Induction Of Polyphenol Oxidase Research Articles

Induced Tomato Resistance Against Bemisia tabaci Triggered by Salicylic Acid, β-Aminobutyric Acid, and Trichoderma.

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) biotype B is a key pest of Solanum lycopersicum L. (Solanaceae) throughout the world. In this study, we examined the induction of resistance on tomato plants treated with SA, BABA, and Trichoderma either individually or in combination against B. tabaci biotype B through the assessment of some biological and behavioral aspects of this insect pest. Also, to understand the mode of action of these inducers, we correlated and analyzed the biochemical basis of plant resistance, by measuring levels of polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), and phenolic content in leaves of treated tomato plants. The longest development time of whitefly immature stages was recorded for plants treated with root β-aminobutyric acid application (RBABA) + root Trichoderma application (RT), root salicylic acid application (RSA) + RT, and RT. In a free-choice assay, B. tabaci adults showed a significantly lower preference for settling and oviposition in RBABA + RT, RSA + RT, and RT in comparison with control. In a no-choice assay, B. tabaci females laid significantly fewer eggs on treatments than those in control, with better results observed in RBABA + RT. Plants responded to different treatments and showed higher induction of PPO, POD, and PAL activities, besides the higher accumulation of phenols in RBABA + RT, RSA + RT, and RT treatments. These results suggest that RBABA + RT, RSA + RT, and RT could be utilized for the induction of effective plant defense against B. tabaci.

The insecticidal activity of Satureja hortensis essential oil and its active ingredient -carvacrol against Acrobasis advenella (Zinck.) (Lepidoptera, Pyralidae)

Nowadays, Acrobasis advenella is considered a pest of the highest economic significance in black chokeberry plantations, negatively affecting the quantity and quality of fruits. The aim of this study was to investigate the effect of Satureja hortensis essential oil and its main constituent, carvacrol, on the life cycle and physiology of A. advenella. The metabolic activity of both preparations was evaluated against insect α- and β- glucosidase, catalase, peroxidase and polyphenol oxidase. The results showed S. hortensis essential oil and carvacrol, are characterized by insecticidal activity against A. advenella larvae. It found an increase in catalase activity in A. advenella homogenates under the influence of carvacrol and an induction of polyphenol oxidase by S. hortensis EO with no changes in POX activity. Also, it was shown that the activity of α- and β-glucosidase significantly increased in larvae fed on inflorescences treated with the essential oil and carvacrol. These preparations particularly strongly affected β-glucosidase activity in the insect homogenates. S. hortensis essential oil reduced emergence the longevity of moths. The obtained results suggest that S. hortensis essential oil and carvacrol can be useful in protecting organic crops of black chokeberry but essential oils may be more effective biopesticides than their active ingredients separately.

Proteomic analysis of labial saliva of the generalist cabbage looper (Trichoplusia ni) and its role in interactions with host plants

Insect saliva is one of the first secretions to come in contact with plants during feeding. The composition and role of caterpillar saliva has not been as thoroughly studied as that of sucking insects. This study focuses on characterizing the proteome of the cabbage looper (Trichoplusia ni) saliva using iTRAQ labeling and LC-MS/MS. We also measured how the saliva proteome changed when larvae were reared on different diets – cabbage, tomato, and an artificial pinto bean diet. We identified 254 proteins in the saliva out of which 63 were differentially expressed. A large percentage (56%) of the proteins identified function in protein metabolism, followed by proteins involved in vesicle transport (6%) and oxidoreductase activity (5%), among other categories. Several proteins identified are antioxidants or reactive oxygen species (ROS) scavengers. Among these ROS scavengers, we identified a catalase and further analyzed its gene expression and enzymatic activity. We also applied commercial, purified catalase on tomato and measured the activity of defensive proteins – trypsin proteinase inhibitor, polyphenol oxidase and peroxidase. Catalase gene expression was significantly higher in the salivary glands of larvae fed on tomato. Also, catalase suppressed the induction of tomato trypsin proteinase inhibitor levels, but not the induction of polyphenol oxidase or peroxidase. These results add to our understanding of proteomic plasticity in saliva and its role in herbivore offense against plant defenses.

