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Sample records for ammonia-lyases

  1. Priming ammonia lyases and aminomutases for industrial and therapeutic applications

    NARCIS (Netherlands)

    Heberling, Matthew M.; Wu, Bian; Bartsch, Sebastian; Janssen, Dick B.; Truppo, Matthew D.; Turner, Nicholas J.

    2013-01-01

    Ammonia lyases (AL) and aminomutases (AM) are emerging in green synthetic routes to chiral amines and an AL is being explored as an enzyme therapeutic for treating phenylketonuria and cancer. Although the restricted substrate range of the wild-type enzymes limits their widespread application, the no

  2. HISTIDINE BIOTRANSFORMATION MEDIATED BY L-HISTIDINE-AMMONIA-LYASE

    OpenAIRE

    Borisova, G.; Bessonova, O.

    2013-01-01

    Kinetics of the metabolism of the heterocyclic amino acid histidine exposed to the L-histidine ammonia-lyase enzyme has been investigated and the technology of extraction of histidine biotransformation products (urocanic acid and ammonia) from casein hydrolyzates enabling the subsequent use of these hydrolyzates as a milk protein concentrate for the production of specialized dietary products for the nutrition of histidinemia patients has been developed.

  3. In vivo synthesis of histidine by a cloned histidine ammonia-lyase in Escherichia coli.

    OpenAIRE

    Fuchs, R L; Kane, J F

    1985-01-01

    Histidine ammonia-lyase catalyzes the first step in histidine catabolism, the deamination of histidine to urocanate and ammonia. In vitro experiments have shown that histidine ammonia-lyase also can catalyze the reverse (amination) reaction, histidine synthesis, relatively efficiently under extreme reaction conditions (4 M NH4OH, pH 10). An Escherichia coli hisB deletion strain was transformed with a pBR322 derivative plasmid (pCB101) containing the entire Klebsiella aerogenes histidine utili...

  4. Genomic Characterization of Phenylalanine Ammonia Lyase Gene in Buckwheat.

    Directory of Open Access Journals (Sweden)

    Karthikeyan Thiyagarajan

    Full Text Available Phenylalanine Ammonia Lyase (PAL gene which plays a key role in bio-synthesis of medicinally important compounds, Rutin/quercetin was sequence characterized for its efficient genomics application. These compounds possessing anti-diabetic and anti-cancer properties and are predominantly produced by Fagopyrum spp. In the present study, PAL gene was sequenced from three Fagopyrum spp. (F. tataricum, F. esculentum and F. dibotrys and showed the presence of three SNPs and four insertion/deletions at intra and inter specific level. Among them, the potential SNP (position 949th bp G>C with Parsimony Informative Site was selected and successfully utilised to individuate the zygosity/allelic variation of 16 F. tataricum varieties. Insertion mutations were identified in coding region, which resulted the change of a stretch of 39 amino acids on the putative protein. Our Study revealed that autogamous species (F. tataricum has lower frequency of observed SNPs as compared to allogamous species (F. dibotrys and F. esculentum. The identified SNPs in F. tataricum didn't result to amino acid change, while in other two species it caused both conservative and non-conservative variations. Consistent pattern of SNPs across the species revealed their phylogenetic importance. We found two groups of F. tataricum and one of them was closely related with F. dibotrys. Sequence characterization information of PAL gene reported in present investigation can be utilized in genetic improvement of buckwheat in reference to its medicinal value.

  5. Genomic Characterization of Phenylalanine Ammonia Lyase Gene in Buckwheat.

    Science.gov (United States)

    Thiyagarajan, Karthikeyan; Vitali, Fabio; Tolaini, Valentina; Galeffi, Patrizia; Cantale, Cristina; Vikram, Prashant; Singh, Sukhwinder; De Rossi, Patrizia; Nobili, Chiara; Procacci, Silvia; Del Fiore, Antonella; Antonini, Alessandro; Presenti, Ombretta; Brunori, Andrea

    2016-01-01

    Phenylalanine Ammonia Lyase (PAL) gene which plays a key role in bio-synthesis of medicinally important compounds, Rutin/quercetin was sequence characterized for its efficient genomics application. These compounds possessing anti-diabetic and anti-cancer properties and are predominantly produced by Fagopyrum spp. In the present study, PAL gene was sequenced from three Fagopyrum spp. (F. tataricum, F. esculentum and F. dibotrys) and showed the presence of three SNPs and four insertion/deletions at intra and inter specific level. Among them, the potential SNP (position 949th bp G>C) with Parsimony Informative Site was selected and successfully utilised to individuate the zygosity/allelic variation of 16 F. tataricum varieties. Insertion mutations were identified in coding region, which resulted the change of a stretch of 39 amino acids on the putative protein. Our Study revealed that autogamous species (F. tataricum) has lower frequency of observed SNPs as compared to allogamous species (F. dibotrys and F. esculentum). The identified SNPs in F. tataricum didn't result to amino acid change, while in other two species it caused both conservative and non-conservative variations. Consistent pattern of SNPs across the species revealed their phylogenetic importance. We found two groups of F. tataricum and one of them was closely related with F. dibotrys. Sequence characterization information of PAL gene reported in present investigation can be utilized in genetic improvement of buckwheat in reference to its medicinal value. PMID:26990297

  6. Genomic Characterization of Phenylalanine Ammonia Lyase Gene in Buckwheat

    Science.gov (United States)

    Thiyagarajan, Karthikeyan; Vitali, Fabio; Tolaini, Valentina; Galeffi, Patrizia; Cantale, Cristina; Vikram, Prashant; Singh, Sukhwinder; De Rossi, Patrizia; Nobili, Chiara; Procacci, Silvia; Del Fiore, Antonella; Antonini, Alessandro; Presenti, Ombretta; Brunori, Andrea

    2016-01-01

    Phenylalanine Ammonia Lyase (PAL) gene which plays a key role in bio-synthesis of medicinally important compounds, Rutin/quercetin was sequence characterized for its efficient genomics application. These compounds possessing anti-diabetic and anti-cancer properties and are predominantly produced by Fagopyrum spp. In the present study, PAL gene was sequenced from three Fagopyrum spp. (F. tataricum, F. esculentum and F. dibotrys) and showed the presence of three SNPs and four insertion/deletions at intra and inter specific level. Among them, the potential SNP (position 949th bp G>C) with Parsimony Informative Site was selected and successfully utilised to individuate the zygosity/allelic variation of 16 F. tataricum varieties. Insertion mutations were identified in coding region, which resulted the change of a stretch of 39 amino acids on the putative protein. Our Study revealed that autogamous species (F. tataricum) has lower frequency of observed SNPs as compared to allogamous species (F. dibotrys and F. esculentum). The identified SNPs in F. tataricum didn’t result to amino acid change, while in other two species it caused both conservative and non-conservative variations. Consistent pattern of SNPs across the species revealed their phylogenetic importance. We found two groups of F. tataricum and one of them was closely related with F. dibotrys. Sequence characterization information of PAL gene reported in present investigation can be utilized in genetic improvement of buckwheat in reference to its medicinal value. PMID:26990297

  7. Phenylalanine ammonia-lyase through evolution: A bioinformatic approach

    Directory of Open Access Journals (Sweden)

    Shiva Hemmati

    2015-03-01

    Full Text Available Phenylalanine ammonia-lyase (PAL is the first entry enzyme of the phenylpropanoid pathway that converts phenylalanine to cinnamic acid which is the precursor of various secondary metabolites. PAL is recently formulated for phenylketonuric patients in pegylated forms; therefore, screening a PAL with the highest affinity to the substrate is of a great importance. PAL exists in all higher plants and some fungi and few bacteria. Ancestors of land plants have been adopted by evolving metabolic pathways. A multi-gene family encodes PAL by gene duplication events in most plants. In this study, the taxonomic distribution and phylogeny of pal gene found in land plants, fungi and bacteria have been analyzed. It seems that the ancestor of plants acquired a pal gene via horizontal gene transfer in symbioses with bacteria and fungi. Gymnosperms have kept a diverse set of pal genes that arose from gene duplication events. In angiosperms, after the divergence of dicotyledons from monocots, pal genes were duplicated many times. The close paralogues of pal genes in some species indicate expansion of gene families after the divergence in plant pal gene evolution. Interestingly, some of the plant pals clustered by species in a way that pals within one species are more closely related to each other than to homologs in the other species which indicates this duplication event occurred more recently.

  8. Reduced phenylalanine ammonia-lyase and tyrosine ammonia-lyase activities and lignin synthesis in wheat grown under low pressure sodium lamps

    Science.gov (United States)

    Guerra, D.; Anderson, A. J.; Salisbury, F. B.

    1985-01-01

    Wheat (Triticum aestivum L. cv Fremont) grown in hydroponic culture under 24-hour continuous irradiation at 560 to 580 micromoles per square meter per second from either metalhalide (MH), high pressure sodium (HPS), or low pressure sodium (LPS) lamps reached maturity in 70 days. Grain yields were similar under all three lamps, although LPS-grown plants lodged at maturity. Phenylalanine ammonia-lyase (PAL) and a tyrosine ammonia lyase (TAL) with lesser activity were detected in all extracts of leaf, inflorescence, and stem. Ammonia-lyase activities increased with age of the plant, and plants grown under the LPS lamp displayed PAL and TAL activities lower than wheat cultured under MH and HPS radiation. Greenhouse solar-grown wheat had the highest PAL and TAL activities. Lignin content of LPS-grown wheat was also significantly reduced from that of plants grown under MH or HPS lamps or in the greenhouse, showing a correlation with the reduced PAL and TAL activities. Ratios of far red-absorbing phytochrome to total phytochrome were similar for all three lamps, but the data do not yet warrant a conclusion about specific wavelengths missing from the LPS lamps that might have induced PAL and TAL activities in plants under the other lamps.

  9. Alteration of the Diastereoselectivity of 3-Methylaspartate Ammonia Lyase by Using Structure-Based Mutagenesis

    NARCIS (Netherlands)

    Raj, Hans; Weiner, Barbara; Puthan Veetil, Vinod; Reis, Carlos R.; Quax, Wim J.; Janssen, Dick B.; Feringa, Ben L.; Poelarends, Gerrit J.

    2009-01-01

    3-Methylaspartate ammonia-lyase (MAL) catalyzes the reversible amination of mesaconate to give both (2S,3S)-3-methylaspartic acid and (2S,3R)-3-methylaspartic acid as products. The deamination mechanism of MAL is likely to involve general base catalysis, in which a catalytic base abstracts the C3 pr

  10. Biocatalytic Enantioselective Synthesis of N-Substituted Aspartic Acids by Aspartate Ammonia Lyase

    NARCIS (Netherlands)

    Weiner, Barbara; Poelarends, Gerrit J.; Janssen, Dick B.; Feringa, Ben L.

    2008-01-01

    The gene encoding aspartate ammonia lyase (aspB) from Bacillus sp. YM55-1 has been cloned and overexpressed, and the recombinant enzyme containing a C-terminal His6 tag has been purified to homogeneity and subjected to kinetic characterization. Kinetic studies have shown that the His6 tag does not a

  11. Strain Improvement of Rhodotorula graminis for Production of a Novel l-Phenylalanine Ammonia-Lyase

    OpenAIRE

    Orndorff, Steve A.; Costantino, Nina; Stewart, David; Durham, Don R.

    1988-01-01

    l-Phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) from Rhodotorula rubra has been used in the commercial manufacture of l-phenylalanine from trans-cinnamic acid. In this study, R. graminis PAL was investigated. Mutant strain GX6000 was isolated after ethyl methanesulfonate mutagenesis of wild-type R. graminis GX5007 by selecting for resistance to phenylpropiolic acid, an analog of trans-cinnamic acid. Mutant strain GX6000 produced inducible PAL at levels four- to fivefold higher than had wild-t...

  12. Probing Reversible Chemistry in Coenzyme B12-Dependent Ethanolamine Ammonia Lyase with Kinetic Isotope Effects

    OpenAIRE

    Rentergent, Julius; Scruton, Nigel S; Hay, Sam; Jones, Alex R.

    2015-01-01

    Coenzyme B12-dependent enzymes such as ethanolamine ammonia lyase have remarkable catalytic power and some unique properties that enable detailed analysis of the reaction chemistry and associated dynamics. By selectively deuterating the substrate (ethanolamine) and/or the β-carbon of the 5′-deoxyadenosyl moiety of the intrinsic coenzyme B12, it was possible to experimentally probe both the forward and reverse hydrogen atom transfers between the 5′-deoxyadenosyl radical and substrate duri...

  13. Highly Active and Specific Tyrosine Ammonia-Lyases from Diverse Origins Enable Enhanced Production of Aromatic Compounds in Bacteria and Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Jendresen, Christian Bille; Stahlhut, Steen Gustav; Li, Mingji;

    2015-01-01

    Phenylalanine and tyrosine ammonia-lyases form cinnamic acid and p-coumaric acid, which are precursors of a wide range of aromatic compounds of biotechnological interest. Lack of highly active and specific tyrosine ammonia-lyases has previously been a limitation in metabolic engineering approache...

  14. Characterization and differential expression analysis of artichoke phenylalanine ammonia-lyase-coding sequences.

    Science.gov (United States)

    De Paolis, Angelo; Pignone, Domenico; Morgese, Anita; Sonnante, Gabriella

    2008-01-01

    Sequences encoding phenylalanine ammonia-lyase were isolated from artichoke, by using a sequence homology strategy, by screening a genomic library and by 3'-rapid amplification of cDNA end (RACE) technology. These analyses and Southern blots suggested that, in artichoke, phenylalanine ammonia-lyase (PAL) is encoded by a small gene family. The sequences isolated from genomic DNA possess two exons and one intron at the conserved position as in most plant pal characterized to date. The 3'-RACE analysis also indicated that each member of the artichoke pal gene family was present as a pool of transcripts, different in the length of 3'-untranslated region. The deduced amino acid sequences were highly similar to those of PAL from lettuce and sunflower. One of the artichoke pal genes was completely sequenced, and its 5' upstream region contained TATA, CAAT box and cis regulatory elements identified in other phenylpropanoid pathway genes as playing a role in UV and elicitor induction. The expression of three of the identified artichoke pal sequences was evaluated in different plant parts, in developmental stages and after wounding, using gene-specific primers/probe combinations in real-time polymerase chain reaction assays. The three putative genes were differentially expressed in the plant parts analysed and were developmentally regulated. Moreover, after leaf mechanical injury, all of them were differentially regulated. The possible involvement of the single pal genes in different physiological processes is discussed. PMID:18251868

  15. Possible regulatory role of phenylalanine ammonia-lyase in the production of anthocyanins in asparagus (Asparagus officinalis L)

    NARCIS (Netherlands)

    Flores, F.B.; Oosterhaven, J.; Martinez-Madrid, M.C.; Romojaro, F.

    2005-01-01

    The regulatory role of phenylalanine ammonia-lyase (PAL) in the light-induced accumulation of anthocyanins in the epidermis of asparagus spears has been analysed. A correlation between the stimulation of PAL activity and the rise in total anthocyanin content has been observed. Light radiation induce

  16. Expression, crystallization and preliminary X-ray crystallographic study of ethanolamine ammonia-lyase from Escherichia coli

    International Nuclear Information System (INIS)

    Ethanolamine ammonia-lyase from E. coli has been overexpressed, purified and crystallized. The crystals diffracted to 2.2 Å resolution using synchrotron radiation. Ethanolamine ammonia-lyase (EAL) catalyzes the adenosylcobalamin-dependent conversion of ethanolamine to acetaldehyde and ammonia. The wild-type enzyme shows a very low solubility. N-terminal truncation of the Escherichia coli EAL β-subunit dramatically increases the solubility of the enzyme without altering its catalytic properties. Two deletion mutants of the enzyme [EAL(βΔ4–30) and EAL(βΔ4–43)] have been overexpressed, purified and crystallized using the sitting-drop vapour-diffusion method. Crystals of EAL(βΔ4–30) and EAL(βΔ4–43) diffracted to approximately 8.0 and 2.1 Å resolution, respectively

  17. Developmental and environmental regulation of a phenylalanine ammonia-lyase-beta-glucuronidase gene fusion in transgenic tobacco plants.

    OpenAIRE

    Liang, X W; Dron, M; J. Schmid; Dixon, R. A.; Lamb, C J

    1989-01-01

    A 1.1-kilobase promoter fragment of the bean (Phaseolus vulgaris L.) phenylalanine ammonia-lyase (EC 4.3.1.5) gene PAL2 was translationally fused to the beta-glucuronidase reporter gene and transferred to tobacco by Agrobacterium tumefaciens-mediated leaf disk transformation. The distribution of beta-glucuronidase activity in these transgenic plants is very similar to that of endogenous PAL2 transcripts in bean, with very high levels in petals; marked accumulation in anthers, stigmas, roots, ...

  18. Sunlight-stimulated phenylalanine ammonia-lyase (PAL) activity and anthocyanin accumulation in exocarp of ‘Mahajanaka’ mango

    OpenAIRE

    Kobkiat Saengnil

    2011-01-01

    The activity of phenylalanine ammonia-lyase (PAL) required for anthocyanin synthesis was stimulated by sunlight exposure resulting in the development of red colour in ‘Mahajanaka’ mango exocarp, which occurred only on the sunlight-exposed side of the fruit. The accumulation of anthocyanin was concurrent with the increase in PAL activity in the mature stage of the fruit. The exposed side of the fruit had higher PAL activity, endogenous sugar content, and anthocyanin accumulation than the unexp...

  19. Phenolics and Flavonoids Compounds, Phenylanine Ammonia Lyase and Antioxidant Activity Responses to Elevated CO2 in Labisia pumila (Myrisinaceae)

    OpenAIRE

    Jaafar, Hawa Z. E.; Ehsan Karimi; Mohd Hafiz Ibrahim

    2012-01-01

    A split plot 3 × 3 experiment was designed to examine the impact of three concentrations of CO2 (400, 800 and 1,200 µmol·mol−1) on the phenolic and flavonoid compound profiles, phenylalanine ammonia lyase (PAL) and antioxidant activity in three varieties of Labisia pumila Benth. (var. alata, pumila and lanceolata) after 15 weeks of exposure. HPLC analysis revealed ...

  20. Recombinant l-phenylalanine ammonia lyase from Rhodosporidium toruloides as a potential anticancer agent.

    Science.gov (United States)

    Babich, Olga O; Pokrovsky, Vadim S; Anisimova, Natalia Yu; Sokolov, Nikolai N; Prosekov, Alexander Yu

    2013-01-01

    The recombinant producer strain expressing Rhodosporidium toruloides l-phenylalanine ammonia lyase (PAL) has been obtained, and a purification procedure of PAL has been developed. The purified enzyme, PAL, has the following biochemical and catalytic characteristics: Km for l-Phe of 0.49 mM, pH optimum at 8.5, and temperature optimum at 50°C. PAL exhibited a significant cytotoxic effect toward the following cell lines: MCF7 (IC50 = 1.97 U/mL), DU145 (IC50 = 7.3 U/mL), which are comparable with E. coli l-asparaginase type-II cytotoxicity in vitro. Administration of PAL (200-400 U/kg) to L5178y-bearing mice for five times (a total dose of 1000-2000 U/kg) was well tolerated and showed the increase of life span (ILS) = 12-16%, P < 0.05. Data obtained suggest that PAL from R. toruloides has a potential for cancer treatment. PMID:23718781

  1. Molecular cloning and sequence analysis of a phenylalanine ammonia-lyase gene from dendrobium.

    Directory of Open Access Journals (Sweden)

    Qing Jin

    Full Text Available In this study, a phenylalanine ammonia-lyase (PAL gene was cloned from Dendrobium candidum using homology cloning and RACE. The full-length sequence and catalytic active sites that appear in PAL proteins of Arabidopsis thaliana and Nicotiana tabacum are also found: PAL cDNA of D. candidum (designated Dc-PAL1, GenBank No. JQ765748 has 2,458 bps and contains a complete open reading frame (ORF of 2,142 bps, which encodes 713 amino acid residues. The amino acid sequence of DcPAL1 has more than 80% sequence identity with the PAL genes of other plants, as indicated by multiple alignments. The dominant sites and catalytic active sites, which are similar to that showing in PAL proteins of Arabidopsis thaliana and Nicotiana tabacum, are also found in DcPAL1. Phylogenetic tree analysis revealed that DcPAL is more closely related to PALs from orchidaceae plants than to those of other plants. The differential expression patterns of PAL in protocorm-like body, leaf, stem, and root, suggest that the PAL gene performs multiple physiological functions in Dendrobium candidum.

  2. Control of phenylalanine ammonia-lyase gene promoters from pea by UV radiation

    International Nuclear Information System (INIS)

    The gene fusion system was used to study UV light-control of PS PAL1 and PS PAL2 genes encoding phenylalanine ammonia-lyase of pea. The induction of pea PAL promoters was analysed in transgenic tobacco plants. Binary plasmids (derivatives of pBI101.2 vector) containing 5' regulatory fragments of PS PAL1 and PS PAL2 linked to reporter genes (GUS, LUC) were constructed. The analyses were performed with the use of single constructs (containing one variant of PS PAL promoter and one reporter gene) and dual constructs (containing both PS PAL1 and PS PAL2 promoters connected with different reporter genes). The use of dual constructs enabled the evaluation of both PS PAL promoters activity in the same plant. The analyses of in vitro grown plants have shown that both PAL promoters are strongly induced in leaves subjected to UV radiation. In some cases, the UV-stimulated expression exceeded the exposed areas. This phenomenon was observed more often in the leaves of plants containing the PS PAL1::GUS than PS PAL2::GUS construct. Removal of boxes 2, 4, 5 from PS PAL1 promoter and deletion of its 5' end region (-339 to -1394) decreases the level of gene expression but does not eliminate its responsiveness to UV

  3. Genome-wide characterization of phenylalanine ammonia-lyase gene family in watermelon (Citrullus lanatus).

    Science.gov (United States)

    Dong, Chun-Juan; Shang, Qing-Mao

    2013-07-01

    Phenylalanine ammonia-lyase (PAL), the first enzyme in the phenylpropanoid pathway, plays a critical role in plant growth, development, and adaptation. PAL enzymes are encoded by a gene family in plants. Here, we report a genome-wide search for PAL genes in watermelon. A total of 12 PAL genes, designated ClPAL1-12, are identified . Nine are arranged in tandem in two duplication blocks located on chromosomes 4 and 7, and the other three ClPAL genes are distributed as single copies on chromosomes 2, 3, and 8. Both the cDNA and protein sequences of ClPALs share an overall high identity with each other. A phylogenetic analysis places 11 of the ClPALs into a separate cucurbit subclade, whereas ClPAL2, which belongs to neither monocots nor dicots, may serve as an ancestral PAL in plants. In the cucurbit subclade, seven ClPALs form homologous pairs with their counterparts from cucumber. Expression profiling reveals that 11 of the ClPAL genes are expressed and show preferential expression in the stems and male and female flowers. Six of the 12 ClPALs are moderately or strongly expressed in the fruits, particularly in the pulp, suggesting the potential roles of PAL in the development of fruit color and flavor. A promoter motif analysis of the ClPAL genes implies redundant but distinctive cis-regulatory structures for stress responsiveness. Finally, duplication events during the evolution and expansion of the ClPAL gene family are discussed, and the relationships between the ClPAL genes and their cucumber orthologs are estimated. PMID:23546528

  4. Structural and Functional Studies on Salmonella Typhimurium Ethanolamine Ammonia-Lyase

    Science.gov (United States)

    Bovell, Adonis

    Ethanolamine ammonia-lyase (EAL), a coenzyme-B12 (AdoCbl) dependent bacterial enzyme, catalyzes the deamination of select amino-alcohols by using a radical mechanism. Extensive high-resolution spectroscopic determinations of reactant intermediate-state structures and detailed kinetic and thermodynamic studies have been conducted for the Salmonella typhimurium enzyme. A statistically robust homology model for the full [(EutB-EutC) 2]3 oligomer of S. typhimurium EAL is constructed from the Escherichia coli crystal structure. This structure establishes a platform for detailed, microscopic interpretation of the molecular mechanism of EAL catalysis. The model is used to describe the hierarchy of EutB and EutC subunit interactions in the native oligomer and to guide a genetic and biochemical approach to the long-standing challenge of functional oligomer reconstitution from isolated subunits. The model is used to direct site-directed mutagenesis of EAL, leading to the creation of the EutB-F258W mutant, whose fluorescence is sensitive to the binding of AdoCbl. The AdoCbl-EAL dissociation constant is determined to be 1.2 microM, which places limits on the timescale of cofactor exchange kinetics. A series of cysteine-replaced mutants of EAL was created, and progress was made towards the goal of a mutant EAL for site-directed spin labeling studies. The primary cysteine attachment site in wild-type EAL for the 4-maleimido-TEMPO spin label was identified as EutC-C37. The localization of spin labels on EAL enables the interpretation of electron paramagnetic resonance (EPR) studies that probe distal effects on protein structure caused by cofactor binding. Previously determined rate constants for decay of the cryotrapped substrate radical, and kcat values at ambient temperature, for 1H- and 2H-labelled substrate, are united in a single model that describes the sequential radical rearrangement and hydrogen atom transfer steps, from 190 to 295 K. The model indicates that hydrogen

  5. Correlation of Rutin Accumulation with 3-O-Glucosyl Transferase and Phenylalanine Ammonia-lyase Activities During the Ripening of Tomato Fruit

    NARCIS (Netherlands)

    Capanoglu, E.; Beekwilder, J.; Matros, A.; Boyacioglu, D.; Hall, R.D.; Mock, H.P.

    2012-01-01

    In tomato, the predominant flavonoid is quercetin-3-rutinoside (rutin). In this study, we aim to investigate the phenylalanine ammonia-lyase (PAL) and the quercetin-3-O-glucosyl transferase (3-GT) reactions in the formation of rutin during tomato fruit ripening. Tomatoes of the Moneymaker variety at

  6. Preliminary structural investigations of the Eut-L shell protein of the ethanolamine ammonia-lyase metabolosome of Escherichia coli

    International Nuclear Information System (INIS)

    Preliminary X-ray analysis of crystals of the bacterial microcompartment shell protein Eut-L from Escherichia coli is reported. The ethanolamine ammonia-lyase microcompartment is composed of five different shell proteins that have been proposed to assemble into symmetrically shaped polyhedral particles of varying sizes. Here, preliminary X-ray analysis of crystals of the bacterial microcompartment shell protein Eut-L from Escherichia coli is reported. Cloning, overexpression and purification resulted in highly pure protein that crystallized readily under many different conditions. In all cases the protein forms thin hexagonal plate-shaped crystals belonging to space group P3 that are of unusually high stability against different solvent conditions. The crystals diffracted to a resolution of 2.0 Å using synchrotron radiation but proved to be radiation-sensitive. Preparations of heavy-atom-derivatized crystals for use in determining the three-dimensional structure are under way

  7. Production of Salicylic Acid Precursors Is a Major Function of Phenylalanine Ammonia-Lyase in the Resistance of Arabidopsis to Peronospora parasitica

    OpenAIRE

    Slusarenko, A. J.; Mauch-Mani, Brigitte

    2011-01-01

    Arabidopsis ecotype Columbia (Col-0) seedlings, transformed with a phenylalanine ammonia-lyase 1 promoter (PAL1)--glucuronidase (GUS) reporter construct, were inoculated with virulent and avirulent isolates of Peronospora parasitica. The PAL1 promoter was constitutively active in the light in vascular tissue but was induced only in the vicinity of fungal structures in the incompatible interaction. A double-staining procedure was developed to distinguish between GUS activity and fungal struct...

  8. Phenylalanine ammonia-lyase (pal) and peroxidase activity in brown rust infected tissues of pakistani wheat cultivars

    International Nuclear Information System (INIS)

    Besides other factors resistance and susceptibility is the outcome of biochemical processes such as activities of defense-related enzymes. So in this study, Phenylalanine ammonia-lyase (PAL) and Peroxidase activity of resistant (Inqilab-91) and susceptible (Kirin-95) wheat cultivars were determined through spectrophotometer to address the biochemical aspect related to the disease after 8 hours, 24 hours, 48 hours and 72 hours of leaf rust inoculation. The results have shown that these enzymes were present in both the resistant and susceptible cultivars but the activity was more pronounced in the resistant one. The effect of PAL and peroxidase activity was also investigated among inoculated and uninoculated plants within the same cultivar. The activity of both PAL and peroxidase were more significant in inoculated ones. The results have shown that the after 72 hours of inoculation Inqilab-91 had more PAL activity i.e., 5.47 IU/ml/min than in Kirin-95 i.e., 2.08 IU/ml/min at 270 nm. While peroxidase activity in Inqilab-91 was 6.41 IU/ml/min and in Kirin-95, 3.66 IU/ml/min after 72 hours of inoculation, observed under 470 nm wavelength. Increase in one's activity increases the other enzyme's activity. The activity was more prominent after 72 hours of infection as pathogen had successfully established itself in the host plant tissue. The activities of these enzymes act as plants active defense mechanism against the attack of pathogen. (author)

  9. Electrochemical sensing platform amplified with a nanobiocomposite of L-phenylalanine ammonia-lyase enzyme for the detection of capsaicin.

    Science.gov (United States)

    Sabela, Myalowenkosi I; Mpanza, Thabani; Kanchi, Suvardhan; Sharma, Deepali; Bisetty, Krishna

    2016-09-15

    The present study involves the development of a sensitive electrochemical biosensor for the determination of capsaicin extracted from chilli fruits, based on a novel signal amplification strategy using enzyme technology. For the first time, platinum electrode modified with multiwalled carbon nanotubes where phenylalanine ammonia-lyase enzyme was immobilized using nafion was characterized by attenuated total reflectance infrared spectroscopy, transmittance electron microscopy and thermo-gravimetric analysis supported by computational methods. Cyclic and differential pulse voltammetry measurements were performed to better understand the redox mechanism of capsaicin. The performance of the developed electrochemical biosensor was tested using spiked samples with recoveries ranging from 98.9 to 99.6%. The comparison of the results obtained from bare and modified platinum electrodes revealed the sensitivity of the developed biosensor, having a detection limit (S/N=3) of 0.1863µgmL(-1) and electron transfer rate constant (ks) of 3.02s(-1). Furthermore, adsorption and ligand-enzyme docking studies were carried out to better understand the redox mechanisms supported by density functional theory calculations. These results revealed that capsaicin forms hydrogen bonds with GLU355, GLU541, GLU586, ARG and other amino acids of the hydrophobic channel of the binding sites thereby facilitating the redox reaction for the detection of capsaicin. PMID:27104584

  10. Action spectrum for induction of promoter activity of phenylalanine ammonia-lyase gene by UV in carrot suspension cells

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Junko [Kyoto Univ., Agricultural Chemistry Dept., Kyoto (Japan); Ozeki, Yoshihiro [Tokyo Univ. of Agriculture and Technology, Biotechnology Dept., Tokyo (Japan); Yoshida, Kazuichi [Kyoto Univ., Botany Dept., Kyoto (Japan)

    1997-10-01

    The full-length promoter (-2335) of the carrot (Daucus carota) phenylalanine ammonia-lyase gene (gDcPALLI) fused to the luciferase reporter gene was transiently transformed to carrot protoplasts by electroporation, and the promoter activity induced by monochromatic UV light of various wavelengths was examined. The action spectrum constructed from the fluence-response curves showed a single peak at around 280 nm, suggesting that the activation of the gDcPALI promoter is categorizable as one of the UVB light responses. The same assay system was applied to variously truncated gDcPALI promoters and to CaMV35S promoter fusion with various parts 5` - upstream of the gDcPALI promoter. The region from -396 to -190 (relative to the transcription start site) fused to the CaMV35S core (-90) promoter showed a 280 nm-dominant responses. However, gDCPALI promoters truncated above -570 and -396, although they contain the region between -396 and -190, did not show such a typical UVB response, i.e. they responded to 260 nm light as much as to 280 nm light. The promoter truncated to below -190 also responded to 260 nm light as much as to 280 nm light. Therefore we assumed that the gDcPALI promoter is composed of three functionally different parts: the upstream above -570 (modulator), the region from -396 to -190 (UVB responsive) and the downstream below -190 (UVB and C responsive). The overall UVB response of the gDcPALI full-length promoter is explained as the result of interaction of these three components. (Author).

  11. Phenolics and flavonoids compounds, phenylanine ammonia lyase and antioxidant activity responses to elevated CO₂ in Labisia pumila (Myrisinaceae).

    Science.gov (United States)

    Jaafar, Hawa Z E; Ibrahim, Mohd Hafiz; Karimi, Ehsan

    2012-01-01

    A split plot 3 × 3 experiment was designed to examine the impact of three concentrations of CO₂ (400, 800 and 1,200 μmol·mol⁻¹) on the phenolic and flavonoid compound profiles, phenylalanine ammonia lyase (PAL) and antioxidant activity in three varieties of Labisia pumila Benth. (var. alata, pumila and lanceolata) after 15 weeks of exposure. HPLC analysis revealed a strong influence of increased CO₂ concentration on the modification of phenolic and flavonoid profiles, whose intensity depended on the interaction between CO₂ levels and L. pumila varieties. Gallic acid and quercetin were the most abundant phenolics and flavonoids commonly present in all the varieties. With elevated CO₂ (1,200 μmol·mol⁻¹) exposure, gallic acid increased tremendously, especially in var. alata and pumila (101-111%), whilst a large quercetin increase was noted in var. lanceolata (260%), followed closely by alata (201%). Kaempferol, although detected under ambient CO₂ conditions, was undetected in all varieties after exposure. Instead, caffeic acid was enhanced tremendously in var. alata (338~1,100%) and pumila (298~433%). Meanwhile, pyragallol and rutin were only seen in var. alata (810 μg·g⁻¹ DW) and pumila (25 μg·g⁻¹ DW), respectively, under ambient conditions; but the former compound went undetected in all varieties while rutin continued to increase by 262% after CO₂ enrichment. Interestingly, naringenin that was present in all varieties under ambient conditions went undetected under enrichment, except for var. pumila where it was enhanced by 1,100%. PAL activity, DPPH and FRAP also increased with increasing CO₂ levels implying the possible improvement of health-promoting quality of Malaysian L. pumila under high CO₂ enrichment conditions. PMID:22634843

  12. Induction of phenylalanine ammonia-lyase and lipoxygenase in cotton seedlings by mechanical wounding and aphid infestation

    Institute of Scientific and Technical Information of China (English)

    QIN Qiuju; SHI Xueyan; LIANG Pei; GAO Xiwu

    2005-01-01

    It has been suggested that infestation of plants causes increases in the activities of phenylalanine ammonia-lyase (PAL)and lipoxygenase (LOX), key enzymes in the phenolic compounds synthesis pathway and the octadecanoid pathway, respectively. The purpose of this work is to investigate whether the infestation of cotton aphid (Aphis gossypii ) and mechanical wound can cause the induction of PAL and LOX activities in cotton seedlings, and whether the induction occurs in healthy seedlings growing nearby the attacked ones. The specific activities of PAL and LOX were measured using spectrophotometric method after aphid infestation and mechanical wounding. Result indicated that PAL activity and LOX activity were greatly induced by mechanical wounding and aphid infestation in cotton seedlings. The induction of PAL and LOX occurred not only in wounded and infested seedlings but also in intact healthy seedlings growing nearby. After exposed to the aphid infestation-induced volatiles, the specific activity of PAL in cotton seedlings increased by 6 % at 24 h, 80 % at 48 h, 235 % at 72 h compared to the control, and the specific activity of LOX increased by 18 % at 24 h, 34 % at 48 h,24 % at 72 h, respectively. In comparison, the specific activity of PAL in unwounded seedlings exposed to wound-induced volatiles increased by 0.0 at 24 h, 200% at 48 h, 164% at 72 h, respectively and the specific activity of LOX increased by 28% at 24 h, 37% at 48 h, 8 % at 72 h, respectively. It suggests that the induced volatiles are involved in plant-plant communication as airborne transferred signals.

  13. Action spectrum for induction of promoter activity of phenylalanine ammonia-lyase gene by UV in carrot suspension cells

    International Nuclear Information System (INIS)

    The full-length promoter (-2335) of the carrot (Daucus carota) phenylalanine ammonia-lyase gene (gDcPALLI) fused to the luciferase reporter gene was transiently transformed to carrot protoplasts by electroporation, and the promoter activity induced by monochromatic UV light of various wavelengths was examined. The action spectrum constructed from the fluence-response curves showed a single peak at around 280 nm, suggesting that the activation of the gDcPALI promoter is categorizable as one of the UVB light responses. The same assay system was applied to variously truncated gDcPALI promoters and to CaMV35S promoter fusion with various parts 5' - upstream of the gDcPALI promoter. The region from -396 to -190 (relative to the transcription start site) fused to the CaMV35S core (-90) promoter showed a 280 nm-dominant responses. However, gDCPALI promoters truncated above -570 and -396, although they contain the region between -396 and -190, did not show such a typical UVB response, i.e. they responded to 260 nm light as much as to 280 nm light. The promoter truncated to below -190 also responded to 260 nm light as much as to 280 nm light. Therefore we assumed that the gDcPALI promoter is composed of three functionally different parts: the upstream above -570 (modulator), the region from -396 to -190 (UVB responsive) and the downstream below -190 (UVB and C responsive). The overall UVB response of the gDcPALI full-length promoter is explained as the result of interaction of these three components. (Author)

  14. Involvement of Carbohydrate, Protein and Phenylanine Ammonia Lyase in Up-Regulation of Secondary Metabolites in Labisia pumila under Various CO2 and N2 Level

    OpenAIRE

    Mohd Hafiz Ibrahim; Jaafar, Hawa Z. E.

    2011-01-01

    A split plot factorial 2 × 3 experiment was designed to examine and characterize the relationships among secondary metabolites (total phenolics, TP; total flavonoids, TF), carbohydrate content, C/N ratio, protein synthesis and L–phenylalanine ammonia lyase (PAL; EC 4.3.1.5) activity in the Malaysian medicinal herb Labisia pumila (Blume) Fern-Vill. under different CO2 concentrations (400 = ambient and 1,200 µmol mol−1 CO2) and three levels of nitrogen fertilization (0, 90 and 270 kg N ha−1) fo...

  15. Reduced Lignin Content and Altered Lignin Composition in Transgenic Tobacco Down-Regulated in Expression of L-Phenylalanine Ammonia-Lyase or Cinnamate 4-Hydroxylase.

    Science.gov (United States)

    Sewalt, VJH.; Ni, W.; Blount, J. W.; Jung, H. G.; Masoud, S. A.; Howles, P. A.; Lamb, C.; Dixon, R. A.

    1997-09-01

    We analyzed lignin content and composition in transgenic tobacco (Nicotiana tabacum) lines altered in the expression of the early phenylpropanoid biosynthetic enzymes L-phenylalanine ammonia-lyase and cinnamate 4-hydroxylase (C4H). The reduction of C4H activity by antisense expression or sense suppression resulted in reduced levels of Klason lignin, accompanied by a decreased syringyl/guaiacyl monomer ratio as determined by pyrolysis gas chromatography/mass spectrometry Similar reduction of lignin levels by down -regulation of L-phenylalanine ammonia-lyase, the enzyme preceding C4H in the central phenylpropanoid pathway, did not result in a decreased syringyl/guaiacyl ratio. Rather, analysis of lignin methoxyl content and pyrolysis suggested an increased syringyl/guaiacyl ratio. One possible explanation of these results is that monolignol biosynthesis from L-phenylalanine might occur by more than one route, even at the early stages of the core phenylpropanoid pathway, prior to the formation of specific monolignol precursors. PMID:12223790

  16. Cis-and Trans-Cinnamic Acids Have Different Effects on the Catalytic Properties of Arabidopsis Phenylalanine Ammonia Lyases PAL1, PAL2, PAL4

    Institute of Scientific and Technical Information of China (English)

    Ming-Jie CHEN; Veerappan VIJAYKUMAR; Bing-Wen LU; Bing XIA; Ning LI

    2005-01-01

    Cis-cinnamic acid (CA) is a naturally occurring compound, presumably converted from transCA in higher plants. To investigate the effect of cis-CA on the activity of Arabidopsis phenylalanine ammonia lyase (PAL), AtPAL1, AtPAL2, and AtPAL4 genes were isolated using reverse transcription polymerase chain reaction. These genes were fused to a glutathione S-transferase gene and overexpressed in a heterologous prokaryotic system of Escherichia coli. The purified PAL1, PAL2 and PAL4 enzymes were characterized biochemically to determine the effects of cis-CA on the kinetic parameter Km. The results showed that cis-CA is a competitive inhibitor for PAL1, but not PAL2 and PAL4, whereas trans-CA acts as a competitive inhibitor for all three PAL isomers, suggesting that cis- and trans-CA have different effects on the catalytic activity of PAL.

  17. Change in the Content of Salicylic Acid and in the Activities of Phenylalanine Ammonia-Lyase and Catalase in Wheat Seedling Roots Under the Effect of Azospirillum Lectins

    Directory of Open Access Journals (Sweden)

    Alen'kina S.A.

    2012-05-01

    Full Text Available We investigated the time course of changes in the endogenous content of salicylic acid, the ratio between the acid's free and bound forms, and changes in the activities of phenylalanine ammonia-lyase and catalase in wheat seedling roots under the effect of the lectins of two strains of the associative nitrogen-fixing bacterium Azospirillum: A. brasilense Sp7 and its mutant defective in lectin activity, A. brasilense Sp7.2.3. Differences in plant response to the action of the lectins from these two strains were established. On the basis of the obtained data, a model was proposed for lectin-assisted induction of resistance, according to which the lectin effect on the roots of seedlings results in accumulation of free salicylic acid, which inhibits catalase activity, ultimately leading to accumulation of hydrogen peroxide and to formation of induced resistance.

  18. Impact of Soil Field Water Capacity on Secondary Metabolites, Phenylalanine Ammonia-lyase (PAL), Maliondialdehyde (MDA) and Photosynthetic Responses of Malaysian Kacip Fatimah (Labisia pumila Benth)

    OpenAIRE

    Jaafar, Hawa Z. E.; Nur Farhana Mohamad Fakri; Mohd Hafiz Ibrahim

    2012-01-01

    A randomized complete block design 2 × 4 experiment was designed and conducted for 15 weeks to characterize the relationships between production of total phenolics, flavonoid, anthocyanin, leaf gas exchange, total chlorophyll, phenylalanine ammonia-lyase (PAL) and malondialdehyde (MDA) activity in two varieties of Labisia pumila Benth, namely the var. alata and pumila, under four levels of evapotranspiration replacement (ER) (100%...

  19. Phenylalanine Ammonia-Lyase-Catalyzed Deamination of an Acyclic Amino Acid: Enzyme Mechanistic Studies Aided by a Novel Microreactor Filled with Magnetic Nanoparticles.

    Science.gov (United States)

    Weiser, Diána; Bencze, László Csaba; Bánóczi, Gergely; Ender, Ferenc; Kiss, Róbert; Kókai, Eszter; Szilágyi, András; Vértessy, Beáta G; Farkas, Ödön; Paizs, Csaba; Poppe, László

    2015-11-01

    Phenylalanine ammonia-lyase (PAL), found in many organisms, catalyzes the deamination of l-phenylalanine (Phe) to (E)-cinnamate by the aid of its MIO prosthetic group. By using PAL immobilized on magnetic nanoparticles and fixed in a microfluidic reactor with an in-line UV detector, we demonstrated that PAL can catalyze ammonia elimination from the acyclic propargylglycine (PG) to yield (E)-pent-2-ene-4-ynoate. This highlights new opportunities to extend MIO enzymes towards acyclic substrates. As PG is acyclic, its deamination cannot involve a Friedel-Crafts-type attack at an aromatic ring. The reversibility of the PAL reaction, demonstrated by the ammonia addition to (E)-pent-2-ene-4-ynoate yielding enantiopure l-PG, contradicts the proposed highly exothermic single-step mechanism. Computations with the QM/MM models of the N-MIO intermediates from L-PG and L-Phe in PAL show similar arrangements within the active site, thus supporting a mechanism via the N-MIO intermediate. PMID:26345352

  20. Rhodotorula glutinis Phenylalanine/Tyrosine Ammonia Lyase Enzyme Catalyzed Synthesis of the Methyl Ester of para-Hydroxycinnamic Acid and its Potential Antibacterial Activity

    Science.gov (United States)

    MacDonald, Marybeth C.; Arivalagan, Pugazhendhi; Barre, Douglas E.; MacInnis, Judith A.; D’Cunha, Godwin B.

    2016-01-01

    Biotransformation of L-tyrosine methyl ester (L-TM) to the methyl ester of para- hydroxycinnamic acid (p-HCAM) using Rhodotorula glutinis yeast phenylalanine/tyrosine ammonia lyase (PTAL; EC 4.3.1.26) enzyme was successfully demonstrated for the first time; progress of the reaction was followed by spectrophotometric determination at 315 nm. The following conditions were optimized for maximal formation of p-HCAM: pH (8.5), temperature (37°C), speed of agitation (50 rpm), enzyme concentration (0.080 μM), and substrate concentration (0.50 mM). Under these conditions, the yield of the reaction was ∼15% in 1 h incubation period and ∼63% after an overnight (∼18 h) incubation period. The product (p-HCAM) of the reaction of PTAL with L-TM was confirmed using Nuclear Magnetic Resonance spectroscopy (NMR). Fourier Transform Infra-Red spectroscopy (FTIR) was carried out to rule out potential hydrolysis of p-HCAM during overnight incubation. Potential antibacterial activity of p-HCAM was tested against several strains of Gram-positive and Gram-negative bacteria. This study describes a synthetically useful transformation, and could have future clinical and industrial applications. PMID:27014206

  1. Efficient preparation of enantiopure D-phenylalanine through asymmetric resolution using immobilized phenylalanine ammonia-lyase from Rhodotorula glutinis JN-1 in a recirculating packed-bed reactor.

    Directory of Open Access Journals (Sweden)

    Longbao Zhu

    Full Text Available An efficient enzymatic process was developed to produce optically pure D-phenylalanine through asymmetric resolution of the racemic DL-phenylalanine using immobilized phenylalanine ammonia-lyase (RgPAL from Rhodotorula glutinis JN-1. RgPAL was immobilized on a modified mesoporous silica support (MCM-41-NH-GA. The resulting MCM-41-NH-GA-RgPAL showed high activity and stability. The resolution efficiency using MCM-41-NH-GA-RgPAL in a recirculating packed-bed reactor (RPBR was higher than that in a stirred-tank reactor. Under optimal operational conditions, the volumetric conversion rate of L-phenylalanine and the productivity of D-phenylalanine reached 96.7 mM h⁻¹ and 0.32 g L⁻¹ h⁻¹, respectively. The optical purity (eeD of D-phenylalanine exceeded 99%. The RPBR ran continuously for 16 batches, the conversion ratio did not decrease. The reactor was scaled up 25-fold, and the productivity of D-phenylalanine (eeD>99% in the scaled-up reactor reached 7.2 g L⁻¹ h⁻¹. These results suggest that the resolution process is an alternative method to produce highly pure D-phenylalanine.

  2. Impact of soil field water capacity on secondary metabolites, phenylalanine ammonia-lyase (PAL), maliondialdehyde (MDA) and photosynthetic responses of Malaysian kacip fatimah (Labisia pumila Benth).

    Science.gov (United States)

    Jaafar, Hawa Z E; Ibrahim, Mohd Hafiz; Mohamad Fakri, Nur Farhana

    2012-01-01

    A randomized complete block design 2 × 4 experiment was designed and conducted for 15 weeks to characterize the relationships between production of total phenolics, flavonoid, anthocyanin, leaf gas exchange, total chlorophyll, phenylalanine ammonia-lyase (PAL) and malondialdehyde (MDA) activity in two varieties of Labisia pumila Benth, namely the var. alata and pumila, under four levels of evapotranspiration replacement (ER) (100%; well watered), (75%, moderate water stress), (50%; high water stress) and (25%; severe water stress). The production of total phenolics, flavonoids, anthocyanin, soluble sugar and relative leaf water content was affected by the interaction between varieties and SWC. As the ER levels decreased from 100% to 25%, the production of PAL and MDA activity increased steadily. At the highest (100%) ER L. pumila exhibited significantly higher net photosynthesis, apparent quantum yield, maximum efficiency of photosystem II (f(v)/f(m)) and lower dark respiration rates compared to the other treatment. The production of total phenolics, flavonoids and anthocyanin was also found to be higher under high water stress (50% ER replacement) compared to severe water stress (25% ER). From this study, it was observed that as net photosynthesis, apparent quantum yield and chlorophyll content were downregulated under high water stress the production of total phenolics, flavonoids and anthocyanin were upregulated implying that the imposition of high water stress can enhance the medicinal properties of L. pumila Benth. PMID:22695235

  3. Isolation and Functional Characterization of a Phenylalanine Ammonia-Lyase Gene (SsPAL1 from Coleus (Solenostemon scutellarioides (L. Codd

    Directory of Open Access Journals (Sweden)

    Qinlong Zhu

    2015-09-01

    Full Text Available Phenylalanine ammonia-lyase (PAL is the first enzyme involved in the phenylpropanoid pathway and plays important roles in the secondary metabolisms, development and defense of plants. To study the molecular function of PAL in anthocyanin synthesis of Coleus (Solenostemon scutellarioides (L. Codd, a Coleus PAL gene designated as SsPAL1 was cloned and characterized using a degenerate oligonucleotide primer PCR and RACE method. The full-length SsPAL1 was 2450 bp in size and consisted of one intron and two exons encoding a polypeptide of 711 amino acids. The deduced SsPAL1 protein showed high identities and structural similarities with other functional plant PAL proteins. A series of putative cis-acting elements involved in transcriptional regulation, light and stress responsiveness were found in the upstream regulatory sequence of SsPAL1. Transcription pattern analysis indicated that SsPAL1 was constitutively expressed in all tissues examined and was enhanced by light and different abiotic factors. The recombinant SsPAL1 protein exhibited high PAL activity, at optimal conditions of 60 °C and pH 8.2. Although the levels of total PAL activity and total anthocyanin concentration have a similar variation trend in different Coleus cultivars, there was no significant correlation between them (r = 0.7529, p > 0.1, suggesting that PAL was not the rate-limiting enzyme for the downstream anthocyanin biosynthetic branch in Coleus. This study enables us to further understand the role of SsPAL1 in the phenylpropanoid (flavonoids, anthocyanins biosynthesis in Coleus at the molecular level.

  4. Involvement of Carbohydrate, Protein and Phenylanine Ammonia Lyase in Up-Regulation of Secondary Metabolites in Labisia pumila under Various CO2 and N2 Level

    Directory of Open Access Journals (Sweden)

    Mohd Hafiz Ibrahim

    2011-05-01

    Full Text Available A split plot factorial 2 × 3 experiment was designed to examine and characterize the relationships among secondary metabolites (total phenolics, TP; total flavonoids, TF, carbohydrate content, C/N ratio, protein synthesis and L–phenylalanine ammonia lyase (PAL; EC 4.3.1.5 activity in the Malaysian medicinal herb Labisia pumila (Blume Fern-Vill. under different CO2 concentrations (400 = ambient and 1,200 µmol mol−1 CO2 and three levels of nitrogen fertilization (0, 90 and 270 kg N ha−1 for 15 weeks. The interaction between CO2 and nitrogen levels imposed a significant impact on plant secondary metabolite production, protein, PAL activity and fructose levels. Highest TP and TF were recorded under 1,200 µmol mol−1 CO2 when N fertilizer was not applied; lowest values were obtained at 400 µmol mol−1 CO2 fertilized with the highest N level. Concurrently, fructose contents increased tremendously. Increase in fructose content might also enhance erythose-4-phosphate production (substrate for lignin and phenolic compounds, which shares a common precursor transdalolase in the pentose phosphate pathway. PAL activity was noted to be highest under 1,200 µmol mol−1 CO2 + 0 kg N ha−1 coinciding with subsequent recording of the lowest protein content. The results implied that the increase in plant secondary metabolites production under the tested conditions might be due to diversion of phenylalanine for protein synthesis to production of secondary metabolites. It was also found that the sucrose to starch ratio was also high under high levels of nitrogen fertilization, indicating an enhanced sucrose phosphate synthase activity (SPS; EC 2.4.1.14 under such condition.

  5. A rationale for autoinduction of a transcriptional activator: ethanolamine ammonia-lyase (EutBC) and the operon activator (EutR) compete for adenosyl-cobalamin in Salmonella typhimurium.

    OpenAIRE

    Sheppard, D E; Roth, J R

    1994-01-01

    The ethanolamine utilization (eut) operon of Salmonella typhimurium is controlled by a positive regulatory protein (EutR) which stimulates eut operon expression in response to the simultaneous presence of two effectors, ethanolamine and adenosyl-cobalamin (Ado-B12). Ado-B12 is a cofactor for ethanolamine ammonia-lyase (lyase), the first enzyme in the ethanolamine-degradative pathway. The dependence of this pathway on the use of Ado-B12 as an effector in eut operon induction may be explained b...

  6. Phenolics and Flavonoids Compounds, Phenylanine Ammonia Lyase and Antioxidant Activity Responses to Elevated CO2 in Labisia pumila (Myrisinaceae

    Directory of Open Access Journals (Sweden)

    Hawa Z.E. Jaafar

    2012-05-01

    Full Text Available A split plot 3 × 3 experiment was designed to examine the impact of three concentrations of CO2 (400, 800 and 1,200 µmol·mol−1 on the phenolic and flavonoid compound profiles, phenylalanine ammonia lyase (PAL and antioxidant activity in three varieties of Labisia pumila Benth. (var. alata, pumila and lanceolata after 15 weeks of exposure. HPLC analysis revealed a strong influence of increased CO2 concentration on the modification of phenolic and flavonoid profiles, whose intensity depended on the interaction between CO2 levels and L. pumila varieties. Gallic acid and quercetin were the most abundant phenolics and flavonoids commonly present in all the varieties. With elevated CO2 (1,200 µmol·mol−1 exposure, gallic acid increased tremendously, especially in var. alata and pumila (101–111%, whilst a large quercetin increase was noted in var. lanceolata (260%, followed closely by alata (201%. Kaempferol, although detected under ambient CO2 conditions, was undetected in all varieties after exposure. Instead, caffeic acid was enhanced tremendously in var. alata (338~1,100% and pumila (298~433%. Meanwhile, pyragallol and rutin were only seen in var. alata (810 µg·g−1 DW and pumila (25 µg·g−1 DW, respectively, under ambient conditions; but the former compound went undetected in all varieties while rutin continued to increase by 262% after CO2 enrichment. Interestingly, naringenin that was present in all varieties under ambient conditions went undetected under enrichment, except for var. pumila where it was enhanced by 1,100%. PAL activity, DPPH and FRAP also increased with increasing CO2 levels implying the possible improvement of health-promoting quality of Malaysian L. pumila

  7. Phenylalanin Ammonia-lyase Activity,Total Phenolics and Flavonoids Contents in Flowers,Leaves ,Hulls and Kernels of Three Pistachio(Pistacia vera L.) Cultivars%Phenylalanin Ammonia-lyase Activity,Total Phenolics and Flavonoids Contents in Flowers,Leaves,Hulls and Kernels of Three Pistachio(Pistacia vera L.) Cultivars

    Institute of Scientific and Technical Information of China (English)

    Nadernejad Nazi; Ahmadimoghadam Ali; Hosseinifard Javad; Pourseyedi Shahram

    2012-01-01

    Phenylalanin ammonia-lyase (PAL) plays a pivotal role in the production of phenolic compounds,which are responsible for the success of the defense strategies in harsh environments in response to different stimuli.Measurements of the PAL activity,total phenolics,total flavonoids and anthocyanin contents were performed in flowers,leaves and fruits of three pistachio cultivars "Ahmadaghaii","Ohadi" and "Kallehghuchi".The results showed that PAL activity was different in cultivars and in plant organs of pistachio trees (flowers,leaves and fruits).The highest activity rate of their compounds was observed in Ahmadaghaii cultivar.A positive correlation was observed between PAL activity,total phenolics and total flavonoids in leaves,and a negative correlation between PAL activity and anthocyanin contents in leaves and flowers of Ahmadaghaii cultivar.PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began.It is suggested that the hulls of the pistachio fruits,containing high level of phenolic compounds ( especially in Ahmadaghaii cultivar),may function as a protective layer of defense chemicals againstultraviolet radiation and pathogens.The final concentration of phenolic compounds,flavonoids and antocyanins in the kernel depend on PAL activity in the kernel' s cultivar.The results led to the conclusion that increase in PAL activity,phenolic compounds and flavonoids in Ahmadaghaii can help the plant to cope with the stresses better than the other cultivars.Since phenolic compounds are antioxidant and scavenge free oxygen,it is postulated that Ahmadaghaii is the most resistant cultivar to the environmental stresses.

  8. Hydrogen Peroxide Treatment and the Phenylpropanoid Pathway Precursors Feeding Improve Phenolics and Antioxidant Capacity of Quinoa Sprouts via an Induction of L-Tyrosine and L-Phenylalanine Ammonia-Lyases Activities

    Directory of Open Access Journals (Sweden)

    Michał Świeca

    2016-01-01

    Full Text Available Hydrogen peroxide treatment and the phenylpropanoid pathway precursors feeding affected the antioxidant capacity of quinoa sprouts. Compared to the control, total phenolics content was significantly increased by treatment of control sprouts with 50 mM and 200 mM H2O2—an elevation of about 24% and 28%, respectively. The highest increase of flavonoids content was found for the sprouts treated with 200 mM H2O2 obtained from seeds fed with shikimic acid. All the studied modifications increased the antioxidant potential of sprouts (at least by 50% compared to control. The highest reducing power was found for the sprouts treated with 200 mM H2O2 obtained by phenylalanine feeding (5.03 mg TE/g DW and those obtained from the seeds fed with tyrosine (5.26 mg TE/g DW. The activities of L-tyrosine (TAL and L-phenylalanine (PAL ammonia-lyases were strongly affected by germination time as well as the applied modification of sprouting. On the 3rd day the highest PAL activity was determined for both untreated and induced with 50 mM H2O2 sprouts obtained by phenylalanine feeding. H2O2 induced TAL activity; the highest TAL activity was determined for 3-day-old sprouts induced with 200 mM H2O2 obtained from seeds fed with phenylalanine.

  9. 4种竹子木质素合成酶PAL的基因克隆和序列分析%Gene Cloning and Sequence Analysis of Phenylalanine Ammonia-Lyase in Bamboo Lignin Synthase

    Institute of Scientific and Technical Information of China (English)

    李潞滨; 刘蕾; 张淑萍; 何聪芬; 胡桃; 庄彩云

    2009-01-01

    苯丙氨酸解氨酶(Phenylalanine Ammonia-Lyase,PAL;EC 4.3.1.5)是木质素生物合成过程的关键酶和限速酶.应用RACE(Rapid-Amplification of cDNA Ends)方法,获得了白哺鸡竹(Phyllostachys dulcis)、高节竹(Phyllostachys prominens)、龙鳞竹(Phyllostachys pubescens heterocycla)、丽水苦竹(Pleioblastus maculosoides Wen)等4种竹子PAL基因的全长序列,并进行了生物信息学分析.结果表明,PAL基因的开放读码框长度为2 136 bp,共编码712个氨基酸,具有2个外显子和1个内含子.其中高节竹、龙鳞竹、丽水苦竹PAL基因内含子长度为121 bp,白哺鸡竹PLA基因内含子长度为84 bp.推测其氨基酸序列,并分析PAL蛋白单体的三维结构,结果显示PAL蛋白均含有大量的α螺旋和β折叠结构.基于邻接法的进化树对31个物种的PAL基因的氨基酸序列分析表明,竹类植物PAL基因的保守性较高,与禾本科植物玉米、甘蔗的亲缘关系较近,与双子叶植物辣椒等的亲缘关系较远.%Phenylalanine Ammonia-Lyase (PAL EC 4.3.1.5) is one of the key enzymes in the process of lignin synthesis.In this paper,PAL gene sequences from four varieties of bamboo:Phyllostachys dulcis,Phyllostachys prominens,Phyllostachys pubescens heterocycla and Pleioblastus maculosoides Wen,were obtained by Rapid-Amplification of cDNA Ends (RACE).The results show that each PAL gene has two exons and an intron and every Open Reading Frame (ORF) is 2 136 bp in length,encoding 712 amino acids.The bamboo PAL amino acid sequences and threedimensional structures were then analyzed and inferred.The results indicate that all of the PAL proteins contain a large number of α-helix and β plated sheet structure.The neighbor-joining phylogenetic tree based on PAL sequences of bamboo and other 27 plants indicates that PAL gene sequence in bamboo is relatively conservative,and bamboo has a very close relationship with that of Zea may and Saccharum officinarum,and a remote relationship with

  10. Activities of lipoxygenase and phenylalanine ammonia lyase in poplar leaves induced by insect herbivory and volatiles%昆虫取食和挥发物诱导的杨树叶片中LOX和PAL活性变化

    Institute of Scientific and Technical Information of China (English)

    胡增辉; 张雯; 沈应柏; 付怀军; 苏晓华

    2009-01-01

    为了探索昆虫取食诱导的木本植物体内所产生的防御反应,以合作杨(Populus simonii×P.pyramidalis,'Opera 8277')扦插苗为实验材料,经杨扇舟蛾(Clostera anachoreta)幼虫取食后,检测叶片中茉莉酸(jasmonate,JA)途径中的关键酶--脂氧合酶(lipoxygenas,LOX)及苯基丙酸类合成途径中的限速酶--苯丙氨酸解氨酶(phenylalanine ammonia lyase,PAL)的活性变化.结果显示,LOX和PAL的活性不仅在虫咬叶片中出现增加,在虫咬叶片上部的系统叶片中也有显著升高,表明茉莉酸途径和苯基丙酸类合成途径被激活,而且防御反应被系统性诱导.并且,与虫咬植株邻近的健康杨树叶片中LOX和PAL的增加表明,杨树间存在由昆虫取食诱导挥发物介导的信息传递.熏蒸实验也证明,茉莉酸甲酯(methyl jasmonate,MeJA)能够作为气体信号诱导合作杨植株产生防御反应.

  11. Impact of Soil Field Water Capacity on Secondary Metabolites, Phenylalanine Ammonia-lyase (PAL, Maliondialdehyde (MDA and Photosynthetic Responses of Malaysian Kacip Fatimah (Labisia pumila Benth

    Directory of Open Access Journals (Sweden)

    Hawa Z. E. Jaafar

    2012-06-01

    Full Text Available A randomized complete block design 2 × 4 experiment was designed and conducted for 15 weeks to characterize the relationships between production of total phenolics, flavonoid, anthocyanin, leaf gas exchange, total chlorophyll, phenylalanine ammonia-lyase (PAL and malondialdehyde (MDA activity in two varieties of Labisia pumila Benth, namely the var. alata and pumila, under four levels of evapotranspiration replacement (ER (100%; well watered, (75%, moderate water stress, (50%; high water stress and (25%; severe water stress. The production of total phenolics, flavonoids, anthocyanin, soluble sugar and relative leaf water content was affected by the interaction between varieties and SWC. As the ER levels decreased from 100% to 25%, the production of PAL and MDA activity increased steadily. At the highest (100% ER L. pumila exhibited significantly higher net photosynthesis, apparent quantum yield, maximum efficiency of photosystem II (fv/fm and lower dark respiration rates compared to the other treatment. The production of total phenolics, flavonoids and anthocyanin was also found to be higher under high water stress (50% ER replacement compared to severe water stress (25% ER. From this study, it was observed that as net photosynthesis, apparent quantum yield and chlorophyll content were downregulated under high water stress the production of total phenolics, flavonoids and anthocyanin were upregulated implying that the imposition of high water stress can enhance the medicinal properties of L. pumila Benth.

