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Sample records for ammonia-lyases

  1. Phenylalanine ammonia-lyase (PAL) gene activity in response to ...

    African Journals Online (AJOL)

    Phenylalanine ammonia-lyase (PAL) catalyzes the biosynthesis of rosmarinic acid (RA), tyrosine and phenylalanine are the precursors of RA, while proline drives metabolite precursors toward Shikimate and phenylpropanoid pathway ending with the production of RA. The aim of this study was to investigate the PAL gene ...

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

    NARCIS (Netherlands)

    Heberling, Matthew M.; Wu, Bian; Bartsch, Sebastian; Janssen, Dick B.

    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

  3. Circadian Rhythmicity in the Activities of Phenylalanine Ammonia-Lyase from Lemna perpusilla and Spirodela polyrhiza 1

    Science.gov (United States)

    Gordon, William R.; Koukkari, Willard L.

    1978-01-01

    The oscillations in phenylalanine ammonia-lyase activity from Spirodela polyrhiza and phenylalanine ammonia-lyase and tyrosine ammonia-lyase activities from Lemna perpusilla displayed a circadian rhythm under continuous light. Rhythmicity in enzymic activity could not be detected in continuous darkness since under this condition phenylalanine ammonia-lyase activity remains at a fairly constantly low level. Results from our studies of the oscillatory pattern of the respective activities of phenylalanine and tyrosine ammonia-lyase support their “inseparability.” PMID:16660569

  4. 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.

  5. 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.

  6. Processes for the production of hydroxycinnamic acids using polypeptides having tyrosine ammonia lyase activity

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention generally relates to the field of biotechnology as it applies to the production of hydroxycinnamic acids using polypeptides having tyrosine ammonia lyase activity. More particularly, the present invention pertains to polypeptides having tyrosine ammonia lyase activity and high...... substrate specificity towards tyrosine, which makes them particularly suitable in the production of p-coumaric acid and other hydroxycinnamic acids. The present invention thus provides processes for the production of p-coumaric acid and other hydroxycinnamic acids employing these polypeptides as well...

  7. 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.

  8. Catalytic Mechanisms and Biocatalytic Applications of Aspartate and Methylaspartate Ammonia Lyases

    NARCIS (Netherlands)

    de Villiers, Marianne; Veetil, Vinod Puthan; Raj, Hans; de Villiers, Jandre; Poelarends, Gerrit J.

    2012-01-01

    Ammonia lyases catalyze the formation of alpha-beta-unsaturated bonds by the elimination of ammonia from their substrates. This conceptually straightforward reaction has been the emphasis of many studies, with the main focus on the catalytic mechanism of these enzymes and/or the use of these enzymes

  9. 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

  10. Engineering methylaspartate ammonia lyase for the asymmetric synthesis of unnatural amino acids

    NARCIS (Netherlands)

    Raj, Hans; Szymanski, Wiktor; de Villiers, Jandre; Rozeboom, Henriëtte J.; Puthan Veetil, Vinod; Reis, Carlos R.; Villiers, Marianne de; Dekker, Frank J.; Wildeman, Stefaan de; Quax, Wim J.; Thunnissen, Andy-Mark W.H.; Feringa, Ben L.; Janssen, Dick B.; Poelarends, Gerrit J.

    The redesign of enzymes to produce catalysts for a predefined transformation remains a major challenge in protein engineering. Here, we describe the structure-based engineering of methylaspartate ammonia lyase (which in nature catalyses the conversion of 3-methylaspartate to ammonia and

  11. Kinetic Resolution and Stereoselective Synthesis of 3-Substituted Aspartic Acids by Using Engineered Methylaspartate Ammonia Lyases

    NARCIS (Netherlands)

    Raj, Hans; Szymanski, Wiktor; Villiers, Jandré de; Puthan Veetil, Vinod; Quax, Wim J.; Shimamoto, Keiko; Janssen, Dick B.; Feringa, Ben L.; Poelarends, Gerrit J.

    2013-01-01

    Kinetic resolution and asymmetric synthesis of various valuable 3-substituted aspartic acids, which were obtained in fair to good yields with diastereomeric ratio values of up to >98:2 and enantiomeric excess values of up to >99 %, by using engineered methylaspartate ammonia lyases are described.

  12. Crystal structure and characterization of a novel L-serine ammonia-lyase from Rhizomucor miehei

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Zhen [College of Food Science and Nutritional Engineering, Beijing Advanced Innovation Center of Food Nutrition and Human Health, China Agricultural University, Beijing 100083 (China); Yan, Qiaojuan [College of Engineering, China Agricultural University, Beijing 100083 (China); Ma, Qingjun [Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Jiang, Zhengqiang, E-mail: zhqjiang@cau.edu.cn [College of Food Science and Nutritional Engineering, Beijing Advanced Innovation Center of Food Nutrition and Human Health, China Agricultural University, Beijing 100083 (China)

    2015-10-23

    L-serine ammonia-lyase, as a member of the β-family of pyridoxal-5′-phosphate (PLP) dependent enzymes, catalyzes the conversion of L-serine (L-threonine) to pyruvate (α-ketobutyrate) and ammonia. The crystal structure of L-serine ammonia-lyase from Rhizomucor miehei (RmSDH) was solved at 1.76 Å resolution by X-ray diffraction method. The overall structure of RmSDH had the characteristic β-family PLP dependent enzyme fold. It consisted of two distinct domains, both of which show the typical open twisted α/β structure. A PLP cofactor was located in the crevice between the two domains, which was attached to Lys52 by a Schiff-base linkage. Unique residue substitutions (Gly78, Pro79, Ser146, Ser147 and Thr312) were discovered at the catalytic site of RmSDH by comparison of structures of RmSDH and other reported eukaryotic L-serine ammonia-lyases. Optimal pH and temperature of the purified RmSDH were 7.5 and 40 °C, respectively. It was stable in the pH range of 7.0–9.0 and at temperatures below 40 °C. This is the first crystal structure of a fungal L-serine ammonia-lyase. It will be useful to study the catalytic mechanism of β-elimination enzymes and will provide a basis for further enzyme engineering. - Highlights: • The crystal structure of a fungal L-serine ammonia-lyase (RmSDH) was solved. • Five unique residue substitutions are found at the catalytic site of RmSDH. • RmSDH was expressed in Pichia. pastoris and biochemically characterized. • RmSDH has potential application in splitting D/L-serine.

  13. Ammonia lyases and aminomutases as biocatalysts for the synthesis of α-amino and β-amino acids.

    Science.gov (United States)

    Turner, Nicholas J

    2011-04-01

    Ammonia lyases catalyse the reversible addition of ammonia to cinnamic acid (1: R=H) and p-hydroxycinnamic (1: R=OH) to generate L-phenylalanine (2: R=H) and L-tyrosine (2: R=OH) respectively (Figure 1a). Both phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) are widely distributed in plants, fungi and prokaryotes. Recently there has been interest in the use of these enzymes for the synthesis of a broader range of L-arylalanines. Aminomutases catalyse a related reaction, namely the interconversion of α-amino acids to β-amino acids (Figure 1b). In the case of L-phenylalanine, this reaction is catalysed by phenylalanine aminomutase (PAM) and proceeds stereospecifically via the intermediate cinnamic acid to generate β-Phe 3. Ammonia lyases and aminomutases are related in sequence and structure and share the same active site cofactor 4-methylideneimidazole-5-one (MIO). There is currently interest in the possibility of using these biocatalysts to prepare a wide range of enantiomerically pure l-configured α-amino and β-amino acids. Recent reviews have focused on the mechanism of these MIO containing enzymes. The aim of this review is to review recent progress in the application of ammonia lyase and aminomutase enzymes to prepare enantiomerically pure α-amino and β-amino acids. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Kinetic resolution and stereoselective synthesis of 3-substituted aspartic acids by using engineered methylaspartate ammonia lyases.

    Science.gov (United States)

    Raj, Hans; Szymanski, Wiktor; de Villiers, Jandré; Puthan Veetil, Vinod; Quax, Wim J; Shimamoto, Keiko; Janssen, Dick B; Feringa, Ben L; Poelarends, Gerrit J

    2013-08-19

    Enzymatic amino acid synthesis: Kinetic resolution and asymmetric synthesis of various valuable 3-substituted aspartic acids, which were obtained in fair to good yields with diastereomeric ratio values of up to >98:2 and enantiomeric excess values of up to >99 %, by using engineered methylaspartate ammonia lyases are described. These biocatalytic methodologies for the selective preparation of aspartic acid derivatives appear to be attractive alternatives for existing chemical methods. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. 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 approaches...

  16. Expression and properties of the highly alkalophilic phenylalanine ammonia-lyase of thermophilic Rubrobacter xylanophilus.

    Directory of Open Access Journals (Sweden)

    Klaudia Kovács

    Full Text Available The sequence of a phenylalanine ammonia-lyase (PAL; EC: 4.3.1.24 of the thermophilic and radiotolerant bacterium Rubrobacter xylanophilus (RxPAL was identified by screening the genomes of bacteria for members of the phenylalanine ammonia-lyase family. A synthetic gene encoding the RxPAL protein was cloned and overexpressed in Escherichia coli TOP 10 in a soluble form with an N-terminal His6-tag and the recombinant RxPAL protein was purified by Ni-NTA affinity chromatography. The activity assay of RxPAL with l-phenylalanine at various pH values exhibited a local maximum at pH 8.5 and a global maximum at pH 11.5. Circular dichroism (CD studies showed that RxPAL is associated with an extensive α-helical character (far UV CD and two distinctive near-UV CD peaks. These structural characteristics were well preserved up to pH 11.0. The extremely high pH optimum of RxPAL can be rationalized by a three-dimensional homology model indicating possible disulfide bridges, extensive salt-bridge formation and an excess of negative electrostatic potential on the surface. Due to these properties, RxPAL may be a candidate as biocatalyst in synthetic biotransformations leading to unnatural l- or d-amino acids or as therapeutic enzyme in treatment of phenylketonuria or leukemia.

  17. Cooperative functioning between phenylalanine ammonia lyase and isochorishmate synthase activities contributes to salicylic acid biosynthesis in soybean

    Science.gov (United States)

    Salicylic acid (SA), an essential regulator of plant defense, is derived from chorismate via either the phenylalanine ammonia lyase (PAL), or the isochorishmate synthase (ICS) catalyzed steps. The ICS pathway is thought to be the primary contributor of defense-related SA, at least in Arabidopsis. We...

  18. 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

  19. Cloning, expression and characterization of phenylalanine ammonia-lyase from Rhodotorula glutinis.

    Science.gov (United States)

    Zhu, Longbao; Cui, Wenjing; Fang, Yueqin; Liu, Yi; Gao, Xinxing; Zhou, Zhemin

    2013-05-01

    The industrial-scale production of phenylalanine ammonia-lyase (PAL) mainly uses strains of Rhodotorula. However, the PAL gene from Rhodotorula has not been cloned. Here, the full-length gene of PAL from Rhodotorula glutinis was isolated. It was 2,121 bp, encoding a polypeptide with 706 amino acids and a calculated MW of 75.5 kDa. Though R. glutinis is an anamorph of Rhodosporium toruloides, the amino acid sequences of PALs them are not the same (about 74 % identity). PAL was expressed in E. coli and characterized. Its specific activity was 4.2 U mg(-1) and the k cat/K m was 1.9 × 10(4) mM(-1) s(-1), exhibiting the highest catalytic ability among the reported PALs. The genetic and biochemical information reported here should facilitate future application in industry.

  20. Stabilization of Phenylalanine Ammonia Lyase from Rhodotorula glutinis by Encapsulation in Polyethyleneimine-Mediated Biomimetic Silica.

    Science.gov (United States)

    Cui, Jiandong; Liang, Longhao; Han, Cong; Lin Liu, Rong

    2015-06-01

    Phenylalanine ammonia lyase (PAL) from Rhodotorula glutinis was encapsulated within polyethyleneimine-mediated biomimetic silica. The main factors in the preparation of biomimetic silica were optimized by response surface methodology (RSM). Compared to free PAL (about 2 U), the encapsulated PAL retained more than 43 % of their initial activity after 1 h of incubation time at 60 °C, whereas free PAL lost most of activity in the same conditions. It was clearly indicated that the thermal stability of PAL was improved by encapsulation. Moreover, the encapsulated PAL exhibited the excellent stability of the enzyme against denaturants and storage stability, and pH stability was improved by encapsulation. Operational stability of 7 reaction cycles showed that the encapsulated PAL was stable. Nevertheless, the K m value of encapsulated PAL in biomimetic silica was higher than that of the free PAL due to lower total surface area and increased mass transfer resistance.

  1. Synthesis of d‐ and l‐Phenylalanine Derivatives by Phenylalanine Ammonia Lyases: A Multienzymatic Cascade Process†

    Science.gov (United States)

    Parmeggiani, Fabio; Lovelock, Sarah L.; Weise, Nicholas J.; Ahmed, Syed T.

    2015-01-01

    Abstract The synthesis of substituted d‐phenylalanines in high yield and excellent optical purity, starting from inexpensive cinnamic acids, has been achieved with a novel one‐pot approach by coupling phenylalanine ammonia lyase (PAL) amination with a chemoenzymatic deracemization (based on stereoselective oxidation and nonselective reduction). A simple high‐throughput solid‐phase screening method has also been developed to identify PALs with higher rates of formation of non‐natural d‐phenylalanines. The best variants were exploited in the chemoenzymatic cascade, thus increasing the yield and ee value of the d‐configured product. Furthermore, the system was extended to the preparation of those l‐phenylalanines which are obtained with a low ee value using PAL amination. PMID:27478261

  2. Synthesis of d- and l-Phenylalanine Derivatives by Phenylalanine Ammonia Lyases: A Multienzymatic Cascade Process**

    Science.gov (United States)

    Parmeggiani, Fabio; Lovelock, Sarah L; Weise, Nicholas J; Ahmed, Syed T; Turner, Nicholas J

    2015-01-01

    The synthesis of substituted d-phenylalanines in high yield and excellent optical purity, starting from inexpensive cinnamic acids, has been achieved with a novel one-pot approach by coupling phenylalanine ammonia lyase (PAL) amination with a chemoenzymatic deracemization (based on stereoselective oxidation and nonselective reduction). A simple high-throughput solid-phase screening method has also been developed to identify PALs with higher rates of formation of non-natural d-phenylalanines. The best variants were exploited in the chemoenzymatic cascade, thus increasing the yield and ee value of the d-configured product. Furthermore, the system was extended to the preparation of those l-phenylalanines which are obtained with a low ee value using PAL amination. PMID:25728350

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

    Science.gov (United States)

    Jones, Alex R; Rentergent, Julius; Scrutton, Nigel S; Hay, Sam

    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 during single-turnover stopped-flow measurements. These data are interpreted within the context of a kinetic model where the 5′-deoxyadenosyl radical intermediate may be quasi-stable and rearrangement of the substrate radical is essentially irreversible. Global fitting of these data allows estimation of the intrinsic rate constants associated with CoC homolysis and initial H-abstraction steps. In contrast to previous stopped-flow studies, the apparent kinetic isotope effects are found to be relatively small. PMID:25950663

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

    International Nuclear Information System (INIS)

    Pluskota, W.E.; Michalczyk, D.J.; Gorecki, R.J.

    2005-01-01

    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

  5. Synthesis of specifically labelled L-phenylalanines using phenylalanine ammonia lyase activity

    International Nuclear Information System (INIS)

    Haedener, A.; Tamm, Ch.

    1987-01-01

    Specifically labelled L-phenylalanines have been prepared using a variety of classical synthetic methods in combination with phenylalanine ammonia lyase (PAL) enzyme activity of the yeast Rhodosporidium toruloides ATCC 10788 or Rhodotorula glutinis IFO 0559, respectively. Thus, L-[2- 2 H]phenyl-[2- 2 H]alanine was formed from (E) -[2,2'- 2 H 2 ]cinnamic acid and ammonia in 46% yield, whereas L-phenyl-[2- 13 C, 15 N]alanine was obtained from (E)-[2- 13 C]cinnamic acid in 45% overall yield. Generally, labelled cinnamic acids were recovered in pure form from the reaction mixture, with a loss of 6-8%. Likewise, unchanged 15 NH 3 was reisolated as 15 NH 4 Cl after steam distillation with overall losses of less than 4%. Labelled cinnamic acids were prepared by Knoevenagel condensations between appropriately labelled benzaldehydes and malonic acids. [2- 2 H]Benzaldehyde was obtained from 2-bromotoluene by decomposition of the corresponding Grignard reagent with 2 H 2 O and subsequent oxidation. Since simple molecules, most of them commercially available in labelled form or otherwise easily accessible, may serve as starting material, and due to its defined stereochemistry, the reaction catalysed by PAL opens a short and attractive route to specifically labelled L-phenylalanines. (author)

  6. Synthesis of specifically labelled L-phenylalanines using phenylalanine ammonia lyase activity

    Energy Technology Data Exchange (ETDEWEB)

    Haedener, A.; Tamm, Ch.

    1987-11-01

    Specifically labelled L-phenylalanines have been prepared using a variety of classical synthetic methods in combination with phenylalanine ammonia lyase (PAL) enzyme activity of the yeast Rhodosporidium toruloides ATCC 10788 or Rhodotorula glutinis IFO 0559, respectively. Thus, L-(2-/sup 2/H)phenyl-(2-/sup 2/H)alanine was formed from (E) -(2,2'-/sup 2/H/sub 2/)cinnamic acid and ammonia in 46% yield, whereas L-phenyl-(2-/sup 13/C, /sup 15/N)alanine was obtained from (E)-(2-/sup 13/C)cinnamic acid in 45% overall yield. Generally, labelled cinnamic acids were recovered in pure form from the reaction mixture, with a loss of 6-8%. Likewise, unchanged /sup 15/NH/sub 3/ was reisolated as /sup 15/NH/sub 4/Cl after steam distillation with overall losses of less than 4%. Labelled cinnamic acids were prepared by Knoevenagel condensations between appropriately labelled benzaldehydes and malonic acids. (2-/sup 2/H)Benzaldehyde was obtained from 2-bromotoluene by decomposition of the corresponding Grignard reagent with /sup 2/H/sub 2/O and subsequent oxidation. Since simple molecules, most of them commercially available in labelled form or otherwise easily accessible, may serve as starting material, and due to its defined stereochemistry, the reaction catalysed by PAL opens a short and attractive route to specifically labelled L-phenylalanines.

  7. Optimization of oligomeric enzyme activity in ionic liquids using Rhodotorula glutinis yeast phenylalanine ammonia lyase.

