H Á Coniferaldehyde 5-hydroxylase Á CA5H Á F5H Á Lignin Á Sinapate esters Á Rosmarinic acid Á Salicylic acid Á Benzoic acid Á Podophyllotoxin Á Xanthone

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Section: Regulationmentioning

confidence: 89%

Cytochromes P450 in phenolic metabolism

et al. 2006

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“…Compounds were monitored with a diode array detector at 310, 287, 270 and 254 nm. The wall-bound phenolics were released from the cell residues that had been extracted for soluble phenolics as previously described (Blount et al 2002) and analyzed by HPLC as above. Samples were applied to an ODS2 reverse-phase column (J.T.…”

Section: Extraction and Hplc Analysis Of Phenolic Compoundsmentioning

confidence: 99%

Methyl jasmonate and yeast elicitor induce differential transcriptional and metabolic re-programming in cell suspension cultures of the model legume Medicago truncatula

Suzuki

Reddy

Naoumkina

et al. 2004

Planta

175

139

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Exposure of cell suspension cultures of Medicago truncatula Gaerth. to methyl jasmonate (MeJA) resulted in up to 50-fold induction of transcripts encoding the key triterpene biosynthetic enzyme beta-amyrin synthase (betaAS; EC 5.4.99.-). Transcripts reached maximum levels at 24 h post-elicitation with 0.5 mM MeJA. The entry point enzymes into the phenylpropanoid and flavonoid pathways, L: -phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) and chalcone synthase (CHS; EC 2.3.1.74), respectively, were not induced by MeJA. In contrast, exposure of cells to yeast elicitor (YE) resulted in up to 45- and 14-fold induction of PAL and CHS transcripts, respectively, at only 2 h post-elicitation. betaAS transcripts were weakly induced at 12 h after exposure to YE. Over 30 different triterpene saponins were identified in the cultures, many of which were strongly induced by MeJA, but not by YE. In contrast, cinnamic acids, benzoic acids and isoflavone-derived compounds accumulated following exposure of cultures to YE, but few changes in phenylpropanoid levels were observed in response to MeJA. DNA microarray analysis confirmed the strong differential transcriptional re-programming of the cell cultures for multiple genes in the phenylpropanoid and triterpene pathways in response to MeJA and YE, and indicated different responses of individual members of gene families. This work establishes Medicago cell cultures as an excellent model for future genomics approaches to understand the regulation of legume secondary metabolism.

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“…Bacterial virulence (vir) gene induction was reduced in the COMT-suppressed line likely due to the highly reduced level of the phenolic elicitor of Agrobacterium acetosyringone (Maury et al, 2010). Acetosyringone is probably derived from Coenzyme A dependent β-oxidation of hydroxycinnamoyl-CoA intermediates of monolignol biosynthesis (Blount et al, 2002; Negrel and Javelle, 2010). In Arabidopsis and tobacco, the alteration to phenylpropanoid metabolism by reducing COMT activity appears to directly result in increased resistance to two of the pathogens tested, downy mildew and Agrobacterium , respectively.…”

Section: Caffeic O-methyltransferasementioning

confidence: 99%

Modifying lignin to improve bioenergy feedstocks: strengthening the barrier against pathogens?†

Sattler¹,

2013

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Lignin is a ubiquitous polymer present in cell walls of all vascular plants, where it rigidifies and strengthens the cell wall structure through covalent cross-linkages to cell wall polysaccharides. The presence of lignin makes the cell wall recalcitrant to conversion into fermentable sugars for bioenergy uses. Therefore, reducing lignin content and modifying its linkages have become major targets for bioenergy feedstock development through either biotechnology or traditional plant breeding. In addition, lignin synthesis has long been implicated as an important plant defense mechanism against pathogens, because lignin synthesis is often induced at the site of pathogen attack. This article explores the impact of lignin modifications on the susceptibility of a range of plant species to their associated pathogens, and the implications for development of feedstocks for the second-generation biofuels industry. Surprisingly, there are some instances where plants modified in lignin synthesis may display increased resistance to associated pathogens, which is explored in this article.

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Over-expression of cinnamate 4-hydroxylase leads to increased accumulation of acetosyringone in elicited tobacco cell-suspension cultures

Cited by 32 publications

References 43 publications

Cytochromes P450 in phenolic metabolism

Cytochromes P450 in phenolic metabolism

Methyl jasmonate and yeast elicitor induce differential transcriptional and metabolic re-programming in cell suspension cultures of the model legume Medicago truncatula

Modifying lignin to improve bioenergy feedstocks: strengthening the barrier against pathogens?†

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