Distribution of Phenylalanine Ammoma-Lyase and 4-Coumarate: CoA Ligase in Oat Primary Leaf Tissues

1981 ◽  
Vol 36 (5-6) ◽  
pp. 389-395 ◽  
Author(s):  
Wolfgang Knogge ◽  
Christa Beulen ◽  
Gottfried Weissenböck

Abstract 4-Coumarate: CoA ligase (CL) isolated from oat primary leaves shows two activity maxim a in 5 and 7 day old seedlings, the first of which corresponds with the highest flavone accumulation rate. In this plant stage most of L-phenylalanine ammonia-lyase (PAL) is located in the epidermal tissues, whereas CL dominates in mesophyll protoplasts and in the vascular elements. In the older leaves, in which PAL is only detectable in the epiderm is and in vascular elements, most of CL is located in the latter. The CL from different tissues varies significantly in substrate specificity. Investigations of intact chloroplasts from isolated protoplasts revealed that approximately half of the PAL activity can be extracted from this organelle, whereas there is no direct evidence for the existence of CL in plastids.

2010 ◽  
Vol 56 (No. 11) ◽  
pp. 508-515 ◽  
Author(s):  
G. Zheng ◽  
H.P. Lv ◽  
S. Gao ◽  
S.R. Wang

In the present study, Glycyrrhiza uralensis (Leguminosae) seeds were germinated and grown with different concentrations (0, 0.05, 0.1, 0.2 and 0.4 mmol/l) of cadmium acetate, in order to investigate the effects of cadmium on the growth, uptake, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in Glycyrrhiza uralensis seedlings. Uptake of Cd in different tissues of seedlings increased with increasing Cd concentrations in the tested medium, with most accumulation in the radicles. Results suggested that increased cadmium concentrations lead to decreased shoot elongation and seedling biomass. SOD activity in the cotyledons, hypocotyls and radicles increased gradually up to 0.2, 0.1 and 0.4 mmol/l, respectively. POD activity in the cotyledons, hypocotyls and radicles concentrations increased continuously with rising cadmium concentrations up to 0.2, 0.1 and 0.1 mmol/l, respectively. CAT activity in the cotyledons, hypocotyls and radicles increased gradually with increasing cadmium concentrations up to 0.2, 0.2 and 0.1 mmol/l, respectively. PPO activity showed significant increases in the cotyledons, hypocotyls and radicles at 0.4, 0.1 and 0.2 mmol/l cadmium, respectively. A significant change of PAL activity in the cotyledons, hypocotyls and radicles was observed with increasing cadmium concentrations up to 0.2, 0.4 and 0.2 mmol/l, respectively. Results of POD isoenzymes suggested that the staining intensities of isoform patterns were consistent with the changes of the activities assayed in solutions. These results suggested that Glycyrrhiza uralensis seedlings may have a better protection against oxidative stress by increasing antioxidant enzymes and PAL activity exposed to cadmium toxicity.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Sonja Gadzovska Simic ◽  
Oliver Tusevski ◽  
Stéphane Maury ◽  
Alain Delaunay ◽  
Claude Joseph ◽  
...  

The effects of polysaccharide elicitors such as chitin, pectin, and dextran on the production of phenylpropanoids (phenolics and flavonoids) and naphtodianthrones (hypericin and pseudohypericin) inHypericum perforatumshoot cultures were studied. Nonenzymatic antioxidant properties (NEAOP) and peroxidase (POD) activity were also observed in shoot extracts. The activities of phenylalanine ammonia lyase (PAL) and chalcone-flavanone isomerase (CHFI) were monitored to estimate channeling in phenylpropanoid/flavonoid pathways of elicited shoot cultures. A significant suppression of the production of total phenolics and flavonoids was observed in elicited shoots from day 14 to day 21 of postelicitation. This inhibition of phenylpropanoid production was probably due to the decrease in CHFI activity in elicited shoots. Pectin and dextran promoted accumulation of naphtodianthrones, particularly pseudohypericin, within 21 days of postelicitation. The enhanced accumulation of naphtodianthrones was positively correlated with an increase of PAL activity in elicited shoots. All tested elicitors induced NEAOP at day 7, while chitin and pectin showed increase in POD activity within the entire period of postelicitation. The POD activity was in significantly positive correlation with flavonoid and hypericin contents, suggesting a strong perturbation of the cell redox system and activation of defense responses in polysaccharide-elicitedH. perforatumshoot cultures.