    Science.gov (United States)

    Barron, Christiaan C; Sponagle, Brandon J D; Arivalagan, Pugazhendhi; D'Cunha, Godwin B

    2017-01-01

    Phenylalanine ammonia lyase (E.C.4.3.1.24, PAL) activity of Rhodotorula glutinis yeast has been demonstrated in four commonly used ionic liquids. PAL forward reaction was carried out in 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][MeSO 4 ]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]) and 1-butyl-3-methylimidazolium lactate ([BMIM][lactate]). Our experiments have revealed that PAL is catalytically active in ionic liquids and the enzyme activity in ([BMIM][PF 6 ]) is comparable to that obtained in aqueous buffer medium. Different conditions were optimized for maximal PAL forward activity including time of incubation (30.0min) L -phenylalanine substrate concentration (30.0mM), nature of buffer (50.0mM Tris-HCl), pH (9.0), temperature (37°C), and speed of agitation (100 rev min -1 ). Under these optimized conditions, about 83% conversion of substrate to product was obtained for the PAL forward reaction that was determined using UV spectroscopy at 290nm. PAL reverse reaction in ([BMIM][PF 6 ]) was determined spectrophotometrically at 520nm; and about 59% substrate conversion was obtained. This data provides further knowledge in enzyme biocatalysis in non-aqueous media, and may be of importance when studying the function of other oligomeric/multimeric proteins and enzymes in ionic liquids. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Molecular Cloning and Sequence Analysis of a Phenylalanine Ammonia-Lyase Gene from Dendrobium

    Science.gov (United States)

    Cai, Yongping; Lin, Yi

    2013-01-01

    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. PMID:23638048

  9. 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.

  10. Phenylalanine ammonia lyase catalyzed synthesis of amino acids by an MIO-cofactor independent pathway.

    Science.gov (United States)

    Lovelock, Sarah L; Lloyd, Richard C; Turner, Nicholas J

    2014-04-25

    Phenylalanine ammonia lyases (PALs) belong to a family of 4-methylideneimidazole-5-one (MIO) cofactor dependent enzymes which are responsible for the conversion of L-phenylalanine into trans-cinnamic acid in eukaryotic and prokaryotic organisms. Under conditions of high ammonia concentration, this deamination reaction is reversible and hence there is considerable interest in the development of PALs as biocatalysts for the enantioselective synthesis of non-natural amino acids. Herein the discovery of a previously unobserved competing MIO-independent reaction pathway, which proceeds in a non-stereoselective manner and results in the generation of both L- and D-phenylalanine derivatives, is described. The mechanism of the MIO-independent pathway is explored through isotopic-labeling studies and mutagenesis of key active-site residues. The results obtained are consistent with amino acid deamination occurring by a stepwise E1 cB elimination mechanism. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Formulation and PEGylation optimization of the therapeutic PEGylated phenylalanine ammonia lyase for the treatment of phenylketonuria.

    Science.gov (United States)

    Bell, Sean M; Wendt, Dan J; Zhang, Yanhong; Taylor, Timothy W; Long, Shinong; Tsuruda, Laurie; Zhao, Bin; Laipis, Phillip; Fitzpatrick, Paul A

    2017-01-01

    Phenylketonuria (PKU) is a genetic metabolic disease in which the decrease or loss of phenylalanine hydroxylase (PAH) activity results in elevated, neurotoxic levels of phenylalanine (Phe). Due to many obstacles, PAH enzyme replacement therapy is not currently an option. Treatment of PKU with an alternative enzyme, phenylalanine ammonia lyase (PAL), was first proposed in the 1970s. However, issues regarding immunogenicity, enzyme production and mode of delivery needed to be overcome. Through the evaluation of PAL enzymes from multiple species, three potential PAL enzymes from yeast and cyanobacteria were chosen for evaluation of their therapeutic potential. The addition of polyethylene glycol (PEG, MW = 20,000), at a particular ratio to modify the protein surface, attenuated immunogenicity in an animal model of PKU. All three PEGylated PAL candidates showed efficacy in a mouse model of PKU (BTBR Pahenu2) upon subcutaneous injection. However, only PEGylated Anabaena variabilis (Av) PAL-treated mice demonstrated sustained low Phe levels with weekly injection and was the only PAL evaluated that maintained full enzymatic activity upon PEGylation. A PEGylated recombinant double mutant version of AvPAL (Cys503Ser/Cys565Ser), rAvPAL-PEG, was selected for drug development based on its positive pharmacodynamic profile and favorable expression titers. PEGylation was shown to be critical for rAvPAL-PEG efficacy as under PEGylated rAvPAL had a lower pharmacodynamic effect. rAvPAL and rAvPAL-PEG had poor stability at 4°C. L-Phe and trans-cinnamate were identified as activity stabilizing excipients. rAvPAL-PEG is currently in Phase 3 clinical trials to assess efficacy in PKU patients.

  12. Identification of the substrate radical intermediate derived from ethanolamine during catalysis by ethanolamine ammonia-lyase.

    Science.gov (United States)

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

    2008-10-28

    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. Resolved 13C hyperfine splitting in EPR spectra of samples prepared with [1-13C]ethanolamine and the absence of such splitting in spectra of samples prepared with [2-13C]ethanolamine show that the unpaired electron is localized on C1 (the carbinol carbon) of the substrate. The 13C splitting from C1 persists from 10 ms throughout the time course of substrate turnover, and there was no evidence of a detectable amount of a product like radical having unpaired spin on C2. These results correct an earlier assignment for this radical intermediate [Warncke, K., et al. (1999) J. Am. Chem. Soc. 121, 10522-10528]. The EPR signals of the substrate radical intermediate are altered by electron spin coupling to the other paramagnetic species, cob(II)alamin, in the active site. The dipole-dipole and exchange interactions as well as the 1-13C hyperfine splitting tensor were analyzed via spectral simulations. The sign of the isotropic exchange interaction indicates a weak ferromagnetic coupling of the two unpaired electrons. A Co2+-radical distance of 8.7 A was obtained from the magnitude of the dipole-dipole interaction. The orientation of the principal axes of the 13C hyperfine splitting tensor shows that the long axis of the spin-bearing p orbital on C1 of the substrate radical makes an angle of approximately 98 degrees with the unique axis of the d(z2) orbital of Co2+.

  13. 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.

  14. Formulation and PEGylation optimization of the therapeutic PEGylated phenylalanine ammonia lyase for the treatment of phenylketonuria.

    Directory of Open Access Journals (Sweden)

    Sean M Bell

    Full Text Available Phenylketonuria (PKU is a genetic metabolic disease in which the decrease or loss of phenylalanine hydroxylase (PAH activity results in elevated, neurotoxic levels of phenylalanine (Phe. Due to many obstacles, PAH enzyme replacement therapy is not currently an option. Treatment of PKU with an alternative enzyme, phenylalanine ammonia lyase (PAL, was first proposed in the 1970s. However, issues regarding immunogenicity, enzyme production and mode of delivery needed to be overcome. Through the evaluation of PAL enzymes from multiple species, three potential PAL enzymes from yeast and cyanobacteria were chosen for evaluation of their therapeutic potential. The addition of polyethylene glycol (PEG, MW = 20,000, at a particular ratio to modify the protein surface, attenuated immunogenicity in an animal model of PKU. All three PEGylated PAL candidates showed efficacy in a mouse model of PKU (BTBR Pahenu2 upon subcutaneous injection. However, only PEGylated Anabaena variabilis (Av PAL-treated mice demonstrated sustained low Phe levels with weekly injection and was the only PAL evaluated that maintained full enzymatic activity upon PEGylation. A PEGylated recombinant double mutant version of AvPAL (Cys503Ser/Cys565Ser, rAvPAL-PEG, was selected for drug development based on its positive pharmacodynamic profile and favorable expression titers. PEGylation was shown to be critical for rAvPAL-PEG efficacy as under PEGylated rAvPAL had a lower pharmacodynamic effect. rAvPAL and rAvPAL-PEG had poor stability at 4°C. L-Phe and trans-cinnamate were identified as activity stabilizing excipients. rAvPAL-PEG is currently in Phase 3 clinical trials to assess efficacy in PKU patients.

  15. Structural And Biochemical Characterization of the Therapeutic A. Variabilis Phenylalanine Ammonia Lyase

    Energy Technology Data Exchange (ETDEWEB)

    Wang, L.; Gamez, A.; Archer, H.; Abola, E.E.; Sarkissian, C.N.; Fitzpatrick, P.; Wendt, D.; Zhang, Y.; Vellard, M.; Bliesath, J.; Bell, S.; Lemont, J.; Scriver, C.R.; Stevens, R.C.

    2009-05-26

    We have recently observed promising success in a mouse model for treating the metabolic disorder phenylketonuria with phenylalanine ammonia lyase (PAL) from Rhodosporidium toruloides and Anabaena variabilis. Both molecules, however, required further optimization in order to overcome problems with protease susceptibility, thermal stability, and aggregation. Previously, we optimized PAL from R. toruloides, and in this case we reduced aggregation of the A. variabilis PAL by mutating two surface cysteine residues (C503 and C565) to serines. Additionally, we report the structural and biochemical characterization of the A. variabilis PAL C503S/C565S double mutant and carefully compare this molecule with the R. toruloides engineered PAL molecule. Unlike previously published PAL structures, significant electron density is observed for the two active-site loops in the A. variabilis C503S/C565S double mutant, yielding a complete view of the active site. Docking studies and N-hydroxysuccinimide-biotin binding studies support a proposed mechanism in which the amino group of the phenylalanine substrate is attacked directly by the 4-methylidene-imidazole-5-one prosthetic group. We propose a helix-to-loop conformational switch in the helices flanking the inner active-site loop that regulates accessibility of the active site. Differences in loop stability among PAL homologs may explain the observed variation in enzyme efficiency, despite the highly conserved structure of the active site. A. variabilis C503S/C565S PAL is shown to be both more thermally stable and more resistant to proteolytic cleavage than R. toruloides PAL. Additional increases in thermal stability and protease resistance upon ligand binding may be due to enhanced interactions among the residues of the active site, possibly locking the active-site structure in place and stabilizing the tetramer. Examination of the A. variabilis C503S/C565S PAL structure, combined with analysis of its physical properties, provides

  16. The effect of cadmium on phenylalanine ammonia lyase activity and lipid peroxidation in pepper (Capsicum annuum L. seedlings

    Directory of Open Access Journals (Sweden)

    Esra Koç

    2015-04-01

    Full Text Available In this study, the effect on differrent concentrations (20, 40, 80µM ve 100 µM CdCl2 of cadmium (CdCl2 on the activity of phenylalanine ammonia-lyase (PAL and lipid peroxidation amount in leaf and stem of Kahramanmaraş- Hot (Capsicum annum L. pepper seedlings were researched. Activity of phenylalanine ammonia-lyase (PAL, the first enzyme in the phenylpropanoid biosynthetic pathway, was increased at 2 and 4 days in KM-Hot plants exposed to CdCl2 stress. The highest PAL activity was detected in 20 μM CdCl2 application, on the four day after the application in the leaves of KM-Hot pepper. Moreover, it was observed that treatment of pepper with Cd led to an increased the rate of lipid peroxidation (which is indicated by increasing MDA content in the leaf and stem tissues. The highest MDA content was detected in 80 μM CdCl2 application, on the four day after the application in the leaf tissues. These results suggest that the activation of PAL may be associated with increased production of MDA

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

    International Nuclear Information System (INIS)

    Nikolakakis, Kiel; Ohtaki, Akashi; Newton, Keith; Chworos, Arkadiusz; Sagermann, Martin

    2009-01-01

    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

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

    International Nuclear Information System (INIS)

    Riaz, A.; Tahir, M.I.

    2014-01-01

    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)

  19. Biochemical Evaluation of Phenylalanine Ammonia Lyase from Endemic Plant Cyathobasis fruticulosa (Bunge Aellen. for the Dietary Treatment of Phenylketonuria

    Directory of Open Access Journals (Sweden)

    Seda Şirin

    2016-01-01

    Full Text Available Enzyme substitution therapy with the phenylalanine ammonia lyase (PAL is a new approach to the treatment of patients with phenylketonuria (PKU. This enzyme is responsible for the conversion of phenylalanine to trans-cinnamic acid. We assessed the PAL enzyme of the endemic plant Cyathobasis fruticulosa (Bunge Aellen. for its possible role in the dietary treatment of PKU. The enzyme was found to have a high activity of (64.9±0.1 U/mg, with the optimum pH, temperature and buffer (Tris–HCl and L-phenylalanine concentration levels of pH=8.8, 37 °C and 100 mM, respectively. Optimum enzyme activity was achieved at pH=4.0 and 7.5, corresponding to pH levels of gastric and intestinal juice, and NaCl concentration of 200 mM. The purifi cation of the enzyme by 1.87-fold yielded an activity of 98.6 U/mg. PAL activities determined by HPLC analyses before and after purification were similar. Two protein bands, one at 70 and the other at 23 kDa, were determined by Western blot analysis of the enzyme. This enzyme is a potential candidate for serial production of dietary food and biotechnological products.

  20. Cadmium-induced changes in pigments, total phenolics, and phenylalanine ammonia-lyase activity in fronds of Azolla imbricata.

    Science.gov (United States)

    Dai, Ling-Peng; Xiong, Zhi-Ting; Huang, Yu; Li, Min-Jing

    2006-10-01

    This study was designed to examine the effects of cadmium on several color-related parameters (including chlorophyll, carotenoid, and anthocyanin), total phenolics, and phenylalanine ammonia-lyase (PAL) activity in an aquatic fern species Azolla imbricate (A. imbricata). Cd accumulation and effects in the fronds were closely related with Cd concentration in the growth medium. The fronds under 0.5 mg/L Cd treatment turned red on the 3rd day, and this color change also appeared under 0.05 and 0.1 mg/L Cd treatment on the 5th day. Correlated with the color change, the contents of chlorophyll and carotenoid in the fronds significantly decreased in the presence of high Cd concentrations, while the anthocyanin content increased during the experiment. Significant increase in total phenolics content and PAL activity were also detected during Cd treatment. The results suggested that the Cd-induced change in color of fronds might be due to the decrease in chlorophyll and carotenoid and the increase in anthocyanin. Anthocyanin, total phenolics and their biosynthesis-related PAL might play a role in detoxification of Cd in A. imbricata.

  1. [The relationship between activity and gene expression of phenylalanine ammonia-lyase and peel pitting in 'Fengjie' navel orange fruits].

    Science.gov (United States)

    Li, Zheng-Guo; Gao, Xue; Fan, Jing; Yang, Ying-Wu; Li, Dao-Gao; Kanellis, Angelos K

    2006-06-01

    Citrus fruit is prone to develop peel pitting during development and storage, which greatly decreases its fresh market value because of the deterioration of the peel. In the present study, we have examined the effect of different temperatures (15 degrees C and 4 degrees C), waxing and mechanical damage on the changes in the activity of phenylalanine ammonia-lyase (PAL) and the incidence of peel pitting in 'Fengjie' navel orange (Citrus sinensis Osbeck) fruits. The expression levels of PAL2, PAL6 genes in the peel during the development of peel pitting have been investigated through semi-quantitative PCR method. The incidence of peel pitting was greatly enhanced by waxing and mechanical damage and was decreased in lower temperature storage (4 degrees C) (Fig.1). Waxing and mechanical damage might be the important factors inducing peel pitting and suitable low temperature could decrease the incidence of this disease. The PAL activity increased during the whole storage period in accordance with the development of this pitting (Fig.2). The expression levels of PAL2 and PAL6 genes in damaged peel were higher than those in healthy peel and the expression of PAL2 is much more higher than that of PAL6 (Figs.4 and 5). The results suggested that the enzyme activity of PAL, along with the expression of PAL2 gene is highly related to this peel pitting occurred on 'Fengjie' navel orange fruits.

  2. Molecular and analysis of a phenylalanine ammonia-lyase gene (LrPAL2) from Lycoris radiata.

    Science.gov (United States)

    Jiang, Yumei; Xia, Bing; Liang, Lijian; Li, Xiaodan; Xu, Sheng; Peng, Feng; Wang, Ren

    2013-03-01

    Phenylalanine ammonia-lyase (PAL), the first enzyme of phenylpropanoid biosynthesis, participates in the biosynthesis of flavonoids, lignins, stilbenes and many other compounds. In this study, we cloned a 2,326 bp full-length PAL2 gene from Lycoris radiata by using degenerate oligonucleotide primer PCR (DOP-PCR) and the rapid amplification of cDNA ends method. The cDNA contains a 2,124 bp coding region encoding 707 amino acids. The LrPAL2 shares about 77.0 % nucleic acid identity and 83 % amino acid identity with LrPAL1. Furthermore, genome sequence analysis demonstrated that LrPAL2 gene contains one intron and two exons. The 5' flanking sequence of LrPAL2 was also cloned by self-formed adaptor PCR (SEFA-PCR), and a group of putative cis-acting elements such as TATA box, CAAT box, G box, TC-rich repeats, CGTCA motif and TCA-element were identified. The LrPAL2 was detected in all tissues examined, with high abundance in bulbs at leaf sprouting stage and in petals at blooming stage. Besides, LrPAL2 drastically responded to MJ, SNP and UV, moderately responded to GA and SA, and a little increased under wounding. Comparison of LrPAL2 expression and LrPAL1 expression demonstrated that LrPAL2 can be more significantly induced than LrPAL1 under the above treatments, and LrPAL2 transcripts accumulated prominently at blooming stage, especially in petals, while LrPAL1 transcripts did not accumulated significantly at blooming stage. All these results suggested that LrPAL2 might play distinct roles in different branches of the phenylpropanoid pathway.

  3. One-Pot Enzymatic Synthesis of D-Arylalanines Using Phenylalanine Ammonia Lyase and L-Amino Acid Deaminase.

    Science.gov (United States)

    Zhu, Longbao; Feng, Guoqiang; Ge, Fei; Song, Ping; Wang, Taotao; Liu, Yi; Tao, Yugui; Zhou, Zhemin

    2018-06-08

    The phenylalanine ammonia-lyase (AvPAL) from Anabaena variabilis catalyzes the amination of substituent trans-cinnamic acid (t-CA) to produce racemic D,L-enantiomer arylalanine mixture owing to its low stereoselectivity. To produce high optically pure D-arylalanine, a modified AvPAL with high D-selectivity is expected. Based on the analyses of catalytic mechanism and structure, the Asn347 residue in the active site was proposed to control stereoselectivity. Therefore, Asn347 was mutated to construct mutant AvPAL-N347A, the stereoselectivity of AvPAL-N347A for D-enantiomer arylalanine was 2.3-fold higher than that of wild-type AvPAL (WtPAL). Furthermore, the residual L-enantiomer product in reaction solution could be converted into the D-enantiomer product through stereoselective oxidation by PmLAAD and nonselective reduction by reducing agent NH 3 BH 3 . At optimal conditions, the conversion rate of t-CA and optical purity (enantiomeric excess (ee D )) of D-phenylalanine reached 82% and exceeded 99%, respectively. The two enzymes displayed activity toward a broad range of substrate and could be used to efficiently synthesize D-arylalanine with different groups on the phenyl ring. Among these D-arylalanines, the yield of m-nitro-D-phenylalanine was highest and reached 96%, and the ee D exceeded 99%. This one-pot synthesis using AvPAL and PmLAAD has prospects for industrial application.

