Stress Responses in Alfalfa (Medicago sativa L.) (XIV. Changes in the Levels of Phenylpropanoid Pathway Intermediates in Relation to Regulation of L-Phenylalanine Ammonia-Lyase in Elicitor-Treated Cell-Suspension Cultures)

Orr, John D.; Edwards, Robert; Dixon, Richard A.

doi:10.1104/pp.101.3.847

Cited by 44 publications

(26 citation statements)

References 26 publications

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“…In tomato, the activation of genes encoding enzymes of the prechorismate pathway and of PAL genes by elicitor seems to be independent of changes in phenylalanine concentration. It had previously been shown that the addition of L-a-aminooxyf3-phenylpropionic acid (another PAL inhibitor) or of phenylpropanoid metabolites to elicitor-treated, cultured alfalfa cells did have an effect on the expression of the PAL genes (31). These seemingly conflicting results in the two different systems, with two different inhibitors, require further investigation.…”

Section: Resultsmentioning

confidence: 98%

Temporally distinct accumulation of transcripts encoding enzymes of the prechorismate pathway in elicitor-treated, cultured tomato cells.

Görlach

Raesecke

Rentsch

et al. 1995

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

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The accumulation of phenylalanine-derived phenolic compounds is a well-known element of a plant's defense in response to pathogen attack Phenylalanine, as well as the other two aromatic amino acids, tyrosine and tryptophan, is synthesized by way of the shikimate pathway. The first seven steps of the shikimate pathway (the prechorismate pathway) are common for the biosynthesis of all three aromatic amino acids. We have studied transcript levels of six genes-i.e., two 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase genes, one shikimate kinase gene, one 5-enolpyruvylshikimate 3-phosphate synthase gene, and two chorismate synthase genes-corresponding to four steps of the prechorismate pathway, in cultured tomato cells exposed to fungal elicitors.

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Section: Resultsmentioning

confidence: 98%

Temporally distinct accumulation of transcripts encoding enzymes of the prechorismate pathway in elicitor-treated, cultured tomato cells.

Görlach

Raesecke

Rentsch

et al. 1995

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

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“…Exogenously applied cinnamic acid at concentrations of 15 to 100 p~ is shown to be able to interfere with the 4CL enzyme activity in normal xylem, resulting in changes in its catalytic specificity toward caffeic acid in a manner similar to that in compression wood xylem (Table I). It has been estimated that the endogenous concentrations of free cinnamic acid in bean and alfalfa cell cultures are 4 to 25 and 5 to 30 p~, respectively (Mavandad et al, 1990;Loake et al, 1991;Orr et al, 1993). Although the actual pool sizes of cinnamic acid in normal and compression wood of loblolly pine are currently unknown, the levels (15-100 p~) of cinnamic acid used in the enzyme assays (Table I) expression within the phenylpropanoid pathway (Bolwell e t al., 1988;Mavandad et al, 1990;Loake et al, 1991Loake et al, , 1992Orr et al, 1993;Ni et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

Molecular Cloning of 4-Coumarate:Coenzyme A Ligase in Loblolly Pine and the Roles of This Enzyme in the Biosynthesis of Lignin in Compression Wood

1997

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Two genomic sequences encoding 4-coumarate:coenzyme A ligase (4CL; EC 6.2.1.1 2) in loblolly pine (Pinus faeda 1.) were cloned. Both sequences contained three introns and four exons with identical coding sequences predicting 537 amino acids. Two of the three introns in these two clones were different both in sequence and in length. Sequences of both 4CL clones were found in all nine megagametophyte DNAs tested, providing genetic evidence that these two 4CL genomic sequences are nonallelic genes. Our analyses suggest that there are at least two distinct, intron-containing 4CL genes, at least one of which is transcribed into 4CL mRNA in developing xylem tissue of loblolly pine. The levels of 4CL gene transcription in xylem were influenced by compressional stress, resulting in an elevated 4CL enzyme activity with 4-coumaric acid. 4CL enzyme activity with ferulic acid remained unchanged, whereas with caffeic acid it was significantly inhibited. Exogenously applied trans-cinnamic acid in the protein extracts from normal wood xylem caused inhibition of 4CL activity toward caffeic acid similar to that under compressional stress. The implications of this cinnamic acid-modulated effect on 4CL enzyme activities toward different substrates in regulating monolignol synthesis in xylem under compressional stress are discussed.