Weed Science ◽  
1981 ◽  
Vol 29 (4) ◽  
pp. 433-439 ◽  
Author(s):  
Robert E. Hoagland ◽  
Stephen O. Duke

Effects of 16 herbicides representing 14 herbicide classes on growth and extractable phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) were examined in light- and dark-grown soybean [Glycine max(L.) Merr. ‘Hill’] seedlings. High purity (96 to 100%) herbicides were supplied via aqueous culture at various concentrations: 0.5 mM amitrole (3-amino-s-triazole), 0.1 mM atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], 0.07 mM diclofop-methyl {methyl ester of 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoicacid}, 0.5 mM DSMA (disodium methanearsonate), 0.2 mM fenuron (1,1-dimethyl-3-phenylurea), 0.05 mM fluridone {1-methyl-3-phenyl-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone}, 0.5 mM MH (1,2-dihydro-3,6-pyridazinedione), 0.5 mM metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one], 1.8 μM nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline], 0.5 mM norflurazon [4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone], 0.05 mM paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), 0.15 mM perfluidone {1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl)phenyl] methanesulfonamide}, 0.2 mM propanil (3′,4′-dichloropropionanilide), 0.1 mM propham (isopropyl carbanilate), 0.5 mM TCA (trichloroacetic acid), and 0.05 mM 2,4-D [(2,4-dichlorophenoxy)acetic acid]. Dark-grown soybean seedlings (3-day-old) were transferred to control solutions (2 mM CaSO4) or to herbicide solutions (in 2 mM CaSO4) and grown at 25 C in continuous white light (200 μE•m-2•s-1) or continuous darkness until harvested 24 or 48 h after transfer. After 48 h, growth (fresh weight, dry weight, elongation) was inhibited by most of the chemicals. Other signs of toxicity (necrosis, secondary root stunting, and root tip swelling) were noted for some treatments. Roots were most affected, although hypocotyls were generally not changed. Hypocotyl elongation was stimulated by atrazine, fluridone, and norflurazon after 48 h light. Extractable PAL activity from soybean axes was decreased by atrazine, fenuron, metribuzin, norflurazon, propanil, propham, and 2,4-D. Amitrole and paraquat were the only herbicides that increased extractable PAL activity. Other compounds tested had no effect on the enzyme. None of the herbicides significantly affected in vitro PAL activity.


2020 ◽  
Vol 11 (2) ◽  
pp. 124-136 ◽  
Author(s):  
Sehrish Nawaz ◽  
Asghari Bano

Background: The present investigation aimed to evaluate the role of Plant Growth- Promoting Rhizobacteria (PGPR) and Ag-nanoparticles on two varieties (American variety, Poinsett 76 and Desi variety, Sialkot selection) of cucumber plants. Methods: Cucumber seeds prior to sowing, were inoculated with two strains of PGPR, Pseudomonas putida (KX574857) and Pseudomonas stutzeri (KX574858) at the rate of 106 cells/ml. Agnanoparticles (5ppm) were sprayed on the plant at early vegetative phase 27 d after sowing. Results: The proline, sugar, protein, phenolics, flavonoids, chlorophyll and carotenoids contents of leaves of plants and the activities of Phenylalanine Ammonia-Lyase (PAL), Superoxide Dismutase (SOD) and Catalase (CAT) were determined from leaves of plants at early vegetative phase. After 3 months of seeds sowing, Ag-nanoparticles enhanced the length of root but decreased the length of shoot and fresh weight of root and shoot as compared to control whereas, the leaf protein, proline, phenolics, flavonoids, chlorophyll b, total chlorophyll, sugar and Phenylalanine Ammonia-Lyase (PAL) activity of plants were increased significantly over control. Ag-nanoparticles also suppressed the effect of PGPR for root, shoot length but augmented the protein and phenolics contents of leaves of both the varieties. Conclusion: The combined treatment of Ag-nanoparticles and PGPR enhanced flavonoids content of leaves and the activities of PAL, SOD and CAT in leaves of plants over control. Agnanoparticles effectively increased the Phenylalanine Ammonia-Lyase (PAL), Catalase (CAT) and superoxide dismutase (SOD) activities in leaves of both the varieties. Pseudomonas putida may be used either alone or in combination with Ag-nanoparticles to enhance the antioxidant and defense enzyme activities. Hence, the plant can tolerate the diseases and stresses in a much better way with higher protein and phenolics content.