  4. Bioproduction of L-Aspartic Acid and Cinnamic Acid by L-Aspartate Ammonia Lyase from Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Patel, Arti T; Akhani, Rekha C; Patel, Manisha J; Dedania, Samir R; Patel, Darshan H

    2017-06-01

    Aspartase (L-aspartate ammonia lyase, EC 4.3.1.1) catalyses the reversible amination and deamination of L-aspartic acid to fumaric acid which can be used to produce important biochemical. In this study, we have explored the characteristics of aspartase from Pseudomonas aeruginosa PAO1 (PA-AspA). To overproduce PA-AspA, the 1425-bp gene was introduced in Escherichia coli BL21 and purified. A 51.0-kDa protein was observed as a homogenous purified protein on SDS-PAGE. The enzyme was optimally active at pH 8.0 and 35 °C. PA-AspA has retained 56% activity after 7 days of incubation at 35 °C, which displays the hyperthermostablility characteristics of the enzyme. PA-AspA is activated in the presence of metal ions and Mg2+ is found to be most effective. Among the substrates tested for specificity of PA-AspA, L-phenylalanine (38.35 ± 2.68) showed the highest specific activity followed by L-aspartic acid (31.21 ± 3.31) and fumarate (5.42 ± 2.94). K m values for L-phenylalanine, L-aspartic acid and fumarate were 1.71 mM, 0.346 μM and 2 M, respectively. The catalytic efficiency (k cat /K m ) for L-aspartic acid (14.18 s -1  mM -1 ) was higher than that for L-phenylalanine (4.65 s -1  mM -1 ). For bioconversion, from an initial concentration of 1000 mM of fumarate and 30 mM of L-phenylalanine, PA-AspA was found to convert 395.31 μM L-aspartic acid and 3.47 mM cinnamic acid, respectively.

  5. Suppressed phenylalanine ammonia-lyase activity after heat shock in transgenic Nicotiana plumbaginifolia containing an Arabidopsis HSP18.2-parsley PAL2 chimera gene.

    Science.gov (United States)

    Moriwaki, M; Yamakawa, T; Washino, T; Kodama, T; Igarashi, Y

    1999-01-01

    The activity of phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) after heat shock (HS) in leaves and buds of transgenic Nicotiana plumbaginifolia containing an Arabidopsis HSP18.2 promoter-parsley phenylalanine ammonia-lyase 2 (HSP18.2-PAL2) chimera gene was examined. Immediately after HS treatment at 44 degrees C for 5 h, the PAL activity in both transgenic and normal (untransformed) plants was 35-38% lower than that before HS. At normal temperature (25-26 degrees C), the PAL activity recovered within 5 h of ending the HS treatment in normal plants, but not until 12-24 h in transgenic plants containing the HSP18.2-PAL2 gene. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed the presence of parsley PAL2 mRNA in transgenic plants, which remained for 8-12 h following 5-h HS at 44 degrees C; the mRNA was not observed before HS. The content of chlorogenic acid (CGA; 3-caffeoylquinic acid) decreased drastically 8-12 h after HS in transgenic plants, but only slightly in normal plants. Thus, the decrease in PAL activity accompanied by expression of the parsley PAL2 gene after HS treatment corresponded to the decrease in CGA synthesis. These results might be attributed to post-transcriptional degradation of endogenous PAL mRNA triggered by transcription of the transgene.

  6. Single-dose, subcutaneous recombinant phenylalanine ammonia lyase conjugated with polyethylene glycol in adult patients with phenylketonuria: an open-label, multicentre, phase 1 dose-escalation trial.

    Science.gov (United States)

    Longo, Nicola; Harding, Cary O; Burton, Barbara K; Grange, Dorothy K; Vockley, Jerry; Wasserstein, Melissa; Rice, Gregory M; Dorenbaum, Alejandro; Neuenburg, Jutta K; Musson, Donald G; Gu, Zhonghua; Sile, Saba

    2014-07-05

    Phenylketonuria is an inherited disease caused by impaired activity of phenylalanine hydroxylase, the enzyme that converts phenylalanine to tyrosine, leading to accumulation of phenylalanine and subsequent neurocognitive dysfunction. Phenylalanine ammonia lyase is a prokaryotic enzyme that converts phenylalanine to ammonia and trans-cinnamic acid. We aimed to assess the safety, tolerability, pharmacokinetic characteristics, and efficacy of recombinant Anabaena variabilis phenylalanine ammonia lyase (produced in Escherichia coli) conjugated with polyethylene glycol (rAvPAL-PEG) in reducing phenylalanine concentrations in adult patients with phenylketonuria. In this open-label, phase 1, multicentre trial, single subcutaneous injections of rAvPAL-PEG were given in escalating doses (0·001, 0·003, 0·010, 0·030, and 0·100 mg/kg) to adults with phenylketonuria. Participants aged 18 years or older with blood phenylalanine concentrations of 600 μmol/L or higher were recruited from among patients attending metabolic disease clinics in the USA. The primary endpoints were safety and tolerability of rAvPAL-PEG. Secondary endpoints were the pharmacokinetic characteristics of the drug and its effect on concentrations of phenylalanine. Participants and investigators were not masked to assigned dose group. This study is registered with ClinicalTrials.gov, number NCT00925054. 25 participants were recruited from seven centres between May 6, 2008, and April 15, 2009, with five participants assigned to each escalating dose group. All participants were included in the safety population. The most frequently reported adverse events were injection-site reactions and dizziness, which were self-limited and without sequelae. Two participants had serious adverse reactions to intramuscular medroxyprogesterone acetate, a drug that contains polyethylene glycol as an excipient. Three of five participants given the highest dose of rAvPAL-PEG (0·100 mg/kg) developed a generalised skin rash

  7. 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.

  8. Cloning and Expression Analysis of Phenylalanine Ammonia-Lyase Gene in the Mycelium and Fruit Body of the Edible Mushroom Flammulina velutipes

    Science.gov (United States)

    Yun, Yeo Hong; Koo, Ja Sun

    2015-01-01

    Phenylalanine ammonia-lyase (PAL) gene is known to be expressed in plants, and is involved in the differentiation, growth and synthesis of secondary metabolites. However, its expression in fungi remains to be explored. To understand its expression in mushroom fungi, the PAL gene of the edible mushroom Flammulina velutipes (Fvpal) was cloned and characterized. The cloned Fvpal consists of 2,175 bp, coding for a polypeptide containing 724 amino acids and having 11 introns. The translated amino acid sequence of Fvpal shares a high identity (66%) with that of ectomycorrhizal fungus Tricholoma matsutake. Distinctively, the Fvpal expression in the mycelium was higher in minimal medium supplemented with L-tyrosine than with other aromatic amino acids. During cultivation of the mushroom on sawdust medium, Fvpal expression in the fruit body correspondingly increased as the mushroom grew. In the fruiting body, Fvpal was expressed more in the stipe than in the pileus. These results suggest that F. velutipes PAL activity differs in the different organs of the mushroom. Overall, this is first report to show that the PAL gene expression is associated with mushroom growth in fungi. PMID:26539050

  9. DNA Methylation Influences Chlorogenic Acid Biosynthesis in Lonicera japonica by Mediating LjbZIP8 to Regulate Phenylalanine Ammonia-Lyase 2 Expression

    Directory of Open Access Journals (Sweden)

    Liangping Zha

    2017-07-01

    Full Text Available The content of active compounds differ in buds and flowers of Lonicera japonica (FLJ and L. japonica var. chinensis (rFLJ. Chlorogenic acid (CGAs were major active compounds of L. japonica and regarded as measurements for quality evaluation. However, little is known concerning the formation of active compounds at the molecular level. We quantified the major CGAs in FLJ and rFLJ, and found the concentrations of CGAs were higher in the buds of rFLJ than those of FLJ. Further analysis of CpG methylation of CGAs biosynthesis genes showed differences between FLJ and rFLJ in the 5′-UTR of phenylalanine ammonia-lyase 2 (PAL2. We identified 11 LjbZIP proteins and 24 rLjbZIP proteins with conserved basic leucine zipper domains, subcellular localization, and electrophoretic mobility shift assay showed that the transcription factor LjbZIP8 is a nuclear-localized protein that specifically binds to the G-box element of the LjPAL2 5′-UTR. Additionally, a transactivation assay and LjbZIP8 overexpression in transgenic tobacco indicated that LjbZIP8 could function as a repressor of transcription. Finally, treatment with 5-azacytidine decreased the transcription level of LjPAL2 and CGAs content in FLJ leaves. These results raise the possibility that DNA methylation might influence the recruitment of LjbZIP8, regulating PAL2 expression level and CGAs content in L. japonica.

  10. Structure and characterization of a cDNA clone for phenylalanine ammonia-lyase from cut-injured roots of sweet potato

    International Nuclear Information System (INIS)

    Tanaka, Yoshiyuki; Matsuoka, Makoto; Yamanoto, Naoki; Ohashi, Yuko; Kano-Murakami, Yuriko; Ozeki, Yoshihiro

    1989-01-01

    A cDNA clone for phenylalanine ammonia-lyase (PAL) induced in wounded sweet potato (Ipomoea batatas Lam.) root was obtained by immunoscreening a cDNA library. The protein produced in Escherichia coli cells containing the plasmid pPAL02 was indistinguishable from sweet potato PAL as judged by Ouchterlony double diffusion assays. The M r of its subunit was 77,000. The cells converted [ 14 C]-L-phenylalanine into [ 14 C]-t-cinnamic acid and PAL activity was detected in the homogenate of the cells. The activity was dependent on the presence of the pPAL02 plasmid DNA. The nucleotide sequence of the cDNA contained a 2,121-base pair (bp) open-reading frame capable of coding for a polypeptide with 707 amino acids (M r 77,137), a 22-bp 5'-noncoding region and a 207-bp 3'-noncoding region. The results suggest that the insert DNA fully encoded the amino acid sequence for sweet potato PAL that is induced by wounding. Comparison of the deduced amino acid sequence with that of a PAL cDNA fragment from Phaseolus vulgaris revealed 78.9% homology. The sequence from amino acid residues 258 to 494 was highly conserved, showing 90.7% homology

  11. Rhodotorulaglutinis phenylalanine/tyrosine ammonia lyase enzyme catalyzed synthesis of the methyl ester of para-hydroxycinnamic acid and its potential antibacterial activity

    Directory of Open Access Journals (Sweden)

    Marybeth C MacDonald

    2016-03-01

    Full Text Available 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.

  12. 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.

  13. 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.

    Science.gov (United States)

    Zhu, Longbao; Zhou, Li; Huang, Nan; Cui, Wenjing; Liu, Zhongmei; Xiao, Ke; Zhou, Zhemin

    2014-01-01

    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.

  14. Developmental role of phenylalanine-ammonia-lyase (PAL) and cinnamate 4-hydroxylase (C4H) genes during adventitious rooting of Juglans regia L. microshoots.

    Science.gov (United States)

    Cheniany, Monireh; Ganjeali, Ali

    2016-12-01

    Phenylalanine-ammonia-lyase and cinnamate-4-hydroxylase play important role in the phenylpropanoid pathway, which produces many biologically important secondary metabolites participating in normal plant development. Flavonol quercetin is the main representant of these compounds that has been identified in numerous Juglans spp. In this survey, the developmental expression patterns of PAL and C4H genes during in vitro rooting of two walnut cultivars 'Sunland' and 'Howard' was examined by RT-PCR. To understand the potential role in rooting, the changing pattern of endogenous content of quercetin was also analyzed by HPLC. The 'Sunland' with better capacity to root had more quercetin content during the "inductive phase" of rooting than 'Howard'. In each cultivar, the level of PAL transcripts showed the same behavior with the changing patterns of quercetin during root formation of microshoots. The positive correlation between the changes of quercetin and PAL-mRNA indicated that PAL gene may have an immediate effect on flavonoid pathway metabolites including quercetin. Although the behavioral change of C4H expression was similar in both cultivars during root formation (with significantly more level for 'Howard'), it was not coincide with the changes of quercerin concentrations. Our results showed that C4H function is important for the normal development, but its transcriptional regulation does not correlate with quercetin as an efficient phenolic compound for walnut rhizogenesis.

  15. Expression and enzymatic activity of phenylalanine ammonia-lyase and p-coumarate 3-hydroxylase in mango (Mangifera indica 'Ataulfo') during ripening.

    Science.gov (United States)

    Palafox-Carlos, H; Contreras-Vergara, C A; Muhlia-Almazán, A; Islas-Osuna, M A; González-Aguilar, G A

    2014-05-16

    Phenylalanine ammonia lyase (PAL) and p-coumarate 3-hydroxylase (C3H) are key enzymes in the phenylpropanoid pathway. The relative expression of PAL and C3H was evaluated in mango fruit cultivar 'Ataulfo' in four ripening stages (RS1, RS2, RS3, and RS4) by quantitative polymerase chain reaction. In addition, enzyme activity of PAL and C3H was determined in mango fruits during ripening. The PAL levels were downregulated at the RS2 and RS3 stages, while C3H levels were upregulated in fruits only at RS3. The enzyme activity of PAL followed a pattern that was different from that of the PAL expression, thus suggesting regulation at several levels. For C3H, a regulation at the transcriptional level is suggested because a similar pattern was revealed by its activity and transcript level. In this study, the complexity of secondary metabolite biosynthesis regulation is emphasized because PAL and C3H enzymes are involved in the biosynthesis of several secondary metabolites that are active during all mango ripening stages.

  16. A phenylalanine ammonia-lyase ortholog (PkPAL1) from Picrorhiza kurrooa Royle ex. Benth: molecular cloning, promoter analysis and response to biotic and abiotic elicitors.

    Science.gov (United States)

    Bhat, Wajid Waheed; Razdan, Sumeer; Rana, Satiander; Dhar, Niha; Wani, Tariq Ahmad; Qazi, Parvaiz; Vishwakarma, Ram; Lattoo, Surrinder K

    2014-09-01

    Picrorhiza kurrooa Royle ex Benth. is a highly reputed medicinal herb utilised in the preparation of a number of herbal drug formulations, principally due to the presence of novel monoterpene iridoid glycosides kenned as picrosides. Phenylalanine ammonia-lyase catalyses an important rate-limiting step in phenylpropanoid pathway and supplies precursors like cinnamic acid, vanillic acid, ferulic acid, etc., to a variety of secondary metabolites including picrosides. The imperilled status of P. kurrooa coupled with lack of information regarding biogenesis of picrosides necessitates deciphering the biosynthetic pathway for picrosides. In the present study, a PAL gene, designated PkPAL1 was isolated from P. kurrooa. The cDNA is 2312 bp in length, consisting of an ORF of 2142 bp encoding for a 713 amino acid protein having a predicted molecular weight of 77.66 kDa and an isoelectric point of pH 6.82. qRT-PCR analysis of various tissues of P. kurrooa showed that PkPAL1 transcript levels were highest in the leaves, consistent with picroside accumulation pattern. Using Genome walking, a 718 bp promoter region was also isolated resulting in identification of distinct cis-regulatory elements including TGA-element, TGACG-motif, CGTCA-motif, etc. qRT-PCR indicated up-regulation of PkPAL1 by methyl jasmonate, salicylic acid, 2,4-dicholorophenoxy acetic acid and UV-B elicitations that corroborated positively with the identified cis-elements within the promoter region. Moreover, altitude was found to have a positive effect on the PkPAL1 transcript levels, driving the expression of PkPAL1 abundantly. Based on docking analysis, we identified eight residues as potentially essential for substrate binding in PkPAL1. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Regulation of a phenylalanine ammonia lyase (BbPAL) by calmodulin in response to environmental changes in the entomopathogenic fungus Beauveria bassiana.

    Science.gov (United States)

    Kim, Jiyoung; Park, Hyesung; Han, Jae-Gu; Oh, Junsang; Choi, Hyung-Kyoon; Kim, Seong Hwan; Sung, Gi-Ho

    2015-11-01

    Phenylalanine ammonia lyase (PAL, E.C. 4.3.1.5) catalyses the deamination of L -phenylalanine to trans-cinnamic acid and ammonia, facilitating a critical step in the phenylpropanoid pathway that produces a variety of secondary metabolites. In this study, we isolated BbPAL gene in the entomopathogenic fungus Beauveria bassiana. According to multiple sequence alignment, homology modelling and in vitro PAL activity, we demonstrated that BbPAL acts as a typical PAL enzyme in B. bassiana. BbPAL interacted with calmodulin (CaM) in vitro and in vivo, indicating that BbPAL is a novel CaM-binding protein. The functional role of CaM in BbPAL action was to negatively regulate the BbPAL activity in B. bassiana. High-performance liquid chromatography analysis revealed that L -phenylalanine was reduced and trans-cinnamic acid was increased in response to the CaM inhibitor W-7. Dark conditions suppressed BbPAL activity in B. bassiana, compared with light. In addition, heat and cold stresses inhibited BbPAL activity in B. bassiana. Interestingly, these negative effects of BbPAL activity by dark, heat and cold conditions were recovered by W-7 treatment, suggesting that the inhibitory mechanism is mediated through stimulation of CaM activity. Therefore, this work suggests that BbPAL plays a role in the phenylpropanoid pathway mediated by environmental stimuli via the CaM signalling pathway. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

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

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    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.

  19. 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

  20. Wound-induced ethylene synthesis and expression and formation of 1-aminocyclopropane-1-carboxylate (ACC) synthase, ACC oxidase, phenylalanine ammonia-lyase, and peroxidase in wounded mesocarp tissue of Cucurbita maxima.