  12. Expression of Astragalus membranaceus phenylalanine ammonia-lyase gene in Pichia pastoris%膜荚黄芪苯丙氨酸解氨酶基因在毕赤酵母中的分泌表达

    Institute of Scientific and Technical Information of China (English)

    张健慧; 王首锋

    2014-01-01

    L-phenylalanine , as an essential amino acid for human nutrition , is widely used in pharmaceutical and food industries . Using phenylalanine ammonia-lyase ( PAL ,EC 4 .3 .1 .5) to produce L-phenylalanine is one of the major routes . However , most commercial enzymes are extracted from Rhodotorula glutinis , which is time-consuming and over-priced . Therefore , how to efficiently construct the genetic engineering strain to produce PAL is the hot topic . Pichia pastoris is popular in expressing heterologous proteins due to the advantages of low nutritional demands , excellent genetic stability and high-density fermentation . Inserting the heterologous gene into pPIC 9K vectortoachievesecretedexpressionin P.pastorishasbeenreported.However,unlikeothervectors,pPIC9Khas few desirable restriction enzyme cutting sites , which reduces vector construction efficiency when the classical method of digestion and then ligation is adopted . Under this condition , an efficient cloning strategy , independent of digestion and ligation , is required . Homologous recombination in vitro between pPIC9K and gene can settle this problem .Now ,we intend to employ homologous recombination in vitro cloning method to insert the PAL gene into pPIC9K vector to obtain secreted expression in P . pastoris in order to lay the basis for industrial fermentation . First , total RNA extracted from Astragalus membranaceus was used as template for isolating cDNA . Open reading frame ( ORF) of PA L gene was amplified by PCR from cDNA with a pair of primers designed according to the sequence of PA L gene published in the GenBank . Then , ORF was cloned into vector pUCm-T . The transformant was selected to sequence for further analysis of the PA L gene sequence with the help of bioinformatics tools . After that , pPIC9K-PA L was constructed by homologous recombination in vitro . Similarly , the transformant was selected to sequence to investigate the base mutation caused by PCR . Linearized pPIC 9K-PA L by

  13. INDUCCIÓN DE FENILALANINA AMONIO LIASA Y VARIACIÓN EN EL CONTENIDO DE COMPUESTOS FENÓLICOS EN FRUTOS DE LULO (Solanum quitoense Lam INFECTADOS CON Colletotrichum acutatum. Induction of phenylalanine ammonia lyase and variation in phenolic compounds content in Lulo fruits (Solanum quitoense Lam infected by Colletotrichum acutatum

    Directory of Open Access Journals (Sweden)

    MAIRA ANDREA ARRIETA-GUEVARA

    Full Text Available Se evaluó la dinámica de la actividad fenilalanina amonio liasa (PAL en corteza de frutos de lulo (Solanum quitoense Lam con el fin de determinar su participación en respuestas bioquímicas hacia Colletotrichum acutatum. Se establecieron como mejores condiciones para la extracción de la enzima, buffer ácido bórico-borato de sodio 0.1M pH 8.8, 1% SDS, 3% PVPP y para medir la actividad, sustrato L-fenilalanina 5 mM , pH 8,0, 20°C , 30 ΜL de extracto y 45 min. Se realizó un ensayo in vivo usando frutos en tres estados de madurez, los cuales fueron inoculados con el patógeno o tratados con agua estéril. A cinco tiempos (hpi = horas post-infección se determinó la actividad PAL y el contenido total de fenoles, encontrándose que hay una respuesta diferencial de la enzima por efecto del patógeno y por el estado de madurez. Para frutos en el estado pintón se obtuvo el mayor aumento de PAL, el que perduró hasta 48 hpi, al compararlo con los controles y con los otros dos estados de madurez. Este aumento mostró relación con un marcado incremento en el contenido total de fenoles y con el desarrollo más tardío de síntomas característicos de antracnosis, observado para los frutos pintones. Estos resultados permiten postular, una posible relación positiva entre inducción de PAL, aumento de fenólicos y respuesta de tolerancia a C. acutatum. Para lulos en estado verde y maduro se observó aumento de PAL a 12 y 24 hpi que coincidió también con incremento en el contenido de fenoles totales, aunque para estos dos últimos estados dicho contenido disminuyó significativamente a tiempos mayores.Phenylalanine ammonia lyase (PAL activity induction was evaluated in lulo fruits to determine the role of this enzyme in biochemical responses towards the pathogen Colletotrichum acutatum. We studied the experimental conditions to obtain the enzyme, using lulo peel, and found that the best conditions for extraction were buffer of boric acid

  14. 葡萄苯丙氨酸解氨酶基因家族的全基因组鉴定及表达分析%Genome-wide characterization and expression analysis of the phenylalanine ammonia-lyase gene family in grapevine (Vitis vinifera L.)

    Institute of Scientific and Technical Information of China (English)

    孙润泽; 张雪; 成果; 李强; 朱燕溶; 陈武; 潘秋红; 段长青; 王军

    2016-01-01

    Phenylalanine ammonia-lyase (PAL), the first enzyme in the phenylpropanoid pathway, plays critical roles in plant growth, development and resistance to biotic/abiotic stresses. In this research, a total of 17 PAL genes were identified from the Vitis vinifera reference genome by the bioinformatics methods. Thirteen of the VviPAL genes are arranged in tandem in two duplication blocks located on chromosomes 11 and 16, the rests are randomly distributed on other chromosomes. Phylogenetic tree analysis revealed that most of the VviPAL members have a closer relationship with PALs from other dicots species, whereas the four VviPALs arranged in tandem on chromosome 11, which classified into neither the dicot nor monocot group, may serve as ancestral PALs in plants. The full-length cDNA of five VviPAL genes were isolated from ‘Cabernet Sauvignon’ according to the reference transcriptome of ‘Cabernet Sauvignon’ grape berries. Sequence analysis of the deduced VviPAL proteins showed that all of them contain conserved functional domains, confirming that these VviPALs may have similar functions with PALs from other plant species. Expression profiling reveals that VviPAL2 and VviPAL15 were strongly expressed in all test organs/tissues, and their expression throughout berry development was positively correlated with the accumulation of phenolic compounds. Furthermore, the transcripts of VviPAL2, VviPAL4 and VviPAL7 in grape berries were induced by cluster sunlight exposure and suppressed by cluster shading, which might contribute to changes in metabolites accumulation.%苯丙氨酸解氨酶(PAL)作为苯丙烷途径的入口酶,与植物生长发育以及生物和非生物胁迫响应等生物过程密切相关。本研究通过生物信息学方法,在已测序的葡萄基因组中预测得到17个PAL基因,其中13个串联分布在第11和16号染色体的2个重复基因群中,4个随机分布于其他染色体。系统发育树分析表明,葡萄大部分PAL基因与

  15. Metabolism of β-valine via a CoA-dependent ammonia lyase pathway

    NARCIS (Netherlands)

    Otzen, Marleen; Crismaru, Ciprian G.; Postema, Christiaan P.; Wijma, Hein J.; Heberling, Matthew M.; Szymanski, Wiktor; de Wildeman, Stefaan; Janssen, Dick B.

    2015-01-01

    Pseudomonas species strain SBV1 can rapidly grow on medium containing β-valine as a sole nitrogen source. The tertiary amine feature of β-valine prevents direct deamination reactions catalyzed by aminotransferases, amino acid dehydrogenases, and amino acid oxidases. However, lyase- or aminomutase-me

  16. Gamma irradiation induced enhancement of phenylalanine ammonia-lyase (PAL) and antioxidant activity in peach (Prunus persica Bausch, Cv. Elberta)

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Peerzada R., E-mail: hussainpr@rediffmail.co [Nuclear Research Laboratory, Bhabha Atomic Research Centre, Zakura, Srinagar 190006, Kashmir (India); Wani, Ali M.; Meena, Raghuveer S.; Dar, Mohd A. [Nuclear Research Laboratory, Bhabha Atomic Research Centre, Zakura, Srinagar 190006, Kashmir (India)

    2010-09-15

    Effect of medium dose gamma irradiation on PAL and antioxidant activity of peach fruit was investigated. Peach fruit after harvest at commercial maturity was irradiated in the dose range 1.0-2.0 kGy, stored under refrigerated conditions (3{+-}1 {sup o}C, RH 80%) and evaluated at intervals of 7 days. The antioxidant activity as determined by DPPH and FRAP methods revealed significant (p{<=}0.05) increase particularly in the dose range 1.6-2.0 kGy. During storage, maximum increase in both PAL and antioxidant activity was observed after 21 days. Positive correlation (r=0.75) existed between antioxidant activity and total phenols. EC{sub 50} values as obtained from DPPH and FRAP experiments were significantly (p{<=}0.05) lower in irradiated fruits compared to control.

  17. Gamma irradiation induced enhancement of phenylalanine ammonia-lyase (PAL) and antioxidant activity in peach (Prunus persica Bausch, Cv. Elberta)

    International Nuclear Information System (INIS)

    Effect of medium dose gamma irradiation on PAL and antioxidant activity of peach fruit was investigated. Peach fruit after harvest at commercial maturity was irradiated in the dose range 1.0-2.0 kGy, stored under refrigerated conditions (3±1 oC, RH 80%) and evaluated at intervals of 7 days. The antioxidant activity as determined by DPPH and FRAP methods revealed significant (p≤0.05) increase particularly in the dose range 1.6-2.0 kGy. During storage, maximum increase in both PAL and antioxidant activity was observed after 21 days. Positive correlation (r=0.75) existed between antioxidant activity and total phenols. EC50 values as obtained from DPPH and FRAP experiments were significantly (p≤0.05) lower in irradiated fruits compared to control.

  18. Cloning and Sequence Analysis of Phenylalanine Ammonia-lyase(PAL)Gene from Fagopyrum esculentum%甜荞苯丙氨酸解氨酶基因PAL的克隆及序列分析

    Institute of Scientific and Technical Information of China (English)

    李成磊; 蒙华; 张晓伟; 陈惠; 邵继荣; 吴琦

    2011-01-01

    利用RT-PCR技术,首次从甜荞(Fagopyrum esculentum)中克隆得到苯丙氨酸解氨酶基因(PAL)的cDNA ORF序列,命名为FePAL.该序列长2169bp,编码722个氨基酸,与其他植物PAL基因同源性较高,为80%~97%,其推导的氨基酸序列含有PAL酶活性中心特征序列GTITASGDLVPLSYIA和多个脱氨基、催化活性位点.系统发育树表明,甜养PAL基因与苦荞PAL基因聚类关系最近.

  19. 银杏叶苯丙氨酸解氨酶分离纯化条件的研究%Study on the Conditions of Isolating and Purifying L-phenylalanine Ammonia-lyase (PAL) in Ginkgo biloba Leaves

    Institute of Scientific and Technical Information of China (English)

    刘卫红; 王燕; 杜何为; 程水源

    2004-01-01

    对银杏(Ginkgo biloba)叶中苯丙氨酸解氨酶(PAL)的分离纯化条件进行了研究.离子交换条件优化的研究结果是最适洗脱缓冲液的pH8.9,最佳洗脱离子浓度(NaCl)为0.3 mol*L-1.经过一系列的分离纯化,蛋白质得率为0.35%,酶的得率为1.17%,纯化倍数为3.32.

  20. Cloning and expression analysis about fruit coloring related Phenylalanine Ammonia-lyase gene fragment from Pingguoli%苹果梨果实着色相关PAL基因片段克隆及表达分析

    Institute of Scientific and Technical Information of China (English)

    孙百灵; 王旭; 曲柏宏

    2012-01-01

    Make the Pingguoli peel as the material,coloring related PAL(fragment) was cloned,accession number:JN120855.The results showed that the fragment includes 407 basepair,the consistency between fragment and Yali pear PAL gene is 97%,and the amino acid sequence homology is the highest,restriction analysis showed that there was a commonly used restriction enzyme site for AccI.The semi-quantitative RT-PCR technique showed that as fruit mature,expression of PAL gene is increasing constantly about bagged fruit and no bagged fruit,but expression of the bagged fruit is obviously higher than no bagged fruit in the fruit mature.%以苹果梨果皮为试材,克隆了苹果梨果实着色相关PAL基因片段,GenBank登录号为JN120855。结果表明:该基因片段长度为407bp,与鸭梨PAL基因序列一致性达97%,与鸭梨氨基酸序列同源性最高,酶切位点分析表明,该PAL基因序列含有常用的限制性内切酶AccI的识别位点。半定量RT-PCR分析表明,随着果实的成熟,套袋果与未套袋果PAL基因的表达量都不断增加,但套袋果在果实成熟期的表达量明显高于未套袋果。

  1. GenBank blastx search result: AK240729 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240729 J043030H19 AJ421809.1 PFL421809 Pseudomonas fluorescens hutH-2 gene (partial) for putat ... ive histidine ... ammonia lyase, hutH-1 gene for putative histidine ... ammonia lyase and hutT gene (partial) for putative histidine ... transport protein. BCT 2e-27 1 ...

  2. GenBank blastx search result: AK061959 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK061959 001-042-G01 AJ421809.1 Pseudomonas fluorescens hutH-2 gene (partial) for putative histidine ... dine ammonia lyase, hutH-1 gene for putative histidine ... ammonia lyase and hutT gene (partial) for putative ... histidine ... transport protein.|BCT BCT 2e-17 +1 ...

  3. Strains for the production of flavonoids from glucose

    Energy Technology Data Exchange (ETDEWEB)

    Stephanopoulos, Gregory; Santos, Christine; Koffas, Mattheos

    2015-11-13

    The invention relates to the production of flavonoids and flavonoid precursors in cells through recombinant expression of tyrosine ammonia lyase (TAL), 4-coumarate:CoA ligase (4CL), chalcone synthase (CHS), and chalcone isomerase (CHI).

  4. Phenolic compounds and related enzymes as determinants of sorghum for food use

    NARCIS (Netherlands)

    Dicko, M.H.; Gruppen, H.; Traore, A.S.; Voragen, A.G.J.; Berkel, van W.J.H.

    2006-01-01

    Phenolic compounds and related enzymes such as phenol biosynthesizing enzymes (phenylalanine ammonia lyase) and phenol catabolizing enzymes (polyphenol oxidase and peroxidase) are determinants for sorghum utilization as human food because they influence product properties during and after sorghum pr

  5. AcEST: DK957009 [AcEST

    Lifescience Database Archive (English)

    Full Text Available 0. 5' end sequence. DK957009 CL1105Contig1 Show DK957009 Clone id TST39A01NGRL0027_D20 Library TST39 Length 552 Definition Adian...Q9SS45|PAL4_ARATH Phenylalanine ammonia-lyase 4 OS=Arabidopsi... 77 7e-14 sp|P25872|PAL1_TOBAC Phenylalanine ammonia...a-lyase 2 OS=Arabidopsi... 74 4e-13 sp|P45733|PAL3_TOBAC Phenylalanine ammonia-lyase OS=Nicotian...-lyase 3 OS=Arabidopsi... 73 8e-13 sp|P35513|PAL2_TOBAC Phenylalanine ammonia-lyase OS=Nicotian... sp|P52777|PALY_PINTA Phenylalanine ammonia-lyase OS=Pinus taeda Align length 91 Scor

  6. Main: AGMOTIFNTMYB2 [PLACE

    Lifescience Database Archive (English)

    Full Text Available AGMOTIFNTMYB2 S000444 28-Jan-2004 (last modified) kehi AG-motif found at -114 of th... gene phenylalanine ammonia lyase (PAL), which are induced by various stress such as wounding or elicitor treatm

  7. Effects of germination on the activities of amylases and phenolic enzymes in sorghum varieties grouped according to food end-use properties

    NARCIS (Netherlands)

    Dicko, M.H.; Gruppen, H.; Zouzouho, O.C.; Traore, A.S.; Berkel, van W.J.H.; Voragen, A.G.J.

    2006-01-01

    Fifty sorghum varieties were screened to determine the effects of germination on levels of starch, -amylase, -amylase, phenylalanine ammonia lyase (PAL), peroxidase (POX) and polyphenol oxidase (PPO). Germination decreased starch content, with amylose being more degraded than amylopectin. In germina

  8. Differential accumulation of plant defense gene transcripts in a compatible and an incompatible plant-pathogen interaction.

    OpenAIRE

    Bell, J N; Ryder, T B; Wingate, V P; Bailey, J.A.; Lamb, C. J.

    1986-01-01

    Phenylalanine ammonia-lyase and chalcone synthase catalyze the first reaction of phenylpropanoid biosynthesis and the first reaction of a branch pathway specific for flavonoid-isoflavonoid biosynthesis, respectively. These enzymes are key control elements in the synthesis of kievitone, phaseollin, and related isoflavonoid-derived phytoalexins. RNA blot hybridization with 32P-labeled cDNA sequences was used to demonstrate marked accumulation of phenylalanine ammonia-lyase and chalcone synthase...

  9. AcEST: BP913928 [AcEST

    Lifescience Database Archive (English)

    Full Text Available Swiss-Prot sp_hit_id O64963 Definition sp|O64963|PAL1_PRUAV Phenylalanine ammonia... to BlastX Result : TrEMBL tr_hit_id Q5EP58 Definition tr|Q5EP58|Q5EP58_PTEAQ Phenylalanine ammonia lyase (F...13928 - Show BP913928 Clone id YMU001_000037_H09 Library YMU01 Length 492 Definition Adiantum capillus-veneris mRNA. clon...-lyase OS=Nicotiana ta... 134 3e-31 sp|P27991|PAL1_SOYBN Phenylalanine ammonia...-lyase 1 OS=Petroselin... 127 3e-29 sp|P35513|PAL2_TOBAC Phenylalanine ammonia-lyase OS=Nicotian

  10. Metabolically engineered cells for the production of resveratrol or an oligomeric or glycosidically-bound derivative thereof

    DEFF Research Database (Denmark)

    2006-01-01

    A recombinant micro-organism producing resveratrol by a pathway in which phenylalanine ammonia lyase (PAL) produces trans-cinnamic acid from phenylalanine, cinnamate 4- hydroxylase (C4H) produces 4-coumaric acid from said trans- cinnamic acid, 4-coumarate-CoA ligase (4CL) produces 4- coumaroyl Co...

  11. Main: TATABOXOSPAL [PLACE

    Lifescience Database Archive (English)

    Full Text Available TATABOXOSPAL S000400 27-Aug-2002 (last modified) uchi Binding site for OsTBP2, found in the prom ... henylalanine ammonia-lyase; OsTFIIB stimulated the DNA ... binding and bending activities of OsTBP2 and syner ... nscription from the pal promoter; TBP; TFIIB; pal; DNA ... binding and bending; Oryza sativa (rice) TATTTAA ...

  12. Ultraviolet-B light treatment increases antioxidant capacity of carrot products

    Science.gov (United States)

    Abiotic stresses such as cutting and ultraviolet (UV) light exposure of plant cells triggers an increased activity response by phenylalanine ammonia-lyase (PAL) and chalcone synthase resulting in increased synthesis of phenolic compounds, mainly anthocyanins and flavonoids. This study investigated ...

  13. Effect of UV-B light and different cutting styles on antioxidant enhancement of commercial fresh-cut carrot products

    Science.gov (United States)

    Carrots are a rich source of antioxidants. Fresh-cut processing provides a convenient way to consume this nutritious root crop. Cutting operations induce wounding stress activation of phenylalanine ammonia-lyase (PAL) and chalcone synthase, and enhance the nutrient content of carrots by increasing t...

  14. Antioxidant characterization and sensory evaluation during storage of ultraviolet-B light exposed baby carrots (abstract)

    Science.gov (United States)

    Baby carrot processing induces wounding stress activation of phenylalanine ammonia-lyase (PAL), enhancing its nutrient content by increasing synthesis of secondary metabolites. Ultraviolet-B (UV-B) exposure further promotes the formation of soluble phenolic compounds, significantly increasing antiox...

  15. Expression and mapping of anthocyanin biosynthesis genes in carrot

    Science.gov (United States)

    Anthocyanin gene expression has been extensively studied in leaves, fruits and flowers of numerous plants. Little, however, is known about anthocyanin accumulation in roots, or in carrots or other Apiaceae. We quantified expression of six anthocyanin biosynthetic genes (phenylalanine ammonia-lyase (...

  16. Main: PALBOXAPC [PLACE

    Lifescience Database Archive (English)

    Full Text Available PALBOXAPC S000137 06-January-2006 (last modified) kehi Box A; Consensus; One of three putative c ... P, A, and L) of phenylalanine ammonia-lyase (PAL; EC ... 4.3.1.5) genes in parsley (P.c.); None of these el ... light responsiveness. These elements appear to be nec essary but not sufficient for elicitor- or light-me ...

  17. New Strategies for the Treatment of Phenylketonuria (PKU

    Directory of Open Access Journals (Sweden)

    Pietro Strisciuglio

    2014-11-01

    Full Text Available Phenylketonuria (PKU was the first inherited metabolic disease in which dietary treatment was found to prevent the disease’s clinical features. Treatment of phenylketonuria remains difficult due to progressive decrease in adherence to diet and the presence of neurocognitive defects despite therapy. This review aims to summarize the current literature on new treatment strategies. Additions to treatment include new, more palatable foods based on glycomacropeptide that contains very limited amount of aromatic amino acids, the administration of large neutral amino acids to prevent phenylalanine entry into the brain or tetrahydropterina cofactor capable of increasing residual activity of phenylalanine hydroxylase. Moreover, human trials have recently been performed with subcutaneous administration of phenylalanine ammonia-lyase, and further efforts are underway to develop an oral therapy containing phenylanine ammonia-lyase. Gene therapy also seems to be a promising approach in the near future.

  18. New Strategies for the Treatment of Phenylketonuria (PKU).

    Science.gov (United States)

    Strisciuglio, Pietro; Concolino, Daniela

    2014-01-01

    Phenylketonuria (PKU) was the first inherited metabolic disease in which dietary treatment was found to prevent the disease's clinical features. Treatment of phenylketonuria remains difficult due to progressive decrease in adherence to diet and the presence of neurocognitive defects despite therapy. This review aims to summarize the current literature on new treatment strategies. Additions to treatment include new, more palatable foods based on glycomacropeptide that contains very limited amount of aromatic amino acids, the administration of large neutral amino acids to prevent phenylalanine entry into the brain or tetrahydropterina cofactor capable of increasing residual activity of phenylalanine hydroxylase. Moreover, human trials have recently been performed with subcutaneous administration of phenylalanine ammonia-lyase, and further efforts are underway to develop an oral therapy containing phenylanine ammonia-lyase. Gene therapy also seems to be a promising approach in the near future. PMID:25375236

  19. Physiological and biochemical characteristics of tobacco transgenic plants expressing bacterial dioxygenase

    Czech Academy of Sciences Publication Activity Database

    Piruzian, S.; Goldenkova, V.; Lenets, A.; Cvikrová, Milena; Macháčková, Ivana; Kobets, N.; Mett, V.

    2002-01-01

    Roč. 49, č. 6 (2002), s. 817-822. ISSN 1021-4437 R&D Projects: GA MŠk LN00A081; GA ČR GA206/00/1354 Institutional research plan: CEZ:AV0Z5038910 Keywords : phenylalanine ammonia lyase * polyphenol oxidases * biosynthesis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.102, year: 2002

  20. Defense Responses in Rice Induced by Silicon Amendment against Infestation by the Leaf Folder Cnaphalocrocis medinalis

    OpenAIRE

    Han, Yongqiang; Li, Pei; Gong, Shaolong; YANG Lang; Wen, Lizhang; Hou, Maolin

    2016-01-01

    Silicon (Si) amendment to plants can confer enhanced resistance to herbivores. In the present study, the physiological and cytological mechanisms underlying the enhanced resistance of plants with Si addition were investigated for one of the most destructive rice pests in Asian countries, the rice leaf folder, Cnaphalocrocis medinalis (Guenée). Activities of defense-related enzymes, superoxide dismutase, peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase, and concentrati...

  1. Gene-enzyme relationships in somatic cells and their organismal derivatives in higher plants. Progress report

    International Nuclear Information System (INIS)

    Several enzymes involved in the biosynthesis of aromatic amino acids have been isolated from Nicotiana silvestris. Isozymes of chlorismate mutase were isolated, partially purified and subjected to enzyme kinetic analysis. In addition, studies investigating the role of 5-enolpyruvyl-shikimate-3-phosphate synthetase, 3-deoxy-D-arabino-heptulosonate 7-phosphate synthetase, shikimate dehydrogenase, prephenate aminotransferase, arogenate dehydrogenase and phenylalanine ammonia-lyase in regulation of aromatic amino acids levels in tobacco are reported

  2. Identification of the Substrate Radical Intermediate Derived from Ethanolamine During Catalysis by Ethanolamine Ammonia-Lyase†

    OpenAIRE

    Bender, Güneş; Poyner, Russell R.; Reed, George H.

    2008-01-01

    Rapid-mix freeze-quench (RMFQ) methods and electron paramagnetic resonance (EPR) spectroscopy have been used to characterize the steady-state radical in the deamination of ethanolamine catalyzed by adenosylcobalamin (AdoCbl)-dependent ethanolamine ammonia-lyase (EAL). EPR spectra of the radical intermediates formed with the substrates, [1-13C]ethanolamine, [2-13C]ethanolamine, and unlabeled ethanolamine were acquired using RMFQ trapping methods from 10 ms to completion of the reaction. Resolv...

  3. Ethanolamine utilization in Vibrio alginolyticus

    OpenAIRE

    Khatri Neelam; Khatri Indu; Subramanian Srikrishna; Raychaudhuri Saumya

    2012-01-01

    Abstract Ethanolamine is used as an energy source by phylogenetically diverse bacteria including pathogens, by the concerted action of proteins from the eut-operon. Previous studies have revealed the presence of eutBC genes encoding ethanolamine-ammonia lyase, a key enzyme that breaks ethanolamine into acetaldehyde and ammonia, in about 100 bacterial genomes including members of gamma-proteobacteria. However, ethanolamine utilization has not been reported for any member of the Vibrio genus. O...

  4. Functions required for vitamin B12-dependent ethanolamine utilization in Salmonella typhimurium.

    OpenAIRE

    Roof, D M; Roth, J R

    1989-01-01

    When B12 is available, Salmonella typhimurium can degrade ethanolamine to provide a source of carbon and nitrogen. B12 is essential since it is a cofactor for ethanolamine ammonia-lyase, the first enzyme in ethanolamine breakdown. S. typhimurium makes B12 only under anaerobic conditions; in the presence of oxygen, exogenous B12 must be provided to permit ethanolamine utilization. Genes required for ethanolamine utilization are encoded in the eut operon. For complementation testing, an F' plas...

  5. Comparative Genomics of Ethanolamine Utilization▿ † ‡

    OpenAIRE

    Tsoy, Olga; Ravcheev, Dmitry; Mushegian, Arcady

    2009-01-01

    Ethanolamine can be used as a source of carbon and nitrogen by phylogenetically diverse bacteria. Ethanolamine-ammonia lyase, the enzyme that breaks ethanolamine into acetaldehyde and ammonia, is encoded by the gene tandem eutBC. Despite extensive studies of ethanolamine utilization in Salmonella enterica serovar Typhimurium, much remains to be learned about EutBC structure and catalytic mechanism, about the evolutionary origin of ethanolamine utilization, and about regulatory links between t...

  6. Isolation and genetic characterizations of Bacillus megaterium cobalamin biosynthesis-deficient mutants.

    OpenAIRE

    Wolf, J B; Brey, R N

    1986-01-01

    Ethanolamine is deaminated by the action of ethanolamine ammonia-lyase (EC 4.3.1.7), an adenosylcobalamin-dependent enzyme. Consequently, to grow on ethanolamine as a sole nitrogen source, Bacillus megaterium requires vitamin B12. Identification of B. megaterium mutants deficient for growth on ethanolamine as the sole nitrogen source yielded a total of 34 vitamin B12 auxotrophs. The vitamin B12 auxotrophs were divided into two major phenotypic groups: Cob mutants, which could use cobinamide o...

  7. Comparative genomics of ethanolamine utilization

    OpenAIRE

    Tsoy, Olga; Ravcheev, Dmitry; Mushegian, Arcady

    2009-01-01

    Ethanolamine can be used as a source of carbon and nitrogen by phylogenetically diverse bacteria. Ethanolamine-ammonia lyase, the enzyme that breaks ethanolamine into acetaldehyde and ammonia, is encoded by the gene tandem eutBC. Despite extensive studies of ethanolamine utilization in Salmonella enterica serovar Typhimurium, much remains to be learned about EutBC structure and catalytic mechanism, about the evolutionary origin of ethanolamine utilization, and about regulatory links between t...

  8. Bacillus cereus AR156-Induced Resistance to Colletotrichum acutatum Is Associated with Priming of Defense Responses in Loquat Fruit

    OpenAIRE

    Wang, Xiaoli; Wang, Lei; Wang, Jing; Jin, Peng; Liu, Hongxia; Zheng, Yonghua

    2014-01-01

    The effectiveness of a biocontrol agent Bacillus cereus AR156 for control of anthracnose rot caused by Colletotrichum acutatum in harvested loquat fruit and the possible mechanisms of its action have been investigated. Treatment of fruit with B. cereus AR156 resulted in lower disease incidence and smaller lesion diameters compared with that of untreated fruit. The treatment enhanced activities of defense-related enzymes including chitinase, β-1, 3-glucanase, phenylalanine ammonia-lyase, perox...

  9. Growth and physiological changes in continuously cropped eggplant (Solanum melongena L.) upon relay intercropping with garlic (Allium sativum L.)

    OpenAIRE

    Wang, Mengyi; Wu, Cuinan; Cheng, Zhihui; Meng, Huanwen

    2015-01-01

    Relay intercropping represents an alternative for sustainable production of vegetables, but the changes of internally antioxidant defense combined with the growth and yield are not clear. Field experiment was carried out to investigate the malondialdehyde (MDA) content and activity levels of superoxide dismutase (SOD), peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) in eggplant (Solanum melongena L.) and plant height, stem diameter, maximal leaf area, and yie...

  10. Expression quantitative trait loci infer the regulation of isoflavone accumulation in soybean (Glycine max L. Merr.) seed

    OpenAIRE

    Wang, Yan; Han, Yingpeng; Teng, Weili; Zhao, Xue; Li, Yongguang; Wu, Lin; Li, Dongmei; Li, Wenbin

    2014-01-01

    Background Mapping expression quantitative trait loci (eQTL) of targeted genes represents a powerful and widely adopted approach to identify putative regulatory variants. Linking regulation differences to specific genes might assist in the identification of networks and interactions. The objective of this study is to identify eQTL underlying expression of four gene families encoding isoflavone synthetic enzymes involved in the phenylpropanoid pathway, which are phenylalanine ammonia-lyase (PA...

  11. Primary, Secondary Metabolites, Photosynthetic Capacity and Antioxidant Activity of the Malaysian Herb Kacip Fatimah (Labisia Pumila Benth) Exposed to Potassium Fertilization under Greenhouse Conditions

    OpenAIRE

    Ali Ghasemzadeh; Jaafar, Hawa Z. E.; Ehsan Karimi; Mohd Hafiz Ibrahim

    2012-01-01

    A randomized complete block design was used to characterize the relationship between production of total phenolics, flavonoids, ascorbic acid, carbohydrate content, leaf gas exchange, phenylalanine ammonia-lyase (PAL), soluble protein, invertase and antioxidant enzyme activities (ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD) in Labisia pumila Benth var. alata under four levels of potassium fertilization experiments (0, 90, 180 and 270 kg K/ha) conducted for 12 week...

  12. Co-ordinated synthesis of phytoalexin biosynthetic enzymes in biologically-stressed cells of bean (Phaseolus vulgaris L.)

    OpenAIRE

    Cramer, Carole L; Bell, John N.; Ryder, Thomas B.; Bailey, John A.; Schuch, Wolfgang; Bolwell, G. Paul; Robbins, Mark P.; Dixon, Richard A.; Lamb, Chris J.

    1985-01-01

    Changes in the rates of synthesis of three enzymes of phenyl-propanoid biosynthesis in Phaseolus vulgaris L. (dwarf French bean) have been investigated by immunoprecipitation of [35S]methionine-labeled enzyme subunits with mono-specific antisera. Elicitor causes marked, rapid but transient co-ordinated increases in the rate of synthesis of phenyl-alanine ammonia-lyase, chalcone synthase and chalcone isomerase concomitant with the phase of rapid increase in enzyme activity at the onset of accu...

  13. Modular Optimization of Heterologous Pathways for De Novo Synthesis of (2S)-Naringenin in Escherichia coli

    OpenAIRE

    Junjun Wu; Tiantian Zhou; Guocheng Du; Jingwen Zhou; Jian Chen

    2014-01-01

    Due to increasing concerns about food safety and environmental issues, bio-based production of flavonoids from safe, inexpensive, and renewable substrates is increasingly attracting attention. Here, the complete biosynthetic pathway, consisting of 3-deoxy-D-arabinoheptulosonate 7-phosphate synthase (DAHPS), chorismate mutase/prephenate dehydrogenase (CM/PDH), tyrosine ammonia lyase (TAL), 4-coumarate:CoA ligase (4CL), chalcone synthase (CHS), chalcone isomerase (CHI), malonate synthetase, and...

  14. EVALUATION OF PAL ACTIVITY, PHENOLIC AND FLAVONOID CONTENTS IN THREE PISTACHIO ( PISTACIA VERA L.) CULTIVARS GRAFTED ONTO THREE DIFFERENT ROOTSTOCKS

    OpenAIRE

    N. Nadernejad; Ahmadimoghadam, A.; J. Hossyinifard; S. Poorseyedi

    2013-01-01

    Phenylalanine ammonia lyase (PAL) is a biochemical marker of the environmental stress and plays a pivotal role in phenolic synthesis. The lower ROS level and oxidative damage was observed in grafted plants and the rootstocks have a profound influence on the biochemical composition, especially phenolic compounds. Regarding the importance of the effect rootstocks have on scion in pistachio trees, this study was carried out to assess and compare three pistachio cultivars ("Ahmadaghaii", "Ohadi" ...

  15. Main: PALBOXPPC [PLACE

    Lifescience Database Archive (English)

    Full Text Available n parsley (P.c.); None of these elements (boxes P, A, and L) alone, or the promoter region containing all of... them together, conferred elicitor or light responsiveness. These elements appear...ee putative cis-acting elements (boxes P, A, and L) of phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) genes i...PALBOXPPC S000136 06-January-2006 (last modified) kehi Box P; Consensus; One of thr

  16. Main: PALBOXLPC [PLACE

    Lifescience Database Archive (English)

    Full Text Available n parsley (P.c.); None of these elements (boxes P, A, and L) alone, or the promoter region containing all of... them together, conferred elicitor or light responsiveness. These elements appear...ee putative cis-acting elements (boxes P, A, and L) of phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) genes i...PALBOXLPC S000138 06-January-2006 (last modified) kehi Box L; Consensus; One of thr

  17. Effect of metabolic regulators on aluminium uptake and toxicity in Matricaria chamomilla plants

    Czech Academy of Sciences Publication Activity Database

    Kováčik, J.; Štork, F.; Klejdus, B.; Grúz, Jiří; Hedbavny, J.

    2012-01-01

    Roč. 54, May 2012 (2012), s. 140-148. ISSN 0981-9428 R&D Projects: GA AV ČR KAN200380801 Grant ostatní: GA ČR(CZ) GA525/07/0338; GA MŠk(CZ) ED1.1.00/02.0068 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cinnamic acid * Mineral nutrients * Phenylalanine ammonia-lyase Subject RIV: ED - Physiology Impact factor: 2.775, year: 2012

  18. Early Phenylpropanoid Biosynthetic Steps in Cannabis sativa: Link between Genes and Metabolites

    OpenAIRE

    Immacolata Coraggio; Monica Mattana; Roberto Consonni; Teresa Docimo

    2013-01-01

    Phenylalanine ammonia-lyase (PAL), Cinnamic acid 4-hydroxylase (C4H) and 4-Coumarate: CoA ligase (4CL) catalyze the first three steps of the general phenylpropanoid pathway whereas chalcone synthase (CHS) catalyzes the first specific step towards flavonoids production. This class of specialized metabolites has a wide range of biological functions in plant development and defence and a broad spectrum of therapeutic activities for human health. In this study, we report the isolation of hemp PAL...

  19. Phenolic compounds and related enzymes as determinants of sorghum for food use

    OpenAIRE

    Dicko, M.H.; Gruppen, H.; Traore, A S; Voragen, A.G.J.; Berkel, van, A.M.

    2006-01-01

    Phenolic compounds and related enzymes such as phenol biosynthesizing enzymes (phenylalanine ammonia lyase) and phenol catabolizing enzymes (polyphenol oxidase and peroxidase) are determinants for sorghum utilization as human food because they influence product properties during and after sorghum processing. Phenolic compounds are quality-grade markers for the preparation of several foods because of enzyme inhibitory activities, color, or antioxidant activities. Large inter-varietal differenc...

  20. Lignification response for rolled leaves of Ctenanthe setosa under long-term drought stress

    OpenAIRE

    TERZİ, Rabiye; GÜLER, Neslihan SARUHAN; ÇALIŞKAN, Nihal KUTLU; KADIOĞLU, Asım

    2013-01-01

    Leaf rolling is a dehydration avoidance mechanism for plants under drought stress. To understand how it affects the lignification process in response to long-term drought stress in Ctenanthe setosa plants that have the leaf-rolling mechanism, the enzymes in lignification were studied in unrolled leaves as a control and at 2 different leaf rolling indices at days 35 and 47 of the drought period. The results indicated that the activities of phenylalanine ammonia lyase, indole-3-acetic acid oxid...

  1. Protective mechanism in UV-B treated Crotalaria juncea L. seedlings

    International Nuclear Information System (INIS)

    The role of antioxidant enzyme activities in Crotalaria juncea under control without UV-B treatment and ultraviolet-B supplemental radiation (UV-B) was investigated. UV-B treatment for 6 h for 4 days resulted in severe inhibition of catalase activity. On the other hand, the activities of peroxidase, polyphenol oxidase, superoxide dismutase and phenylalanine ammonia lyase increased after the UV-B treatment. These increases could be an adaptive mechanism to minimise the effects of UV-B radiation

  2. The Structure of L-Tyrosine 2,3-Aminomutase frmo the C-1027 Enediyne Antitumor Antibiotic Biosynthetic Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Christianson,C.; Montavon, T.; Van Lanen, S.; Shen, B.; Bruner, S.

    2007-01-01

    The SgcC4 L-tyrosine 2,3-aminomutase (SgTAM) catalyzes the formation of (S)-{beta}-tyrosine in the biosynthetic pathway of the enediyne antitumor antibiotic C-1027. SgTAM is homologous to the histidine ammonia lyase family of enzymes whose activity is dependent on the methylideneimidazole-5-one (MIO) cofactor. Unlike the lyase enzymes, SgTAM catalyzes additional chemical transformations resulting in an overall stereospecific 1,2-amino shift in the substrate L-tyrosine to generate (S)-{beta}-tyrosine. Previously, we provided kinetic, spectroscopic, and mutagenesis data supporting the presence of MIO in the active site of SgTAM [Christenson, S. D.; Wu, W.; Spies, A.; Shen, B.; and Toney, M. D. (2003) Biochemistry 42, 12708-12718]. Here we report the first X-ray crystal structure of an MIO-containing aminomutase, SgTAM, and confirm the structural homology of SgTAM to ammonia lyases. Comparison of the structure of SgTAM to the L-tyrosine ammonia lyase from Rhodobacter sphaeroides provides insight into the structural basis for aminomutase activity. The results show that SgTAM has a closed active site well suited to retain ammonia and minimize the formation of lyase elimination products. The amino acid determinants for substrate recognition and catalysis can be predicted from the structure, setting the framework for detailed mechanistic investigations.

  3. The structure of L-tyrosine 2,3-aminomutase from the C-1027 enediyne antitumor antibiotic biosynthetic pathway.

    Science.gov (United States)

    Christianson, Carl V; Montavon, Timothy J; Van Lanen, Steven G; Shen, Ben; Bruner, Steven D

    2007-06-19

    The SgcC4 l-tyrosine 2,3-aminomutase (SgTAM) catalyzes the formation of (S)-beta-tyrosine in the biosynthetic pathway of the enediyne antitumor antibiotic C-1027. SgTAM is homologous to the histidine ammonia lyase family of enzymes whose activity is dependent on the methylideneimidazole-5-one (MIO) cofactor. Unlike the lyase enzymes, SgTAM catalyzes additional chemical transformations resulting in an overall stereospecific 1,2-amino shift in the substrate l-tyrosine to generate (S)-beta-tyrosine. Previously, we provided kinetic, spectroscopic, and mutagenesis data supporting the presence of MIO in the active site of SgTAM [Christenson, S. D.; Wu, W.; Spies, A.; Shen, B.; and Toney, M. D. (2003) Biochemistry 42, 12708-12718]. Here we report the first X-ray crystal structure of an MIO-containing aminomutase, SgTAM, and confirm the structural homology of SgTAM to ammonia lyases. Comparison of the structure of SgTAM to the l-tyrosine ammonia lyase from Rhodobacter sphaeroides provides insight into the structural basis for aminomutase activity. The results show that SgTAM has a closed active site well suited to retain ammonia and minimize the formation of lyase elimination products. The amino acid determinants for substrate recognition and catalysis can be predicted from the structure, setting the framework for detailed mechanistic investigations. PMID:17516659

  4. Metabolically engineered cells for the production of pinosylvin

    DEFF Research Database (Denmark)

    2008-01-01

    A genetically engineered micro-organism having an operative metabolic pathway producing cinnamoyl-CoA and producing pinosylvin therefrom by the action of a stilbene synthase is used for pinosylvin production. Said cinnamic acid may be formed from L-phenylalanine by a L-phenylalanine ammonia lyase...... (PAL) which is one accepting phenylalanine as a substrate and producing cinammic acid therefrom, preferably such that if the PAL also accepts tyrosine as a substrate and forms coumaric acid therefrom, the ratio Km(phenylalanine)/Km(tyrosine) for said PAL is less than 1:1 and if said micro-organism...

  5. Evidence that a B12-Adenosyl Transferase Is Encoded within the Ethanolamine Operon of Salmonella enterica

    OpenAIRE

    Sheppard, David E.; Penrod, Joseph T.; Bobik, Thomas; Kofoid, Eric; Roth, John R.

    2004-01-01

    Adenosylcobalamin (Ado-B12) is both the cofactor and inducer of ethanolamine ammonia lyase (EA-lyase), a catabolic enzyme for ethanolamine. De novo synthesis of Ado-B12 by Salmonella enterica occurs only under anaerobic conditions. Therefore, aerobic growth on ethanolamine requires import of Ado-B12 or a precursor (CN-B12 or OH-B12) that can be adenosylated internally. Several known enzymes adenosylate corrinoids. The CobA enzyme transfers adenosine from ATP to a biosynthetic intermediate in ...

  6. Activities of defense related enzymes induced by benzothiadiazole in rice to blast fungus

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Pretreatment of rice seedlings by foliar spraying with benzothiadiazole (BTH) could induce systematic acquired resistance (SAR) against blast (Magnaporthe grisea) and bacterial leaf blight (Xanthomonas oryzae pv. oryzae) diseases. To elucidate the physiological and biochemical mechanisms of the SAR induced by BTH, we analyzed the changes in activities of phenylalanine ammonia lyase (PAL), cinnamylalcohol dehydrogenase (CAD), peroxidase(POD), lipoxygenase(LOX),β 1,3 glucanase,and chitinase in rice seedlings of susceptible variety pretreated with BTH and challenged by M. grisea.

  7. Biosynthesis of phenolic compounds in hypocotyl callus cultures of fenugreek (Trigonella foenum graceum L.)

    International Nuclear Information System (INIS)

    Chromatographic analysis of ethanolic extracts of hypocotyl callus cultures of fenugreck during various stages of growth has revealed that various phenolic acids including intermediates in the biosynthesis of lignin and flavonoid are synthesised in the callous cultures. Label fro, both phenylamine-U-14C and cinnamic acid--U-14C incorporates into these phenolic acids. Phenylalanine ammonia lyase (Ec.4.3.1.5) has been demonstrated in these cultures and certain aspects of its regulation are studied. (M.G.B.)

  8. Induction of anthocyanin formation and of enzymes related to its biosynthesis by UV light in cell cultures of Haplopappus gracilis

    International Nuclear Information System (INIS)

    Only UV light below 345 nm stimulates anthocyanin formation in dark grown cell suspension cultures of Haplopappus gracilis. A linear relationship between UV dose and flavonoid accumulation, as found previously with parsley cell cultures was not observed with the H.gracilis cells. Only continuous irradiation with high doses of UV was effective. Drastic increases in the activities of the enzymes phenylalanine ammonia-lyase, chalcone isomerase and flavanone synthase were observed under continuous UV light. The increase in enzyme activities paralleled anthocyanin formation. (author)

  9. Allocation of Secondary Metabolites, Photosynthetic Capacity, and Antioxidant Activity of Kacip Fatimah (Labisia pumila Benth) in Response to CO2 and Light Intensity

    OpenAIRE

    Mohd Hafiz Ibrahim; Jaafar, Hawa Z. E.; Ehsan Karimi; Ali Ghasemzadeh

    2014-01-01

    A split plot 3 by 4 experiment was designed to investigate and distinguish the relationships among production of secondary metabolites, soluble sugar, phenylalanine ammonia lyase (PAL; EC 4.3.1.5) activity, leaf gas exchange, chlorophyll content, antioxidant activity (DPPH), and lipid peroxidation under three levels of CO2 (400, 800, and 1200  μ mol/mol) and four levels of light intensity (225, 500, 625, and 900  μ mol/m2/s) over 15 weeks in Labisia pumila. The production of plant secondary m...

  10. Physiology and Biochemistry Changes of Euphorbia pulcherrima During Leaf Color Transformation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Reasons for the color change of E.pulcherrima were studied with physiological and biochemical paraments such as: chlorophyll,carotenoids,anthocyanin,Phenylalanine ammonia-lyase (PAL),pH of cell sap in leaves and soluble sugar content etc.The results showed that during the period of the leaf color transmittion of E.pulcherrima,the contents of plastid pigment,soluble sugar and pH of cells sap in leaves showed a high-low-high dynamic change,while the contents of anthocyanin and PAL activity showed the low-high...

  11. 4-methylideneimidazole-5-one-containing aminomutases in enediyne biosynthesis.

    Science.gov (United States)

    Lohman, Jeremy R; Shen, Ben

    2012-01-01

    Many natural products contain unusual aromatic β-amino acids or moieties derived therefrom. The biosynthesis of these β-amino acids was first elucidated during a biosynthetic study of the enediyne antitumor antibiotic C-1027, when an enzyme, SgcC4, was discovered to convert L-tyrosine to (S)-β-tyrosine. SgcC4 is similar in sequence and structure to 4-methylideneimidazole-5-one (MIO)-containing ammonia lyases. Whereas the ammonia lyases use the electrophilic power of the MIO group to catalyze the release of ammonia from aromatic amino acids to generate α,β-unsaturated carboxylic acids as final products, SgcC4 retains the α,β-unsaturated carboxylic acid and amine as intermediates and reappends the amino group to the β-carbon, affording a β-amino acid as the final product. The study of SgcC4 led to the subsequent discovery of other MIO-containing aminomutases with altered substrate specificity and product stereochemistry, including MdpC4 from the biosynthetic pathway of the enediyne antitumor antibiotic maduropeptin. This chapter describes protocols for the enzymatic and structural characterization of these MIO-containing aminomutases as exemplified by SgcC4 and MdpC4. These protocols are applicable to the study of other aminomutases. PMID:23034235

  12. UV-induced peroxidase and phenylalanine ammonialyase activity and phaseollin accumulation in leaves of Phaseolus Vulgaris in relation to ethylene

    International Nuclear Information System (INIS)

    Attached or detached leaves of bean (Phaseolus vulgaris L.) were irradiated with short-wave UV light (254 nm) which resulted in increased ethylene production, increased activity of soluble and ionically bound peroxidase, increased activity of phenylalanine ammonia-lyase and an accumulation of phaseollin, accompanied by bronzing of these leaves. In order to evaluate the role of ethylene in this process, plants were pretreated with 0.5 mM aminoethoxyvinylglycine (AVG), an inhibitor of ethylene biosynthesis, or with 0.45 mM 5-methyl-7-chloro-4-ethoxycarboxylmethoxy-2,1,3-benzothiodiazole (DU), a presumed inhibitor of ethylene action. Both compounds showed an inhibitory effect on UV-induced ethylene production. DU stimulated UV-induced peroxidase activity, whereas AVG seemed to decrease UV-induced peroxidase activity. DU and AVG had only a weak inhibitory effect on UV-induced PAL activity. Both compounds retarded slightly the accumulation of phaseollin and the appearance of necrotic symptoms in UV-irradiated bean leaves. Ethephon treatment (500 or 1000 ppm) failed to induce the accumulation of phaseollin in attached or detached leaves of bean. The role of ethylene in UV-induced peroxidase and phenylalanine ammonia-lyase (PAL) activity and accumulation of phaseollin in bean leaves is discussed. (author)

  13. Ozone-induced changes in the content of bioactive compounds and enzyme activity during storage of pepper fruits.

    Science.gov (United States)

    Sachadyn-Król, Monika; Materska, Małgorzata; Chilczuk, Barbara; Karaś, Monika; Jakubczyk, Anna; Perucka, Irena; Jackowska, Izabella

    2016-11-15

    This paper presents for the first time the results of investigations concerning the effect of treatment of whole pepper fruits with gaseous ozone and the refrigeration storage period conditions on pepper quality. The effects are reflected in changes in the flavonoid contents, the antioxidant activity of the phenolic compound fraction and the enzymes involved in phenylpropanoid metabolism. The investigations were carried out on a hot pepper fruit cultivar, Cyklon. It was found that the levels of a majority of flavonoids, in particular those of quercetin 3-O-rhamnoside and quercetin 3-O-rhamnoside-7-O-glucoside increased in the pericarp of fruits treated with ozone for 3h and stored for 20days (by 25% relative to the control). Simultaneously, reduced phenylalanine ammonia-lyase and tyrosine ammonia-lyase activity were noted, which implies slight degradation of enzymes caused by the ozone treatment and enhancement of the polyphenol oxidase and guaiacol oxidase activity involved in response to increased oxidative stress. PMID:27283607

  14. Biochemical changes involved in browning of gamma-irradiated cut witloof chicory

    International Nuclear Information System (INIS)

    The increasing browning phenomenon of cut witloof chicory (Cichorium intybus) irradiated with a dose of 3 kGy and stored five days at 10 °C was investigated in relation to total phenolic concentration, phenylalanine ammonia-lyase activity, total and reduced glutathione content, polyphenol oxidase and peroxidase activities. Phenylalanine ammonia-lyase activity underwent a strong activation with a maximum on the second day of storage, and total phenolic compounds tended to accumulate from the third day. Glutathione content was monitored as indicator of antioxidant capacities. Total glutathione decreased by 25% after irradiation and was restored on the third day of storage, while the 50% decrease of reduced glutathione was maintained along the five days. Conversely, a 30% inhibition of polyphenol oxidase and peroxidase activities occured after irradiation. We concluded first that irradiation-induced browning of cut chicory may be due to both an increase of phenolic metabolism and a reduction in antioxidant capacities, and second that increased membrane permeability may allow substrate-enzyme contact

  15. Zinc Induced Enzymatic Defense Mechanisms in Rhizoctonia Root Rot Infected Clusterbean Seedlings

    Directory of Open Access Journals (Sweden)

    Neha Wadhwa

    2014-01-01

    Full Text Available This investigation was planned to determine the effect of different concentrations of zinc (Zn on biochemical constituents of clusterbean, which play an important role in disease resistance mechanisms. Clusterbean seedlings were grown with 0, 10, or 20 mg Zn kg−1 soil treatments in earthen pots filled with 700 g inoculated soil. Soil was inoculated by pretreatment with 250 mg (wet weight of Rhizoctonia inoculums per pot. A similar set was maintained in uninoculated soil. Root rot incidence decreased to 41 and 27 per cent with 10 and 20 mg Zn kg−1 soil treatments, respectively, as compared to 68 percent at control. Antioxidative enzyme activity (polyphenol oxidase, peroxidase, phenylalanine ammonia lyase, and tyrosine ammonia lyase increased in inoculated seedlings and was increased further by 20 mg Zn kg−1 soil treatment. Antioxidative enzymes play an important role against fungal invasion, as peroxidase is involved in the formation of barrier via lignifications at the site of pathogen penetration. PAL and TAL play a key role in phenylpropanoid metabolism and could perform defense-related functions. Zn acts as a cofactor for these enzymes, so it can be concluded that Zn may be used as a soil-nutritive agent to increase resistance in plants against fungal diseases.

  16. De Novo Synthesis of Benzenoid Compounds by the Yeast Hanseniaspora vineae Increases the Flavor Diversity of Wines.

    Science.gov (United States)

    Martin, Valentina; Giorello, Facundo; Fariña, Laura; Minteguiaga, Manuel; Salzman, Valentina; Boido, Eduardo; Aguilar, Pablo S; Gaggero, Carina; Dellacassa, Eduardo; Mas, Albert; Carrau, Francisco

    2016-06-01

    Benzyl alcohol and other benzenoid-derived metabolites of particular importance in plants confer floral and fruity flavors to wines. Among the volatile aroma components in Vitis vinifera grape varieties, benzyl alcohol is present in its free and glycosylated forms. These compounds are considered to originate from grapes only and not from fermentative processes. We have found increased levels of benzyl alcohol in red Tannat wine compared to that in grape juice, suggesting de novo formation of this metabolite during vinification. In this work, we show that benzyl alcohol, benzaldehyde, p-hydroxybenzaldehyde, and p-hydroxybenzyl alcohol are synthesized de novo in the absence of grape-derived precursors by Hanseniaspora vineae. Levels of benzyl alcohol produced by 11 different H. vineae strains were 20-200 times higher than those measured in fermentations with Saccharomyces cerevisiae strains. These results show that H. vineae contributes to flavor diversity by increasing grape variety aroma concentration in a chemically defined medium. Feeding experiments with phenylalanine, tryptophan, tyrosine, p-aminobenzoic acid, and ammonium in an artificial medium were tested to evaluate the effect of these compounds either as precursors or as potential pathway regulators for the formation of benzenoid-derived aromas. Genomic analysis shows that the phenylalanine ammonia-lyase (PAL) and tyrosine ammonia lyase (TAL) pathways, used by plants to generate benzyl alcohols from aromatic amino acids, are absent in the H. vineae genome. Consequently, alternative pathways derived from chorismate with mandelate as an intermediate are discussed. PMID:27193819

  17. Enhancement of plant growth activity of irradiated chitosan by molecular weight fractionation

    International Nuclear Information System (INIS)

    The chitosan products irradiated at 25-200 kGy in 10% solution showed a positive effect on the growth of barley, while the unirradiated chitosan inhibited the growth of this plant. The 100 kGy irradiated chitosan product with average molecular weight (Mw) approx. 16 kDa was found as optimal to plant growth activity. Separation of the degraded samples was performed using ultrafiltration membranes and was found that the fraction F2 with Mw in range of 1 - 3 kDa not only showed a remarkable effect on the growth of barley and soybean, but also significantly increased the activity of phytoalexin enzymes, namely phenylalanine ammonia lyase (87%) and chitinase (186%). This fraction also increased 15.8% seed yield of soybean after three month cultivation. The results suggested that the irradiated chitosan fraction F2 with Mw in range of 1 - 3 kDa was a trigger for plant growth activity. (author)

  18. Interrelationships between Bacillus sp. CHEP5 and Bradyrhizobium sp. SEMIA6144 in the induced systemic resistance against Sclerotium rolfsii and symbiosis on peanut plants

    Indian Academy of Sciences (India)

    Marí­a Soledad Figueredo; María Laura Tonellie; Tania Taurian; Jorge Angelini; Fernando Ibañez; Lucio Valetti; Vanina Muñoz; Marí­a Soledad Anzuay; Liliana Ludueña; Adriana Fabra

    2014-12-01

    Plant-growth-promoting bacteria are often used to enhance crop yield and for biological control of phytopathogens. Bacillus sp. CHEP5 is a biocontrol agent that induces systemic resistance (ISR) in Arachis hypogaea L. (peanut) against Sclerotium rolfsii, the causal agent of root and stem wilt. In this work, the effect of the co-inoculation of Bacillus sp. CHEP5 and the peanut nodulating strain Bradyrhizobium sp. SEMIA 6144 was studied on induction of both systemic resistance and nodulation processes. Bradyrhizobium sp. SEMIA 6144 did not affect the ability of Bacillus sp. CHEP5 to protect peanut plants from S. rolfsii by ISR and the priming in challenged-plants, as evidenced by an increment in phenylalanine ammonia-lyase enzyme activity. Additionally, the capacity of Bradyrhizobium sp. SEMIA 6144 to induce nodule formation in pathogen-challenged plants was improved by the presence of Bacillus sp. CHEP5.

  19. Effects of Partially N-acetylated Chitosans to Elicit Resistance Reaction on Brassica napus L.

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue-kun; TANG Zhang-lin; CHEN Li; GUO Yi-hong; CHEN Yun-ping; LI Jia-na

    2002-01-01

    The effects to elicit resistance reaction on oilseed rape (Brassica napus L. cv Xinongchangjiao )by four partially N-acetylated chitosan 7B, 8B, 9B and 10B (Degree of acetylation (D. A. ) is 30%, 20%,10%, 0%, respectively) and Glycol chitosan (GC, D.A. is 0%) were investigated and compared. Results showed that chitosan were similar to salicylic acid (SA), and could induce resistance reaction, but the reaction was influenced by the degree of acetylation of chitosan. Fully deacetylated chitosans, 10B and GC, elicited chitinase activity, but partially acetylated chitosan, 7B, 8B and 9B, inhibited chitinase activity. Phenyalanine ammonia-lyase (PAL) was also elicited. Elicitor activity increased with on increasing degree of acetylation, 7B induced highest PAL activity among all chitosans. All chitosans induced peroxidase (POD) in a similar level.After elicited by glycol chitosan, like SA treatment, the seedlings increased disease resistance to Sclerotinia sclerotiorum significantly.

  20. Expression of a flower-specific Myb protein in leaf cells using a viral vector causes ectopic activation of a target promoter.

    Science.gov (United States)

    Sablowski, R W; Baulcombe, D C; Bevan, M

    1995-07-18

    The promoter of the bean PAL2 gene (encoding phenylalanine ammonia-lyase; EC 4.3.1.5) is a model for studies of tissue-restricted gene expression in plants. Petal epidermis is one of the tissues in which this promoter is activated in tobacco. Previous work suggested that a major factor establishing the pattern of PAL2 expression in tobacco petals is the tissue distribution of a protein closely related to Myb305, which is a Myb-like transcriptional activator from snapdragon. In the present work, we show that Myb305 expression in tobacco leaves causes ectopic activation of the PAL2 promoter. To achieve Myb305 expression in planta, a viral expression vector was used. This approach combines the utility of transient assays with the possibility of direct biochemical detection of the introduced factor and may have wider application for studying the function of plant transcription factors. PMID:7624340

  1. Browning inhibition and quality preservation of button mushroom (Agaricus bisporus) by essential oils fumigation treatment.

    Science.gov (United States)

    Gao, Mengsha; Feng, Lifang; Jiang, Tianjia

    2014-04-15

    The effect of essential oil fumigation treatment on browning and postharvest quality of button mushrooms (Agaricus bisporus) was evaluated upon 16 days cold storage. Button mushrooms were fumigated with essential oils, including clove, cinnamaldehyde, and thyme. Changes in the browning index (BI), weight loss, firmness, percentage of open caps, total phenolics, ascorbic acid, microbial activity and activities of polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), and peroxidase (POD) were measured. The results indicated that all essential oils could inhibit the senescence of mushrooms, and the most effective compound was cinnamaldehyde. Fumigation treatment with 5 μl l⁻¹ cinnamaldehyde decreased BI, delayed cap opening, reduced microorganism counts, promoted the accumulation of phenolics and ascorbic acid. In addition, 5 μl l⁻¹ cinnamaldehyde fumigation treatment inhibited the activities of PPO and POD, and increased PAL activity during the storage period. Thus, postharvest essential oil fumigation treatment has positive effects on improving the quality of button mushrooms. PMID:24295683

  2. Sublethal Heavy Metal Stress Stimulates Innate Immunity in Tomato

    Directory of Open Access Journals (Sweden)

    Nilanjan Chakraborty

    2015-01-01

    Full Text Available Effect of sublethal heavy metal stress as plant biotic elicitor for triggering innate immunity in tomato plant was investigated. Copper in in vivo condition induced accumulation of defense enzymes like peroxidase (PO, polyphenol oxidase (PPO, phenylalanine ammonia-lyase (PAL, and β-1,3 glucanase along with higher accumulation of total phenol, antioxidative enzymes (catalase and ascorbate peroxidase, and total chlorophyll content. Furthermore, the treatment also induced nitric oxide (NO production which was confirmed by realtime visualization of NO burst using a fluorescent probe 4,5-diaminofluorescein diacetate (DAF-2DA and spectrophotometric analysis. The result suggested that the sublethal dose of heavy metal can induce an array of plant defense responses that lead to the improvement of innate immunity in plants.

  3. Sethoxydim treatment inhibits lipid metabolism and enhances the accumulation of anthocyanins in rape (Brassica napus L.) leaves.

    Science.gov (United States)

    Belkebir, Aicha; Benhassaine-Kesri, Ghouziel

    2013-09-01

    Cyclohexanediones (e.g., sethoxydim) are known to be inhibitors of plastid acetyl-CoA carboxylase (ACCase) of monocotyledonous plants and provoke plant death. When rape leaves were treated with 10(-3) M sethoxydim, growth rate, chlorophyll and lipid contents were reduced, but plant resisted to herbicide. [1-(14)C] Acetate labelling showed that lipid synthesis was affected by sethoxydim, probably through inhibition of chloroplast homomeric ACCase activity, and the fatty acid synthase activity (FAS) was reduced because of malonyl-CoA deficiency. In contrast, sethoxydim treatment provoked an increase in phenylalanine ammonia lyase (PAL) activity with an accumulation of cinnamic acid, naringenin and anthocyanins. The accumulation of anthocyanins seems to reduce the damaging effect of the herbicide stress. Thus, in plant cell, the flux of carbon seems to be oriented towards protective mechanisms, and the two ACCases could have an important role in this orientation. PMID:25149245

  4. Effect of Salicylic Acid on Enzyme Activity in Wheat in Immediate Early Time after Infection with Mycosphaerella Graminicola

    Directory of Open Access Journals (Sweden)

    Gholamnezhad J.

    2016-03-01

    Full Text Available The effect of salicylic acid (SA on antioxidant enzymes activities in wheat infected with Mycosphaerella graminicola was investigated. Different concentrations of SA (0 and 2mM were sprayed on susceptible and tolerant cultivars of wheat at a two-leaf stage. Enhanced activities of peroxidase, catalase, phenylalanine ammonia lyase, and polyphenoloxidase were determined in two wheat SA-treated cultivars in the presence or absence of pathogen. The results showed that the application of SA was more effective on antioxidant activities than pathogen. However, the highest activities of all tested enzymes were detected in cultivars treated both with SA and pathogen. Although in the earliest time of infection the antioxidant enzymes activities in susceptible cultivar were weaker than in the tolerant cultivar, the enzymes activity enhancement by SA in susceptible cultivar was observable, too. These results suggest SA as plant defense inducer could be an effective agent against M. graminicola in wheat.

  5. Ethanolamine utilization in Vibrio alginolyticus

    Directory of Open Access Journals (Sweden)

    Khatri Neelam

    2012-12-01

    Full Text Available Abstract Ethanolamine is used as an energy source by phylogenetically diverse bacteria including pathogens, by the concerted action of proteins from the eut-operon. Previous studies have revealed the presence of eutBC genes encoding ethanolamine-ammonia lyase, a key enzyme that breaks ethanolamine into acetaldehyde and ammonia, in about 100 bacterial genomes including members of gamma-proteobacteria. However, ethanolamine utilization has not been reported for any member of the Vibrio genus. Our comparative genomics study reveals the presence of genes that are involved in ethanolamine utilization in several Vibrio species. Using Vibrio alginolyticus as a model system we demonstrate that ethanolamine is better utilized as a nitrogen source than as a carbon source. Reviewers This article was reviewed by Dr. Lakshminarayan Iyer and Dr. Vivek Anantharaman (nominated by Dr. L Aravind.

  6. Entropic and Dynamical Origins of Catalysis in a B12 Enzyme

    Science.gov (United States)

    Warncke, Kurt; Wang, Miao

    2010-03-01

    The kinetics of the diffusive radical pair separation process in the adenosylcobalamin (coenzyme B12) -dependent ethanolamine ammonia-lyase from Salmonella typhimurium at 234-248 K in a dimethylsulfoxide/water cryosolvent system [1] were determined by using time-resolved, full-spectrum electron paramagnetic resonance spectroscopy. Substrate hydrogen isotope effects show that the cofactor cobalt-carbon bond cleavage event rate is rate determining, and that catalysis (relative to solution) is almost entirely entropic. The results challenge the proposed, traditional enthalpy-based mechanisms, and show that delocalized, dynamical sources are central in bond cleavage catalysis. Changes in configurational freedom of surface residues and hydration waters are proposed as the microscopic origin. [1] M. Wang and K. Warncke, J. Am. Chem. Soc. 2008, 130, 4846.

  7. Cobalamin Catalytic Centers for Stable Fuels Generation from Carbon Dioxide

    Science.gov (United States)

    Robertson, Wesley D.; Jawdat, Benmaan I.; Ennist, Nathan M.; Warncke, Kurt

    2010-03-01

    Our aim is to design and construct protein-based artificial photosynthetic systems that reduce carbon dioxide (CO2) to stable fuel forms within the robust and adaptable (βα)8 TIM-barrel protein structure. The EutB subunit of the adenosylcobalamin-dependent enzyme, ethanolamine ammonia-lyase, from Salmonella typhimurium, was selected as the protein template. This system was selected because the Co^I forms of the native cobalamin (Cbl) cofactor, and the related cobinamide (Cbi), possess redox properties that are commensurate with reduction of CO2. The kinetics of photo- (excited 5'-deazariboflavin electron donor) and chemical [Ti(III)] reduction, and subsequent reaction, of the Cbl and Cbi with CO2 are measured by time-resolved UV/visible absorption spectroscopy. Products are quantified by NMR spectroscopy. The results address the efficacy of the organocobalt catalytic centers for CO2 reduction to stable fuels, towards protein device integration.

  8. Bio-Inspired Catalyst for CO2 Reduction

    Science.gov (United States)

    Bovell, Adonis; Warncke, Kurt

    2010-03-01

    A catalytic device for high specificity recognition and light-driven reduction of CO2 to energy rich biofuels is being developed by using the robust TIM barrel fold of the EutB subunit of the enzyme, ethanolamine-ammonia lyase (from Salmonella typhimurium), as a scaffold. The cobalt(I) form of the native cobalamin serves as the catalytic center. Results show that cobalamins bind with optimal micromolar affinity to purified EutB, and undergo reductive activation. Molecular biology techniques have been used to generate histidine-tagged EutB subunit for high throughput mutagenesis studies. Rational active site modifications of EutB have been made to satisfy the criteria of specific CO2 binding, reduction, and proton delivery.

