Regulation of Enzymes Involved in Lignin Biosynthesis: Induction of<i>O</i>-Methyltransferase mRNAs During the Hypersensitive Reaction of Tobacco to Tobacco Mosaic Virus

Jaeck, Estelle; Dumas, Bernard; Geoffroy, Philippe; Favet, Noelle; Inzé, Dirk; Montagu, M. van; Fritig, Bernard; Legrand, Michel

doi:10.1094/mpmi-5-294

Cited by 82 publications

(58 citation statements)

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“…Lignin is composed of phenylpropanol units (monolignols) oxidatively coupled through ether and carbon-carbon linkages. This natural polymer can function as a genetically inducible physical barrier in response to microbial attack [4,23,27,39,49]. In addition to structural support and pathogen defense, lignin functions in water transport as a hydrophobic constituent of vascular phloem and xylem cells [26,56].…”

Section: Lignin Lignans and Phenylpropenesmentioning

confidence: 99%

Structure and function of enzymes involved in the biosynthesis of phenylpropanoids

Ferrer

Austin

Stewart

et al. 2008

Plant Physiology and Biochemistry

681

413

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As a major component of plant specialized metabolism, phenylpropanoid biosynthetic pathways provide anthocyanins for pigmentation, flavonoids such as flavones for protection against UV photodamage, various flavonoid and isoflavonoid inducers of Rhizobium nodulation genes, polymeric lignin for structural support and assorted antimicrobial phytoalexins. As constituents of plant-rich diets and an assortment of herbal medicinal agents, the phenylpropanoids exhibit measurable cancer chemopreventive, antimitotic, estrogenic, antimalarial, antioxidant and antiasthmatic activities. The health benefits of consuming red wine, which contains significant amounts of 3,4′,5-trihydroxystilbene (resveratrol) and other phenylpropanoids, highlight the increasing awareness in the medical community and the public at large as to the potential dietary importance of these plant derived compounds. As recently as a decade ago, little was known about the three-dimensional structure of the enzymes involved in these highly branched biosynthetic pathways. Ten years ago, we initiated X-ray crystallographic analyses of key enzymes of this pathway, complemented by biochemical and enzyme engineering studies. We first investigated chalcone synthase (CHS), the entry point of the flavonoid pathway, and its close relative stilbene synthase (STS). Work soon followed on the O-methyl transferases (OMTs) involved in modifications of chalcone, isoflavonoids and metabolic precursors of lignin. More recently, our groups and others have extended the range of phenylpropanoid pathway structural investigations to include the upstream enzymes responsible for the initial recruitment of phenylalanine and tyrosine, as well as a number of reductases, acyltransferases and ancillary tailoring enzymes of phenylpropanoid-derived metabolites. These structure-function studies collectively provide a comprehensive view of an important aspect of phenylpropanoid metabolism. More specifically, these atomic resolution insights into the architecture and mechanistic underpinnings of phenylpropanoid metabolizing enzymes contribute to our understanding of the emergence and ongoing evolution of specialized phenylpropanoid products, and underscore the molecular basis of metabolic biodiversity at the chemical level. Finally, the detailed knowledge of the structure, function and evolution of these enzymes of specialized metabolism provide a set of experimental templates for the enzyme and metabolic engineering of production platforms for diverse novel compounds with desirable dietary and medicinal properties.

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Section: Lignin Lignans and Phenylpropenesmentioning

confidence: 99%

Structure and function of enzymes involved in the biosynthesis of phenylpropanoids

Ferrer

Austin

Stewart

et al. 2008

Plant Physiology and Biochemistry

681

413

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“…They include the NADP-dependent malic enzyme and pyruvate decarboxylase (PDC), caffeic acid 3-o-methyltransferase, and putative isoflavone reductase. These proteins are enzymes involved in the lignin and phytoalexin biosynthesis of the phenylpropanoid pathway and known to be highly induced after infection of pathogens (Dumas et al, 1988;Jaeck et al, 1992;Pellegrini et al, 1993Pellegrini et al, , 1994. We have recently found that PAL transcripts were decreased in rice cell cultures in which OsMAPK6 expression was silenced by RNAi (Lieberherr et al, 2005).…”

Section: Phenylpropanoid Biosynthesis Pathwaymentioning

confidence: 99%

Proteomics of Rac GTPase Signaling Reveals Its Predominant Role in Elicitor-Induced Defense Response of Cultured Rice Cells

