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plant polyphenol oxidases

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https://www.readbyqxmd.com/read/29218491/a-specific-amino-acid-residue-in-the-catalytic-site-of-dandelion-polyphenol-oxidases-acts-as-selector-for-substrate-specificity
#1
Sarah M Prexler, Ratna Singh, Bruno M Moerschbacher, Mareike E Dirks-Hofmeister
Successful site-directed mutagenesis combined with in silico modeling and docking studies for the first time offers experimental proof of the role of the 'substrate selector' residue in plant polyphenol oxidases. The plant and fungi enzymes responsible for tissue browning are called polyphenol oxidases (PPOs). In plants, PPOs often occur as families of isoenzymes which are differentially expressed, but little is known about their physiological roles or natural substrates. In a recent study that explored these structure-function relationships, the eleven known dandelion (Taraxacum officinale) PPOs were shown to separate into two different phylogenetic groups differing in catalytic cavity architecture, kinetic parameters, and substrate range...
December 7, 2017: Plant Molecular Biology
https://www.readbyqxmd.com/read/29188401/drought-stress-promotes-the-colonization-success-of-a-herbivorous-mite-that-manipulates-plant-defenses
#2
Miguel G Ximénez-Embún, Joris J Glas, Felix Ortego, Juan M Alba, Pedro Castañera, Merijn R Kant
Climate change is expected to bring longer periods of drought and this may affect the plant's ability to resist pests. We assessed if water deficit affects the tomato russet mite (TRM; Aculops lycopersici), a key tomato-pest. TRM thrives on tomato by suppressing the plant's jamonate defenses while these defenses typically are modulated by drought stress. We observed that the TRM population grows faster and causes more damage on drought-stressed plants. To explain this observation we measured several nutrients, phytohormones, defense-gene expression and the activity of defensive proteins in plants with or without drought stress or TRM...
November 29, 2017: Experimental & Applied Acarology
https://www.readbyqxmd.com/read/29186815/characterization-of-the-transcriptome-and-gene-expression-of-tetraploid-black-locust-cuttings-in-response-to-etiolation
#3
(no author information available yet)
Etiolation (a process of growing plants in partial or complete absence of light) promotes adventitious root formation in tetraploid black locust (Robinia pseudoacacia L.) cuttings. We investigated the mechanism underlying how etiolation treatment promotes adventitious root formation in tetraploid black locust and assessed global transcriptional changes after etiolation treatment. Solexa paired-end sequencing of complementary DNAs (cDNAs) from control (non-etiolated, NE) and etiolated (E) samples resulted in 107,564 unigenes...
November 24, 2017: Genes
https://www.readbyqxmd.com/read/29177786/nematicidal-potential-and-specific-enzyme-activity-enhancement-potential-of-neem-azadirachta-indica-a-juss-aerial-parts
#4
Arti Shivraj Nile, Shivraj Hariram Nile, Young Soo Keum, Doo Hwan Kim, Baskar Venkidasamy, Sathishkumar Ramalingam
Nematodes are considered as major plant parasites damaging most of the crops, and neem plant exhibits potential nematicidal and insecticidal properties. This study aimed to check nemato-toxic potential of neem (Azadirachta indica) plant using in vitro and in-planta trials against Meloidogyne incognita. The findings suggested that the neem extracts were lethal to second-stage juvenile (J2) and egg hatching with simultaneous enhancement in treated tomato plant growth. The egg numbers of M. incognita found less sensitive to the aqueous and alcoholic extracts than those of J2 as per LC50 values...
November 25, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29161274/bacillus-spp-a-bio-control-agent-enhances-the-activity-of-antioxidant-defense-enzymes-in-rice-against-pyricularia-oryzae
#5
Afroz Rais, Zahra Jabeen, Faluk Shair, Fauzia Yusuf Hafeez, Muhammad Nadeem Hassan
Plant growth promoting rhizobacteria (PGPR) are found to control the plant diseases by adopting various mechanisms. Induced systemic resistance (ISR) is an important defensive strategy manifested by plants against numerous pathogens especially infecting at aerial parts. Rhizobacteria elicit ISR by inducing different pathways in plants through production of various metabolites. In the present study, potential of Bacillus spp. KFP-5, KFP-7, KFP-17 was assessed to induce antioxidant enzymes against Pyricularia oryzae infection in rice...