Induction of Polyphenol Oxidase in Walnut and Its Relationship to the Pathogenic Response to Bacterial Blight

Plants respond to pathogens with both active and passive defense mechanisms. These defense responses include the induction of defense or defense-related genes such as polyphenol oxidase (PPO) and pathogenesis-related (PR) proteins. The role of PPO in the interaction between bacterial blight [Xanthomonas arboricola pv. juglandis (Xaj)] and walnut (Juglans regia) was studied. JrPPO-1 and P14a genes were identified in two walnut cultivars, Chandler and Serr, using standard polymerase chain reaction (PCR) to understand their inducible ability in response to Xaj. ‘Serr’ and ‘Chandler’ were inoculated with Xaj strain 417. PPO activity in leaves was assayed at 0, 24, 72, 96, 120, and 144 hours after inoculation. Results showed a steady increase in activity commencing within 24 hours of inoculation. Increase in PPO activity was close to 2-fold greater in ‘Chandler’ than in ‘Serr’ at all time points examined. Real-time PCR analysis showed differences between cultivars in PPO gene expression. The JrPPO-1 gene was highly expressed in both cultivars 24 hours after inoculation but expression in ‘Serr’ was much greater than in ‘Chandler’. Significant expression of P14a gene was observed in both cultivars within 24 hours. Expression in ‘Serr’ was strong and maximized with a significant increase at 96 hours. Expression in ‘Chandler’ was far weaker than ‘Serr’ at 24 hours and did not increase further. Our results imply that the walnut–bacterial blight interaction induces the expression of JrPPO-1 and P14a as well as the activity of PPO.

Effect of phenolic acids from black currant, sour cherry and walnut on grain aphid (Sitobion avenae F.) development

The influence of naturally-occurring phenolic acid mixtures from selected plants was tested against the grain aphid (Sitobion avenae F.). Phenolic acids were extracted from the leaves of black currant (Ribes nigrum L.), sour cherry (Prunus cerasus L.) and walnut (Juglans regia L.), as well as from the green husks of walnut. The highest content of total phenolic acids and individual compounds such as p-hydroxybenzoic, p-coumaric, chlorogenic and vanillic acids were determined in J. regia. Ferulic and tannic acids were found only in J. regia. In laboratory bioassays, the phenolic acids extracted from plants prolonged the aphid prereproductive period by 1.5–3.0 days and reduced daily fecundity by 1–1.5 offspring. The strongest effects were observed after application of phenolic acids from the leaves and green husks of J. regia. The grain aphid used glutathione S-transferase (GST), peroxidase (POD) and polyphenol oxidase (PPO) in response to the application of plant phenolic acids. An increase in aphid GST activity was found in response to treatment with all extracts. Induction of PPO and POD was shown 24 h after the application of phenolic acids mixture from leaves of walnut; inhibition was observed after 48 and 168 h in response to treatment with both extracts of walnut. An inverse relationship between the POD and PPO activity of the aphids was found 24 h after application of the black currant and sour cherry phenolic acids. After 168 h, the activities of these enzymes were higher in treated aphids compared to unsprayed insects. Mixtures of phenolic acids naturally occurring in phenol-rich plants might be used as biopesticides to control the grain aphid as a part of an integrated pest management programme.

Methyl jasmonate induced responses in four plant species and its effect on Spodoptera litura Fab. performance

Defensive proteins, such as polyphenol oxidase (PPO) and trypsin inhibitor (TI), are induced by herbivore wounding and exogenous methyl jasmonate application in various plant species. This study was conducted to measure induction of PPO and TI in radish, sweet pepper, tomato, and water spinach plants following herbivore wounding (I), methyl jasmonate application (M), and a combination of the two treatments (M + I). The effect of induced responses was also examined against third instar Spodoptera litura Fab. PPO activity was induced in radish by treatment I only; in sweet pepper, by treatments I and M; in tomato, by treatments I, M, and M + I; and in water spinach, by treatments M and M + I. The activity of TI was enhanced 1.2–1.4-fold in radish, sweet pepper, and tomato by M and M + I treatments, whereas in water spinach, it was enhanced 1.2-fold by all 3 treatments. The relative growth rate (RGR) of S. litura was reduced by 53% on radish plants following M treatment only. It was reduced by 37% and 42% on sweet paper plants following M and M + I treatment, respectively. RGR was significantly reduced on test tomato plants following I, M, and M + I treatments. The RGR of S. litura was unaffected on water spinach plants following any treatment. Collectively, the results of this study indicated that induction of plant defensive proteins in response to S. litura feeding or exogenous methyl jasmonate application varied among plant species, which further affected the induced plant resistance to the caterpillars.