    Science.gov (United States)

    Kato, M; Hayakawa, Y; Hyodo, H; Ikoma, Y; Yano, M

    2000-04-01

    1-Aminocyclopropane-1-carboxylate (ACC) synthase was rapidly induced in mesocarp tissue of Cucurbita maxima after wounding in the cut surface layer in 1 mm thickness (ca. 9 cells) (first layer) in both the enzyme activity and the levels of transcript. This led to a rapid accumulation of ACC and hence ethylene production. In the inside tissue (1-2 mm) (second layer), no significant induction of ACC synthase was observed, which resulted in a low level of ACC, although ethylene was evolved at a much lower rate than the first one. In contrast to ACC synthase, ACC oxidase was induced markedly in both the first and second layers and the development of its activity and the levels of mRNA remained high until later stages. It was considered that wound ethylene was closely associated with the development of ACC oxidase, since 2,5-norbornadiene (NBD), an inhibitor of ethylene action, substantially suppressed it. Phenylalanine ammonia-lyase (PAL) greatly increased in activity after wounding similarly to that of ACC synthase, in which increase in PAL activity occurred predominantly in the first layer. Induction of peroxidase activity after wounding had a close correlation in profile with that of ACC oxidase in that marked increases in the activity were observed in both the first and second layers and were strongly suppressed by NBD application. Four peroxidase isozymes were found by PAGE, among which a fraction was newly detected after wounding.

  1. 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.

  2. Phenylalanine ammonia lyase from Arabidopsis thaliana (AtPAL2): A potent MIO-enzyme for the synthesis of non-canonical aromatic alpha-amino acids: Part I: Comparative characterization to the enzymes from Petroselinum crispum (PcPAL1) and Rhodosporidium toruloides (RtPAL).

    Science.gov (United States)

    Dreßen, Alana; Hilberath, Thomas; Mackfeld, Ursula; Billmeier, Arne; Rudat, Jens; Pohl, Martina

    2017-09-20

    Phenylalanine ammonia lyase (PAL) from Arabidopsis thaliana (AtPAL2) was comparatively characterized to the well-studied enzyme from parsley (PcPAL1) and Rhodosporidium toruloides (RtPAL) with respect to kinetic parameters for the deamination and the amination reaction, pH- and temperature optima and the substrate range of the amination reaction. Whereas both plant enzymes are specific for phenylalanine, the bifunctional enzyme from Rhodosporidium toruloides shows K M -values for L-Phe and L-Tyr in the same order of magnitude and, compared to both plant enzymes, a 10-15-fold higher activity. At 30°C all enzymes were sufficiently stable with half-lives of 3.4days (PcPAL1), 4.6days (AtPAL2) and 9.7days (RtPAL/TAL). Very good results for the amination of various trans-cinnamic acid derivatives were obtained using E. coli cells as whole cell biocatalysts in ammonium carbonate buffer. Investigation of the substrate ranges gave interesting results for the newly tested enzymes from A. thaliana and R. toruloides. Only the latter accepts besides 4-hydroxy-CA also 3-methoxy-4-hydroxy-CA as a substrate, which is an interesting intermediate for the formation of pharmaceutically relevant L-Dopa. AtPAL2 is a very good catalyst for the formation of (S)-3-F-Phe, (S)-4-F-Phe and (S)-2-Cl-Phe. Such non-canonical amino acids are valuable building blocks for the formation of various drug molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Phenylalanine Ammonia Lyase Activity in Stem of Pepper (Capsicum annuum L.) Infected by Phytophthora capsici L.

    OpenAIRE

    KOC, Esra; USTUN, Ayşen Sulun

    2012-01-01

    In this study, PAL activity in stems of pepper (Capsicum annuum L.) plants infected by the root rot pathogen Phytophthora capsici-22 in a resistant (PM-702) and two susceptible (Kahramanmaraş-Hot (KM-Hot) and Demre-8) cultivar were studied. The response of the PAL activity in the resistant cultivar was faster and higher than in the susceptible cultivars (p < 0.01). The increase in production of  PAL upon Phytophthora capsici-22 were higher in the infected plants compared to the non-in...

  4. Virus-induced gene silencing of WRKY53 and an inducible phenylalanine ammonia-lyase in wheat reduces aphid resistance

    Science.gov (United States)

    Although several wheat genes differentially expressed during the Russian wheat aphid resistance response have recently been identified, their requirement for and specific role in resistance remain unclear. Progress in wheat-aphid interaction research is hampered by inadequate collections of mutant g...

  5. Electromagnetic Field Effects on Production of Salicylic Acid and Phenylalanine ammonia lyase in Tobacco Infected with Potato Virus X (PVX

    Directory of Open Access Journals (Sweden)

    amin radmard titkanlo

    2018-02-01

    Full Text Available Introduction: Potato virus x (PVX is one of the most devastating viruses in the fields of tobacco and no effective method to control the virus has been provided yet. Magnetism is known as one of the environmental stresses that can directly or indirectly affect the plants, especially plants under stress. The magnetic fields can have beneficial affects plants. Materials and Methods: In the present study to investigate the effects of electromagnetic fields on PVX control, an experiment based on completely randomized design with eleven treatments (10, 50 and 90 mT in a period of 60, 90 and 120 minutes on tobacco seedlings infected with the virus and two control, and the other one is free from analog infected with the virus in tobacco seedlings carried on six repeats.. After inoculation at the four-leaf stage and after 14 days, the amount of turbidity virus infection rate is calculated and then ensure equality of tobacco seedlings, where the electromagnetic device. 30 days after applying an electromagnetic field analysis of the results of ELISA test two samples were tested with antisera Chndhmsanh of PVX. The amount of salicylic acid and the enzyme phenylalanine ammonia in systemic acquired resistance and plant defense mechanisms are involved, the treatments were measured, for evaluation of HPLC as salicylic acid and phenylalanine ammonia-based assessment of trans-cinnamic acid was used. Results and Discussion: Statistical analysis ELISA test results revealed that there is a significant difference between treatments 0/05. So that the treatment was a no pollution treatment and 11 who were infected but had not been exposed to the electromagnetic field had a significant difference compared to other treatments, among the treatments that were exposed to the electromagnetic field treatment 8 (100 mT, 120 minutes showed the lowest OD in ELISA and later treatment 7 (50 mT and 60 minutes was the lowest OD, the two treatments were observed in less than two OD. If the treatment number 11, OD (2/85 and in pollution-free treatment that was an OD (0/35 was observed. The OD also in other treatments were not exposed between 2.00 to 2.46 were visible. The results showed that the treatment 11 (infected control actually infected treatment that has not been exposed, and treatment 8 is the most desirable treatment for a reduction in the OD, the difference in the OD are available 0/98. The results suggest that the electromagnetic field decreases the amount of OD in tobacco seedlings are infected with PVX. Researchers said electromagnetic field growth rate and the number of spores grown in three species are affected. In another study, it was found that the impact on dry and wet mycorrhiza. The electromagnetic field decreases witches' broom disease infected lemon trees that were probably due to the decline phytoplasmas in plant tissues. Another study on the antibacterial effects of electromagnetic fields on Serratia marcescens was conducted, which resulted in the inhibition of bacterial growth. The results of salicylic acid and PAL determine the tobacco crop treatments, there are significant differences in the level of 0/05. So that treatment (7 (50 mT, 60 min the highest salicylic acid and treatment 1 (control non-infected showed the lowest rates. Also, reviews PAL treatment and treatment (7 most (1 (see non-polluting had the lowest. In fact, with the arrival of the pathogen to the host salicylic acid and phenylalanine ammonia will increase. But the electromagnetic stress in some treatments of both traits, from infected plants, should take over. However, some treatments less than 11 treatments (infection control is (but treatment Salicylic acid (4 was less than healthy plant. Interestingly, in both treatments was the highest for both traits in treatments of 7, 6 and 5, respectively. Pre-plant treatments with salicylic acid caused a significant increase in the PAL activity, which indicates the role of these enzymes in plant defense mechanism, the researchers concluded that electromagnetic frequency is very low, possibly because of the resistance of tobacco to TMV and increased Ca2+ signaling pathway involving PAL and ODC hormones in plants. Conclusions: Comparing results of ELISA plants that had been under different electromagnetic fields the survey showed that 11 infected untreated control treatment without exposure possession was the highest infection. While treatment 8 (100 mT and 120 minutes and 7 (50 mT for 60 minutes showed the least amount of turbidity virus. Also in measuring hormone salicylic acid and PAL significant difference between treatments in both studies showed that treatment trait No. 7 in both traits were seen as the highest value. These results suggest a positive effect in reducing turbidity electromagnetic virus, an increase of salicylic acid and phenylalanine ammonia enzymes, hormones and enzymes that are involved in plant defense mechanisms as well.

  6. Relationship between browning and the activities of polyphenol oxidase and phenylalanine ammonia lyase in banana peel during low temperature storage

    NARCIS (Netherlands)

    Nguyen, T.B.T.; Ketsa, S.; Doorn, van W.G.

    2003-01-01

    Kluai Khai (Musa AA Group) and Kluai Hom Thong (Musa AAA Group) bananas were stored at 6 and 10 °C. Visible chilling injury (CI) in the peel, mainly browning, occurred at both temperatures, but more so at 6 °C, and without significant differences between the cultivars. At the time of harvest, total

  7. Browse Title Index

    African Journals Online (AJOL)

    Items 101 - 150 of 1010 ... Vol 26, No 1 (2018), Characterisation of Phaseolus coccineus interspecific germplasm accessions for disease resistance, grain market class and ... Vol 20, No 2 (2012), Comparative activities of phenylalanine ammonia-lyase and tyrosine ammonia-lyase and phenolic compounds accumulated in ...

  8. ORF Alignment: NC_000921 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_000921 gi|15611661 >1vdkA 1 460 2 461 e-141 ... ref|NP_223312.1| ASPARTATE AMMONIA...-LYASE [Helicobacter pylori J99] gb|AAD06167.1| ... ASPARTATE AMMONIA-LYASE [Helicobacter pylori J99

  9. ORF Alignment: NC_005090 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_005090 gi|34557077 >1vdkA 1 459 5 463 e-135 ... ref|NP_906892.1| ASPARTATE AMMONIA...-LYASE [Wolinella succinogenes DSM 1740] ... emb|CAE09792.1| ASPARTATE AMMONIA-LYASE [Wolinella ...

  10. ORF Alignment: NC_003318 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_003318 gi|17988713 >1gkpA 3 425 8 405 2e-19 ... ref|NP_541346.1| IMIDAZOLONEPROPIONASE / HISTIDINE AMMONIA...-LYASE [Brucella ... melitensis 16M] gb|AAL53610.1| IMIDAZOLONEPROPIONASE / ... HISTIDINE AMMON...IA-LYASE [Brucella melitensis 16M] ... pir||AG3555 histidine ammonia-lyase (

  11. Dicty_cDB: SSL363 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ichosuri cDNA 5' similar to SW:HUTH_CAEEL Q20502 PROBABLE HISTIDINE AMMONIA-LYASE...W:HUTH_CAEEL Q20502 PROBABLE HISTIDINE AMMONIA-LYASE ;, mRNA sequence. 44 1.4 1 dna update 2003. 9.10 Homolo

  12. ORF Alignment: NC_004311 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_004311 gi|23500656 >1gkpA 3 425 8 405 2e-19 ... ref|NP_541346.1| IMIDAZOLONEPROPIONASE / HISTIDINE AMMONIA...-LYASE [Brucella ... melitensis 16M] gb|AAL53610.1| IMIDAZOLONEPROPIONASE / ... HISTIDINE AMMON...IA-LYASE [Brucella melitensis 16M] ... pir||AG3555 histidine ammonia-lyase (

  13. ORF Alignment: NC_003047 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_003047 gi|15966456 >1gkmA 2 501 3 499 e-107 ... emb|CAC47282.1| PUTATIVE HISTIDINE AMMONIA...-LYASE PROTEIN [Sinorhizobium meliloti] ... ref|NP_386809.1| PUTATIVE HISTIDINE AMMONIA-LYASE

  14. ORF Alignment: NC_003317 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_003317 gi|17986393 >1vdkA 1 459 12 469 e-123 ... gb|AAL51291.1| ASPARTATE AMMONIA-...LYASE [Brucella melitensis 16M] ref|NP_539027.1| ... ASPARTATE AMMONIA-LYASE [Brucella melitensis 16M

  15. 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

  16. 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).

  17. 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

  18. Biochemical studies on the Combination of Bemul-wax and Calcium ...

    African Journals Online (AJOL)

    Afolabi S

    2011-04-04

    Apr 4, 2011 ... coating combined with calcium chloride treatment ... storage methods for sweet potatoes are by leaving the ..... Phenylalanine ammonia lyase activity of treated sweet potato at ambient temperature ..... Theme: Innovative.

  19. Biotechnological applications for rosmarinic acid production in plant

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-29

    Dec 29, 2008 ... tion and media optimization are the methods applied for improving ... lanine ammonia-lyase and tyrosine aminotransferase, the two entry point enzymes of the rosmarinic acid biosynthesis pathway. .... As determined by HPLC,.

  20. Download this PDF file

    African Journals Online (AJOL)

    amino acids analysis (Especially for the free amino acids), this formula was then analyzed for .... Methods: Skim milk hydrolysates were pre-. 1. pared by two enzymes: purified. Protease ...... recombinant phenylalanine ammonia lyase. Proc.

  1. Physiological mechanism of resistance to anthracnose of different ...

    African Journals Online (AJOL)

    However, enzyme activity of resistant cultivars improved markedly after pathogen inoculation, while those of susceptible cultivars did not change. This study broadens the understanding of the mechanisms of disease resistance in Camellia. Keywords: Anthracnose, Camellia oleifera, phenylalanine ammonia lyase, ...

  2. Isolation and amino acid sequence of a dehydratase acting on d-erythro-3-hydroxyaspartate from Pseudomonas sp. N99, and its application in the production of optically active 3-hydroxyaspartate.

    Science.gov (United States)

    Nagano, Hiroyuki; Shibano, Kana; Matsumoto, Yu; Yokota, Atsushi; Wada, Masaru

    2017-06-01

    An enzyme catalyzing the ammonia-lyase reaction for the conversion of d-erythro-3-hydroxyaspartate to oxaloacetate was purified from the cell-free extract of a soil-isolated bacterium Pseudomonas sp. N99. The enzyme exhibited ammonia-lyase activity toward l-threo-3-hydroxyaspartate and d-erythro-3-hydroxyaspartate, but not toward other 3-hydroxyaspartate isomers. The deduced amino acid sequence of the enzyme, which belongs to the serine/threonine dehydratase family, shows similarity to the sequence of l-threo-3-hydroxyaspartate ammonia-lyase (EC 4.3.1.16) from Pseudomonas sp. T62 (74%) and Saccharomyces cerevisiae (64%) and serine racemase from Schizosaccharomyces pombe (65%). These results suggest that the enzyme is similar to l-threo-3-hydroxyaspartate ammonia-lyase from Pseudomonas sp. T62, which does not act on d-erythro-3-hydroxyaspartate. We also then used the recombinant enzyme expressed in Escherichia coli to produce optically pure l-erythro-3-hydroxyaspartate and d-threo-3-hydroxyaspartate from the corresponding dl-racemic mixtures. The enzymatic resolution reported here is one of the simplest and the first enzymatic method that can be used for obtaining optically pure l-erythro-3-hydroxyaspartate.

  3. 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...

  4. Molecular cloning, characterization and expression of phenylalanine ...

    African Journals Online (AJOL)

    A full-length cDNA and genomic DNA of phenylalanine ammonia-lyase gene, which catalyzes the first step in the flavonoid biosynthetic pathway, were isolated from Ginkgo biloba for the first time (designated as GbPAL, GenBank Accession No. EU071050). The cDNA and genomic DNA sequences of GbPAL were the same, ...

  5. Potential effects of plant growth promoting rhizobacteria ...

    African Journals Online (AJOL)

    Damping off caused by Sclerotium rolfsii on cowpea results in yield losses with serious socioeconomic implication. Induction of defense responses by plant growth promoting rhizobacteria (PGPR) is largely associated with the production of defense enzyme phenyl ammonia lyase (PAL) and oxidative enzymes like ...

  6. Determination of specific growth stages of plant cell suspension cultures by monitoring conductivity changes in the medium.

    Science.gov (United States)

    Hahlbrock, K; Ebel, J; Oaks, A; Auden, J; Liersch, M

    1974-03-01

    Conductivity changes in the medium of cultured soybean (Glycine max L.) cells were shown to be strictly correlated with nitrate uptake and growth of the cultures. A continuous record of the conductivity was used as a simple and reliable method of determining specific growth stages and concomitant peaks in the activities of nitrate reductase and phenylalanine ammonia-lyase.

  7. Biotechnology of humified materials obtained from vermicomposts ...

    African Journals Online (AJOL)

    PERSON

    2013-02-13

    Feb 13, 2013 ... Techniques for determining the structure of HS have been particularly useful for .... Step 6: Attempted introduction of the technologies into agro- industrial and .... rice plants stimulated several enzymatic mechanisms associated with the ... ammonia-lyase (PAL) were stimulated, resulting in increased proline ...

  8. ORF Alignment: NC_003295 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_003295 gi|17547365 >1gkmA 3 497 10 504 e-143 ... emb|CAD16353.1| PROBABLE HISTIDINE AMMONIA...-LYASE (HISTIDASE) PROTEIN [Ralstonia ... solanacearum] ref|NP_520767.1| PROBABLE HISTIDINE ... AMMONIA

  9. ORF Alignment: NC_003296 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_003296 gi|17548586 >1gkmA 10 504 26 526 e-118 ... ref|NP_521926.1| PROBABLE HISTIDINE AMMONIA...-LYASE PROTEIN [Ralstonia solanacearum ... GMI1000] emb|CAD17516.1| PROBABLE HISTIDINE ... AMMONIA

  10. ORF Alignment: NC_003450 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_003450 gi|19552717 >1vdkA 1 459 57 516 e-127 ... ref|YP_225787.1| ASPARTATE AMMONIA...ynebacterium glutamicum ATCC 13032] emb|CAF21511.1| ... ASPARTATE AMMONIA-LYASE (ASPARTASE) [Coryneba

  11. Production of manganese peroxidase by white rot fungi from potato ...

    African Journals Online (AJOL)

    phenylalanine and L-tyrosine blocked the MnP biosynthetic pathway. Ammonium ion released from the L-phenylalanine by the L-phenylalanine ammonia-lyase participated in the repression of the MnP biosynthetic pathway of the strain L-25.