2017: PloS One
https://www.readbyqxmd.com/read/29149645/xylella-fastidiosa-induces-differential-expression-of-lignification-related-genes-and-lignin-accumulation-in-tolerant-olive-trees-cv-leccino
#6
Erika Sabella, Andrea Luvisi, Alessio Aprile, Carmine Negro, Marzia Vergine, Francesca Nicolì, Antonio Miceli, Luigi De Bellis
Recently, Xylella fastidiosa was reported in Italy, associated with the "Olive Quick Decline Syndrome". The cv. Leccino exhibits an evident tolerance with a slow disease progression compared with the other cultivars. Between the mechanisms proposed to explain the putative tolerance of some hosts to X. fastidiosa diseases, lignin deposition plays an important role. Analysis of phenolic compounds in healthy and infected Leccino and Cellina di Nardò leaves showed, in the two cultivars, a reduction of hydroxytyrosol glucoside (usually associated with drought and cold stress) and, only in Leccino, an increase of quinic acid, precursor of lignin...
November 10, 2017: Journal of Plant Physiology
https://www.readbyqxmd.com/read/29142408/correlation-between-polyphenol-oxidase-ppo-activity-and-total-phenolic-contents-in-crocus-sativus-l-corms-during-dormancy-and-sprouting-stages
#7
Nardana Esmaeili, Hassan Ebrahimzadeh, Khosrou Abdi
Purification and characterization of polyphenol oxidase (PPO) enzyme and determination of total phenolic contents during dormancy and sprouting stages in Crocus sativus corms were performed. PPO enzyme was purified by ammonium sulfate precipitation and ion-exchange chromatography using DEAE-Sephadex A25 and two isoenzymes were obtained on the SDS-PAGE, which corresponded to molecular weights of 70 and 54 kDa. The Km values of the enzyme were 4.87 and 2.12 mM for l-DOPA in dormancy and waking stages, respectively...
October 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/29084178/comparative-morphology-transcription-and-proteomics-study-revealing-the-key-molecular-mechanism-of-camphor-on-the-potato-tuber-sprouting-effect
#8
Li-Qin Li, Xue Zou, Meng-Sheng Deng, Jie Peng, Xue-Li Huang, Xue Lu, Chen-Cheng Fang, Xi-Yao Wang
Sprouting regulation in potato tubers is important for improving commercial value and producing new plants. Camphor shows flexible inhibition of tuber sprouting and prolongs the storage period of potato, but its underlying mechanism remains unknown. The results of the present study suggest that camphor inhibition caused bud growth deformities and necrosis, but after moving to more ventilated conditions, new sprouts grew from the bud eye of the tuber. Subsequently, the sucrose and fructose contents as well as polyphenol oxidase (PPO) activity were assessed after camphor inhibition...
October 30, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29067700/polyphenol-oxidase-from-pectobacterium-atrosepticum-identification-and-cloning-of-gene-and-characteristics-of-the-enzyme
#9
Vladimir Gorshkov, Nadezhda Tarasova, Natalia Gogoleva, Elena Osipova, Olga Petrova, Evgeny Kovtunov, Yuri Gogolev
In the present study, we attempted to elucidate if the harmful phytopathogenic bacteria of Pectobacterium genus (P. atrosepticum) possess the enzymes for oxidation of phenolic compounds. Polyphenol oxidase (laccase) activity was revealed in P. atrosepticum cell lysates. Using bioinformatic analysis, an ORF encoding a putative copper-containing polyphenol oxidase of 241 amino acids with a predicted molecular mass of 25.9 kDa was found. This protein (named Pal1) shares significant level of identity with laccases of a new type described for several bacterial species...
October 25, 2017: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/29062306/the-pgpr-stenotrophomonas-maltophilia-sbp-9-augments-resistance-against-biotic-and-abiotic-stress-in-wheat-plants
#10
Rajnish P Singh, Prabhat N Jha
Certain plant growth promoting bacteria have ability to ameliorate abiotic and/or biotic stressors, which can be exploited to enhance plant growth and productivity of the plants under stress conditions. Therefore, the present study aimed to examine the role of a rhizospheric bacterial isolate SBP-9 isolated from Sorghum bicolor (i) in promoting the wheat plant growth under salinity stress, and (ii) in enhancing the defense response in wheat against fungal pathogen "Fusarium graminearum." The test isolate possessed plant growth promoting (PGP) traits including ACC deaminase (ACCD), gibberellic acid, indole acetic acid (IAA), siderophore, and inorganic phosphate solubilization...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29061198/biochemical-responses-induced-in-galls-of-three-cynipidae-species-in-oak-trees
#11
I Kot, A Jakubczyk, M Karaś, U Złotek
Gall-making Cynipidae manipulate the leaves of host plant to form galls where offspring find shelter and food. The relationship between oak gallwasp and biochemical mechanisms of galls still requires a better understanding. So, in this research, protein and phenolic compound contents, as well as the activity of antioxidative enzymes and pathogenesis-related (PR) proteins were determined. Galls caused by asexual generation of Cynips quercusfolii L., Neuroterus numismalis (Fourc.) and N. quercusbaccarum L., as a model were used...