  9. Rhodotorula glutinis-potential source of lipids, carotenoids, and enzymes for use in industries.

    Science.gov (United States)

    Kot, Anna M; Błażejak, Stanisław; Kurcz, Agnieszka; Gientka, Iwona; Kieliszek, Marek

    2016-07-01

    Rhodotorula glutinis is capable of synthesizing numerous valuable compounds with a wide industrial usage. Biomass of this yeast constitutes sources of microbiological oils, and the whole pool of fatty acids is dominated by oleic, linoleic, and palmitic acid. Due to its composition, the lipids may be useful as a source for the production of the so-called third-generation biodiesel. These yeasts are also capable of synthesizing carotenoids such as β-carotene, torulene, and torularhodin. Due to their health-promoting characteristics, carotenoids are commonly used in the cosmetic, pharmaceutical, and food industries. They are also used as additives in fodders for livestock, fish, and crustaceans. A significant characteristic of R. glutinis is its capability to produce numerous enzymes, in particular, phenylalanine ammonia lyase (PAL). This enzyme is used in the food industry in the production of L-phenylalanine that constitutes the substrate for the synthesis of aspartame-a sweetener commonly used in the food industry. PMID:27209039

  10. Activity of enzymes associated with the enzymatic browning of minimally processed potatoes

    Directory of Open Access Journals (Sweden)

    Maria Carolina Dario Vitti

    2011-10-01

    Full Text Available The purpose of the present study was to evaluate the effect of different potato cultivars and storage temperatures on the specific activity of phenylalanine ammonia-lyase (PAL, polyphenol oxidase (PPO and peroxidase (POD in minimally processed potatoes. Potato cultivars Agata, Asterix and Monalisa were selected, washed, peeled, diced, sanitized, centrifuged, vacuum- packed and stored at 5 and 15°C for 9 and 5 days, respectively. There was an increase in the enzymatic activity in all the cultivars stored at 15°C. The cultivars 'Agata' and 'Asterix' stored at 5ºC did not differ significantly between them for the PAL, PPO and POD activities. The PAL, PPO and POD activities were also influenced by the storage temperature. The cultivars Agata and Asterix were more suitable in minimal processing than 'Monalisa', which was more susceptible to oxidative browning.

  11. RESPONSE OF PHENOLIC METABOLISM INDUCED BY ALUMINIUM TOXICITY IN FAGOPYRUM ESCULENTUM MOENCH. PLANTS.

    Science.gov (United States)

    Smirnov, O E; Kosyan, A M; Kosyk, O I; Taran, N Yu

    2015-01-01

    Buckwheat genus (Fagopyrum Mill.) is one of the aluminium tolerant taxonomic units of plants. The aim of the study was an evaluation of the aluminium (50 μM effect on phenolic accumulation in various parts of buckwheat plants (Fagopyrum esculentum Moench). Detection of increasing of total phenolic content, changes in flavonoid and anthocyanin content and phenylalanine ammonia-lyase activity (PAL) were revealed over a period of 10 days of exposure to aluminium. The most significant effects of aluminium treatment on phenolic compounds accumulation were total phenolic content increasing (by 27.2%) and PAL activity rising by 2.5 times observed in leaves tissues. Received data could be helpful to understand the aluminium tolerance principles and relationships of phenolic compounds to aluminium phytotoxicity. PMID:27025067

  12. Role of Root Exudates in Adaptative Reactions of Buckwheat Plants in Aluminium-acid Stress

    Directory of Open Access Journals (Sweden)

    A.E. Smirnov

    2014-03-01

    Full Text Available Aliminium toxicity is major limiting factor of crop production in acidic soils. It is known that mechanisms of toxic effects of aluminium are differing in biochemical characters, research of aluminium toxicity complicated by variety of its chemical forms and migration in soil and water ability. The root exudates qualitative composition of common buckwheat was evaluated. Organic complexing agents – oxalic acid and phenolic compounds were revealed. The role of these complexing agents in the buckwheat aluminium resistance under acidic stress, participation in processes of external and internal detoxification was shown. Spectrophometric assay revealed an increase in root secretion of oxalic acid by 2.5 times and decrease in content of phenolic compounds in root exudates solution by 3 times upon aluminium (50 µM treatment. In the meanwhile the same concentration of the metal had induced phenylalanine ammonia-lyase activity by 2 times.

  13. INDUCTION OF SYSTEMIC RESISTANCE BY BIOCONTROL AGENTS AGAINST BACTERIAL BLIGHT OF COTTON CAUSED BY XANTHOMONAS CAMPESTRIS PV. MALVACEARUM

    Directory of Open Access Journals (Sweden)

    Niranjana S. Ramachandrappa

    2013-04-01

    Full Text Available Bioagents such as Trichoderma harzianum, Pseudomonas fluorescens and Bacillus subtilis were isolated from cotton rhizosphere soil and tested individually for their effectiveness in controlling bacterial blight of cotton caused by Xanthomonas campestris pv. malvacearum (Xcm. Talc based formulations were prepared and used for seed treatment at different concentrations for assessing their ability to stimulate plant growth and to control bacterial blight disease. Among bioagents, P. fluorescens and T. harzianum proved to be effective in controlling disease under field conditions.  Other than direct action, these bioagents triggered the defense related enzymes involved in synthesis of phenols. Higher activity of peroxidase, phenylalanine ammonia-lyase, polyphenol oxidase and b-1,3-glucanase was observed in P. fluorescens and T. harzianum treated cotton plants after challenge inoculation with Xcm. Seed treatment with these bioagents enhanced the seed germination and growth parameters against blight disease and they also induced systemic resistance in plant for defense mechanisms. 

  14. Inhibition of Trehalose Breakdown Increases New Carbon Partitioning into Cellulosic Biomass in Nicotiana tabacum

    Energy Technology Data Exchange (ETDEWEB)

    Best, F.M.; Ferrieri, R.; Best, F.M.; Koenig, K.; McDonald, K.; Schueller, M.J.; Rogers, A.; Ferrieri, R.A.

    2011-01-18

    Validamycin A was used to inhibit in vivo trehalase activity in tobacco enabling the study of subsequent changes in new C partitioning into cellulosic biomass and lignin precursors. After 12-h exposure to treatment, plants were pulse labeled using radioactive {sup 11}CO{sub 2}, and the partitioning of isotope was traced into [{sup 11}C]cellulose and [{sup 11}C]hemicellulose, as well as into [{sup 11}C]phenylalanine, the precursor for lignin. Over this time course of treatment, new carbon partitioning into hemicellulose and cellulose was increased, while new carbon partitioning into phenylalanine was decreased. This trend was accompanied by a decrease in phenylalanine ammonia-lyase activity. After 4 d of exposure to validamycin A, we also measured leaf protein content and key C and N metabolite pools. Extended treatment increased foliar cellulose and starch content, decreased sucrose, and total amino acid and nitrate content, and had no effect on total protein.

  15. Solidago canadensis L. Essential Oil Vapor Effectively Inhibits Botrytis cinerea Growth and Preserves Postharvest Quality of Strawberry as a Food Model System

    Science.gov (United States)

    Liu, Shumin; Shao, Xingfeng; Wei, Yanzhen; Li, Yonghua; Xu, Feng; Wang, Hongfei

    2016-01-01

    This study investigated the anti-fungal properties of Solidago canadensis L. essential oil (SCLEO) against Botrytis cinerea in vitro, and its ability to control gray mold and maintain quality in strawberry fruits. SCLEO exhibited dose-dependent antifungal activity against B. cinerea and profoundly altered mycelial morphology, cellular ultrastructure, and membrane permeability as evaluated by scanning electron microscopy, transmission electron microscopy, and fluorescence microscopy. SCLEO vapor at 0.1 mL/L maintained higher sensory acceptance and reduced decay of fresh strawberry fruit, and also reduced gray mold in artificially inoculated fruit. SCLEO treatment did not, however, stimulate phenylalanin ammonia-lyase, polyphenol oxidase, or chitinase, enzymes related to disease resistance. This suggests that SCLEO reduces gray mold by direct inhibition of pathogen growth. SCLEO vapor may provide a new and effective strategy for controlling postharvest disease and maintaining quality in strawberries. PMID:27531994

  16. Effect of Seed Bacterization on Plant Growth Response and Induction of Disease Resistance in Chilli

    Institute of Scientific and Technical Information of China (English)

    Yasmeen Siddiqui; Sariah Meon

    2009-01-01

    This study aimed to examine the induction of disease resistance, and growth response in chilli plants elicited by plant growth promoting endophytic bacteria [Pseudomonas aeruginosa (UPMP3), Burkholderia cepacia (UPMB3), and Serratia marcescens (UPMS3)]. Seed bacterization with UPMP3 and UPMB3 significantly increased peroxidase (PO),polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) activities. This increase corresponded to greater reduction in pre- and post-emergence damping-off caused by Sclerotium rolfsii. UPMS3 alone or as mixture with UPMP3 and UPMB3 did not show any significant reduction in disease incidence. However, all the isolates tested did not inhibit the seed germination and seedling establishment in chilli.

  17. De novo production of resveratrol from glucose or ethanol by engineered Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Li, Mingji; Kildegaard, Kanchana Rueksomtawin; Chen, Yun;

    2015-01-01

    Resveratrol is a natural antioxidant compound, used as food supplement and cosmetic ingredient. Microbial production of resveratrol has until now been achieved by supplementation of expensive substrates, p-coumaric acid or aromatic amino acids. Here we engineered the yeast Saccharomyces cerevisiae...... to produce resveratrol directly from glucose or ethanol via tyrosine intermediate. First we introduced the biosynthetic pathway, consisting of tyrosine ammonia-lyase from Herpetosiphon aurantiacus, 4-coumaryl-CoA ligase from Arabidopsis thaliana and resveratrol synthase from Vitis vinifera, and...... obtained 2.73±0.05 mg L−1 resveratrol from glucose. Then we over-expressed feedback-insensitive alleles of ARO4 encoding 3-deoxy-D-arabino-heptulosonate-7-phosphate and ARO7 encoding chorismate mutase, resulting in production of 4.85±0.31 mg L−1 resveratrol from glucose as the sole carbon source. Next we...

  18. Effects of root exudates of bivalent transgenic cotton (Bt+CpTI) plants on antioxidant proteins and growth of conventional cotton (Xinluhan 33).

    Science.gov (United States)

    Wu, Hong-Sheng; Shi, Xue; Li, Ji; Wu, Tian-Yu; Ren, Qian-Qi; Zhang, Zhen-Hua; Wang, Ming-Yan; Shang, Xiao-Xia; Liu, Yan; Xiao, Song-Hua

    2016-01-01

    A greenhouse experiment was conducted to assess the adverse impact of transgenic cotton on ecosystem and environment via effect of transgenic Bt+CpTI cotton root exudates on growth and antioxidant activity of conventional parental cotton. Results showed elevated reductive and oxidative species activities in the leaves of conventional parental cotton seedlings treated with varying concentrations of transgenic cotton root exudates. Compared to control, 14.9% to 39.9% increase in catalase, 8.8% to 114% increase in for peroxidase, 21.3% to 59.7% increase in phenylalanine ammonia-lyase and 5.8 to 19.5 fold in ascorbate specific peroxidase was observed. However, biomass and height of conventional cotton seedlings were not affected by any concentration of transgenic cotton root exudates. These results suggested that cultivation of transgenic Bt+CpTI cotton plants poses little risk to conventional parental cotton based on their root interactions. PMID:26930855

  19. Biochemical characterization of N-methyl N' -nitro-N-nitrosoguanidine-induced cadmium resistant mutants of Aspergillus niger

    Indian Academy of Sciences (India)

    Samar Kumar Pal; Tapan Kumar Das

    2005-12-01

    Two cadmium resistant mutants (Cd1 and Cd2) of Aspergillus niger, among the six isolated by mutagenization with N-methyl N′-nitro-N-nitrosoguanidine (MNNG) at pH 6.4 were selected for the study. Analysis of lipid composition of the mutants and the wildtype indicated that total lipid as well as individual lipids of the cadmium resistant mutants were changed as compared with that of the wildtype. The increased activities of metal-lothionein and reduced activities of D-xylose isomerase and L-phenylalanine ammonia lyase in cell free extract of the cadmium resistant mutants suggested that mutants could allow high concentration of cadmium salt as compared with that of the wildtype. The respiratory activity and intracellular as well as extracellular Cd2+ concentration of the mutants reflected the high tolerance of the Cd mutants to cadmium ion.

  20. Effect of 1-methylcyclopropene treatment on green asparagus quality during cold storage

    Science.gov (United States)

    Zhang, Peng; Zhang, Min; Wang, Shaojin; Wu, Zhishuang

    2012-10-01

    Green asparagus was treated with 1-methylcyclopropene at three concentration levels at room temperature for 24 h after harvest to evaluate the postharvest quality during cold storage at 4°C. Comparing with the controls, the loss of vitamin C, decomposition of chlorophyll, and accumulation of the malonydiadehyde under treatments of 1-methylcyclopropene were reduced during storage. The enzyme activities in asparagus including peroxidase and phenylalanine ammonia lyase were inhibited by 1-methylcyclopropene treatments, while the activity of superoxide dismutase was enhanced. Based on non-significant difference of the treated samples with 6 ìl l-1, 1-methylcyclopropene treatments at 4 ìl l-1 could be selected to maintain postharvest quality of green asparagus and provide long storage life.

  1. The effect of temperature on phenolic content in wounded carrots.

    Science.gov (United States)

    Han, Cong; Li, Jing; Jin, Peng; Li, Xiaoan; Wang, Lei; Zheng, Yonghua

    2017-01-15

    Reactive oxygen species (ROS) have been shown to play important roles in biosynthesis of phenolic antioxidants in wounded carrots. This study has gone further to understand the effects of storage temperature on phenolics accumulation in wounded carrots. The results indicated that both increased wounding intensity and higher storage temperature promoted the generation of ROS and enhanced phenolics accumulation in wounded carrots. Moreover, treatment with ROS inhibitor inhibited ROS generation, suppressed the activities of key enzymes in phenylpropanoid pathway (phenylalanine ammonia lyase, PAL; cinnamate-4-hydroxylase, C4H; 4-coumarate coenzyme A ligase, 4CL) and restrained phenolics accumulation in shredded carrots confirming previous reports. In contrast, treatment with ROS elicitor promoted ROS generation, enhanced the activities of PAL, C4H and 4CL, and induced phenolics accumulation. Thus, our results confirmed that ROS are essential for mediating wound-induced phenolics accumulation in carrots and suggested that increase temperature enhanced the accumulation of phenolics through inducing ROS generation. PMID:27542457

  2. Dicty_cDB: Contig-U15915-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 0.005 AL049500_7( AL049500 |pid:none) Arabidopsis thaliana DNA chromosom... 47 0.005 CU207211_2706( CU207211 |pid:none) Herminiimon...50 3e-04 A69644( A69644 ) threonine ammonia-lyase (EC 4.3.1.19) ilvA [simil... 50 4e-04 AB433985_1( AB433985 |pid:non...ed] - L... 60 3e-07 AH1694( AH1694 ) threonine dehydratase homolog ilvA [imported] - L... 60 3e-07 AF105341_1( AF105341 |pid:non...e) Pseudomonas aeruginosa PA7, com... 56 8e-06 CP000529_636( CP000529 |pid:none) Polaromonas naphthaleni...-05 AM260479_425( AM260479 |pid:none) Ralstonia eutropha H16 chromosom... 54 2e-05 CP000058_1597( CP000058 |pid:none) Pseudomon

  3. High-performance liquid chromatography determination of phenolic acids in potato tubers (Solanum tuberosum) during wound healing

    International Nuclear Information System (INIS)

    The content of phenolic acids formed during wound healing of gamma-irradiated and nonirradiated potato tubers was determined by HPLC. Chlorogenic acid, caffeic acid, p-coumaric acid, and ferulic acid were detected in small quantities in resting whole tubers of irradiated and nonirradiated potatoes. During wound healing their content increased many fold, and in addition, the neo and crypto isomers of chlorogenic acid accumulated in the wound healing tissue. The increased formation of phenolics was accompanied by a parallel rise in phenylalanine ammonia lyase activity. Chlorogenic acid contributed about 56% and together with the neo and crypto isomers accounted for 88% of the phenolics formed. Tubers irradiated to 100 Gy for sprout inhibition showed significantly lower levels of chlorogenic acid and its isomers during the first 8 days of wound healing. The results point to an impairment of wound-induced biosynthesis of phenolics in general and chlorogenic acid and its isomers in particular by irradiation

  4. AcEST: BP913601 [AcEST

    Lifescience Database Archive (English)

    Full Text Available ot sp_hit_id B1A925 Definition sp|B1A925|RPOC2_CARPA DNA-directed RNA polymerase subunit beta'' OS=Carica pa...9 8.2 >sp|B1A925|RPOC2_CARPA DNA-directed RNA polymerase subunit beta'' OS=Carica papaya GN=rpoC2 PE=3 SV=1 Length = 1387 Score...HLREILPI 487 >sp|O93967|PALY_AMAMU Phenylalanine ammonia-lyase OS=Amanita muscaria GN=PAL PE=2 SV=1 Length = 740 Score...dia farcinica GN=rpsO PE=3 SV=1 Length = 89 Score = 29.6 bits (65), Expect = 4.8 Id...E Rho guanine nucleotide exchange factor 18 OS=Mus musculus GN=Arhgef18 PE=2 SV=1 Length = 1021 Score = 30.0 bits (66), Expec

  5. Trichoderma harzianum L1 as a potential source for lytic enzymes and elicitor of defense responses in chickpea (Cicer arietinum L. against wilt disease caused by Fusarium oxysporum f. sp. ciceri.

    Directory of Open Access Journals (Sweden)

    Sreeramulu K

    2009-01-01

    Full Text Available The effect of some natural lignocellulosic substances on the production of ß-glucanase, chitinase, protease and xylanase from Trichoderma harzianum L1 has been studied under solid state fermentation conditions. Maximum activities of all these enzymes were observed in the fermentation medium containing the mixture of 1% rice bran, neem cake and 0.1% crab shell powder. The induction of plant defense response was investigated by inoculating the roots of chickpea cv JG62 with the biocontrol agent, T. harzianum L1. A root extract of chickpea inoculated with T. harzianum L1 showed increased activities of phenylalanine ammonia lyase and polyphenol oxidase, as well as induction of new trypsin and chymotrypsin inhibitors. The Fusarium oxysporum protease-2 was inhibited completely by root extract of chickpea inoculated with T. harzianum L1 and showed maximum resistance to rotting of roots caused by wilt disease

  6. Induction of nodD Gene in a Betarhizobium Isolate, Cupriavidus sp. of Mimosa pudica, by Root Nodule Phenolic Acids.

    Science.gov (United States)

    Mandal, Santi M; Chakraborty, Dipjyoti; Dutta, Suhrid R; Ghosh, Ananta K; Pati, Bikas R; Korpole, Suresh; Paul, Debarati

    2016-06-01

    A range of phenolic acids, viz., p-coumaric acid, 4-hydroxybenzaldehyde, 4-hydroxybenzoic acid, protocatechuic acid, caffeic acid, ferulic acid, and cinnamic acid have been isolated and identified by LC-MS analysis in the roots and root nodules of Mimosa pudica. The effects of identified phenolic acids on the regulation of nodulation (nod) genes have been evaluated in a betarhizobium isolate of M. pudica root nodule. Protocatechuic acid and p-hydroxybenzoic acid were most effective in inducing nod gene, whereas caffeic acid had no significant effect. Phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase activities were estimated, indicating regulation and metabolism of phenolic acids in root nodules. These results showed that nodD gene expression of betarhizobium is regulated by simple phenolic acids such as protocatechuic acid and p-hydroxybenzoic acid present in host root nodule and sustains nodule organogenesis. PMID:26897126

  7. Benzothiadiazole-Mediated Induced Resistance to Colletotrichum musae and Delayed Ripening of Harvested Banana Fruit.

    Science.gov (United States)

    Zhu, Xiaoyang; Lin, Huanzhang; Si, Zhenwei; Xia, Yihua; Chen, Weixin; Li, Xueping

    2016-02-24

    Benzothiadiazole (BTH) works as a plant activator. The effects of different BTH treatments and fungicides SPORGON on fruit ripening and disease incidence were investigated. The results showed that BTH treatment significantly delayed fruit ripening, maintained fruit firmness, color, and good fruit quality, and dramatically reduced the incidence of disease. BTH effectively inhibited the invasion and development of pathogenic bacteria and controlled the occurrence of disease. BTH treatment enhanced the activities of defense-related enzymes, including chitinase, phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase, increased the content of hydrogen peroxide and total antioxidant capacity, and reduced malondialdehyde content. Cellular structure analysis after inoculation confirmed that BTH treatment effectively maintained the cell structural integrity. SPORGON did not provide benefits for delaying fruit ripening or for the resistance system, while it can control the disease only during the earlier stage and not at later stages. PMID:26871966

  8. Dynamic changes in enzyme activities and phenolic content during in vitro rooting of tree peony (Paeonia suffruticosa Andr. plantlets

    Directory of Open Access Journals (Sweden)

    Songlin He

    2011-07-01

    Full Text Available The dynamic changes of phenolic content and peroxidase (POD, polyphenol oxidase (PPO, indole-3-acetic acid oxidase (IAAO and phenylalanine ammonia lyase (PAL activities were assessed during the in vitro rooting process of three cultivars of tree peony (Paeonia suffruticosa Andr.. These changes in enzyme-related activity and phenolic content__observed at the level of the whole plant__differed during the first 20 days of the rooting process in easy-to-root ‘Feng Dan Bai’ cultivar and difficult-to-root ‘Wu Long Peng Sheng’ and ‘Tai Ping Hong’ cultivars, and in most cases they were actually opposite. The ease with which ‘Feng Dan Bai’ was able to root was closely related to the activity of all four enzymes (POD, PPO, IAAO, PAL as well as to the phenolic content.

  9. AcEST: BP912788 [AcEST

    Lifescience Database Archive (English)

    Full Text Available |Q92Q48|Q92Q48_RHIME Putative outer membrane transmembrane pro... 35 2.0 tr|A5A5Y8|A5A5Y8_9POAL Phenylalan...AVDLRH--IEENVKSAVKSCVMTVAKKTLSTNSTGGLHVARFCEKDLL 567 >tr|Q92Q48|Q92Q48_RHIME Putative outer membrane trans...|A6U8K9|A6U8K9_SINMW Surface antigen (D15) OS=Sinorhizobium medicae (strain WSM419) GN=Smed_1138 PE=3 SV=1 ...12788 - Show BP912788 Clone id YMU001_000022_H04 Library YMU01 Length 495 Definition Adiantum capillus-vener...cterized protein OS=Oryza... 35 2.6 tr|A6MZG1|A6MZG1_ORYSI Phenyl ammonia lyase (Fragme

  10. Microbe-associated molecular pattern (MAMP) signatures, synergy, size and charge

    DEFF Research Database (Denmark)

    Aslam, Shazia N.; Erbs, Gitte; Morrissey, Kate L.; Newman, Mari-Anne; Chinchilla, Delphine; Boller, Thomas; Molinaro, Antonio; Jackson, Robert W.; Cooper, Richard M.

    2009-01-01

    (FLS2). MAMPs induce different calcium influx signatures, but these are concentration dependent and unlikely to explain the differential induction of defence genes [pathogenesis-related gene 1 (PR1), plant defensin gene 1.2 (PDF1.2) and phenylalanine ammonia lyase gene 1 (PAL1)] by flg22, elf18 and OGA...... of calcium influx and oxidative burst induced by non-saturating concentrations of bacterial MAMPs, used singly and in combination: flagellin peptide (flg22), elongation factor peptide (elf18), peptidoglycan (PGN) and component muropeptides, lipo-oligosaccharide (LOS) and core oligosaccharides. This....... The peptide MAMPs are potent elicitors at subnanomolar levels, whereas PGN and LOS at high concentrations induce low and late host responses. This difference might be a result of the restricted access by plant cell walls of MAMPs to their putative cellular receptors. flg22 is restricted by ionic...

  11. Plant defense genes are regulated by ethylene

    International Nuclear Information System (INIS)

    One of the earliest detectable events during plant-pathogen interaction is a rapid increase in ethylene biosynthesis. This gaseous plant stress hormone may be a signal for plants to activate defense mechanisms against invading pathogens such as bacteria, fungi, and viruses. The effect of ethylene on four plant genes involved in three separate plant defense response pathways was examined; these included (i and ii) genes that encode L-phenylalanine ammonia-lyase (EC 4.3.1.5) and 4-coumarate:CoA ligase [4-coumarate:CoA ligase (AMP-forming), EC 6.2.1.12], enzymes of the phenylpropanoid pathway, (iii) the gene encoding chalcone synthase, an enzyme of the flavonoid glycoside pathway, and (iv) the genes encoding hydroxyproline-rich glycoprotein, a major protein component(s) of plant cell walls. Blot hybridization analysis of mRNA from ethylene-treated carrot roots reveals marked increases in the levels of phenylalanine ammonia-lyase mRNA, 4-coumarate CoA ligase mRNA, chalcone synthase mRNA, and certain hydroxyproline-rich glycoprotein transcripts. The effect of ethylene on hydroxyproline-rich glycoprotein mRNA accumulation was different from that of wounding. Ethylene induces two hydroxyproline-rich glycoprotein mRNAs (1.8 and 4.0 kilobases), whereas wounding of carrot root leads to accumulation of an additional hydroxyproline-rich mRNA (1.5 kilobases). These results indicate that at least two distinct signals, ethylene and a wound signal, can affect the expression of plant defense-response genes

  12. Production of Cinnamic and p-Hydroxycinnamic Acids in Engineered Microbes.

    Science.gov (United States)

    Vargas-Tah, Alejandra; Gosset, Guillermo

    2015-01-01

    The aromatic compounds cinnamic and p-hydroxycinnamic acids (pHCAs) are phenylpropanoids having applications as precursors for the synthesis of thermoplastics, flavoring, cosmetic, and health products. These two aromatic acids can be obtained by chemical synthesis or extraction from plant tissues. However, both manufacturing processes have shortcomings, such as the generation of toxic subproducts or a low concentration in plant material. Alternative production methods are being developed to enable the biotechnological production of cinnamic and (pHCAs) by genetically engineering various microbial hosts, including Escherichia coli, Saccharomyces cerevisiae, Pseudomonas putida, and Streptomyces lividans. The natural capacity to synthesize these aromatic acids is not existent in these microbial species. Therefore, genetic modification have been performed that include the heterologous expression of genes encoding phenylalanine ammonia-lyase and tyrosine ammonia-lyase activities, which catalyze the conversion of l-phenylalanine (l-Phe) and l-tyrosine (l-Tyr) to cinnamic acid and (pHCA), respectively. Additional host modifications include the metabolic engineering to increase carbon flow from central metabolism to the l-Phe or l-Tyr biosynthetic pathways. These strategies include the expression of feedback insensitive mutant versions of enzymes from the aromatic pathways, as well as genetic modifications to central carbon metabolism to increase biosynthetic availability of precursors phosphoenolpyruvate and erythrose-4-phosphate. These efforts have been complemented with strain optimization for the utilization of raw material, including various simple carbon sources, as well as sugar polymers and sugar mixtures derived from plant biomass. A systems biology approach to production strains characterization has been limited so far and should yield important data for future strain improvement. PMID:26347861

  13. Biochemical and physiological responses of oil palm to bud rot caused by Phytophthora palmivora.

    Science.gov (United States)

    Moreno-Chacón, Andrés Leonardo; Camperos-Reyes, Jhonatan Eduardo; Ávila Diazgranados, Rodrigo Andrés; Romero, Hernán Mauricio

    2013-09-01

    In recent years, global consumption of palm oil has increased significantly, reaching almost 43 million tons in 2010. The sustainability of oil palm (Elaeis guineensis) cultivation has been compromised because of the bud rot disease whose initial symptoms are caused by Phytophthora palmivora. There was a significant incidence of the disease, from an initial stage 1 of the disease to the highest stage 5, that affected photosynthetic parameters, content of pigments, sugars, polyamines, enzymatic antioxidant activities, phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) and β-(1,3) glucanase (β-Gluc, EC 3.2.1.39). In healthy palms photosynthesis was 13.29 μmol CO2 m(-2) s(-1) in average, while in stage 5 the average photosynthesis was around 3.66 μmol CO2 m(-2) s(-1). Additionally, total chlorophyll was reduced by half at the last stage of the disease. On the contrary, the contents of putrescine, spermine and spermidine increased three, nine and twelve times with respect to stage 5, respectively. Antioxidant enzyme activities, as well as the phenylalanine ammonia-lyase and β-(1,3) glucanase showed an increase as the severity of the disease increased, with the latter increasing from 0.71 EAU in healthy palms to 2.60 EAU in plants at stage 5 of the disease. The peroxidase (POD, EC 1.11.1.7) enzymatic activity and the content of spermidine were the most sensitive indicators of disease. PMID:23796724

  14. Plant defense genes are regulated by ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Ecker, J.R.; Davis, R.W.

    1987-08-01

    One of the earliest detectable events during plant-pathogen interaction is a rapid increase in ethylene biosynthesis. This gaseous plant stress hormone may be a signal for plants to activate defense mechanisms against invading pathogens such as bacteria, fungi, and viruses. The effect of ethylene on four plant genes involved in three separate plant defense response pathways was examined; these included (i and ii) genes that encode L-phenylalanine ammonia-lyase (EC 4.3.1.5) and 4-coumarate:CoA ligase (4-coumarate:CoA ligase (AMP-forming), EC 6.2.1.12), enzymes of the phenylpropanoid pathway, (iii) the gene encoding chalcone synthase, an enzyme of the flavonoid glycoside pathway, and (iv) the genes encoding hydroxyproline-rich glycoprotein, a major protein component(s) of plant cell walls. Blot hybridization analysis of mRNA from ethylene-treated carrot roots reveals marked increases in the levels of phenylalanine ammonia-lyase mRNA, 4-coumarate CoA ligase mRNA, chalcone synthase mRNA, and certain hydroxyproline-rich glycoprotein transcripts. The effect of ethylene on hydroxyproline-rich glycoprotein mRNA accumulation was different from that of wounding. Ethylene induces two hydroxyproline-rich glycoprotein mRNAs (1.8 and 4.0 kilobases), whereas wounding of carrot root leads to accumulation of an additional hydroxyproline-rich mRNA (1.5 kilobases). These results indicate that at least two distinct signals, ethylene and a wound signal, can affect the expression of plant defense-response genes.

  15. PR Enzyme Activities of Cercospora theae Causing Bird’s Eye Spot Disease in Tea Plants (Camellia sinensis (L. O.kuntze

    Directory of Open Access Journals (Sweden)

    Rajendran Yazhini

    2011-01-01

    Full Text Available A total of three isolates of Cercospora theae namely KC10, MC24 and VC38 obtained from birds eye spot disease were used for the present study and subjected to various Pathogen Related (PR enzymatic secretion by the pathogen and the plant as a response to the disease attack. The enzyme secreted from the pathogen includes CMCase, amylase, invertase, pectinase and protease, its activity was studied at various incubation periods ranging from 15, 30, 60, 90 and 120 min. All enzymes except amylase, exhibited its maximal activity at 30 min incubation period whereas amylase exhibited its optimal activity at 60 min of incubation. The study revealed that C. theae was capable of producing the range of pathogenic enzymes and exhibited its maximal activity at 10th day harvest. The said enzyme activities was also studied in healthy and C. theae infected tea leaves including chitinase, DNase, Phenylalanine Ammonia Lyase (PAL, Tyrosine Ammonia Lyase (TAL, polyphenol oxidase (PPO, peroxidase (PO and catalase in order to detect the level of defensive response. The significance of the specific enzymatic activity detected in C. theae isolates and tea leaves were discussed by correlating to the plant pathogenesis. This study showed that phyopathogenic isolates of C. theae is capable of producing various carbohydrases, pectinases and protease and defensive enzymes along with phenolic and oxidative enzymes. The significance of correlating the enzymatic activity with the virulence of the isolates was ascertained and discussed. The enzyme profile studies of the pathogenic isolates assist in understanding and revealing of host-pathogen interaction.

  16. Effect of Lanthanum on Plants under Supplementary Ultraviolet-B Radiation: Effect of Lanthanum on Flavonoid Contents in Soybean Seedlings Exposed to Supplementary Ultraviolet-B Radiation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effect of La on flavonoids, chlorophyll contents, and phenylalanine ammonia-lyase (PAL) activity in soybean seedlings under supplementary ultraviolet-B radiation (UV-B, 280 ~ 320 nm) was studied. The results show that PAL activity, contents of flavonoids and chlorophyll in the plants pretreated with La (20 mg· L-1) are higher than those in CK. UV-B radiation could result in an increase in flavonoid content and PAL activity, associated with a decrease in chlorophyll content. However, the increase in the range of PAL activity and flavonoid content in UV-B treatment are lesser than those in the La treatment. The changes of flavonoid contents and PAL activity in La + UV-B treatment are similar to those in UV-B treatment, and the increase in their range is higher than those in UV-B treatment. This shows that La can enhance the resistance of soybean seedling to UV-B radiation and alleviate the damage of UV-B radiation by increasing flavonoid content, chlorophyll content, and PAL activity.

  17. Garlic exerts allelopathic effects on pepper physiology in a hydroponic co-culture system

    Directory of Open Access Journals (Sweden)

    Haiyan Ding

    2016-05-01

    Full Text Available A hydroponic co-culture system was adopted to determine the allelopathic potential of garlic on the growth of pepper plants. Different numbers of garlic plants (0, 2, 4, 8 and 12 were hydroponically co-cultured with two pepper plants to investigate allelopathic effects on the growth attributes and antioxidative defense system of the test pepper plants. The responses of the pepper plants depended on the number of garlic plants included in the co-culture system, indicating an association of pepper growth with the garlic root exudate concentration. When grown at a pepper/garlic ratio of 1:1 or 1:2, the pepper plant height, chlorophyll content, and peroxidase (POD, catalase (CAT and phenylalanine ammonia-lyase (PAL activities were significantly increased after 30 days of co-culture; in contrast, reduction in methane dicarboxylic aldehyde (MDA content was observed. However, when the pepper/garlic ratio was 1:4 or higher, these morphological indices and protective enzyme activities were significantly inhibited, whereas MDA levels in the pepper leaves were significantly increased due to severe membrane lipid peroxidation. The results indicate that although low concentrations of garlic root exudates appear to induce protective enzyme systems and promote pepper growth, high concentrations have deleterious effects. These findings suggest that further investigations should optimize the co-culture pepper/garlic ratio to reduce continuous cropping obstacles in pepper production.

  18. The Effect and Action Mechanisms of Oligochitosan on Control of Stem Dry Rot of Zanthoxylum bungeanum

    Science.gov (United States)

    Li, Peiqin; Cao, Zhimin; Wu, Zhou; Wang, Xing; Li, Xiuhong

    2016-01-01

    In this report, the effects of two oligochitosans, i.e., oligochitosan A (OCHA) and oligochitosan B (OCHB), on control of dry rot of Zanthoxylum bungeanum (Z. bungeanum) caused by Fusarium sambucinum (F. sambucinum) were evaluated. First, both oligochitosans show desirable ability to decrease the infection of F. sambucinum. Second, the oligochitosans strongly inhibit the radial colony and submerged biomass growth of F. sambucinum. Lastly, these oligochitosans are capable of increasing the activities of phenylalanine ammonia lyase (PAL), polyphenoloxidase (PPO) and peroxidase (POD) significantly, as well as enhancing the content of total phenolics in Z. bungeanum stems. These findings indicate that the protective effects of OCHA and OCHB on Z. bungeanum stems against dry rot may be associated with the direct fungitoxic function against pathogen and the elicitation of biochemical defensive responses in Z. bungeanum stems. The outcome of this report suggests that oligochitosans may serve as a promising natural fungicide to substitute, at least partially, for synthetic fungicides in the disease management of Z. bungeanum. PMID:27376270

  19. Biological Activity of Vegetal Extracts Containing Phenols on Plant Metabolism

    Directory of Open Access Journals (Sweden)

    Andrea Ertani

    2016-02-01

    Full Text Available The influence of vegetal extracts derived from red grape, blueberry fruits and hawthorn leaves on Zea mays L. plant growth and the activity of phenylalanine ammonia-lyase (PAL, a key enzyme of the phenylpropanoid pathway, was investigated in laboratory experiments. The extracts were characterized using FT-IR and Raman spectroscopies in order to obtain a pattern of the main functional groups. In addition, phenols content was determined by HPLC, whereas the content of indoleacetic acid and isopentenyladenosine hormones was determined by ELISA test and the auxin and gibberellin-like activities by plant-bioassays. The treated maize revealed increased root and leaf biomass, chlorophyll and sugars content with respect to untreated plants. Hawthorn, red grape skin and blueberry at 1.0 mL/L induced high p-coumaric content values, whilst hawthorn also showed high amounts of gallic and p-hydroxybenzoic acids. PAL activity induced by hawthorn at 1.0 mL/L had the highest values (11.1-fold UNT and was strongly and linearly related with the sum of leaf phenols. Our results suggest that these vegetal extracts contain more than one group of plant-promoting substances.

  20. Thiamine-induced priming against root-knot nematode infection in rice involves lignification and hydrogen peroxide generation.

    Science.gov (United States)

    Huang, Wen-Kun; Ji, Hong-Li; Gheysen, Godelieve; Kyndt, Tina

    2016-05-01

    Thiamine (vitamin B1, VB1) can act as a plant defence trigger, or priming agent, leading to a rapid counterattack on pathogen invasion. In this study, the priming effect of thiamine on rice (Oryza sativa cv. Nipponbare) and its activity against root-knot nematode (Meloidogyne graminicola) infection were evaluated. Thiamine treatment and subsequent nematode inoculation activated hydrogen peroxide (H2 O2 ) accumulation and lignin deposition in plant roots, and this correlated with enhanced transcription of OsPAL1 and OsC4H, two genes involved in the phenylpropanoid pathway. The number of nematodes in rice roots was slightly but significantly reduced, and the development of the nematodes was delayed, whereas no direct toxic effects of VB1 on nematode viability and infectivity were observed. The combined application of thiamine with l-2-aminooxy-3-phenylpropionic acid (AOPP), an inhibitor of phenylalanine ammonia-lyase (PAL), significantly hampered the VB1-priming capacity. These findings indicate that thiamine-induced priming in rice involves H2 O2 and phenylpropanoid-mediated lignin production, which hampers nematode infection. Further cellular and molecular studies on the mechanism of thiamine-induced defence will be useful for the development of novel nematode control strategies. PMID:27103216

  1. Expression of a Codon-Optimized dsdA Gene in Tobacco Plastids and Rice Nucleus Confers D-Serine Tolerance.

    Science.gov (United States)

    Li, Yanmei; Wang, Rui; Hu, Zongliang; Li, Hongcai; Lu, Shizhan; Zhang, Juanjuan; Lin, Yongjun; Zhou, Fei

    2016-01-01

    D-serine is toxic to plants. D-serine ammonia lyase, which is encoded by the dsdA gene, can attenuate this toxicity with high specificity. In the present study, we explored the function of codon-optimized dsdA with tobacco plastids and rice nuclear transformation system. It was shown that dsdA gene was site-specifically integrated into the tobacco plastid genome and displayed a high level of expression. Genetic analysis of the progenies showed that dsdA gene is maternally inherited and confers sufficient D-serine resistance in tobacco. The effective screening concentrations of D-serine for seed germination, callus regeneration and foliar spray were 10, 30, and 75 mM, respectively. In addition, calluses from homozygous transgenic rice lines also showed significant tolerance to D-serine (up to 75 mM). Our study proves the feasibility of using dsdA gene as a selectable marker in both plastid and nuclear transformation systems. PMID:27242842

  2. Expression of a codon-optimized dsdA gene in tobacco plastids and rice nuclear confers D-serine tolerance

    Directory of Open Access Journals (Sweden)

    Yanmei eLi

    2016-05-01

    Full Text Available D-serine is toxic to plants. D-serine ammonia lyase, which is encoded by the dsdA gene, can attenuate this toxicity with high specificity. In the present study, we explored the function of codon-optimized dsdA with tobacco plastids and rice nuclear transformation system. It was shown that the dsdA gene was site-specifically integrated into the tobacco chloroplast genome and displayed a high level of expression. Genetic analysis of the progenies showed that the dsdA gene is maternally inherited and confers sufficient D-serine resistance in tobacco. The effective screening concentrations of D-serine for seed germination, callus regeneration and foliar spray were 10 mM, 30 mM and 75 mM, respectively. In addition, calluses from homozygous transgenic rice lines also showed significant tolerance to D-serine (up to 75 mM. Our study proves the feasibility of using dsdA gene as a selectable marker in both chloroplast and nuclear transformation systems.

  3. Use of silicon as inductor of the resistance in potato to Myzus persicae (Sulzer) (Hemiptera: Aphididae)

    International Nuclear Information System (INIS)

    The aphid Myzus persicae (Sulzer) is an important pest of potato and causes direct harm, due to the quantity of sap extracted and for being vector of important phytovirus. This work was carried out to evaluate the action of silicon as a resistance inducer of potato to M. persicae. Four treatments were tried: foliar fertilization with silicon acid at 1%; soil fertilization with 250 ml silicic acid solution at 1%; foliar fertilization with silicon acid at 1% + soil fertilization with 250 ml silicic acid solution at 1%; and a control. The treatments were applied thirty days after the explants emergence. Fifteen days after the application of the treatments, feeding preference and some biological aspects of the aphids were evaluated. After, the content of tannins and lignin present in the leaves and the activity of the enzymes peroxidase and phenylalanine ammonia-lyase were also determined. The silicon fertilization did not affect the preference of the aphids; however it reduced fecundity and the rate of population growth of the insects. The lignin percentage increased in the leaves of plants fertilized with silicon via soil and/or foliar and the percentage of tannins increased only in the leaves fertilized via soil plus foliar. The silicon acted as a resistance inducer to M. persicae in potato. (author)

  4. Stress responses of duckweed (Lemna minor L.) and water velvet (Azolla filiculoides Lam.) to anionic surfactant sodium-dodecyl-sulphate (SDS).

    Science.gov (United States)

    Forni, C; Braglia, R; Harren, F J M; Cristescu, S M

    2012-04-01

    Surfactants are used for several purposes and recently they have attracted the attention for their ability to modify the behavior of other preexistent or co-disposed contaminants, although their use or discharge in wastewaters can represent a real or potential risk for the environment. Lemna minor L. and Azolla filiculoides Lam. are floating aquatic macrophytes, very effective in accumulating several pollutants including sodium dodecyl sulphate (SDS). In this work we evaluated the effects of SDS on these species by determining the stress ethylene production via laser-based trace gas detection, and the activities of enzymes involved in stress response, such as guaiacol peroxidase (G-POD), phenylalanine ammonia-lyase (PAL) and polyphenol-oxidase (PPO). Phenolics content was also determined. The macrophytes were treated with different concentrations of SDS for one week. SDS affected duckweed enzymatic activities and phenol content. While in the fern phenolics amount, PAL, G-POD and PPO activities were not affected by SDS except for 100 ppm SDS, the only concentration that was taken up and not completely degraded. Stress ethylene production was induced only in the fern treated with 50 and 100 ppm SDS. PMID:22277247

  5. Involvement of Jasmonate- signaling pathway in the herbivore-induced rice plant defense

    Institute of Scientific and Technical Information of China (English)

    XU Tao; ZHOU Qiang; CHEN Wei; ZHANG Guren; HE Guofeng; GU Dexiang; ZHANG Wenqing

    2003-01-01

    The expression patterns of eight defense- related genes in the herbivore-infested and jasmonate- treated (jasmonic acid, JA and its derivative MeJA) rice leaves were analyzed using RT-PCR. The results showed that Spodoptera litura Fabricius (Lepidoptera: Noctuidae) herbivory induced the expression of lipoxygenase (LOX) and allene oxide synthase (AOS) genes that are involved in the jasmonate-signaling pathway. Moreover, S. Litura damage resulted in the expression of farnesyl pyrophosphate synthase (FPS), Bowman-birk proteinase inhibitor (BBPI), phenylalanine ammonia-lyase (PAL) and other rice defense- related genes that were also induced by aqueous JA treatment or gaseous MeJA treatment. These indicated that in rice leaves, the JA-related signaling pathway was involved in the S. Litura-induced chemical defense. Mechanical damage and brown planthopper (BPH), Nilaparvata lugens (Stal) (Homoptera: Delphacidae) damage induced the expression of LOX gene, but both treatments did not induce the expression of AOS gene. However, BPH damage induced the expression of acidic pathogen-related protein 1 (PR-1a), Chitinase (PR-3), and PAL genes, which is involved in the salicylate- signaling pathway. It was suggested that salicylate-related signaling pathway or other pathways, rather than jasmonate-signaling pathway was involved in the BPH-induced rice plant defense.

  6. Defense Responses in Rice Induced by Silicon Amendment against Infestation by the Leaf Folder Cnaphalocrocis medinalis

    Science.gov (United States)

    Han, Yongqiang; Li, Pei; Gong, Shaolong; Yang, Lang; Wen, Lizhang; Hou, Maolin

    2016-01-01

    Silicon (Si) amendment to plants can confer enhanced resistance to herbivores. In the present study, the physiological and cytological mechanisms underlying the enhanced resistance of plants with Si addition were investigated for one of the most destructive rice pests in Asian countries, the rice leaf folder, Cnaphalocrocis medinalis (Guenée). Activities of defense-related enzymes, superoxide dismutase, peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase, and concentrations of malondialdehyde and soluble protein in leaves were measured in rice plants with or without leaf folder infestation and with or without Si amendment at 0.32 g Si/kg soil. Silicon amendment significantly reduced leaf folder larval survival. Silicon addition alone did not change activities of defense-related enzymes and malondialdehyde concentration in rice leaves. With leaf folder infestation, activities of the defense-related enzymes increased and malondialdehyde concentration decreased in plants amended with Si. Soluble protein content increased with Si addition when the plants were not infested, but was reduced more in the infested plants with Si amendment than in those without Si addition. Regardless of leaf folder infestation, Si amendment significantly increased leaf Si content through increases in the number and width of silica cells. Our results show that Si addition enhances rice resistance to the leaf folder through priming the feeding stress defense system, reduction in soluble protein content and cell silicification of rice leaves. PMID:27124300

  7. Probing the Active Site of MIO-dependent Aminomutases, Key Catalysts in the Biosynthesis of amino Acids Incorporated in Secondary Metabolites

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, H.; Bruner, S

    2010-01-01

    The tyrosine aminomutase SgTAM produces (S)-{beta}-tyrosine from L-tyrosine in the biosynthesis of the enediyne antitumor antibiotic C-1027. This conversion is promoted by the methylideneimidazole-5-one (MIO) prosthetic group. MIO was first identified in the homologous family of ammonia lyases, which deaminate aromatic amino acids to form {alpha},{beta}-unsaturated carboxylates. Studies of substrate specificity have been described for lyases but there have been limited reports in altering the substrate specificity of aminomutases. Furthermore, it remains unclear as to what structural properties are responsible for catalyzing the presumed readdition of the amino group into the {alpha},{beta}-unsaturated intermediates to form {beta}-amino acids. Attempts to elucidate specificity and mechanistic determinants of SgTAM have also proved to be difficult as it is recalcitrant to perturbations to the active site via mutagenesis. An X-ray cocrystal structure of the SgTAM mutant of the catalytic base with L-tyrosine verified important substrate binding residues as well as the enzymatic base. Further mutagenesis revealed that removal of these crucial interactions renders the enzyme inactive. Proposed structural determinants for mutase activity probed via mutagenesis, time-point assays and X-ray crystallography revealed a complicated role for these residues in maintaining key quaternary structure properties that aid in catalysis.

  8. Probing the active site of MIO-dependent aminomutases, key catalysts in the biosynthesis of beta-amino acids incorporated in secondary metabolites.

    Science.gov (United States)

    Cooke, Heather A; Bruner, Steven D

    2010-09-01

    The tyrosine aminomutase SgTAM produces (S)-ss-tyrosine from L-tyrosine in the biosynthesis of the enediyne antitumor antibiotic C-1027. This conversion is promoted by the methylideneimidazole-5-one (MIO) prosthetic group. MIO was first identified in the homologous family of ammonia lyases, which deaminate aromatic amino acids to form alpha,ss-unsaturated carboxylates. Studies of substrate specificity have been described for lyases but there have been limited reports in altering the substrate specificity of aminomutases. Furthermore, it remains unclear as to what structural properties are responsible for catalyzing the presumed readdition of the amino group into the alpha,ss-unsaturated intermediates to form ss-amino acids. Attempts to elucidate specificity and mechanistic determinants of SgTAM have also proved to be difficult as it is recalcitrant to perturbations to the active site via mutagenesis. An X-ray cocrystal structure of the SgTAM mutant of the catalytic base with L-tyrosine verified important substrate binding residues as well as the enzymatic base. Further mutagenesis revealed that removal of these crucial interactions renders the enzyme inactive. Proposed structural determinants for mutase activity probed via mutagenesis, time-point assays and X-ray crystallography revealed a complicated role for these residues in maintaining key quaternary structure properties that aid in catalysis. PMID:20577998

  9. Bioreactor production of secondary metabolites from cell cultures of periwinkle and sandalwood.

    Science.gov (United States)

    Valluri, Jagan V

    2009-01-01

    A bench-top bioreactor allowing continuous extraction of secondary metabolites is designed for Catharanthus roseus L. (G.) Don (periwinkle) and Santalum album L. (sandalwood) plant cell suspensions. Periwinkle cell cultures are exposed to biotic elicitors (Aspergillus niger, crude chitin) and abiotic elicitors (mannitol, methyl jasmonate) to induce alkaloid production. Whereas most of the biotic elicitors are effective when added on day 15 of culture, the abiotic elicitors are effective when added on day 20. The use of trans-cinnamic acid, an inhibitor of phenylalanine ammonia lyase (PAL) activity, results in significant increase in the alkaloid production of periwinkle cell cultures. Exposure of the cells to mannitol-induced osmotic stress produced marked increment in the total alkaloid production. When biotic and abiotic stress treatments are applied sequentially, an additive effect in alkaloid accumulation is observed. Although no essential oils are detected, secondary metabolites in the form of phenolics are produced by the sandalwood cell cultures in the bioreactor environment. The use of morphologic modification such as organ cultures and transformed cultures is believed to be required for both production and storage of essential oil constituents in sandalwood. The present chapter demonstrates that periwinkle and sandalwood cell suspensions could be developed and successfully cultured in a modified air-lift bioreactor. The exploitation of variant cell strains and biotransformation of added precursors can certainly improve the use of periwinkle and sandalwood cell cultures for the bioproduction of desired compounds. PMID:19521856

  10. Kaolin exogenous application boosts antioxidant capacity and phenolic content in berries and leaves of grapevine under summer stress.

    Science.gov (United States)

    Dinis, L-T; Bernardo, S; Conde, A; Pimentel, D; Ferreira, H; Félix, L; Gerós, H; Correia, C M; Moutinho-Pereira, J

    2016-02-01

    Heat waves, high light intensities and water deficit are becoming important threats in many important viticultural areas worldwide, so the implementation of efficient and cost-effective mitigation strategies is crucial for the production of premium wines while maintaining productivity. In this context, the foliar application of kaolin, a chemically inert mineral with excellent reflective properties, is being developed and experimented as a strategy to reduce the impact of heat and drought in Douro vineyards (Northern Portugal), already revealing promising results. In the present study we investigated if an improved antioxidant capacity is part of the beneficial effects of kaolin, by studying changes in the enzymatic and nonenzymatic antioxidant system in leaves and berries (cv Touriga Nacional). Results showed that mature grape berries contained higher amounts of total phenols (40%), flavonoids (24%), anthocyanins (32%) and vitamin C (12%) than fruits from control vines, and important changes were also measured in leaves. In parallel, kaolin application improved the antioxidant capacity in berries, which was correlated with the observed increased content in secondary metabolites. Kaolin application also regulated secondary metabolism at the transcriptional level through the increase in the transcript abundance of genes encoding phenylalanine ammonia lyase and chalcone synthase. PMID:26717011

  11. Synergistic Accumulative Effect of Salicylic Acid and Dibutyl Phthalate on Paclitaxel Production in Corylus avellana Cell Culture

    Directory of Open Access Journals (Sweden)

    Rezaei, A.

    2013-02-01

    Full Text Available Suspension cell cultures of Corylus avellana were challenged with salicylic acid and its combined use with dibutyl phthalate solvent. Salicylic acid with concentrations of 12.5, 25 and 50 mg L–1 and 10% (v/v dibutyl phthalate were used and added on day 8 and 10 of subculture, respectively. The results showed that growth, viability and protein content of cells were decreased by the treatments, compared to control. In all treatments, hydrogen peroxide content and lipid peroxidation rate of cells increased, compared to those of the control cells. Activity of phenylalanine ammonia-lyase increased by salicylic acid and, dibutyl phthalate exaggerated effect of salicylic acid. While flavonoids content decreased by the treatments, paclitaxel content increased significantly. The extracellular paclitaxel was more affected, compared to cell-associated paclitaxel and all treatments increased paclitaxel release and specific yield compared to that of the control. The most production of paclitaxel and specific yield of it were observed under effect of combined use of salicylic acid (50 mg L–1 and dibutyl phthalate, suggesting a synergistic accumulative effect.

  12. Prunus domestica pathogenesis-related protein-5 activates the defense response pathway and enhances the resistance to fungal infection.

    Directory of Open Access Journals (Sweden)

    Ashraf El-kereamy

    Full Text Available Pathogenesis-related protein-5 (PR-5 has been implicated in plant disease resistance and its antifungal activity has been demonstrated in some fruit species. However, their roles, especially their interactions with the other defense responses in plant cells, are still not fully understood. In this study, we have cloned and characterized a new PR-5 cDNA named PdPR5-1 from the European plum (Prunus domestica. Expression of PdPR5-1 was studied in different cultivars varying in resistance to the brown rot disease caused by the necrotrophic fungus Monilinia fructicola. In addition transgenic Arabidopsis, ectopically expressing PdPR5-1 was used to study its role in other plant defense responses after fungal infection. We show that the resistant cultivars exhibited much higher levels of transcripts than the susceptible cultivars during fruit ripening. However, significant rise in the transcript levels after infection with M. fructicola was observed in the susceptible cultivars too. Transgenic Arabidopsis plants exhibited more resistance to Alternaria brassicicola. Further, there was a significant increase in the transcripts of genes involved in the phenylpropanoid biosynthesis pathway such as phenylalanine ammonia-lyase (PAL and phytoalexin (camalexin pathway leading to an increase in camalexin content after fungal infection. Our results show that PdPR5-1 gene, in addition to its anti-fungal properties, has a possible role in activating other defense pathways, including phytoalexin production.

  13. Plants as biofactories: physiological role of reactive oxygen species on the accumulation of phenolic antioxidants in carrot tissue under wounding and hyperoxia stress.

    Science.gov (United States)

    Jacobo-Velázquez, Daniel A; Martínez-Hernández, Ginés B; Del C Rodríguez, Silvia; Cao, Cong-Mei; Cisneros-Zevallos, Luis

    2011-06-22

    Plants subjected to postharvest abiotic stresses synthesize secondary metabolites with health-promoting properties. Here, we report the potential use of carrots (Daucus carota) as biofactories of caffeoylquinic acids when subjected to wounding and hyperoxia stresses. Wounding stress induced an increase of ∼287% in total phenolic content (PC) in carrots stored for 48 h at 20 °C. This increase was higher (∼349%) in the wounded tissue treated with hyperoxia stress. To further understand the physiological role of reactive oxygen species (ROS) as a signaling molecule for the stress-induced accumulation of phenolics in carrots, the respiration rate as well as the enzymatic activities of NADPH oxidase, superoxide dismutase, ascorbate peroxidase, and catalase were evaluated. Likewise, shredded carrots were treated with diphenyleneiodonium chloride solution to block NADPH oxidase ROS productions, and the phenylalanine ammonia lyase activity and total PC were evaluated. Results demonstrated that ROS play a key role as a signaling molecule for the stress-induced accumulation of PC in carrots. PMID:21553806

  14. Changes in the content and biosynthesis of phytoalexins in banana fruit.

    Science.gov (United States)

    Kamo, T; Hirai, N; Tsuda, M; Fujioka, D; Ohigashi, H

    2000-10-01

    Changes in the phytoalexin content in unripe fruit of banana, Musa acuminata, were analyzed after various treatments. The results show that level of hydroxyanigorufone started to increase 1-2 day after either wounding or inoculation with conidia of Colletotrichum musae. Inoculation followed by wounding induced the formation of many other phenylphenalenones. The accumulation of hydroxyanigorufone decreased, after its transient maximum, on ripening by exposure of the wounded fruit to ethylene. The level of production of hydroxyanigorufone in ripe fruit treated by wounding and/or by inoculation was much lower than that in unripe fruit. 2-Aminooxyacetic acid, an inhibitor of phenylalanine ammonia-lyase (PAL), inhibited the accumulation of hydroxyanigorufone in wounded fruit, and the PAL activity increased after wounding and ethylene treatment, respectively. Feeding experiments with [1-(13)C] and [2-(13)C]cinnamic acids, and [2-(13)C]malonate show that two molecules of cinnamic acid and one of malonate were incorporated into each molecule of hydroxyanigorufone. The phytoalexins isolated from fruit to which deuterated hydroxyanigorufone and irenolone had been administered revealed that 2-(4'-hydroxyphenyl)-1,8-naphthalic anhydride was biosynthesized from hydroxyanigorufone rather than from irenolone. PMID:11129580

  15. Conservation, Divergence, and Genome-Wide Distribution of PAL and POX A Gene Families in Plants

    Directory of Open Access Journals (Sweden)

    H. C. Rawal

    2013-01-01

    Full Text Available Genome-wide identification and phylogenetic and syntenic comparison were performed for the genes responsible for phenylalanine ammonia lyase (PAL and peroxidase A (POX A enzymes in nine plant species representing very diverse groups like legumes (Glycine max and Medicago truncatula, fruits (Vitis vinifera, cereals (Sorghum bicolor, Zea mays, and Oryza sativa, trees (Populus trichocarpa, and model dicot (Arabidopsis thaliana and monocot (Brachypodium distachyon species. A total of 87 and 1045 genes in PAL and POX A gene families, respectively, have been identified in these species. The phylogenetic and syntenic comparison along with motif distributions shows a high degree of conservation of PAL genes, suggesting that these genes may predate monocot/eudicot divergence. The POX A family genes, present in clusters at the subtelomeric regions of chromosomes, might be evolving and expanding with higher rate than the PAL gene family. Our analysis showed that during the expansion of POX A gene family, many groups and subgroups have evolved, resulting in a high level of functional divergence among monocots and dicots. These results will act as a first step toward the understanding of monocot/eudicot evolution and functional characterization of these gene families in the future.

  16. Monitoring the Expression of Maize Genes in Developing Kernels under Drought Stress using Oligo-microarray

    Institute of Scientific and Technical Information of China (English)

    Meng Luo; Jia Liu; R. Dewey Lee; Brian T. Scully; Baozhu Guo

    2010-01-01

    Preharvest aflatoxin contamination of grain grown on the US southeastern Coast Plain is provoked and aggravated by abiotic stress. The primary abiotic stress is drought along with high temperatures. The objectives of the present study were to monitor gene expression in developing kernels in response to drought stress and to identify drought-responsive genes for possible use in germplasm assessment. The maize breeding line Tex6 was used, and gene expression profiles were analyzed in developing kernels under drought stress verses well-watered conditions at the stages of 25, 30, 35, 40, 45 d after pollination (DAP) using the 70 mer maize oligo-arrays. A total of 9 573 positive array spots were detected with unique gene IDs, and 7 988 were common in both stressed and well-watered samples. Expression patterns of some genes in several stress response-associated pathways, including abscisic acid, jasmonic acid and phenylalanine ammonia-lyase, were examined, and these specific genes were responsive to drought stress positively. Real-time quantitative polymerase chain reaction validated microarray expression data.The comparison between Tex6 and B73 revealed that there were significant differences in specific gene expression, patterns and levels. Several defense-related genes had been downregulated, even though some defense-related or drought responsive genes were upregulated at the later stages.

  17. Effects of clove essential oil and eugenol on quality and browning control of fresh-cut lettuce.

    Science.gov (United States)

    Chen, Xiangning; Ren, Lupei; Li, Menglin; Qian, Jia; Fan, Junfeng; Du, Bin

    2017-01-01

    This study confirmed the inhibitory effects of clove essential oil (CEO) and eugenol (EUG) on the browning and relevant enzymes of fresh-cut lettuce, and examined associated mechanisms by inhibition kinetics and computational docking analysis. Fresh-cut lettuce was treated with 0.05% CEO and 0.05% EUG solutions, resulting in inhibition of the deterioration of texture quality and browning of the lettuce surface and interior. Compared with the controls, CEO and EUG significantly inhibited the activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD, all p<0.05). EUG suppressed PAL, PPO, and POD in vitro in a dose-dependent manner, with IC50 values of 5.4±0.9, 29.5±3.5, and 61.9±6.7mM, respectively. The binding and inhibition effects of EUG on PAL, PPO, and POD, determined by inhibition kinetics and computational docking analysis, established EUG as a competitive inhibitor of these browning-relevant enzymes. PMID:27507495

  18. Simultaneous and selective decarboxylation of L-serine and deamination of L-phenylalanine in an amino acid mixture--a means of separating amino acids for synthesizing biobased chemicals.

    Science.gov (United States)

    Teng, Yinglai; Scott, Elinor L; Witte-van Dijk, Susan C M; Sanders, Johan P M

    2016-01-25

    Amino acids (AAs) obtained from the hydrolysis of biomass-derived proteins are interesting feedstocks for the chemical industry. They can be prepared from the byproduct of biofuel production and agricultural wastes. They are rich in functionalities needed in petrochemicals, providing the opportunity to save energy, reagents, and process steps. However, their separation is required before they can be applied for further applications. Electrodialysis (ED) is a promising separation method, but its efficiency needs to be improved when separating AAs with similar isoelectric points. Thus, specific conversions are required to form product with different charges. Here we studied the enzymatic conversions which can be used as a means to aid the ED separation of neutral AAs. A model mixture containing L-serine, L-phenylalanine and L-methionine was used. The reactions of L-serine decarboxylase and L-phenylalanine ammonia-lyase were employed to specifically convert serine and phenylalanine into ethanolamine and trans-cinnamic acid. At the isoelectric point of methionine (pH 5.74), the charge of ethanolamine and trans-cinnamic acid are +1 and -1, therefore facilitating potential separation into three different streams by electrodialysis. Here the enzyme kinetics, specificity, inhibition and the operational stabilities were studied, showing that both enzymes can be applied simultaneously to aid the ED separation of neutral AAs. PMID:25976628

  19. Evaluation of PAL activity, Phenolic and Flavonoid Contents in Three Pistachio (Pistacia vera L. Cultivars Grafted onto Three Different Rootstocks

    Directory of Open Access Journals (Sweden)

    N. Nadernejad

    2013-08-01

    Full Text Available Phenylalanine ammonia lyase (PAL is a biochemical marker of the environmental stress and plays a pivotal role in phenolic synthesis. The lower ROS level and oxidative damage was observed in grafted plants and the rootstocks have a profound influence on the biochemical composition, especially phenolic compounds. Regarding the importance of the effect rootstocks have on scion in pistachio trees, this study was carried out to assess and compare three pistachio cultivars ("Ahmadaghaii", "Ohadi" and "Kallehghuchi" on three rootstocks (Mutica, Ahli, Sarakhs. PAL activity, phenolic compounds, flavonoid and anthocyanin contents in leaves, flowers and fruits were measured toward the selection of the most suitable and compatible rootstock/scion resistant to environmental stresses. The results showed that PAL activity was different among the cultivars and organs. A positive correlation was observed between PAL activity and phenolic compounds in the leaves and flowers of Mutica- Ahmadaghaii, suggesting that it is more resistant than the others to environmental stresses. PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began. The hulls of the pistachio fruits contained high levels of phenolic compounds especially in Mutica-Ahmadaghaii suggesting its function as a protective layer and a defense chemical against ultraviolet radiation and pathogen. Our results indicated the presence of a number of bioactive compounds in kernels with the highest amount belonging to Mutica- Ahmadaghaii, and therefore it is concluded that pistachio rootstocks may affect the antioxidant compounds in kernels.

  20. The Relationship of Color Formation with Related Enzymes and Protein Contents in the Seedcoat of Oilseed Rape (Brassica napus)

    Institute of Scientific and Technical Information of China (English)

    LIANG Ying; LI Jia-na

    2004-01-01

    Three pairs of near-isogenic lines with different genetic backgrounds of yellow-seeded and black-seeded rape (Brassica napus L.) were used as experiment materials to study the relationship of color formation in the seedcoat with enzyme activity and protein content in it. The results showed that with similar genetic backgrounds, phenylalanine ammonia-lyase (PAL) and polyphenol oxidase(PPO) activities in the black-seeded lines were much higher than in their yellow-seeded counterparts and maximum PAL activity in the seedcoat occurred comparatively late while no significant difference was present in glutamine synthetase (GS) between the two types of rape. The plants were treated with red light,blue light, p-hydroxybenzoic acid (a PAL inhibitor), polyvinylpyridoxal (a PPO inhibitor),urea (a protein synthesis promoter) or chloramphenicol (CM, a plastid protein synthesis inhibitor) during seed development. It is speculated that PAL may be primarily responsible for coloration in the yellow seed; PPO may be the main factor contributing to the darkness of the testa of the black genotypes; and nitrogen assimilation is, probably, not directly related to the difference in protein content observed between yellow- and black-seeded genotypes, which may be induced mainly by PAL.