  12. Plant hormone interaction and phenolic metabolism in the regulation of russet spotting in iceberg lettuce.

    Science.gov (United States)

    Ke, D; Saltveit, M E

    1988-12-01

    Russet spotting (RS) is a physiological disorder induced in iceberg lettuce (Lactuca sativa L.) by exposure to parts per million levels of ethylene at 5 +/- 2 degrees C. Ethylene induced phenylalanine ammonia-lyase and ionically bound peroxidase activities that correlated with development of RS symptoms. The ethylene-treated tissue had significantly higher lignin content than air control tissue with lignification localized in walls of RS-affected cells. Ethylene also caused the accumulation of the flavonoids (+)catechin and (-)epicatechin and the chlorogenic acid derivatives 3-caffeoyl-quinic acid, 3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid. These soluble phenolic compounds were readily oxidized to brown substances by polyphenol oxidase isolated from RS tissue. Ethylene substantially increased ionically bound indole-3-acetic acid (IAA) oxidase activity, while IAA application greatly reduced ethylene-induced phenylalanine ammonia-lyase, peroxidase, and IAA oxidase activities, soluble phenolic content, and RS development.

  13. Genetically engineering Synechocystis sp. Pasteur Culture Collection 6803 for the sustainable production of the plant secondary metabolite p-coumaric acid.

    Science.gov (United States)

    Xue, Yong; Zhang, Yan; Cheng, Dan; Daddy, Soumana; He, Qingfang

    2014-07-01

    p-Coumaric acid is the precursor of phenylpropanoids, which are plant secondary metabolites that are beneficial to human health. Tyrosine ammonia lyase catalyzes the production of p-coumaric acid from tyrosine. Because of their photosynthetic ability and biosynthetic versatility, cyanobacteria are promising candidates for the production of certain plant metabolites, including phenylpropanoids. Here, we produced p-coumaric acid in a strain of transgenic cyanobacterium Synechocystis sp. Pasteur Culture Collection 6803 (hereafter Synechocystis 6803). Whereas a strain of Synechocystis 6803 genetically engineered to express sam8, a tyrosine ammonia lyase gene from the actinomycete Saccharothrix espanaensis, accumulated little or no p-coumaric acid, a strain that both expressed sam8 and lacked slr1573, a native hypothetical gene shown here to encode a laccase that oxidizes polyphenols, produced ∼82.6 mg/L p-coumaric acid, which was readily purified from the growth medium.

  14. Evaluation of pal activity, phenolic and flavonoid contents in three pistachio ( Pistacia vera L. ) cultivars grafted onto three different rootstocks

    OpenAIRE

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

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

    International Nuclear Information System (INIS)

    Jensen, R.A.

    1983-01-01

    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

  16. Local and systemic hormonal responses in pepper leaves during compatible and incompatible pepper-tobamovirus interactions

    Czech Academy of Sciences Publication Activity Database

    Dziurka, M.; Janeczko, A.; Juhasz, C.; Gullner, G.; Oklešťková, Jana; Novák, Ondřej; Saja, D.; Skoczowski, A.; Tobias, I.; Barna, B.

    2016-01-01

    Roč. 109, DEC (2016), s. 355-364 ISSN 0981-9428 R&D Projects: GA ČR GA14-34792S Institutional support: RVO:61389030 Keywords : tobacco-mosaic-virus * pathogenesis-related proteins * salicylic-acid * abscisic-acid * acquired- resistance * disease resistance * nicotiana-benthamiana * arabidopsis-thaliana * defense response * immune-responses * Brassinosteroids * Ethylene * Hormone * Pepper * Phenylalanine ammonia lyase * Progesterone * Salicylic acid * Tobamovirus Subject RIV: EF - Botanics Impact factor: 2.724, year: 2016

  17. 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

  18. 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 - others:GA ČR(CZ) GA525/07/0338; GA MŠk(CZ) ED1.1.00/02.0068 Program:GA; ED Institutional research plan: CEZ:AV0Z50380511 Keywords : Cinnamic acid * Mineral nutrients * Phenylalanine ammonia-lyase Subject RIV: ED - Physiology Impact factor: 2.775, year: 2012

  19. Highly Atom Economic Synthesis of d?2?Aminobutyric Acid through an In?Vitro Tri?enzymatic Catalytic System

    OpenAIRE

    Chen, Xi; Cui, Yunfeng; Cheng, Xinkuan; Feng, Jinhui; Wu, Qiaqing; Zhu, Dunming

    2017-01-01

    Abstract d?2?Aminobutyric acid is an unnatural amino acid serving as an important intermediate in pharmaceutical production. Developing a synthetic method that uses cheaper starting materials and produces less by?product is a pressing demand. A tri?enzymatic catalytic system, which is composed of l?threonine ammonia lyase (l?TAL), d?amino acid dehydrogenase (d?AADH), and formate dehydrogenase (FDH), has thus been developed for the synthesis of d?2?aminobutyric acid with high optical purity. I...

  20. Dicty_cDB: Contig-U09447-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 1( AB300202 |pid:none) Ephedra sinica Espal4 mRNA for phe... 100 1e-19 AB283036_1( AB283036 |pid:none) Lotus..... 99 1e-19 ( P45734 ) RecName: Full=Phenylalanine ammonia-lyase; EC=... 99 1e-19 AB300201_1( AB300201 |pid:none) Ephedra sinica Espa...9 complet... 99 2e-19 AB300199_1( AB300199 |pid:none) Ephedra sinica Espal1 mRNA for phe... 99 2e-19 AY32108

  1. 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)

    Wellmann, E.; Hrazdina, G.; Grisebach, H.

    1976-01-01

    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)

  2. 1sn06-56 Dogbo.p65

    African Journals Online (AJOL)

    Sci-Nat

    résistantes aux microorganismes. ... la lumière naturelle. La photopériode au cours de l'expérimentation a varié entre 12 h et 13 h (mai, juin, juillet 2005) et la température entre 28 °C et. 32 °C. La ..... Tableau 1: Effets de l'acide salicylique sur l'activité de la phénylalanine ammonia-lyase (PAL) dans les feuilles de plants de ...

  3. 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 (Ppineapple was significantly (Ppineapple. 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. Copyright © 2016. Published by Elsevier Ltd.

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

    DEFF Research Database (Denmark)

    2006-01-01

    A from said 4-coumaric acid, and resveratrol synthase (VST) produces said resveratrol from said 4- coumaroyl CoA, or in which L-phenylalanine- or tyrosine- ammonia lyase (PAL/TAL) produces 4-coumaric acid, 4- coumarate-CoA ligase (4CL) produces 4-coumaroyl CoA from said 4-coumaric acid, and resveratrol...... synthase (VST) produces said resveratrol from said 4-coumaroyl CoA. The micro-organism may be a yeast, fungus or bacterium including Saccharomyces cerevisiae, E. coli, Lactococcus lactis, Aspergillus niger, or Aspergillus oryzae....

  5. 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

    2016-06-08

    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.

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

    International Nuclear Information System (INIS)

    Hanotel, L.; Fleuriet, A.; Boisseau, P.

    1995-01-01

    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

  7. Thiamine primed defense provides reliable alternative to systemic fungicide carbendazim against sheath blight disease in rice (Oryza sativa L.).

    Science.gov (United States)

    Bahuguna, Rajeev Nayan; Joshi, Rohit; Shukla, Alok; Pandey, Mayank; Kumar, J

    2012-08-01

    A novel pathogen defense strategy by thiamine priming was evaluated for its efficacy against sheath blight pathogen, Rhizoctonia solani AG-1A, of rice and compared with that of systemic fungicide, carbendazim (BCM). Seeds of semidwarf, high yielding, basmati rice variety Vasumati were treated with thiamine (50 mM) and BCM (4 mM). The pot cultured plants were challenge inoculated with R. solani after 40 days of sowing and effect of thiamine and BCM on rice growth and yield traits was examined. Higher hydrogen peroxide content, total phenolics accumulation, phenylalanine ammonia lyase (PAL) activity and superoxide dismutase (SOD) activity under thiamine treatment displayed elevated level of systemic resistance, which was further augmented under challenging pathogen infection. High transcript level of phenylalanine ammonia lyase (PAL) and manganese superoxide dismutase (MnSOD) validated mode of thiamine primed defense. Though minimum disease severity was observed under BCM treatment, thiamine produced comparable results, with 18.12 per cent lower efficacy. Along with fortifying defense components and minor influence on photosynthetic pigments and nitrate reductase (NR) activity, thiamine treatment significantly reduced pathogen-induced loss in photosynthesis, stomatal conductance, chlorophyll fluorescence, NR activity and NR transcript level. Physiological traits affected under pathogen infection were found signatory for characterizing plant's response under disease and were detectable at early stage of infection. These findings provide a novel paradigm for developing alternative, environmentally safe strategies to control plant diseases. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  8. Alleviation of isoproturon toxicity to wheat by exogenous application of glutathione.

    Science.gov (United States)

    Nemat Alla, Mamdouh M; Hassan, Nemat M

    2014-06-01

    Treatment with the recommended field dose of isoproturon to 7-d-old wheat seedlings significantly decreased shoot height, fresh and dry weights during the subsequent 15days. Meanwhile contents of carotenoids, chlorophylls and anthocyanin as well as activities of δ-aminolevulinate dehydratase (ALA-D), phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) were significantly inhibited. On the other hand, the herbicide significantly increased malondialdehyde (MDA), a naturally occurring product of lipid peroxidation and H2O2, while it significantly decreased the contents of glutathione (GSH) and ascorbic acid (AsA) and reduced the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX). These findings indicate an induction of a stress status in wheat seedlings following isoproturon treatment. However, exogenous GSH appeared to limit the toxic effects of isoproturon and seemed to overcome this stress status. Most likely, contents of pigment and activities of enzymes were raised to approximate control levels. Moreover, antioxidants were elevated and the oxidative stress indices seemed to be alleviated by GSH application. These results indicate that exogenous GSH enhances enzymatic and nonenzymatic antioxidants to alleviate the effects of isoproturon. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Low-temperature conditioning of "seed" cloves enhances the expression of phenolic metabolism related genes and anthocyanin content in 'Coreano' garlic (Allium sativum) during plant development.

    Science.gov (United States)

    Dufoo-Hurtado, Miguel D; Zavala-Gutiérrez, Karla G; Cao, Cong-Mei; Cisneros-Zevallos, Luis; Guevara-González, Ramón G; Torres-Pacheco, Irineo; Vázquez-Barrios, M Estela; Rivera-Pastrana, Dulce M; Mercado-Silva, Edmundo M

    2013-11-06

    Low-temperature conditioning of garlic "seed" cloves accelerated the development of the crop cycle, decreased plant growth, and increased the synthesis of phenolic compounds and anthocyanins in the outer scale leaves of the bulbs at harvest time, leading to 3-fold content increase compared with those conditioned at room temperature. Cold conditioning of "seed" cloves also altered the anthocyanin profile during bulb development and at harvest. Two new anthocyanins are reported for the first time in garlic. The high phenolics and anthocyanin contents in bulbs of plants generated from "seed" cloves conditioned at 5 °C for 5 weeks were preceded by overexpression of some putative genes of the phenolic metabolism [6-fold for phenylalanine ammonia lyase (PAL)] and anthocyanin synthesis [1-fold for UDP-sugar:flavonoid 3-O-glycosyltransferase (UFGT)] compared with those conditioned at room temperature.

  10. Engineering of Saccharomyces cerevisiae for production of resveratrol and its derivatives

    DEFF Research Database (Denmark)

    Li, Mingji

    were published in Applied and Environmental Microbiology (Jendresen et al., 2015). I then constructed the TAL pathway to resveratrol by expressing the two TAL genes in combination with 4-coumaryl-CoA ligase (4CL) from Arabidopsis thaliana and resveratrol synthase (VST) from Vitis vinifera in S...... carbon sources. I adopted rational metabolic engineering rational design strategies, synthetic biology techniques and system biology approaches to engineer and analyse yeast cell factories. There are two biosynthesis pathways of resveratrol, starting from tyrosine or phenylalanine, which in this thesis...... are defined as the TAL pathway and PAL pathway respectively. For the TAL pathway, I collaborated with Christian Bille Jendresen, Steen Gustav Stahlhut to screen fourteen diverse heterologous tyrosine ammonia lyases (TALs) for their activity in yeast and E. coli. I expressed the 14 TALs in S. cerevisiae...

  11. 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.

  12. 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 improved...

  13. Effect of Bacillus pumilus CCIBP-C5 on Musa-Pseudocercospora fijiensis interaction.

    Science.gov (United States)

    Cruz-Martín, Mileidy; Acosta-Suárez, Mayra; Mena, Eilyn; Roque, Berkis; Pichardo, Tatiana; Alvarado-Capó, Yelenys

    2018-02-01

    The effect of antifungal activity of culture filtrate (CF) of Bacillus pumilus strain CCIBP-C5, an isolate from a phyllosphere of banana ( Musa ) leaves, was determined on Pseudocercospora fijiensis challenged banana plants. The CF was shown to decrease the fungal biomass and induce changes in banana plant. In this sense, at 70 days post inoculation (dpi), a lower infection index as well as a decrease in fungal biomass after 6 dpi was obtained in treated plants with respect to control ones. At the same time, changes in the activities of several enzymes related to plant defense responses, such as phenylalanine ammonia lyase, chitinases, β-1,3-glucanases and peroxidases were observed. These results indicate that B. pumilus CCIBP-C5 has a potential role for biological control of P. fijiensis possibly due to the production of antifungal metabolites.

  14. 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.

  15. Use of some chemical inducers to improve wheat resistance to Puccinia striiformis f. Sp. Tritici

    Directory of Open Access Journals (Sweden)

    Al-Maaroof Emad

    2014-01-01

    Full Text Available The effect of DL-β-aminobutyric acid (BABA, benzothiadiazole (BTH, indoleacetic acid (IAA and salicylic acid (SA on induced systemic resistance was investigated in moderately susceptible and susceptible wheat genotypes Tamuz-2 and AL-8/70 against Puccinia striiformis f. sp. tritici. Resistance was characterized by reduced infection of yellow rust disease (Yrd. Changes in peroxidase, phenylalanine ammonia-lyase activities and in total phenolic compound content demonstrated that the resistance to Puccinia striiformis can be induced by BABA, BTH, IAA and SA in these two wheat genotypes. Further studies are needed before a practical method using many analogue compounds, such as potassium phosphate and biotic agent for Yrd resistance in wheat is developed.

  16. Solidago canadensis L essential oil vapor effectively inhibits Botrytis cinerea growth and preserves postharvest quality of strawberry as a food model system

    Directory of Open Access Journals (Sweden)

    Shumin Liu

    2016-08-01

    Full Text Available 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 (PAL, polyphenol oxidase (POD, or chitinase (CHI, 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.

  17. Broad host range ProUSER vectors enable fast characterization of inducible promoters and optimization of p-coumaric acid production in Pseudomonas putida KT2440

    DEFF Research Database (Denmark)

    Calero Valdayo, Patricia; Ingemann Jensen, Sheila; Nielsen, Alex Toftgaard

    2016-01-01

    Pseudomonas putida KT2440 has gained increasing interest as a host for the production of biochemicals. Because of the lack of a systematic characterization of inducible promoters in this strain, we generated ProUSER broad-host-expression plasmids that facilitate fast uracil-based cloning. A set...... of ProUSER-reporter vectors was further created to characterize different inducible promoters. The PrhaB and Pm promoters were orthogonal and showed titratable, high, and homogeneous expression. To optimize the production of p-coumaric acid, P. putida was engineered to prevent degradation of tyrosine...... and p-coumaric acid. Pm and PrhaB were used to control the expression of a tyrosine ammonia lyase or AroG* and TyrA* involved in tyrosine production, respectively. Pathway expression was optimized by modulating inductions, resulting in small-scale p-coumaric acid production of 1.2 mM, the highest...

  18. Plant defense induced in in vitro propagated banana (Musa paradisiaca) plantlets by Fusarium derived elicitors.

    Science.gov (United States)

    Patel, Miral; Kothari, I L; Mohan, J S S

    2004-07-01

    Perception of microbial signal molecules is part of the strategy evolved by plants to survive attacks by potential pathogens. To gain a more complete understanding of the early signaling events involved in these responses, we used fungal components of Fusarium under in vitro condition and checked the rise in signal molecule, salicylic acid (SA), and marker enzymes in defense reactions against the pathogen. SA level increased by 21 folds in elicitor treated plantlets as compared to that of control plantlets and there was marked increase in phenylalanine ammonia-lyase(PAL), peroxidase(POX), polyphenol oxidase(PPO) along with higher total phenolic content. Present results indicated that use of fungal components had successfully induced systemic resistance in in vitro cultured banana plantlets.

  19. Light and Fungal Elicitor Induce 3-Deoxy-d-arabino-Heptulosonate 7-Phosphate Synthase mRNA in Suspension Cultured Cells of Parsley (Petroselinum crispum L.) 1

    Science.gov (United States)

    Henstrand, John M.; McCue, Kent F.; Brink, Kent; Handa, Avtar K.; Herrmann, Klaus M.; Conn, Eric E.

    1992-01-01

    Light and fungal elicitor induce mRNA encoding 3-deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthase in suspension cultured cells of parsley (Petroselinum crispum L.). The kinetics and dose response of mRNA accumulation were similar for DAHP synthase and phenylalanine ammonia-lyase (PAL). Six micrograms of elicitor from Phytophthora megasperma f. glycinia gave a detectable induction within 1 hour. Induction of DAHP synthase and PAL mRNAs by light was transient, reaching maximal levels at 4 hours and returning to pretreatment levels after 24 hours. Our data suggest that either light or fungal elicitor transcriptionally activate DAHP synthase. A coordinate regulation for key enzymes in the synthesis of primary and secondary metabolites is indicated. ImagesFigure 1 PMID:16668708

  20. Regulation and Functional Expression of Cinnamate 4-Hydroxylase from Parsley

    Science.gov (United States)

    Koopmann, Edda; Logemann, Elke; Hahlbrock, Klaus

    1999-01-01

    A previously isolated parsley (Petroselinum crispum) cDNA with high sequence similarity to cinnamate 4-hydroxylase (C4H) cDNAs from several plant sources was expressed in yeast (Saccharomyces cerevisiae) containing a plant NADPH:cytochrome P450 oxidoreductase and verified as encoding a functional C4H (CYP73A10). Low genomic complexity and the occurrence of a single type of cDNA suggest the existence of only one C4H gene in parsley. The encoded mRNA and protein, in contrast to those of a functionally related NADPH:cytochrome P450 oxidoreductase, were strictly coregulated with phenylalanine ammonia-lyase mRNA and protein, respectively, as demonstrated by coinduction under various conditions and colocalization in situ in cross-sections from several different parsley tissues. These results support the hypothesis that the genes encoding the core reactions of phenylpropanoid metabolism form a tight regulatory unit. PMID:9880345

  1. Enhanced biocontrol activity of Rhodotorula mucilaginosa cultured in media containing chitosan against postharvest diseases in strawberries: possible mechanisms underlying the effect.