October 24, 2017: Bulletin of Entomological Research
https://www.readbyqxmd.com/read/29017399/recombinant-expression-purification-and-characterization-of-polyphenol-oxidase-2-vvppo2-from-shine-muscat-vitis-labruscana-bailey-%C3%A3-vitis-vinifera-l
#12
Ayako Katayama-Ikegami, Yuka Suehiro, Takane Katayama, Kazushi Jindo, Hiroyuki Itamura, Tomoya Esumi
Polyphenol oxidases (PPOs) catalyze browning reactions in various plant organs, therefore controlling the reactions is important for the food industry. PPOs have been assumed to be involved in skin browning of white grape cultivars; however, the molecular mechanism underlying PPO-mediated browning process remains elusive. We have recently identified a new PPO gene named VvPPO2 from "Shine Muscat" (Vitis labruscana Bailey × V. vinifera L.), and have shown that the gene is transcribed at a higher level than the previously identified VvPPO1 in browning, physiologically disordered berry skins at the maturation stage...
October 11, 2017: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/28918276/phytoremediation-of-soil-co-contaminated-with-cd-and-bde-209-using-hyperaccumulator-enhanced-by-am-fungi-and-surfactant
#13
Hui Li, Xing Li, Lei Xiang, Hai Ming Zhao, Yan Wen Li, Quan Ying Cai, Li Zhu, Ce Hui Mo, Ming Hung Wong
Pot experiments were conducted to investigate the uptake and translocation of both Cd and decabromodiphenyl ether (BDE-209) in Solanum nigrum, under the treatments of two arbuscular mycorrhizal fungi [AMF, Funneliformis mosseae (FM) and Rhizophagus intraradices (RI)] and surfactant β-cyclodextrin (β-CD). Results showed that S. nigrum treated with either FM or β-CD significantly elevated shoot biomass and Cd concentrations and contents in shoots. The concentrations of BDE-209 in shoots and the dissipation and debromination efficiencies of BDE-209 in soil were significantly enhanced in S...
February 1, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/28917191/enhanced-arabidopsis-disease-resistance-against-botrytis-cinerea-induced-by-sulfur-dioxide
#14
Meizhao Xue, Huilan Yi
Sulfur dioxide (SO2) is a common air pollutant that has complex impacts on plants. The effect of prior exposure to 30mgm(-3) SO2 on defence against Botrytis cinerea (B. cinerea) in Arabidopsis thaliana and the possible mechanisms of action were investigated. The results indicated that pre-exposure to 30mgm(-3) SO2 resulted in significantly enhanced resistance to B. cinerea infection. SO2 pre-treatment significantly enhanced the activities of defence-related enzymes including phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), β-1,3-glucanase (BGL) and chitinase (CHI)...
January 2018: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28879466/involvement-of-metabolic-components-volatile-compounds-pr-proteins-and-mechanical-strengthening-in-multilayer-protection-of-cucumber-plants-against-rhizoctonia-solani-activated-by-trichoderma-atroviride-trs25
#15
Justyna Nawrocka, U Małolepsza, K Szymczak, M Szczech
In the present study, the spread of Rhizoctonia solani-induced disease was limited when cucumber plants were pretreated with Trichoderma atroviride TRS25. The systemic disease suppression was related to TRS25-induced resistance (TISR) induction with simultaneous plant growth promotion. Protection of cucumber was related to enhanced activity of defense enzymes, e.g., guaiacol peroxidase (GPX), syringaldazine peroxidase (SPX), phenylalanine ammonia lyase (PAL), and polyphenol oxidase (PPO) as well as phenolic (PC) concentration increases in the conditions of hydrogen peroxide (H2O2) accumulation, resulting in thiobarbituric acid reactive substance (TBARS) decrease...