Effect of jasmonic acid on the induction of polyphenoloxidase and peroxidase activities in relation to date palm resistance against Fusarium oxysporum f. sp. albedinis

Bayoud, caused by Fusarium oxysporum f. sp. albedinis (Foa), is the most damaging disease of date palm in Morocco. In the present study we have investigated the effect of jasmonic acid (JA) on two defence-related enzymes, namely peroxidases (POX) and polyphenoloxidases (PPO) in date palm seedlings root. Our data show that exogenous application of JA at a concentration of 50 μM increased the activity of both enzymes. The increase of POX activity in the presence of JA was much more important than that observed following infection with the pathogen. As compared to untreated plants, PPO activity was 2.2 and 1.3 times higher in BSTN and JHL cultivars respectively. In addition, PAGE analysis revealed increased band intensity of the major constitutive isoforms of POX and PPO in both JA-treated and Foa-treated seedlings. Close examination of symptomatic and asymptomatic plants showed that root tissues of symptomatic plants were massively colonized by Foa. Also, disease development in these plants appeared to involve a marked degradation of the host cell walls early during the process of pathogen invasion. In contrast, the presence of Foa in asymptomatic plants induced limited necrotic lesions (hypersensitive-reaction like lesions) that were probably involved in reducing the progression of the pathogen. Together, our findings indicate that JA is capable of enhancing date palm root resistance to infection by Foa via the activation of defence-related enzymes such as PPO and POX.

Pseudomonas fluorescens enhances resistance and natural enemy population in rice plants against leaffolder pest

AbstractPlant growth promoting fluorescent pseudomonad strains Pf1, TDK1 and PY15 were evaluated for their efficacy against leaffolder (Cnaphalocrocis medinalis) pest in rice plants under field conditions individually and in combinations. Application of mixtures of Pseudomonas fluorescens strains Pf1, TDK1 and PY15 significantly reduced the leaffolder damage in rice plants compared with untreated control. Interestingly, natural enemy population in plots treated with P. fluorescens was greater than the chemical and untreated controls. Further, support for these results was gathered by assaying activities of polyphenol oxidase (PPO) and lipoxygenase (LOX) under glasshouse conditions. The results showed the higher activity of PPO and LOX in plants treated with P. fluorescens mixtures (Pf1 + TDK1 + PY15) than the plants treated with individual strains, chemical and untreated controls. Further, fluorescent pseudomonad mixtures increased the rice yield compared with individual strain and non‐bacterized treatments. The present study reveals that in addition to plant growth promotion, plant growth‐promoting rhizobacterial (PGPR) strains‐mediated induction of PPO and LOX in rice plants could be involved in enhanced natural enemy populations and resistance mechanisms against leaffolder attack.

PGPR mediates induction of pathogenesis-related (PR) proteins against the infection of blast pathogen in resistant and susceptible ragi [Eleusine coracana (L.) Gaertner] cultivars

The Pseudomonas fluorescens isolate 1 (Pf1) was found to protect the ragi [Eleusine coracana (L.) Gaertner] blast fungus, Pyricularia grisea. Induction of defense proteins viz. chitinase, β-1,3 glucanase, peroxidase (PO) and polyphenol oxidase (PPO) by the Pf1 isolate was studied against P. grisea. Chitinase in a resistant, susceptible and commonly used cultivar with and without challenge inoculation of P. grisea, revealed changes in the isoform pattern by UV illumination after staining the gel with fluorescent brightner 28. Native PAGE (polyacrylamide gel electrophoresis) of PO showed the single isoform in all the treatments including the control and a significant increase in the intensity of the band in the inoculated control and Pf1 treatment in all the varieties. Isoform analysis of PPO showed the induction of PPO in P. fluorescens treated plants challenged with P. grisea.

Polyphenol oxidase from hybrid poplar. Cloning and expression in response to wounding and herbivory.