2003 ◽  
Vol 185 (2) ◽  
pp. 399-404 ◽  
Author(s):  
Longkuan Xiang ◽  
Bradley S. Moore

ABSTRACT The novel benzoyl coenzyme A (benzoyl-CoA) biosynthesis pathway in “Streptomyces maritimus” was investigated through a series of target-directed mutations. Genes involved in benzoyl-CoA formation were disrupted through single-crossover homologous recombination, and the resulting mutants were analyzed for their ability to biosynthesize the benzoyl-CoA-primed polyketide antibiotic enterocin. Inactivation of the unique phenylalanine ammonia-lyase-encoding gene encP was previously shown to be absolutely required for benzoyl-CoA formation in “S. maritimus”. The fatty acid β-oxidation-related genes encH, -I, and -J, on the other hand, are necessary but not required. In each case, the yield of benzoyl-CoA-primed enterocin dropped below wild-type levels. We attribute the reduced benzoyl-CoA formation in these specific mutants to functional substitution and cross-talk between the products of genes encH, -I, and -J and the enzyme homologues of primary metabolism. Disruption of the benzoate-CoA ligase encN gene did not perturb enterocin production, however, demonstrating that encN is extraneous and that benzoic acid is not a pathway intermediate. EncN rather serves as a substitute pathway for utilizing exogenous benzoic acid. These experiments provide further support that benzoyl-CoA is formed in a novel bacterial pathway that resembles the eukaryotic assembly of benzoyl-CoA from phenylalanine via a β-oxidative path.


2002 ◽  
Vol 29 (1) ◽  
pp. 63 ◽  
Author(s):  
Odile Faivre-Rampant ◽  
Jean-Paul Charpentier ◽  
Claire Kevers ◽  
Jacques Dommes ◽  
Harry Van Onckelen ◽  
...  

The auxin and phenolic contents, as well as phenylalanine ammonia-lyase (PAL) activity, were determined in in vitro cultured shoots of the recalcitrant-to-root rac mutant of tobacco, and compared with wild-type shoots. The mutant and wild-type shoots showed similar auxin changes during the culture cycle, but with higher contents for the mutant. A transient peak of auxin (corresponding to the achievement of the rooting inductive phase) occurred at day 14 in both types of shoots, but earlier in the basal parts of the wild-type stems. The rac shoots contained more phenolics, corresponding with an increased PAL activity. The most abundant phenolic compound found in the two types of tobacco was chlorogenic acid, which was more abundant in the rac shoots. Rutin was also detected at a higher concentration in the mutant shoots. Basal parts of wild-type shoots treated with 10–3 M chlorogenic acid reacted by accumulating auxins and, unlike untreated controls, did not form adventitious roots. The relationships between these biochemical analyses in relation to the growth limitation of the rac mutant, and the inhibition of its root development, are discussed.


Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 389
Author(s):  
Silvia Medda ◽  
Leonarda Dessena ◽  
Maurizio Mulas

The leaves and berries of myrtle (Myrtus communis L.) are rich in phenolic compounds, such as phenolic acids, flavonoids, and flavanols. The richness of these antioxidant compounds allows the potential use of myrtle biomasses as raw materials for medicinal and functional food products. Most of the phenolic compounds originate from the phenylpropanoid pathway, where phenylalanine ammonia lyase (PAL) enzyme activates the first step. The objective of this research is to study the activity of PAL as related to accumulation in the myrtle fruits and leaves of some phenolic compounds in the period between blossom and full berry ripening. With this aim, we compared two model genotypes with different fruit coloration. In leaves and berries of two cultivars, ‘Giovanna’ with pigmented berries and ‘Grazia’ with white berries, the PAL activity and content of polyphenols, anthocyanins, flavonoids, and tannins were determined with spectrophotometric methods. PAL activity was quite constant in leaves and variable in berries: Greater in berries of ‘Giovanna’ than in those of ‘Grazia’ cultivar, and increasing from berry color-break to full ripening. In berries, a positive correlation between PAL and flavonoids (r = 0.44), and between PAL and anthocyanins (r = 0.69), as well as a negative correlation between PAL and total polyphenols (r = −0.471), were found.


Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 743-747 ◽  
Author(s):  
Robert E. Hoagland

Three-day-old soybean seedlings were treated with acifluorfen via liquid culture [50 μM in dark, 1 μM in light (200 μE·m–2·s–1)]. Root elongation in the dark was inhibited only slightly (6%) after 96 h. In the light, acifluorfen inhibited root elongation after 48 h; after 96 h, inhibition was 32%. Hypocotyl length was not affected in either the light or dark. Soluble hydroxyphenolic content per axis was unaffected in the dark but was reduced by about 13 to 25% at 24 to 96 h in the light. Extractable phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity per axis was unaltered by herbicide in the dark. A brief transient increase in PAL activity (4 to 24 h) in axes of light-grown seedlings in the presence of acifluorfen was followed by reduced enzyme levels compared to light-grown controls at 72 and 96 h. Although light is required for maximal herbicide action, there was no effect on anthocyanin or chlorophyll accumulation or on the chlorophyll a/b ratio in hypocotyls or light-grown seedlings.


2008 ◽  
Vol 54 (No. 7) ◽  
pp. 294-300 ◽  
Author(s):  
R. Yan ◽  
S. Gao ◽  
W. Yang ◽  
M. Cao ◽  
S. Wang ◽  
...  

<I>Jatropha curcas</I> L. embryos were germinated and grown in vitro under nickel concentrations of 100, 200, 400 and 800 &mu;mol to observe the effects of high nickel concentrations on seedling growth. Observed biological makers included biomass, and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and phenylalanine ammonia-lyase (PAL) in the cotyledons. The fresh weight of cotyledons in all the tested nickel concentrations was lower than that of the control, but dry weight of cotyledons increased with increasing nickel concentrations up to 200 &mu;mol. SOD activity increased significantly up to 400 &mu;mol and then decreased at 800 &mu;mol nickel. POD activities were induced remarkably at 100 and 200 &mu;mol, but the activity decreased with increasing nickel concentrations. Similarly, a negative link between CAT activity and nickel concentrations was observed in this experiment. PAL activity had a positive correlation to nickel concentrations, and the highest activity was found at 400 &mu;mol nickel. Electrophoresis analysis suggested that a significant correlation between nickel concentrations and isoenzyme patterns of SOD and POD was observed, and these results were consistent with the changes of the activity assayed in solutions.


2005 ◽  
Vol 32 (3) ◽  
pp. 267 ◽  
Author(s):  
N. P. Geetha ◽  
K. N. Amruthesh ◽  
R. G. Sharathchandra ◽  
H. S. Shetty

Phenylalanine ammonia lyase (PAL) activity was studied in pearl millet cultivars with different levels of resistance to the downy mildew disease caused by Sclerospora graminicola, an important oomycete pathogen. PAL activity was elevated in resistant host cultivar and decreased in susceptible cultivars following downy mildew pathogen infection. The enzyme activation varied between cultivars and was correlated with the degree of resistance to downy mildew disease. The induction of PAL as a response to pathogen inoculation was further corroborated by a time-course study in seedlings and cultured cells of pearl millet. The level of PAL activity was highest at 1.5 h in cultured cells and 4 h in seedlings of resistant host cultivar after inoculation with Sclerospora graminicola. Further studies on PAL activity in different tissues of seedlings showed highest enzyme activity in the young growing region of the root of the resistant host cultivars. The accumulation of wall-bound phenolics and lignin was higher in the resistant cultivar seedlings as evidenced by phloroglucinol–HCl staining and p-coumaric acid assay. The temporal changes in lignin concentration and the concentration of soluble phenolics were greater in root tissues of resistant cultivars than in those of susceptible cultivars. Treatment of resistant seedlings with a PAL inhibitor, α-aminooxy-β-phenylpropionic acid, resulted in the enhancement of the enzyme activity, whereas in the presence of 1 mm trans-cinnamic acid the pathogen-induced PAL was completely inhibited. Treatment of pearl millet seedlings with exogenously applied PAL inhibitors induced downy mildew disease susceptibility in the resistant pearl millet cultivar, consistent with direct involvement of PAL in downy mildew resistance. Results are discussed with respect to the presumed importance of host phenolic compounds and lignin accumulation and its relation to PAL activation as a response to the pathogen infection.


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