Stimulation of Phenylalanine Ammonia-Lyase Activity and Phytoalexin Production

Hadwiger, Lee A.; Hess, Samuel L.; Broembsen, S. Von

doi:10.1094/phyto-60-332

Cited by 56 publications

(12 citation statements)

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“…There is reason to believe that numerous polypeptide components remain to be discovered which can influence plant cell processes (46). Phytoalexin induction in pea tissue has been employed as one measure of the effects of chemically defined compounds on the regulation of cell processes (12,(15)(16)(17)(18)(19)(20)(21)38). We now report that basic peptides can induce gene-controlled responses, and we demonstrate that this gene-activating potential exists for basic compounds (2,41,47) which occur in plants and other higher organisms.…”

mentioning

confidence: 70%

Mode of Pisatin Induction

Hadwiger¹,

Jafri²,

Broembsen³

et al. 1974

Plant Physiol.

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Increases in phenylalanine ammonia lyase activity and pisatin synthesis were induced in excised pea pods (a) by basic polypeptides such as protamine, histone, lysozyme, cytochrome c, and ribonuclease; (b) by the polyamines spermine, spermidine, cadaverine, and putrescine, and (c) by the synthetic oligopeptides poly-L-lysine, poly-DL-ornithine, and poly-Poly-L-lysine (1 milligram per milliliter, molecular weight 7,200) was utilized as a model inducer of pisatin and phenylalanine ammonia lyase. The poly-L-lysine-induced responses could be inhibited by adding the RNA synthesis inhibitors cordycepin or a-amanitin to the pods prior to or at the time of inducer application. Cordycepin added 1.5 hours after inducer no longer completely inhibited induction. The application of poly-L-lysine was shown to characteristically change the rate of RNA synthesis within 30 minutes. Ultrastructural changes in pea nuclei were detected within 3 hours, and gross changes in nuclear morphology were apparent at 14 hours after inducer application. The physical appearance of uranyl acetate-stained chromatin isolated from poly-L-lysine 2 hours after inducer application differed from that of water-treated tissues. The template properties of chromatin extracted from pods 3 hours after inducer application were consistently superior to control chromatin when assayed with Escherichia coli RNA polymerase (without sigma factor). Chromatin from poly-L-lysine-induced tissue also bound 49% more actinomycin D-'H.The DNA-complexing properties of inducer compounds and the induced changes in the template and dye-binding properties of pea chromatin formed the basis for a proposed mode of action for phytoalexin induction.The functions of numerous polypeptide hormones (5) have been characterized in animal systems; however, interest in the potential role of polypeptides in regulating plant processes is still limited. There is reason to believe that numerous polypeptide components remain to be discovered which can influence plant cell processes (46). Phytoalexin induction in pea tissue has been employed as one measure of the effects of chemically defined compounds on the regulation of cell processes (12,(15)(16)(17)(18)(19)(20)(21)38). We now report that basic peptides can induce gene-controlled responses, and we demonstrate that this gene-activating potential exists for basic compounds (2, 41, 47) which occur in plants and other higher organisms.The synthetic compound, poly-L-lysine, was chosen as a model inducer because of its amino acid residue uniformity and chemical simplicity. This paper examines the phytoalexininducing effect of poly-L-lysine in relation to (a) alteration of the fine structure of nuclei and cell membranes, (b) template activity and dye-binding capacity of isolated chromatin, (c) the in vivo rate of RNA synthesis, and (d) the dependency of the induction process on RNA and protein synthesis.Our previous hypothesis (20, 38) that regulation of gene expression can occur as a result of changes in the conformation of specific segment...

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confidence: 70%

Mode of Pisatin Induction

Hadwiger¹,

Jafri²,

Broembsen³

et al. 1974

Plant Physiol.

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“…The Further, ethidium bromide and certain acridines, antibiotics, dyes, heavy metal salts, and alkylating agents have a selective effect on the DNA of subcellular organelles (8,24). Most of these compounds can also induce phytoalexin synthesis (9,19,21). In certain animal systems, it has been proposed that DNA-intercalating compounds (in the presence of steroid hormones) "super-induce" enzyme synthesis by selectively inhibiting a posttranscriptional repressor (23).…”

Section: Resultsmentioning

confidence: 99%

“…Similar compounds, all DNA intercalators, having dimethylamino, diethylamino, amino, or 9-alkylamino substitutions of a three-ring acridine skeleton, are also inducers of phenylalanine ammonia lyase and phaseollin synthesis. It is suggested that 9-aminoacridine and other DNA intercalators function as inducers of phaseollin and phenylalanine ammonia lyase synthesis by reacting with the DNA template.Bean pod tissue produces phaseollin, an isoflavonoid with antifungal properties, when challenged by various microorganisms or treated with a wide variety of chemicals (5,7,9,12,18). Phaseollin is not detectable in untreated tissue (11).…”

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The Induction of Phenylalanine Ammonia Lyase and Phaseollin by 9-Aminoacridine and Other Deoxyribonucleic Acid Intercalating Compounds

Hess

Hadwiger

1971

Plant Physiol.