  1. A novel protein elicitor (SsCut) from Sclerotinia sclerotiorum induces multiple defense responses in plants.

    Science.gov (United States)

    Zhang, Huajian; Wu, Qun; Cao, Shun; Zhao, Tongyao; Chen, Ling; Zhuang, Peitong; Zhou, Xiuhong; Gao, Zhimou

    2014-11-01

    In this study, we report the cloning of the SsCut gene encoding cutinase from Sclerotinia sclerotiorum. We isolated a 609-bp cDNA encoding a polypeptide of 202 amino acids with a molecular weight of 20.4 kDa. Heterologous expression of SsCut in Escherichia coli (His-SsCut) caused the formation of lesions in tobacco that closely resembled hypersensitive response lesions. Mutational analysis identified the C-terminal-half peptide and the same amino acids indispensable for both enzyme and elicitor activity. His-SsCut was caused cell death in Arabidopsis, soybean (Glycine max), oilseed rape (Brassica napus), rice (Oryza sativa), maize (Zea mays), and wheat (Triticum aestivum), indicating that both dicot and monocot species are responsive to the elicitor. Furthermore, the elicitation of tobacco was effective in the induction of the activities of hydrogen peroxide, phenylalanine ammonia-lyase, peroxides, and polyphenol oxidase. His-SsCut-treated plants exhibited enhanced resistance as indicated by a significant reduction in the number and size of S. sclerotiorum, Phytophthora sojae, and P. nicotianae lesions on leaves relative to controls. Real-time PCR results indicated that the expression of defense-related genes and genes involved in signal transduction were induced by His-SsCut. Our results demonstrate that SsCut is an elicitor that triggers defense responses in plants and will help to clarify its relationship to downstream signaling pathways that induce defense responses. PMID:25149470

  2. Concurrent synthesis and release of nod-gene-inducing flavonoids from alfalfa roots

    International Nuclear Information System (INIS)

    Flavonoid signals from alfalfa (Medicago sativa L.) induce transcription of nodulation (nod) genes in Rhizobium meliloti. Alfalfa roots release three major nod-gene inducers: 4',7-dihydroxyflavanone, 4',7-dihydroxyflavone, and 4,4'-dihydroxy-2'-methoxychalcone. The objective of the present study was to define temporal relationships between synthesis and exudation for those flavonoids. Requirements for concurrent flavonoid biosynthesis were assessed by treating roots of intact alfalfa seedlings with [U-14C]-L-phenylalanine in the presence or absence of the phenylalanine ammonia-lyase inhibitor L-2-aminoxy-3-phenylpropionic acid (AOPP). In the absence of AOPP, each of the three flavonoids in exudates contained 14C. In the presence of AOPP, 14C labeling and release of all the exuded nod-gene inducers were reduced significantly. AOPP inhibited labeling and release of the strongest nod-gene inducer, methoxychalcone, by more than 90%. The release process responsible for exudation of nod-gene inducers appears to be specific rather than a general phenomenon such as a sloughing off of cells during root growth

  3. Reversible S-nitrosylation limits over synthesis of fungal styrylpyrone upon nitric oxide burst.

    Science.gov (United States)

    Zhao, Yanxia; He, Meihong; Xi, Qi; Ding, Jianing; Hao, Baixia; Keller, Nancy P; Zheng, Weifa

    2016-05-01

    Nitric oxide (NO) is known to be involved in modulating production of styrylpyrone polyphenols in the basidiomycete Inonotus obliquus. However, it remains unknown how NO orchestrates fungal styrylpyrone biosynthesis. Here, we show that a transient NO burst correlated with an enhanced expression of phenylalanine ammonia lyase (PAL), 4-coumarate CoA ligase (4CL), and styrylpyrone synthase (SPS), the key enzymes involved in styrylpyrone biosynthesis, and subsequently an increased production of styrylpyrone polyphenols. In parallel, the NO burst also resulted in S-nitrosylation of PAL, 4CL, and SPS, which compromised their enzymatic activities mediating a post-translational feedback mechanism that keeps NO-dependent transcriptional activation in check. Moreover, dysfunction of thioredoxin reductase (TrxR) further increased the formation of S-nitrosylated proteins, implicating the significance of the Trx system in maintaining a low level of protein-nitrosothiols. Three thioredoxin-like proteins (TrxLs) from I. obliquus show in vitro denitrosylation potential toward S-nitrosylated proteins via trans-denitrosylation or mixed disulfide intermediates. Thus, S-nitrosylation triggered by the NO burst limits over production of fungal styrylpyrone polyphenols, and denitrosylation by TrxLs that act in concert with TrxR play a key role in maintaining redox balance and orchestrating catalytic activities of the enzymes engaged in styrylpyrone synthetic metabolism. PMID:27000840

  4. Induction and analysis of rice lesion mimic mutant

    International Nuclear Information System (INIS)

    A lesion mimic mutant of rice (Oryza sativa L.), named as cer1, was induced from a japonic rice variety Katy with 1.0% ethyl methane-sulfonate (EMS) treatment. Phenotype of mutant was comparatively characterized along with the original parent Katy. The height, the number of tillers, one-thousand-grain weight of mutant was significantly reduced than those of Katy. Genetic analysis indicated that the mutation is controlled by single recessive gene. Lesion mimic phenotype of LmmKaty was rapidly induced by virulent M. grisea isolates or by avirulent isolates only at high levels of inoculum. Autofluorescence (a sign of an active defense response) was visible under ultraviolet light 24 h after localized inoculation in the incompatible interaction whereas, autofluorescence was not evident in the compatible interaction. Autofluorescence was also observed in LmmKaty 20 h after pathogen inoculation, thus indicating that rapid cell death is a mechanism of LmmKaty to restrict pathogen invasion. Rapid accumulation of defense related (DR) gene transcripts, phenylalanine ammonia lyase and β-glucanase, was observed beginning at 6 h and was obvious at 16 h and 24 h in an incompatible interaction. Rapid transcript accumulation of PR-1 and chitinase had occurred by 24 h after inoculation in an incompatible interaction. Accumulation of these transcripts was delayed in a compatible interaction. These results indicate that host active defense responses occur 24 h after pathogen inoculation and that LmmKaty exhibits enhanced resistance to M. grisea. (author)

  5. Response of Antioxidant Substances and Enzymes Activities as a Defense Mechanism Against Root-Knot Nematode Infection

    Directory of Open Access Journals (Sweden)

    Hossam Saad EL-BELTAGI

    2012-05-01

    Full Text Available The organic amendments, composts (1, 2, 3, neem and poultry as well as inorganic fertilizers (NPK compound and commercial, Athree® and the nematicide nemacur 10 G applied singly were effective in reducing M. incognita number of galls, nematode reproductionand fecundity. The effectiveness seemed to be material origin dependent. Neem, compost 1, 3 (5 g/pot gave the best results. Yet, achievedresults were less than those of nemacur 10% G. The antioxidant substances content and enzymes activities due to nematode infectionand application of organic and inorganic fertilizers pointed to significant increase of lipid peroxidation and hydrogen peroxide as aresult of nematode infection and nemacur treatment. While all organic and inorganic fertilizers reduced such materials with significantdifferences among treatments. Likewise, nematode infection resulted in slight but significant increase in glutathione and ascorbic acidin tomato shoots and roots. All treatments increased antioxidant substances comparing to healthy and infected plants. Glutathione-Stransferaseactivity highly increased in infected roots but the lowest activities were achieved by organic fertilizers. Nematode infectionand nemacur treatment increased slightly phenylalaine ammonia lyase activity but enormous increase was observed in shoots and rootsof treated plants with organic fertilizers followed by NPK treatments.

  6. Synthesis and regulation of chlorogenic acid in potato: Rerouting phenylpropanoid flux in HQT-silenced lines.

    Science.gov (United States)

    Payyavula, Raja S; Shakya, Roshani; Sengoda, Venkatesan G; Munyaneza, Joseph E; Swamy, Prashant; Navarre, Duroy A

    2015-05-01

    Chlorogenic acid (CGA) is the major phenolic sink in potato tubers and can constitute over 90% of total phenylpropanoids. The regulation of CGA biosynthesis in potato and the role of the CGA biosynthetic gene hydroxycinnamoyl CoA:quinate hydroxycinnamoyl transferase (HQT) was characterized. A sucrose induced accumulation of CGA correlated with the increased expression of phenylalanine ammonia-lyase (PAL) rather than HQT. Transient expression of the potato MYB transcription factor StAN1 (anthocyanin 1) in tobacco increased CGA. RNAi suppression of HQT resulted in over a 90% reduction in CGA and resulted in early flowering. The reduction in total phenolics and antioxidant capacity was less than the reduction in CGA, suggesting flux was rerouted into other phenylpropanoids. Network analysis showed distinct patterns in different organs, with anthocyanins and phenolic acids showing negative correlations in leaves and flowers and positive in tubers. Some flavonols increased in flowers, but not in leaves or tubers. Anthocyanins increased in flowers and showed a trend to increase in leaves, but not tubers. HQT suppression increased biosynthesis of caffeoyl polyamines, some of which are not previously reported in potato. Decreased PAL expression and enzyme activity was observed in HQT suppressed lines, suggesting the existence of a regulatory loop between CGA and PAL. Electrophysiology detected no effect of CGA suppression on potato psyllid feeding. Collectively, this research showed that CGA in potatoes is synthesized through HQT and HQT suppression altered phenotype and redirected phenylpropanoid flux. PMID:25421386

  7. Linoleic acid-induced expression of defense genes and enzymes in tobacco.

    Science.gov (United States)

    Sumayo, Marilyn S; Kwon, Duck-Kee; Ghim, Sa-Youl

    2014-11-15

    Linoleic acid (LA) is a naturally occurring fatty acid (FA) found to elicit induced systemic resistance (ISR) of tobacco against the bacterial soft rot pathogen, Pectobacterium carotovorum subsp. carotovorum (PCC). In this study, we examined effects of six doses of exogenous LA on the induction of defense genes and enzymes. The optimum ISR activity was observed in plants treated with 0.1mM LA where the effect of LA on membrane permeability was minimal. The application of LA as a root drench enhanced the activity of defense enzymes such as phenylalanine ammonia-lyase (PAL), peroxidase (POD), and polyphenol oxidase (PPO) and induced the expression of β-glucuronidase (GUS). PAL and POD activities were increased in a concentration dependent manner while the maximum PPO activity was observed after treatment with 0.01mM LA. An RT-PCR analysis of the defense-related genes, Coi1, NPR1, PR-1a and PR-1b, of tobacco plants treated with 0.1mM LA revealed an association of LA with elicitation of ISR in tobacco. PMID:25238656

  8. Anion channels and the stimulation of anthocyanin accumulation by blue light in Arabidopsis seedlings

    Science.gov (United States)

    Noh, B.; Spalding, E. P.; Evans, M. H. (Principal Investigator)

    1998-01-01

    Activation of anion channels by blue light begins within seconds of irradiation in seedlings and is related to the ensuing growth inhibition. 5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) is a potent, selective, and reversible blocker of these anion channels in Arabidopsis thaliana. Here we show that 20 microM NPPB blocked 72% of the blue-light-induced accumulation of anthocyanin pigments in seedlings. Feeding biosynthetic intermediates to wild-type and tt5 seedlings provided evidence that NPPB prevented blue light from up-regulating one or more steps between and including phenylalanine ammonia lyase and chalcone isomerase. NPPB was found to have no significant effect on the blue-light-induced increase in transcript levels of PAL1, CHS, CHI, or DFR, which are genes that encode anthocyanin-biosynthetic enzymes. Immunoblots revealed that NPPB also did not inhibit the accumulation of the chalcone synthase, chalcone isomerase, or flavanone-3-hydroxylase proteins. This is in contrast to the reduced anthocyanin accumulation displayed by a mutant lacking the HY4 blue-light receptor, as hy4 displayed reduced expression of the above enzymes. Taken together, the data indicate that blue light acting through HY4 leads to an increase in the amount of biosynthetic enzymes but blue light must also act through a separate, anion-channel-dependent system to create a fully functional biosynthetic pathway.

  9. Coronatine Induces an Accumulation of Anthocyanin and Starch in Purple-fleshed Sweetpotato (Ipomoea batatas Lam.)

    Institute of Scientific and Technical Information of China (English)

    Baoqing WANG; Beitao XIE; Haiyan ZHANG; Liming ZHANG; Qingmei WANG

    2013-01-01

    [Objective] The objective of this research was to examine the effects of COR on anthocyanin and starch content in storage roots of two PFS genotypes, and to explore the relationships between anthocyanin synthesis and starch accumula-tion. [Method] A field experiment was carried out to determine the changes in yield components, yield, contents of anthocyanin and starch, activities of phenylalanine ammonia-lyase (PAL) and adenosine 5-diphosphate glucose pyrophosphorylase (AG-Pase) in two genotypes of PFS (Ipomoea batatas L., var. ‘Ayamurasaki’ and‘Jishu18’). [Result] The application of COR significantly increased starch and antho-cyanin content in storage roots of Jishu18 across developmental stages by inducing the activities of PAL and AGPase, and final y enhanced yield by promoting fresh weight of storage roots. Ayamurasaki was insensitive to treatment with COR al-though its PAL activity temporal y increased. The starch and anthocyanin content of Aya, and the anthocyanin content of Jishu18 increased progressively across devel-opmental stages with or without COR application, but the starch content of Jishu18 increased initial y, then decreased before increasing again without application of COR. Treatment with COR reduced downward trend of starch accumulation in Jishu18. Thus, the effect of COR on accumulation of anthocyanin and starch in storage roots of PFS differs according to genotypes. [Conclusion] The application of 0.05 μmol/L COR may increase starch and anthocyanin content in PFS genotypes with lower starch and anthocyanin content in storage roots.

  10. Phyllosticta musarum Infection-Induced Defences Suppress Anthracnose Disease Caused by Colletotrichum musae in Banana Fruits cv ‘Embul’

    Directory of Open Access Journals (Sweden)

    C. L. Abayasekara

    2013-03-01

    Full Text Available Anthracnose development by Colletotrichum musae was observed to be significantly less in the fruits of the banana cultivar ‘Embul’ (Mysore, AAB infected with Phyllosticta musarum than in fruits without such infections. Anthracnose disease originates from quiescent C. musae infections in the immature fruit. P. musarum incites minute, scattered spots, referred to as freckles, in the superficial tissues of immature banana peel which do not expand during maturation or ripening. P. musarum does not appear to have a direct suppressive effect on C. musae as conidia of C. musae germinate on both freckled and non-freckled fruit forming quiescent infections. Our investigations have shown that P. musarum infection induced several defence responses in fruit including the accumulation of five phytoalexins, upregulation of chitinase and β-1,3-glucanase, phenylalanine ammonia lyase (PAL activity and cell wall lignification. ¹H and ¹³C NMR spectral data of one purified phytoalexin compared closely with 4′-hydroxyanigorufone. Some of the P. musarum-induced defences that retained during ripening, restrict C. musae development at the ripe stage. This paper examines the potential of P. musarum-induced defences, in the control of anthracnose, the most destructive postharvest disease in banana.

  11. Induction of resveratrol biosynthesis in skins of three grape cultivars by ultraviolet irradiation

    International Nuclear Information System (INIS)

    Resveratrol production and expression of the genes related to resveratrol biosynthesis were investigated in the skins of three Vitis vinifera cultivars Chardonnay, Koshu and an American hybrid grape, Muscat Bailey A (Bailey x Muscat Hamburg). Resveratrol concentration in the skins of all the grapes increased significantly when exposed to ultraviolet (UV-C, 254 nm) irradiation. The UV-induced resveratrol concentration in the grape skins was lower after veraison (onset of ripening) than before it. The maximum concentration of the UV-induced resveratrol in 'Muscat Bailey A' was higher than those in the other two cultivars. The relative mRNA expression levels of stilebene synthase (STS), phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) genes in grape skins 8 hr after UV irradiation were determined by quantitative reverse transcription-polymerase chain reaction (RT-PCR). The results revealed that STS- and PAL-mRNA expressions were significantly increased by UV irradiation. STS-mRNA expressions in 'Muscat Bailey A' were higher than those in 'Chardonnay' throughout berry development. The UV-induced CHS-mRNA expression in the grape skins decreased before veraison and subsequently increased. (author)

  12. Seaweed Polysaccharides and Derived Oligosaccharides Stimulate Defense Responses and Protection Against Pathogens in Plants

    Directory of Open Access Journals (Sweden)

    Alejandra Moenne

    2011-11-01

    Full Text Available Plants interact with the environment by sensing “non-self” molecules called elicitors derived from pathogens or other sources. These molecules bind to specific receptors located in the plasma membrane and trigger defense responses leading to protection against pathogens. In particular, it has been shown that cell wall and storage polysaccharides from green, brown and red seaweeds (marine macroalgae corresponding to ulvans, alginates, fucans, laminarin and carrageenans can trigger defense responses in plants enhancing protection against pathogens. In addition, oligosaccharides obtained by depolymerization of seaweed polysaccharides also induce protection against viral, fungal and bacterial infections in plants. In particular, most seaweed polysaccharides and derived oligosaccharides trigger an initial oxidative burst at local level and the activation of salicylic (SA, jasmonic acid (JA and/or ethylene signaling pathways at systemic level. The activation of these signaling pathways leads to an increased expression of genes encoding: (i Pathogenesis-Related (PR proteins with antifungal and antibacterial activities; (ii defense enzymes such as pheylalanine ammonia lyase (PAL and lipoxygenase (LOX which determine accumulation of phenylpropanoid compounds (PPCs and oxylipins with antiviral, antifugal and antibacterial activities and iii enzymes involved in synthesis of terpenes, terpenoids and/or alkaloids having antimicrobial activities. Thus, seaweed polysaccharides and their derived oligosaccharides induced the accumulation of proteins and compounds with antimicrobial activities that determine, at least in part, the enhanced protection against pathogens in plants.

  13. Phenolic metabolites in carnivorous plants: Inter-specific comparison and physiological studies.

    Science.gov (United States)

    Kováčik, Jozef; Klejdus, Bořivoj; Repčáková, Klára

    2012-03-01

    Despite intensive phytochemical research, data related to the accumulation of phenols in carnivorous plants include mainly qualitative reports. We have quantified phenolic metabolites in three species: Drosera capensis, Dionaea muscipula and Nepenthes anamensis in the "leaf" (assimilatory part) and the "trap" (digestive part). For comparison, commercial green tea was analysed. Phenylalanine ammonia-lyase (PAL) activities in Dionaea and Nepenthes were higher in the trap than in the leaf while the opposite was found in Drosera. Soluble phenols and majority of phenolic acids were mainly accumulated in the trap among species. Flavonoids were abundant in Drosera and Dionaea traps but not in Nepenthes. Phenolic acids were preferentially accumulated in a glycosidically-bound form and gallic acid was the main metabolite. Green tea contained more soluble phenols and phenolic acids but less quercetin. In vitro experiments with Drosera spathulata revealed that nitrogen deficiency enhances PAL activity, accumulation of phenols and sugars while PAL inhibitor (2-aminoindane-2-phosphonic acid) depleted phenols and some amino acids (but free phenylalanine and sugars were elevated). Possible explanations in physiological, biochemical and ecological context are discussed. PMID:22305064

  14. Nitric oxide mediates isoflavone accumulation and the antioxidant system enhancement in soybean sprouts.

    Science.gov (United States)

    Jiao, Caifeng; Yang, Runqiang; Zhou, Yulin; Gu, Zhenxin

    2016-08-01

    In this study, we investigated the relationships between endogenous NO signal transduction pathways, the antioxidant system and isoflavone accumulation induced by UV-B radiation in soybean sprouts. Results showed that UV-B-triggered NO generation induced isoflavone accumulation by up-regulating the activity and gene expression of key enzymes (phenylalanine ammonia lyase, PAL; chalcone isomerase, CHI; chalcone synthase, CHS; isoflavone synthase, IFS) that participate in isoflavone biosynthesis and enhanced the antioxidant system by regulating levels of antioxidants (glutathione reductase, GR; glutathione S-transferase, GST; ascorbate peroxidase, APX; glutathione GSH; ascorbic acid, ASC), antioxidant enzyme activities (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT) and their gene expression. These effects were inhibited by the addition of a specific NO-scavenger, carboxy-PTIO (cPTIO). The inhibition was reversed through application of the exogenous NO donor, SNP. Overall, NO is an essential signaling molecule, mediating UV-B-induced isoflavone accumulation and the antioxidant system enhancement in soybean sprouts. PMID:26988515

  15. DL-β-aminobutyric acid-induced resistance in soybean against Aphis glycines Matsumura (Hemiptera: Aphididae.

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    Yunpeng Zhong

    Full Text Available Priming can improve plant innate capability to deal with the stresses caused by both biotic and abiotic factors. In this study, the effect of DL-β-amino-n-butyric acid (BABA against Aphis glycines Matsumura, the soybean aphid (SA was evaluated. We found that 25 mM BABA as a root drench had minimal adverse impact on plant growth and also efficiently protected soybean from SA infestation. In both choice and non-choice tests, SA number was significantly decreased to a low level in soybean seedlings drenched with 25 mM BABA compared to the control counterparts. BABA treatment resulted in a significant increase in the activities of several defense enzymes, such as phenylalanine ammonia-lyase (PAL, peroxidase (POX, polyphenol oxidase (PPO, chitinase (CHI, and β-1, 3-glucanase (GLU in soybean seedlings attacked by aphid. Meanwhile, the induction of 15 defense-related genes by aphid, such as AOS, CHS, MMP2, NPR1-1, NPR1-2, and PR genes, were significantly augmented in BABA-treated soybean seedlings. Our study suggest that BABA application is a promising way to enhance soybean resistance against SA.

  16. Accumulation of Kaempferitrin and Expression of Phenyl-Propanoid Biosynthetic Genes in Kenaf (Hibiscus cannabinus

    Directory of Open Access Journals (Sweden)

    Shicheng Zhao

    2014-10-01

    Full Text Available Kenaf (Hibiscus cannabinus is cultivated worldwide for its fiber; however, the medicinal properties of this plant are currently attracting increasing attention. In this study, we investigated the expression levels of genes involved in the biosynthesis of kaempferitrin, a compound with many biological functions, in different kenaf organs. We found that phenylalanine ammonia lyase (HcPAL was more highly expressed in stems than in other organs. Expression levels of cinnamate 4-hydroxylase (HcC4H and 4-coumarate-CoA ligase (Hc4CL were highest in mature leaves, followed by stems and young leaves, and lowest in roots and mature flowers. The expression of chalcone synthase (HcCHS, chalcone isomerase (HcCHI, and flavone 3-hydroxylase (HcF3H was highest in young flowers, whereas that of flavone synthase (HcFLS was highest in leaves. An analysis of kaempferitrin accumulation in the different organs of kenaf revealed that the accumulation of this compound was considerably higher (>10-fold in leaves than in other organs. On the basis of a comparison of kaempferitrin contents with the expression levels of different genes in different organs, we speculate that HcFLS plays an important regulatory role in the kaempferitrin biosynthetic pathway in kenaf.

  17. Efeects of pretreated ozone and modified atmosphere packaging on the quality of fresh-cut green asparagus

    Directory of Open Access Journals (Sweden)

    Qirui Lu

    2006-06-01

    Full Text Available The changes in lignifying, antioxidant enzyme activities and cell wall composition of fresh-cut green asparagus (Asparagus officinalis L., pretreated in 1 mg l-1 aqueous ozone and subsequently packaged in modified atmosphere (MAP, were investigated during storage at 3°C for 25 days. The enzyme activities in fresh-cut asparagus including phenylalanine ammonia lyase (PAL, superoxide dismutase (SOD, ascorbate peroxidase (APX, glutathione reductase (GR were inhibited by aqueous ozone treatment and subsequent modified atmosphere packaging. Changes in lignin, cellulose and hemicellulose contents were also monitored during storage. Similarly, the increase of the cell wall composition elements under the aqueous ozone treatment and/or MAP were significantly reduced (P<0.05. The possible mechanisms in which changes in enzymatic activities and cell wall composition occurred were discussed. Compared to the control group, enzyme activities in MAP and/or group remained high, which means that asparagus in the two latter groups remained a high-ability scavenger of free radicals. It was found that as a result of treatment in O3 and/or MAP, PAL activity presented a peak at day 10 of storage, but its activities were significantly lower than in the control group. The increase in lignin levels during storage is attributed to the toughening which occurs in asparagus a few days after harvest.

  18. Metabolic Response of Strawberry (Fragaria x ananassa) Leaves Exposed to the Angular Leaf Spot Bacterium (Xanthomonas fragariae).

    Science.gov (United States)

    Kim, Min-Sun; Jin, Jong Sung; Kwak, Youn-Sig; Hwang, Geum-Sook

    2016-03-01

    Plants have evolved various defense mechanisms against biotic stress. The most common mechanism involves the production of metabolites that act as defense compounds. Bacterial angular leaf spot disease (Xanthomonas fragariae) of the strawberry (Fragaria x ananassa) has become increasingly destructive to strawberry leaves and plant production. In this study, we examined metabolic changes associated with the establishment of long-term bacterial disease stress using UPLC-QTOF mass spectrometry. Infected leaves showed decreased levels of gallic acid derivatives and ellagitannins, which are related to the plant defense system. The levels of phenylalanine, tryptophan, and salicylic acid as precursors of aromatic secondary metabolites were increased in inoculated leaves, whereas levels of coumaric acid, quinic acid, and flavonoids were decreased in infected plants, which are involved in the phenylpropanoid pathway. In addition, phenylalanine ammonia-lyase (PAL) activity, a key enzyme in the phenylpropanoid pathway, was decreased following infection. These results suggest that long-term bacterial disease stress may lead to down-regulation of select molecules of the phenylpropanoid metabolic pathway in strawberry leaves. This approach could be applied to explore the metabolic pathway associated with plant protection/breeding in strawberry leaves. PMID:26890088

  19. Isotopologue profiling of the listerial N-metabolism.

    Science.gov (United States)

    Kutzner, Erika; Kern, Tanja; Felsl, Angela; Eisenreich, Wolfgang; Fuchs, Thilo M

    2016-04-01

    The nitrogen (N-) sources and the relative contribution of a nitrogenous nutrient to the N-pool of the gram-positive pathogen Listeria monocytogenes are largely unknown. Therefore, (15) N-isotopologue profiling was established to study the N-metabolism of L. monocytogenes. The pathogen was grown in a defined minimal medium supplemented with potential (15) N-labeled nutrients. The bacteria were harvested and hydrolysed under acidic conditions, and the resulting amino acids were analysed by GC-MS, revealing (15) N-enrichments and isotopomeric compositions of amino acids. The differential (15) N-profiles showed the substantial and simultaneous usage of ammonium, glutamine, methionine, and, to a lower extent, the branched-chain amino acids valine, leucine, and isoleucine for anabolic purposes, with a significant preference for ammonium. In contrast, arginine, histidine and cysteine were directly incorporated into proteins. L. monocytogenes is able to replace glutamine with ethanolamine or glucosamine as amino donors for feeding the core N-metabolism. Perturbations of N-fluxes caused by gene deletions demonstrate the involvement of ethanolamine ammonia lyase, and suggest a role of the regulator GlnK of L. monocytogenes distinct from that of Escherichia coli. The metabolism of nitrogenous nutrients reflects the high flexibility of this pathogenic bacterium in exploiting N-sources that could also be relevant for its proliferation during infection. PMID:26699934

  20. A Bio-Inspired Catalyst for CO2 Reduction

    Science.gov (United States)

    Bovell, Adonis; Warncke, Kurt

    2009-11-01

    Efficient storage of solar energy is critical for the next generation of solar energy conversion systems. Herein is described a catalytic module, using the robust TIM barrel fold of the EutB subunit of ethanolamine-ammonia lyase (EAL), for high specificity recognition and light-driven reduction of CO2 to energy rich biofuels. EAL catalyzes the deamination of ethanolamine via a free radical mechanism, by using an adenosylcobalamin (AdoCbl) cofactor. Our aim is to use the reducing power of the cobalt(I) form of the cofactor to drive the reduction of CO2. Molecular biology techniques have been used to generate histidine-tagged EutB subunits of EAL for high throughput protein purification. The binding of cobalamins to EutB was probed by using tryptophan fluorescence quenching. The Hill constant (KH) and coefficient (nH) for AdoCbl-EutB binding were determined as 33 μM and 1.3, respectively. The results show that cob(III)alamin binds to isolated EutB, and suggest that Co(II) and Co(I) states will also bind. Rational active site modifications of EutB will be made to facilitate specific CO2-Co(I) binding and to introduce a proton delivery network. The results will give insight into the challenging task of rational enzyme design.

  1. Developing a Biologically-Inspired Molecular Solar Energy Conversion Device: Reaction of Solution and Protein-Bound Cobalamins with Carbon Dioxide and Halo-Organic Compounds

    Science.gov (United States)

    Robertson, Wesley D.; Ennist, Nathan M.; Warncke, Kurt

    2009-11-01

    Our aim is to design and construct protein-based artificial photosynthetic systems that reduce carbon dioxide (CO2) and toxic halo-organic compounds within the robust and adaptable (βα)8 TIM-barrel protein structure. The EutB subunit of the adenosylcobalamin-dependent enzyme, ethanolamine ammonia-lyase (EAL), from Salmonella typhimurium, was selected as the protein template. The Co^I forms of the native cobalamin (Cbl) cofactor and a derivative, cobinamide (Cbi), possess relatively low redox potentials that are commensurate with reduction of CO2 and halo-organic compounds. Titanium^III citrate and pulsed laser-excited 5'-deazariboflavin (5'-DRF) were used to reduce Cbl or Cbi. UV/visible absorption spectroscopy was used to monitor the reaction kinetics of reduced Cbl and Cbi with CO2 and halo-organics, and 13C-NMR was used for product analysis. The results provide fundamental information for development of an organocobalt-based protein-catalytic device for stable fuels generation and toxic chemical remediation.

  2. Radical Rearrangement Catalysis in an Enzyme at 190-207 K: Mechanistic Features Revealed by Substrate ^1H/^2H Isotope Effects

    Science.gov (United States)

    Zhu, Chen; Warncke, Kurt

    2009-11-01

    The decay kinetics of both the natural abundance and [1,1,2,2-^2H4]-aminoethanol generated Co^II-substrate radical pair catalytic intermediate in ethanolamine ammonia-lyase (EAL) from Salmonella typhimrium have been measured by using time-resolved, full-spectrum X-band continuous-wave electron paramagnetic resonance (EPR) spectroscopy in frozen aqueous solution from 190 to 207 K. The decay reaction proceeds through sequential radical covalent rearrangement and hydrogen atom transfer (HT) steps. In the temperature range from 190 to 207 K, the decay is biexponential, and the two phases correspond to distinct populations [1]. The ^1H/^2H isotope effects (IE) on the fast phase and slow phase are 1.3 and 0.8, respectively. These IE are not caused by a primary kinetic IE. Therefore, HT is rapid, relative to rearrangement. We propose that the fast phase is rate-determined by the rearrangement step, and that the slow phase is rate-determined by a step after rearrangement that is associated with protein guidance of the reactions. The results reveal microscopic features of the core reaction chemistry and protein dynamics participation in the reaction, which are not accessible at ambient temperatures.[4pt] [1] Zhu, C., Warncke, K. Biophys. J. 95, 5890 (2008). Supported by grant DK54514 from NIDDK/NIH.

  3. Bacillus cereus AR156-induced resistance to Colletotrichum acutatum is associated with priming of defense responses in loquat fruit.

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    Xiaoli Wang

    Full Text Available The effectiveness of a biocontrol agent Bacillus cereus AR156 for control of anthracnose rot caused by Colletotrichum acutatum in harvested loquat fruit and the possible mechanisms of its action have been investigated. Treatment of fruit with B. cereus AR156 resulted in lower disease incidence and smaller lesion diameters compared with that of untreated fruit. The treatment enhanced activities of defense-related enzymes including chitinase, β-1, 3-glucanase, phenylalanine ammonia-lyase, peroxidase and polyphenoloxidase, and promoted accumulation of H2O2. Total phenolic content and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity were also increased by treatment. Transcripts of three defense-related genes were enhanced only in fruit undergoing both B. cereus AR156 treatment and C. acutatum inoculation compared with those receiving either intervention alone. These results suggest that the disease resistance against C. acutatum in loquat fruit is enhanced by B. cereus AR156 and that the induced resistance is associated with induction and priming of defense responses in the fruit.

  4. Bacillus cereus AR156-induced resistance to Colletotrichum acutatum is associated with priming of defense responses in loquat fruit.

    Science.gov (United States)

    Wang, Xiaoli; Wang, Lei; Wang, Jing; Jin, Peng; Liu, Hongxia; Zheng, Yonghua

    2014-01-01

    The effectiveness of a biocontrol agent Bacillus cereus AR156 for control of anthracnose rot caused by Colletotrichum acutatum in harvested loquat fruit and the possible mechanisms of its action have been investigated. Treatment of fruit with B. cereus AR156 resulted in lower disease incidence and smaller lesion diameters compared with that of untreated fruit. The treatment enhanced activities of defense-related enzymes including chitinase, β-1, 3-glucanase, phenylalanine ammonia-lyase, peroxidase and polyphenoloxidase, and promoted accumulation of H2O2. Total phenolic content and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity were also increased by treatment. Transcripts of three defense-related genes were enhanced only in fruit undergoing both B. cereus AR156 treatment and C. acutatum inoculation compared with those receiving either intervention alone. These results suggest that the disease resistance against C. acutatum in loquat fruit is enhanced by B. cereus AR156 and that the induced resistance is associated with induction and priming of defense responses in the fruit. PMID:25386680

  5. A role for molecular compression in the post-translational formation of the Green Fluorescent Protein chromophore

    International Nuclear Information System (INIS)

    Graphical abstract: Using molecular dynamics simulations, we estimate the contribution of the Green Fluorescent Protein beta-barrel in promoting backbone cyclization, i.e. a crucial step in chromophore formation. - Abstract: Spontaneous chromophore formation is probably the key feature for the remarkable success of GFPs (Green Fluorescent Proteins) and related proteins in fluorescence microscopy. Though a quantitative analysis of the involved energetics still remains elusive, substantial progress has been made in identifying the steps of chromophore biosynthesis and the contribution of individual residues and surrounding protein matrix. The latter clearly enforces a peculiar configuration of the pre-cyclized chromophore-forming tripeptide. However, it is debated whether a mechanical compression is also at play in triggering backbone cyclization. Here, by molecular dynamics and potential of mean force calculations, we estimate the contribution of the protein scaffold in promoting the proximity of reacting atoms- and hence backbone cyclization - by a sort of compression mechanism. Comparing several mutants we highlight the role of some surrounding residues. Finally, we analyze the case of HAL (Histidine Ammonia-Lyase) active site, which undergoes an analogous cyclization reaction.

  6. Elicitor-Induced Defense Responses in Solanum lycopersicum against Ralstonia solanacearum

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    Sudhamoy Mandal

    2013-01-01

    Full Text Available We investigated on important parameters of induced resistance in hydroponic tomato (Solanum lycopersicum against Ralstonia solanacearum using the elicitors chitosan (CHT, salicylic acid (SA, and jasmonic acid (JA. The increase in total phenolic content of roots by the elicitors was significantly higher than control. Most pronounced increase in lignin synthesis was triggered by SA followed by CHT. At 24 h post-elicitation (hpe, the activity of phenylalanine ammonia lyase was 4.5 times higher than control elicited by CHT. The peroxidase activity was about 86 nkat/mg protein at 24 hpe in case of SA and 78 nkat/mg protein in case of CHT. The activity of polyphenol oxidase increased several folds by the elicitors. Cinnamyl alcohol dehydrogenase activity increased to the maximum at 48 hpe under the influence of CHT. The results indicate that the elicitors SA and CHT induced effective defense responses in tomato plants against R. solanacearum. This was evident from reduced vascular browning and wilting symptoms of tomato plants treated with SA and CHT and challenged subsequently with R. solanacearum. This reduced disease incidence in tomato by SA and CHT may be a result of cell wall strengthening through deposition of lignin and the coincident induction of defense enzymes.

  7. Rhizobacteria induces resistance against Fusarium wilt of tomato by increasing the activity of defense enzymes

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    Hélvio Gledson Maciel Ferraz

    2014-09-01

    Full Text Available Fusarium wilt, caused by Fusarium oxysporum f.sp. lycopersici (Fol, is one of the most important diseases that affect tomato yield worldwide. This study investigated the potential of three antagonists, Streptomyces setonii (UFV 618, Bacillus cereus (UFV 592 and Serratia marcescens (UFV 252, and as positive control the hormone jasmonic acid (JA, to reduce Fusarium wilt symptoms and to potentiate the defense enzymes in the stem tissues of tomato plants infected by Fol. The seeds were microbiolized with each antagonist, and the soil was also drenched with them. The plants were sprayed with JA 48 h before Fol inoculation. The area under the Fusarium wilt index progress curve was reduced by 54, 48, 47 and 45% for the UFV 618, JA, UFV 592 and UFV 252 treatments, respectively. The three antagonists, and even the JA spray, efficiently reduced the Fusarium wilt symptoms on the tomato plant stems, which can be explained by the lower malondialdehyde concentration (an indication of oxidative damage to lipids in the plasma membranes and the greater activities of peroxidases, polyphenoloxidases, glucanases, chitinases, phenylalanine ammonia-lyases and lipoxygenases, which are commonly involved in host resistance against fungal diseases. These results present a novel alternative that can be used in the integrated management of Fusarium wilt on tomatoes.

  8. Immobilization of cells for use as biocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Vojtisek, V.; Jirku, V.; Krumphanzl, V.; Culik, K.

    1983-07-21

    Bacterial cells and cells of higher organisms are immobilized on polymers, either as whole cells, cell fragments, or subcellular components. This immobilization is used for stabilization of their various enzymic activities, which are of commercial interest, e.g. for the enzymes themselves, for alkaloid production, for hormone transformations, or for various fermentations. Thus, Sedipur CL-930 was polymerized in the presence of glutaraldehyde and the polymer was incubated with Alcaligenes metalcaligenes cells for immobilization. The nonimmobilized cells contained an aspartate ammonia-lyase activity of 550 mumol L-aspartate converted/min/g, and the immobilized cells contained an activity of 420 or 500 mumol aspartate/min/g when the polymer used was made with 2 different ratios of Sedipur to glutaraldehyde. The immobilized cell product had the form of defined platelets (lamellae) with a diameter of 100-600 mum, depending on the Sedipur/glutaraldehyde ratio. In other procedures, cells were permeabilized with tensides and/or organic solvents after the immobilization. Other cells immobilized included yeast, fungi, and plant cells. The activities which were examined included glycolytic enzymes, penicillin acylase, L-asparagine amidohydrolase and production of alkaloids and phytosterols from Solanum aviculare.

  9. Chemical products induce resistance to Xanthomonas perforans in tomato

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    Adriana Terumi Itako

    2015-09-01

    Full Text Available The bacterial spot of tomato, caused by Xanthomonas spp., is a very important disease, especially in the hot and humid periods of the year. The chemical control of the disease has not been very effective for a number of reasons. This study aimed to evaluate, under greenhouse conditions, the efficacy of leaf-spraying chemicals (acibenzolar-S-methyl (ASM (0.025 g.L−1, fluazinam (0.25 g.L−1, pyraclostrobin (0.08 g.L−1, pyraclostrobin + methiran (0.02 g.L−1 + 2.2 g.L−1, copper oxychloride (1.50 g.L−1, mancozeb + copper oxychloride (0.88 g.L−1 + 0.60 g.L−1, and oxytetracycline (0.40 g.L−1 on control of bacterial spot. Tomatoes Santa Clara and Gisele cultivars were pulverized 3 days before inoculation with Xanthomonas perforans. The production of enzymes associated with resistance induction (peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, and protease was quantified from leaf samples collected 24 hours before and 24 hours after chemical spraying and at 1, 2, 4, 6, and 8 days after bacterial inoculation. All products tested controlled bacterial spot, but only ASM, pyraclostrobin, and pyraclostrobin + metiram increased the production of peroxidase in the leaves of the two tomato cultivars, and increased the production of polyphenol oxidase and β-1,3-glucanase in the Santa Clara cultivar.

  10. Water stress responses of tomato mutants impaired in hormone biosynthesis reveal abscisic acid, jasmonic acid and salicylic acid interactions

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    Valeria eMuñoz

    2015-11-01

    Full Text Available To investigate the putative crosstalk between JA and ABA in Solanum lycopersicum plants in response to drought, suppressor of prosystemin-mediated responses2 (spr2, JA-deficient and flacca (flc, ABA-deficient mutants together with the naphthalene/salicylate hydroxylase (NahG transgenic (SA-deficient line were used. Hormone profiling and gene expression of key enzymes in ABA, JA and SA biosynthesis were analyzed during early stages of drought. ABA accumulation was comparable in spr2 and wild type (WT plants whereas expression of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1 and NCED2 was different, implying a compensation mechanism between NCED genes and an organ-specific regulation of NCED1 expression. JA levels and 12-oxo-phytodienoic acid reductase 3 (OPR3 expression in flc plants suggest that ABA regulates the induction of the OPR3 gene in roots. By contrast, ABA treatment to flc plants leads to a reduction of JA and SA contents. Furthermore, different pattern of SA accumulation (and expression of isochorismate synthase and phenylalanine ammonia lyase 1 was observed between WT seedlings and mutants, suggesting that SA plays an important role on the early response of tomato plants to drought and also that JA and ABA modulate its biosynthesis. Finally, hormone profiling in spr2 and NahG plants indicate a crosstalk between JA and SA that could enhance tolerance of tomato to water stress.

  11. Water Stress Responses of Tomato Mutants Impaired in Hormone Biosynthesis Reveal Abscisic Acid, Jasmonic Acid and Salicylic Acid Interactions.

    Science.gov (United States)

    Muñoz-Espinoza, Valeria A; López-Climent, María F; Casaretto, José A; Gómez-Cadenas, Aurelio

    2015-01-01

    To investigate the putative crosstalk between JA and ABA in Solanum lycopersicum plants in response to drought, suppressor of prosystemin-mediated responses2 (spr2, JA-deficient) and flacca (flc, ABA-deficient) mutants together with the naphthalene/salicylate hydroxylase (NahG) transgenic (SA-deficient) line were used. Hormone profiling and gene expression of key enzymes in ABA, JA and SA biosynthesis were analyzed during early stages of drought. ABA accumulation was comparable in spr2 and wild type (WT) plants whereas expression of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1) and NCED2 was different, implying a compensation mechanism between NCED genes and an organ-specific regulation of NCED1 expression. JA levels and 12-oxo-phytodienoic acid reductase 3 (OPR3) expression in flc plants suggest that ABA regulates the induction of the OPR3 gene in roots. By contrast, ABA treatment to flc plants leads to a reduction of JA and SA contents. Furthermore, different pattern of SA accumulation (and expression of isochorismate synthase and phenylalanine ammonia lyase 1) was observed between WT seedlings and mutants, suggesting that SA plays an important role on the early response of tomato plants to drought and also that JA and ABA modulate its biosynthesis. Finally, hormone profiling in spr2 and NahG plants indicate a crosstalk between JA and SA that could enhance tolerance of tomato to water stress. PMID:26635826

  12. Enhanced extracellular production of trans-resveratrol in Vitis vinifera suspension cultured cells by using cyclodextrins and coronatine.

    Science.gov (United States)

    Almagro, Lorena; Belchí-Navarro, Sarai; Martínez-Márquez, Ascensión; Bru, Roque; Pedreño, María A

    2015-12-01

    In the present work the effect of cyclodextrin and coronatine on both trans-resveratrol production and the expression of stilbene biosynthetic genes in Vitis vinifera L. cv Monastrell suspension cultured cells were evaluated. The results showed the maximum level of trans-resveratrol produced by cells and secreted to the culture medium with 50 mM cyclodextrins and 1 μM coronatine. Since the levels of trans-resveratrol produced in the combined treatment were higher than the sum of the individual treatments, a synergistic effect between both elicitors was assumed. In addition, all the analysed genes were induced by cyclodextrins and/or coronatine. The expression of the phenylalanine ammonia lyase and stilbene synthase genes was greatly enhanced by coronatine although an increase in the amount of trans-resveratrol in the spent medium was not detected. Therefore, despite the fact that trans-resveratrol production is related with the expression of genes involved in the biosynthetic process, other factors may be involved, such as post-transcriptional and post-traductional regulation. The expression maximal levels of cinnamate 4-hydroxylase and 4-coumarate-CoA ligase genes were found with cyclodextrins alone or in combination with coronatine suggesting that the activity of these enzymes could be not only important for the formation of intermediates of trans-R biosynthesis but also for those intermediates involved in the biosynthesis of lignins and/or flavonoids. PMID:26529079

  13. Shoot inversion inhibition of stem elongation in Pharbitis nil: a possible role for ethylene-induced glycoprotein and lignin

    Science.gov (United States)

    Prasad, T. K.; Cline, M. G.

    1987-01-01

    Inversion of the upper shoot of Pharbitis nil results in the inhibition of elongation in the inverted stem. The objective of the present study was to determine how shoot inversion-induced gravity stress inhibited elongation and to elucidate the possible role of ethylene-induced glycoprotein and lignin in this process. Determinations of hydroxyproline, peroxidase, phenylalanine ammonia-lyase (PAL), phenol, and lignin content/activity were carried out by appropriate spectrophotometric methods. It was found that inversion and Ethrel treatments of upright shoots caused significant increases in hydroxyproline content, peroxidase, and PAL activity in 12 hours and in phenol and lignin contents in 24 hours. All of these increases except for that of cytoplasmic peroxidase activity were partially reversed by AgNO3, the ethylene action inhibitor. It is concluded that possible cross-linking associated with the accumulation of the ethylene-induced hydroxyproline-rich glycoprotein and lignin may be responsible for the later stages of cessation of elongation in the inverted Pharbitis shoot.

  14. Allyl isothiocyanate enhances shelf life of minimally processed shredded cabbage.

    Science.gov (United States)

    Banerjee, Aparajita; Penna, Suprasanna; Variyar, Prasad S

    2015-09-15

    The effect of allyl isothiocyanate (AITC), in combination with low temperature (10°C) storage on post harvest quality of minimally processed shredded cabbage was investigated. An optimum concentration of 0.05μL/mL AITC was found to be effective in maintaining the microbial and sensory quality of the product for a period of 12days. Inhibition of browning was shown to result from a down-regulation (1.4-fold) of phenylalanine ammonia lyase (PAL) gene expression and a consequent decrease in PAL enzyme activity and o-quinone content. In the untreated control samples, PAL activity increased following up-regulation in PAL gene expression that could be linearly correlated with enhanced o-quinone formation and browning. The efficacy of AITC in extending the shelf life of minimally processed shredded cabbage and its role in down-regulation of PAL gene expression resulting in browning inhibition in the product is reported here for the first time. PMID:25863635

  15. Silicon, acibenzolar-S-methyl and potassium phosphite in the control of brown spot in rice

    Directory of Open Access Journals (Sweden)

    Kelly Juliane Telles Nascimento

    2016-01-01

    Full Text Available ABSTRACT This study investigated the effects of silicon (Si, acibenzolar-S-methyl (ASM, and potassium phosphite (Phi on the potentiation of rice resistance to infection by Bipolaris oryzae. The treatments included the soil amended with Si (1.25 g of calcium silicate per kg of soil, spraying of plants with ASM (500 mg∙L–1, Phi (5 mL∙L–1, and distilled water (control 24 h before inoculation with B. oryzae. The treatments Si supply and the spraying of ASM and Phi were effective in reducing the area under brown spot progress curve and the number of lesions per cm2 of leaf. Polyphenoloxidases activity was higher for plants supplied with Si. On plants sprayed with ASM, the activities of polyphenoloxidases, phenylalanine ammonia-lyases, chitinases, and β-1,3-glucanases increased. The spraying of plants with Phi did not increase the activities of the studied defense enzymes. Taken together, the results of this study indicated that brown spot symptoms can be greatly reduced with the use of Si, ASM, and Phi.

  16. Inducers of resistance and silicon on the activity of defense enzymes in the soybean-Phakopsora pachyrhizi interaction

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    Maria Fernanda Antunes da Cruz

    2013-06-01

    Full Text Available This study aimed to determine the effect of jasmonic acid (JA, Acibenzolar-S-Methyl (ASM and calcium silicate (a source of soluble silicon, Si, on the potentiation of soybean resistance to Asian soybean rust (ASR. The ASR severity was significantly reduced on plants sprayed with ASM or supplied with Si in comparison to plants sprayed with JA or deionized water. For chitinases (CHI, significant differences in activity between non-inoculated and inoculated plants sprayed with deionized water or with ASM occurred at 72 hours after inoculation (hai, at 24 and 72 hai when sprayed with JA and at 141 hai when supplied with Si. For β-1,3-glucanases (GLU, significant differences in activity between non-inoculated and inoculated plants sprayed with deionized water occurred at 24, 48 and 141 hai, but not until 72 for plants sprayed with ASM. For phenylalanine ammonia-lyases (PAL, significant differences in activity between non-inoculated and inoculated plants occurred only for plants sprayed with ASM at 72 and 141 hai. In conclusion, the ASR symptoms can be mild on plants sprayed with ASM or supplied with Si and that this amelioration likely involved the defense enzymes.

  17. Methyl Jasmonate and Salicylic Acid Induced Oxidative Stress and Accumulation of Phenolics in Panax ginseng Bioreactor Root Suspension Cultures

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    Kee-Yoeup Paek

    2007-03-01

    Full Text Available To investigate the enzyme variations responsible for the synthesis of phenolics, 40 day-old adventitious roots of Panax ginseng were treated with 200 μM methyl jasmonate (MJ or salicylic acid (SA in a 5 L bioreactor suspension culture (working volume 4 L. Both treatments caused an increase in the carbonyl and hydrogen peroxide (H2O2 contents, although the levels were lower in SA treated roots. Total phenolic, flavonoid, ascorbic acid, non-protein thiol (NPSH and cysteine contents and 1,1-diphenyl-2-picrylhydrazyl (DPPH radical reducing activity were increased by MJ and SA. Fresh weight (FW and dry weight (DW decreased significantly after 9 days of exposure to SA and MJ. The highest total phenolics (62%, DPPH activity (40%, flavonoids (88%, ascorbic acid (55%, NPSH (33%, and cysteine (62% contents compared to control were obtained after 9 days in SA treated roots. The activities of glucose 6-phosphate dehydrogenase, phenylalanine ammonia lyase, substrate specific peroxidases (caffeic acid peroxidase, quercetin peroxidase and ferulic acid peroxidase were higher in MJ treated roots than the SA treated ones. Increased shikimate dehydrogenase, chlorogenic acid peroxidase and β-glucosidase activities and proline content were observed in SA treated roots than in MJ ones. Cinnamyl alcohol dehydrogenase activity remained unaffected by both MJ and SA. These results strongly indicate that MJ and SA induce the accumulation of phenolic compounds in ginseng root by altering the phenolic synthesis enzymes.

  18. Induced phenylpropanoid metabolism during suberization and lignification: a comparative analysis

    Science.gov (United States)

    Bernards, M. A.; Susag, L. M.; Bedgar, D. L.; Anterola, A. M.; Lewis, N. G.

    2000-01-01

    Induction of the biosynthesis of phenylpropanoids was monitored at the enzyme level through measurement of the temporal change in the activity of two marker enzymes of phenylpropanoid metabolism, phenylalanine ammonia-lyase, (PAL, E.C. 4.1.3.5) and 4-coumaryl-CoA ligase (4-CL, E.C. 6.2.1.12) and two marker enzymes for hydroxycinnamyl alcohol biosynthesis, cinnamoyl-CoA:NADP+ oxidoreductase (CCR, E.C. 1.2.1.44) and cinnamyl alcohol dehydrogenase (CAD, E.C. 1.1.1.195) in both suberizing potato (Solanum tuberosum) tubers and lignifying loblolly pine (Pinus taeda) cell cultures. While measurable activities of PAL, 4-CL and CAD increased upon initiation of suberization in potato tubers, that of CCR did not. By contrast, all four enzymes were induced upon initiation of lignification in pine cell cultures. The lack of CCR induction in potato by wound treatment is consistent with the channelling of hydroxycinnamoyl-CoA derivatives away from monolignol formation and toward other hydroxycinnamoyl derivatives such as those that accumulate during suberization.

  19. Nitrogen recycling during phenylpropanoid metabolism in sweet potato tubers

    Science.gov (United States)

    Singh, S.; Lewis, N. G.; Towers, G. H.

    1998-01-01

    In the first step of the phenylpropanoid metabolic pathway, L-phenylalanine (L-Phe) is deaminated to form E-cinnamate, in a conversion catalyzed by phenylalanine ammonia-lyase (PAL; EC 4.3.1.5). The metabolic fate of the ammonium ion (NH4+) produced in this reaction was investigated in sweet potato (Ipomoea batatas) tuber discs. [15N]-Labeled substrates including L-Phe, in the presence or absence of specific enzyme inhibitors, were administered to sweet potato discs in light under aseptic conditions. 15N-Nuclear magnetic resonance spectroscopic analyses revealed that the 15NH4+ liberated during the PAL reaction is first incorporated into the amide nitrogen of L-glutamine (L-Gln) and then into L-glutamate (L-Glu). These results extend our previous observations in pine and potato that PAL-generated NH4+ is assimilated by the glutamine synthetase (GS; EC 6.3.1.2)/glutamate synthase (GOGAT; EC 1.4.1.13) pathway, with the NH4+ so formed ultimately being recycled back to L-Phe via L-Glu as aminoreceptor and donor.

  20. Salicylic acid in the induction of resistance to beet seedling damping-off and antifungal activity against Fusarium sp., in vitro

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    Douglas Junior Bertoncelli

    2016-02-01

    Full Text Available The damping off is the main disease that affects the beet crop during the seedling production. The aim of this study was to evaluate different salicylic acid (SA concentrations for resistance induction against damping-off in beet seedling and its antifungal activity against Fusarium sp., in vitro condition. Treatment of beet seed was with SA solution by immersion during 5 minutes in the 0.5, 1.0, 1.5 and 2.0 mM concentrations and control (distilled water. It was used four replications with 20 cells by experimental unit. The experiment was carried out for 14 days in cultivate chamber with temperature (23 oC ± 2°C, lighting (12 hours photoperiod and humidity (70% ± 10% controlled. After this time, the germination, damping off incidence, seedling length and fresh mass matter weight were evaluated. It was evaluated also in the seedling tissue the phenylalanine ammonia-lyase (PAL, ?-1.3 glucanase and chitinase level enzymes. In the in vitro the SA was putted in PDA (potato-dextrose-agar medium, where the Fusarium sp. mycelial growth was evaluated. The SA applied for seeds treatment didn’t had effect significant on damping off of beet seedlings, but it induced the activity of ?-1.3 glucanase enzyme, it being this higher in nine times when compared the treatment control. The SA acted in the Fusarium sp. in vitro control with fungitoxic action, suppressed mycelial growth in 28% if compared to control.

  1. Use of silicon as inductor of the resistance in potato to Myzus persicae (Sulzer) (Hemiptera: Aphididae); Uso de silicio como indutor de resistencia em batata a Myzus persicae (Sulzer) (Hemiptera: Aphididae)

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Flavia B.; Moraes, Jair C.; Antunes, Cristiana [Universidade Federal de Lavras, MG (Brazil). Dept. de Entomologia; Santos, Custodio D. dos [Universidade Federal de Lavras, MG (Brazil). Dept. de Quimica

    2008-03-15

    The aphid Myzus persicae (Sulzer) is an important pest of potato and causes direct harm, due to the quantity of sap extracted and for being vector of important phytovirus. This work was carried out to evaluate the action of silicon as a resistance inducer of potato to M. persicae. Four treatments were tried: foliar fertilization with silicon acid at 1%; soil fertilization with 250 ml silicic acid solution at 1%; foliar fertilization with silicon acid at 1% + soil fertilization with 250 ml silicic acid solution at 1%; and a control. The treatments were applied thirty days after the explants emergence. Fifteen days after the application of the treatments, feeding preference and some biological aspects of the aphids were evaluated. After, the content of tannins and lignin present in the leaves and the activity of the enzymes peroxidase and phenylalanine ammonia-lyase were also determined. The silicon fertilization did not affect the preference of the aphids; however it reduced fecundity and the rate of population growth of the insects. The lignin percentage increased in the leaves of plants fertilized with silicon via soil and/or foliar and the percentage of tannins increased only in the leaves fertilized via soil plus foliar. The silicon acted as a resistance inducer to M. persicae in potato. (author)

  2. Manipulation of plant defense responses by the tomato psyllid (Bactericerca cockerelli and its associated endosymbiont Candidatus Liberibacter psyllaurous.

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    Clare L Casteel

    Full Text Available Some plant pathogens form obligate relationships with their insect vector and are vertically transmitted via eggs analogous to insect endosymbionts. Whether insect endosymbionts manipulate plant defenses to benefit their insect host remains unclear. The tomato psyllid, Bactericerca cockerelli (Sulc, vectors the endosymbiont "Candidatus Liberibacter psyllaurous" (Lps during feeding on tomato (Solanum lycopersicum L.. Lps titer in psyllids varied relative to the psyllid developmental stage with younger psyllids harboring smaller Lps populations compared to older psyllids. In the present study, feeding by different life stages of B. cockerelli infected with Lps, resulted in distinct tomato transcript profiles. Feeding by young psyllid nymphs, with lower Lps levels, induced tomato genes regulated by jasmonic acid (JA and salicylic acid (SA (Allene oxide synthase, Proteinase inhibitor 2, Phenylalanine ammonia-lyase 5, Pathogenesis-related protein 1 compared to feeding by older nymphs and adults, where higher Lps titers were found. In addition, inoculation of Lps without insect hosts suppressed accumulation of these defense transcripts. Collectively, these data suggest that the endosymbiont-like pathogen Lps manipulates plant signaling and defensive responses to benefit themselves and the success of their obligate insect vector on their host plant.

  3. Effects of α-aminooxyacetic acid on the level of polyamines, anthocyanins and photosynthetic pigments in seedlings of common buckwheat (Fagopyrum esculentum Moench

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    Marcin Horbowicz

    2011-07-01

    Full Text Available The present paper discusses the effects of α-aminooxyacetic acid (AOA on contents of polyamines, anthocyanins, photosynthetic pigments and phenylalanine ammonia-lyase activity in seedlings of common buckwheat (Fagopyrum esculentum Moench. AOA clearly decreased light-induced formation of anthocyanins and inhibited PAL activity in buckwheat hypocotyls, although a slight stimulatory effect on anthocyanins content in buckwheat cotyledons was observed. AOA declined the contents of chlorophylls a and b and total carotenoids in buckwheat cotyledons. The results show that AOA inhibits phenylpropanoids biosynthesis in buckwheat hypocotyls, and suppress photosynthesis in cotyledons. Moreover, the experiments show that AOA enhances the level of free putrescine in hypocotyls and the level of spermidine in buckwheat cotyledons. AOA also diminished the content of putrescine in cotyledons, but did not affect its level in buckwheat hypocotyls. AOA also substantially declined the level of cadaverine in buckwheat cotyledons, and did not affect its content in hypocotyls. Differences in effect of AOA on anthocyanins and polyamines accumulation indicate various physiological roles of the compounds in buckwheat hypocotyls and cotyledons.

  4. Metabolic reduction of phenylpropanoid compounds in primary leaves of rye (Secale cereale L.) leads to increased UV-B sensitivity of photosynthesis

    International Nuclear Information System (INIS)

    The present study was undertaken in order to investigate the suitability of certain markers for UV plant response. In addition, we attempted to link the internal tissue distribution of specific UV-absorbing compounds to profiles of radiation gradients within intact primary rye leaves (Secale cereale L. cv. Kustro). Etiolated rye seedlings irradiated with low visible light (LL) and/or UV radiation were used to study enzyme activities of the two key enzymes, phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS), together with the tissue-specific accumulation of soluble phenylpropanoid products. Plants grown under relatively high visible light (HL) with or without supplementary UV-B radiation were used for further characterization. Apparent quantum yield and fluorescence quenching parameters were monitored to assess potential physiological changes due to UV-B exposure in HL-grown seedlings. A quartz fibreoptic microprobe was used to characterize the internal UV-B gradient of the leaf. The response of the phenylpropanoid metabolism to UV radiation was similar in primary leaves of both etiolated and HL-treated green plants. The epidermis-specific flavonoids together with CHS activity turned out to be suitable markers for assessing the effect of UV on the phenolic metabolism. The functional role of phenylpropanoid compounds was strongly implicated in protecting rye from UV-B radiation

  5. Regulation of the Phenylpropanoid Pathway: A Mechanism of Selenium Tolerance in Peanut (Arachis hypogaea L.) Seedlings.

    Science.gov (United States)

    Wang, Guang; Wu, Liying; Zhang, Hong; Wu, Wenjia; Zhang, Mengmeng; Li, Xiaofeng; Wu, Hui

    2016-05-11

    To clarify the mechanisms of selenium (Se) tolerance in peanut seedlings, we grew peanut seedlings with sodium selenite (0, 3, and 6 mg/L), and investigated the phenylpropanoids metabolism in seedling roots. The results showed that selenite up-regulated the expression of genes and related enzyme activities involving in the phenylpropanoids biosynthesis cascade, such as phenylalanine ammonia-lyase, trans-cinnamate-4-hydroxylase, chalcone synthase, chalcone isomerase, and cinnamyl-alcohol dehydrogenase. Selenite significantly increased phenolic acids and flavonoids, which contributed to the alleviation of selenite-induced stress. Moreover, selenite enhanced the formation of endodermis in roots, which may be attributed to the up-regulation of lignin biosynthesis mediated by the selenite-induced changes of H2O2 and NO, which probably regulated the selenite uptake from an external medium. Accumulation of polyphenolic compounds via the phenylpropanoid pathway may be one of the mechanisms of the increasing selenite tolerance in plants, by which peanut seedlings survived in seleniferous soil, accompanied by accumulation of Se. PMID:27089243

  6. Biochemical analysis of plant protection afforded by a nonpathogenic endophytic mutant of Colletotrichum magna

    Energy Technology Data Exchange (ETDEWEB)

    Redman, R.S.; Rodriguez, R.J. (Geological Survey, Seattle, WA (United States) Univ. of Washington, Seattle, WA (United States). Dept. of Botany); Clifton, D.R.; Morrel, J.; Brown, G. (Geological Survey, Seattle, WA (United States)); Freeman, S. (Volcani Center, Bet Dagan (Israel). Dept. of Plant Pathology)

    1999-02-01

    A nonpathogenic mutant of Colletotrichum magna (path-1) was previously shown to protect watermelon (Citrullus lanatus) and cucumber (Cucumis sativus) seedlings from anthracnose disease elicited by wild-type C. magna. Disease protection was observed in stems of path-1-colonized cucurbits but not in cotyledons, indicating that path-1 conferred tissue-specific and/or localized protection. Plant biochemical indicators of a localized and systemic (peroxidase, phenylalanine ammonia-lyase, lignin, and salicylic acid) plant-defense response were investigated in anthracnose-resistant and-susceptible cultivars of cucurbit seedlings exposed to four treatments: (1) water (control), (2) path-1 conidia, (3) wild-type conidia, and (4) challenge conditions (inoculation into path-1 conidia for 48 h and then exposure to wild-type conidia). Collectively, these analyses indicated that disease protection in path-1-colonized plants was correlated with the ability of these plants to mount a defense response more rapidly and to equal or greater levels than plants exposed to wild-type C. magna alone. Watermelon plants colonized with path-1 were also protected against disease caused by Colletotrichum orbiculare and Fusarium oxysporum. A model based on the kinetics of plant-defense activation is presented to explain the mechanism of path-1-conferred disease protection.