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“…More recent studies have documented increases in C4H mRNA abundance in response to some of the same factors (Fahrendorf and Dixon, 1993;Buell and Somerville, 1995;Logemann et al, 1995). In addition, C4H activity is modulated in response to the application of exogenous p-coumaric acid (Lamb and Rubery, 1976), suggesting that the endogenous pools of phenylpropanoid intermediates may play an important role in the regulation of C4H gene expression, as has been documented for other genes in this pathway (Bolwell et al, 1988;Loake et al, 1992;Orr et al, 1993). Plant Physiol.…”

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confidence: 84%

Cinnamate-4-Hydroxylase Expression in Arabidopsis (Regulation in Response to Development and the Environment)

et al. 1997

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Cinnamate-4-hydroxylase (C4H) is the first Cyt P450-dependent monooxygenase of the phenylpropanoid pathway. To study the expression of this gene in Arabidopsis thaliana, a C 4 H cDNA clone from the Arabidopsis expressed sequence tag database was identified and used to isolate its corresponding genomic clone. The entire C4H coding sequence plus 2.9 kb of its promoter were isolated on a 5.4-kb Hindlll fragment of this cosmid. lnspection of the promoter sequence revealed the presence of a number of putative regulatory motifs previously identified in the promoters of other phenylpropanoid pathway genes. The expression of C4H was analyzed by RNA blot hybridization analysis and in transgenic Arabidopsis carrying a C4H-P-glucuronidase transcriptional fusion. C4H message accumulation was light-dependent, but was detectable even in dark-grown seedlings. Consistent with these data, C4H mRNA was accumulated to light-grown levels in etiolated detl-7 mutant seedlings. C4H is widely expressed in various Arabidopsis tissues, particularly in roots and cells undergoing lignification. The C4H-driven /3-glucuronidase expression accurately reflected the tissue-specificity and woundinducibility of the C4H promoter indicated by RNA blot hybridization analysis. A modest increase in C4H expression was observed in the tt8 mutant of Arabidopsis.The phenylpropanoid pathway gives rise to a wide array of metabolites. These compounds participate in many plantdefense responses (Nicholson and Hammerschmidt, 1992) and absorb potentially damaging UV-B radiation (Caldwell et al., 1983;Li et al., 1993;Landry et al., 1995). The pathway also generates the monomers required for lignin biosynthesis: ferulic acid and sinapic acid (Lewis and Yamamoto, 1990). The purification of the soluble enzymes of the phenylpropanoid pathway over the last 10 years has permitted the cloning of their respective genes. These include the genes encoding Phe ammonia-lyase, p-coumarate COA ligase, caffeic acidl5-hydroxyferulic acid, O-methyltransferase, chalcone synthase, and chalcone isomerase. In comparison, the genes encoding two of the Cyt P450-dependent monooxygenases (P450s) in this pathway, C4H and ferulate-5-

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Stress Responses in Alfalfa (Medicago sativa L.) (XIV. Changes in the Levels of Phenylpropanoid Pathway Intermediates in Relation to Regulation of L-Phenylalanine Ammonia-Lyase in Elicitor-Treated Cell-Suspension Cultures)

Cited by 44 publications

References 26 publications

Temporally distinct accumulation of transcripts encoding enzymes of the prechorismate pathway in elicitor-treated, cultured tomato cells.

Temporally distinct accumulation of transcripts encoding enzymes of the prechorismate pathway in elicitor-treated, cultured tomato cells.

Molecular Cloning of 4-Coumarate:Coenzyme A Ligase in Loblolly Pine and the Roles of This Enzyme in the Biosynthesis of Lignin in Compression Wood

Cinnamate-4-Hydroxylase Expression in Arabidopsis (Regulation in Response to Development and the Environment)

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