2005

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We have previously shown that a human small GTPase Rac homolog, OsRac1, from rice (Oryza sativa) induces cascades of defense responses in rice plants and cultured cells. Sphingolipid elicitors (SEs) have been similarly shown to activate defense responses in rice. Therefore, to systematically analyze proteins whose expression levels are altered by OsRac1 and/or SE treatment, we performed a differential display analysis of proteins by the use of two-dimensional gel electrophoresis and mass spectrometry. A total of 271 proteins whose expression levels were altered by constitutively active (CA)-OsRac1 or SE were identified. Interestingly, of 100 proteins that were up-regulated by a SE, 87 were also induced by CA-OsRac1, suggesting that OsRac1 plays a pivotal role in defense responses induced by SE in cultured rice cells. In addition, CA-OsRac1 induces the expression of 119 proteins. Many proteins, such as pathogenesis-related proteins, SGT1, and prohibitin, which are known to be involved in the defense response, were found among these proteins. Proteins involved in redox regulation, chaperones such as heat shock proteins, BiP, and chaperonin 60, proteases and protease inhibitors, cytoskeletal proteins, subunits of proteasomes, and enzymes involved in the phenylpropanoid and ethylene biosynthesis pathways were found to be induced by CA-OsRac1 or SE. Results of our proteomic analysis revealed that OsRac1 is able to induce many proteins in various signaling and metabolic pathways and plays a predominant role in the defense response in cultured rice cells.

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“…COMT and CCOMT introduce the first methoxy group into the aromatic rings of hydroxycinnamic acids and monolignols, and have been implicated in the biosynthesis of wallbound phenolic compounds in plant cells (Maule and Ride, 1976;Pakusch et al, 1989;Jaeck et al, 1992). The transcription of their corresponding genes is strongly activated in alfalfa cell cultures in response to an elicitor from yeast cell walls, to a similar or greater extent than that of PAL, the first enzyme of the phenylpropanoid pathway.…”

Section: Conclusion: Control Points For the Selectivity Of Elicitor-mmentioning

confidence: 99%

Stress Responses in Alfalfa (XXI. Activation of Caffeic Acid 3-O-Methyltransferase and Caffeoyl Coenzyme A 3-O-Methyltransferase Genes Does Not Contribute to Changes in Metabolite Accumulation in Elicitor-Treated Cell-Suspension Cultures)

Sewalt

Korth

et al. 1996

Plant Physiology

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Transcription of genes encoding i-phenylalanine ammonia-lyase (PAL), the first enzyme of the phenylpropanoid pathway, and caffeic acid 3-Omethyltransferase (COMT) and caffeoyl COA 3 -0 methyltransferase (CCOMT), enzymes involved in the synthesis of lignin and wall-esterified phenolic compounds, was strongly activated in elicitor-treated cell-suspension cultures of alfalfa (Medicago safiva 1.). However, consequent changes in the extractable activities of COM1 and CCOMT were small to nonexistent compared with a 15-to 16-fold increase in PAL activity. Only low levels of COMT and CCOMT transcripts were reflected in the total and polysomal RNA fractions compared with PAL transcripts. Elicited cell cultures did not accumulate lignin or the products of COM1 and CCOMT in the soluble and wall-esterified phenolic fractions. In one alfalfa cell line in which elicitation resulted in very high PAL activity and increased deposition of methoxyl groups in the insoluble wall fraction, there was still no change in COM1 and CCOMT activities. Overall, these results indicate that the initial gene transcription events in elicited cells may be less selective than the subsequent metabolic changes, highlighting the importance of posttranscriptional events in the control of phenylpropanoid biosynthesis.

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Regulation of Enzymes Involved in Lignin Biosynthesis: Induction ofO-Methyltransferase mRNAs During the Hypersensitive Reaction of Tobacco to Tobacco Mosaic Virus

Cited by 82 publications

References 0 publications

Structure and function of enzymes involved in the biosynthesis of phenylpropanoids

Structure and function of enzymes involved in the biosynthesis of phenylpropanoids

Proteomics of Rac GTPase Signaling Reveals Its Predominant Role in Elicitor-Induced Defense Response of Cultured Rice Cells

Stress Responses in Alfalfa (XXI. Activation of Caffeic Acid 3-O-Methyltransferase and Caffeoyl Coenzyme A 3-O-Methyltransferase Genes Does Not Contribute to Changes in Metabolite Accumulation in Elicitor-Treated Cell-Suspension Cultures)

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