  7. Beneficial behavior of nitric oxide in copper-treated medicinal plants.

    Science.gov (United States)

    Liu, Shiliang; Yang, Rongjie; Pan, Yuanzhi; Ren, Bo; Chen, Qibing; Li, Xi; Xiong, Xi; Tao, Jianjun; Cheng, Qingsu; Ma, Mingdong

    2016-08-15

    Despite numerous reports implicating nitric oxide (NO) in the environmental-stress responses of plants, the specific metabolic and ionic mechanisms of NO-mediated adaptation to metal stress remain unclear. Here, the impacts of copper (Cu) and NO donor (SNP, 50μM) alone or in combination on the well-known medicinal plant Catharanthus roseus L. were investigated. Our results showed that Cu markedly increased Cu(2+) accumulation, decreased NO production, and disrupted mineral equilibrium and proton pumps, thereby stimulating a burst of ROS; in addition, SNP ameliorates the negative toxicity of Cu, and cPTIO reverses this action. Furthermore, the accumulations of ROS and NO resulted in reciprocal changes. Interestingly, nearly all of the investigated amino acids and the total phenolic content in the roots were promoted by the SNP treatment but were depleted by the Cu+SNP treatment, which is consistent with the self-evident increases in phenylalanine ammonia-lyase activity and total soluble phenol content induced by SNP. Unexpectedly, leaf vincristine and vinblastine as well as the total alkaloid content (ca. 1.5-fold) were decreased by Cu but markedly increased by SNP (+38% and +49% of the control levels). This study provides the first evidence of the beneficial behavior of NO, rather than other compounds, in depleting Cu toxicity by regulating mineral absorption, reestablishing ATPase activities, and stimulating secondary metabolites. PMID:27131454

  8. Variation in physiological and chemical characteristics at developmental stage in different disease-resistant varieties of camellia oleifera

    International Nuclear Information System (INIS)

    Camellia oleifera Abel. is an important edible oil tree species from Southern China. Anthracnose, caused by Colletotrichum gloeosporioides (Penz.), is responsible for more than 50% of C. oleifera production loss, and C. oleifera varieties differ in their resistance to anthracnose. The aim of this study was to assess resistance mechanisms by monitoring physiological and biochemical parameters of differentially resistant cultivars during the development of C. oleifera. C. oleifera fruit coats were analyzed between May and September for tannins, anthocyanins, soluble sugar content, pH, buffer capacity, activity of three enzyme (Phenylalanine ammonia lyase; polyphenol oxidase; peroxidase) and free radical scavenging capacity. Anthocyanins, soluble contents and free radical scavenging capacity were related to anthracnose resistance, with anthocyanins and soluble sugar contents of the resistant varieties nearly twofold higher than those of susceptible varieties. The results of free radical scavenging capacity showed that extracts from highly resistant varieties of C. oleifera fruit coats performed more efficiently in the scavenging of free radicals than those from susceptible varieties. The three enzyme activities of highly resistant varieties rose rapidly and continuously, while those of medium resistant and highly susceptible varieties increased initially and then decreased. Tannins, pH and buffer capacity showed no significant differences between different cultivars. This study broadens the understanding of disease resistance mechanisms in C. oleifera. (author)

  9. RNAi down-regulation of cinnamate-4-hydroxylase increases artemisinin biosynthesis in Artemisia annua

    Science.gov (United States)

    Kumar, Ritesh; Vashisth, Divya; Misra, Amita; Akhtar, Md Qussen; Jalil, Syed Uzma; Shanker, Karuna; Gupta, Madan Mohan; Rout, Prashant Kumar; Gupta, Anil Kumar; Shasany, Ajit Kumar

    2016-01-01

    Cinnamate-4-hydroxylase (C4H) converts trans-cinnamic acid (CA) to p-coumaric acid (COA) in the phenylpropanoid/lignin biosynthesis pathway. Earlier we reported increased expression of AaCYP71AV1 (an important gene of artemisinin biosynthesis pathway) caused by CA treatment in Artemisia annua. Hence, AaC4H gene was identified, cloned, characterized and silenced in A. annua with the assumption that the elevated internal CA due to knock down may increase the artemisinin yield. Accumulation of trans-cinnamic acid in the plant due to AaC4H knockdown was accompanied with the reduction of p-coumaric acid, total phenolics, anthocyanin, cinnamate-4-hydroxylase (C4H) and phenylalanine ammonia lyase (PAL) activities but increase in salicylic acid (SA) and artemisinin. Interestingly, feeding trans-cinnamic acid to the RNAi line increased the level of artemisinin along with benzoic (BA) and SA with no effect on the downstream metabolites p-coumaric acid, coniferylaldehyde and sinapaldehyde, whereas p-coumaric acid feeding increased the content of downstream coniferylaldehyde and sinapaldehyde with no effect on BA, SA, trans-cinnamic acid or artemisinin. SA is reported earlier to be inducing the artemisinin yield. This report demonstrates the link between the phenylpropanoid/lignin pathway with artemisinin pathway through SA, triggered by accumulation of trans-cinnamic acid because of the blockage at C4H. PMID:27220407

  10. Effect of Chlorocholine Chloride on Chlorophyll, Photosynthesis, Soluble Sugar and Flavonoids of Ginkgo biloba

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    Weiwei ZHANG

    2013-05-01

    Full Text Available The flavonoids content determines the quality characteristics of Ginkgo biloba extract that could be increased by using of plant growth regulators. The objective of study was to investigate the effect of chlorocholine chloride (CCC, an anti-gibberellin growth retardant, on photosynthesis, chlorophyll, soluble sugar, total amino acids and phenylalanine contents, flavonoid accumulation, and flavonoids enzyme activity in G. biloba leaves. The ginkgo seedlings were grown in the greenhouse conditions with foliar applications of 0 (control, 0.5, 1.0 and 2.0 g l-1 CCC. Results showed that 0.5, 1.0 and 2.0 g l-1 CCC treatments significantly increased photosynthetic rates of leaves, the contents of chlorophyll, soluble sugar, total amino acids and phenylalnine in ginkgo leaves. Total polyphenols, flavonoids, anthocyanins content, phenylalanine ammonia-lyase (PAL, chalcone synthase (CHS and chalcone isomerase (CHI activities were all significantly increased by 1.0 and 2.0 g l-1 CCC treatments. Foliar treatment with CCC therefore might be a useful means of improving pharmacological properties of G. biloba leaves.

  11. Ultrasound treatment on phenolic metabolism and antioxidant capacity of fresh-cut pineapple during cold storage.

    Science.gov (United States)

    Yeoh, Wei Keat; Ali, Asgar

    2017-02-01

    Ultrasound treatment at different power output (0, 25 and 29W) and exposure time (10 and 15min) was used to investigate its effect on the phenolic metabolism enzymes, total phenolic content and antioxidant capacity of fresh-cut pineapple. Following ultrasound treatment at 25 and 29W, the activity of phenylalanine ammonia lyase (PAL) was increased significantly (P<0.05) by 2.0 and 1.9-fold, when compared to control. Meanwhile, both the activity of polyphenol oxidase (PPO) and polyphenol peroxidase (POD) in fresh-cut pineapple was significantly (P<0.05) lower than control upon subjected to ultrasound treatment. In the present study, induction of PAL was found to significantly (P<0.001) correlate with higher total phenolic content and thus higher antioxidant capacity in fresh-cut pineapple. Results suggest that hormetic dosage of ultrasound treatment can enhance the activity of PAL and total phenolic content and hence the total antioxidant capacity to encounter with oxidative stress. PMID:27596416

  12. Allocation of secondary metabolites, photosynthetic capacity, and antioxidant activity of Kacip Fatimah (Labisia pumila Benth) in response to CO2 and light intensity.

    Science.gov (United States)

    Ibrahim, Mohd Hafiz; Jaafar, Hawa Z E; Karimi, Ehsan; Ghasemzadeh, Ali

    2014-01-01

    A split plot 3 by 4 experiment was designed to investigate and distinguish the relationships among production of secondary metabolites, soluble sugar, phenylalanine ammonia lyase (PAL; EC 4.3.1.5) activity, leaf gas exchange, chlorophyll content, antioxidant activity (DPPH), and lipid peroxidation under three levels of CO2 (400, 800, and 1200 μ mol/mol) and four levels of light intensity (225, 500, 625, and 900 μ mol/m(2)/s) over 15 weeks in Labisia pumila. The production of plant secondary metabolites, sugar, chlorophyll content, antioxidant activity, and malondialdehyde content was influenced by the interactions between CO2 and irradiance. The highest accumulation of secondary metabolites, sugar, maliondialdehyde, and DPPH activity was observed under CO2 at 1200 μ mol/mol + light intensity at 225 μ mol/m(2)/s. Meanwhile, at 400 μ mol/mol CO2 + 900 μ mol/m(2)/s light intensity the production of chlorophyll and maliondialdehyde content was the highest. As CO2 levels increased from 400 to 1200 μ mol/mol the photosynthesis, stomatal conductance, f v /f m (maximum efficiency of photosystem II), and PAL activity were enhanced. The production of secondary metabolites displayed a significant negative relationship with maliondialdehyde indicating lowered oxidative stress under high CO2 and low irradiance improved the production of plant secondary metabolites that simultaneously enhanced the antioxidant activity (DPPH), thus improving the medicinal value of Labisia pumila under this condition. PMID:24683336

  13. EVALUATION OF BIOLOGICAL EFFICACY OF TRICHODERMA SPECIES ISOLATES AGAINST ALTERNARIA LEAF SPOT DISEASE OF SESAME

    Directory of Open Access Journals (Sweden)

    A. S. Lubaina

    2015-03-01

    Full Text Available Alternaria leaf spot disease is a major threat to sesame (Sesamum orientale L. caused by Alternari asesami. Induced resistance is an alternative to systemic disease resistance response of plants. The present study aims to evaluate Trichoderma species efficacy as biocontrol via induction of resistance against A. sesami in sesame species. During in vitro bio control test, T. harzianum colonize and parallely inhibit the growth of the fungal pathogen. Expression of various defence related enzymes observed in sesame induce resistance against the pathogen infection in the host. T. harzianum coupled with inoculation of A. sesami enhance the remarkable induction of defence enzyme such as peroxidase (POX, polyphenol oxidase (PPO, phenylalanine ammonia lyase (PAL and also the phenolic content compared with the control. The enzyme activity increased from 48 h of sampling and peaked at 72 h and then decreased after 72 h. In greenhouse and field experiments, soil treatment with a powder formulation of T. harzianum two weeks before planting or at the time of planting reduced significantly the incidence of diseases on both the wild and cultivar Thilarani.The results demonstrate that T. harzianumcan be successfully applied as a biological control against Alternaria leaf spot disease in sesame.

  14. Arabidopsis CAPRICE (MYB and GLABRA3 (bHLH control tomato (Solanum lycopersicum anthocyanin biosynthesis.

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    Takuji Wada

    Full Text Available In Arabidopsis thaliana the MYB transcription factor CAPRICE (CPC and the bHLH transcription factor GLABRA3 (GL3 are central regulators of root-hair differentiation and trichome initiation. By transforming the orthologous tomato genes SlTRY (CPC and SlGL3 (GL3 into Arabidopsis, we demonstrated that these genes influence epidermal cell differentiation in Arabidopsis, suggesting that tomato and Arabidopsis partially use similar transcription factors for epidermal cell differentiation. CPC and GL3 are also known to be involved in anthocyanin biosynthesis. After transformation into tomato, 35S::CPC inhibited anthocyanin accumulation, whereas GL3::GL3 enhanced anthocyanin accumulation. Real-time reverse transcription PCR analyses showed that the expression of anthocyanin biosynthetic genes including Phe-ammonia lyase (PAL, the flavonoid pathway genes chalcone synthase (CHS, dihydroflavonol reductase (DFR, and anthocyanidin synthase (ANS were repressed in 35S::CPC tomato. In contrast, the expression levels of PAL, CHS, DFR, and ANS were significantly higher in GL3::GL3 tomato compared with control plants. These results suggest that CPC and GL3 also influence anthocyanin pigment synthesis in tomato.

  15. Modular optimization of heterologous pathways for de novo synthesis of (2S-naringenin in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Junjun Wu

    Full Text Available Due to increasing concerns about food safety and environmental issues, bio-based production of flavonoids from safe, inexpensive, and renewable substrates is increasingly attracting attention. Here, the complete biosynthetic pathway, consisting of 3-deoxy-D-arabinoheptulosonate 7-phosphate synthase (DAHPS, chorismate mutase/prephenate dehydrogenase (CM/PDH, tyrosine ammonia lyase (TAL, 4-coumarate:CoA ligase (4CL, chalcone synthase (CHS, chalcone isomerase (CHI, malonate synthetase, and malonate carrier protein, was constructed using pre-made modules to overproduce (2S-naringenin from D-glucose. Modular pathway engineering strategies were applied to the production of the flavonoid precursor (2S-naringenin from L-tyrosine to investigate the metabolic space for efficient conversion. Modular expression was combinatorially tuned by modifying plasmid gene copy numbers and promoter strengths to identify an optimally balanced pathway. Furthermore, a new modular pathway from D-glucose to L-tyrosine was assembled and re-optimized with the identified optimal modules to enable de novo synthesis of (2S-naringenin. Once this metabolic balance was achieved, the optimum strain was capable of producing 100.64 mg/L (2S-naringenin directly from D-glucose, which is the highest production titer from D-glucose in Escherichia coli. The fermentation system described here paves the way for the development of an economical process for microbial production of flavonoids.

  16. Enhanced biosynthesis of quercetin occurs as A photoprotective measure in Lycopersicon esculentum mill. under Acute UV-B exposure

    Directory of Open Access Journals (Sweden)

    Abhilasha Shourie

    2014-06-01

    Full Text Available Lycopersicon esculentum respond to UV-B by enhanced synthesis of flavonoid quercetin, a strong antioxidant that helps the plants to well acclimatize to UV-B stress. Three weeks old plants of L. esculentum were subjected to acute UV-B irradiation for 20, 40 and 60 minutes daily until 28 days and analyzed for the morphological and biochemical changes. UV-B exposure for 40 and 60 minutes considerably affected the growth and biomass of L. esculentum. The leaves were deformed, developed chlorosis and abscised early as compared to the unexposed plants. Biomass declined by 35% and total chlorophyll decreased by 24.7% due to disintegration of chloroplasts. Enhancement was seen in the content of carotenoids, anthocyanins and total flavonoids by 15, 33.3 and 22.8%, respectively, which was attributed to the photoprotective role of these compounds as potential quenchers of excess excitation energy. Quercetin content decreased on UV-B exposure to 20 and 40 min, and thereafter increased significantly by 5.19% on 60 min of exposure. This pattern probably indicated that the over-expression of genes involved in its biosynthesis such as phenylalanine ammonia lyase (PAL, chalcone synthase (CHS, flavanone 3-hydroxylase (F3H and dihydroflavonol 4-reductase (DFR occurred only after certain threshold exposure (60 min, which could be the strategy for developing tolerance against UV-B stress in L. esculentum.

  17. Induction of stilbene biosynthesis as an early indicator of ozone stress in spruce (Pinus sylvestris L.); Die Induktion der Stilben-Biosynthese als frueher Indikator einer Ozonbelastung bei der Kiefer (Pinus sylvestris L.)

    Energy Technology Data Exchange (ETDEWEB)

    Rosemann, D.

    1990-07-03

    For an investigation on the effect of ozone on phenyl propane metabolism in conifers, spruce shoots aged six weeks were used as model systems. Time-related synthesis of the stilbenes pinosylvin and pinosylvin-3-methyl ether as a function of stress was determined. Furthermore, solubilization and test methods were developed with a view to the measurement of phenyl alanine ammonia lyase, stilbene synthase and chalcone synthase. The results were transferable to several-year-old spruces in exposure chambers and in the field. They are in good agreement with the visible symptoms of damage to be observed only later. (LU) [Deutsch] Als Modellsysteme zur Untersuchung der Ozonwirkung auf den Phenylpropanstoffwechsel bei Koniferen wurden 6 Wochen alte Kiefernkeimlinge verwendet. Die zeitliche Neubildung der Stilbene Pinosylvin und Pinosylvin-3-Methylether wurde in Abhaengigkeit von der Belastung bestimmt. Weiter wurden zur Messung von Phenylalanin-Ammoniak-Lyase, Stilbenesynthase und Chalconsynthase Aufschluss- und Testmethoden entwickelt. Die Ergebnisse konnten auf mehrjaehrige Kiefern in Expositionskammern und im Freiland uebertragen werden. Sie korrelieren gut mit den erst spaeter zu beobachtenden sichtbaren Schadsymptomen. (LU)

  18. Promotive Effects of Alginate-Derived Oligosaccharides on the Inducing Drought Resistance of Tomato

    Institute of Scientific and Technical Information of China (English)

    LIU Ruizhi; JIANG Xiaolu; GUAN Huashi; LI Xiaoxia; DU Yishuai; WANG Peng; MOU Haijin

    2009-01-01

    In order to determine the role of alginate-derived oligosaccharides (ADO) in drought stress resistance of tomato (Lycopersicon esculentum Miller) seedlings, the leaves were exposed to different concentrations of ADO (0.05%, 0.10%, 0.20%, 0.30% and 0.50%) after drought stress was simulated by exposing the roots to 0.6molL-I PEG-6000 solution for 6h. Changes in biomass, electrolyte leakage and malondialdehyde (MDA), free proline, total soluble sugars (TSS) and abscisic acid (ABA), the enzyme activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) were measured to investigate the effects of ADO treatment. The results showed that the treatment with an ADO concentration of 0.20% exhibited the highest performance of drought stress resistance in the tomato seedlings by decreasing the electrolyte leakage and the concentration of MDA, increasing the contents of free proline, TSS and ABA, and increasing the activities of CAT, SOD, POD and PAL after treatment with ADO. It is suggested that changes in electrolyte leakage, MDA, osmotic solutes, ABA, anti-oxidative enzyme and PAL activities were responsible for the increased drought stress resistance in tomato seedlings. To our best knowledge, this is the first report of the effect of ADO treatment on enhancing the drought stress resistance of tomato seedlings.

  19. Physiological responses of root-less epiphytic plants to acid rain.

    Science.gov (United States)

    Kováčik, Jozef; Klejdus, Bořivoj; Bačkor, Martin; Stork, František; Hedbavny, Josef

    2011-03-01

    Selected physiological responses of Tillandsia albida (Bromeliaceae) and two lichens (Hypogymnia physodes and Xanthoria parietina) exposed to simulated acid rain (AR) over 3 months were studied. Pigments were depressed in all species being affected the most in Tillandsia. Amounts of hydrogen peroxide and superoxide were elevated and soluble proteins decreased only in AR-exposed Hypogymnia. Free amino acids were slightly affected among species and only glutamate sharply decreased in AR-exposed Xanthoria. Slight increase in soluble phenols but decrease in flavonoids in almost all species suggests that the latter are not essential for tolerance to AR. Almost all phenolic acids in Tillandsia leaves decreased in response to AR and activities of selected enzymes (phenylalanine ammonia-lyase, polyphenol oxidase, ascorbate- and guaiacol-peroxidase) were enhanced by AR. In lichens, considerable increase in metabolites (physodalic acid, atranorin and parietin) in response to AR was found but amount of ergosterol was unchanged. Macronutrients (K, Ca, Mg) decreased more pronouncedly in comparison with micronutrients in all species. Xanthoria showed higher tolerance in comparison with Hypogymnia, suggesting that could be useful for long-term biomonitoring. PMID:21161375

  20. Feasibility of radiation processing for post-harvest storage of potatoes under tropical conditions

    International Nuclear Information System (INIS)

    Storage changes after gamma irradiation (10krad) of five commercial varieties of potatoes, Kufri Chandramukhi, K. Kuber, K. Alankar, K. Sheetman and K. Sinduri, grown in India were ascertained to arrive at optimal storage conditions. The radiation treatment could completely inhibit sprouting in all the varieties, irrespective of storage temperature, in addition to eliminating the tuber moth Pthorimaea operculella (Zeller). The temperature-dependent total losses could be attributed to microbial rotting and dehydration. The organisms causing soft rot at temperatures above 150C belonged to Erwinia spp., while the rot caused below 100C was essentially due to Micrococcus spp. Irradiation followed by storage at cool temperatures (10-150C) offers an alternative method, comparable with conventional refrigerated (2-40C) storage. The irradiated potatoes were not amenable to the attack of toxigenic fungi Aspergillus flavus and A. parasiticus during storage. This could be attributed to phenolic compounds present in the tubers. Phenylalanine ammonia lyase (PAL), involved in the metabolism of phenolic compounds, showed enhancement in the irradiated potatoes. The extent of radiation-induced activation of PAL is suggested as a biochemical parameter for identifying irradiated tubers. (author)

  1. Feasibility of Radiation Processing for Post-Harvest Storage of Potatoes Under Tropical Conditions

    International Nuclear Information System (INIS)

    Storage changes after gamma irradiation (10 krad) of five commercial varieties of potatoes, Kufri Chandramukhi, K. Kuber, K. Alankar, K. Sheetman and K. Sinduri, grown in India were ascertained to arrive at optimal storage conditions. The radiation treatment could completely inhibit sprouting in all the varieties, irrespective of storage temperature, in addition to eliminating the tuber moth Pthorimaea operculella (Zeller). The temperature-dependent total losses could be attributed to microbial rotting and dehydration. The organisms causing soft rot at temperatures above 15°C belonged to Erwinia spp., while the rot caused below 10°C was essentially due to Micrococcus spp. Irradiation followed by storage at cool temperatures (10-15°C) offers an alternative method, comparable with conventional refrigerated (2-4°C) storage. The irradiated potatoes were not amenable to the attack of toxigenic fungi Aspergillus flavus and A. parasiticus during storage. This could be attributed to phenolic compounds present in the tubers. Phenylalanine ammonia lyase (PAL), involved in the metabolism of phenolic compounds, showed enhancement in the irradiated potatoes. The extent of radiation induced activation of PAL is suggested as a biochemical parameter for identifying irradiated tubers. (author)

  2. Induction of aromatic amino acids and phenylpropanoid compounds in Scrophularia striata Boiss. cell culture in response to chitosan-induced oxidative stress.

    Science.gov (United States)

    Kamalipourazad, Maryam; Sharifi, Mohsen; Maivan, Hassan Zare; Behmanesh, Mehrdad; Chashmi, Najmeh Ahmadian

    2016-10-01

    Manipulation of cell culture media by elicitors is one of most important strategies to inducing secondary metabolism for the production of valuable metabolites. In this investigation, inducing effect of chitosan on physiological, biochemical, and molecular parameters were investigated in cell suspension cultures of Scrophularia striata Boiss. The results showed that chitosan concentration and time of elicitation are determinants of the effectiveness of the elicitor. Accumulation of aromatic amino acids (phenylalanine [Phe] and tyrosine [Tyr]), phenylpropanoid compounds (phenolic acids [PAs] and echinacoside [ECH]), hydrogen peroxide (H2O2) production, phenylalanine ammonia-lyase (PAL) activity and gene expression, and antioxidant enzymes (superoxide dismutase [SOD], peroxidase [POX], catalase [CAT]) activities were altered by changing the exposure time of elicitation. Results showed that, upon elicitation with chitosan, oxidative events were induced, antioxidant responses of S. striata cells were boosted through enhanced activity of an effective series of scavenging enzymes (SOD, CAT, and POX), and biosynthesis of non-enzymatic antioxidants (ECH and PAs [cinnamic, p-coumaric and, caffeic acids]). The increase in amino acid content and PAL activity at early days of exposure to chitosan was related with rises in phenolic compounds. These results provide evidence that chitosan by up-regulation of PAL gene differentially improves the production of phenylpropanoid compounds, which are of medical commercial value with good biotechnological prospects. PMID:27392152

  3. Differential induction of acquired resistance and PR gene expression in tobacco by virus infection, ethephon treatment, UV light and wounding

    International Nuclear Information System (INIS)

    Genes for acidic, extracellular and basic, intracellular pathogenesis-related (PR) proteins of tobacco were studied for their response to tobacco mosaic virus (TMV) infection, ethephon treatment, wounding and UV light. The genes encoding the acidic PR proteins (PR-1, PR-2, PR-3, PR-4 and PR-5) responded similarly to the different forms of stress. They appeared to be highly inducible by TMV, moderately inducible by ethephon treatment and UV light and not inducible by wounding. The genes for the basic counterparts of PR-1, PR-2, PR-3 and PR-5 also displayed a common stress response. However, this response was different from that of the acidic PR proteins. Here, the highest induction was obtained upon ethephon treatment, while the other stress conditions resulted in somewhat lower levels of expression. Most genes for acidic PR proteins are systemically induced in the uninfected upper leaves of TMV-infected plants, whereas the genes encoding the basic PR proteins are not. Increased levels of resistance to TMV, comparable to resistance obtained by pre-infection with the virus, were found in UV-irradiated leaves but not in wounded or ethephon-treated leaves. This indicates that the basic PR proteins are not involved in resistance to TMV infection. Tobacco phenylalanine ammonia-lyase genes were not inducible by the various stress conditions. The implications of these findings in relation to the phenomenon of acquired resistance are discussed

  4. A novel process for obtaining pinosylvin using combinatorial bioengineering in Escherichia coli.

    Science.gov (United States)

    Liang, Jing-Long; Guo, Li-Qiong; Lin, Jun-Fang; He, Ze-Qi; Cai, Fa-Ji; Chen, Jun-Fei

    2016-06-01

    Pinosylvin as a bioactive stilbene is of great interest for food supplements and pharmaceuticals development. In comparison to conventional extraction of pinosylvin from plant sources, biosynthesis engineering of microbial cell factories is a sustainable and flexible alternative method. Current synthetic strategies often require expensive phenylpropanoic precursor and inducer, which are not available for large-scale fermentation process. In this study, three bioengineering strategies were described to the development of a simple and economical process for pinosylvin biosynthesis in Escherichia coli. Firstly, we evaluated different construct environments to give a highly efficient constitutive system for enzymes of pinosylvin pathway expression: 4-coumarate: coenzyme A ligase (4CL) and stilbene synthase (STS). Secondly, malonyl coenzyme A (malonyl-CoA) is a key precursor of pinosylvin bioproduction and at low level in E. coli cell. Thus clustered regularly interspaced short palindromic repeats interference (CRISPRi) was explored to inactivate malonyl-CoA consumption pathway to increase its availability. The resulting pinosylvin content in engineered E. coli was obtained a 1.9-fold increase depending on the repression of fabD (encoding malonyl-CoA-ACP transacylase) gene. Eventually, a phenylalanine over-producing E. coli consisting phenylalanine ammonia lyase was introduced to produce the precursor of pinosylvin, trans-cinnamic acid, the crude extraction of cultural medium was used as supplementation for pinosylvin bioproduction. Using these combinatorial processes, 47.49 mg/L pinosylvin was produced from glycerol. PMID:27116968

  5. Identification of processed Japanese green tea based on polymorphisms generated by STS-RFLP analysis.

    Science.gov (United States)

    Kaundun, Shiv S; Matsumoto, Satoru

    2003-03-26

    In Japan, tea is generally sold blended, though 90% of the total production is clonal. Due to the increasingly strict consumer need and taste, however, more and more Japanese green teas are being sold under their particular cultivar name. Moreover, tea made from Yabukita, a much appreciated cultivar originally developed in Japan, has recently been produced and imported from a neighboring country. This paper describes a simple and inexpensive methodology capable of identifying fresh and processed Japanese green teas to discourage its fraudulent commercialization. The study was based on 46 main tea cultivars, and polymorphism detected through STS-RFLP analysis of the coding and noncoding DNA regions of three genes, namely phenylalanine ammonia-lyase, chalcone synthase, and dihydroflavonol 4-reductase, for which nucleotide information was available. All 46 tea cultivars analyzed could be easily distinguished using a combination of codominant DNA markers. Yabukita displayed a unique profile when PAL intron was digested with DdeI, thus allowing its rapid authentication at low cost. PMID:12643627

  6. Production of ready-to-eat lentil sprouts with improved antioxidant capacity: optimization of elicitation conditions with hydrogen peroxide.

    Science.gov (United States)

    Świeca, Michał

    2015-08-01

    This study evaluates the optimal conditions for elicitation with H2O2 for improving the antioxidant capacity of lentil sprouts. Generally, except for 3-day-old sprouts, elicitation increased phenolic content (in respect to the control). The highest phenolic content was determined for 2-day-old sprouts treated with 15 mM H2O2 (0.71 mg/gf.m.). All the studied modifications increased the antioxidant potential of sprouts. The highest elevation (3.2-fold) was found for 5-day-old sprouts (single 15 mM H2O2 treatment). A significant increase was also found on the 2nd and 4th days (2.13- and 2.14-fold, respectively). Elicitation induced tyrosine and phenylalanine ammonia-lyases activities. H2O2 treatments induced the activity of catalase - especially for 2-day-old sprouts treated with 150 mM H2O2 (597 U/gf.m.). Elicitation with H2O2 is a useful tool for designing some features of sprouts. Phenolic content and antioxidant capacity are strongly affected by concentration of the elicitor, and time and intervals of its application. PMID:25766821

  7. Phyllosticta musarum Infection-Induced Defences Suppress Anthracnose Disease Caused by Colletotrichum musae in Banana Fruits cv 'Embul'.

    Science.gov (United States)

    Abayasekara, C L; Adikaram, N K B; Wanigasekara, U W N P; Bandara, B M R

    2013-03-01

    Anthracnose development by Colletotrichum musae was observed to be significantly less in the fruits of the banana cultivar 'Embul' (Mysore, AAB) infected with Phyllosticta musarum than in fruits without such infections. Anthracnose disease originates from quiescent C. musae infections in the immature fruit. P. musarum incites minute, scattered spots, referred to as freckles, in the superficial tissues of immature banana peel which do not expand during maturation or ripening. P. musarum does not appear to have a direct suppressive effect on C. musae as conidia of C. musae germinate on both freckled and non-freckled fruit forming quiescent infections. Our investigations have shown that P. musarum infection induced several defence responses in fruit including the accumulation of five phytoalexins, upregulation of chitinase and β-1,3-glucanase, phenylalanine ammonia lyase (PAL) activity and cell wall lignification. (1)H and (13)C NMR spectral data of one purified phytoalexin compared closely with 4'-hydroxyanigorufone. Some of the P. musarum-induced defences that retained during ripening, restrict C. musae development at the ripe stage. This paper examines the potential of P. musarum-induced defences, in the control of anthracnose, the most destructive postharvest disease in banana. PMID:25288931

  8. Phyllosticta musarum Infection-Induced Defences Suppress Anthracnose Disease Caused by Colletotrichum musae in Banana Fruits cv ‘Embul’

    Science.gov (United States)

    Abayasekara, C. L.; Adikaram, N. K. B.; Wanigasekara, U. W. N. P.; Bandara, B. M. R.

    2013-01-01

    Anthracnose development by Colletotrichum musae was observed to be significantly less in the fruits of the banana cultivar ‘Embul’ (Mysore, AAB) infected with Phyllosticta musarum than in fruits without such infections. Anthracnose disease originates from quiescent C. musae infections in the immature fruit. P. musarum incites minute, scattered spots, referred to as freckles, in the superficial tissues of immature banana peel which do not expand during maturation or ripening. P. musarum does not appear to have a direct suppressive effect on C. musae as conidia of C. musae germinate on both freckled and non-freckled fruit forming quiescent infections. Our investigations have shown that P. musarum infection induced several defence responses in fruit including the accumulation of five phytoalexins, upregulation of chitinase and β-1,3-glucanase, phenylalanine ammonia lyase (PAL) activity and cell wall lignification. 1H and 13C NMR spectral data of one purified phytoalexin compared closely with 4′-hydroxyanigorufone. Some of the P. musarum-induced defences that retained during ripening, restrict C. musae development at the ripe stage. This paper examines the potential of P. musarum-induced defences, in the control of anthracnose, the most destructive postharvest disease in banana. PMID:25288931

  9. The Efficacy and Underlying Mechanism of Sulfone Derivatives Containing 1,3,4-oxadiazole on Citrus Canker

    Directory of Open Access Journals (Sweden)

    Pei Li

    2015-08-01

    Full Text Available The objectives of the current study were to isolate and identify the pathogen responsible for citrus canker and investigate the efficacy of sulfone derivatives containing 1,3,4-oxadiazole moiety on controlling citrus canker caused by Xanthomonas citri subsp. citri (Xcc under in vitro and field conditions. In an in vitro study, we tested eight sulfone derivatives against Xcc and the results demonstrated that compound 3 exhibited the best antibacterial activity against Xcc, with a half-maximal effective concentration (EC50 value of 1.23 μg/mL, which was even better than those of commercial bactericides Kocide 3000 (58.21 μg/mL and Thiodiazole copper (77.04 μg/mL, respectively. Meanwhile, under field experiments, compound 3 treatments demonstrated the highest ability to reduce the disease of citrus canker in leaves and fruits in two different places relative to an untreated control as well as the commercial bactericides Kocide 3000 and Thiodiazole copper. Meanwhile, compound 3 could stimulate the increase in peroxidase (POD, polyphenol oxidase (PPO, and phenylalanine ammonia lyase (PAL activities in the navel orange leaves, causing marked enhancement of plant resistance against citrus canker. Moreover, compound 3 could damage the cell membranes, destruct the biofilm formation, inhibit the production of extracellular polysaccharide (EPS, and affect the cell membrane permeability to restrain the growth of the bacteria.

  10. Expression of a Magnaporthe grisea Elicitor and Its Biological Function in Activating Resistance in Rice

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The expression of a protein elicitor from Magnaporthe griesea and its biological function in activating resistance in rice (Oryza sativa L) were reported. The gene of elicitor was expressed in Escherichia coli cells and produced a His6-fusion protein with 42 kD apparent molecular weight on SDS-PAGE. The purified protein could induce the resistance to blast disease, with the control efficiency of 46.47% and 36.41% at the 14th day and the 21st day after blast inoculation, respectively.After treatment with the expressed protein, the phenylalanine ammonia-lyase (PAL) and peroxidase (POD) activities were promoted in rice plants, meanwhile, the transcription levels of STKM, FAD, PBZ1 and PR1 genes were increased in rice plants. Moreover, after comparing the profile of total rice leaf proteins on two-dimensional eiectrophoresis gel, about 14proteins were found to be increased in expression level after the expressed protein treatment. All the results indicated that the expressed protein could act as an elicitor to trigger the resistance in rice.

  11. Inhibitory effect and enzymatic analysis of E-cinnamaldehyde against sclerotinia carrot rot.

    Science.gov (United States)

    Ojaghian, Mohammad Reza; Wang, Qi; Li, Xiaolin; Sun, Xiaoting; Xie, Guan-Lin; Zhang, Jingze; Hai-Wei, Fan; Wang, Li

    2016-02-01

    This study was conducted to determine the inhibitory effect of E-cinnamaldehyde (EC) against causal agent of storage carrot rot, Sclerotinia sclerotiorum, under in vivo and in vitro conditions. Based on the results, EC was able to completely inhibit mycelial growth of three isolates (P>0.05) in both volatile and contact phases after 6days at the concentrations 200μl and 1μl/ml, respectively. In addition, EC at concentrations 1 and 10μl/ml completely inhibited carpogenic germination of three isolates. The results of in vivo trials showed that EC at the concentration of 10μl/ml was able to control the disease caused by isolates 1 and 3. However the disease caused by isolate 2 was inhibited with the concentration of 20μl/ml. In enzyme analyses, the activity of polyphenoloxidase and peroxidase did not change in the inoculated carrots after application of EC. Furthermore, the level of phenylalanine ammonia lyase decreased. These results indicated that EC does not have any potential to be considered as resistance inducers against sclerotinia carrot rot. PMID:26821652

  12. Garlic exerts allelopathic effects on pepper physiology in a hydroponic co-culture system.

    Science.gov (United States)

    Ding, Haiyan; Cheng, Zhihui; Liu, Menglong; Hayat, Sikandar; Feng, Han

    2016-01-01

    A hydroponic co-culture system was adopted to determine the allelopathic potential of garlic on the growth of pepper plants. Different numbers of garlic plants (0, 2, 4, 8 and 12) were hydroponically co-cultured with two pepper plants to investigate allelopathic effects on the growth attributes and antioxidative defense system of the test pepper plants. The responses of the pepper plants depended on the number of garlic plants included in the co-culture system, indicating an association of pepper growth with the garlic root exudate concentration. When grown at a pepper/garlic ratio of 1:1 or 1:2, the pepper plant height, chlorophyll content, and peroxidase (POD), catalase (CAT) and phenylalanine ammonia-lyase (PAL) activities were significantly increased after 30 days of co-culture; in contrast, reduction in methane dicarboxylic aldehyde (MDA) content was observed. However, when the pepper/garlic ratio was 1:4 or higher, these morphological indices and protective enzyme activities were significantly inhibited, whereas MDA levels in the pepper leaves were significantly increased due to severe membrane lipid peroxidation. The results indicate that although low concentrations of garlic root exudates appear to induce protective enzyme systems and promote pepper growth, high concentrations have deleterious effects. These findings suggest that further investigations should optimize the co-culture pepper/garlic ratio to reduce continuous cropping obstacles in pepper production. PMID:27095440

  13. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-01-01

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the −Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from −Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the −Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the −Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in −Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively. PMID:27091552

  14. Water stress induces changes in polyphenol profile and antioxidant capacity in poplar plants (Populus spp.).

    Science.gov (United States)

    Popović, B M; Štajner, D; Ždero-Pavlović, R; Tumbas-Šaponjac, V; Čanadanović-Brunet, J; Orlović, S

    2016-08-01

    This paper is aimed to characterize young poplar plants under the influence of water stress provoked by polyethileneglycol 6000 (PEG 6000). Three polar genotypes (M1, B229, and PE19/66) were grown in hydroponics and subjected to 100 and 200 mOsm PEG 6000 during six days. Polyphenol characterization, two enzymatic markers and antioxidant capacity in leaves and roots were investigated in stressed plants. Total phenol content, ferric reducing antioxidant capacity (FRAP) and DPPH antiradical power (DPPH ARP) were determined for estimating total antioxidant capacity. Polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) were determined as enzymatic markers. Polyphenol characterization of poplar samples was performed by HPLC-PDA analysis. All results were subjected to correlation analysis and principal component analysis (PCA). Inspite of the decrease of total phenol content in investigated genotypes, as well as total antioxidant capacity, some of polyphenols were affected by stress like flavonoids chrysin, myricetine, kaempferol and isoferulic acid in roots of B229 genotype (Populus deltoides). Genotype B229 also showed the increase of antioxidant capacity and PAL activity in root and leaves under stress what could be the indicator of the adaptability of poplar plants to water stress. Significant positive correlations were obtained between PAL, antioxidant capacity as well as phenolic acids among themselves. Chemometric evaluation showed close interdependence between flavonoids, FRAP, DPPH antiradical power and both investigated enzymes of polyphenol metabolism, PAL and PPO. PMID:27116372

  15. The Effect and Action Mechanisms of Oligochitosan on Control of Stem Dry Rot of Zanthoxylum bungeanum.

    Science.gov (United States)

    Li, Peiqin; Cao, Zhimin; Wu, Zhou; Wang, Xing; Li, Xiuhong

    2016-01-01

    In this report, the effects of two oligochitosans, i.e., oligochitosan A (OCHA) and oligochitosan B (OCHB), on control of dry rot of Zanthoxylum bungeanum (Z. bungeanum) caused by Fusarium sambucinum (F. sambucinum) were evaluated. First, both oligochitosans show desirable ability to decrease the infection of F. sambucinum. Second, the oligochitosans strongly inhibit the radial colony and submerged biomass growth of F. sambucinum. Lastly, these oligochitosans are capable of increasing the activities of phenylalanine ammonia lyase (PAL), polyphenoloxidase (PPO) and peroxidase (POD) significantly, as well as enhancing the content of total phenolics in Z. bungeanum stems. These findings indicate that the protective effects of OCHA and OCHB on Z. bungeanum stems against dry rot may be associated with the direct fungitoxic function against pathogen and the elicitation of biochemical defensive responses in Z. bungeanum stems. The outcome of this report suggests that oligochitosans may serve as a promising natural fungicide to substitute, at least partially, for synthetic fungicides in the disease management of Z. bungeanum. PMID:27376270

  16. The Effect and Action Mechanisms of Oligochitosan on Control of Stem Dry Rot of Zanthoxylum bungeanum

    Directory of Open Access Journals (Sweden)

    Peiqin Li

    2016-06-01

    Full Text Available In this report, the effects of two oligochitosans, i.e., oligochitosan A (OCHA and oligochitosan B (OCHB, on control of dry rot of Zanthoxylum bungeanum (Z. bungeanum caused by Fusarium sambucinum (F. sambucinum were evaluated. First, both oligochitosans show desirable ability to decrease the infection of F. sambucinum. Second, the oligochitosans strongly inhibit the radial colony and submerged biomass growth of F. sambucinum. Lastly, these oligochitosans are capable of increasing the activities of phenylalanine ammonia lyase (PAL, polyphenoloxidase (PPO and peroxidase (POD significantly, as well as enhancing the content of total phenolics in Z. bungeanum stems. These findings indicate that the protective effects of OCHA and OCHB on Z. bungeanum stems against dry rot may be associated with the direct fungitoxic function against pathogen and the elicitation of biochemical defensive responses in Z. bungeanum stems. The outcome of this report suggests that oligochitosans may serve as a promising natural fungicide to substitute, at least partially, for synthetic fungicides in the disease management of Z. bungeanum.

  17. Metabolic changes in carrot cells in response to simultaneous treatment with ultraviolet light and a fungal elicitor

    International Nuclear Information System (INIS)

    Ultraviolet light induces anthocyanin biosynthesis in cell cultures of an Afghan cultivar of Daucus carota (Daucus carota L. ssp. sativus). Simultaneous treatment with a fungal elicitor from Pythium aphanidermatum results in an inhibition of the catalytic activity of chalcone synthase (CHS), which in turn correlates with an inhibition of anthocyanin biosynthesis. On immunoblots, one isoenzyme (40 kDa) of CHS disappears upon elicitor treatment. On an mRNA level, only the mRNA for the 40-kDa-CHS is active after treatment with ultraviolet light. After inhibition of anthocyanin biosynthesis by the elicitor the enzyme protein disappears and the CHS mRNA is strongly diminished. This inhibition depends on the concentration of the elicitor. In addition, elicitor treatment leads to an induction of the general phenylpropanoid pathway as well as to the accumulation of 4-hydroxybenzoic acid which is covalently bound to wall polysaccharides of the carrot cells. The possible function of phenylalanine ammonia-lyase in providing precursors for 4-hydroxybenzoic acid is discussed

  18. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice.

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-01-01

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the -Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from -Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the -Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the -Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in -Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively. PMID:27091552

  19. Chitosan and oligochitosan enhance ginger (Zingiber officinale Roscoe) resistance to rhizome rot caused by Fusarium oxysporum in storage.

    Science.gov (United States)

    Liu, Yiqing; Wisniewski, Michael; Kennedy, John F; Jiang, Yusong; Tang, Jianmin; Liu, Jia

    2016-10-20

    The ability of chitosan and oligochitosan to enhance ginger (Zingiber officinale) resistance to rhizome rot caused by Fusarium oxysporum in storage was investigated. Both chitosan and oligochitosan at 1 and 5g/L significantly inhibited rhizome rot, with the best control at 5g/L. Chitosan and oligochitosan applied at 5g/L also reduced weight loss, measured as a decrease in fresh weight, but did not affect soluble solids content or titratable acidity of rhizomes. The two compounds applied at 5g/L induced β-1,3-glucanase and phenylalanine ammonia-lyase enzyme activity and the transcript levels of their coding genes, as well as the total phenolic compounds in rhizome tissues. Therefore, the ability of chitosan and oligochitosan to reduce rot in stored rhizomes may be associated with their ability to induce defense responses in ginger. These results have practical implications for the application of chitosan and oligochitosan to harvested ginger rhizomes to reduce postharvest losses. PMID:27474591

  20. Generation of pea mutants for resistance to Ascochyta blight and powdery mildew and their characterization using isozyme markers [Pisum sativum L.; India

    International Nuclear Information System (INIS)

    To induce resistance in pea against Ascochyta blight and powdery mildew through mutagenesis, two locally grown cultivars Lincoln and Palam Priya were subjected to three doses each of gamma rays (10, 15 and 20 kR) and chemical mutagen ethylmethane sulfonate (0.1, 0.2 and 0.3%). Reduced germination was observed in response to mutagen treatment in both cultivars. Phenotypic changes were observed in M1 and M2 generations of both the cultivars. In M2 generation twenty-seven mutants of Lincoln and sixteen of Palam Priya were found resistant to Ascochyta blight under natural epiphytotic conditions. High level of resistance in M2 generation against powdery mildew could not be achieved. Plant progenies in the M3 generation were also evaluated for resistance to Ascochyta pinodes as well as Erysiphe pisi through detached leaf technique. Six mutants of Lincoln and only one of Palam Priya were found resistant to A. pinodes. One mutant of Palam Priya (P15-3) showed resistance to both the pathogens. Increased phenylalanine ammonia lyase activity was observed in all the resistant mutants. New isoforms of peroxidase could be detected in the mutant P15-3 (Palam Priya) and also in L0.2-1 (Lincoln). However, not much variation for esterase could be observed

  1. Early Phenylpropanoid Biosynthetic Steps in Cannabis sativa: Link between Genes and Metabolites

    Directory of Open Access Journals (Sweden)

    Immacolata Coraggio

    2013-06-01

    Full Text Available Phenylalanine ammonia-lyase (PAL, Cinnamic acid 4-hydroxylase (C4H and 4-Coumarate: CoA ligase (4CL catalyze the first three steps of the general phenylpropanoid pathway whereas chalcone synthase (CHS catalyzes the first specific step towards flavonoids production. This class of specialized metabolites has a wide range of biological functions in plant development and defence and a broad spectrum of therapeutic activities for human health. In this study, we report the isolation of hemp PAL and 4CL cDNA and genomic clones. Through in silico analysis of their deduced amino acid sequences, more than an 80% identity with homologues genes of other plants was shown and phylogenetic relationships were highlighted. Quantitative expression analysis of the four above mentioned genes, PAL and 4CL enzymatic activities, lignin content and NMR metabolite fingerprinting in different Cannabis sativa tissues were evaluated. Furthermore, the use of different substrates to assay PAL and 4CL enzymatic activities indicated that different isoforms were active in different tissues. The diversity in secondary metabolites content observed in leaves (mainly flavonoids and roots (mainly lignin was discussed in relation to gene expression and enzymatic activities data.

  2. The biosynthesis of salicylic acid in potato plants

    International Nuclear Information System (INIS)

    Spraying potato (Solanum tuberosum L.) leaves with arachidonic acid (AA) at 1500 micrograms mL-1 led to a rapid local synthesis of salicylic acid (SA) and accumulation of a SA conjugate, which was shown to be 2-O-beta-glucopyranosylsalicylic acid. Radiolabeling studies with untreated leaves showed that SA was synthesized from phenylalanine and that both cinnamic and benzoic acid were intermediates in the biosynthesis pathway. Using radiolabeled phenylalanine as a precursor, the specific activity of SA was found to be lower when leaves were treated with AA than in control leaves. Similar results were obtained when leaves were fed with the labeled putative intermediates cinnamic acid and benzoic acid. Application of 2-aminoindan-2-phosphonic acid at 40 micromolar, an inhibitor of phenylalanine ammonia-lyase, prior to treatment with AA inhibited the local accumulation of SA. When the putative intermediates were applied to leaves in the presence of 2-aminoindan-2-phosphonic acid, about 40% of the expected accumulation of free SA was recovered, but the amount of the conjugate remained constant

  3. Bismerthiazol Inhibits Xanthomonas citri subsp. citri Growth and Induces Differential Expression of Citrus Defense-Related Genes.

    Science.gov (United States)

    Yu, Xiaoyue; Armstrong, Cheryl M; Zhou, Mingguo; Duan, Yongping

    2016-07-01

    Citrus canker, caused by Xanthomonas citri ssp. citri, is a serious disease that causes substantial economic losses to the citrus industry worldwide. The bactericide bismerthiazol has been used to control rice bacterial blight (X. oryzae pv. oryzae). In this paper, we demonstrate that bismerthiazol can effectively control citrus canker by both inhibiting the growth of X. citri ssp. citri and triggering the plant's host defense response through the expression of several pathogenesis-related genes (PR1, PR2, CHI, and RpRd1) and the nonexpresser of PR genes (NPR1, NPR2, and NPR3) in 'Duncan' grapefruit, especially at early treatment times. In addition, we found that bismerthiazol induced the expression of the marker genes CitCHS and CitCHI in the flavonoid pathway and the PAL1 (phenylalanine ammonia lyase 1) gene in the salicylic acid (SA) biosynthesis pathway at different time points. Moreover, bismerthiazol also induced the expression of the priming defense-associated gene AZI1. Taken together, these results indicate that the induction of the defense response in 'Duncan' grapefruit by bismerthiazol may involve the SA signaling pathway and the priming defense and that bismerthiazol may serve as an alternative to copper bactericides for the control of citrus canker. PMID:26882850

  4. Postharvest Exogenous Application of Abscisic Acid Reduces Internal Browning in Pineapple.

    Science.gov (United States)

    Zhang, Qin; Liu, Yulong; He, Congcong; Zhu, Shijiang

    2015-06-10

    Internal browning (IB) is a postharvest physiological disorder causing economic losses in pineapple, but there is no effective control measure. In this study, postharvest application of 380 μM abscisic acid (ABA) reduced IB incidence by 23.4-86.3% and maintained quality in pineapple fruit. ABA reduced phenolic contents and polyphenol oxidase and phenylalanine ammonia lyase activities; increased catalase and peroxidase activities; and decreased O2(·-), H2O2, and malondialdehyde levels. This suggests ABA could control IB through inhibiting phenolics biosynthesis and oxidation and enhancing antioxidant capability. Furthermore, the efficacy of IB control by ABA was not obviously affected by tungstate, ABA biosynthesis inhibitor, nor by diphenylene iodonium, NADPH oxidase inhibitor, nor by lanthanum chloride, calcium channel blocker, suggesting that ABA is sufficient for controlling IB. This process might not involve H2O2 generation, but could involve the Ca(2+) channels activation. These results provide potential for developing effective measures for controlling IB in pineapple. PMID:26007196

  5. Defense Responses in Rice Induced by Silicon Amendment against Infestation by the Leaf Folder Cnaphalocrocis medinalis.

    Science.gov (United States)

    Han, Yongqiang; Li, Pei; Gong, Shaolong; Yang, Lang; Wen, Lizhang; Hou, Maolin

    2016-01-01

    Silicon (Si) amendment to plants can confer enhanced resistance to herbivores. In the present study, the physiological and cytological mechanisms underlying the enhanced resistance of plants with Si addition were investigated for one of the most destructive rice pests in Asian countries, the rice leaf folder, Cnaphalocrocis medinalis (Guenée). Activities of defense-related enzymes, superoxide dismutase, peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase, and concentrations of malondialdehyde and soluble protein in leaves were measured in rice plants with or without leaf folder infestation and with or without Si amendment at 0.32 g Si/kg soil. Silicon amendment significantly reduced leaf folder larval survival. Silicon addition alone did not change activities of defense-related enzymes and malondialdehyde concentration in rice leaves. With leaf folder infestation, activities of the defense-related enzymes increased and malondialdehyde concentration decreased in plants amended with Si. Soluble protein content increased with Si addition when the plants were not infested, but was reduced more in the infested plants with Si amendment than in those without Si addition. Regardless of leaf folder infestation, Si amendment significantly increased leaf Si content through increases in the number and width of silica cells. Our results show that Si addition enhances rice resistance to the leaf folder through priming the feeding stress defense system, reduction in soluble protein content and cell silicification of rice leaves. PMID:27124300

  6. Defence strategies adopted by the medicinal plant Coleus forskohlii against supplemental ultraviolet-B radiation: Augmentation of secondary metabolites and antioxidants.

    Science.gov (United States)

    Takshak, Swabha; Agrawal, S B

    2015-12-01

    Supplementary ultraviolet-B (ambient+3.6  kJ m(-2) day(-1)) induced changes on morphological, physiological, and biochemical characteristics (specifically the defence strategies: UV-B protective compounds and antioxidants) of Coleus forskohlii were investigated under field conditions at 30, 60, and 90 days after transplantation. Levels of secondary metabolites increased under s-UV-B stress; flavonoids and phenolics (primary UV-B screening agents) were recorded to be higher in leaves which are directly exposed to s-UV-B. This was also verified by enhanced activities of phenylpropanoid pathway enzymes: phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), 4-coumarate-CoA ligase (4CL), chalcone-flavanone isomerase (CHI), and dihydroflavonol reductase (DFR). Antioxidants, both enzymatic (ascorbate peroxidase, catalase, glutathione reductase, peroxidase, polyphenol oxidase, and superoxide dismutase) and non-enzymatic (ascorbic acid and α-tocopherol) also increased in the treated organs of the test plant, higher contents being recorded in roots except for ascorbic acid. On the contrary, protein and chlorophyll content (directly implicated in regulating plant growth and development) declined under s-UV-B. These alterations in plant biochemistry led the plant to compromise on its photosynthate allocation towards growth and biomass production as evidenced by a reduction in its height and biomass. The study concludes that s-UV-B is a potent stimulating factor in increasing the concentrations of defense compounds and antioxidants in C. forskohlii to optimize its performance under stress. PMID:26461242

  7. Comparative study on the induction of defense related enzymes in two different cultivars of chickpea (Cicer arietinum L genotypes by salicylic acid, spermine and Fusarium oxysporum f. sp. ciceri

    Directory of Open Access Journals (Sweden)

    S. Raju

    2008-11-01

    Full Text Available Induction of some defense related enzymes and phenolics in roots and shoots of two different genotypes of chickpea cultivars which were susceptible (L550 and resistant (ICCV10 to wilt disease treated with salicylic acid, spermine (Spm, SA+Spm and Fusarium oxysporum f. sp. ciceri was investigated. Higher levels of polyphenol oxidase (PPO, phenylalanine ammonia-lyase (PAL, ß-1, 3-glucanase (PR-2 and phenolics were observed in roots and shoots of resistant cultivar than that of susceptible cultivar on treatment with elicitors and pathogen. However, no major changes were observed in susceptible cultivar after the treatments. ß-1, 3-glucanase is constitutively present and is further induced in roots and shoots of resistant cultivar by F. oxysporum f. sp. ciceri. No induction of ß-1, 3-glucanase was observed in susceptible cultivar. The structural changes during disease progression were observed by histochemical staining. However, the pathogen invasion was more in susceptible cultivar compared with resistant cultivar. Further, the invasion was restricted in roots of resistant cultivar treated with SA. These results suggest that induction of defense proteins and accumulation of phenolics might have contributed to restrict the invasion of F.oxysporum f. sp. ciceri, in resistant cultivar ICCV10.

  8. Flavonol Glucoside and Antioxidant Enzyme Biosynthesis Affected by Mycorrhizal Fungi in Various Cultivars of Onion (Allium cepa L.).

    Science.gov (United States)

    Mollavali, Mohanna; Bolandnazar, Saheb Ali; Schwarz, Dietmar; Rohn, Sascha; Riehle, Peer; Zaare Nahandi, Fariborz

    2016-01-13

    The objective of this study was to investigate the impact of mycorrhizal symbiosis on qualitative characteristics of onion (Allium cepa L.). For this reason, five onion cultivars with different scale color and three different strains of arbuscular mycorrhizal fungi (Diversispora versiformis, Rhizophagus intraradices, Funneliformis mosseae) were used. Red cultivars, mainly 'Red Azar-shahr', showed the highest content in vitamin C, flavonols, and antioxidant enzymes. Mycorrhizal inoculation increased total phenolic, pyruvic acid, and vitamin C of onion plants. Considerable increase was observed in quercetin-4'-O-monoglucoside and isorhamnetin-4'-O-monoglucoside content in plants inoculated with Diversispora versiformis, but quercetin-3,4'-O-diglucoside was not significantly influenced. Analyses for phenylalanine ammonia-lyase (PAL) and antioxiodant enzyme activities such as polyphenol oxidase (PPO), catalase (CAT), and peroxidase (POD) revealed that all except PPO were enhanced by mycorrhizal inoculation. Overall, these findings suggested that mycorrhizal inoculation influenced biosynthesis of flavonol glucosides and antioxidant enzymes by increasing nutrient uptake or by induction of the plant defense system. PMID:26694086

  9. Salicylic acid and heat acclimation pretreatment protects Laminaria japonica sporophyte (Phaeophyceae) from heat stress

    Science.gov (United States)

    Zhou, Bin; Tang, Xuexi; Wang, You

    2010-07-01

    Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica (Phaeophyceae) from heat stress were studied. Heat stress resulted in oxidative injury in the kelp blades. Under heat stress significant accumulation of hydrogen peroxide (H2O2) and malonaldehyde (MDA), a membrane lipid peroxidation product, and a drastic decrease in chlorophyll a content were recorded. Activity of the enzymatic antioxidant system was drastically affected by heat stress. The activity of superoxide dismutase (SOD) was significantly increased while peroxidase (POD), catalase (CAT) and glutathione peroxidase (GPX) were greatly inhibited and, simultaneously, phenylalanine ammonia-lyase was activated while polyphenol oxidase (PPO) was inhibited. Both heat acclimation pretreatment and exogenous application of salicylic acid alleviated oxidative damage in kelp blades. Blades receiving heat acclimation pretreatment and exogenous salicylic acid prior to heat stress exhibited a reduced increase in H2O2 and MDA content, and a lower reduction in chlorophyll a content. Pretreatment with heat acclimation and salicylic acid elevated activities of SOD, POD, CAT, GPX and PPO. Considering these results collectively, we speculate that the inhibition of antioxidant enzymes is a possible cause of the heat-stress-induced oxidative stress in L. japonica, and enhanced thermotolerance may be associated, at least in part, with the elevated activity of the enzymatic antioxidant system.

  10. Hydrogen sulfide prolongs postharvest storage of fresh-cut pears (Pyrus pyrifolia by alleviation of oxidative damage and inhibition of fungal growth.

    Directory of Open Access Journals (Sweden)

    Kang-Di Hu

    Full Text Available Hydrogen sulfide (H2S has proved to be a multifunctional signaling molecule in plants and animals. Here, we investigated the role of H2S in the decay of fresh-cut pears (Pyrus pyrifolia. H2S gas released by sodium hydrosulfide (NaHS prolonged the shelf life of fresh-cut pear slices in a dose-dependent manner. Moreover, H2S maintained higher levels of reducing sugar and soluble protein in pear slices. H2S significantly reduced the accumulation of hydrogen peroxide (H2O2, superoxide radicals (•O2(- and malondialdehyde (MDA. Further investigation showed that H2S fumigation up-regulated the activities of antioxidant enzymes ascorbate peroxidase (APX, catalase (CAT, and guaiacol peroxidase (POD, while it down-regulated those of lipoxygenase (LOX, phenylalanine ammonia lyase (PAL and polyphenol oxidase (PPO. Furthermore, H2S fumigation effectively inhibited the growth of two fungal pathogens of pear, Aspergillus niger and Penicillium expansum, suggesting that H2S can be developed as an effective fungicide for postharvest storage. The present study implies that H2S is involved in prolonging postharvest storage of pears by acting as an antioxidant and fungicide.

  11. Effect of amino acid application on induced resistance against citrus canker disease in lime plants

    Directory of Open Access Journals (Sweden)

    Hasabi Vahideh

    2014-07-01

    Full Text Available Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc, is a destructive disease. So far, the chemicals used to control this pathogen are either ineffective or harmful to the environment. To improve control of this disease, lime (Citrus aurantifolia were treated with L-arginine, L-methionine, L-ornithine, and distilled water. Plants were inoculated with Xcc, 48 hours post treatment. Lesion diameters of inoculated leaves were evaluated four weeks after inoculation with a bacterial suspension. Changes in β-1,3-glucanase transcript levels and activity of antioxidant enzymes, catalase, peroxidase, and phenylalanine ammonia-lyase were investigated at 48 hours post treatment and 24, 48, and 72 hours post inoculation. Based on the results of phenotypic, antioxidant enzyme activity and a molecular study of the stressed plants, it was found that those plants treated with the amino acid methionine significantly increased the plant induced resistance as well as decreased the severity of disease by reducing necrotic lesion size.

  12. Microscopic and biochemical evidence of differentially virulent field isolates of Diplocarpon rosae causing black spot disease of roses.

    Science.gov (United States)

    Gachomo, Emma W; Kotchoni, Simeon O

    2010-01-01

    Black spot disease caused by Diplocarpon rosae is one of the most widespread diseases of roses that are very difficult to control due to the generative reproduction and complex genetic constitution of roses and up to now the control of black spot still requires intensive use of systemic fungicides. Here we report for the first time evidence of differentially virulent field isolates of D. rosae. Using a combination of fungal structures, disease symptoms and host cells protein expression pattern analysis we here provide direct biochemical evidence that tropical field isolates of D. rosae are more virulent and caused disease symptoms earlier than their temperate counterparts. The tropical fungal field isolates strongly induced an excessive accumulation of ROS and repressed activity of pathogenesis-related proteins such as peroxidases, chitinase and phenylalanine ammonia lyase compared to their temperate counterparts. These findings bring insights into a hidden pathogenic characteristic of tropical D. rosae field isolates compared to their temperate counterparts and open a novel dimension of parameters to be considered when controlling black spot disease of roses by fungicides in tropical versus temperate regions. Interestingly, we found that treatment of rose leaves with ROS (H2O2) prior to fungal inoculation promoted plant defense response regardless of the isolate virulence based on protein expression pattern analysis, suggesting that ROS (H2O2) can be efficiently incorporated into black spot disease management. PMID:20137960

  13. Effect of pyrogallol on the physiology and biochemistry of litchi fruit during storage

    Directory of Open Access Journals (Sweden)

    Jing Guoxing

    2013-01-01

    Full Text Available Abstract Background Litchi (Litchi chinensis Sonn. fruit are highly perishable and have a very short shelf life, easily turning brown and decaying. This study investigated the efficiency of pyrogallol, a catechin on the physiology and biochemistry in relation to storage life of litchi fruit. Results Fruit were treated with pyrogallol at 1 mM and then stored at ambient temperature (25°C or low temperature (4°C. Compared with control, pyrogallol significantly reduced pericarp browning and delayed the rotting of fruit day 4 at 25°C, and on day 30 at 4°C. The chemical treatment reduced respiration rate and the activities of peroxidase (POD and polyphenol oxidase (PPO, and delayed the loss of membrane permeability. Pyrogallol increased the activity of phenylalanine ammonia-lyase (PAL, delayed the loss of anthocyanin and phenolics, and maintained high 2,2-diphenyl-1-picrlhydrazyl (DPPH radical scavenging activity and reducing power. High performance liquid chromatograph (HPLC analysis clearly indicated that treated fruit contained higher concentration of the four phenolic compounds procyanidin B1, (+-catechin, (−-epicatechin and (−-epicatechin-3-gallate. Conclusions The application of pyrogallol partially reducing pericarp browning and changed quality-related physiological activities and, thus, pyrogallol could have beneficial effects on pericarp browning and fruit decay control, and could be helpful for litchi fruit postharvest storage.

  14. Identification of reference genes suitable for qRT-PCR in grapevine and application for the study of the expression of genes involved in pterostilbene synthesis.

    Science.gov (United States)

    Gamm, Magdalena; Héloir, Marie-Claire; Kelloniemi, Jani; Poinssot, Benoît; Wendehenne, David; Adrian, Marielle

    2011-04-01

    The recent publication of the grapevine genome sequence facilitates the use of qRT-PCR to study gene expression changes. For this approach, reference genes are commonly used to normalize data and their stability of expression should be systematically validated. Among grapevine defenses is the production of the antimicrobial stilbenic phytoalexins, notably the highly fungitoxic pterostilbene, which plays a crucial role in grapevine interaction with Plasmopara viticola and Botrytis cinerea. As a resveratrol O-methyltransferase (ROMT) gene involved in pterostilbene synthesis was recently identified, we investigated the accumulation of the corresponding transcripts to those of two other stilbene biosynthesis related genes phenylalanine ammonia lyase (PAL) and stilbene synthase (STS) in response to pathogen infection. Using three computer-based statistical methods and C(t) values or LRE method generated values as input data, we have first identified two reference genes (VATP16 and 60SRP) suitable for normalization of qPCR expression data obtained in grapevine leaves and berries infected by P. viticola and B. cinerea, respectively. Next, we have highlighted that the expression of ROMT is induced in P. viticola-infected leaves and also in B. cinerea-infected berries, confirming the involvement of pterostilbene in grapevine defenses. PMID:21340517

  15. Stress stimulus induced resistance to Cladosporium cucumerinum in cucumber seeding.

    Science.gov (United States)

    Zhao, Huan; Wang, Bo-Chu; Zhao, Hu-Cheng; Wang, Jing Bo

    2005-07-25

    Up to date, the studies of plant induced resistance have become the focus in plant pathology and physiology. During the course of pathogens penetrating the plant cell, besides of chemical secretion, the pathogens may generate mechanical signal caused by the physical pressure on the plant cell. In the non-host resistance, both the chemical signal and the mechanical stress signal are considered to have contribution to the entire defense reaction acted by the plant. The penetration of pathogen Cladosporium cucumerinum to cucumber is thought to be one of the model in research of plant induced resistance. In the current study, as a mechanical signal elicitor, the appropriate stress stimulus was proved to effectually induce the resistance of cucumber seedling to C. cucumerinum. After the treatment of the stress stimulus on leaves, the activities of resistance-related enzymes were significantly increased, such as phenylanine ammonia lyase (PAL), peroxidase (POD). Also, we found that stress stimulation may cause synthesis of lignin, which acts as the physical barrier to defense the pathogens. The results suggest that stress stimulation may not only enhance ability of the plant cell resistance to pathogen penetration but also elicit the accumulation of pathogens suppression or antimicrobial chemical substance in the plant cell. PMID:16002268

  16. Gene regulation of anthocyanin biosynthesis in two blood-flesh peach (Prunus persica (L.) Batsch) cultivars during fruit development.