    Science.gov (United States)

    Zhang, Hongyin; Ge, Lingling; Chen, Keping; Zhao, Lina; Zhang, Xiaoyun

    2014-05-07

    The effect of Rhodotorula mucilaginosa cultured in media containing chitosan on its antogonistic activity against postharvest diseases of strawberries and the possible mechanisms involved are discussed. Two-dimensional gel electrophoresis were applied in the analysis of the proteins of R. mucilaginosa in response to chitosan. Compared with the application of R. mucilaginosa alone, the biocontrol efficacy of the yeast combined with 0.5% chitosan was enhanced greatly, with significant increase in chitinase activity of antagonistic yeast, polyphenoloxidase, peroxidase, phenylalanine ammonia lyase, chitinase and β-1,3-glucanase activity, and with an inhibition of lipid peroxidation of strawberries. The population of R. mucilaginosa harvested from NYDB amended with chitosan at 0.5% increased rapidly in strawberry wounds compared with those harvested from NYDB without chitosan. In the cellular proteome, several differentially expressed proteins were identified, most of which were related to basic metabolism.

  2. 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.

  3. 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.

  4. 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.

  5. Effect of temperature on enzymatic and physiological factors related to chilling injury in carambola fruit (Averrhoa carambola L.).

    Science.gov (United States)

    Pérez-Tello, G O; Silva-Espinoza, B A; Vargas-Arispuro, I; Briceño-Torres, B O; Martinez-Tellez, M A

    2001-10-05

    Three groups of carambola fruits (Averrhoa carambola L.) were stored at 2 and 10 degrees C (85-90% relative humidity). The major physicochemical, physiological, and enzymatic responses of fruit were measured in each group over a 30-day period: chilling injury index (CII), decay (%), intracuticular waxes, cuticle permeability, pulp firmness, weight loss, sucrose, fructose and glucose contents, ion electrolyte leakage in pulp (%), ethylene and carbon dioxide production rates, and the activities of peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) enzymes. CII values were statistically different at 2 and 10 degrees C, showing high significance with respect to sucrose content and weight loss (P < 0.05). Chilling injury included darkened ribs and skin desiccation. According to the CI symptom development, a possible relationship of POD and PPO activities was found at 2 degrees C. A significant sucrose content increase was observed at 10 degrees C. CI symptoms were associated with POD and PAL activities. Copyright 2001 Academic Press.

  6. A synbio approach for selection of highly expressed gene variants in Gram-positive bacteria

    DEFF Research Database (Denmark)

    Ferro, Roberto; Rennig, Maja; Hernández Rollán, Cristina

    2018-01-01

    with a long history in food fermentation. We have developed a synbio approach for increasing gene expression in two Gram-positive bacteria. First of all, the gene of interest was coupled to an antibiotic resistance gene to create a growth-based selection system. We then randomised the translation initiation...... region (TIR) preceding the gene of interest and selected clones that produced high protein titres, as judged by their ability to survive on high concentrations of antibiotic. Using this approach, we were able to significantly increase production of two industrially relevant proteins; sialidase in B....... subtilis and tyrosine ammonia lyase in L. lactis. Gram-positive bacteria are widely used to produce industrial enzymes. High titres are necessary to make the production economically feasible. The synbio approach presented here is a simple and inexpensive way to increase protein titres, which can be carried...

  7. A comparative transcriptome analysis of a wild purple potato and its red mutant provides insight into the mechanism of anthocyanin transformation.

    Directory of Open Access Journals (Sweden)

    Fang Liu

    Full Text Available In this study, a red mutant was obtained through in vitro regeneration of a wild purple potato. High-performance liquid chromatography and Mass spectrometry analysis revealed that pelargonidin-3-O-glucoside and petunidin-3-O-glucoside were main anthocyanins in the mutant and wild type tubers, respectively. In order to thoroughly understand the mechanism of anthocyanin transformation in two materials, a comparative transcriptome analysis of the mutant and wild type was carried out through high-throughput RNA sequencing, and 295 differentially expressed genes (DEGs were obtained. Real-time qRT-PCR validation of DEGs was consistent with the transcriptome date. The DEGs mainly influenced biological and metabolic pathways, including phenylpropanoid biosynthesis and translation, and biosynthesis of flavone and flavonol. In anthocyanin biosynthetic pathway, the analysis of structural genes expressions showed that three genes, one encoding phenylalanine ammonia-lyase, one encoding 4-coumarate-CoA ligase and one encoding flavonoid 3',5'-hydroxylasem were significantly down-regulated in the mutant; one gene encoding phenylalanine ammonia-lyase was significantly up-regulated. Moreover, the transcription factors, such as bZIP family, MYB family, LOB family, MADS family, zf-HD family and C2H2 family, were significantly regulated in anthocyanin transformation. Response proteins of hormone, such as gibberellin, abscisic acid and brassinosteroid, were also significantly regulated in anthocyanin transformation. The information contributes to discovering the candidate genes in anthocyanin transformation, which can serve as a comprehensive resource for molecular mechanism research of anthocyanin transformation in potatoes.

  8. Production of cinnamic and p-hydroxycinnamic acids in engineered microbes

    Directory of Open Access Journals (Sweden)

    Alejandra eVargas-Tah

    2015-08-01

    Full Text Available The aromatic compounds cinnamic and p-hydroxycinnamic acids 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 p-hydroxycinnamic acids 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 and L-tyrosine to cinnamic acid and p-hydroxycinnamic acid, respectively. Additional host modifications include the metabolic engineering to increase carbon flow from central metabolism to the L-phenylalanine or L-tyrosine 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.

  9. 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. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  10. Alleviation of Phytophthora capsici-induced oxidatıve stress by foliarly applied proline in Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Koç Esra

    2017-01-01

    Full Text Available Phytophthora capsici is a highly destructive pathogen of pepper. To examine whether proline modifies the levels of plant defense compounds produced in response to P. capsici-induced stress, pepper seedlings were infected with P. capsici-22 in the presence of proline (1 mM, 10 mM or in its absence. Proline was sprayed on the leaves of CM-334 and Kekova pepper cultivars prior to inoculation. CM-334 was more resistant to P. capsici-22, while the Kekova cultivar exhibited a sensitive reaction. P. capsici-22 increased the total phenolic compound and H2O2 levels, as well as phenylalanine ammonia-lyase, polyphenol oxidase and peroxidase activities in pepper seedlings. The application of exogenous proline further increased the activities of phenylalanine ammonia-lyase, polyphenol oxidase and peroxidase, as well as the total levels of phenolic compounds and the fresh and dry weights of the plants on the 5th and 7th days post treatment. After proline application, the highest catalase activity was found in both cultivars on the 5th day of the 10 mM proline + P. capsici application. On all days of the experiment, the applications caused a decrease in disease severity, necrosis length and H2O2 levels in both cultivars. In addition, proline decreased the colony growth of P. capsici and the number of zoospores. This finding indicates that enzymes and total phenolic compound levels protect the pepper seedlings against stress-related damage. Moreover, proline has the potential to directly scavenge free radicals and promote enzyme activity in pepper seedlings under P. capsici stress. These results suggest that foliar application of proline is an effective way to improve the stress tolerance of pepper to P. capsici.

  11. Effect of cut type on fresh-cut 'menina brasileira' zucchini quality Efeito do tipo de corte na qualidade de abobrinha 'Menina Brasileira' minimamente processada

    Directory of Open Access Journals (Sweden)

    Brígida Monteiro Vilas Boas

    2011-12-01

    Full Text Available Market sales of ready-to-use fresh fruit and vegetables have grown quickly in the recent years as a result of changes in consumer attitudes. The goal of this work was to evaluate the effect of two kinds of cuts on the physiological, physical, physical-chemical, chemical and biochemical traits of fresh-cut 'Menina Brasileira' zucchini stored in rigid polypropylene packages, with lids of the same material containing sliced and grated zucchini and stored at 5º C, for 15 days. The variables respiratory rate, pH, L* value, soluble pectin, PME and PG activity, was interactively affected by the cut type and storage time factors. The variables mass loss, phenylalanine ammonia-lyase activity and total pectin variable were only significantly affected by storage time factor. It can be concluded that sliced 'Menina Brasileira' zucchini shows a higher titratable acidity and soluble solids and a lower respiratory rate, pectin soluble and phenylalanine ammonia-lyase activity when compared with grated zucchini, contributing to the preservation of quality attributes.As vendas no mercado de frutas e hortaliças frescas prontas para o consumo têm crescido rapidamente nos últimos anos como resultado de mudanças nas atitudes dos consumidores. Neste trabalho objetivou-se avaliar o efeito de dois tipos de cortes nas características fisiológicas, físicas, químicas, físico-químicas e bioquímicas de abobrinha 'Menina Brasileira' minimamente processada, armazenada a 5º C em embalagens de polipropileno rígido, com tampas do mesmo material, contendo abobrinha fatiada e ralada, por 15 dias. As variáveis taxas respiratórias, pH, valor L*, pectina solúvel, atividade de PME e PG, foram interativamente afetadas pelos fatores tipo de corte e tempo de armazenamento. As variáveis perda de massa, atividade da fenilalanina amônia-liase e a pectina total foram afetadas significativamente apenas pelo fator tempo de armazenamento. Pode-se concluir que a abobrinha

  12. Transcriptional control of monolignol biosynthesis in Pinus taeda: factors affecting monolignol ratios and carbon allocation in phenylpropanoid metabolism

    Science.gov (United States)

    Anterola, Aldwin M.; Jeon, Jae-Heung; Davin, Laurence B.; Lewis, Norman G.

    2002-01-01

    Transcriptional profiling of the phenylpropanoid pathway in Pinus taeda cell suspension cultures was carried out using quantitative real time PCR analyses of all known genes involved in the biosynthesis of the two monolignols, p-coumaryl and coniferyl alcohols (lignin/lignan precursors). When the cells were transferred to a medium containing 8% sucrose and 20 mm potassium iodide, the monolignol/phenylpropanoid pathway was induced, and transcript levels for phenylalanine ammonia lyase, cinnamate 4-hydroxylase, p-coumarate 3-hydroxylase, 4-coumarate:CoA ligase, caffeoyl-CoA O-methyltransferase, cinnamoyl-CoA reductase, and cinnamyl alcohol dehydrogenase were coordinately up-regulated. Provision of increasing levels of exogenously supplied Phe to saturating levels (40 mm) to the induction medium resulted in further up-regulation of their transcript levels in the P. taeda cell cultures; this in turn was accompanied by considerable increases in both p-coumaryl and coniferyl alcohol formation and excretion. By contrast, transcript levels for both cinnamate 4-hydroxylase and p-coumarate 3-hydroxylase were only slightly up-regulated. These data, when considered together with metabolic profiling results and genetic manipulation of various plant species, reveal that carbon allocation to the pathway and its differential distribution into the two monolignols is controlled by Phe supply and differential modulation of cinnamate 4-hydroxylase and p-coumarate 3-hydroxylase activities, respectively. The coordinated up-regulation of phenylalanine ammonia lyase, 4-coumarate:CoA ligase, caffeoyl-CoA O-methyltransferase, cinnamoyl-CoA reductase and cinnamyl alcohol dehydrogenase in the presence of increasing concentrations of Phe also indicates that these steps are not truly rate-limiting, because they are modulated according to metabolic demand. Finally, the transcript profile of a putative acid/ester O-methyltransferase, proposed as an alternative catalyst for O-methylation leading

  13. Priming of seeds with methyl jasmonate induced resistance to hemi-biotroph Fusarium oxysporum f.sp. lycopersici in tomato via 12-oxo-phytodienoic acid, salicylic acid, and flavonol accumulation.

    Science.gov (United States)

    Król, P; Igielski, R; Pollmann, S; Kępczyńska, E

    2015-05-01

    Methyl jasmonate (MeJA) was tested by seed treatment for its ability to protect tomato seedlings against fusarium wilt caused by the soil-borne fungal pathogen Fusarium oxysporum f.sp. lycopersici. Isolated from Solanum lycopersicon L. seeds, cv. Beta fungus was identified as F. oxysporum f.sp. lycopersici Race 3 fungus by using phytopathological and molecular methods. MeJA applied at 0.01, 0.1 and 1 mM reduced spore germination and mycelial growth in vitro. Soaking of tomato seeds in MeJA solution at 0.1 mM for 1 h significantly enhanced the resistance level against the tested fungus in tomato seedlings 4 weeks after inoculation. The extracts from leaves of 15-day-old seedlings obtained from previously MeJA soaked seeds had the ability to inhibit in vitro spore germination of tested fungus. In these seedlings a significant increase in the levels phenolic compounds such as salicylic acid (SA), kaempferol and quercetin was observed. Up-regulation of phenylalanine ammonia-lyase (PAL5) and benzoic acid/salicylic acid carboxyl methyltransferase (BSMT) genes and down-regulation of the isochorysmate synthase (ICS) gene in response to exogenous MeJA application indicate that the phenylalanine ammonia-lyase (PAL), not the isochorismate (IC) pathway, is the primary route for SA production in tomato. Moreover, the increased accumulation of the flavonols quercetin and kaempferol appears closely related to the increase of PAL5, chalcone synthase (CHS) and flavonol synthase/flavanone 3-hydroxylase-like (FLS) genes. Elevated levels of salicylic acid in seedlings raised from MeJA-soaked seeds were simultaneously accompanied by a decrease of jasmonic acid, the precursor of MeJA, and an increase of 12-oxo-phytodienoic acid (OPDA), the precursor of jasmonic acid. The present results indicate that the priming of tomato seeds with 0.1mM MeJA before sowing enables the seedlings grown from these seeds to reduce the attack of the soil-borne fungal pathogen F. oxysporum f.sp. lycopersici

  14. Maize Lc transcription factor enhances biosynthesis of anthocyanins, distinct proanthocyanidins and phenylpropanoids in apple (Malus domestica Borkh.).

    Science.gov (United States)

    Li, Houhua; Flachowsky, Henryk; Fischer, Thilo C; Hanke, Magda-Viola; Forkmann, Gert; Treutter, Dieter; Schwab, Wilfried; Hoffmann, Thomas; Szankowski, Iris

    2007-10-01

    Flavonoids are a large family of polyphenolic compounds with manifold functions in plants. Present in a wide range of vegetables and fruits, flavonoids form an integral part of the human diet and confer multiple health benefits. Here, we report on metabolic engineering of the flavonoid biosynthetic pathways in apple (Malus domestica Borkh.) by overexpression of the maize (Zea mays L.) leaf colour (Lc) regulatory gene. The Lc gene was transferred into the M. domestica cultivar Holsteiner Cox via Agrobacterium tumefaciens-mediated transformation which resulted in enhanced anthocyanin accumulation in regenerated shoots. Five independent Lc lines were investigated for integration of Lc into the plant genome by Southern blot and PCR analyses. The Lc-transgenic lines contained one or two Lc gene copies and showed increased mRNA levels for phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), flavanone 3 beta-hydroxylase (FHT), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin reductases (LAR), anthocyanidin synthase (ANS) and anthocyanidin reductase (ANR). HPLC-DAD and LC-MS analyses revealed higher levels of the anthocyanin idaein (12-fold), the flavan 3-ol epicatechin (14-fold), and especially the isomeric catechin (41-fold), and some distinct dimeric proanthocyanidins (7 to 134-fold) in leaf tissues of Lc-transgenic lines. The levels of phenylpropanoids and their derivatives were only slightly increased. Thus, Lc overexpression in Malus domestica resulted in enhanced biosynthesis of specific flavonoid classes, which play important roles in both phytopathology and human health.

  15. 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.

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

    Science.gov (United States)

    Rawal, H C; Singh, N K; Sharma, T R

    2013-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Histidine protects against zinc and nickel toxicity in Caenorhabditis elegans.

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    John T Murphy

    2011-03-01

    Full Text Available Zinc is an essential trace element involved in a wide range of biological processes and human diseases. Zinc excess is deleterious, and animals require mechanisms to protect against zinc toxicity. To identify genes that modulate zinc tolerance, we performed a forward genetic screen for Caenorhabditis elegans mutants that were resistant to zinc toxicity. Here we demonstrate that mutations of the C. elegans histidine ammonia lyase (haly-1 gene promote zinc tolerance. C. elegans haly-1 encodes a protein that is homologous to vertebrate HAL, an enzyme that converts histidine to urocanic acid. haly-1 mutant animals displayed elevated levels of histidine, indicating that C. elegans HALY-1 protein is an enzyme involved in histidine catabolism. These results suggest the model that elevated histidine chelates zinc and thereby reduces zinc toxicity. Supporting this hypothesis, we demonstrated that dietary histidine promotes zinc tolerance. Nickel is another metal that binds histidine with high affinity. We demonstrated that haly-1 mutant animals are resistant to nickel toxicity and dietary histidine promotes nickel tolerance in wild-type animals. These studies identify a novel role for haly-1 and histidine in zinc metabolism and may be relevant for other animals.

  19. Nano-Calorimetry based point of care biosensor for metabolic disease management.

    Science.gov (United States)

    Kazura, Evan; Lubbers, Brad R; Dawson, Elliott; Phillips, John A; Baudenbacher, Franz

    2017-09-01

    Point of care (POC) diagnostics represents one of the fastest growing health care technology segments. Developments in microfabrication have led to the development of highly-sensitive nanocalorimeters ideal for directly measuring heat generated in POC biosensors. Here we present a novel nano-calorimeter-based biosensor design with differential sensing to eliminate common mode noise and capillary microfluidic channels for sample delivery to the thermoelectric sensor. The calorimeter has a resolution of 1.4 ± 0.2 nJ/(Hz) 1/2 utilizing a 27 junction bismuth/titanium thermopile, with a total Seebeck coefficient of 2160 μV/K. Sample is wicked to the calorimeter through a capillary channel making it suitable for monitoring blood obtained through a finger prick (performance in a model assay using catalase, achieving a threshold for hydrogen peroxide quantification of 50 μM. The potential for our device as a POC blood test for metabolic diseases is shown through the quantification of phenylalanine (Phe) in serum, an unmet necessary service in the management of Phenylketonuria (PKU). Pegylated phenylalanine ammonia-lyase (PEG-PAL) was utilized to react with Phe, but reliable detection was limited to <5 mM due to low enzymatic activity. The POC biosensor concept can be multiplexed and adapted to a large number of metabolic diseases utilizing different immobilized enzymes.