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Bean pod tissue (Phaseolus vulgaris L. var. Top Crop) is induced to produce phaseollin when challenged with various microorganisms. The pods react in the same manner when challenged with 9-aminoacridine. This compound also caused an increase in concentrations of phenylalanine ammonia lyase, an enzyme of the phaseollin synthesizing pathway. Both the synthesis of phenylalanine ammonia lyase and phaseollin are subject to inhibition by actinomycin D, cycloheximide, or 6-methylpurine. The results suggest that both phaseollin production and increased phenylalanine ammonia lyase, when induced by 9-aminoacridine, require newly synthesized RNA and protein.The concentration of 9-aminoacridine optimal for synthesis of phaseollin and PAL (0.5 mg/ml) does not increase the rate of total protein synthesis. However, there is a differential effect of 9-aminoacridine on synthesis of certain protein fractions.Optimal concentrations of 9-aminoacridine induce phaseollin and phenylalanine ammonia lyase synthesis while reducing the net synthesis of RNA during the period of induction.The planar three-ring structure of 9-aminoacridine appears to be a desirable feature for phaseollin and phenylalanine ammonia lyase induction. Similar compounds, all DNA intercalators, having dimethylamino, diethylamino, amino, or 9-alkylamino substitutions of a three-ring acridine skeleton, are also inducers of phenylalanine ammonia lyase and phaseollin synthesis. It is suggested that 9-aminoacridine and other DNA intercalators function as inducers of phaseollin and phenylalanine ammonia lyase synthesis by reacting with the DNA template.Bean pod tissue produces phaseollin, an isoflavonoid with antifungal properties, when challenged by various microorganisms or treated with a wide variety of chemicals (5,7,9,12,18). Phaseollin is not detectable in untreated tissue (11). The induced production of phaseollin in infected bean tissue provides a level of defense against certain fungal pathogens (6, 18). The mechanism of its induction is of interest in understanding disease resistance responses in plants. ' This paper reports that 9-aminoacridine, and a number of other similar compounds, can induce the formation of phaseollin and/or phenylalanine ammonia lyase (PAL)3, E.C. 4.3.1.5 (a key enzyme in the biosynthesis of phaseollin [11]) in excised bean pods. Changes in RNA and protein synthesis which occur subsequent to the application of 9-aminoacridine are also described. MATERIALS AND METHODS Plant Materials. Bean plants (Phaseolus vulgaris L. var.Top Crop) were grown in sand. Fresh pods, 3 to 5 cm in length, were excised and split lengthwise in three 1 to 2 mm slices, spread evenly over the bottom of a Petri dish, and then treated as described below.Phenylalanine Ammonia Lyase. After designated incubation periods in the dark, 1-g samples of pods were homogenized and assayed for PAL. The assay mixture contained 1.8 ml of homogenate, 0.2 ml of borate buffer, pH 8.8, 20 ,umoles of L-phenylalanine, and 0.125 btC of L-phenylalanine-U-14C(265 mc/mmole). The r...

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“…An antifungal substance, orchinol, is formed in tubers of Orchis mititaris in response to infection (Nuesch, 1963). Orchinol is a phenolic compound the chemical structure of which is related to many phytoalexins; it may therefore be formed from phenylalanine as a result of the action of phenylalanine ammonia lyase (Hadwiger, Hess and Broembsen, 1970). An investigation of changes in activity of this enzyme as a result of mycorrhizal infection might provide a more direct link with processes associated with defence in orchids.…”

Section: Discussionmentioning

confidence: 99%

Effect of Mycorrhizal Infection on Respiration and Activity of Some Oxidase Enzymes of Orchid Protocorms

1976

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Summary Infection of protocorms of Dactylorhiza purpurella and a Cymbidium hybrid by an endophytic mycorrhizal fungus (Rhizoctonia sp.) led to a marked stimulation of respiration. Peak oxygen uptake often coincided with formation and digestion of pelotons. Treatment of protocorms with culture filtrates or mycelial extracts of the mycorrhizal fungus also enhanced oxygen uptake. Activities of polyphenol oxidase, ascorbic acid oxidase, peroxidase and catalase were greatly increased in infected protocorms. Peak activity often coincided with peak oxygen uptake and digestion of pelotons, except for peroxidase where peak activity occurred earlier. The orchid/endophyte system is compared with host/pathogen interactions in terms of the possible relationship between changes in enzyme activity and defence mechanisms.

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Stimulation of Phenylalanine Ammonia-Lyase Activity and Phytoalexin Production

Cited by 56 publications

References 4 publications

Mode of Pisatin Induction

Mode of Pisatin Induction

The Induction of Phenylalanine Ammonia Lyase and Phaseollin by 9-Aminoacridine and Other Deoxyribonucleic Acid Intercalating Compounds

Effect of Mycorrhizal Infection on Respiration and Activity of Some Oxidase Enzymes of Orchid Protocorms

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