The inducible expression of polyphenol oxidase (PPO), a presumed antiherbivore enzyme, was examined in hybrid poplar (Populus trichocarpa x Populus deltoides). Following mechanical wounding simulating insect damage, PPO activity increased dramatically in wounded and unwounded leaves on wounded plants beginning at 24 and 48 h, respectively. A hybrid poplar PPO cDNA was isolated and its nucleotide sequence determined. On northern blots, PPO transcripts were detected within 8 h of wounding, and reached peak levels at 16 and 24 h in wounded and unwounded leaves, respectively. Methyl jasmonate spray and feeding by forest tent caterpillar also induced PPO expression. The induction of PPO was strongest in the youngest four leaves, which were generally avoided by caterpillars in free feeding experiments. This wound- and herbivore-induced expression of PPO in hybrid poplar supports the defensive role of this protein against insect pests.

Expression and Induction of Polyphenol Oxidase in Apple (Malus pumila) Cell Culture

The expression and induction of polyphenol oxidase (PPO) in apple cell culture were examined. PPO activities were measured using chlorogenic acid or L-Dopa as the substrate. The isozymes of PPO were analyzed by electrophoresis and Western blotting. The isozymes expressed in cell culture were different from those in fruit and leaf. Chlorogenic acid oxidase activity in cell culture was raised 10 times by adding macerozyme, and a new isozyme of L-Dopa oxidase was induced by adding it to the culture.

Biochemical Basis of Resistance of Tobacco Callus Tissue Cultures to Hydroxyphenylethylamines.

It has been reported that hydroxyphenylethylamines, such as tyramine and octopamine, are toxic to tobacco (Nicotiana tabacum L.) callus cultures grown in the presence of auxins, whereas calli grown in the presence of cytokinins and crown gall cultures are resistant to these amines (P. Christou and K.A. Barton [1989] Plant Physiol 89: 564-568). In an attempt to understand the underlying mechanism of this resistance, we compared the fates of tyramine in tyramine-sensitive and tyramine-resistant tobacco tissue cultures (cv Xanthi nc). The very rapid formation of black-colored oxidation products from tyramine in sensitive tissues suggested that the toxicity might be caused by the oxidation of tyramine by phenol oxidases present in the tissues or released into the medium after subculture. This was confirmed through many indirect procedures (effect of exogenously added tyrosinase, induction of polyphenol oxidase [PPO] activity by auxin, etc.). The study of tyramine structure-activity relationships further suggested that the toxicity of tyramine might be due to the formation of indolequinones after oxidation by PPO. Subculture of calli grown on 2,4-dichlorophenoxyacetic acid in a medium containing benzyladenine triggered a slow decrease in PPO activity and dramatic increases in peroxidase and tyramine hydroxycinnamoyl transferase (THT) activities. THT was undetectable in calli grown on 2,4-dichlorophenoxyacetic acid but very active in tyramine-resistant crown gall cultures. Moreover, when [3H]tyramine was fed in vivo to tyramine-resistant tissues, it was rapidly integrated into cell walls in the wound periderm formed at the periphery of the calli. Both the conjugation of tyramine and its integration into cell walls could compete with the formation of toxic quinones and therefore play a part in the resistance. Thus, it seems likely that the control of the toxicity of hydroxyphenylethylamines by cytokinins results primarily from changes in the metabolism and the compartmentation of these amines.

A possible function of cyclic AMP in the induction of polyphenol oxidase preceding root formation in cultured carrot-root callus

A possible function of cyclic AMP in the induction of polyphenol oxidase preceding root formation in cultured carrot-root callus

Induction of polyphenol oxidase in germinating wheat seeds

A 50- and 100-fold increase in the o-diphenolase activity was observed respectively in excised coleoptiles and roots of wheat seedlings after germination for 4–5 days. This increased activity was associated with the appearance of several new multiple forms of o-diphenolase on acrylamide gels. The embryo-less half-seeds dissected from seedlings, however, revealed only a three-fold increase in o-diphenolase activity, without any alteration in the pattern of multiple forms. Cycloheximide substantially inhibited the activity and appearance of multiple forms of o-diphenolase, whereas actinomycin D failed to bring about a similar response. Protein synthesis was probably necessary for the formation of new multiple forms. Unlike o-diphenolase activity which was present in all parts of the seedling, the monophenolase activity was confined to the embryo-less endosperm. A 5–7-fold increase in monophenolase activity was observed in the embryo-less half-seed dissected from the seedling. A single broad band of monophenolase developed on acrylamide gels. This persisted during the early period of seed germination without addition of new multiple forms. No inhibition of monophenolase activity was observed in seeds treated with cycloheximide or actinomycin D.