  20. 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. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, P.; Srirangarajan, A. N.; Padwal-Desai, S. R.; Ghanekar, A. S.; Shirsat, S. G.; Pendharkar, M. B.; Nair, P. M.; Nadkarni, G. B. [Biochemistry and Food Technology Division, Bhabha Atomic Research Centre, Bombay (India)

    1978-04-15

    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 Degree-Sign C belonged to Erwinia spp., while the rot caused below 10 Degree-Sign C was essentially due to Micrococcus spp. Irradiation followed by storage at cool temperatures (10-15 Degree-Sign C) offers an alternative method, comparable with conventional refrigerated (2-4 Degree-Sign 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. Garlic exerts allelopathic effects on pepper physiology in a hydroponic co-culture system

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    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.

  3. How polyamine synthesis inhibitors and cinnamic acid affect tropane alkaloid production.

    Science.gov (United States)

    Marconi, Patricia L; Alvarez, María A; Pitta-Alvarez, Sandra I

    2007-01-01

    Hairy roots of Brugmansia candida produce the tropane alkaloids scopolamine and hyoscyamine. In an attempt to divert the carbon flux from competing pathways and thus enhance productivity, the polyamine biosynthesis inhibitors cyclohexylamine (CHA) and methylglyoxal-bis-guanylhydrazone (MGBG) and the phenylalanine-ammonia-lyase inhibitor cinnamic acid were used. CHA decreased the specific productivity of both alkaloids but increased significantly the release of scopolamine (approx 500%) when it was added in the mid-exponential phase. However, when CHA was added for only 48 h during the exponential phase, the specific productivity of both alkaloids increased (approx 200%), favoring scopolamine. Treatment with MGBG was detrimental to growth but promoted release into the medium of both alkaloids. However, when it was added for 48 h during the exponential phase, MGBG increased the specific productivity (approx 200%) and release (250- 1800%) of both alkaloids. Cinnamic acid alone also favored release but not specific productivity. When a combination of CHA or MGBG with cinnamic acid was used, the results obtained were approximately the same as with each polyamine biosynthesis inhibitor alone, although to a lesser extent. Regarding root morphology, CHA inhibited growth of primary roots and ramification. However, it had a positive effect on elongation of lateral roots.

  4. Salicylic acid induces vanillin synthesis through the phospholipid signaling pathway in Capsicum chinense cell cultures.

    Science.gov (United States)

    Rodas-Junco, Beatriz A; Cab-Guillén, Yahaira; Muñoz-Sánchez, J Armando; Vázquez-Flota, Felipe; Monforte-González, Miriam; Hernández-Sotomayor, S M Teresa

    2013-10-01

    Signal transduction via phospholipids is mediated by phospholipases such as phospholipase C (PLC) and D (PLD), which catalyze hydrolysis of plasma membrane structural phospholipids. Phospholipid signaling is also involved in plant responses to phytohormones such as salicylic acid (SA). The relationships between phospholipid signaling, SA, and secondary metabolism are not fully understood. Using a Capsicum chinense cell suspension as a model, we evaluated whether phospholipid signaling modulates SA-induced vanillin production through the activation of phenylalanine ammonia lyase (PAL), a key enzyme in the biosynthetic pathway. Salicylic acid was found to elicit PAL activity and consequently vanillin production, which was diminished or reversed upon exposure to the phosphoinositide-phospholipase C (PI-PLC) signaling inhibitors neomycin and U73122. Exposure to the phosphatidic acid inhibitor 1-butanol altered PLD activity and prevented SA-induced vanillin production. Our results suggest that PLC and PLD-generated secondary messengers may be modulating SA-induced vanillin production through the activation of key biosynthetic pathway enzymes.

  5. Associations between variants of the HAL gene and milk production traits in Chinese Holstein cows.

    Science.gov (United States)

    Wang, Haifei; Jiang, Li; Wang, Wenwen; Zhang, Shengli; Yin, Zongjun; Zhang, Qin; Liu, Jian-Feng

    2014-11-25

    The histidine ammonia-lyse gene (HAL) encodes the histidine ammonia-lyase, which catalyzes the first reaction of histidine catabolism. In our previous genome-wide association study in Chinese Holstein cows to identify genetic variants affecting milk production traits, a SNP (rs41647754) located 357 bp upstream of HAL, was found to be significantly associated with milk yield and milk protein yield. In addition, the HAL gene resides within the reported QTLs for milk production traits. The aims of this study were to identify genetic variants in HAL and to test the association between these variants and milk production traits. Fifteen SNPs were identified within the regions under study of the HAL gene, including three coding mutations, seven intronic mutations, one promoter region mutation, and four 3'UTR mutations. Nine of these identified SNPs were chosen for subsequent genotyping and association analyses. Our results showed that five SNP markers (ss974768522, ss974768525, ss974768531, ss974768533 and ss974768534) were significantly associated with one or more milk production traits. Haplotype analysis showed that two haplotype blocks were significantly associated with milk yield and milk protein yield, providing additional support for the association between HAL variants and milk production traits in dairy cows (P HAL gene and milk production traits in Chinese Holstein cows, indicating the potential role of HAL variants in these traits. These identified SNPs may serve as genetic markers used in genomic selection schemes to accelerate the genetic gains of milk production traits in dairy cattle.

  6. Bidirectional reporter assay using HAL promoter and TOPFLASH improves specificity in high-throughput screening of Wnt inhibitors.

    Science.gov (United States)

    Yamaguchi, Kiyoshi; Zhu, Chi; Ohsugi, Tomoyuki; Yamaguchi, Yuko; Ikenoue, Tsuneo; Furukawa, Yoichi

    2017-12-01

    Constitutive activation of Wnt signaling plays an important role in colorectal and liver tumorigenesis. Cell-based assays using synthetic TCF/LEF (T-cell factor/lymphoid enhancer factor) reporters, as readouts of β-catenin/TCF-dependent transcriptional activity, have contributed greatly to the discovery of small molecules that modulate Wnt signaling. In the present study, we report a novel screening method, called a bidirectional dual reporter assay. Integrated transcriptome analysis identified a histidine ammonia-lyase gene (HAL) that was negatively regulated by β-catenin/TCF-dependent transcriptional activity. We leveraged a promoter region of the HAL gene as another transcriptional readout of Wnt signaling. Cells stably expressing both an optimized HAL reporter and the TCF/LEF reporter enabled bidirectional reporter activities in response to Wnt signaling. Increased HAL reporter activity and decreased TCF/LEF reporter activity were observed simultaneously in the cells when β-catenin/TCF7L2 was inhibited. Notably, this method could decrease the number of false positives observed when screening an inhibitor library compared with the conventional TCF/LEF assay. We found that Brefeldin A, a disruptor of the Golgi apparatus, inhibited the Wnt/β-catenin signaling pathway. The utility of our system could be expanded to examine other disease-associated pathways beyond the Wnt/β-catenin signaling pathway. © 2017 Wiley Periodicals, Inc.

  7. Chemical products induce resistance to Xanthomonas perforans in tomato

    Directory of Open Access Journals (Sweden)

    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.

  8. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

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

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    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Optimisation of trans-cinnamic acid and hydrocinnamyl alcohol production with recombinant Saccharomyces cerevisiae and identification of cinnamyl methyl ketone as a by-product.

    Science.gov (United States)

    Gottardi, Manuela; Grün, Peter; Bode, Helge B; Hoffmann, Thomas; Schwab, Wilfried; Oreb, Mislav; Boles, Eckhard

    2017-12-01

    Trans-cinnamic acid (tCA) and hydrocinnamyl alcohol (HcinOH) are valuable aromatic compounds with applications in the flavour, fragrance and cosmetic industry. They can be produced with recombinant yeasts from sugars via phenylalanine after expression of a phenylalanine ammonia lyase (PAL) and an aryl carboxylic acid reductase. Here, we show that in Saccharomyces cerevisiae a PAL enzyme from the bacterium Photorhabdus luminescens was superior to a previously used plant PAL enzyme for the production of tCA. Moreover, after expression of a UDP-glucose:cinnamate glucosyltransferase (FaGT2) from Fragaria x ananassa, tCA could be converted to cinnamoyl-D-glucose which is expected to be less toxic to the yeast cells. Production of tCA and HcinOH from glucose could be increased by eliminating feedback-regulated steps of aromatic amino acid biosynthesis and diminishing the decarboxylation step of the competing Ehrlich pathway. Finally, an unknown by-product resulting from further metabolisation of a carboligation product of cinnamaldehyde (cinALD) with activated acetaldehyde, mediated by pyruvate decarboxylases, could be identified as cinnamyl methyl ketone providing a new route for the biosynthesis of precursors, such as (2S,3R) 5-phenylpent-4-ene-2,3-diol, necessary for the chemical synthesis of specific biologically active drugs such as daunomycin. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. 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.

  13. Descriptive and hedonic analyses of low-Phe food formulations containing corn (Zea mays) seedling roots: toward development of a dietary supplement for individuals with phenylketonuria.

    Science.gov (United States)

    Cliff, Margaret A; Law, Jessica R; Lücker, Joost; Scaman, Christine H; Kermode, Allison R

    2016-01-15

    Seedling roots of anthocyanin-rich corn (Zea mays) cultivars contain high levels of phenylalanine ammonia lyase (PAL) activity. The development of a natural dietary supplement containing corn roots could provide the means to improve the restrictive diet of phenylketonuria (PKU) patients by increasing their tolerance to dietary phenylalanine (Phe). Therefore this research was undertaken to explore the sensory characteristics of roots of four corn cultivars as well as to develop and evaluate food products (cereal bar, beverage, jam-like spread) to which roots had been added. Sensory profiles of corn roots were investigated using ten trained judges. Roots of Japanese Striped corn seedlings were more bitter, pungent and astringent than those of white and yellow cultivars, while roots from the Blue Jade cultivar had a more pronounced earthy/mushroom aroma. Consumer research using 24 untrained panelists provided hedonic (degree-of-liking) assessments for products with and without roots (controls). The former had lower mean scores than the controls; however, the cereal bar had scores above 5 on the nine-point scale for all hedonic assessments compared with the other treated products. By evaluating low-Phe food products containing corn roots, this research ascertained that the root-containing low-Phe cereal bar was an acceptable 'natural' dietary supplement for PKU-affected individuals. © 2015 Her Majesty the Queen in Right of Canada. Journal of the Science of Food and Agriculture © 2015 Society of Chemical Industry.

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

    International Nuclear Information System (INIS)

    Gomes, Flavia B.; Moraes, Jair C.; Antunes, Cristiana; Santos, Custodio D. dos

    2008-01-01

    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)

  15. Light-induced Variation in Phenolic Compounds in Cabernet Sauvignon Grapes (Vitis vinifera L.) Involves Extensive Transcriptome Reprogramming of Biosynthetic Enzymes, Transcription Factors, and Phytohormonal Regulators.

    Science.gov (United States)

    Sun, Run-Ze; Cheng, Guo; Li, Qiang; He, Yan-Nan; Wang, Yu; Lan, Yi-Bin; Li, Si-Yu; Zhu, Yan-Rong; Song, Wen-Feng; Zhang, Xue; Cui, Xiao-Di; Chen, Wu; Wang, Jun

    2017-01-01

    Light environments have long been known to influence grape ( Vitis vinifera L.) berry development and biosynthesis of phenolic compounds, and ultimately affect wine quality. Here, the accumulation and compositional changes of hydroxycinnamic acids (HCAs) and flavonoids, as well as global gene expression were analyzed in Cabernet Sauvignon grape berries under sunlight exposure treatments at different phenological stages. Sunlight exposure did not consistently affect the accumulation of berry skin flavan-3-ol or anthocyanin among different seasons due to climatic variations, but increased HCA content significantly at véraison and harvest, and enhanced flavonol accumulation dramatically with its timing and severity degree trend. As in sunlight exposed berries, a highly significant correlation was observed between the expression of genes coding phenylalanine ammonia-lyase, 4-coumarate: CoA ligase, flavanone 3-hydroxylase and flavonol synthase family members and corresponding metabolite accumulation in the phenolic biosynthesis pathway, which may positively or negatively be regulated by MYB, bHLH, WRKY, AP2/EREBP, C2C2, NAC, and C2H2 transcription factors (TFs). Furthermore, some candidate genes required for auxin, ethylene and abscisic acid signal transductions were also identified which are probably involved in berry development and flavonoid biosynthesis in response to enhanced sunlight irradiation. Taken together, this study provides a valuable overview of the light-induced phenolic metabolism and transcriptome changes, especially the dynamic responses of TFs and signaling components of phytohormones, and contributes to the further understanding of sunlight-responsive phenolic biosynthesis regulation in grape berries.

  16. 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.

  17. Changes in energy metabolism accompanying pitting in blueberries stored at low temperature.

    Science.gov (United States)

    Zhou, Qian; Zhang, Chunlei; Cheng, Shunchang; Wei, Baodong; Liu, Xiuying; Ji, Shujuan

    2014-12-01

    Low-temperature storage and transport of blueberries is widely practiced in commercial blueberry production. In this research, the storage life of blueberries was extended at low temperature, but fruit stored for 30 d at 0°C pitted after 2d at room-temperature. Fruit cellular structure and physiological parameters accompanying pitting in blueberries were changed. The objective of this research was to characterise properties of energy metabolism accompanying pitting in blueberries during storage, including adenosine phosphates and mitochondrial enzymes involved in stress responses. Physiological and metabolic disorders, changes in cell ultrastructure, energy content and ATPase enzyme activity were observed in pitting blueberries. Energy shortages and increased activity of phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX) were observed in fruit kept at shelf life. The results suggested that sufficient available energy status and a stable enzymatic system in blueberries collectively contribute to improve chilling tolerance, thereby alleviating pitting and maintaining quality of blueberry fruit in long-term cold storage. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. 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.

  19. Accumulation of kaempferitrin and expression of phenyl-propanoid biosynthetic genes in kenaf (Hibiscus cannabinus).

    Science.gov (United States)

    Zhao, Shicheng; Li, Xiaohua; Cho, Dong Ha; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah; Park, Sang Un

    2014-10-23

    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.

  20. Involvement of plasma membrane peroxidases and oxylipin pathway in the recovery from phytoplasma disease in apple (Malus domestica).

    Science.gov (United States)

    Patui, Sonia; Bertolini, Alberto; Clincon, Luisa; Ermacora, Paolo; Braidot, Enrico; Vianello, Angelo; Zancani, Marco

    2013-06-01

    Apple trees (Malus domestica Borkh.) may be affected by apple proliferation (AP), caused by 'Candidatus Phytoplasma mali'. Some plants can spontaneously recover from the disease, which implies the disappearance of symptoms through a phenomenon known as recovery. In this article it is shown that NAD(P)H peroxidases of leaf plasma membrane-enriched fractions exhibited a higher activity in samples from both AP-diseased and recovered plants. In addition, an increase in endogenous SA was characteristic of the symptomatic plants, since its content increased in samples obtained from diseased apple trees. In agreement, phenylalanine ammonia lyase (PAL) activity, a key enzyme of the phenylpropanoid pathway, was increased too. Jasmonic acid (JA) increased only during recovery, in a phase subsequent to the pathological state, and in concomitance to a decline of salicylic acid (SA). Oxylipin pathway, responsible for JA synthesis, was not induced during the development of AP-disease, but it appeared to be stimulated when the recovery occurred. Accordingly, lipoxygenase (LOX) activity, detected in plasma membrane-enriched fractions, showed an increase in apple leaves obtained from recovered plants. This enhancement was paralleled by an increase of hydroperoxide lyase (HPL) activity, detected in leaf microsomes, albeit the latter enzyme was activated in either the disease or recovery conditions. Hence, a reciprocal antagonism between SA- and JA-pathways could be suggested as an effective mechanism by which apple plants react to phytoplasma invasions, thereby providing a suitable defense response leading to the establishment of the recovery phenomenon. Copyright © Physiologia Plantarum 2012.

  1. A multidisciplinary approach providing new insight into fruit flesh browning physiology in apple (Malus x domestica Borkh.).

    Science.gov (United States)

    Di Guardo, Mario; Tadiello, Alice; Farneti, Brian; Lorenz, Giorgia; Masuero, Domenico; Vrhovsek, Urska; Costa, Guglielmo; Velasco, Riccardo; Costa, Fabrizio

    2013-01-01

    In terms of the quality of minimally processed fruit, flesh browning is fundamentally important in the development of an aesthetically unpleasant appearance, with consequent off-flavours. The development of browning depends on the enzymatic action of the polyphenol oxidase (PPO). In the 'Golden Delicious' apple genome ten PPO genes were initially identified and located on three main chromosomes (2, 5 and 10). Of these genes, one element in particular, here called Md-PPO, located on chromosome 10, was further investigated and genetically mapped in two apple progenies ('Fuji x Pink Lady' and 'Golden Delicious x Braeburn'). Both linkage maps, made up of 481 and 608 markers respectively, were then employed to find QTL regions associated with fruit flesh browning, allowing the detection of 25 QTLs related to several browning parameters. These were distributed over six linkage groups with LOD values spanning from 3.08 to 4.99 and showed a rate of phenotypic variance from 26.1 to 38.6%. Anchoring of these intervals to the apple genome led to the identification of several genes involved in polyphenol synthesis and cell wall metabolism. Finally, the expression profile of two specific candidate genes, up and downstream of the polyphenolic pathway, namely phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO), provided insight into flesh browning physiology. Md-PPO was further analyzed and two haplotypes were characterised and associated with fruit flesh browning in apple.

  2. Melatonin treatment attenuates postharvest decay and maintains nutritional quality of strawberry fruits (Fragaria×anannasa cv. Selva) by enhancing GABA shunt activity.

    Science.gov (United States)

    Aghdam, Morteza Soleimani; Fard, Javad Rezapour

    2017-04-15

    Fresh strawberry fruits as perishable commodities have a short postharvest life and are prone to postharvest fungal decay. In this study, the impact of 0, 1, 10, 100 and 1000μmol/L melatonin on attenuating fungal decay and maintaining nutritional quality of strawberry fruits was investigated during storage at 4°C for 12days. Melatonin treatment at 100μmol/L triggered H 2 O 2 accumulation, which result from higher superoxide dismutase (SOD) activity, associated with lower catalase (CAT) and ascorbate peroxidase (APX) activities, leading to fruits with lower decay. Higher H 2 O 2 accumulation was concurrent with higher phenylalanine ammonia lyase (PAL) enzyme activity leading to higher total phenols and anthocyanins accumulation along with higher DPPH scavenging capacity. Also, strawberry fruits treated with melatonin exhibited higher γ-aminobutyric acid transaminase (GABA-T) enzyme activity which ensured sufficient ATP supplying leading to higher unsaturated/saturated fatty acids (unSFA/SFA) ratio. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Arthrobotrys oligospora-mediated biological control of diseases of tomato (Lycopersicon esculentum Mill.) caused by Meloidogyne incognita and Rhizoctonia solani.