September 6, 2017: Protoplasma
https://www.readbyqxmd.com/read/28851884/cu-chitosan-nanoparticle-boost-defense-responses-and-plant-growth-in-maize-zea-mays-l
#16
Ram Chandra Choudhary, R V Kumaraswamy, Sarita Kumari, S S Sharma, Ajay Pal, Ramesh Raliya, Pratim Biswas, Vinod Saharan
In agriculture, search for biopolymer derived materials are in high demand to replace the synthetic agrochemicals. In the present investigation, the efficacy of Cu-chitosan nanoparticles (NPs) to boost defense responses against Curvularia leaf spot (CLS) disease of maize and plant growth promotry activity were evaluated. Cu-chitosan NPs treated plants showed significant defense response through higher activities of antioxidant (superoxide dismutase and peroxidase) and defense enzymes (polyphenol oxidase and phenylalanine ammonia-lyase)...
August 29, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821733/three-recombinantly-expressed-apple-tyrosinases-suggest-the-amino-acids-responsible-for-mono-versus-diphenolase-activity-in-plant-polyphenol-oxidases
#17
Ioannis Kampatsikas, Aleksandar Bijelic, Matthias Pretzler, Annette Rompel
Tyrosinases and catechol oxidases belong to the polyphenol oxidase (PPO) enzyme family, which is mainly responsible for the browning of fruits. Three cDNAs encoding PPO pro-enzymes have been cloned from leaves of Malus domestica (apple, MdPPO). The three pro-enzymes MdPPO1-3 were heterologously expressed in E. coli yielding substantial amounts of protein and have been characterized with regard to their optimum of activity resulting from SDS, acidic and proteolytic activation. Significant differences were found in the kinetic characterization of MdPPO1-3 when applying different mono- and diphenolic substrates...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28818380/molecular-cloning-and-expression-analysis-of-duplicated-polyphenol-oxidase-genes-reveal-their-functional-differentiations-in-sorghum
#18
Song Yan, Sujuan Li, Guowei Zhai, Ping Lu, Hui Deng, Shan Zhu, Renliang Huang, Jianfeng Shao, Yuezhi Tao, Guihua Zou
Polyphenol oxidase (PPO) is believed to play a role in plant growth, reproduction, and resistance to pathogens and pests. PPO causes browning of grains in cereals. In this study, genetic mapping of sorghum grain for phenol color reaction (PHR) was performed using a recombinant inbred line population. Only one locus was detected between SSR markers SM06072 and Xtxp176 on chromosome 6. Two linked orthologous genes (Sb06PPO1 and Sb06PPO2) within the mapped region were discovered and cloned. Transformation experiments using Nipponbare (a PHR negative rice cultivar) showed that Sb06PPO1 from LTR108 and two Sb06PPO2 alleles from both varieties could complement Nipponbare, whereas Sb06PPO1 from 654 could not...
October 2017: Plant Science: An International Journal of Experimental Plant Biology
https://www.readbyqxmd.com/read/28808325/phytoremediation-potential-of-acorus-calamus-in-soils-co-contaminated-with-cadmium-and-polycyclic-aromatic-hydrocarbons
#19
Nasreen Jeelani, Wen Yang, Lingqian Xu, Yajun Qiao, Shuqing An, Xin Leng
Phytoremediation is a promising technology for the remediation of sites co-contaminated with inorganic (heavy metal) and organic pollutants. A greenhouse experiment was conducted to investigate the independent and interactive effects of cadmium (Cd) and polycyclic aromatic hydrocarbons (PAHs) on the growth of the wetland plant Acorus calamus and its ability to uptake, accumulate, and remove pollutants from soils. Our results showed that growth and biomass of A. calamus were significantly influenced by the interaction of Cd and PAHs after 60 days of growth...
August 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28777094/in-crystallo-activity-tests-with-latent-apple-tyrosinase-and-two-mutants-reveal-the-importance-of-the-mutated-sites-for-polyphenol-oxidase-activity
#20
Ioannis Kampatsikas, Aleksandar Bijelic, Matthias Pretzler, Annette Rompel
Tyrosinases are type 3 copper enzymes that belong to the polyphenol oxidase (PPO) family and are able to catalyze both the ortho-hydroxylation of monophenols and their subsequent oxidation to o-quinones, which are precursors for the biosynthesis of colouring substances such as melanin. The first plant pro-tyrosinase from Malus domestica (MdPPO1) was recombinantly expressed in its latent form (56.4 kDa) and mutated at four positions around the catalytic pocket which are believed to influence the activity of the enzyme...
August 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
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