    Science.gov (United States)

    Jiao, Yun; Ma, Rui-juan; Shen, Zhi-jun; Yan, Juan; Yu, Ming-liang

    2014-09-01

    The blood-flesh peach has become popular in China due to its attractive anthocyanin-induced pigmentation and antioxidant properties. In this study, we investigated the molecular mechanisms underlying anthocyanin accumulation by examining the expression of nine genes of the anthocyanin biosynthesis pathway found in the peach mesocarp. Expression was measured at six developmental stages in fruit of two blood-flesh and one white-flesh peach cultivars, using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results show that the expression of the chalcone synthase (CHS) gene was closely related to anthocyanin accumulation in both of the blood-flesh peaches. In the white-flesh peach, we found that the transcription level of phenylalanine ammonia-lyase (PAL) during fruit development was much lower than that in the blood-flesh peach, even though all other genes of the anthocyanin biosynthesis pathway were highly expressed, suggesting that the PAL gene may be limiting in anthocyanin production in the white-flesh peach. Moreover, the transcription levels of the CHS and UDP-glucose-flavonoid 3-O-glucosyltransferase (UFGT) genes were markedly up-regulated at three days after bag removal (DABR) in the blood-flesh peach, suggesting that CHS and UFGT are the key genes in the process of anthocyanin biosynthesis for both of the blood-flesh peaches. The present study will be of great help in improving understanding of the molecular mechanisms involved in anthocyanin accumulation in blood-flesh peaches. PMID:25183035

  17. Association of lignifying enzymes in shell synthesis of oil palm fruit (Elaeis guineensis--dura variety).

    Science.gov (United States)

    Bhasker, S; Mohankumar, C

    2001-02-01

    Scanning electron microscopic (SEM) observation demonstrates the differentiation of mesocarp and endocarp tissues and their lignified nature in dura fruits at 8 weeks after pollination (WAP). During shell formation, the endocarp cells become lignified to a hard shell while the mesocarp tissue remains cellular and fibrous. A transition zone made up of fibrous units was also visible beneath the shell. The soluble phenols of mesocarp and endocarp tissues at their developmental stage was analyzed using Reverse phase high performance liquid chromatography (RP-HPLC). The appearance of ferulic acid at 4 WAP and its absence at 8 WAP indicates the role of ferulic acid in lignin synthesis. The HPLC data was supported by the lignin concentration. To ascertain the biochemical relationship of lignin pathway enzymes, phenylalanine ammonia lyase (PAL), cinnamyl alcohol-NADPH-dehydrogenase (CAD) and peroxidase (POD) with shell synthesis, the activities of these enzymes and lignin content were assessed during development of the shell between 4 and 8 WAP. The three enzymes, PAL, CAD and POD expressed high level of activity in the mesocarp and endocarp at 4 WAP. At 8 WAP a sharp decline in activity was observed in the endocarp whereas the mesocarp showed a moderate reduction. This variation is an indication of the role of these enzymes in shell formation. PMID:11480213

  18. Effects of modified atmosphere package on physiological characteristics of daemonorops margaritae shoots during storage%气调包装对黄藤笋贮藏期间生理特性的影响

    Institute of Scientific and Technical Information of China (English)

    刘晓蓉

    2011-01-01

    研究体积分数为3%O2、5%CO 2和92%N2的气调处理和不同贮藏温度对黄藤笋生理特性的影响.黄藤笋经气调处理后,分别于8℃和20℃下贮藏,定期测定其褐变度(BD)、呼吸强度、苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)和过氧化氢酶(CAT)活性等生理指标.结果表明,气调处理结合8℃的低温贮藏,能显著降低黄藤笋的呼吸强度,抑制PAL、POD和PPO活性的上升,保持CAT的活性,延缓褐变的发生,延长保质期.%At different temperature, the effects were studied of modified atmosphere package (MAP) (3% O2 、5% CO2 and 92% N2)on physiological characteristics of daemonorops margaritae shoots. Daemonorops margaritae shoots with controlled atmosphere storage were stored at 8 ℃ and 20 ℃. The changes were determined of browning degree, respiration rate, the activities of phenylalanine ammonia-lyase (PAL), peroxidase(POD), polyphenol oxidase (PPO) and catalase (CAT). The results showed that modified atmosphere package and low temperature(8 ℃) could reduce respiration rate, inhibit the increase of PAL, POD and PPO activity, maintain the activity of CAT, resist browning and prolong the shelf life of daemonorops margaritae shoots.

  19. Co-Treatment of EFF and 1-MCP for Enhancing the Shelf-Life and Aroma Volatile Compounds of Oriental Sweet Melons (Cucumis melo var. makuwa Makino)

    Institute of Scientific and Technical Information of China (English)

    BAI Xiao-hang; TENG Lu-hua; LÜ De-qing; QI Hong-yan

    2014-01-01

    Compared to other melon types, oriental sweet melon (Cucumis melo var. makuwa Makino) is quite a different species with a shorter shelf-life due to its typical climacteric behavior and thin pericarp. The purpose of this experiment is to explore the effects of co-treatment of enhanced freshness formulation (EFF) and 1-methylcyclopropene (1-MCP) on physiological changes and the content of aroma volatile compounds introduced by them of two oriental sweet melon cultivars (Yumeiren and Tianbao) during storage. The melons were stored in incubators with temperature of 15°C and a relative humidity of 85%for 24 d during which fruit quality and related physiological index were measured. Compared to the control, both treatments delayed fruit weight loss rate and kept the fruit ifrmness, water content and soluble solids content. Ascorbate peroxidase (APX) and phenylalanine ammonia lyase (PAL) activities showed lfuctuations in treated melons, while lipoxygenase (LOX) activity (P<0.01) and malondialdehyde (MDA) content (P<0.05) decreased compared to control. During the early stage of storage, alcohols and aldehydes were the main volatile compounds, and esters gradually increased during storage. Of all the esters, acetic esters were the main components, followed by oxalic acid esters and other esters. The total content of aroma volatile compounds, esters, alcohols and aldehydes of co-treated melons were all higher than those of 1-MCP treated and control melons. In addition, the aroma volatile peak of co-treated melons occurred later than that of 1-MCP treated and control melons. In summary, co-treatment of EFF and 1-MCP was more beneifcial than 1-MCP treatment to delay ripening and senescence, maintain fruit quality, enhance shelf-life and improve levels of aroma volatile compounds.

  20. Neonicotinoid insecticides alter induced defenses and increase susceptibility to spider mites in distantly related crop plants.

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    Adrianna Szczepaniec

    Full Text Available BACKGROUND: Chemical suppression of arthropod herbivores is the most common approach to plant protection. Insecticides, however, can cause unintended, adverse consequences for non-target organisms. Previous studies focused on the effects of pesticides on target and non-target pests, predatory arthropods, and concomitant ecological disruptions. Little research, however, has focused on the direct effects of insecticides on plants. Here we demonstrate that applications of neonicotinoid insecticides, one of the most important insecticide classes worldwide, suppress expression of important plant defense genes, alter levels of phytohormones involved in plant defense, and decrease plant resistance to unsusceptible herbivores, spider mites Tetranychus urticae (Acari: Tetranychidae, in multiple, distantly related crop plants. METHODOLOGY/PRINCIPAL FINDINGS: Using cotton (Gossypium hirsutum, corn (Zea mays and tomato (Solanum lycopersicum plants, we show that transcription of phenylalanine ammonia lyase, coenzyme A ligase, trypsin protease inhibitor and chitinase are suppressed and concentrations of the phytohormone OPDA and salicylic acid were altered by neonicotinoid insecticides. Consequently, the population growth of spider mites increased from 30% to over 100% on neonicotinoid-treated plants in the greenhouse and by nearly 200% in the field experiment. CONCLUSIONS/SIGNIFICANCE: Our findings are important because applications of neonicotinoid insecticides have been associated with outbreaks of spider mites in several unrelated plant species. More importantly, this is the first study to document insecticide-mediated disruption of plant defenses and link it to increased population growth of a non-target herbivore. This study adds to growing evidence that bioactive agrochemicals can have unanticipated ecological effects and suggests that the direct effects of insecticides on plant defenses should be considered when the ecological costs of insecticides

  1. Suppression of Hydroxycinnamate Network Formation in Cell Walls of Rice Shoots Grown under Microgravity Conditions in Space.

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    Kazuyuki Wakabayashi

    Full Text Available Network structures created by hydroxycinnamate cross-links within the cell wall architecture of gramineous plants make the cell wall resistant to the gravitational force of the earth. In this study, the effects of microgravity on the formation of cell wall-bound hydroxycinnamates were examined using etiolated rice shoots simultaneously grown under artificial 1 g and microgravity conditions in the Cell Biology Experiment Facility on the International Space Station. Measurement of the mechanical properties of cell walls showed that shoot cell walls became stiff during the growth period and that microgravity suppressed this stiffening. Amounts of cell wall polysaccharides, cell wall-bound phenolic acids, and lignin in rice shoots increased as the shoot grew. Microgravity did not influence changes in the amounts of cell wall polysaccharides or phenolic acid monomers such as ferulic acid (FA and p-coumaric acid, but it suppressed increases in diferulic acid (DFA isomers and lignin. Activities of the enzymes phenylalanine ammonia-lyase (PAL and cell wall-bound peroxidase (CW-PRX in shoots also increased as the shoot grew. PAL activity in microgravity-grown shoots was almost comparable to that in artificial 1 g-grown shoots, while CW-PRX activity increased less in microgravity-grown shoots than in artificial 1 g-grown shoots. Furthermore, the increases in expression levels of some class III peroxidase genes were reduced under microgravity conditions. These results suggest that a microgravity environment modifies the expression levels of certain class III peroxidase genes in rice shoots, that the resultant reduction of CW-PRX activity may be involved in suppressing DFA formation and lignin polymerization, and that this suppression may cause a decrease in cross-linkages within the cell wall architecture. The reduction in intra-network structures may contribute to keeping the cell wall loose under microgravity conditions.

  2. Transgenic poplar expressing the pine GS1a show alterations in nitrogen homeostasis during drought.

    Science.gov (United States)

    Molina-Rueda, Juan Jesús; Kirby, Edward G

    2015-09-01

    Transgenic hybrid poplars engineered to express ectopically the heterologous pine cytosolic GS1a display a number of significant pleiotropic phenotypes including enhanced growth, enhanced nitrogen use efficiency, and resistance to drought stress. The present study was undertaken in order to assess mechanisms whereby ectopic expression of pine GS1a in transgenic poplars results in enhanced agronomic phenotypes. Microarray analysis using the Agilent Populus whole genome array has allowed identification of genes differentially expressed between wild type (WT) and GS transgenics in four tissues (sink leaves, source leaves, stems, and roots) under three growth conditions (well-watered, drought, and recovery). Analysis revealed that differentially expressed genes in functional categories related to nitrogen metabolism show a trend of significant down-regulation in GS poplars compared to the WT, including genes encoding nitrate and nitrite reductases. The down-regulation of these genes was verified using qPCR, and downstream effects were further tested using NR activity assays. Results suggest that higher glutamine levels in GS transgenics regulate nitrate uptake and reduction. Transcript levels of nitrogen-related genes in leaves, including GS/GOGAT cycle enzymes, aspartate aminotransferase, GABA shunt enzymes, photorespiration enzymes, asparagine synthetase, phenylalanine ammonia lyase, isocitrate dehydrogenase, and PII, were also assessed using qPCR revealing significant differences between GS poplars and the WT. Moreover, metabolites related to these differentially expressed genes showed alterations in levels, including higher levels of GABA, hydroxyproline, and putrescine in the GS transgenic. These alterations in nitrogen homeostasis offer insights into mechanisms accounting for drought tolerance observed in GS poplars. PMID:26113157

  3. The Effect of Hot Water Treatment on Quality of Mengzi Pomegranate in During Storage%采后热处理对蒙自石榴贮藏品质的影响

    Institute of Scientific and Technical Information of China (English)

    樊爱萍; 鲁丽香; 刘卫

    2014-01-01

    The aim of the study was to evaluate the effect of hot water treatments on physiological and quality change of pomegranate during storage at room temperature. Pomegranate was processed at hot water from 38℃ to 50℃ for 5 min to 15 min. The results showed that pomegranate processed by 38℃for 15 min exhibited a better quality than other treatments.After the hot water treatment at 38℃ for 15 min, the weight loss were reduced, the respiratory intensity ,cell membrane permeability and Peroxidase (POD) activities of pomegranate were restrained significantly, Furthermore, the Phenylalanine Ammonia Lyase (PAL) activity was enhanced. These results indicated that the senescence of pomegranate was delayed after hot water treatments at 38℃ for 15 min,which were propitious to prolonging the storage longevity and keeping the intrinsic flavour quality of pomegranate.%该篇探讨了热水处理对石榴采后常温贮藏期间主要生理和品质变化的影响。石榴经过38℃、45℃、50℃,5min、10min、15min 处理,结果表明,38℃,15min热水处理可有效提高好果率,降低失重率,较好的抑制石榴采后呼吸强度、质膜相对透性,降低过氧化物酶(POD)活性,提高苯丙氨酸解氨酶(PAL)活性。实验证明热处理能有效减缓石榴品质的下降,延缓石榴采后衰老速度,有利于延长贮藏期限和保持石榴原有的风味品质。

  4. 茉莉酸甲酯处理对鲜切莴苣和甘蓝苯丙烷代谢的影响%Effect of MeJA treatments on benzene propane metabolism in tissues of fresh-cut lettuce and cabbage

    Institute of Scientific and Technical Information of China (English)

    马杰; 胡文忠; 毕阳; 姜爱丽; 萨仁高娃

    2013-01-01

    Fresh - cut lettuce and cabbage were taken as experimental materials which treated with methyl 1jasmonate( MeJA) at 10μmol/L( 10% methanol as solvent), and the effect of the chemical on benzenebpropane metabolic in tissues of fresh - cut lettuce and cabbage were studied. The results showed that MeJA treatment increased PAL( phenylalanin ammonia - lyase) activity of fresh-cut lettuce and cabbage effectively, and also enhanced the content of total phenol,flavonoids and lignin.lt was considered that MeJA could be used as signal molecule to induce the synthesis of polyphenol of benzene propane metabolic pathway to enhance the repair ability by itself and the resistance of fresh-cut lettuce and cabbage.%本文以鲜切莴苣和鲜切甘蓝为实验材料,采用10μmol/L茉莉酸甲酯(以10%甲醇为溶剂)浸泡处理,研究了处理后鲜切莴苣和鲜切甘蓝苯丙烷代谢的变化.结果表明,MeJA处理可有效提高鲜切莴苣和鲜切甘蓝苯丙氨酸解氨酶(PAL)活性,同时,次生代谢产物如总酚、类黄酮以及木质素的含量也有所增加 由此可见,茉莉酸甲酯作为外界信号分子可诱导并激活苯丙烷代谢途径运行,合成多酚类化合物用以修复伤口,提高鲜切莴苣和甘蓝的自身修复能力与抗性.

  5. Abscisic Acid Induced Changes in Production of Primary and Secondary Metabolites, Photosynthetic Capacity, Antioxidant Capability, Antioxidant Enzymes and Lipoxygenase Inhibitory Activity of Orthosiphon stamineus Benth.

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    Mohd Hafiz Ibrahim

    2013-07-01

    Full Text Available An experiment was conducted to investigate and distinguish the relationships in the production of total phenolics, total flavonoids, soluble sugars, H2O2, O2−, phenylalanine ammonia lyase (PAL activity, leaf gas exchange, antioxidant activity, antioxidant enzyme activity [ascorbate peroxidase (APX, catalase (CAT, superoxide dismutase (SOD and Lipoxygenase inhibitory activity (LOX] under four levels of foliar abscisic acid (ABA application (0, 2, 4, 6 µM for 15 weeks in Orthosiphon stamineus Benth. It was found that the production of plant secondary metabolites, soluble sugars, antioxidant activity, PAL activity and LOX inhibitory activity was influenced by foliar application of ABA. As the concentration of ABA was increased from 0 to 6 µM the production of total phenolics, flavonoids, sucrose, H2O2, O2−, PAL activity and LOX inhibitory activity was enhanced. It was also observed that the antioxidant capabilities (DPPH and ORAC were increased. This was followed by increases in production of antioxidant enzymes APX, CAT and SOD. Under high application rates of ABA the net photosynthesis and stomatal conductance was found to be reduced. The production of primary and secondary metabolites displayed a significant positive relationship with H2O2 (total phenolics, r2 = 0.877; total flavonoids, r2 = 0.812; p ≤ 0.05 and O2− (total phenolics, r2 = 0.778; total flavonoids, r2 = 0.912; p ≤ 0.05. This indicated that increased oxidative stress at high application rates of ABA, improved the production of phytochemicals.

  6. Enhanced Tomato Disease Resistance Primed by Arbuscular Mycorrhizal Fungus

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    Yuanyuan eSong

    2015-09-01

    Full Text Available Roots of most terrestrial plants form symbiotic associations (mycorrhiza with soil- borne arbuscular mycorrhizal fungi (AMF. Many studies show that mycorrhizal colonization enhances plant resistance against pathogenic fungi. However, the mechanism of mycorrhiza-induced disease resistance remains equivocal. In this study, we found that mycorrhizal inoculation with AMF Funneliformis mosseae significantly alleviated tomato (Solanum lycopersicum Mill. early blight disease caused by Alternaria solani Sorauer. AMF pre-inoculation led to significant increases in activities of β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase (PAL and lipoxygenase (LOX in tomato leaves upon pathogen inoculation. Mycorrhizal inoculation alone did not influence the transcripts of most genes tested. However, pathogen attack on AMF-inoculated plants provoked strong defense responses of three genes encoding pathogenesis-related (PR proteins, PR1, PR2 and PR3, as well as defense-related genes LOX, AOC and PAL, in tomato leaves. The induction of defense responses in AMF pre-inoculated plants was much higher and more rapid than that in un-inoculated plants in present of pathogen infection. Three tomato genotypes: a Castlemart wild-type (WT plant, a jasmonate (JA biosynthesis mutant (spr2, and a prosystemin-overexpressing 35S::PS plant were used to examine the role of the JA signaling pathway in AMF-primed disease defense. Pathogen infection on mycorrhizal 35S::PS plants led to higher induction of defense-related genes and enzymes relative to WT plants. However, pathogen infection did not induce these genes and enzymes in mycorrhizal spr2 mutant plants. Bioassays showed that 35S::PS plants were more resistant and spr2 plants were more susceptible to early blight compared with WT plants. Our finding indicates that mycorrhizal colonization enhances tomato resistance to early blight by priming systemic defense response, and the JA signaling pathway is essential for

  7. Salicylic acid confers enhanced resistance to Glomerella leaf spot in apple.

    Science.gov (United States)

    Zhang, Ying; Shi, Xiangpeng; Li, Baohua; Zhang, Qingming; Liang, Wenxing; Wang, Caixia

    2016-09-01

    Glomerella leaf spot (GLS) caused by Glomerella cingulata is a newly emergent disease that results in severe defoliation and fruit spots in apple. Currently, there are no effective means to control this disease except for the traditional fungicide sprays. Induced resistance by elicitors against pathogens infection is a widely accepted eco-friendly strategy. In the present study, we investigated whether exogenous application of salicylic acid (SA) could improve resistance to GLS in a highly susceptible apple cultivar (Malus domestica Borkh. cv. 'Gala') and the underlying mechanisms. The results showed that pretreatment with SA, at 0.1-1.0 mM, induced strong resistance against GLS in 'Gala' apple leaves, with SA treated leaves showing significant reduction in lesion numbers and disease index. Concurrent with the enhanced disease resistance, SA treatment markedly increased the total antioxidant capacity (T-AOC) and defence-related enzyme activities, including catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO). As expected, SA treatment also induced the expression levels of five pathogenesis-related (PR) genes including PR1, PR5, PR8, Chitinase and β-1,3-glucanase. Furthermore, the most pronounced and/or rapid increase was observed in leaves treated with SA and subsequently inoculated with G. cingulata compared to the treatment with SA or inoculation with the pathogen. Together, these results suggest that exogenous SA triggered increase in reactive oxygen species levels and the antioxidant system might be responsible for enhanced resistance against G. cingulata in 'Gala' apple leaves. PMID:27139585

  8. Determination of the distribution and reaction of polysaccharides in wood cell walls by the isotope tracer technique, 6: Selective radio-labeling of mannan in ginkgo (Ginkgo biloba)

    International Nuclear Information System (INIS)

    D-Mannose-[2-H-3] and GDP (guanosine diphosphate)-D-mannose-[mannose-1-H-3] were administered to the shoots of ginkgo (Ginkgo biloba L.) tolabel mannan selectively in the cell walls. To suppress the incorporation of radioactivity into the lignin and cellulose, the precursors were administered in the presence of the inhibitor of phenylalanine ammonia-lyase (PAL): namely, L-alpha-aminooxy-beta-phenylpropionic acid (AOPP) and the inhibitor of glucan synthesis: namely, 2-deoxy-D-glucose (2-DG) and 2.6-dichlorobenzonitrile (2.6-DCB). When D-mannose-[2-H-3] was administered in the absence of the inhibitors, great radioactivities were found in the mannose and glucose obtained by sulfuric acid hydrolysis of the newly-formed xylem, and also in the vanillin obtained by nitrobenzene oxidation. These results indicate that the radioactivity was incorporated not only into mannan but also into cellulose and lignin. When D-mannose-[2-H-3] was administered in the presence of both AOPP and 2-DG, the radioactivities of vanillin and glucose were decreased but that of mannose was not decreased. These results indicate that the incorporations of radioactivities into lignin and cellulose were suppressed by the inhibitors, but the incorporation into mannan was not interfered with. The treatment with 2,6-DCB lessened the incorporations of radioactivity into vanillin, xylose, mannose, and glucose of the newly formed xylem considerably which indicated that 2,6-DCB disturbed the metabolic activities of the plant fatally. Consequently, the selective radiolabeling of mannan in ginkgo was achieved by the administration of D-mannose-[2-H-3], in the presence of both AOPP and 2-DG, toa growing stem. In the case of GDP-D-mannose-[mannose-1-H-3], the radioactivity incorporated into the newly-formed xylem was very little, and the selectivity in labeling and the effects of the inhibitors were not clear

  9. Combating photooxidative stress in green hairy roots of Daucus carota cultivated under light irradiation.

    Science.gov (United States)

    Mukherjee, Chiranjit; Sircar, Debabrata; Chatterjee, Moniya; Das, Sampa; Mitra, Adinpunya

    2014-01-15

    The light-dependent generation of active oxygen species, which can disrupt normal metabolic process of plant, is termed as photo-oxidative stress. Plants are equipped with enzymatic and non-enzymatic antioxidative defence system to reduce the effect of such stress. Hairy root culture of Daucus carota when cultivated under continuous illumination (250 μmol m(-2)s(-1)) turned green. To know the reason behind that and photo-oxidative stress response in green hairy roots, activities of several antioxidant enzymes were measured. When compared with normal hairy roots, green hairy roots showed an enhanced superoxide dismutase (SOD) activity. Treatment with a SOD inhibitor diethyldithiocarbamate led to suppression of SOD activity in a concentration-dependent manner in green hairy roots. Interestingly, SOD-suppressed root showed three-fold enhanced caffeic acid glucoside accumulation in the soluble fraction as compared to untreated ones. While ascorbate peroxidase activity showed marginal increase in green hairy roots, a decrease in the activities of guaiacol peroxidase and catalase were observed. SDS-PAGE of crude protein profile from green hairy roots showed a distinct band, which was absent in normal hairy roots. MALDI-TOF-MS/MS analysis of the extracted protein confirmed it as the large subunit of RuBisCO. RT-PCR based expression analysis of betaine aldehyde dehydrogenase showed enhanced transcript levels in green hairy roots as compared to normal hairy roots, whereas reverse trends were observed with the transcripts accumulation for phenylalanine ammonia-lyase and chalcone synthase. These findings corroborate with the in vitro BADH activities in hairy roots, and thus indicate an important role of this stress enzyme in combating photo-oxidative stress in green hairy roots upon continuous light exposure. PMID:24331434

  10. Using laser micro-dissection and qRT-PCR to analyze cell type-specific gene expression in Norway spruce phloem

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    Nina E. Nagy

    2014-04-01

    Full Text Available The tangentially oriented polyphenolic parenchyma (PP and radially organized ray parenchyma in the phloem are central in the defense of conifer stems against insects and pathogens. Laser micro-dissection enables examination of cell-specific defense responses. To examine induced defense responses in Norway spruce stems inoculated with the necrotrophic blue-stain fungus Ceratocystis polonica, RNA extracted from laser micro-dissected phloem parenchyma and vascular cambium was analyzed using real-time RT-PCR (qRT-PCR to profile transcript levels of selected resistance marker genes. The monitored transcripts included three pathogenesis-related proteins (class IV chitinase (CHI4, defensin (SPI1, peroxidase (PX3, two terpene synthesis related proteins (DXPS and LAS, one ethylene biosynthesis related protein (ACS, and a phenylalanine ammonia-lyase (PAL. Three days following inoculation, four genes (CHI4, PAL, PX3, SPI1 were differentially induced in individual cell and tissue types, both close to the inoculation site (5 mm above and, to a lesser degree, further away (10 mm above. These resistance marker genes were all highly induced in ray parenchyma, supporting the important role of the rays in spruce defense propagation. CHI4 and PAL were also induced in PP cells and in conducting secondary phloem tissues. Our data suggests that different cell types in the secondary phloem of Norway spruce have overlapping but not fully redundant roles in active host defense. Furthermore, the study demonstrates the usefulness of laser micro-dissection coupled with qRT-PCR to characterize gene expression in different cell types of conifer bark.

  11. Lanthanum rather than cadmium induces oxidative stress and metabolite changes in Hypericum perforatum

    International Nuclear Information System (INIS)

    Highlights: • Impact of La, Cd and Cd + La on the metabolism of Hypericum perforatum was compared. • La stimulated ROS and suppressed growth and basic antioxidants more than Cd. • Impact of Cd + La was not synergistic including the sod gene expression. • La depleted hypericin and hyp-1 gene expression but amount of hyperforin increased. • La reduced flavonols and procyanidins mainly in the roots and affected anatomy - Abstract: Physiology, oxidative stress and production of metabolites in Hypericum perforatum exposed to moderate Cd and/or La concentration (10 μM) were studied. La evoked increase in reactive oxygen species, malondialdehyde and proline but suppressed growth, tissue water content, glutathione, ascorbic acid and affected mineral nutrient contents more than Cd while the impact of Cd + La was not synergistic. Similar trend was observed at the level of superoxide dismutase gene expression. Shoot Cd amount increased in Cd + La while only root La increased in the same treatment. Extensive quantification of secondary metabolites revealed that La affected phenolic acids more pronouncedly than Cd in shoots and roots. Flavonols were suppressed by La that could contribute to the appearance of oxidative damage. Procyanidins increased in response to La in the shoots but decreased in the roots. Metabolic responses in Cd + La treatment resembled those of La treatment (almost identically in the roots). Phenylalanine ammonia-lyase activity was mainly suppressed by La. The presence of La also depleted amount of hypericin and expression of its putative gene (hyp-1) showed similar trend but accumulation of hyperforin increased under Cd or La excess. Clear differences in the stem and root anatomy in response to Cd or La were also found. Overall, H. perforatum is La-sensitive species and rather Cd ameliorated negative impact of La

  12. Exogenous silicon leads to increased antioxidant capacity in freezing-stressed pistachio leaves

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    Ghader HABIBI

    2015-11-01

    Full Text Available   Freezing stress limits photosynthesis and growth of plants. This may be attributed to the enhancement of freezing-associated oxidative damage. In this study, we followed precisely changes in the extent of lipid peroxidation and oxidative damage in leaves of pistachio (Pistacia vera ‘Ahmadaghaii’ plants exposed to foliar-applied silicon (Si under freezing stress. The foliar-applied Si decreased significantly damaging effects of cold on relative water content (RWC, accompanied by an increase in shoot fresh mass (SFM. In addition, pre-Si treatment caused a significant reduction of the leaf area lost by freezing. There was a remarkable increase in phenylalanine ammonia-lyase (PAL activity during recovery. Since leaf phenolic content was not affected by supplementary Si, the possibility that exogenously applied Si directly influences the activity of PAL seems thin. In the present work, freezing stress caused great membrane damage, as assessed by lipid peroxidation, but Si application significantly reduced the membrane damage because of an efficient scavenging by superoxide dismutase (SOD and peroxidase (POD. Under freezing, despite the increasing POD activity, Si-supplied plants accumulated the highest levels of hydrogen peroxide (H2O2 may act as a signal for recovery ability from freezing injury. A positive correlation was found between the concentration of malondialdehyde (MDA and the percentage of necrotic leaf area. This study suggests that the possible mechanisms for Si enhanced freezing resistance may be attributed to the higher antioxidant defense activity and lower lipid peroxidation through leaf water retention, in addition to its role as a mere physical barrier. 

  13. Immunization against Clostridium perfringens cells elicits protection against Clostridium tetani in mouse model: identification of cross-reactive proteins using proteomic methodologies

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    Singh Lokendra

    2008-11-01

    Full Text Available Abstract Background Clostridium tetani and Clostridium perfringens are among the medically important clostridial pathogens causing diseases in man and animals. Several homologous open reading frames (ORFs have been identified in the genomes of the two pathogens by comparative genomic analysis. We tested a likelihood of extensive sharing of common epitopes between homologous proteins of these two medically important pathogens and the possibility of cross-protection using active immunization. Results Eight predominant cross-reactive spots were identified by mass spectrometry and had hits in the C. tetani E88 proteome with significant MOWSE scores. Most of the cross-reactive proteins of C. tetani shared 65–78% sequence similarity with their closest homologues in C. perfringens ATCC13124. Electron transfer flavoprotein beta-subunit (CT3 was the most abundant protein (43.3%, followed by methylaspartate ammonia-lyase (36.8% and 2-phosphoglycerate dehydratase (35.6%. All the proteins were predicted to be cytoplasmic by PSORT protein localization algorithm. Active immunization with C. perfringens whole cells elicited cross-protective immunity against C. tetani infection in a mouse model. Conclusion Most of the dominant cross-reactive proteins of C. tetani belonged to the cluster of orthologous group (COG functional category, either of posttranslational modification, protein turnover, and chaperones (O or energy production and conversion (C. The homologs of the identified proteins have been shown to play role in pathogenesis in other Gram-positive pathogenic bacteria. Our findings provide basis for the search of potential vaccine candidates with broader coverage, encompassing more than one pathogenic clostridial species.

  14. Correlation of nitric oxide produced by an inducible nitric oxide synthase-like protein with enhanced expression of the phenylpropanoid pathway in Inonotus obliquus cocultured with Phellinus morii.

    Science.gov (United States)

    Zhao, Yanxia; Xi, Qi; Xu, Qian; He, Meihong; Ding, Jianing; Dai, Yucheng; Keller, Nancy P; Zheng, Weifa

    2015-05-01

    Fungal interspecific interactions enhance biosynthesis of phenylpropanoid metabolites (PM), and production of nitric oxide (NO) is known to be involved in this process. However, it remains unknown which signaling pathway(s) or regulator(s) mediate fungal PM biosynthesis. In this study, we cocultured two white-rot fungi, Inonotus obliquus and Phellinus morii, to examine NO production, expression of the genes involved in phenylpropanoid metabolism and accumulation of phenylpropanoid-derived polyphenols by I. obliquus. Coculture of the two fungi caused an enhanced NO biosynthesis followed by increased transcription of the genes encoding phenylalanine ammonia lyase (PAL) and 4-coumarate CoA ligase (4CL), as well as an upregulated biosynthesis of styrylpyrone polyphenols in I. obliquus. Addition of the NO synthase (NOS) selective inhibitor aminoguanidine (AG) inhibited NO production by more than 90% followed by cease in transcription of PAL and 4Cl. Treatment of guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one did not affect NO production but suppressed transcription of PAL and 4CL and reduced accumulation of total phenolic constituents. Genome-wide analysis of I. obliquus revealed two genes encoding a constitutive and an inducible NOS-like protein, respectively (cNOSL and iNOSL). Coculture of the two fungi did not increase the expression of the cNOSL gene but triggered expression of the iNOSL gene. Cloned iNOSL from Escherichia coli shows higher activity in transferring L-arginine to NO, and this activity is lost upon AG addition. Thus, iNOSL is more responsible for NO production in I. obliquus and may act as an important regulator governing PM production during fungal interspecific interactions. PMID:25582560

  15. Extraction and Separation of Active Ingredients in Schisandra chinensis (Turcz.) Baill and the Study of their Antifungal Effects

    Science.gov (United States)

    Liu, Jun; Zhang, Jie; Guo, Wei; Xiao, Weilie; Yao, Yuncong

    2016-01-01

    Schisandra chinensis extracts (SEs) have traditionally been used as an oriental medicine for the treatment of various human diseases, however, their further application in the biocontrol of plant disease remains poorly understood. This study was conducted to develop eco-friendly botanical pesticides from extracts of S. chinensis and assess whether they could play a key role in plant disease defense. Concentrated active fractions (SE-I, SE-II, and SE-III) were obtained from S. chinensis via specific extraction and separation. Then, lignan-like substances, such as Schisanhenol B, were detected via High-Performance Liquid Chromatography-ElectroSpray Ionization-Mass Spectrometry (HPLC-ESI-MS) analyses of the active fractions. Moreover, the results from biological tests on colony growth inhibition and spore germination indicated that SE-I, SE-II, and SE-III could inhibit hyphal growth and spore generation of three important plant pathogenic fungi (Monilinia fructicola, Fusarium oxysporum, and Botryosphaeria dothidea). The study of the mechanisms of resistant fungi revealed that the oxidation resistance system, including reactive oxygen species (ROS), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD), was activated. The expression of genes related to defense, such as pathogenesis-related protein (PR4), α-farnesene synthase (AFS), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) were shown to be up-regulated after treatment with SEs, which suggested an increase in apple immunity and that fruits were induced to effectively defend against the infection of pathogenic fungi (B. dothidea). This study revealed that SEs and their lignans represent promising resources for the development of safe, effective, and multi-targeted agents against pathogenic fungi. PMID:27152614

  16. Bioaccumulation and tolerance characteristics of a submerged plant (Ceratophyllum demersum L.) exposed to toxic metal lead.

    Science.gov (United States)

    Chen, Min; Zhang, Ling-Lei; Li, Jia; He, Xiao-Jia; Cai, Jun-Chi

    2015-12-01

    A hydroponic study was conducted to investigate the lead bioaccumulation and tolerance characteristics of Ceratophyllum demersum L. exposed to various lead concentrations (5-80 μM) for 7, 14 or 21 days. Lead accumulation increased with increasing concentrations of metal in the solution, to a maximum accumulation of 4016.4 mg kg(-1) dw. Unexpectedly, the release of accumulated lead from the plants into solution was observed for all experimental groups except those exposed to 5 μM. Both the biomass and protein content of the plants responded significantly to lead stress. Malondialdehyde (MDA) levels increased substantially at lead concentrations below 20 μM, further indicating that this metal is toxic to the plants. To reveal the mechanism underlying the defense against lead stress, plants were also assayed for the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), as well as other relevant enzymes such as phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO). The activities of both SOD and CAT increased at lower lead concentrations and with shorter exposure times, followed by a decline, but the activities of POD and its isoenzymes continued to increase under all conditions. Moreover, increases in the activities of PAL and PPO were observed only for the 14-day treatment, and these two enzymes were not sensitive to lead concentration. These results suggest that C. demersum exhibits strong tolerance within a specific concentration range of lead in solution; according to regression analysis, 40 μM is suggested to be this plant's tolerance threshold for lead in water. Furthermore, the malfunction of this tolerance mechanism might accelerate the metal-release process. These attributes are likely to be beneficial for utilizing C. demersum in phytoremediation applications. PMID:26300117

  17. De novo production of the flavonoid naringenin in engineered Saccharomyces cerevisiae

    Science.gov (United States)

    2012-01-01

    Background Flavonoids comprise a large family of secondary plant metabolic intermediates that exhibit a wide variety of antioxidant and human health-related properties. Plant production of flavonoids is limited by the low productivity and the complexity of the recovered flavonoids. Thus to overcome these limitations, metabolic engineering of specific pathway in microbial systems have been envisaged to produce high quantity of a single molecules. Result Saccharomyces cerevisiae was engineered to produce the key intermediate flavonoid, naringenin, solely from glucose. For this, specific naringenin biosynthesis genes from Arabidopsis thaliana were selected by comparative expression profiling and introduced in S. cerevisiae. The sole expression of these A. thaliana genes yielded low extracellular naringenin concentrations (Synthesis of aromatic amino acids was deregulated by alleviating feedback inhibition of 3-deoxy-d-arabinose-heptulosonate-7-phosphate synthase (Aro3, Aro4) and byproduct formation was reduced by eliminating phenylpyruvate decarboxylase (Aro10, Pdc5, Pdc6). Together with an increased copy number of the chalcone synthase gene and expression of a heterologous tyrosine ammonia lyase, these modifications resulted in a 40-fold increase of extracellular naringenin titers (to approximately 200 μM) in glucose-grown shake-flask cultures. In aerated, pH controlled batch reactors, extracellular naringenin concentrations of over 400 μM were reached. Conclusion The results reported in this study demonstrate that S. cerevisiae is capable of de novo production of naringenin by coexpressing the naringenin production genes from A. thaliana and optimization of the flux towards the naringenin pathway. The engineered yeast naringenin production host provides a metabolic chassis for production of a wide range of flavonoids and exploration of their biological functions. PMID:23216753

  18. Effects of UV-B on activities of enzymes of secondary phenolic metabolism in barley primary leaves

    International Nuclear Information System (INIS)

    Barley (Hordeum vulgare L.) was grown in a glasshouse with 13.56 or 8.84 kJ m−2: biologically effective UV-B (280–320 nm: UV-BBE) simulating levels predicted to occur with 25 or 5% ozone depletion at 40°N latitude, with UV-A (320–400 mm), or with no supplemental irradiation. Activities of L-phenylalanine ammonia-lyase (PAL, EC 4.3.1.5). chalcone-flavanone isomerase (CFI, EC 5.5.1.6) and peroxidase (EC 1.11.1.7) were determined from the 5th through the 30th day after planting. PAL regulates diversion of L-phenylalanine into precursors for secondary phenolics. CFI regulates an early step of flavonoid biosynthesis, and peroxidase activates phenolic precursors for cross-linking and rigidifying cell walls. At all ages UV-B decreased soluble protein leaf−1 but had little effect on fresh weight or CFI activity. Exposure to UV-B decreased peroxidase activity only slightly in early growth stages but decreased it about 40% by day 30. PAL activity was highest 5 days after planting under all treatments, decreased thereafter, and was not detectable in control plants after day 10. UV-B prolonged PAL activity through day 15 in plants given the highest level of UV-B. This UV-B prolongation of PAL activity is correlated with, and is a likely underlying mechanism to explain, the UV-B- enhanced accumulation of flavonoids and ferulic acid in barley primary leaves. The results are discussed in terms of barley leaf adaptation to UV-B as developmental response dependent on conditions of plant growth. (author)

  19. Inhibition of SlMPK1, SlMPK2, and SlMPK3 Disrupts Defense Signaling Pathways and Enhances Tomato Fruit Susceptibility to Botrytis cinerea.

    Science.gov (United States)

    Zheng, Yanyan; Yang, Yang; Liu, Can; Chen, Lin; Sheng, Jiping; Shen, Lin

    2015-06-10

    Mitogen-activated protein kinases (MAPKs) are major components of defense signaling pathways that transduce extracellular stimuli into intracellular responses in plants. Our previous study indicated that SlMPK1/2/3 were associated with nitric oxide-induced defense response in tomato fruit. In this study, we determine whether SlMPK1/2/3 influence the tomato fruit's innate immunity and whether plant hormones and reactive oxygen species (ROS) are involved in SlMPK1/2/3 defense signaling pathways. Treatment with 10 μM U0126 significantly inhibited the relative expression of SlMPK1, SlMPK2, and SlMPK3 (P fruit showed higher concentrations of auxin indole acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GA), but a lower concentration of methyl jasmonate (MeJA). The activities of defense enzymes, including β-1,3-glucanases (GLU), chitinase (CHI), phenylalanine ammonia lyase (PAL), and polyphenol oxidase (PPO), decreased after U0126 treatment. Meanwhile, H2O2 content increased, and catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) activities decreased after U0126 treatment. U0126 treatment enhanced the susceptibility of tomato fruit to Botrytis cinerea and resulted in more severe gray mold rot. These results demonstrate that inhibition of SlMPK1/2/3 disrupts tomato fruit defense signaling pathways and enhances the susceptibility to B. cinerea and also that plant hormones and ROS are associated with SlMPK1/2/3 defense signaling pathways. PMID:25910076

  20. Biocontrol efficacy and plant growth promoting activity of Bacillus altitudinis isolated from Darjeeling hills, India.

    Science.gov (United States)

    Sunar, Kiran; Dey, Pannalal; Chakraborty, Usha; Chakraborty, Bishwanath

    2015-01-01

    A total of 18 bacterial isolates were obtained from the rhizosphere of Sechium edule growing in the lower foothills of Darjeeling, India. The bacterial isolates were tested for PGPR traits in vitro such as phosphate solubilization, HCN, siderophore, IAA, chitinase, protease production as well as inhibition of pthytopathogens. Of all the bacterial isolates, one bacterium designated as BRHS/S-73 was found to possess all the tested characters which was identified on the basis of 16S rRNA gene sequence analysis as Bacillus altitudinis and was selected for in vivo studies. A significant improvement in growth measured in terms of increase in root length, shoot length, and increase in root and shoot biomass was observed when seeds of Vigna radiata, Cicer arietinum, and Glycine max were bacterized prior to sowing in field condition. Besides, the bacterium could also solubilize soil phosphate. Apart form growth promotion, root rot disease of Vigna radiata caused by Thanatephorus cucumeris was also significantly reduced by 74% when the bacterium was applied to the rhizosphere prior to pathogen challenge. The biocontrol efficacy of the bacterium was found to be 66.6% even after 30 days of pathogen inoculation. Activities of key defense related enzymes such as phenylalanine ammonia lyase, peroxidase, β-1,3-glucanase, and chitinase in both roots and leaves of treated plants were also enhanced. Results clearly suggest that B. altitudinis (BRHS/S-73) is a potential PGPR which can be used as efficient microorganism for enhancement of plant growth and suppression of fungal disease. PMID:23996212

  1. Validation of reference genes for accurate normalization of gene expression for real time-quantitative PCR in strawberry fruits using different cultivars and osmotic stresses.

    Science.gov (United States)

    Galli, Vanessa; Borowski, Joyce Moura; Perin, Ellen Cristina; Messias, Rafael da Silva; Labonde, Julia; Pereira, Ivan dos Santos; Silva, Sérgio Delmar Dos Anjos; Rombaldi, Cesar Valmor

    2015-01-10

    The increasing demand of strawberry (Fragaria×ananassa Duch) fruits is associated mainly with their sensorial characteristics and the content of antioxidant compounds. Nevertheless, the strawberry production has been hampered due to its sensitivity to abiotic stresses. Therefore, to understand the molecular mechanisms highlighting stress response is of great importance to enable genetic engineering approaches aiming to improve strawberry tolerance. However, the study of expression of genes in strawberry requires the use of suitable reference genes. In the present study, seven traditional and novel candidate reference genes were evaluated for transcript normalization in fruits of ten strawberry cultivars and two abiotic stresses, using RefFinder, which integrates the four major currently available software programs: geNorm, NormFinder, BestKeeper and the comparative delta-Ct method. The results indicate that the expression stability is dependent on the experimental conditions. The candidate reference gene DBP (DNA binding protein) was considered the most suitable to normalize expression data in samples of strawberry cultivars and under drought stress condition, and the candidate reference gene HISTH4 (histone H4) was the most stable under osmotic stresses and salt stress. The traditional genes GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and 18S (18S ribosomal RNA) were considered the most unstable genes in all conditions. The expression of phenylalanine ammonia lyase (PAL) and 9-cis epoxycarotenoid dioxygenase (NCED1) genes were used to further confirm the validated candidate reference genes, showing that the use of an inappropriate reference gene may induce erroneous results. This study is the first survey on the stability of reference genes in strawberry cultivars and osmotic stresses and provides guidelines to obtain more accurate RT-qPCR results for future breeding efforts. PMID:25445290

  2. Use Of Ultra Violet Light (UV-C) To Reduce Possible Microbial Potential In Cold Storage Rooms Loaded With Sweet Potatoes For Exportation

    International Nuclear Information System (INIS)

    Irradiation with Ultraviolet-c (UV-C) light (254 nm) was applied on sweet potatoes (cv. Abees) as well as the major recovered organisms that are accounted as contaminants in either the internal atmosphere or on sweet potato tuber roots loaded in cold storage room set at 17 degree C and 65-70% RH for 3 months. The captured types of microorganisms from either the internal atmosphere of cold storage room or surfaces of sweet potato tuber roots were fungi, yeast and bacteria with the greatest percentage of fungi that recorded 90% and 70%, respectively. The major individuals of recovered fungi were Penicillium spp., Alternaria alternata, Rhizopus stolonifer, Aspergillus spp., Botrytis cinerea, and Fusarium sp. in descending order of their existence percentages. Upon exposure, the internal atmosphere to UV-C light for one, two and three hours inside cold storage room, a significant reduction of the total number of different types of organisms was obtained with the greatest effect for the three hour-exposure time. Exposure of sweet potatoes to UV-C light at three exposure times (1, 2 and 3 hr) and stored in cold rooms for one month caused a reduction of rot percentages upon natural infection conditions with a full reduction (0 %) when irradiated for 3 hr at the same conditions. Rot percentages were decreased as the exposure time increased. Fruit characteristics in terms of tuber root firmness, shrinking and blemishing of irradiated tuber roots were remarkably maintained than which of the non irradiated ones. UV-C light caused a significant increase in phenol contents in tuber root tissue, while a reverse effect in sugar content was detected; such effects were correlated increasingly or decreasingly with the increase of exposure time. The activity of peroxidase, polyphenoloxidase or poly phenylalanine ammonia lyase (PAL) enzymes in irradiated tuber root tissues were significantly enhanced as the exposure time increased

  3. Enhanced tomato disease resistance primed by arbuscular mycorrhizal fungus.

    Science.gov (United States)

    Song, Yuanyuan; Chen, Dongmei; Lu, Kai; Sun, Zhongxiang; Zeng, Rensen

    2015-01-01

    Roots of most terrestrial plants form symbiotic associations (mycorrhiza) with soil- borne arbuscular mycorrhizal fungi (AMF). Many studies show that mycorrhizal colonization enhances plant resistance against pathogenic fungi. However, the mechanism of mycorrhiza-induced disease resistance remains equivocal. In this study, we found that mycorrhizal inoculation with AMF Funneliformis mosseae significantly alleviated tomato (Solanum lycopersicum Mill.) early blight disease caused by Alternaria solani Sorauer. AMF pre-inoculation led to significant increases in activities of β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX) in tomato leaves upon pathogen inoculation. Mycorrhizal inoculation alone did not influence the transcripts of most genes tested. However, pathogen attack on AMF-inoculated plants provoked strong defense responses of three genes encoding pathogenesis-related proteins, PR1, PR2, and PR3, as well as defense-related genes LOX, AOC, and PAL, in tomato leaves. The induction of defense responses in AMF pre-inoculated plants was much higher and more rapid than that in un-inoculated plants in present of pathogen infection. Three tomato genotypes: a Castlemart wild-type (WT) plant, a jasmonate (JA) biosynthesis mutant (spr2), and a prosystemin-overexpressing 35S::PS plant were used to examine the role of the JA signaling pathway in AMF-primed disease defense. Pathogen infection on mycorrhizal 35S::PS plants led to higher induction of defense-related genes and enzymes relative to WT plants. However, pathogen infection did not induce these genes and enzymes in mycorrhizal spr2 mutant plants. Bioassays showed that 35S::PS plants were more resistant and spr2 plants were more susceptible to early blight compared with WT plants. Our finding indicates that mycorrhizal colonization enhances tomato resistance to early blight by priming systemic defense response, and the JA signaling pathway is essential for mycorrhiza

  4. Effect of dose rate of gamma irradiation on biochemical quality and browning of mushrooms Agaricus bisporus

    Energy Technology Data Exchange (ETDEWEB)

    Beaulieu, M.; D' Aprano, G.; Lacroix, M. E-mail: monique.lacroix@inrs-iaf.uquebec.ca

    2002-03-01

    In order to enhance the shelf-life of edible mature mushrooms Agaricus bisporus, 2 kGy ionising treatments were applied at two different dose rates: 4.5 kGy/h (I{sup -}) and 32 kGy/h (I{sup +}). Both I{sup +} and I{sup -} showed 2 and 4 days shelf-life enhancement compared to the control (C). Before day 9, no significant difference (p>0.05) in L{sup *} value was detected in irradiated mushrooms. However, after day 9, the highest observed L{sup *} value (whiteness) was obtained for the mushrooms irradiated in I{sup -}. Analyses of phenolic compounds revealed that mushrooms in I{sup -} contained more phenols than I{sup +} and C, the latter containing the lower level of phenols. The polyphenol oxidase (PPO) activities of irradiated mushrooms, analysed via catechol oxidase and dopa oxidase substrates, resulted in being significantly lowered (p{<=}0.05) compared to C, with a further decrease in I{sup +}. Analyses of the enzymes indicated that PPO activity was lower in I{sup +}, contrasting with its lower phenol concentration. Ionising treatments also increased significantly (p{<=}0.05) the phenylalanine ammonia-lyase (PAL) activity. The observation of mushrooms cellular membranes, by electronic microscopy, revealed a better preserved integrity in I{sup -} than in I{sup +}. It is thus assumed that the browning effect observed in I{sup +} was caused by both the decompartimentation of vacuolar phenol and by the entry of molecular oxygen into the cell cytoplasm. The synergetic effect of the residual active PPO and the molecular oxygen, in contact with the phenols, allowed an increased oxidation rate and, therefore, a more pronounced browning in I{sup +} than in I{sup -}.

  5. Effect of dose rate of gamma irradiation on biochemical quality and browning of mushrooms Agaricus bisporus

    Science.gov (United States)

    Beaulieu, M.; D'Aprano, G.; Lacroix, M.

    2002-03-01

    In order to enhance the shelf-life of edible mature mushrooms Agaricus bisporus, 2 kGy ionising treatments were applied at two different dose rates: 4.5 kGy/h ( I-) and 32 kGy/h ( I+). Both I+ and I- showed 2 and 4 days shelf-life enhancement compared to the control ( C). Before day 9, no significant difference ( p>0.05) in L* value was detected in irradiated mushrooms. However, after day 9, the highest observed L* value (whiteness) was obtained for the mushrooms irradiated in I-. Analyses of phenolic compounds revealed that mushrooms in I- contained more phenols than I+ and C, the latter containing the lower level of phenols. The polyphenol oxidase (PPO) activities of irradiated mushrooms, analysed via catechol oxidase and dopa oxidase substrates, resulted in being significantly lowered ( p⩽0.05) compared to C, with a further decrease in I+. Analyses of the enzymes indicated that PPO activity was lower in I+, contrasting with its lower phenol concentration. Ionising treatments also increased significantly ( p⩽0.05) the phenylalanine ammonia-lyase (PAL) activity. The observation of mushrooms cellular membranes, by electronic microscopy, revealed a better preserved integrity in I- than in I+. It is thus assumed that the browning effect observed in I+ was caused by both the decompartimentation of vacuolar phenol and by the entry of molecular oxygen into the cell cytoplasm. The synergetic effect of the residual active PPO and the molecular oxygen, in contact with the phenols, allowed an increased oxidation rate and, therefore, a more pronounced browning in I+ than in I-.

  6. Substrates and enzyme activities related to biotransformation of resveratrol from phenylalanine by Alternaria sp. MG1.

    Science.gov (United States)

    Zhang, Jinhua; Shi, Junling; Liu, Yanlin

    2013-12-01

    To identify the substrates and enzymes related to resveratrol biosynthesis in Alternaria sp. MG1, different substrates were used to produce resveratrol, and their influence on resveratrol production was analyzed using high performance liquid chromatography (HPLC). Formation of resveratrol and related intermediates was identified using mass spectrum. During the biotransformation, activities of related enzymes, including phenylalanine ammonia-lyase (PAL), trans-cinnamate 4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL), were analyzed and tracked. The reaction system contained 100 mL 0.2 mol/L phosphate buffer (pH 6.5), 120 g/L Alternaria sp. MG1 cells, 0.1 g/L MgSO₄, and 0.2 g/L CaSO₄ and different substrates according to the experimental design. The biotransformation was carried out for 21 h at 28 °C and 120 rpm. Resveratrol formation was identified when phenylalanine, tyrosine, cinnamic acid, and p-coumaric acid were separately used as the only substrate. Accumulation of cinnamic acid, p-coumaric acid, and resveratrol and the activities of PAL, C4H, and 4CL were identified and changed in different trends during transformation with phenylalanine as the only substrate. The addition of carbohydrates and the increase of phenylalanine concentration promoted resveratrol production and yielded the highest value (4.57 μg/L) when 2 g/L glucose, 1 g/L cyclodextrin, and phenylalanine (4.7 mmol/L) were used simultaneously. PMID:24068334

  7. Antisense and sense expression of cDNA coding for CYP73A15, a class II cinnamate 4-hydroxylase, leads to a delayed and reduced production of lignin in tobacco

    Science.gov (United States)

    Blee, K.; Choi, J. W.; O'Connell, A. P.; Jupe, S. C.; Schuch, W.; Lewis, N. G.; Bolwell, G. P.

    2001-01-01

    A number of plant species contain the class II of genes encoding the cytochrome P450, CYP73, the cognate protein of which cinnamic acid 4-hydroxylase, is the second enzyme of the phenylpropanoid pathway. In order to begin to determine possible functionality, tobacco has been transformed with a truncated French bean class II cinnamate hydroxylase (CYP73A15) in the sense and antisense orientations. Signals for C4H protein could be detected in vascular tissue from wild-type plants using heterologous probes. The transformed plants showed a normal phenotype, even though detectable C4H protein was much reduced in tissue prints. Young propagated transformants displayed a range of reduced C4H activities, as well as either reduced or no phloroglucinol-stainable lignin. However, all mature tobacco plants showed the accumulation of lignin, even though its deposition was apparently delayed. This was not due to induction of tyrosine ammonia-lyase activity, which was not detected, but instead it is presumed due to sufficient C4H residual activity. Analysis of the lignin content of the plants showed reductions of up to 30% with a slightly reduced syringyl to guaiacyl ratio as compared to wild type. This reduction level was favourable in comparison with some other targets in the lignification pathway that have been manipulated including that of class I cinnamate 4-hydroxylase. It is proposed that the class II cinnamate 4-hydroxylase might also function in lignification in a number of species including French bean and tobacco, based on these data.

  8. Effect of Seed Treatment by Cold Plasma on the Resistance of Tomato to Ralstonia solanacearum (Bacterial Wilt)

    Science.gov (United States)

    Jiang, Jiafeng; Lu, Yufang; Li, Jiangang; Li, Ling; He, Xin; Shao, Hanliang; Dong, Yuanhua

    2014-01-01

    This study investigated the effect of cold plasma seed treatment on tomato bacterial wilt, caused by Ralstonia solanacearum (R. solanacearum), and the regulation of resistance mechanisms. The effect of cold plasma of 80W on seed germination, plant growth, nutrient uptake, disease severity, hydrogen peroxide (H2O2) concentration and activities of peroxidase (POD; EC 1.11.1.7), polyphenol oxidase (PPO; EC 1.10.3.2) and phenylalanine ammonia lyase (PAL; EC 4.3.1.5) were examined in tomato plants. Plasma treatment increased tomato resistance to R. solanacearum with an efficacy of 25.0%. Plasma treatment significantly increased both germination and plant growth in comparison with the control treatment, and plasma-treated plants absorbed more calcium and boron than the controls. In addition, H2O2 levels in treated plants rose faster and reached a higher peak, at 2.579 µM gFW−1, 140% greater than that of the control. Activities of POD (421.3 U gFW−1), PPO (508.8 U gFW−1) and PAL (707.3 U gFW−1) were also greater in the treated plants than in the controls (103.0 U gFW−1, 166.0 U gFW−1 and 309.4 U gFW−1, respectively). These results suggest that plasma treatment affects the regulation of plant growth, H2O2 concentration, and POD, PPO and PAL activity in tomato, resulting in an improved resistance to R. solanacearum. Consequently, cold plasma seed treatment has the potential to control tomato bacterial wilt caused by R. solanacearum. PMID:24840508

  9. Changes in the Antioxidant Systems as Part of the Signaling Pathway Responsible for the Programmed Cell Death Activated by Nitric Oxide and Reactive Oxygen Species in Tobacco Bright-Yellow 2 Cells1

    Science.gov (United States)

    de Pinto, Maria Concetta; Tommasi, Franca; De Gara, Laura

    2002-01-01

    Nitric oxide (NO) has been postulated to be required, together with reactive oxygen species (ROS), for the activation of the hypersensitive reaction, a defense response induced in the noncompatible plant-pathogen interaction. However, its involvement in activating programmed cell death (PCD) in plant cells has been questioned. In this paper, the involvement of the cellular antioxidant metabolism in the signal transduction triggered by these bioactive molecules has been investigated. NO and ROS levels were singularly or simultaneously increased in tobacco (Nicotiana tabacum cv Bright-Yellow 2) cells by the addition to the culture medium of NO and/or ROS generators. The individual increase in NO or ROS had different effects on the studied parameters than the simultaneous increase in the two reactive species. NO generation did not cause an increase in phenylalanine ammonia-lyase (PAL) activity or induction of cellular death. It only induced minor changes in ascorbate (ASC) and glutathione (GSH) metabolisms. An increase in ROS induced oxidative stress in the cells, causing an oxidation of the ASC and GSH redox pairs; however, it had no effect on PAL activity and did not induce cell death when it was generated at low concentrations. In contrast, the simultaneous increase of NO and ROS activated a process of death with the typical cytological and biochemical features of hypersensitive PCD and a remarkable rise in PAL activity. Under the simultaneous generation of NO and ROS, the cellular antioxidant capabilities were also suppressed. The involvement of ASC and GSH as part of the transduction pathway leading to PCD is discussed. PMID:12376637

  10. Methyl Jasmonate-Induced Lipidomic and Biochemical Alterations in the Intertidal Macroalga Gracilaria dura (Gracilariaceae, Rhodophyta).

    Science.gov (United States)

    Kumari, Puja; Reddy, C R K; Jha, Bhavanath

    2015-10-01

    The role of exogenously added methyl jasmonate (MeJA), a lipid-derived signaling compound, in inducing oxidative stress in the marine red macroalga Gracilaria dura was investigated. MeJA at a concentration of 1-100 µM was a strong stimulant of reactive oxygen species (H(2)O(2), HO· and O(2) (·-)) (P phycocyanin, with a concomitant increase in phycoerythrin. The MeJA-induced oxidative burst also led to the induction of a fatty acid oxidation cascade, resulting in the synthesis of hydroxy-oxylipins and the up-regulation of the 13-lipoxygenase pathway. Electrospray ionization-mass spectrometry-based shotgun lipidomic analysis revealed that monogalactosyldiacylglycerol (a chloroplastic glycerolipid) and phosphatidylcholine (extrachloroplastidic phopholipid) were the most affected lipid classes. The degradation of 18:3-fatty acid-containing monogalactosyldiacylglycerol inferred that it provided fatty acyl chains for the biosynthesis of 13-hydroperoxylinolenic acid, which was further directed towards either the jasmonate pathway or other alternative pathways of the fatty acid oxidation cascade, analogous to higher plants. Also, G. dura modulated the lipid acyl chains in such a way that no significant change was observed in the fatty acid profile of the treated thalli as compared with those of the control, except for C16:0, C16:1 (n-9), C20:3 (n-6) and C20:4 (n-6) (P < 0.05). Furthermore, MeJA caused the accumulation of phenolic compounds and the up-regulation of enzymes involved in secondary metabolism such as polyphenol oxidase, shikimate dehydrogenase and phenylalanine ammonia-lyase, indicating a shift towards secondary metabolism as a defense strategy to combat the induced oxidative stress. PMID:26276825

  11. Gene activation by UV light, fungal elicitor or fungal infection in Petroselinum crispum is correlated with repression of cell cycle-related genes

    International Nuclear Information System (INIS)

    The effects of UV light or fungal elicitors on plant cells have so far been studied mostly with respect to defense-related gene activation. Here, an inverse correlation of these stimulatory effects with the activities of several cell cycle-related genes is demonstrated. Concomitant with the induction of flavonoid biosynthetic enzymes in UV-irradiated cell suspension cultures of parsley (Petroselinum crispum), total histone synthesis declined to about half the initial rate. A subclass of the histone H3 gene family was selected to demonstrate the close correlation of its expression with cell division, both in intact plants and cultured cells. Using RNA-blot and run-on transcription assays, it was shown that one arbitrarily selected subclass of each of the histone H2A, H2B, H3 and H4 gene families and of the genes encoding a p34cdc2 protein kinase and a mitotic cyclin were transcriptionally repressed in UV-irradiated as well as fungal elicitor-treated parsley cells. The timing and extent of repression differed between the two stimuli; the response to light was more transient and smaller in magnitude. These differential responses to light and elicitor were inversely correlated with the induction of phenylalanine ammonia-lyase, a key enzyme of phenylpropanoid metabolism. Essentially the same result was obtained with a defined oligopeptide elicitor, indicating that the same signaling pathway is responsible for defense-related gene activation and cell cycle-related gene repression. A temporary (UV light) or long-lasting (fungal elicitor) cessation of cell culture growth is most likely due to an arrest of cell division which may be a prerequisite for full commitment of the cells to transcriptional activation of full commitment of the cells to transcriptional activation of pathways involved in UV protection or pathogen defense. This conclusion is corroborated by the observation that the histone H3 mRNA level greatly declined around fungal infection sites in young parsley

  12. Effects of Foliage Spray of KH2PO4 and Socrose Solution on Changes of Pigments and Net Photosynthetic Rate in Leaves of Red-leaf Peach in Early Summer%初夏叶面喷施KH2PO4和蔗糖对红叶桃叶片色素变化及净光合速率的影响

    Institute of Scientific and Technical Information of China (English)

    徐莉莉; 姜卫兵; 韩健; 翁忙玲; 程春燕; 化香平

    2011-01-01

    @@ 红叶桃(Prunus persica f.alropurpurea),蔷薇科(Rosaceae)李属(Prunus),落叶小乔木,是一种集观赏、食用于一体的彩叶树种,其鲜红绚丽的叶色是观赏的主要特征.但在江南地区种植的红叶桃,6月初的叶片红色消褪较快,叶色很快变绿(肖和忠等,2007),不仅缩短了观赏时期,观赏价值也大为降低,给红叶桃的生产和应用带来不利影响.%Potted seedlings of 3-year-old red-leaf peach ‘ tsukuba-6’ were used to study pigments content, soluble sugar and starch content, activity of phenylalanine ammonia-lyase (PAL), and net photosynthetic rate in leaves with the foliar spray of KH2PO4 and sucrose solution during the regreening of red-leaf in early summer. The results showed that, both KH2PO4 and sucrose solution promoted accumulation of anthocyanin (Ant) of red-leaf peach remarkably, increased the ratio of Ant, chlorophyll (Ant/Chi), the soluble sugar, starch content and activity of PAL in leaves. KH2PO4 also improved net photosynthetic rate(Pn) of red-leaf peach. Furthermore, of all the treatments, O. 3% KH2PO4 solution or 0.5% sucrose solution was best in promoting leaf-colored. The foliar spray of KH2PO4 or sucrose solution was an economic and easy method to alleviate regreening of red-leaf peach in summer for urban greening management.

  13. After-ripening induced transcriptional changes of hormonal genes in wheat seeds: the cases of brassinosteroids, ethylene, cytokinin and salicylic acid.

    Directory of Open Access Journals (Sweden)

    Vijaya R Chitnis

    Full Text Available Maintenance and release of seed dormancy is regulated by plant hormones; their levels and seed sensitivity being the critical factors. This study reports transcriptional regulation of brassinosteroids (BR, ethylene (ET, cytokinin (CK and salicylic acid (SA related wheat genes by after-ripening, a period of dry storage that decays dormancy. Changes in the expression of hormonal genes due to seed after-ripening did not occur in the anhydrobiotic state but rather in the hydrated state. After-ripening induced dormancy decay appears to be associated with imbibition mediated increase in the synthesis and signalling of BR, via transcriptional activation of de-etiolated2, dwarf4 and brassinosteroid signaling kinase, and repression of brassinosteroid insensitive 2. Our analysis is also suggestive of the significance of increased ET production, as reflected by enhanced transcription of 1-aminocyclopropane-1-carboxylic acid oxidase in after-ripened seeds, and tight regulation of seed response to ET in regulating dormancy decay. Differential transcriptions of lonely guy, zeatin O-glucosyltransferases and cytokinin oxidases, and pseudo-response regulator between dormant and after-ripened seeds implicate CK in the regulation of seed dormancy in wheat. Our analysis also reflects the association of dormancy decay in wheat with seed SA level and NPR independent SA signaling that appear to be regulated transcriptionally by phenylalanine ammonia lyase, and whirly and suppressor of npr1 inducible1 genes, respectively. Co-expression clustering of the hormonal genes implies the significance of synergistic and antagonistic interaction between the different plant hormones in regulating wheat seed dormancy. These results contribute to further our understanding of the molecular features controlling seed dormancy in wheat.

  14. Cloning and characterization of defense-related genes from Populus szechuanica infected with rust fungus Melampsora larici-populina.

    Science.gov (United States)

    Chen, Z J; Cao, Z M; Yu, Z D; Yu, D

    2016-01-01

    Characterization of defense-related genes is critical for breeding disease-resistant poplar varieties and for better management and control of leaf rust disease. In the present study, full-length cDNAs of five Populus szechuanica defense-related (PsDR) genes, pathogen-related protein 1 (PsPR1), β-1,3-glucanase (PsGns), thaumatin-like protein 1 (PsTLP1), thaumatin-like protein 2 (PsTLP2), and phenylalanine ammonia-lyase (PsPAL), were cloned from the leaves of P. szechuanica infected with Melampsora larici-populina (MLP). PsPR1 (728 bp), PsGns (1189 bp), PsTLP1 (929 bp), PsTLP2 (885 bp), and PsPAL (2586 bp) were predicted to encode 161, 347, 245, 225, and 711 amino acid residue-containing proteins with isoelectric points of 8.53, 4.96, 4.51, 7.32, and 5.87, respectively. Moreover, the deduced PsDR proteins displayed more than 90% similarity to proteins from other Populus species. In response to the avirulent isolate, Sb052, and the virulent isolate, Th053, of MLP, the expression of PsDR genes was rapidly up-regulated in the leaves of P. szechuanica, peaked at 2 or 7 days post-inoculation (dpi), with levels in the incompatible interaction being higher than those in the compatible interaction. Meanwhile, the expression of PsDR genes (except for PsGns) was also differentially up-regulated at 3, 7, or 18 dpi in the petioles of the infected leaves, leaves next to the inoculated leaves, and in the top buds of the infected plants, respectively, compared to that at 0 dpi. These results suggest that these PsDR genes could play distinctive roles in the defense response of poplar against rust infection. PMID:26909999

  15. Comparative transcriptome analysis of genes involved in anthocyanin biosynthesis in the red and yellow fruits of sweet cherry (Prunus avium L..

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    Hairong Wei

    Full Text Available Fruit color is one of the most important economic traits of the sweet cherry (Prunus avium L.. The red coloration of sweet cherry fruit is mainly attributed to anthocyanins. However, limited information is available regarding the molecular mechanisms underlying anthocyanin biosynthesis and its regulation in sweet cherry.In this study, a reference transcriptome of P. avium L. was sequenced and annotated to identify the transcriptional determinants of fruit color. Normalized cDNA libraries from red and yellow fruits were sequenced using the next-generation Illumina/Solexa sequencing platform and de novo assembly. Over 66 million high-quality reads were assembled into 43,128 unigenes using a combined assembly strategy. Then a total of 22,452 unigenes were compared to public databases using homology searches, and 20,095 of these unigenes were annotated in the Nr protein database. Furthermore, transcriptome differences between the four stages of fruit ripening were analyzed using Illumina digital gene expression (DGE profiling. Biological pathway analysis revealed that 72 unigenes were involved in anthocyanin biosynthesis. The expression patterns of unigenes encoding phenylalanine ammonia-lyase (PAL, 4-coumarate-CoA ligase (4CL, chalcone synthase (CHS, chalcone isomerase (CHI, flavanone 3-hydroxylase (F3H, flavanone 3'-hydroxylase (F3'H, dihydroflavonol 4-reductase (DFR, anthocyanidin synthase (ANS and UDP glucose: flavonol 3-O-glucosyltransferase (UFGT during fruit ripening differed between red and yellow fruit. In addition, we identified some transcription factor families (such as MYB, bHLH and WD40 that may control anthocyanin biosynthesis. We confirmed the altered expression levels of eighteen unigenes that encode anthocyanin biosynthetic enzymes and transcription factors using quantitative real-time PCR (qRT-PCR.The obtained sweet cherry transcriptome and DGE profiling data provide comprehensive gene expression information that lends insights

  16. Establishment of a yeast platform strain for production of p-coumaric acid through metabolic engineering of aromatic amino acid biosynthesis.

    Science.gov (United States)

    Rodriguez, Angelica; Kildegaard, Kanchana R; Li, Mingji; Borodina, Irina; Nielsen, Jens

    2015-09-01

    Aromatic amino acids are precursors of numerous plant secondary metabolites with diverse biological functions. Many of these secondary metabolites are already being used as active pharmaceutical or nutraceutical ingredients, and there are numerous exploratory studies of other compounds with promising applications. p-Coumaric acid is derived from aromatic amino acids and, besides being a valuable chemical building block, it serves as precursor for biosynthesis of many secondary metabolites, such as polyphenols, flavonoids, and some polyketides. Here we developed a p-coumaric acid-overproducing Saccharomyces cerevisiae platform strain. First, we reduced by-product formation by knocking out phenylpyruvate decarboxylase ARO10 and pyruvate decarboxylase PDC5. Second, different versions of feedback-resistant DAHP synthase and chorismate mutase were overexpressed. Finally, we identified shikimate kinase as another important flux-controlling step in the aromatic amino acid pathway by overexpressing enzymes from Escherichia coli, homologous to the pentafunctional enzyme Aro1p and to the bifunctional chorismate synthase-flavin reductase Aro2p. The highest titer of p-coumaric acid of 1.93 ± 0.26 g L(-1) was obtained, when overexpressing tyrosine ammonia-lyase TAL from Flavobacterium johnsoniaeu, DAHP synthase ARO4(K229L), chorismate mutase ARO7(G141S) and E. coli shikimate kinase II (aroL) in Δpdc5Δaro10 strain background. To our knowledge this is the highest reported titer of an aromatic compound produced by yeast. The developed S. cerevisiae strain represents an attractive platform host for production of p-coumaric-acid derived secondary metabolites, such as flavonoids, polyphenols, and polyketides. PMID:26292030

  17. The single functional blast resistance gene Pi54 activates a complex defence mechanism in rice.

    Science.gov (United States)

    Gupta, Santosh Kumar; Rai, Amit Kumar; Kanwar, Shamsher Singh; Chand, Duni; Singh, Nagendera Kumar; Sharma, Tilak Raj

    2012-01-01

    The Pi54 gene (Pi-k(h)) confers a high degree of resistance to diverse strains of the fungus Magnaporthe oryzae. In order to understand the genome-wide co-expression of genes in the transgenic rice plant Taipei 309 (TP) containing the Pi54 gene, microarray analysis was performed at 72 h post-inoculation of the M. oryzae strain PLP-1. A total of 1154 differentially expressing genes were identified in TP-Pi54 plants. Of these, 587 were up-regulated, whereas 567 genes were found to be down-regulated. 107 genes were found that were exclusively up-regulated and 58 genes that were down- regulated in the case of TP-Pi54. Various defence response genes, such as callose, laccase, PAL, and peroxidase, and genes related to transcription factors like NAC6, Dof zinc finger, MAD box, bZIP, and WRKY were found to be up-regulated in the transgenic line. The enzymatic activities of six plant defence response enzymes, such as peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, β-glucosidase, β-1,3-glucanase, and chitinase, were found to be significantly high in TP-Pi54 at different stages of inoculation by M. oryzae. The total phenol content also increased significantly in resistant transgenic plants after pathogen inoculation. This study suggests the activation of defence response and transcription factor-related genes and a higher expression of key enzymes involved in the defence response pathway in the rice line TP-Pi54, thus leading to incompatible host-pathogen interaction. PMID:22058403

  18. Real-Time Quantitative RT-PCR of Defense-Associated Gene Transcripts of Rhizoctonia solani-Infected Bean Seedlings in Response to Inoculation with a Nonpathogenic Binucleate Rhizoctonia Isolate.

    Science.gov (United States)

    Wen, Kui; Seguin, Philippe; St-Arnaud, Marc; Jabaji-Hare, Suha

    2005-04-01

    ABSTRACT Certain isolates of nonpathogenic binucleate Rhizoctonia spp. (np-BNR) are effective biocontrol agents against seedling root rot and damping-off. Inoculation of bean seed with np-BNR strain 232-CG at sowing reduced disease symptoms in bean (Phaseolus vulgaris) seedlings caused by R. solani. Molecular analyses of the spatial expression of three defense-associated genes were carried out using real-time quantitative reverse transcription-polymerase chain reaction (QRT-PCR) assays. This method allowed accurate quantitative evaluation of transcript levels of pG101 encoding for 1,3-beta-D-glucanase, gPAL1 encoding for phenylalanine ammonia lyase, and CHS17 encoding for chalcone synthase in 1- and 2-week-old bean seedlings that were inoculated simultaneously with np-BNR and infected with R. solani, and in seedlings that were singly inoculated with either fungi or not inoculated. In the seedlings that were infected with R. solani only, results revealed that, following infection, activation of all defense-associated gene transcripts was achieved with significant increases ranging from 7- to 40-fold greater than the control, depending on the defense gene and tissue analyzed. Seedlings that were treated with np-BNR and infected with R. solani had expression similar to those that were treated with np-BNR only, but the levels were significantly down-regulated compared with those that were infected with R. solani only. These findings indicate that disease suppression by np-BNR isolate is not correlated to pG101, gPAL1, and CHS17 gene activation. PMID:18943035

  19. Primary, secondary metabolites, photosynthetic capacity and antioxidant activity of the Malaysian Herb Kacip Fatimah (Labisia Pumila Benth) exposed to potassium fertilization under greenhouse conditions.

    Science.gov (United States)

    Ibrahim, Mohd Hafiz; Jaafar, Hawa Z E; Karimi, Ehsan; Ghasemzadeh, Ali

    2012-01-01

    A randomized complete block design was used to characterize the relationship between production of total phenolics, flavonoids, ascorbic acid, carbohydrate content, leaf gas exchange, phenylalanine ammonia-lyase (PAL), soluble protein, invertase and antioxidant enzyme activities (ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD) in Labisia pumila Benth var. alata under four levels of potassium fertilization experiments (0, 90, 180 and 270 kg K/ha) conducted for 12 weeks. It was found that the production of total phenolics, flavonoids, ascorbic acid and carbohydrate content was affected by the interaction between potassium fertilization and plant parts. As the potassium fertilization levels increased from 0 to 270 kg K/ha, the production of soluble protein and PAL activity increased steadily. At the highest potassium fertilization (270 kg K/ha) L. pumila exhibited significantly higher net photosynthesis (A), stomatal conductance (g(s)), intercellular CO(2) (C(i)), apparent quantum yield (ξ) and lower dark respiration rates (R(d)), compared to the other treatments. It was found that the production of total phenolics, flavonoids and ascorbic acid are also higher under 270 kg K/ha compared to 180, 90 and 0 kg K/ha. Furthermore, from the present study, the invertase activity was also found to be higher in 270 kg K/ha treatment. The antioxidant enzyme activities (APX, CAT and SOD) were lower under high potassium fertilization (270 kg K/ha) and have a significant negative correlation with total phenolics and flavonoid production. From this study, it was observed that the up-regulation of leaf gas exchange and downregulation of APX, CAT and SOD activities under high supplementation of potassium fertilizer enhanced the carbohydrate content that simultaneously increased the production of L. pumila secondary metabolites, thus increasing the health promoting effects of this plant. PMID:23203128

  20. Allocation of Secondary Metabolites, Photosynthetic Capacity, and Antioxidant Activity of Kacip Fatimah (Labisia pumila Benth in Response to CO2 and Light Intensity

    Directory of Open Access Journals (Sweden)

    Mohd Hafiz Ibrahim

    2014-01-01

    Full Text Available A split plot 3 by 4 experiment was designed to investigate and distinguish the relationships among production of secondary metabolites, soluble sugar, phenylalanine ammonia lyase (PAL; EC 4.3.1.5 activity, leaf gas exchange, chlorophyll content, antioxidant activity (DPPH, and lipid peroxidation under three levels of CO2 (400, 800, and 1200 μmol/mol and four levels of light intensity (225, 500, 625, and 900 μmol/m2/s over 15 weeks in Labisia pumila. The production of plant secondary metabolites, sugar, chlorophyll content, antioxidant activity, and malondialdehyde content was influenced by the interactions between CO2 and irradiance. The highest accumulation of secondary metabolites, sugar, maliondialdehyde, and DPPH activity was observed under CO2 at 1200 μmol/mol + light intensity at 225 μmol/m2/s. Meanwhile, at 400 μmol/mol CO2 + 900 μmol/m2/s light intensity the production of chlorophyll and maliondialdehyde content was the highest. As CO2 levels increased from 400 to 1200 μmol/mol the photosynthesis, stomatal conductance, fv/fm (maximum efficiency of photosystem II, and PAL activity were enhanced. The production of secondary metabolites displayed a significant negative relationship with maliondialdehyde indicating lowered oxidative stress under high CO2 and low irradiance improved the production of plant secondary metabolites that simultaneously enhanced the antioxidant activity (DPPH, thus improving the medicinal value of Labisia pumila under this condition.

  1. Primary, Secondary Metabolites, Photosynthetic Capacity and Antioxidant Activity of the Malaysian Herb Kacip Fatimah (Labisia Pumila Benth Exposed to Potassium Fertilization under Greenhouse Conditions

    Directory of Open Access Journals (Sweden)

    Ali Ghasemzadeh

    2012-11-01

    Full Text Available A randomized complete block design was used to characterize the relationship between production of total phenolics, flavonoids, ascorbic acid, carbohydrate content, leaf gas exchange, phenylalanine ammonia-lyase (PAL, soluble protein, invertase and antioxidant enzyme activities (ascorbate peroxidase (APX, catalase (CAT and superoxide dismutase (SOD in Labisia pumila Benth var. alata under four levels of potassium fertilization experiments (0, 90, 180 and 270 kg K/ha conducted for 12 weeks. It was found that the production of total phenolics, flavonoids, ascorbic acid and carbohydrate content was affected by the interaction between potassium fertilization and plant parts. As the potassium fertilization levels increased from 0 to 270 kg K/ha, the production of soluble protein and PAL activity increased steadily. At the highest potassium fertilization (270 kg K/ha L. pumila exhibited significantly higher net photosynthesis (A, stomatal conductance (gs, intercellular CO2 (Ci, apparent quantum yield (ɸ and lower dark respiration rates (Rd, compared to the other treatments. It was found that the production of total phenolics, flavonoids and ascorbic acid are also higher under 270 kg K/ha compared to 180, 90 and 0 kg K/ha. Furthermore, from the present study, the invertase activity was also found to be higher in 270 kg K/ha treatment. The antioxidant enzyme activities (APX, CAT and SOD were lower under high potassium fertilization (270 kg K/ha and have a significant negative correlation with total phenolics and flavonoid production. From this study, it was observed that the up-regulation of leaf gas exchange and downregulation of APX, CAT and SOD activities under high supplementation of potassium fertilizer enhanced the carbohydrate content that simultaneously increased the production of L. pumila secondary metabolites, thus increasing the health promoting effects of this plant.

  2. GUS gene expression driven by a citrus promoter in transgenic tobacco and 'Valencia' sweet orange Expressão do gene GUS controlado por promotor de citros em plantas transgênicas de tabaco e laranja 'Valência'

    Directory of Open Access Journals (Sweden)

    Fernando Alves de Azevedo

    2006-11-01

    Full Text Available The objective of this work was the transformation of tobacco and 'Valencia' sweet orange with the GUS gene driven by the citrus phenylalanine ammonia-lyase (PAL gene promoter (CsPP. Transformation was accomplished by co-cultivation of tobacco and 'Valência' sweet orange explants with Agrobacterium tumefaciens containing the binary vector CsPP-GUS/2201. After plant transformation and regeneration, histochemical analyses using GUS staining revealed that CsPP promoter preferentially, but not exclusively, conferred gene expression in xylem tissues of tobacco. Weaker GUS staining was also detected throughout the petiole region in tobacco and citrus CsPP transgenic plants.O objetivo deste trabalho foi realizar a transformação de plantas de tabaco e laranja 'Valência' com o gene GUS controlado pelo promotor do gene da fenilalanina amônia-liase (PAL de citros (CsPP. Foi realizada transformação genética por meio do co-cultivo de explantes de tabaco e laranja 'Valência' com Agrobacterium tumefaciens que continha o vetor binário CsPP-GUS/2201. Após a transformação e a regeneração, a detecção da atividade de GUS por ensaios histoquímicos revelou que o promotor CsPP, preferencialmente, mas não exclusivamente, confere expressão gênica em tecidos do xilema de tabaco. Expressão mais baixa de GUS também foi detectada na região de tecido de pecíolo, em plantas transgênicas (CsPP de tabaco e laranja 'Valência'.

  3. The biocontrol endophytic bacterium Pseudomonas fluorescens PICF7 induces systemic defense responses in aerial tissues upon colonization of olive roots

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    Carmen eGómez-Lama Cabanás

    2014-09-01

    Full Text Available Pseudomonas fluorescens PICF7, a native olive root endophyte and effective biocontrol agent (BCA against Verticillium wilt of olive, is able to trigger a broad range of defense responses in root tissues of this woody plant. In order to elucidate whether strain PICF7 also induces systemic defense responses in above-ground organs, aerial tissues of olive plants grown under non-gnotobiotic conditions were collected at different time points after root bacterization with this endophytic BCA. A suppression subtractive hybridization (SSH cDNA library, enriched in up-regulated genes, was generated. This strategy enabled the identification of 376 ESTs (99 contigs and 277 singlets, many of them related to response to different stresses. Five ESTs, involved in defense responses, were selected to carry out time-course quantitative real-time PCR (qRT-PCR experiments aiming to: (i validate the induction of these genes, and (ii shed light on their expression pattern along time (from 1 to 15 days. Induction of olive genes potentially coding for lypoxigenase 2, catalase, 1-aminocyclopropane-1-carboxylate oxidase and phenylananine ammonia-lyase was thus confirmed at some time points. Computational analysis also revealed that different transcription factors were up-regulated in olive aerial tissues (i.e. jerf, bHLH, WRKYs, as previously reported for roots. Results confirmed that root colonization by this endophytic bacterium does not only trigger defense responses in this organ but also mount a wide array of systemic defense responses in distant tissues (stems, leaves. This sheds light on how olive plants respond to the ‘non-hostile’ colonization by a bacterial endophyte and how induced defense response can contribute to the biocontrol activity of strain PICF7.

  4. [Synergistion mechanism of exogenous Ca2+ to SA-induced resistance to Botrytis cinerea in tomato].

    Science.gov (United States)

    Li, Lin-lin; Li, Tian-lai; Jiang, Guo-bin; Jin, Hua; Zou, Ji-xiang

    2015-11-01

    In this study, we investigated the effect of exogenous calcium and salicylic acid (SA) on Botrytis cinerea resistance in tomato seedlings. We treated a tomato strain susceptible to Botrytis cinerea with foliar spraying of water, SA, SA+CaCl2 and SA+EGTA (Ca2+ chelating agent) for one to five days. During the treatment, leaves were collected to analyze the reactive oxygen species (ROS) content, phenylalanine ammonia lyase (PAL) activity, chintase and β-1,3-glucanase levels, and the expression of pathogenesis related protein 1, 2, 3 (PR1, PR2, PR3). Three days after infection, the disease index was 74.8 in control plants, and 46.9, 38.5 and 70.3 in SA, SA+Ca and SA+ EGTA treated plants, respectively. SA treatment significantly increased ROS leaf accumulation, and activities of PAL, chintase and β-1,3-glucanase. These values were further enhanced in SA+Ca treated plants, but decreased in SA+EGTA treated plants. Application of SA significantly increased the expression levels of PR1, PR2a and PR3b, which were further elevated by the combination treatment with Ca2+. These effects were counteracted by the combination treatment of SA and EGTA. The transcription levels of PR2b and PR3a were up-regulated by 1-2 folds, and PR1, 2a and 3b by 2-5 folds in SA- and SA+Ca-treated plants relative to control. These data suggested that application of Ca2+ could synergistically increase SA-induced resistance to B. cinerea. The resistance was associated with ROS accumulation, therefore the increase in resistance might be through ROS ability to increase the activity of defense-related enzymes and expression levels of PR1, PR2a and PR3b. PMID:26915208

  5. Effect of ultraviolet-C light on postharvest decay of strawberry

    International Nuclear Information System (INIS)

    The effect of ultraviolet-C light (u.v.-C) at low doses on postharvest decay of strawberries caused by Botrytis cinerea and other pathogens was investigated. Phenylalanine ammonia-lyase (PAL) activity and ethylene production, as influenced by ultraviolet-C irradiation, were also determined. Strawberries (cv. ‘Pajaro’) from plants that had been treated with chemicals against grey mould were irradiated with u.v.-C doses ranging from 0.25 to 4.00 kJ m-2 and inoculated with B. cinerea at different times (0, 12, 24 and 48 hours) after irradiation. To assess the effect of u.v.-C light on the naturally occurring postharvest decay, organically grown strawberries were also used. After treatment the strawberries were stored at 20±1°C or at 3°C. u.v.-C doses at 0.50 and 1.00 kJ m-2 significantly reduced botrytis storage rot arising from both artificial inoculations and natural infections in comparison with the unirradiated control. The doses shown to reduce botrytis rot produced an increase in PAL activity 12 h after irradiation; this result indicates the activation of metabolic a pathway related to the biosynthesis of phenolic compounds, which are usually characterized by antifungal activity. In addition, u.v.-C irradiation caused an increase in ethylene production proportional to the doses applied, reaching the highest value 6 h after treatment. The overall results from these investigations indicate that treatment with low u.v.-C doses produces a reduction in postharvest decay of strawberries related to induced resistance mechanisms. Moreover, a germicidal effect of reducing external contaminating pathogens cannot be excluded

  6. Growth and physiological changes in continuously cropped eggplant (Solanum melongena L. upon relay intercropping with garlic (Allium sativum L.

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    Mengyi eWang

    2015-04-01

    Full Text Available Relay intercropping represents an alternative for sustainable production of vegetables, but the changes of internally antioxidant defense combined with the growth and yield are not clear. Field experiment was carried out to investigate the malondialdehyde (MDA content and activity levels of superoxide dismutase (SOD, peroxidase (POD, polyphenol oxidase (PPO and phenylalanine ammonia-lyase (PAL in eggplant (Solanum melongena L. and plant height, stem diameter, maximal leaf area and yield of eggplant grown under successive cropping in the year 2011 and 2012 to see if relay intercropping with garlic (Allium sativum L. could benefit to eggplant growth and yield. Three experimental treatments with three repeats in each were carried out (completely randomized block design: eggplant monoculture (CK, eggplant/normal garlic relay intercropping (NG, and eggplant/green garlic relay intercropping (GG. In both years, the MDA content was significantly lower and SOD and POD activities were generally lower in NG and GG compared with CK in most sampling dates. PPO activity trends were generally opposite to those of POD. The general trend of PAL activity was similar to MDA. The plant height and stem of eggplant was lower, but the maximal leaf area was larger in NG and GG in 2011; in 2012 the plant growth was stronger in relay intercropping treatments. For eggplant yield in 2011, NG was 2.85% higher than CK; after the time for the green garlic pulled out was moved forward in 2012, the yield was increased by 6.26% and 7.80% respectively in NG and GG. The lower MDA content and enzyme activities in relay intercropping treatments showed that the eggplant suffered less damage from environment and continuous cropping obstacles, which promoted healthier plant. Thus from both the growth and physiological perspective, it was concluded that eggplant/garlic relay intercropping is a beneficial cultivation practice maintaining stronger plant growth and higher yield.

  7. Arbuscular mycorrhizal fungi (AMF) as bio protector agents against wilt induced by Verticillium spp. in pepper

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, N.; Garmendia, I.; Sanchez-Diaz, M.; Aguirreolea, J.

    2010-07-01

    Verticillium dahliae Kleb. is a vascular pathogen that alters water status and growth of pepper plants and causes drastic reductions in yield. Its control is difficult because it can survive in field soil for several years. The application of arbuscular mycorrhizal fungi (AMF) as bio protector agents against V. dahliae is an alternative to the use of chemicals which, in addition, is more respectful with the environment. The establishment of the mutualistic association of plant roots and AMF involves a continuous cellular and molecular dialogue between both symbionts that includes the pre activation of plant defense responses that may enhance the resistance or tolerance of mycorrhizal plants to soil-borne pathogens. Some AMF can improve the resistance of Capsicum annuum L. against V. dahliae. This is especially relevant for pepper cultivars (i.e. cv. Piquillo) that exhibit high susceptibility to this pathogen. Compared with non-mycorrhizal plants, mycorrhizal pepper can exhibit more balanced antioxidant metabolism in leaves along the first month after pathogen inoculation, which may contribute to delay both the development of disease symptoms and the decrease of photosynthesis in Verticillium-inoculated plants with the subsequent benefit for yield. In stems, mycorrhizal pepper show earlier and higher deposition of lignin in xylem vessels than non mycorrhizal plants, even in absence of the pathogen. Moreover, AMF can induce new isoforms of acidic chitinases and superoxide dismutase in roots. Mycorrhizal-specific induction of these enzymatic activities together with enhanced peroxidase and phenylalanine ammonia-lyase in roots may also be involved in the bio protection of Verticillium-induced wilt in pepper by AMF. (Author) 81 refs.

  8. Aminooxy-naphthylpropionic acid and its derivatives are inhibitors of auxin biosynthesis targeting l-tryptophan aminotransferase: structure-activity relationships.

    Science.gov (United States)

    Narukawa-Nara, Megumi; Nakamura, Ayako; Kikuzato, Ko; Kakei, Yusuke; Sato, Akiko; Mitani, Yuka; Yamasaki-Kokudo, Yumiko; Ishii, Takahiro; Hayashi, Ken-Ichiro; Asami, Tadao; Ogura, Takehiko; Yoshida, Shigeo; Fujioka, Shozo; Kamakura, Takashi; Kawatsu, Tsutomu; Tachikawa, Masanori; Soeno, Kazuo; Shimada, Yukihisa

    2016-08-01

    We previously reported l-α-aminooxy-phenylpropionic acid (AOPP) to be an inhibitor of auxin biosynthesis, but its precise molecular target was not identified. In this study we found that AOPP targets TRYPTOPHAN AMINOTRANSFERASE of ARABIDOPSIS 1 (TAA1). We then synthesized 14 novel compounds derived from AOPP to study the structure-activity relationships of TAA1 inhibitors in vitro. The aminooxy and carboxy groups of the compounds were essential for inhibition of TAA1 in vitro. Docking simulation analysis revealed that the inhibitory activity of the compounds was correlated with their binding energy with TAA1. These active compounds reduced the endogenous indole-3-acetic acid (IAA) content upon application to Arabidopsis seedlings. Among the compounds, we selected 2-(aminooxy)-3-(naphthalen-2-yl)propanoic acid (KOK1169/AONP) and analyzed its activities in vitro and in vivo. Arabidopsis seedlings treated with KOK1169 showed typical auxin-deficient phenotypes, which were reversed by exogenous IAA. In vitro and in vivo experiments indicated that KOK1169 is more specific for TAA1 than other enzymes, such as phenylalanine ammonia-lyase. We further tested 41 novel compounds with aminooxy and carboxy groups to which we added protection groups to increase their calculated hydrophobicity. Most of these compounds decreased the endogenous auxin level to a greater degree than the original compounds, and resulted in a maximum reduction of about 90% in the endogenous IAA level in Arabidopsis seedlings. We conclude that the newly developed compounds constitute a class of inhibitors of TAA1. We designated them 'pyruvamine'. PMID:27147230

  9. Heteroconium chaetospira induces resistance to clubroot via upregulation of host genes involved in jasmonic acid, ethylene, and auxin biosynthesis.

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    Rachid Lahlali

    Full Text Available An endophytic fungus, Heteroconium chaetospira isolate BC2HB1 (Hc, suppressed clubroot (Plasmodiophora brassicae -Pb on canola in growth-cabinet trials. Confocal microscopy demonstrated that Hc penetrated canola roots and colonized cortical tissues. Based on qPCR analysis, the amount of Hc DNA found in canola roots at 14 days after treatment was negatively correlated (r = 0.92, P<0.001 with the severity of clubroot at 5 weeks after treatment at a low (2×10(5 spores pot(-1 but not high (2×10(5 spores pot(-1 dose of pathogen inoculum. Transcript levels of nine B. napus (Bn genes in roots treated with Hc plus Pb, Pb alone and a nontreated control were analyzed using qPCR supplemented with biochemical analysis for the activity of phenylalanine ammonia lyases (PAL. These genes encode enzymes involved in several biosynthetic pathways related potentially to plant defence. Hc plus Pb increased the activity of PAL but not that of the other two genes (BnCCR and BnOPCL involved also in phenylpropanoid biosynthesis, relative to Pb inoculation alone. In contrast, expression of several genes involved in the jasmonic acid (BnOPR2, ethylene (BnACO, auxin (BnAAO1, and PR-2 protein (BnPR-2 biosynthesis were upregulated by 63, 48, 3, and 3 fold, respectively, by Hc plus Pb over Pb alone. This indicates that these genes may be involved in inducing resistance in canola by Hc against clubroot. The upregulation of BnAAO1 appears to be related to both pathogenesis of clubroot and induced defence mechanisms in canola roots. This is the first report on regulation of specific host genes involved in induced plant resistance by a non-mycorrhizal endophyte.

  10. Lanthanum rather than cadmium induces oxidative stress and metabolite changes in Hypericum perforatum

    Energy Technology Data Exchange (ETDEWEB)

    Babula, Petr [Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 753/5, 625 00 Brno (Czech Republic); Klejdus, Bořivoj [Institute of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic); CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic); Kovacik, Jozef, E-mail: jozkovacik@yahoo.com [Institute of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic); CEITEC–Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic); Hedbavny, Josef; Hlavna, Marián [Institute of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic)

    2015-04-09

    Highlights: • Impact of La, Cd and Cd + La on the metabolism of Hypericum perforatum was compared. • La stimulated ROS and suppressed growth and basic antioxidants more than Cd. • Impact of Cd + La was not synergistic including the sod gene expression. • La depleted hypericin and hyp-1 gene expression but amount of hyperforin increased. • La reduced flavonols and procyanidins mainly in the roots and affected anatomy - Abstract: Physiology, oxidative stress and production of metabolites in Hypericum perforatum exposed to moderate Cd and/or La concentration (10 μM) were studied. La evoked increase in reactive oxygen species, malondialdehyde and proline but suppressed growth, tissue water content, glutathione, ascorbic acid and affected mineral nutrient contents more than Cd while the impact of Cd + La was not synergistic. Similar trend was observed at the level of superoxide dismutase gene expression. Shoot Cd amount increased in Cd + La while only root La increased in the same treatment. Extensive quantification of secondary metabolites revealed that La affected phenolic acids more pronouncedly than Cd in shoots and roots. Flavonols were suppressed by La that could contribute to the appearance of oxidative damage. Procyanidins increased in response to La in the shoots but decreased in the roots. Metabolic responses in Cd + La treatment resembled those of La treatment (almost identically in the roots). Phenylalanine ammonia-lyase activity was mainly suppressed by La. The presence of La also depleted amount of hypericin and expression of its putative gene (hyp-1) showed similar trend but accumulation of hyperforin increased under Cd or La excess. Clear differences in the stem and root anatomy in response to Cd or La were also found. Overall, H. perforatum is La-sensitive species and rather Cd ameliorated negative impact of La.

  11. Effects of ambient and elevated CO2 on growth, chlorophyll fluorescence, photosynthetic pigments, antioxidants, and secondary metabolites of Catharanthus roseus (L.) G Don. grown under three different soil N levels.

    Science.gov (United States)

    Singh, Aradhana; Agrawal, Madhoolika

    2015-03-01

    Catharanthus roseus L. plants were grown under ambient (375 ± 30 ppm) and elevated (560 ± 25 ppm) concentrations of atmospheric CO2 at different rates of N supply (without supplemental N, 0 kg N ha(-1); recommended N, 50 kg N ha(-1); and double recommended N, 100 kg N ha(-1)) in open top chambers under field condition. Elevated CO2 significantly increased photosynthetic pigments, photosynthetic efficiency, and organic carbon content in leaves at recommended (RN) and double recommended N (DRN), while significantly decreased total nitrogen content in without supplemental N (WSN). Activities of superoxide dismutase, catalase, and ascorbate peroxidase were declined, while glutathione reductase, peroxidase, and phenylalanine-ammonia lyase were stimulated under elevated CO2. However, the responses of the above enzymes were modified with different rates of N supply. Elevated CO2 significantly reduced superoxide production rate, hydrogen peroxide, and malondialdehyde contents in RN and DRN. Compared with ambient, total alkaloids content increased maximally at recommended level of N, while total phenolics in WSN under elevated CO2. Elevated CO2 stimulated growth of plants by increasing plant height and numbers of branches and leaves, and the magnitude of increment were maximum in DRN. The study suggests that elevated CO2 has positively affected plants by increasing growth and alkaloids production and reducing the level of oxidative stress. However, the positive effects of elevated CO2 were comparatively lesser in plants grown under limited N availability than in moderate and higher N availability. Furthermore, the excess N supply in DRN has stimulated the growth but not the alkaloids production under elevated CO2. PMID:25304238

  12. Enhanced tomato disease resistance primed by arbuscular mycorrhizal fungus

    Science.gov (United States)

    Song, Yuanyuan; Chen, Dongmei; Lu, Kai; Sun, Zhongxiang; Zeng, Rensen

    2015-01-01

    Roots of most terrestrial plants form symbiotic associations (mycorrhiza) with soil- borne arbuscular mycorrhizal fungi (AMF). Many studies show that mycorrhizal colonization enhances plant resistance against pathogenic fungi. However, the mechanism of mycorrhiza-induced disease resistance remains equivocal. In this study, we found that mycorrhizal inoculation with AMF Funneliformis mosseae significantly alleviated tomato (Solanum lycopersicum Mill.) early blight disease caused by Alternaria solani Sorauer. AMF pre-inoculation led to significant increases in activities of β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX) in tomato leaves upon pathogen inoculation. Mycorrhizal inoculation alone did not influence the transcripts of most genes tested. However, pathogen attack on AMF-inoculated plants provoked strong defense responses of three genes encoding pathogenesis-related proteins, PR1, PR2, and PR3, as well as defense-related genes LOX, AOC, and PAL, in tomato leaves. The induction of defense responses in AMF pre-inoculated plants was much higher and more rapid than that in un-inoculated plants in present of pathogen infection. Three tomato genotypes: a Castlemart wild-type (WT) plant, a jasmonate (JA) biosynthesis mutant (spr2), and a prosystemin-overexpressing 35S::PS plant were used to examine the role of the JA signaling pathway in AMF-primed disease defense. Pathogen infection on mycorrhizal 35S::PS plants led to higher induction of defense-related genes and enzymes relative to WT plants. However, pathogen infection did not induce these genes and enzymes in mycorrhizal spr2 mutant plants. Bioassays showed that 35S::PS plants were more resistant and spr2 plants were more susceptible to early blight compared with WT plants. Our finding indicates that mycorrhizal colonization enhances tomato resistance to early blight by priming systemic defense response, and the JA signaling pathway is essential for mycorrhiza

  13. Identification and analysis of miRNAs and their targets in ginger using bioinformatics approach.

    Science.gov (United States)

    Singh, Noopur; Srivastava, Swati; Sharma, Ashok

    2016-01-10

    MicroRNAs (miRNAs) are a large family of endogenous small RNAs derived from the non-protein coding genes. miRNA regulates the gene expression at the post-transcriptional level and plays an important role in plant development. Zingiber officinale is an important medicinal plant having numerous therapeutic properties. Its bioactive compound gingerol and essential oil posses important pharmacological and physiological activities. In this study, we used a homology search based computational approach for identifying miRNAs in Z. officinale. A total of 16 potential miRNA families (miR167, miR407, miR414, miR5015, miR5021, miR5644, miR5645, miR5656, miR5658, miR5664, miR827, miR838, miR847, miR854, miR862 and miR864) were predicted in ginger. Phylogenetic and conserved analyses were performed for predicted miRNAs. Thirteen miRNA families were found to regulate 300 target transcripts and play an important role in cell signaling, reproduction, metabolic process and stress. To understand the miRNA mediated gene regulatory control and to validate miRNA target predictions, a biological network was also constructed. Gene ontology and pathway analyses were also done. miR5015 was observed to regulate the biosynthesis of gingerol by inhibiting phenyl ammonia lyase (PAL), a precursor enzyme in the biosynthesis of gingerol. Our results revealed that most of the predicted miRNAs were involved in the regulation of rhizome development. miR5021, miR854 and miR838 were identified to regulate the rhizome development and the essential oil biosynthesis in ginger. PMID:26392033

  14. Biphenyl 4-Hydroxylases Involved in Aucuparin Biosynthesis in Rowan and Apple Are Cytochrome P450 736A Proteins.

    Science.gov (United States)

    Sircar, Debabrata; Gaid, Mariam M; Chizzali, Cornelia; Reckwell, Dennis; Kaufholdt, David; Beuerle, Till; Broggini, Giovanni A L; Flachowsky, Henryk; Liu, Benye; Hänsch, Robert; Beerhues, Ludger

    2015-06-01

    Upon pathogen attack, fruit trees such as apple (Malus spp.) and pear (Pyrus spp.) accumulate biphenyl and dibenzofuran phytoalexins, with aucuparin as a major biphenyl compound. 4-Hydroxylation of the biphenyl scaffold, formed by biphenyl synthase (BIS), is catalyzed by a cytochrome P450 (CYP). The biphenyl 4-hydroxylase (B4H) coding sequence of rowan (Sorbus aucuparia) was isolated and functionally expressed in yeast (Saccharomyces cerevisiae). SaB4H was named CYP736A107. No catalytic function of CYP736 was known previously. SaB4H exhibited absolute specificity for 3-hydroxy-5-methoxybiphenyl. In rowan cell cultures treated with elicitor from the scab fungus, transient increases in the SaB4H, SaBIS, and phenylalanine ammonia lyase transcript levels preceded phytoalexin accumulation. Transient expression of a carboxyl-terminal reporter gene construct directed SaB4H to the endoplasmic reticulum. A construct lacking the amino-terminal leader and transmembrane domain caused cytoplasmic localization. Functional B4H coding sequences were also isolated from two apple (Malus × domestica) cultivars. The MdB4Hs were named CYP736A163. When stems of cv Golden Delicious were infected with the fire blight bacterium, highest MdB4H transcript levels were observed in the transition zone. In a phylogenetic tree, the three B4Hs were closest to coniferaldehyde 5-hydroxylases involved in lignin biosynthesis, suggesting a common ancestor. Coniferaldehyde and related compounds were not converted by SaB4H. PMID:25862456

  15. Sugarcane expressed sequences tags (ESTs encoding enzymes involved in lignin biosynthesis pathways

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    Ramos Rose Lucia Braz

    2001-01-01

    Full Text Available Lignins are phenolic polymers found in the secondary wall of plant conductive systems where they play an important role by reducing the permeability of the cell wall to water. Lignins are also responsible for the rigidity of the cell wall and are involved in mechanisms of resistance to pathogens. The metabolic routes and enzymes involved in synthesis of lignins have been largely characterized and representative genes that encode enzymes involved in these processes have been cloned from several plant species. The synthesis of lignins is liked to the general metabolism of the phenylpropanoids in plants, having enzymes (e.g. phenylalanine ammonia-lyase (PAL, cinnamate 4-hydroxylase (C4H and caffeic acid O-methyltransferase (COMT common to other processes as well as specific enzymes such as cinnamoyl-CoA reductase (CCR and cinnamyl alcohol dehydrogenase (CAD. Some maize and sorghum mutants, shown to have defective in CAD and/or COMT activity, are easier to digest because they have a reduced lignin content, something which has motivated different research groups to alter the lignin content and composition of model plants by genetic engineering try to improve, for example, the efficiency of paper pulping and digestibility. In the work reported in this paper, we have made an inventory of the sugarcane expressed sequence tag (EST coding for enzymes involved in lignin metabolism which are present in the sugarcane EST genome project (SUCEST database. Our analysis focused on the key enzymes ferulate-5-hydroxylase (F5H, caffeic acid O-methyltransferase (COMT, caffeoyl CoA O-methyltransferase (CCoAOMT, hydroxycinnamate CoA ligase (4CL, cinnamoyl-CoA reductase (CCR and cinnamyl alcohol dehydrogenase (CAD. The comparative analysis of these genes with those described in other species could be used as molecular markers for breeding as well as for the manipulation of lignin metabolism in sugarcane.

  16. Hypersensitive response of Sesamum prostratum Retz. elicitated by Fusarium oxysporum f. sesame (Schelt) Jacz Butler.

    Science.gov (United States)

    Rajab, Reeja; Rajan, S Sajitha; Satheesh, L Shilpa; Harish, S R; Sunukumar, S S; Sandeep, B S; Mohan, T C Kishor; Murugan, K

    2009-10-01

    Aim of this study was to investigate the intensity and timing of the ROS formation, lipid peroxidation and expression of antioxidant enzymes as initial responses of calli of Sesamum prostratum (SP) against Fusarium oxysporum f. sesame crude toxin metabolite of varying concentrations. 2,4 dichlorophenoxy acetic acid (2,4-D) / coconut milk combinations were found to be more efficient among different hormonal regimes (2,4 -D, 2,4-D/casein hydrosylate and 2,4-D/ coconut milk). The concentration of hydrogen peroxide and lipid peroxidation were higher (13.2 and 5.7-folds, respectively) after 6 h in the treated callus confirmed the oxidative stress. An increase in total phenolics was also detected in inoculated callus. Increased activity of antioxidative enzymes viz., NADPH oxidase and superoxide dismutase (SOD) corroborate with the high level of ROSs, such as O2*- and H2O2. The poor activity of catalase confirmed the oxidative burst in the callus leading to necrosis. Activity of peroxidase was at par with total phenolics. Similarly, phenylalanine ammonia lyase (PAL) also showed high activity revealing the active phase in the synthesis of secondary metabolites in the plant. The oxidative burst generated in the interaction between Sesamum and F. oxysporum f. sesame toxin might be the first line of defense by the host mounted against the invading necrotrophic pathogen. The results suggested that the rapid production of reactive oxygen species in the callus in response to fungal toxin had been proposed to orchestrate the establishment of different defensive barriers against the pathogens. PMID:20112812

  17. Are ineffective defence reactions potential target for induced resistance during the compatible wheat-powdery mildew interaction?

    Science.gov (United States)

    Tayeh, Ch; Randoux, B; Tisserant, B; Khong, G; Jacques, Ph; Reignault, Ph

    2015-11-01

    Powdery mildew caused by Blumeria graminis f.sp. tritici, an obligate aerial biotrophic fungus, would be one of the most damaging wheat (Triticum aestivum) diseases without the extensive use of conventional fungicides. In our study, the expression levels of some basal defence-related genes were investigated during a compatible interaction in order to evaluate wheat reactions to infection, along with the different stages of the infectious process in planta. As fungal conidia initiated their germination and developed appressorial germ tube (AGT), early defence reactions involved the expression of a lipoxygenase (LOX)- and an oxalate oxidase (OXO)-encoding genes, followed by activations of corresponding LOX (EC 1.13.11.12) and OXO (EC 1.2.3.4) activities, respectively. When penetration of AGT took place, up-regulation of chitinases (CHI) and PR1-encoding genes expression occurred along with an increase of CHI (EC 3.2.1.14) activity. Meanwhile, expression of a phenylalanine ammonia-lyase-encoding gene also took place. Up-regulation of a phospholipase C- and lipid transfer proteins-encoding genes expression occurred during the latest stages of infection. Neither the phi glutathione S-transferase (GST)-encoding gene expression nor the GST (EC 2.5.1.13) activity was modified upon wheat infection by powdery mildew. Whether these defence reactions during such a compatible interaction are markers of immunity or susceptibility, and whether they have the ability to contribute to protection upon modulation of their timing and their intensity by resistance inducers are discussed. PMID:26218548

  18. Characterization of a Lignified Secondary Phloem Fibre‐deficient Mutant of Jute (Corchorus capsularis)

    Science.gov (United States)

    SENGUPTA, GARGI; PALIT, P.

    2004-01-01

    • Background and Aims High lignin content of lignocellulose jute fibre does not favour its utilization in making finer fabrics and other value‐added products. To aid the development of low‐lignin jute fibre, this study aimed to identify a phloem fibre mutant with reduced lignin. • Methods An x‐ray‐induced mutant line (CMU) of jute (Corchorus capsularis) was morphologically evaluated and the accession (CMU 013) with the most undulated phenotype was compared with its normal parent (JRC 212) for its growth, secondary fibre development and lignification of the fibre cell wall. • Key Results The normal and mutant plants showed similar leaf photosynthetic rates. The mutant grew more slowly, had shorter internodes and yielded much less fibre after retting. The fibre of the mutant contained 50 % less lignin but comparatively more cellulose than that of the normal type. Differentiation of primary and secondary vascular tissues throughout the CMU 013 stem was regular but it did not have secondary phloem fibre bundles as in JRC 212. Instead, a few thin‐walled, less lignified fibre cells formed uni‐ or biseriate radial rows within the phloem wedges of the middle stem. The lower and earliest developed part of the mutant stem had no lignified fibre cells. This developmental deficiency in lignification of fibre cells was correlated to a similar deficiency in phenylalanine ammonia lyase activity, but not peroxidase activity, in the bark tissue along the stem axis. In spite of severe reduction in lignin synthesis in the phloem cells this mutant functioned normally and bred true. • Conclusions In view of the observations made, the mutant is designated as deficient lignified phloem fibre (dlpf). This mutant may be utilized to engineer low‐lignin jute fibre strains and may also serve as a model to study the positional information that coordinates secondary wall thickening of fibre cells. PMID:14707004

  19. In silico differential display of defense-related expressed sequence tags from sugarcane tissues infected with diazotrophic endophytes

    Directory of Open Access Journals (Sweden)

    Lambais Marcio R.

    2001-01-01

    Full Text Available The expression patterns of 277 sugarcane expressed sequence tags (EST-contigs encoding putative defense-related (DR proteins were evaluated using the Sugarcane EST database. The DR proteins evaluated included chitinases, beta-1,3-glucanases, phenylalanine ammonia-lyases, chalcone synthases, chalcone isomerases, isoflavone reductases, hydroxyproline-rich glycoproteins, proline-rich glycoproteins, peroxidases, catalases, superoxide dismutases, WRKY-like transcription factors and proteins involved in cell death control. Putative sugarcane WRKY proteins were compared and their phylogenetic relationships determined. A hierarchical clustering approach was used to identify DR ESTs with similar expression profiles in representative cDNA libraries. To identify DR ESTs differentially expressed in sugarcane tissues infected with Gluconacetobacter diazotrophicus or Herbaspirillum rubrisubalbicans, 179 putative DR EST-contigs expressed in non-infected tissues (leaves and roots and/or infected tissues were selected and arrayed by similarity of their expression profiles. Changes in the expression levels of 124 putative DR EST-contigs, expressed in non-infected tissues, were evaluated in infected tissues. Approximately 42% of these EST-contigs showed no expression in infected tissues, whereas 15% and 3% showed more than 2-fold suppression in tissues infected with G. diazotrophicus or H. rubrisubalbicans, respectively. Approximately 14 and 8% of the DR EST-contigs evaluated showed more than 2-fold induction in tissues infected with G. diazotrophicus or H. rubrisubalbicans, respectively. The differential expression of clusters of DR genes may be important in the establishment of a compatible interaction between sugarcane and diazotrophic endophytes. It is suggested that the hierarchical clustering approach can be used on a genome-wide scale to identify genes likely involved in controlling plant-microorganism interactions.

  20. Effect of dose rate of gamma irradiation on biochemical quality and browning of mushrooms Agaricus bisporus

    International Nuclear Information System (INIS)

    In order to enhance the shelf-life of edible mature mushrooms Agaricus bisporus, 2 kGy ionising treatments were applied at two different dose rates: 4.5 kGy/h (I-) and 32 kGy/h (I+). Both I+ and I- showed 2 and 4 days shelf-life enhancement compared to the control (C). Before day 9, no significant difference (p>0.05) in L* value was detected in irradiated mushrooms. However, after day 9, the highest observed L* value (whiteness) was obtained for the mushrooms irradiated in I-. Analyses of phenolic compounds revealed that mushrooms in I- contained more phenols than I+ and C, the latter containing the lower level of phenols. The polyphenol oxidase (PPO) activities of irradiated mushrooms, analysed via catechol oxidase and dopa oxidase substrates, resulted in being significantly lowered (p≤0.05) compared to C, with a further decrease in I+. Analyses of the enzymes indicated that PPO activity was lower in I+, contrasting with its lower phenol concentration. Ionising treatments also increased significantly (p≤0.05) the phenylalanine ammonia-lyase (PAL) activity. The observation of mushrooms cellular membranes, by electronic microscopy, revealed a better preserved integrity in I- than in I+. It is thus assumed that the browning effect observed in I+ was caused by both the decompartimentation of vacuolar phenol and by the entry of molecular oxygen into the cell cytoplasm. The synergetic effect of the residual active PPO and the molecular oxygen, in contact with the phenols, allowed an increased oxidation rate and, therefore, a more pronounced browning in I+ than in I-

  1. Concentration and Physicochemical Properties of Chitosan Derivatives Determine the Induction of Defense Responses in Roots and Leaves of Tobacco (Nicotiana tabacum Plants

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    Alejandro B. Falcon-Rodriguez

    2009-01-01

    Full Text Available Problem statement: The chitosan derivatives promote diverse defensive responses in plants, which are affected by chitosan chemical features and concentration. Glucanase (EC 3.2.1.6, Phenylalanine Ammonia-Lyase (PAL, EC 4.3.1.5 and peroxidase (POD, EC 1.11.1.6 are key enzymes in tobacco defense responses. Thus, the aim of this study was to know the behavior of their enzymatic activity in leaves and roots of whole tobacco plants, previously elicited with chitosan derivatives of different molecular weight and acetylating degree. Approach: 25 day-old tobacco plants were treated with three chitosan derivatives (CH- 63, CH-88 and OLG of different chemical features. True leaves and roots were sampled after three, six, nine and 12 days post-treatment for further evaluation of the enzymatic activities. Results: Chitosan treatments increased the activity of all three studied enzymes depending on the concentration and chemical feature of the derivative. The highest enzymatic activities with polymers occurred at 1 g L-1 while the oligochitosan mixture achieved good enzymatic levels as compared to controls from 0.1 g L-1 onwards. The Degree of Acetylation (DA affected PAL activity; a more acetylated polymer induced a higher activity than a less acetylated one. However, the low levels of acetylation favored POD activity. The systemic induction of enzymatic activities was detected in leaves of treated plants after root application. The effect of the acetylation degree was systemically transmitted to the leaves by POD, but not by PAL activity; so the transmission of the acetylating degree influence beyond the tissue directly elicited by chitosan polymer depended on each enzymatic response tested. Conclusion: This study proved that various chitosan derivatives induced and raised lasting β-1,3-glucanase, PAL and POD activities in tobacco leaves and roots as local or systemic responses, which could lead to the

  2. A De novo Transcriptomic Approach to Identify Flavonoids and Anthocyanins "Switch-Off" in Olive (Olea europaea L.) Drupes at Different Stages of Maturation.

    Science.gov (United States)

    Iaria, Domenico L; Chiappetta, Adriana; Muzzalupo, Innocenzo

    2015-01-01

    Highlights A de novo transcriptome reconstruction of olive drupes was performed in two genotypesGene expression was monitored during drupe development in two olive cultivarsTranscripts involved in flavonoid and anthocyanin pathways were analyzed in Cassanese and Leucocarpa cultivarsBoth cultivar and developmental stage impact gene expression in Olea europaea fruits. During ripening, the fruits of the olive tree (Olea europaea L.) undergo a progressive chromatic change characterized by the formation of a red-brown "spot" which gradually extends on the epidermis and in the innermost part of the mesocarp. This event finds an exception in the Leucocarpa cultivar, in which we observe a destabilized equilibrium between the metabolisms of chlorophyll and other pigments, particularly the anthocyanins whose switch-off during maturation promotes the white coloration of fruits. Despite its importance, genomic information on the olive tree is still lacking. Different RNA-seq libraries were generated from drupes of "Leucocarpa" and "Cassanese" olive genotypes, sampled at 100 and 130 days after flowering (DAF), and were used in order to identify transcripts involved in the main phenotypic changes of fruits during maturation and their corresponding expression patterns. A total of 103,359 transcripts were obtained and 3792 and 3064 were differentially expressed in "Leucocarpa" and "Cassanese" genotypes, respectively, during 100-130 DAF transition. Among them flavonoid and anthocyanin related transcripts such as phenylalanine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate-CoA ligase (4CL), chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), flavonol 3'-hydrogenase (F3'H), flavonol 3'5 '-hydrogenase (F3'5'H), flavonol synthase (FLS), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), UDP-glucose:anthocianidin: flavonoid glucosyltransferase (UFGT) were identified. These results contribute to reducing the current gap in

  3. Effect of seed treatment by cold plasma on the resistance of tomato to Ralstonia solanacearum (Bacterial Wilt.

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    Jiafeng Jiang

    Full Text Available This study investigated the effect of cold plasma seed treatment on tomato bacterial wilt, caused by Ralstonia solanacearum (R. solanacearum, and the regulation of resistance mechanisms. The effect of cold plasma of 80W on seed germination, plant growth, nutrient uptake, disease severity, hydrogen peroxide (H2O2 concentration and activities of peroxidase (POD; EC 1.11.1.7, polyphenol oxidase (PPO; EC 1.10.3.2 and phenylalanine ammonia lyase (PAL; EC 4.3.1.5 were examined in tomato plants. Plasma treatment increased tomato resistance to R. solanacearum with an efficacy of 25.0%. Plasma treatment significantly increased both germination and plant growth in comparison with the control treatment, and plasma-treated plants absorbed more calcium and boron than the controls. In addition, H2O2 levels in treated plants rose faster and reached a higher peak, at 2.579 µM gFW-1, 140% greater than that of the control. Activities of POD (421.3 U gFW-1, PPO (508.8 U gFW-1 and PAL (707.3 U gFW-1 were also greater in the treated plants than in the controls (103.0 U gFW-1, 166.0 U gFW-1 and 309.4 U gFW-1, respectively. These results suggest that plasma treatment affects the regulation of plant growth, H2O2 concentration, and POD, PPO and PAL activity in tomato, resulting in an improved resistance to R. solanacearum. Consequently, cold plasma seed treatment has the potential to control tomato bacterial wilt caused by R. solanacearum.

  4. Response dynamics of three defense related enzymes in cotton leaves to the interactive stress of Helicoverpa armigera (Hübner) herbivory and omethoate application

    Institute of Scientific and Technical Information of China (English)

    SHA Pin-jie; FAN Yin-jun; WANG Zhi-chao; SHI Xue-yan

    2015-01-01

    In order to explore the response dynamics of the activities of defense related enzymes in cotton leaves towards the inter-active stress of Helicoverpa armigera herbivory and omethoate application, the activities of phenylalanine ammonia-lyase (PAL), lipoxygenase (LOX), and polyphenol oxidase (PPO) were examined from 6 to 126 h after cotton leaves were treated 12 h of H. armigera herbivory, and then sprayed with 800 mg L–1 omethoate. The results showed that the changes in the activities of PAL, LOX and PPO that occured under the interactive stress of H. armigera herbivory and omethoate application relfected the interactive effects of the two stresses on cotton defense. The similarity between the response dynamics of PAL, LOX, and PPO activities in cotton leaves under the interactive stress and that under H. armigera herbivory treatment alone showed that the induction of H. armigera herbivory on the activities of PAL, LOX and PPO in cotton leaves played a leading role in the interactive effects, and the effect of omethoate application played only a minor role. A joint factor analysis was performed according to a method which has been used to analyze the joint toxicity of pesticides;this analysis sought to clarify if there was a synergistic, antagonistic, or additive effect on PAL, LOX, and PPO activity in cotton leaves resulting from the interactive H. armigera herbivory and omethoate treatment. In the interactive effect on the response of PAL activity in cotton leaves, antagonistic effects of the omethoate application towards H. armigera herbivory were observed at 6 and 12 h. Synergistic effects were then observed at 18 and 30 h. Antagonistic effects were observed from 54 to 78 h and syn-ergistic effects were ifnal y observed at 126 h. The correlation between H. armigera herbivory and omethoate application in the interactive effect on cotton defense responses of LOX activity also lfuctuated from synergism to antagonism during the time course. In the interactive

  5. Stone formation in peach fruit exhibits spatial coordination of the lignin and flavonoid pathways and similarity to Arabidopsis dehiscence

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    Piagnani M Claudia

    2010-02-01

    Full Text Available Abstract Background Lignification of the fruit endocarp layer occurs in many angiosperms and plays a critical role in seed protection and dispersal. This process has been extensively studied with relationship to pod shatter or dehiscence in Arabidopsis. Dehiscence is controlled by a set of transcription factors that define the fruit tissue layers and whether or not they lignify. In contrast, relatively little is known about similar processes in other plants such as stone fruits which contain an extremely hard lignified endocarp or stone surrounding a single seed. Results Here we show that lignin deposition in peach initiates near the blossom end within the endocarp layer and proceeds in a distinct spatial-temporal pattern. Microarray studies using a developmental series from young fruits identified a sharp and transient induction of phenylpropanoid, lignin and flavonoid pathway genes concurrent with lignification and subsequent stone hardening. Quantitative polymerase chain reaction studies revealed that specific phenylpropanoid (phenylalanine ammonia-lyase and cinnamate 4-hydroxylase and lignin (caffeoyl-CoA O-methyltransferase, peroxidase and laccase pathway genes were induced in the endocarp layer over a 10 day time period, while two lignin genes (p-coumarate 3-hydroxylase and cinnamoyl CoA reductase were co-regulated with flavonoid pathway genes (chalcone synthase, dihydroflavanol 4-reductase, leucoanthocyanidin dioxygen-ase and flavanone-3-hydrosylase which were mesocarp and exocarp specific. Analysis of other fruit development expression studies revealed that flavonoid pathway induction is conserved in the related Rosaceae species apple while lignin pathway induction is not. The transcription factor expression of peach genes homologous to known endocarp determinant genes in Arabidopsis including SHATTERPROOF, SEEDSTCK and NAC SECONDARY WALL THICENING PROMOTING FACTOR 1 were found to be specifically expressed in the endocarp while the

  6. Naringenin inhibits the growth and stimulates the lignification of soybean root

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    Graciene de Souza Bido

    2010-06-01

    Full Text Available The flavanone naringenin, an intermediate in flavonoid biosynthesis, was tested for its effect on root growth, phenylalanine ammonia-lyase (PAL and peroxidase (POD activities, as well as phenolic compounds and lignin contents in soybean (Glycine max L. Merrill seedlings. Three-day-old seedlings were cultivated in half-strength Hoagland nutrient solution (pH 6.0, with or without 0.1 to 0.4 mM naringenin in a growth chamber (25°C, 12-h photoperiod, irradiance of 280 µmol m-2 s-1 for 24 h. Inhibitory effects on root growth (length, weight, cell viability, PAL and soluble POD activities were detected after naringenin treatments. These effects were associated with stimulatory activity of the cell wall-bound POD followed by an increase in the lignin contents, suggesting that naringenin-induced inhibition in soybean roots could be due to the lignification process.Os efeitos de naringenina, um intermediário da biossíntese de flavonóides, foram avaliados sobre o crescimento das raízes, as atividades da fenilalanina amônia liase (PAL e peroxidases, bem como sobre os teores de compostos fenólicos e de lignina em plântulas de soja (Glycine max L. Merrill. Plântulas de três dias foram cultivadas em solução nutritiva de Hoagland, meia-força (pH 6,0, contendo ou não, naringenina 0,1 a 0,4 mM, em uma câmara de germinação (25°C, fotoperíodo de 12 h, 280 µmol m-2 s-1 durante 24 h. Efeitos inibitórios no crescimento das raízes (comprimento, massa e viabilidade celular e nas atividades da PAL e POD solúvel foram constatados após os tratamentos com naringenina. Estes efeitos foram associados com atividade estimulatória da POD ligada à parede celular, seguido por aumento nos teores de lignina, sugerindo que a inibição do crescimento das raízes pode ser devido ao processo de lignificação.

  7. Combined effect of water loss and wounding stress on gene activation of metabolic pathways associated with phenolic biosynthesis in carrot

    Science.gov (United States)

    Becerra-Moreno, Alejandro; Redondo-Gil, Mónica; Benavides, Jorge; Nair, Vimal; Cisneros-Zevallos, Luis; Jacobo-Velázquez, Daniel A.

    2015-01-01

    The application of postharvest abiotic stresses is an effective strategy to activate the primary and secondary metabolism of plants inducing the accumulation of antioxidant phenolic compounds. In the present study, the effect of water stress applied alone and in combination with wounding stress on the activation of primary (shikimic acid) and secondary (phenylpropanoid) metabolic pathways related with the accumulation of phenolic compound in plants was evaluated. Carrot (Daucus carota) was used as model system for this study, and the effect of abiotic stresses was evaluated at the gene expression level and on the accumulation of metabolites. As control of the study, whole carrots were stored under the same conditions. Results demonstrated that water stress activated the primary and secondary metabolism of carrots, favoring the lignification process. Likewise, wounding stress induced higher activation of the primary and secondary metabolism of carrots as compared to water stress alone, leading to higher accumulation of shikimic acid, phenolic compounds, and lignin. Additional water stress applied on wounded carrots exerted a synergistic effect on the wound-response at the gene expression level. For instance, when wounded carrots were treated with water stress, the tissue showed 20- and 14-fold increases in the relative expression of 3-deoxy-D-arabino-heptulosanate synthase and phenylalanine ammonia-lyase genes, respectively. However, since lignification was increased, lower accumulation of phenolic compounds was detected. Indicatively, at 48 h of storage, wounded carrots treated with water stress showed ~31% lower levels of phenolic compounds and ~23% higher lignin content as compared with wounded controls. In the present study, it was demonstrated that water stress is one of the pivotal mechanism of the wound-response in carrot. Results allowed the elucidation of strategies to induce the accumulation of specific primary or secondary metabolites when plants are

  8. Combined effect of water loss and wounding stress on gene activation of metabolic pathways associated with phenolic biosynthesis in carrot.

    Science.gov (United States)

    Becerra-Moreno, Alejandro; Redondo-Gil, Mónica; Benavides, Jorge; Nair, Vimal; Cisneros-Zevallos, Luis; Jacobo-Velázquez, Daniel A

    2015-01-01

    The application of postharvest abiotic stresses is an effective strategy to activate the primary and secondary metabolism of plants inducing the accumulation of antioxidant phenolic compounds. In the present study, the effect of water stress applied alone and in combination with wounding stress on the activation of primary (shikimic acid) and secondary (phenylpropanoid) metabolic pathways related with the accumulation of phenolic compound in plants was evaluated. Carrot (Daucus carota) was used as model system for this study, and the effect of abiotic stresses was evaluated at the gene expression level and on the accumulation of metabolites. As control of the study, whole carrots were stored under the same conditions. Results demonstrated that water stress activated the primary and secondary metabolism of carrots, favoring the lignification process. Likewise, wounding stress induced higher activation of the primary and secondary metabolism of carrots as compared to water stress alone, leading to higher accumulation of shikimic acid, phenolic compounds, and lignin. Additional water stress applied on wounded carrots exerted a synergistic effect on the wound-response at the gene expression level. For instance, when wounded carrots were treated with water stress, the tissue showed 20- and 14-fold increases in the relative expression of 3-deoxy-D-arabino-heptulosanate synthase and phenylalanine ammonia-lyase genes, respectively. However, since lignification was increased, lower accumulation of phenolic compounds was detected. Indicatively, at 48 h of storage, wounded carrots treated with water stress showed ~31% lower levels of phenolic compounds and ~23% higher lignin content as compared with wounded controls. In the present study, it was demonstrated that water stress is one of the pivotal mechanism of the wound-response in carrot. Results allowed the elucidation of strategies to induce the accumulation of specific primary or secondary metabolites when plants are

  9. Combined effect of water loss and wounding stress on gene activation of metabolic pathways associated with phenolic biosynthesis in carrot

    Directory of Open Access Journals (Sweden)

    Alejandro eBecerra-Moreno

    2015-10-01

    Full Text Available Abstract: The application of postharvest abiotic stresses is an effective strategy to activate the primary and secondary metabolism of plants inducing the accumulation of antioxidant phenolic compounds. In the present study, the effect of water stress applied alone and in combination with wounding stress on the activation of primary (shikimic acid and secondary (phenylpropanoid metabolic pathways related with the accumulation of phenolic compound in plants was evaluated. Carrot (Daucus carota was used as model system for this study, and the effect of abiotic stresses was evaluated at the gene expression level and on the accumulation of metabolites. As control of the study, whole carrots were stored under the same conditions. Results demonstrated that water stress activated the primary and secondary metabolism of carrots, favoring the lignification process. Likewise, wounding stress induced higher activation of the primary and secondary metabolism of carrots as compared to water stress alone, leading to higher accumulation of shikimic acid, phenolic compounds and lignin. Additional water stress applied on wounded carrots exerted a synergistic effect on the wound-response at the gene expression level. For instance, when wounded carrots were treated with water stress, the tissue showed 20- and 14-fold increases in the relative expression of 3-deoxy-D-arabino-heptulosanate synthase and phenylalanine ammonia-lyase genes, respectively. However, since lignification was increased, lower accumulation of phenolic compounds was detected. Indicatively, at 48 h of storage, wounded carrots treated with water stress showed ~31% lower levels of phenolic compounds and ~23% higher lignin content as compared with wounded controls. In the present study, it was demonstrated that water stress is one of the pivotal mechanism of the wound-response in carrot. Results allowed the elucidation of strategies to induce the accumulation of specific primary or secondary

  10. Physiological mechanisms involved in resistance to cotton verticillium wilt induced by AM fungi

    Institute of Scientific and Technical Information of China (English)

    LIU Bing-jiang; LIU Run-jin

    2004-01-01

    @@ It was proved that arbuscular mycorrhizal (AM) fungi played an important role in increasing plant resistance to soilborne pathogens, especially when plants were pre-inoculated with AM fungi.Mechanisms involved in this phenomenon are not yet well understood. On the basis of the former experiment results in our lab, effects of AM fungi on cotton Verticillium wilt and the mechanisms of increasing disease resisitance by the tested fungi were studied in pot culture under greenhouse conditions. Two cotton cutivars Litai 8 and 86-1 which are susceptible to Verticillium dahliae were pre-inoculated with Glomus fasiculatum, and Gigaspora margarita, then inoculated with the strain of Verticillium dahliae, namely "An-Yang" (belong to intermediate virulent type) 30 days after the former inoculation. Results showed that AM fungi could improve the growth and development of cotton plants, increase plants dry mass, decrease incidence and disease index of Verticillium wilt of cotton plants, inhibit the infection and development of V. dahliae to different extent in the rhizosphere of cotton pre-inoculated with AM fungi, while the colonization and spore numbers of AM fungi were not reduced significantly by this pathogen. The defence enzymes, such as phenylalanine ammonia-lyase (PAL), chitinase, β-1, 3-glucanase, peroxidase, polyphenoloxidase (PPO) were induced, and their activities and peak increased by AM fungi in roots and leaves, and the increasing speed and peak of the enzyme activity were higher in treatment with AM fungus preinoculation than the inoculation with only V. dahliae, which suggested that defense response was activated by AM fungi, and then made the cotton to react strongly and rapidly to the infection of V. dahliae. In addition, AM fungi decreased the content of malondiadehyde (MDA) in cotton roots and leaves,protected membrane system and alleviated the damage caused by the pathogen. The AM fungus,Glomus fasiculatum showed the superior effects of biological

  11. Kaolin Foliar Application Has a Stimulatory Effect on Phenylpropanoid and Flavonoid Pathways in Grape Berries.

    Science.gov (United States)

    Conde, Artur; Pimentel, Diana; Neves, Andreia; Dinis, Lia-Tânia; Bernardo, Sara; Correia, Carlos M; Gerós, Hernâni; Moutinho-Pereira, José

    2016-01-01

    Drought, elevated air temperature, and high evaporative demand are increasingly frequent during summer in grape growing areas like the Mediterranean basin, limiting grapevine productivity and berry quality. The foliar exogenous application of kaolin, a radiation-reflecting inert mineral, has proven effective in mitigating the negative impacts of these abiotic stresses in grapevine and other fruit crops, however, little is known about its influence on the composition of the grape berry and on key molecular mechanisms and metabolic pathways notably important for grape berry quality parameters. Here, we performed a thorough molecular and biochemical analysis to assess how foliar application of kaolin influences major secondary metabolism pathways associated with berry quality-traits, leading to biosynthesis of phenolics and anthocyanins, with a focus on the phenylpropanoid, flavonoid (both flavonol- and anthocyanin-biosynthetic) and stilbenoid pathways. In grape berries from different ripening stages, targeted transcriptional analysis by qPCR revealed that several genes involved in these pathways-VvPAL1, VvC4H1, VvSTSs, VvCHS1, VvFLS1, VvDFR, and VvUFGT-were more expressed in response to the foliar kaolin treatment, particularly in the latter maturation phases. In agreement, enzymatic activities of phenylalanine ammonia lyase (PAL), flavonol synthase (FLS), and UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT) were about two-fold higher in mature or fully mature berries from kaolin-treated plants, suggesting regulation also at a transcriptional level. The expression of the glutathione S-transferase VvGST4, and of the tonoplast anthocyanin transporters VvMATE1 and VvABCC1 were also all significantly increased at véraison and in mature berries, thus, when anthocyanins start to accumulate in the vacuole, in agreement with previously observed higher total concentrations of phenolics and anthocyanins in berries from kaolin-treated plants, especially at full maturity

  12. Relationship Between Anthocyanin Biosynthesis and Related Enzymes Activity in Pyrus pyrifolia Mantianhong and Its Bud Sports Aoguan

    Institute of Scientific and Technical Information of China (English)

    FENG Shou-qian; CHEN Xue-sen; ZHANG Chun-yu; LIU Xiao-jing; LIU Zun-chun; WANG Hai-bo; WANG Yan-ling; ZHOU Chao-hua

    2008-01-01

    The aim of this article is to study the relationship between biosynthesis of anthocyanin and activities of phenylalanine ammonia lyase (PAL), chalcone ismoerase (CHI) enzymes in Pyrus pyrifolia. Changes in the level of anthocyanin and the activities of enzymes of anthocyanin biosynthesis including PAL, CH1 were studied in the pericarp of Pyrus pyrifolia Aoguan and Mantianhong during the period of pigment formation. Bagging treatment was also carried out to manipulate the synthesis of anthocyanin and the activities of related enzymes during the period of pigment formation. The results demonstrated that the level of anthocyanin of Aoguan was higher than that of Mantianhong. However, the content of anthocyanins has the similar changing trend in Aoguan and Mantianhong, highest anthocyanin concentrations of two varieties appeared in immature fruit and faded toward harvest. Meanwhile, similar changing trends of activities of PAL and CHI were also observed in both varieties. Aoguan has a lower activity of PAL than Mantianhong, whereas activity of CHI in Aoguan was higher than that in Mantianhong. Activity of PAL decreased during the period of pigment formation and was apparently not limiting to color development, whereas CHI activity increased at the same period and was closely related to the synthesis of anthocyanin. The results of bagging treatment showed that bagging treatment inhibited the activity of CHI, as well as the synthesis of anthocyanin, whereas debagging enhanced both the activity of CHI and synthesis of anthocyanin. The activity of CHI in debagging Aoguan pericarp was higher than the untreated Aoguan. However, effect of bagging treatment toward PAL activity was not obvious. Anthocyanin of bagging treated Aoguan decreased toward harvest. The content of anthocyanin of Pyrus pyrifolia increased at the beginning of fruit coloration period and decreased toward fruit harvest. Activity of PAL was apparently not limiting to color development, whereas CHI activity

  13. An in silico assessment of gene function and organization of the phenylpropanoid pathway metabolic networks in Arabidopsis thaliana and limitations thereof

    Science.gov (United States)

    Costa, Michael A.; Collins, R. Eric; Anterola, Aldwin M.; Cochrane, Fiona C.; Davin, Laurence B.; Lewis, Norman G.

    2003-01-01

    The Arabidopsis genome sequencing in 2000 gave to science the first blueprint of a vascular plant. Its successful completion also prompted the US National Science Foundation to launch the Arabidopsis 2010 initiative, the goal of which is to identify the function of each gene by 2010. In this study, an exhaustive analysis of The Institute for Genomic Research (TIGR) and The Arabidopsis Information Resource (TAIR) databases, together with all currently compiled EST sequence data, was carried out in order to determine to what extent the various metabolic networks from phenylalanine ammonia lyase (PAL) to the monolignols were organized and/or could be predicted. In these databases, there are some 65 genes which have been annotated as encoding putative enzymatic steps in monolignol biosynthesis, although many of them have only very low homology to monolignol pathway genes of known function in other plant systems. Our detailed analysis revealed that presently only 13 genes (two PALs, a cinnamate-4-hydroxylase, a p-coumarate-3-hydroxylase, a ferulate-5-hydroxylase, three 4-coumarate-CoA ligases, a cinnamic acid O-methyl transferase, two cinnamoyl-CoA reductases) and two cinnamyl alcohol dehydrogenases can be classified as having a bona fide (definitive) function; the remaining 52 genes currently have undetermined physiological roles. The EST database entries for this particular set of genes also provided little new insight into how the monolignol pathway was organized in the different tissues and organs, this being perhaps a consequence of both limitations in how tissue samples were collected and in the incomplete nature of the EST collections. This analysis thus underscores the fact that even with genomic sequencing, presumed to provide the entire suite of putative genes in the monolignol-forming pathway, a very large effort needs to be conducted to establish actual catalytic roles (including enzyme versatility), as well as the physiological function(s) for each member

  14. Kaolin Foliar Application Has a Stimulatory Effect on Phenylpropanoid and Flavonoid Pathways in Grape Berries

    Science.gov (United States)

    Conde, Artur; Pimentel, Diana; Neves, Andreia; Dinis, Lia-Tânia; Bernardo, Sara; Correia, Carlos M.; Gerós, Hernâni; Moutinho-Pereira, José

    2016-01-01

    Drought, elevated air temperature, and high evaporative demand are increasingly frequent during summer in grape growing areas like the Mediterranean basin, limiting grapevine productivity and berry quality. The foliar exogenous application of kaolin, a radiation-reflecting inert mineral, has proven effective in mitigating the negative impacts of these abiotic stresses in grapevine and other fruit crops, however, little is known about its influence on the composition of the grape berry and on key molecular mechanisms and metabolic pathways notably important for grape berry quality parameters. Here, we performed a thorough molecular and biochemical analysis to assess how foliar application of kaolin influences major secondary metabolism pathways associated with berry quality-traits, leading to biosynthesis of phenolics and anthocyanins, with a focus on the phenylpropanoid, flavonoid (both flavonol- and anthocyanin-biosynthetic) and stilbenoid pathways. In grape berries from different ripening stages, targeted transcriptional analysis by qPCR revealed that several genes involved in these pathways—VvPAL1, VvC4H1, VvSTSs, VvCHS1, VvFLS1, VvDFR, and VvUFGT—were more expressed in response to the foliar kaolin treatment, particularly in the latter maturation phases. In agreement, enzymatic activities of phenylalanine ammonia lyase (PAL), flavonol synthase (FLS), and UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT) were about two-fold higher in mature or fully mature berries from kaolin-treated plants, suggesting regulation also at a transcriptional level. The expression of the glutathione S-transferase VvGST4, and of the tonoplast anthocyanin transporters VvMATE1 and VvABCC1 were also all significantly increased at véraison and in mature berries, thus, when anthocyanins start to accumulate in the vacuole, in agreement with previously observed higher total concentrations of phenolics and anthocyanins in berries from kaolin-treated plants, especially at full

  15. The effects of enhanced methionine synthesis on amino acid and anthocyanin content of potato tubers

    Directory of Open Access Journals (Sweden)

    Bánfalvi Zsófia

    2008-06-01

    Full Text Available Abstract Background Potato is a staple food in the diet of the world's population and also being used as animal feed. Compared to other crops, however, potato tubers are relatively poor in the essential amino acid, methionine. Our aim was to increase the methionine content of tubers by co-expressing a gene involved in methionine synthesis with a gene encoding a methionine-rich storage protein in potato plants. Results In higher plants, cystathionine γ-synthase (CgS is the first enzyme specific to methionine biosynthesis. We attempted to increase the methionine content of tubers by expressing the deleted form of the Arabidopsis CgS (CgSΔ90, which is not regulated by methionine, in potato plants. To increase the incorporation of free methionine into a storage protein the CgSΔ90 was co-transformed with the methionine-rich 15-kD β-zein. Results demonstrated a 2- to 6-fold increase in the free methionine content and in the methionine content of the zein-containing protein fraction of the transgenic tubers. In addition, in line with higher methionine content, the amounts of soluble isoleucine and serine were also increased. However, all of the lines with high level of CgSΔ90 expression were phenotypically abnormal showing severe growth retardation, changes in leaf architecture and 40- to 60% reduction in tuber yield. Furthermore, the colour of the transgenic tubers was altered due to the reduced amounts of anthocyanin pigments. The mRNA levels of phenylalanine ammonia-lyase (PAL, the enzyme catalysing the first step of anthocyanin synthesis, were decreased. Conclusion Ectopic expression of CgSΔ90 increases the methionine content of tubers, however, results in phenotypic aberrations in potato. Co-expression of the 15-kD β-zein with CgSΔ90 results in elevation of protein-bound methionine content of tubers, but can not overcome the phenotypical changes caused by CgSΔ90 and can not significantly improve the nutritional value of tubers. The level

  16. Exogenous application of pectin-derived oligosaccharides to grape berries modifies anthocyanin accumulation, composition and gene expression.

    Science.gov (United States)

    Villegas, Daniel; Handford, Michael; Alcalde, José Antonio; Perez-Donoso, Alonso

    2016-07-01

    Anthocyanins are secondary metabolites synthesized in grape berry skins via the phenylpropanoid pathway, with functions ranging from skin coloration to protection against pathogens or UV light. Accumulation of these compounds is highly variable depending on genetics, environmental factors and viticultural practices. Besides their biological functions, anthocyanins improve wine quality, as a high anthocyanin content in berries has a positive impact on the color, total phenolic concentration and, ultimately, the price of wine. The present work studies the effect of the pre-veraison application of pectin derived oligosaccharides (PDO) on the synthesis and accumulation of these compounds, and associates the changes observed with the expression of key genes in the phenylpropanoid pathways. To this end, pre-veraison Cabernet Sauvignon bunches were treated with PDO to subsequently determine total anthocyanin content, the anthocyanin profile (by HPLC-DAD) and gene expression (by qRT-PCR), using Ethrel and water treatments for comparison. The results show that PDO were as efficient as Ethrel in generating a significant rise in total anthocyanin content at 30 days after treatment (dat), compared with water treatments (1.32, 1.48 and 1.02 mg e.Mv-3G/g FW respectively) without any undesirable effect on berry size, soluble solids, tartaric acid concentration or pH. In addition, a significant alteration in the anthocyanin profile was observed. Specifically, a significant increase in the relative concentration of malvidin was observed for both PDO and Ethrel treatments, compared with water controls (52.8; 55.0 and 48.3%, respectively), with a significant rise in tri-hydroxylated forms and a fall in di-hydroxylated anthocyanins. The results of gene expression analyses suggest that the increment in total anthocyanin content is related to a short term increase in phenylalanine ammonia-lyase (PAL) expression, mediated by a decrease in MYB4A expression. A longer term increase in UDP

  17. Development and characterization of an oat TILLING-population and identification of mutations in lignin and β-glucan biosynthesis genes

    Directory of Open Access Journals (Sweden)

    Vivekanand Vivekanand

    2010-05-01

    Full Text Available Abstract Background Oat, Avena sativa is the sixth most important cereal in the world. Presently oat is mostly used as feed for animals. However, oat also has special properties that make it beneficial for human consumption and has seen a growing importance as a food crop in recent decades. Increased demand for novel oat products has also put pressure on oat breeders to produce new oat varieties with specific properties such as increased or improved β-glucan-, antioxidant- and omega-3 fatty acid levels, as well as modified starch and protein content. To facilitate this development we have produced a TILLING (Targeting Induced Local Lesions IN Genomes population of the spring oat cultivar SW Belinda. Results Here a population of 2600 mutagenised M2 lines, producing 2550 M3 seed lots were obtained. The M2 population was initially evaluated by visual inspection and a number of different phenotypes were seen ranging from dwarfs to giants, early flowering to late flowering, leaf morphology and chlorosis. Phloroglucinol/HCl staining of M3 seeds, obtained from 1824 different M2 lines, revealed a number of potential lignin mutants. These were later confirmed by quantitative analysis. Genomic DNA was prepared from the M2 population and the mutation frequency was determined. The estimated mutation frequency was one mutation per 20 kb by RAPD-PCR fingerprinting, one mutation per 38 kb by MALDI-TOF analysis and one mutation per 22.4 kb by DNA sequencing. Thus, the overall mutation frequency in the population is estimated to be one mutation per 20-40 kb, depending on if the method used addressed the whole genome or specific genes. During the investigation, 6 different mutations in the phenylalanine ammonia-lyase (AsPAL1 gene and 10 different mutations in the cellulose synthase-like (AsCslF6 β-glucan biosynthesis gene were identified. Conclusion The oat TILLING population produced in this work carries, on average, hundreds of mutations in every individual

  18. Expression of cell wall related genes in basal and ear internodes of silking brown-midrib-3, caffeic acid O-methyltransferase (COMT down-regulated, and normal maize plants

    Directory of Open Access Journals (Sweden)

    Martinant Jean-Pierre

    2008-06-01

    Full Text Available Abstract Background Silage maize is a major forage and energy resource for cattle feeding, and several studies have shown that lignin content and structure are the determining factors in forage maize feeding value. In maize, four natural brown-midrib mutants have modified lignin content, lignin structure and cell wall digestibility. The greatest lignin reduction and the highest cell wall digestibility were observed in the brown-midrib-3 (bm3 mutant, which is disrupted in the caffeic acid O-methyltransferase (COMT gene. Results Expression of cell wall related genes was investigated in basal and ear internodes of normal, COMT antisens (AS225, and bm3 maize plants of the INRA F2 line. A cell wall macro-array was developed with 651 gene specific tags of genes specifically involved in cell wall biogenesis. When comparing basal (older lignifying and ear (younger lignifying internodes of the normal line, all genes known to be involved in constitutive monolignol biosynthesis had a higher expression in younger ear internodes. The expression of the COMT gene was heavily reduced, especially in the younger lignifying tissues of the ear internode. Despite the fact that AS225 transgene expression was driven only in sclerenchyma tissues, COMT expression was also heavily reduced in AS225 ear and basal internodes. COMT disruption or down-regulation led to differential expressions of a few lignin pathway genes, which were all over-expressed, except for a phenylalanine ammonia-lyase gene. More unexpectedly, several transcription factor genes, cell signaling genes, transport and detoxification genes, genes involved in cell wall carbohydrate metabolism and genes encoding cell wall proteins, were differentially expressed, and mostly over-expressed, in COMT-deficient plants. Conclusion Differential gene expressions in COMT-deficient plants highlighted a probable disturbance in cell wall assembly. In addition, the gene expressions suggested modified chronology of the

  19. A De novo Transcriptomic Approach to Identify Flavonoids and Anthocyanins “Switch-Off” in Olive (Olea europaea L.) Drupes at Different Stages of Maturation

    Science.gov (United States)

    Iaria, Domenico L.; Chiappetta, Adriana; Muzzalupo, Innocenzo

    2016-01-01

    Highlights A de novo transcriptome reconstruction of olive drupes was performed in two genotypesGene expression was monitored during drupe development in two olive cultivarsTranscripts involved in flavonoid and anthocyanin pathways were analyzed in Cassanese and Leucocarpa cultivarsBoth cultivar and developmental stage impact gene expression in Olea europaea fruits. During ripening, the fruits of the olive tree (Olea europaea L.) undergo a progressive chromatic change characterized by the formation of a red-brown “spot” which gradually extends on the epidermis and in the innermost part of the mesocarp. This event finds an exception in the Leucocarpa cultivar, in which we observe a destabilized equilibrium between the metabolisms of chlorophyll and other pigments, particularly the anthocyanins whose switch-off during maturation promotes the white coloration of fruits. Despite its importance, genomic information on the olive tree is still lacking. Different RNA-seq libraries were generated from drupes of “Leucocarpa” and “Cassanese” olive genotypes, sampled at 100 and 130 days after flowering (DAF), and were used in order to identify transcripts involved in the main phenotypic changes of fruits during maturation and their corresponding expression patterns. A total of 103,359 transcripts were obtained and 3792 and 3064 were differentially expressed in “Leucocarpa” and “Cassanese” genotypes, respectively, during 100–130 DAF transition. Among them flavonoid and anthocyanin related transcripts such as phenylalanine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate-CoA ligase (4CL), chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), flavonol 3′-hydrogenase (F3′H), flavonol 3′5 ′-hydrogenase (F3′5′H), flavonol synthase (FLS), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), UDP-glucose:anthocianidin: flavonoid glucosyltransferase (UFGT) were identified. These results contribute

  20. The Ve-mediated resistance response of the tomato to Verticillium dahliae involves H2O2, peroxidase and lignins and drives PAL gene expression

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    Merino Fuencisla

    2010-10-01

    Full Text Available Abstract Background Verticillium dahliae is a fungal pathogen that infects a wide range of hosts. The only known genes for resistance to Verticillium in the Solanaceae are found in the tomato (Solanum lycopersicum Ve locus, formed by two linked genes, Ve1 and Ve2. To characterize the resistance response mediated by the tomato Ve gene, we inoculated two nearly isogenic tomato lines, LA3030 (ve/ve and LA3038 (Ve/Ve, with V. dahliae. Results We found induction of H2O2 production in roots of inoculated plants, followed by an increase in peroxidase activity only in roots of inoculated resistant plants. Phenylalanine-ammonia lyase (PAL activity was also increased in resistant roots 2 hours after inoculation, while induction of PAL activity in susceptible roots was not seen until 48 hours after inoculation. Phenylpropanoid metabolism was also affected, with increases in ferulic acid, p-coumaric acid, vanillin and p-hydroxybenzaldehyde contents in resistant roots after inoculation. Six tomato PAL cDNA sequences (PAL1 - PAL6 were found in the SolGenes tomato EST database. RT-PCR analysis showed that these genes were expressed in all organs of the plant, albeit at different levels. Real-time RT-PCR indicated distinct patterns of expression of the different PAL genes in V. dahliae-inoculated roots. Phylogenetic analysis of 48 partial PAL cDNAs corresponding to 19 plant species grouped angiosperm PAL sequences into four clusters, suggesting functional differences among the six tomato genes, with PAL2 and PAL6 presumably involved in lignification, and the remaining PAL genes implicated in other biological processes. An increase in the synthesis of lignins was found 16 and 28 days after inoculation in both lines; this increase was greater and faster to develop in the resistant line. In both resistant and susceptible inoculated plants, an increase in the ratio of guaiacyl/syringyl units was detected 16 days after inoculation, resulting from the lowered amount

  1. Continuous production of L-phenylalanine by Rhodotorula glutinis immobilized cells using a column reactor.

    Science.gov (United States)

    El-Batal, Ahmed I

    2002-01-01

    Studies have been conducted on L-phenylalanine (L-Phe) production and phenylalanine ammonia lyase (PAL) stabilization in the presence of several optimum effectors and reducing agents under bioconversion of transcinnamic acid (t-CA) conditions during repeated batch operations. L-Phe production was maximized and reuseability of PAL catalyst was extended to eight consecutive cycles (repeated batches) in the presence of optimum effectors (glutamic acid, polyethylene glycol and glycerol), thioglycolic acid and sparging with nitrogen gas. These best optimum bioconversion conditions desensitize the PAL catalyst to substantially elevated higher substrate t-CA concentrations and inhibit inactivation of PAL enzyme over longer reaction periods compared to the control. The fed batch mode operation of bioconversion of total t-CA (300 mM) to L-Phe was superior (65.2%, conversion), comparing with conventional batch and repeated batch (58.4%, conversion) operations after 120 h. Gamma irradiation process was employed to polymerize and crosslink polyvinyl alcohol (PVA) with N,N'-methylene-bisacrylamide (BIS) agent. The use of immobilized PAL biocatalyst containing cells in PVA-BIS copolymer gel carrier produced by radiation polymerization is obviously advantageous with regards to the yield of L-Phe which was increased in average 1.2-fold when compare to those obtained with free cells during optimum bioconversion process. When comparing the magnitudes of gamma irradiation effects on immobilized entrapped yeast cells in PVA-BIS copolymer gel carrier using scanning electron microscopy it was show that yeast cells were protected and capable to overcome these conditions and had normal shape and other features as free (unirradiated) intact yeast cells. Optimum conditions for continuous production of L-Phe by PVA-BIS copolymer carrier entrapped yeast cells in a packed bed column reactor in recycle fed-batch mode were investigated. Under these optimum conditions L-Phe accumulated to

  2. Biosynthesis of caffeic acid in Escherichia coli using its endogenous hydroxylase complex

    Directory of Open Access Journals (Sweden)

    Lin Yuheng

    2012-04-01

    Full Text Available Abstract Background Caffeic acid (3,4-dihydroxycinnamic acid is a natural phenolic compound derived from the plant phenylpropanoid pathway. Caffeic acid and its phenethyl ester (CAPE have attracted increasing attention for their various pharmaceutical properties and health-promoting effects. Nowadays, large-scale production of drugs or drug precursors via microbial approaches provides a promising alternative to chemical synthesis and extraction from plant sources. Results We first identified that an Escherichia coli native hydroxylase complex previously characterized as the 4-hydroxyphenylacetate 3-hydroxylase (4HPA3H was able to convert p-coumaric acid to caffeic acid efficiently. This critical enzymatic step catalyzed in plants by a membrane-associated cytochrome P450 enzyme, p-coumarate 3-hydroxylase (C3H, is difficult to be functionally expressed in prokaryotic systems. Moreover, the performances of two tyrosine ammonia lyases (TALs from Rhodobacter species were compared after overexpression in E. coli. The results indicated that the TAL from R. capsulatus (Rc possesses higher activity towards both tyrosine and L-dopa. Based on these findings, we further designed a dual pathway leading from tyrosine to caffeic acid consisting of the enzymes 4HPA3H and RcTAL. This heterologous pathway extended E. coli native tyrosine biosynthesis machinery and was able to produce caffeic acid (12.1 mg/L in minimal salt medium. Further improvement in production was accomplished by boosting tyrosine biosynthesis in E. coli, which involved the alleviation of tyrosine-induced feedback inhibition and carbon flux redirection. Finally, the titer of caffeic acid reached 50.2 mg/L in shake flasks after 48-hour cultivation. Conclusion We have successfully established a novel pathway and constructed an E. coli strain for the production of caffeic acid. This work forms a basis for further improvement in production, as well as opens the possibility of microbial synthesis

  3. Biochemical Mechanism of Resistance against Soybean Cyst Nematode Induced by Plant Growth Promoting Rhizobacteria in Soybean%根际促生菌诱导大豆抗大豆胞囊线虫的生化机理

    Institute of Scientific and Technical Information of China (English)

    段玉玺; 张禹; 朱晓峰; 刘大伟; 李颂; 陈立杰; 王媛媛

    2011-01-01

    为揭示由根际促生细菌[Sneb207(Bacillus megaterium),Sneb482(Bacillus megaterum)]诱导大豆抗大豆胞囊线虫(Heterodera glycines Inhinhe)的生化机理.使用菌株Sneb207、Sneb482发酵液包衣处理大豆种子,在豆苗三叶期时接种大豆胞囊线虫卵悬液,分别于接种后6、12、18、24、30 d取样,测定大豆根内防御酶系活性(PAL,PP0,POD)、总酚含量和几丁质酶活性的动态变化.结果表明:大豆种子经Sneb207、Sneb482发酵液处理后,根内PAL、PP0、POD活性较对照均表现上升趋势,总酚含量也有所提高.与菌株SneB482相比,菌株Sneb207表现出对大豆胞囊线虫病更好的诱导抗病潜力.%It has been a new research focus on biological control that the induction of disease resistance and growth response in plants is elicited by plant growth promoting rhizobacteria(PGPR). This study aimed to examine the biochemical mechanism of the resistance to soybean cyst nematode ( Heterodera glycines Ichinohe ) in soybean induced by PGPR [ Sneb207 ( Bacillus megaterium) and Sneb482 (Bacillus megaterium) ]. Seed bacterization with Sneb207 and Sneb482 were utilized in the experiment. The soybean plants were inoculated with eggs of soybean cyst nematode after soybean trefoil stage and the samples of roots were obtained 6,12,18,24 and 30 days later. Activities of plant resistance correlated enzymes including defense enzymes, namely phenylalanine ammonia-lyase (PAL), polyphenoloxidase (PPO), peroxidase (POD) and chitinase were measured, the content of total phenolics was also determined. The results showed that both the activities of PAL, PPO, POD,chitinase and the contents of total phenolics could be increased significantly by seed coating with fermentation liquid of plant growth promoting rhizobacteria (Sneb207, Sneb482) in the soybean roots than those in control. Sneb207 showed greater potential in induced resistance against soybean cyst nematode in the soybean plants than Sneb482.

  4. Physiological and biochemical aspects of the resistance of banana plants to Fusarium wilt potentiated by silicon.

    Science.gov (United States)

    Fortunato, Alessandro Antonio; Rodrigues, Fabrício Ávila; do Nascimento, Kelly Juliane Teles

    2012-10-01

    Silicon amendments to soil have resulted in a decrease of diseases caused by several soilborne pathogens affecting a wide number of crops. This study evaluated the physiological and biochemical mechanisms that may have increased resistance of banana to Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense, after treatment with silicon (Si) amendment. Plants from the Grand Nain (resistant to F. oxysporum f. sp. cubense) and "Maçã" (susceptible to F. oxysporum f. sp. cubense) were grown in plastic pots amended with Si at 0 or 0.39 g/kg of soil (-Si or +Si, respectively) and inoculated with race 1 of F. oxysporum f. sp. cubense. Relative lesion length (RLL) and asymptomatic fungal colonization in tissue (AFCT) were evaluated at 40 days after inoculation. Root samples were collected at different times after inoculation with F. oxysporum f. sp. cubense to determine the level of lipid peroxidation, expressed as equivalents of malondialdehyde (MDA), hydrogen peroxide (H(2)O(2)), pigments (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids), total soluble phenolics (TSP), and lignin-thioglycolic acid (LTGA) derivatives; the activities of the enzymes phenylalanine ammonia-lyases glucanases (PALs), peroxidases (POXs), polyphenoloxidases (PPOs), β-1,3-glucanases (GLUs), and chitinases (CHIs); and Si concentration in roots. Root Si concentration was significantly increased by 35.3% for the +Si treatment compared with the -Si treatment. For Grand Nain, the root Si concentration was significantly increased by 12.8% compared with "Maçã." Plants from Grand Nain and "Maçã" in the +Si treatment showed significant reductions of 40.0 and 57.2%, respectively, for RLL compared with the -Si treatment. For the AFCT, there was a significant reduction of 18.5% in the +Si treatment compared with the -Si treatment. The concentration of MDA significantly decreased for plants from Grand Nain and "Maçã" supplied with Si compared with the -Si treatment while the

  5. Glycosylation-mediated phenylpropanoid partitioning in Populus tremuloides cell cultures

    Directory of Open Access Journals (Sweden)

    Babst Benjamin A

    2009-12-01

    Full Text Available Abstract Background Phenylpropanoid-derived phenolic glycosides (PGs and condensed tannins (CTs comprise large, multi-purpose non-structural carbon sinks in Populus. A negative correlation between PG and CT concentrations has been observed in several studies. However, the molecular mechanism underlying the relationship is not known. Results Populus cell cultures produce CTs but not PGs under normal conditions. Feeding salicyl alcohol resulted in accumulation of salicins, the simplest PG, in the cells, but not higher-order PGs. Salicin accrual reflected the stimulation of a glycosylation response which altered a number of metabolic activities. We utilized this suspension cell feeding system as a model for analyzing the possible role of glycosylation in regulating the metabolic competition between PG formation, CT synthesis and growth. Cells accumulated salicins in a dose-dependent manner following salicyl alcohol feeding. Higher feeding levels led to a decrease in cellular CT concentrations (at 5 or 10 mM, and a negative effect on cell growth (at 10 mM. The competition between salicin and CT formation was reciprocal, and depended on the metabolic status of the cells. We analyzed gene expression changes between controls and cells fed with 5 mM salicyl alcohol for 48 hr, a time point when salicin accumulation was near maximum and CT synthesis was reduced, with no effect on growth. Several stress-responsive genes were up-regulated, suggestive of a general stress response in the fed cells. Salicyl alcohol feeding also induced expression of genes associated with sucrose catabolism, glycolysis and the Krebs cycle. Transcript levels of phenylalanine ammonia lyase and most of the flavonoid pathway genes were reduced, consistent with down-regulated CT synthesis. Conclusions Exogenous salicyl alcohol was readily glycosylated in Populus cell cultures, a process that altered sugar utilization and phenolic partitioning in the cells. Using this system, we

  6. ASCORBIC ACID CONTROLS MYCOSPHAERELLA GRAMINICOLA IN BREAD AND DURUM WHEAT THROUGH DIRECT EFFECT ON THE PATHOGEN AND INDIRECT ACTION VIA PLANT DEFENCE.

    Science.gov (United States)

    Somai-Jemmali, L; Magnin-Robert, M; Randoux, B; Siah, A; Tisserant, B; Halama, P; Reignault, Ph; Hamada, W

    2015-01-01

    increased at the penetration site in AA-treated leaves. In addition, AA treatment impacted the phenylpropanoid pathway through the induction of phenylalanine ammonia lyase activity. These results show that, in our conditions, AA both presents an antifungal activity and triggers several plant defences in wheat and suggest its use to control M. graminicola on both DW and BW. PMID:27141744

  7. Allocation of carbon to growth and secondary metabolites in birch seedlings under UV-B radiation and CO{sub 2} exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lavola, A.; Julkunen-Tiitto, R. [Univ. of Joensuu, Dept. of Biology, Joensuu (Finland); Rosa, T.M. de la [Univ. of Joensuu, Faculty of Forestry, Joensuu (Finland)

    2000-07-01

    In plants, the allocation of carbon to secondary metabolites has been shown to be determined by both the availability of resources (e.g., CO{sub 2} concentration) and by specific stress factors (e.g., ultraviolet [UV]-radiation). It has been suggested that, in combination, CO{sub 2} and UV-B radiation may differentially affect plant growth and morphogenic parameters, and elevated CO{sub 2} may ameliorate the effects of UV-B radiation, In the present work, the effects of increased atmospheric CO{sub 2} concentration and UV-B radiation on growth and the accumulation of different types of secondary metabolites were studied in silver birch (Betula pendula Roth). Seedlings were exposed to 350 and 700 {mu} mol mol{sup -1} of CO{sub 2} in a greenhouse. At both CO{sub 2} levels, additional UV-B was either present (8.16 kJ m{sup -2} day{sup -1} of biologically effective UV-B irradiance) or absent. The time course of accumulation of individual secondary compounds and the shifts in allocation of carbon between biomass and the secondary metabolites (phenolic acids, flavonoids, condensed tannins) were studied during a 1-month-long exposure. Additionally, the activities of enzymes (L-phenylalanine ammonia-lyase [PAL], EC 4.3.1.5; peroxidase, EC 1.11.1.7; polyphenol oxidase, EC 1.10.3.1) were determined for leaves. UV-B radiation significantly increased biomass, PAL activity, and the accumulation of phenolic acids and flavonoids in seedlings. Elevated CO{sub 2} concentration increased the activities of all the enzymes studied and the accumulation of condensed tannins in leaves, especially with UV-B radiation. Because the observed UV-B induction of flavonoids was smaller under a high CO{sub 2} concentration, it was suggested that the excess of carbon in the atmosphere may moderate the effect of UV-B by increasing the metabolic activity of leaves (high enzyme activities) and by changing the allocation of internal carbon between different primary and secondary metabolites in the

  8. Cold Temperature Delays Wound Healing in Postharvest Sugarbeet Roots.

    Science.gov (United States)

    Fugate, Karen K; Ribeiro, Wellington S; Lulai, Edward C; Deckard, Edward L; Finger, Fernando L

    2016-01-01

    Storage temperature affects the rate and extent of wound-healing in a number of root and tuber crops. The effect of storage temperature on wound-healing in sugarbeet (Beta vulgaris L.) roots, however, is largely unknown. Wound-healing of sugarbeet roots was investigated using surface-abraded roots stored at 6 and 12°C for 28 days. Surface abrasions are common injuries of stored roots, and the storage temperatures used are typical of freshly harvested or rapidly cooled roots. Transpiration rate from the wounded surface and root weight loss were used to quantify wound healing. At 12°C, transpiration rate from the wounded surface declined within 14 days and wounded roots lost weight at a rate similar to unwounded controls. At 6°C, transpiration rate from the wounded surface did not decline in the 28 days after injury, and wounded roots lost 44% more weight than controls after 28 days storage. Melanin formation, lignification, and suberization occurred more rapidly at 12°C than at 6°C, and a continuous layer of lignified and suberized cells developed at 12°C, but not at 6°C. Examination of enzyme activities involved in melanin, lignin, and suberin formation indicated that differences in melanin formation at 6 and 12°C were related to differences in polyphenol oxidase activity, although no relationships between suberin or lignin formation and phenylalanine ammonia lyase or peroxidase activity were evident. Wound-induced respiration was initially greater at 12°C than at 6°C. However, with continued storage, respiration rate of wounded roots declined more rapidly at 12°C, and over 28 days, the increase in respiration due to injury was 52% greater in roots stored at 6°C than in roots stored at 12°C. The data indicate that storage at 6°C severely slowed and impaired wound-healing of surface-abraded sugarbeet roots relative to roots stored at 12°C and suggest that postharvest losses may be accelerated if freshly harvested roots are cooled too quickly. PMID

  9. Hydrogen peroxide is involved in the signal transduction of salicylic acid-induced salvianolic acid B biosynthesis in Salvia miltiorrhiza cell cultures%H2O2参与水杨酸诱导丹参培养细胞中丹酚酸B合成的信号转导

    Institute of Scientific and Technical Information of China (English)

    陈红艳; 刘连成; 董娟娥; 夏广东

    2012-01-01

    Hydrogen peroxide (H2O2), one of reactive oxygen species, is widely generated in many biological systems, and it mediates various physiological and biochemical process in plants. To investigate the role of H2O2 as a signaling molecule in the process of salicylic acid (SA)-induced Salvianolic acid B (Sal B) accumulation, we separately inspected the cultured cells of Salvia miltiorrhiza with SA, H2O2, Catalase (CAT), 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide (DMTU) and Imidazole (IMD) to investigate the influence on the activity of phenylalanine ammonia-lyase (PAL) and tyrosine aminotransferase (TAT) and the accumulation of Sal B. Treatment of S. miltiorrhiza cells with SA resulted in an increase of H2O2, the increase of PAL and TAT and accumulation of Sal B. Exogenous application of 10-30 mmol/L H2O2 was found to effectively increase PAL and TAT activity as well as the Sal B content. CAT, a H2O2 scavenger, eliminated the Sal B-accumulating effects of exogenous H2O2 and SA. These indicated that H2O2 may serve as an upstream signaling molecule in the SA-induced accumulation of Sal B signal transduction pathway. Disposed by DMTU, a chemical trap for H2O2, as observed to be effective in inhibiting SA-induced accumulation of Sal B. IMD strongly inhibits the activity of NADPH oxidase, which is one of the main sources of H2O2 formation in plant cells. IMD treatment strongly inhibited the accumulation of Sal B in cultured cells of S. miltiorrhiza, but the effects of IMD, can be partially reversed by the exogenous SA. The accumulation of Sal B was blocked once the generation of H2O2 by NADPH oxidase was inhibited, and H2O2 served as signaling molecule mediated the SA-induced Sal B accumulation.%过氧化氢(Hydrogen peroxide,H2O2)为活性氧(Reactive oxygen species,ROS)的一种,存在于许多生物体系中并介导植物中多种生理和生化过程.为了探讨H2O2作为信号分子在水杨酸(Salicylic acid,SA)诱导丹参培

  10. Defense Response and Physiological Difference of Rice Cultivars with Different Sheath Blight Resistance Levels to the Toxins Produced by Rhizoctonia solani%不同抗性水平水稻品种对纹枯病菌毒素的防卫反应与生理差异

    Institute of Scientific and Technical Information of China (English)

    左示敏; 潘学彪; 陈夕军; 陈红旗; 徐艳; 张家豪; 陈羽; 陈宗祥; 童蕴慧; 徐敬友

    2014-01-01

    毒素是水稻纹枯病菌(立枯丝核菌 Rhizoctonia solani AG1-IA)的重要致病因子。研究水稻对毒素的抗性反应、耐受性与对纹枯病菌的抗性间的关系,可为利用毒素快速筛选、鉴定水稻品种的抗病性提供参考依据。研究显示,经乙醚萃取、硅胶柱层析获得的纹枯病菌毒素可显著抑制水稻胚根伸长、诱导典型的纹枯病水渍斑,具有明显生物学活性;以一定浓度的毒素处理水稻植株,可诱导寄主体内过氧化物酶、多酚氧化酶、苯丙氨酸解氨酶和超氧化物歧化酶等防御酶活性升高,且速度或程度与品种抗性水平有关,抗病品种的酶活明显高于感病品种。水稻品种对纹枯病的抗性越强,毒素对其胚根伸长抑制率、细胞膜损伤率和磷素外渗率就越低。毒素活性在长时间光照、高温、强酸、强碱和强氧化性化合物如高锰酸钾中明显下降。%Toxins produced by rice sheath blight (SB ) pathogen, Rhizoctonia solani AG1-IA, are important pathogenicity or virulence factors.It is important to investigate the rice response to the toxin and the correlation between the rice cultivar’s sensitivity to the toxin and susceptibility to the pathogen,which can provide an alternative way for quick selection and identification of resistant cultivars to SB by using SB-toxin.The SB-toxin,extracted by ether and silica gel column chromatography,were biologically active and could inhibit radicle growth of rice seeds and induce typical water-soaked SB-like symptom.After the treatment of SB-toxin at appropriate concentrations,the activities of rice defense enzymes,peroxidase,polyphenol oxidase,phenylalanine ammonia lyase,and superoxide dismutase,were quickly induced with faster rates in SB resistant cultivars than those in susceptible cultivars.The cultivars with higher SB resistance generally presented lower inhibition ratio of radicle growth and fewer ratios of damaged membrane and

  11. Indução de resistência à podridão-parda em pêssegos pelo uso de eliciadores em pós-colheita Induction of resistance to brown-rot on peaches by elicitors use in post-harvest

    Directory of Open Access Journals (Sweden)

    Moeses Andrigo Danner

    2008-07-01

    aqueous solution containing the treatments and, after 12 hours, the inoculation of Monilinia fructicola was carried out (0.2 mL of spore suspension with 10(5 spores mL-1, in each side of the fruit. Sixty hours past inoculation, the size of lesions, esporulation and percentage of control were evaluated. The contents of total protein, total phenol, total and reducing sugar, besides activity of phenylalanine ammonia-lyase (PAL, were determined. The elicitors induce resistance to M. fructicola, with reduction in fungal development. Elicitor's increased the evaluated biochemical parameters and the activity of PAL, which was related to the size reduction of lesions in peaches. The elicitors could be used in integrated management of brown-rot, in post-harvest applications.

  12. Aumento do potencial de armazenamento refrigerado de nêsperas 'Fukuhara' com o uso de tratamento térmico Potential increasing in the cold-storage of 'Fukuhara' loquat using heat treatments

    Directory of Open Access Journals (Sweden)

    Fernando Kazuhiro Edagi

    2009-10-01

    C for 7 days, and at 1ºC for 53 days; storage at 10ºC for 7 days, and at 1ºC for 53 days; intermittent heat, in cycles of 6 days at 1ºC + 1 day at 15ºC, for 60 days; fruit conditioning at 37ºC for 3 hours, and at 1ºC for 60 days; and fruit conditioning at 37ºC for 6 hours, and at 1ºC for 60 days. The fruits were kept at 85-90% relative humidity, over the whole storage. The following parameters were determined: pulp firmness, incidence of internal browning, titrable acidity, pH, content of soluble solids, ascorbic acid and phenolic compounds, activity of phenylalanine ammonia-lyase (PAL, polyphenol oxidase (PPO and peroxidase (POD, in evaluations after 15, 30, 45 and 60 days of storage. There was a correlation between firmness level and POD activity, after 60 days of cold storage. Intermittent heat and at 37ºC for 3 hours were efficient in controling internal browning in fruit pulp. Heat treatments did not prevent the increase of pulp firmness. Heat treatments increase cold-storage potential of loquat without changing fruit physicochemical properties.

  13. Activation of Reactive Oxygen Species and Defense Responses in Tobacco Cells Treated with Riboflavin%核黄素对烟草悬浮细胞活性氧和防卫反应的激活作用

    Institute of Scientific and Technical Information of China (English)

    刘菲; 魏芳芳; 王蕾; 刘辉; 梁元存; 刘爱新

    2009-01-01

    基质碱性化、增强4种防卫基因PR(pathogenesis-related)-1a、PR-1b、PAL(phenylalanine ammonia lyase)和LPO(lignin peroxidase)表达以及scopoletin的积累;LaCl_3、EGTA和staurosporine可以不同程度地抑制这些防卫反应.[结论]核黄素能够激活烟草悬浮细胞的氧进发和防卫反应,在信号转导中钙信号和蛋白质磷酸化参与了这些过程.

  14. Trends in lignin modification: a comprehensive analysis of the effects of genetic manipulations/mutations on lignification and vascular integrity

    Science.gov (United States)

    Anterola, Aldwin M.; Lewis, Norman G.

    2002-01-01

    A comprehensive assessment of lignin configuration in transgenic and mutant plants is long overdue. This review thus undertook the systematic analysis of trends manifested through genetic and mutational manipulations of the various steps associated with monolignol biosynthesis; this included consideration of the downstream effects on organized lignin assembly in the various cell types, on vascular function/integrity, and on plant growth and development. As previously noted for dirigent protein (homologs), distinct and sophisticated monolignol forming metabolic networks were operative in various cell types, tissues and organs, and form the cell-specific guaiacyl (G) and guaiacyl-syringyl (G-S) enriched lignin biopolymers, respectively. Regardless of cell type undergoing lignification, carbon allocation to the different monolignol pools is apparently determined by a combination of phenylalanine availability and cinnamate-4-hydroxylase/"p-coumarate-3-hydroxylase" (C4H/C3H) activities, as revealed by transcriptional and metabolic profiling. Downregulation of either phenylalanine ammonia lyase or cinnamate-4-hydroxylase thus predictably results in reduced lignin levels and impaired vascular integrity, as well as affecting related (phenylpropanoid-dependent) metabolism. Depletion of C3H activity also results in reduced lignin deposition, albeit with the latter being derived only from hydroxyphenyl (H) units, due to both the guaiacyl (G) and syringyl (S) pathways being blocked. Apparently the cells affected are unable to compensate for reduced G/S levels by increasing the amounts of H-components. The downstream metabolic networks for G-lignin enriched formation in both angiosperms and gymnosperms utilize specific cinnamoyl CoA O-methyltransferase (CCOMT), 4-coumarate:CoA ligase (4CL), cinnamoyl CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD) isoforms: however, these steps neither affect carbon allocation nor H/G designations, this being determined by C4H/C3H

  15. Efeito da quitosana na emergência, desenvolvimento inicial e caracterização bioquímica de plântulas de Acacia mearnsii Effect of chitosan in emergency, initial development and biochemical characterization of acacia mearnsii seedlings

    Directory of Open Access Journals (Sweden)

    Álvaro Rodrigo Freddo

    2012-12-01

    Silviculture Unepe and in the Plant Health Laboratory at the Federal Technological University of Paraná - Campus Dois Vizinhos. Acacia mearnsii seeds were treated with different concentrations of chitosan (0; 0.25; 0.5; 1 and 2% and grown in tubes with substrate contaminated with Rhizoctonia solani. Twenty two days after sowing, the emergence percentage, the index of germination speed, the seedling height, the radicule length, the fresh weight, and biochemical variables of leaf tissues, the protein content and total phenolic compounds and the activity of the enzyme phenylalanine ammonia-lyase (PAL were evaluated. The results showed that concentrations of chitosan between 0.6 and 0.9 % were more effective in promoting germination and seedling development. Biochemically, chitosan demonstrated ability to change the protein content and activity of PAL, an enzyme which is the branching point between primary and secondary metabolism, indicating the possibility of activation of the plant defense system by seed treatment with chitosan.

  16. Gene regulation of anthocyanin biosynthesis in two blood-flesh peach (Prunus persica (L.) Batsch) cultivars during fruit development%两个红肉桃品种果实发育期花色素苷合成与分子调控研究

    Institute of Scientific and Technical Information of China (English)

    Yun JIAO; Rui-juan MA; Zhi-jun SHEN; Juan YAN; Ming-liang YU

    2014-01-01

    The blood-flesh peach has become popular in China due to its attractive anthocyanin-induced pigmenta-tion and antioxidant properties. In this study, we investigated the molecular mechanisms underlying anthocyanin accumulation by examining the expression of nine genes of the anthocyanin biosynthesis pathway found in the peach mesocarp. Expression was measured at six developmental stages in fruit of two blood-flesh and one white-flesh peach cultivars, using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results show that the ex-pression of the chalcone synthase (CHS) gene was closely related to anthocyanin accumulation in both of the blood-flesh peaches. In the white-flesh peach, we found that the transcription level of phenylalanine ammonia-lyase (PAL) during fruit development was much lower than that in the blood-flesh peach, even though all other genes of the anthocyanin biosynthesis pathway were highly expressed, suggesting that thePAL gene may be limiting in antho-cyanin production in the white-flesh peach. Moreover, the transcription levels of theCHS and UDP-glucose-flavonoid 3-O-glucosyltransferase (UFGT) genes were markedly up-regulated at three days after bag removal (DABR) in the blood-flesh peach, suggesting thatCHS andUFGT are the key genes in the process of anthocyanin biosynthesis for both of the blood-flesh peaches. The present study wil be of great help in improving understanding of the molecular mechanisms involved in anthocyanin accumulation in blood-flesh peaches.%研究目的:深入分析两个红肉桃品种果实发育期花色素苷合成差异的分子机理,为红肉桃品种的遗传改良与利用提供理论依据。  创新要点:阐明两个红肉桃品种果实发育期花色素苷生物的合成与相关基因的时空表达规律,探讨造成两个品种花色素苷积累差异的内在分子机制。  研究方法:应用高效液相色谱(HPLC)和逆转录聚合酶链式反应(RT-PCR

  17. Enhanced Synthesis of Curculigoside by Stress and Amino Acids in Static Culture of Curculigo orchioides Gaertn (Kali Musli)

    Science.gov (United States)

    Chaturvedi, Pratibha; Briganza, Vincent

    2016-01-01

    medicinal plant used for many medicinal purposes such as impotency, aphrodisiac, tonic, jaundice, and skin ailments.It was observed that dry matter % was maximum in 6-week-old tissue fed with 2.5 mg/100 ml of tyrosine and diminished beyond this concentration among all samples usedThe nickel (Ni) and chromium (Cr) stress has enhanced the curculigoside in considerable amount in nontoxic range, in tissue culture of C. orchioides.Curculigoside content was maximum in 6-week-old tissue induced with 3 ppm of Cr (7.63%; 11-fold enhancement) followed by 4 weeks tissue of tissue fed with 4 ppm of Ni (5.66%) and 4-week-old tissue fed with tyrosine 7.5 mg/100 ml (2.38%) among all samples used. Histological studies confirmed the enhanced production of curculigoside. Abbreviations Used: Phe: Phenylalanine, PAL: Phenylalanine ammonia-lyase, mM: mille Molar, Cr: Chromium, Ni: Nickel, HPTLC: High-performance thin layer chromatography PMID:27365988

  18. Indução de resistência em tomateiro por extratos aquosos de Lentinula edodes e Agaricus blazei contra Ralstonia solanacearum Induction of resistance in tomato plants by aqueous extracts of Lentinula edodes and Agaricus blazei against Ralstonia solanacearum

    Directory of Open Access Journals (Sweden)

    Ricardo F. Silva

    2007-06-01

    the extracts and with ASM two days before inoculation in greenhouse conditions. The evaluations were based upon disease severity and activity of some enzymes. In general, the isolates of A. blazei and L. edodes, as well as ASM, did not inhibit in vitro bacterial growth. In treated plants, the isolate Le-96/17 10 % (v/v of L. edodes and ASM significantly reduced bacterial wilt. Chitinase, phenylalanine ammonia-lyase and polyphenoloxidase activities were not changed for most of the treatments; however, increased chitinase activity was verified in plants treated with ASM. The ASM, Abl-26 and Le-96/17 treatments increased peroxidase activity in plants and, based upon the results, L. edodes mushroom and ASM both exhibit potential to reduce bacterial wilt in tomato plants, probably by inducing resistance.

  19. Acibenzolar-S-Metil e Ecolife® na indução de respostas de defesa do tomateiro contra a mancha bacteriana (Xanthomonas vesicatoria Acibenzolar-S-methyl and Ecolife® in the induction of defense responses in tomato against bacterial spot (Xanthomonas vesicatoria

    Directory of Open Access Journals (Sweden)

    Fábio Rossi Cavalcanti

    2006-08-01

    of Ecolife® and ASM caused disease reduction of 39.2% and 47.7%, respectively. The expression of resistance induced by ASM and Ecolife® was evidenced by the increase at peroxidase (POX and polyphenol oxidase (PPO activities, starting in the first hours after spraying. Despite the slight decrease in phenylalanine ammonia-lyase (PAL activity three days after spraying, plants treated with ASM or Ecolife® and inoculated with X. vesicatoria showed a slight increase in lignin deposits. The content of total soluble phenolic compounds decreased significantly at 9 and 12 days after spraying. Increased POX and PPO activities might result in lignification, which may be associated with the tomato's defense strategy against bacterial leaf spot.

  20. Efeito de produtos químicos sobre a mancha bacteriana (Xanthomonas perforans e na ativação de proteínas relacionadas à patogênese em tomateiro Effect of chemicals on the bacterial spot (Xanthomonas perforans and the activation of pathogenesis-related proteins in tomato

    Directory of Open Access Journals (Sweden)

    Adriana Terumi Itako

    2012-08-01

    treatment, all plants were inoculated with X. perforans (10(6 CFU / mL. Leaf discs were collected for assessment of peroxidase, polyphenol oxidase, β-1,3 glucanase, phenylalanine ammonia lyase and protease. The area under the disease progress curve (AUDPC was calculated with the data of severity. All treatments had reduced AUDPC compared to the inoculated control. Fungicides acibenzolar-S-methyl, pyraclostrobin, and pyraclostrobin + methiran had more satisfactory results in reducing the severity of bacterial spot on tomato. The products based on pyraclostrobin together with acibenzolar-S-methyl induced enzymatic activities of peroxidase, polyphenoloxidase and β-1,3 glucanase, indicating that these products may be related to the induction of resistance to bacterial spot on tomato plants.

  1. 光质对姜黄生理特性及根茎次生代谢的影响%Effects of Light Qualities on Physiological Characteristics and Accumulation of Secondary Metabolites in Rhizomes of Curcuma longa L

    Institute of Scientific and Technical Information of China (English)

    刘建福; 王明元; 唐源江; 范燕萍; 钟书淳; 陈钦

    2014-01-01

    The effects of different light qualities generated by light emitting diodes (LED) on the key enzymatic activity of secondary metabolic pathways, the content of organic acid and curcuminoids of Curcuma longa were studied. The results showed that red ligh increased curcumin content in Curcuma longa. The blue light en-hanced the contents of protein and activated the activities of phenylalanin ammonia-lyase (PAL), cinnamic ac-id-4-hydroxylase (C4H) and 4-coumaric acid:CoA ligase (4CL), promoted the accumulation of cinnamic acid, p-coumaric acid, coffee acid and ferulic acid, and then improved the content of curcumin and demethoxycur-cumin, bisdemethoxycurcumin. While green light inhibited the activity of related enzyme, reduced the content of metabolic intermediates and curcuminoids. Combined light with red and blue advanced the activity of PAL, C4H and 4CL, promoted the accumulation of cinnamic acid, p-coumaric acid, coffee acid and ferulic acid, and advanced the content of curcumin and demethoxycurcumin, bisdemethoxycurcumin. Red light ratio for 50%–70%raised the contents of chlorophyll, carotenoid, soluble sugar and protein in Curcuma longa. It was obvious that red light ratio for 70%signiifcantly enhanced the content of curcuminoids. The contents of curcumin and demethoxycurcumin, bisdemethoxycurcumin signiifcantly increased 77.39%, 44.32%and 43.80%, respectively. It suggested that red light ratio for 70%was the optimum for secondary metabolite accumulation in Curcuma longa, while green light and far red light were not conducive to the accumulation of secondary metabolites in Curcuma longa.%以发光二级管(LED)为光源研究不同光质对姜黄生理、姜黄素生物合成关键酶活性、有机酸和姜黄素类化合物含量的影响。试验结果表明:红光有利于提高姜黄素含量;蓝光提高姜黄叶片蛋白质,激活苯丙氨酸解氨酶(PAL)、肉桂酸-4-羟化酶(C4H)和4-香豆酸:辅酶A连接酶(4CL)活性,促进肉桂酸

  2. Botrytis cinerea Activator Protein Induce Resistance-Related Enzyme Activities and Enhancement of Disease Resistance in Tomato Plants%灰霉菌激活蛋白诱导抗病相关的酶活性提高番茄抗病性

    Institute of Scientific and Technical Information of China (English)

    麦麦提艾力·热合曼; 海利力·库尔班; 郭立华; 邱德文

    2014-01-01

    The Botrytis cinerea hypha has been sonication with HEPES buffer (pH 8.0), and the crude protein solution was heated at 100 ℃ for 30 min, the protein solution filtrate was loaded on RESOURCETMQ 5 mL column at flow rate of 2 mL/min. Two peaks were collected, and the both peaks were analyzed by SDS-PAGE, and then the target protein (Botrytis cinerea activator protein) was detected hypersensitive response (HR) on tobacco leaves. Tomato seeds were subjected for a period of 45 days to 2.5, 5, 10 and 20μg/mL of Botrytis cinerea activator protein (the molecular weight is16 kD) solution treatments, and 20 mmol/L HEPES buffer (pH 8.0) was used as control. Then inoculated by spray of 105 cfu/mL the gray mold spore suspension and moisture 48 hours in incubator, and observed the morbidity at the 7, 14 and 21th days of inoculation;And sprayed 10μg/mL protein solutions on tomato seedlings, then measured the phenylalanine ammonia-lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO) activities at 6, 12, 24, 48, 72 and 120 hours of treatment. The results showed that, the linear elution peak showing a single band with Coomassie Brilliant Blue R-250 staining, and this protein could induce the HR in plants. The disease resistance increased by 48%, 55% and 54% in seed treatment tomato respectively, and it showed most resistant at 10μg/mL of the protein concentration. The PAL activity reached the peak value after 24 h of treatment, and it increased by 54%than that of the control. The activities of POD and PPO reached the peak value at 72 h of spray activator protein on tomato seedlings, and it increased by 106%and 122%than that of the control, respectively. Conclusion that, the activator protein involves the improvement disease-resistance by enhancement of the resistance-related enzyme activities in tomato, and the resistant effect was most efficient at the optimal concentration of the protein.%灰霉菌中提取纯化16 kD的激活蛋白。番茄种子以20 mmol

  3. Two Dioryctria Species with Different Survival Strategies to Adapt to Chemical Defense of Host Plant Pinus koraiensis%红松的化学防御及冷杉梢斑螟和赤松梢斑螟的生存策略

    Institute of Scientific and Technical Information of China (English)

    王琪; 严善春; 徐波

    2012-01-01

    Dioryctria abietella and D. sylvestrella are close relative species in the same genus, and both endanger cones of Pinus koraiensis concomitantly, but their biological and ecological behaviors are quite different. To investigate the interactions between the host P. koraiensis chemical defense and physiological adaptation of the two D. species, we analyzed the larvae midgut detoxication enzymes and protective enzymes activities in lth, 3rd, Sth instars, and the defense enzymes in healthy, fed pine cones or top shoots at the corresponding period. The results showed that phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) activities in healthy cones and shoots were changed with the development stage. The two D. larvae feeding induced those defense enzymes activities significantly increased compared with healthy cones or tips. Detoxication enzymes and protective enzymes in the two D. species, which have different survival strategies, were quite different. D. abietella specifically fed on cone through larval stage, and their detoxication enzymes, S-transferase (GST), carboxylesterase (CarE), multi-function oxidase (MFO) in midgut were significantly higher than D. sylvestrella larvae that alternatively fed on cones and tips. There were no significant differences in superoxide dismutase (SOD) and chitinase (CT) activities in D. abietella and D. sylvestrella midgus, and the two protective enzymes activities were not related to whether transferred feeding. Phenoloxidase (PO) and peroxidase (POD) in D. sylvestrella midguts had higher activity compared with D. abietella, suggesting that the higher activity could facilitate them to avoid the threat of the transfer process. The results indicated that the physiological detoxification was the predominant survival strategies for D. abietella larvae to adapt to chemical defense of host plant, whereas D. sylvestrella larvae survived not only by carrying out the

  4. Trends in lignin modification: a comprehensive analysis of the effects of genetic manipulations/mutations on lignification and vascular integrity

    Science.gov (United States)

    Anterola, Aldwin M.; Lewis, Norman G.

    2002-01-01

    A comprehensive assessment of lignin configuration in transgenic and mutant plants is long overdue. This review thus undertook the systematic analysis of trends manifested through genetic and mutational manipulations of the various steps associated with monolignol biosynthesis; this included consideration of the downstream effects on organized lignin assembly in the various cell types, on vascular function/integrity, and on plant growth and development. As previously noted for dirigent protein (homologs), distinct and sophisticated monolignol forming metabolic networks were operative in various cell types, tissues and organs, and form the cell-specific guaiacyl (G) and guaiacyl-syringyl (G-S) enriched lignin biopolymers, respectively. Regardless of cell type undergoing lignification, carbon allocation to the different monolignol pools is apparently determined by a combination of phenylalanine availability and cinnamate-4-hydroxylase/"p-coumarate-3-hydroxylase" (C4H/C3H) activities, as revealed by transcriptional and metabolic profiling. Downregulation of either phenylalanine ammonia lyase or cinnamate-4-hydroxylase thus predictably results in reduced lignin levels and impaired vascular integrity, as well as affecting related (phenylpropanoid-dependent) metabolism. Depletion of C3H activity also results in reduced lignin deposition, albeit with the latter being derived only from hydroxyphenyl (H) units, due to both the guaiacyl (G) and syringyl (S) pathways being blocked. Apparently the cells affected are unable to compensate for reduced G/S levels by increasing the amounts of H-components. The downstream metabolic networks for G-lignin enriched formation in both angiosperms and gymnosperms utilize specific cinnamoyl CoA O-methyltransferase (CCOMT), 4-coumarate:CoA ligase (4CL), cinnamoyl CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD) isoforms: however, these steps neither affect carbon allocation nor H/G designations, this being determined by C4H/C3H

  5. Effects of different light intensities on activities of the primary defense proteins in needles of Larix gmelinii%不同光照强度对兴安落叶松几种主要防御蛋白活力的影响

    Institute of Scientific and Technical Information of China (English)

    鲁艺芳; 石蕾; 严善春

    2012-01-01

    role in protection from insect herbivory. Chemical defenses include secondary metabolites and proteins. The primary defense proteins consist of protective enzymes, e. g. peroxidase (POD) , superoxide dismutase (SOD) and catalase (CAT) ; defense enzymes, e. g. polyphenol oxidase (PPO) and phenylalanine ammonia-lyase ( PAL) ; protease inhibitors, e. g. trypsin inhibitor ( TI) and chymotrypsin inhibitor ( CI). In many organisms, light is a crucial environmental signal influencing natural physiological and developmental processes. There are different effects on the phenotypic and physiological characteristics even if the same plant species with the long-term growth in different light condition. In order to understand the impact of sunlight on the constitutive defenses of Larix gmelinii, sunlight control treatments with three intensities; 100% of natural sunlight (NS), about 50% and 25% of natural sunlight ( NS/2, NS/4) were conducted to simulate the light conditions of forest edge, forest gap and understory where the Larix gmelinii grows. Sunlight control was achieved by erecting shade shelters of woven black nylon netting. The activities of the primary defense proteins in the needles of Larix gmelinii seedlings under different light treatments were measured. The activities of POD, SOD, PAL, PPO and CI under 50% and 25% of natural sunlight conditions were significantly (P< 0.05) higher than those under 100% of natural sunlight conditions both in June, July and August. The activities of POD and CI were greatest under 50% of natural sunlight conditions while the activities of SOD, PAL and PPO were greatest under 25% of natural sunlight conditions. But the CAT activities were significantly (P<0.05) decreased under the shade conditions. The activities of TI were significantly (f<0.05) changed under different light treatments, but the variation was not regular. The activities of the primary defense proteins showed significant (P<0.05) differences under the same light intensity

  6. 拟松材线虫携带细菌对云南松的致病性%Pathogenicity of bacterium carried by Bursaphelenchus mucronatus on Pinus yunnanensis

    Institute of Scientific and Technical Information of China (English)

    李姝江; 朱天辉; 张兴华

    2014-01-01

    Summary Pine wood nematode (PWN) is a destructive disease to pines.For the research on its pathogenic mechanism,the theory which is about the complex infection of PWN and the bacterium carried by it is recognized. Bursaphelenchus mucronatus is considered as a related species of Bursaphelenchus xylophilus ,which may be differentiation with the homologous species in different environments.In early studies,B.mucronatus was served as contrast species to B.xylophilus due to the weak or lacking pathogenicity.But recently,many reports have pointed out that it has the strong pathogenicity and can cause the widespread death of pines,which referred to Pinus thunbergii P.yunnanensis P.taiwanensis P.densata ,etc.The large numbers of P.yunnanensis were dead in Sichuan in recent years. However,no systematic study was conducted on the pathogenicity of the bacterium carried by B.mucronatus .This study has the aim of evaluating the effects of the bacterium carried by B.mucronatus on wilting ratio and phenylpropanoid metabolism of pine needles,and further exploring the effect of bacterium in the pathogenic process of B.mucronatus . Two-year-old P.yunnanensis seedlings,B.mucronatus isolated from PWN disease district in Sichuan,the bacterium carried by B.mucronatus and its metabolite as the materials,the wilting ratio was calculated,and the total phenol content, phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD) activities were determined by the inoculation of burette to branch phloem of P.yunnanensis in laboratory,which represented the pathogenicity of the bacterium and its metabolite on P.yunnanensis . The results showed that Pectobacterium cypripedii and its non-protein metabolite had strongest effect on P. yunnanensis in 26 species of bacteria isolated from the surface of nematodes,and the wilting degree and wilting ratio were significantly high in these two treatments.They caused the accumulation of total phenol content and the changes of PAL,PPO and