    Science.gov (United States)

    Singh, U B; Sahu, A; Sahu, N; Singh, R K; Renu, S; Singh, D P; Manna, M C; Sarma, B K; Singh, H B; Singh, K P

    2013-01-01

    To study the biocontrol potential of nematode-trapping fungus Arthrobotrys oligospora in protecting tomato (Lycopersicon esculentum Mill.) against Meloidogyne incognita and Rhizoctonia solani under greenhouse and field conditions. Five isolates of the nematode-trapping fungus Arthrobotrys oligospora isolated from different parts of India were tested against Meloidogyne incognita and Rhizoctonia solani in tomato (Lycopersicon esculentum Mill.) plants grown under greenhouse and field conditions. Arthrobotrys oligospora-treated plants showed enhanced growth in terms of shoot and root length and biomass, chlorophyll and total phenolic content and high phenylalanine ammonia lyase activity in comparison with M. incognita- and R. solani-inoculated plants. Biochemical profiling when correlated with disease severity and intensity in A. oligospora-treated and untreated plants indicate that A. oligospora VNS-1 offered significant disease reduction in terms of number of root galls, seedling mortality, lesion length, disease index, better plant growth and fruit yield as compared to M. incognita- and R. solani-challenged plants. The result established that A. oligospora VNS-1 has the potential to provide bioprotection agents against M. incognita and R. solani. Arthrobotrys oligospora can be a better environment friendly option and can be incorporated in the integrated disease management module of crop protection. Application of A. oligospora not only helps in the control of nematodes but also increases plant growth and enhances nutritional value of tomato fruits. Thus, it proves to be an excellent biocontrol as well as plant growth promoting agent. © 2012 The Society for Applied Microbiology.

  4. Accumulation of catechins in tea in relation to accumulation of mRNA from genes involved in catechin biosynthesis.

    Science.gov (United States)

    Eungwanichayapant, P D; Popluechai, S

    2009-02-01

    Catechins are a group of polyphenols found in tea (Camellia sinensis var. sinensis) at high levels. They are beneficial for health. From the study on accumulation of catechins in shoots and mature leaves of a tea cultivar, Oolong No. 17, using high-performance liquid chromatography (HPLC), it was found that the amounts of most catechins in the shoots were higher than those in the mature leaves, with an exception of catechins gallate (CG) that was found in trace amounts in both the shoots and mature leaves. mRNA accumulation of genes involved in catechin synthesis was studied using reverse transcriptase-polymerase chain reaction (RT-PCR). The results showed that the mRNA accumulation of the genes were higher in the shoots than in the mature leaves. These genes included genes of phenylalanine ammonia-lyase 1 (PAL1; EC 4.3.1.5), chalcone synthase (CHS; EC 2.3.1.74), dihydroflavonol 4-reductase (DFR; EC 1.1.1.219), leucoanthocyanidin reductase (LCR; EC 1.17.1.3), and flavanone 3-hydroxylase (F3H; EC 1.14.11.9).

  5. Combined effects of Psoralens and ultraviolet-B on growth, pigmentation and biochemical parameters of Abelmoschus esculentus L.

    Science.gov (United States)

    Kumari, Rima; Singh, Suruchi; Agrawal, S B

    2009-05-01

    The effects of pre-treatment of Psoralens (furocoumarin compounds) and supplemental ultraviolet-B (sUV-B) were studied on plant growth, photosynthetic and non-photosynthetic pigments, protein, phenylalanine ammonia lyase (PAL) activity and antioxidative defense potential as well as their ultimate effects on biomass production in Abelmoschus esculentus L. (Okra) plants. Psoralens are capable of absorbing radiant energy and stimulating the pigmentation of human skin when photo-activated in presence of UV-A or UV-B making them beneficial in the treatment of vitilago. Pre-treatment of Psoralens against sUV-B (pUV-B), stimulates higher production of UV-B protective pigments (flavonoids and carotenoids) and helps in maintaining its biomass against UV-B stress. Antioxidative defense system in the test plant was activated by combined treatment of Psoralens and sUV-B as evidenced by the enhanced activity of enzymatic (ascorbate peroxidase-APX, superoxide dismutase-SOD, POX) and non-enzymatic (ascorbic acid and phenol) antioxidants. Individual treatments of Psoralens and sUV-B showed inhibitory effect on various morphological traits i.e. reduction in plant height, leaf area and ultimately on biomass production. Our results clearly indicated that adverse effect of sUV-B on biomass production was ameliorated by pre- treatment with Psoralens.

  6. Levels of potential bioactive compounds including carotenoids, vitamin C and phenolic compounds, and expression of their cognate biosynthetic genes vary significantly in different varieties of potato (Solanum tuberosum L.) grown under uniform cultural conditions.

    Science.gov (United States)

    Valcarcel, Jesus; Reilly, Kim; Gaffney, Michael; O'Brien, Nora M

    2016-02-01

    In addition to their high carbohydrate content, potatoes are also an important dietary source of vitamin C and bioactive secondary metabolites, including phenolic compounds and carotenoids, which have been suggested to play a role in human health. The expression of genes encoding key enzymes involved in the synthesis of these compounds was assessed by reverse transcription-quantitative polymerase chain reaction and compared to the accumulation of the corresponding product in seven potato varieties showing contrasting levels of metabolite accumulation. Strong positive correlations were found between phenolic content in the flesh of tubers and transcript levels of phenylalanine ammonia lyase (PAL) and chalcone synthase (CHS) genes. The expression of PAL and CHS was also related to that of AN1, a transcription factor involved in the synthesis of anthocyanins, suggesting that these genes are regulated in a coordinated manner. No clear relationship was found between transcript levels of phytoene synthase (PSY) or L-galactono-1,4-lactone dehydrogenase (GLDH) genes and total carotenoid or vitamin C accumulation, respectively. Data indicate that levels of total phenolic and flavonoid compounds in potato are controlled primarily by PAL and CHS gene expression. Transcript levels of PSY and GLDH did not control accumulation of carotenoids or vitamin C. © 2015 Society of Chemical Industry.

  7. [Effect of exogenous sucrose on growth and active ingredient content of licorice seedlings under salt stress conditions].

    Science.gov (United States)

    Liu, Fu-zhi; Yang, Jun

    2015-11-01

    Licorice seedlings were taken as experimental materials, an experiment was conducted to study the effects of exogenous sucrose on growth and active ingredient content of licorice seedlings under NaCl stress conditions. The results of this study showed that under salt stress conditions, after adding a certain concentration of exogenous sucrose, the licorice seedlings day of relative growth rate was increasing, and this stress can be a significant weakening effect, indicating that exogenous sucrose salt stress-relieving effect. The total flavonoids and phenylalanine ammonia lyase (PAL) activity were significantly increased, the exogenous sucrose can mitigated the seedling roots under salt stress, the licorice flavonoid content in the enhanced growth was largely due to the activity of PAL an increased, when the concentration of exogenous sucrose wae 10 mmol x L(-1), PAL activity reaching a maximum, when the concentration of exogenous sucrose was 15 mmol x L(-1), PAL activity turned into a downward trend, the results indicating that this mitigation has concentration effect. After applying different concentrations of exogenous sugar, the contents of liquiritin changes with the change of flavonoids content was similar. After applying different concentrations of exogenous sucrose, the content of licorice acid under salt stress was higher than the levels were not reached during salt stress, the impact of exogenous sucrose concentration gradient of licorice acid accumulation was not obvious.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. 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.

  10. Alterations in antioxidant metabolism in coffee leaves infected by Cercospora coffeicola

    Directory of Open Access Journals (Sweden)

    Camila Cristina Lage de Andrade

    2016-01-01

    Full Text Available ABSTRACT: Brown eye spot (BE caused by Cercospora coffeicola is the main disease of coffee crop. A variation in symptoms of BE has been reported in the field, raising suspicion of occurrence of new species. However, information about coffee- C. coffeicola interaction is still limited. This research aimed to determine the difference between antioxidant metabolism of coffee plants cultivar Mundo Novo inoculated with a strain isolated from a common BE lesion (CML 2984 and a strain isolated from a black BE lesion (CML 2985. The enzyme activity of peroxidase (POX, catalase (CAT, superoxide dismutase (SOD, ascorbate peroxidase (APX and phenylalanine ammonia lyase (PAL were determined. Activities of POX, APX, and PAL increased in plants inoculated with both strains compared to non-inoculated plants at 12 and 24 hours post inoculation (hpi. CAT activity increased in inoculated plants with black BE strain at 24 hpi and both strains at 48 hpi. The SOD activity only increased in inoculated plants with both strains at 48 hpi. These results show that an elevated antioxidant response was observed when the plants were challenged with both strains of C. coffeicola. Both strains produced lesions of the common type, suggesting that other factors lead to the development of black BE lesion type under field conditions and further investigation is needed.

  11. Up to date knowledge on different treatment strategies for phenylketonuria

    Science.gov (United States)

    Bélanger-Quintana, Amaya; Burlina, Alberto; Harding, Cary O.; Muntau, Ania C.

    2015-01-01

    Dietary management for phenylketonuria was established over half a century ago, and has rendered an immense success in the prevention of the severe mental retardation associated with the accumulation of phenylalanine. However, the strict low-phenylalanine diet has several shortcomings, not the least of which is the burden it imposes on the patients and their families consequently frequent dietary non-compliance. Imperfect neurological outcome of patients in comparison to non-PKU individuals and nutritional deficiencies associated to the PKU diet are other important reasons to seek alternative therapies. In the last decade there has been an impressive effort in the investigation of other ways to treat PKU that might improve the outcome and quality of life of these patients. These studies have lead to the commercialization of sapropterin dihydrochloride, but there are still many questions regarding which patients to challenge with sapropterin what is the best challenge protocol and what could be the implications of this treatment in the long-term. Current human trials of PEGylated phenylalanine ammonia lyase are underway, which might render an alternative to diet for those patients non-responsive to sapropterin dihydrochloride. Preclinical investigation of gene and cell therapies for PKU is ongoing. In this manuscript, we will review the current knowledge on novel pharmacologic approaches to the treatment of phenylketonuria. PMID:21967857

  12. Effects of sodium nitroprusside (SNP) pretreatment on UV-B stress tolerance in lettuce (Lactuca sativa L.) seedlings.

    Science.gov (United States)

    Esringu, Aslıhan; Aksakal, Ozkan; Tabay, Dilruba; Kara, Ayse Aydan

    2016-01-01

    Ultraviolet-B (UV-B) radiation is one of the most important abiotic stress factors that could influence plant growth, development, and productivity. Nitric oxide (NO) is an important plant growth regulator involved in a wide variety of physiological processes. In the present study, the possibility of enhancing UV-B stress tolerance of lettuce seedlings by the exogenous application of sodium nitroprusside (SNP) was investigated. UV-B radiation increased the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD) and total phenolic concentrations, antioxidant capacity, and expression of phenylalanine ammonia lyase (PAL) gene in seedlings, but the combination of SNP pretreatment and UV-B enhanced antioxidant enzyme activities, total phenolic concentrations, antioxidant capacity, and PAL gene expression even more. Moreover, UV-B radiation significantly inhibited chlorophylls, carotenoid, gibberellic acid (GA), and indole-3-acetic acid (IAA) contents and increased the contents of abscisic acid (ABA), salicylic acid (SA), malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide radical (O2•(-)) in lettuce seedlings. When SNP pretreatment was combined with the UV-B radiation, we observed alleviated chlorophylls, carotenoid, GA, and IAA inhibition and decreased content of ABA, SA, MDA, H2O2, and O2•(-) in comparison to non-pretreated stressed seedlings.

  13. Morphological and transcript changes in the biosynthesis of lignin in oil palm (Elaeis guineensis) during Ganoderma boninense infections in vitro.

    Science.gov (United States)

    Goh, Kar Mun; Dickinson, Matthew; Supramaniam, Christina V

    2018-03-01

    Lignification of the plant cell wall could serve as the first line of defense against pathogen attack, but the molecular mechanisms of virulence and disease between oil palm and Ganoderma boninense are poorly understood. This study presents the biochemical, histochemical, enzymology and gene expression evidences of enhanced lignin biosynthesis in young oil palm as a response to G. boninense (GBLS strain). Comparative studies with control (T1), wounded (T2) and infected (T3) oil palm plantlets showed significant accumulation of total lignin content and monolignol derivatives (syringaldehyde and vanillin). These derivatives were deposited on the epidermal cell wall of infected plants. Moreover, substantial differences were detected in the activities of enzyme and relative expressions of genes encoding phenylalanine ammonia lyase (EC 4.3.1.24), cinnamate 4-hydroxylase (EC 1.14.13.11), caffeic acid O-methyltransferase (EC 2.1.1.68) and cinnamyl alcohol dehydrogenase (CAD, EC 1.1.1.195). These enzymes are key intermediates dedicated to the biosynthesis of lignin monomers, the guaicyl (G), syringyl (S) and ρ-hydroxyphenyl (H) subunits. Results confirmed an early, biphasic and transient positive induction of all gene intermediates, except for CAD enzyme activities. These differences were visualized by anatomical and metabolic changes in the profile of lignin in the oil palm plantlets such as low G lignin, indicating a potential mechanism for enhanced susceptibility toward G. boninense infection. © 2017 Scandinavian Plant Physiology Society.

  14. Chitosan and grape secondary metabolites: A proteomics and metabolomics approach

    Directory of Open Access Journals (Sweden)

    Bavaresco Luigi

    2017-01-01

    Full Text Available Chitosan is a polysaccharide obtained by deacetylation of chitin, and it is involved in defence mechanisms of plants toward diseases. In the present work, V. vinifera L. cv. Ortrugo, grafted on 420A rootstock was grown in pot and treated, at veraison, by 0.03% chitosan solution at cluster level. Just before the treatment (T0 and 24 hours (T1, 48 hours (T2, 72 hours (T3 and 10 days (T4 later, the concentration of stilbenic compounds was detected, and at T1 proteomics and metabolomics analyses were done. Proteomics relies on the analysis of the complete set of proteins existing in a given substrate, while metabolomics relies on the analyses of the complete set of metabolites in a given substrate. The treatment improved the stilbene concentration over the control at T1. Proteomic analysis showed that superoxide dismutase (SOD and phenylalanine ammonia-lyase (PAL were overexpressed in the treated grapes. SOD is known to be an enzyme active against reactive oxygen species (ROS while PAL is a key enzyme in the phenylpropanoids pathway. Metabolomics analysis highlighted the positive role of the treatment in improving the triperpenoid concentration (betulin, erythrodiol, uvaol, oleanolate; these compounds are known to be effective against microbes, insects and fungi.

  15. A Multidisciplinary Approach Providing New Insight into Fruit Flesh Browning Physiology in Apple (Malus x domestica Borkh.)

    Science.gov (United States)

    Farneti, Brian; Lorenz, Giorgia; Masuero, Domenico; Vrhovsek, Urska; Costa, Guglielmo; Velasco, Riccardo; Costa, Fabrizio

    2013-01-01

    In terms of the quality of minimally processed fruit, flesh browning is fundamentally important in the development of an aesthetically unpleasant appearance, with consequent off-flavours. The development of browning depends on the enzymatic action of the polyphenol oxidase (PPO). In the ‘Golden Delicious’ apple genome ten PPO genes were initially identified and located on three main chromosomes (2, 5 and 10). Of these genes, one element in particular, here called Md-PPO, located on chromosome 10, was further investigated and genetically mapped in two apple progenies (‘Fuji x Pink Lady’ and ‘Golden Delicious x Braeburn’). Both linkage maps, made up of 481 and 608 markers respectively, were then employed to find QTL regions associated with fruit flesh browning, allowing the detection of 25 QTLs related to several browning parameters. These were distributed over six linkage groups with LOD values spanning from 3.08 to 4.99 and showed a rate of phenotypic variance from 26.1 to 38.6%. Anchoring of these intervals to the apple genome led to the identification of several genes involved in polyphenol synthesis and cell wall metabolism. Finally, the expression profile of two specific candidate genes, up and downstream of the polyphenolic pathway, namely phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO), provided insight into flesh browning physiology. Md-PPO was further analyzed and two haplotypes were characterised and associated with fruit flesh browning in apple. PMID:24205065

  16. 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.

  17. Cyanobacteria-mediated phenylpropanoids and phytohormones in rice (Oryza sativa) enhance plant growth and stress tolerance.

    Science.gov (United States)

    Singh, Dhananjaya P; Prabha, Ratna; Yandigeri, Mahesh S; Arora, Dilip K

    2011-11-01

    Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima, Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30 days. Qualitative analysis of the induced compounds using reverse phase HPLC and further confirmation with LC-MS/MS showed consistent accumulation of phenolic acids (gallic, gentisic, caffeic, chlorogenic and ferulic acids), flavonoids (rutin and quercetin) and phytohormones (indole acetic acid and indole butyric acid) in rice leaves. Plant growth promotion (shoot, root length and biomass) was positively correlated with total protein and chlorophyll content of leaves. Enzyme activity of peroxidase and phenylalanine ammonia lyase and total phenolic content was fairly high in rice leaves inoculated with O. acuta and P. boryanum after 30 days. Differential systemic accumulation of phenylpropanoids in plant leaves led us to conclude that cyanobacterial inoculation correlates positively with plant growth promotion and stress tolerance in rice. Furthermore, the study helped in deciphering possible mechanisms underlying plant growth promotion and stress tolerance in rice following cyanobacterial inoculation and indicated the less explored avenue of cyanobacterial colonization in stress tolerance against abiotic stress.

  18. Biochemical markers assisted screening of Fusarium wilt resistant Musa paradisiaca (L.) cv. puttabale micropropagated clones.

    Science.gov (United States)

    Venkatesh; Krishna, V; Kumar, K Girish; Pradeepa, K; Kumar, S R Santosh; Kumar, R Shashi

    2013-07-01

    An efficient protocol was standardized for screening of panama wilt resistant Musa paradisiaca cv. Puttabale clones, an endemic cultivar of Karnataka, India. The synergistic effect of 6-benzyleaminopurine (2 to 6 mg/L) and thidiazuron (0.1 to 0.5 mg/L) on MS medium provoked multiple shoot induction from the excised meristem. An average of 30.10 +/- 5.95 shoots was produced per propagule at 4 mg/L 6-benzyleaminopurine and 0.3 mg/L thidiazuron concentrations. Elongation of shoots observed on 5 mg/L BAP augmented medium with a mean length of 8.38 +/- 0.30 shoots per propagule. For screening of disease resistant clones, multiple shoot buds were mutated with 0.4% ethyl-methane-sulfonate and cultured on MS medium supplemented with Fusarium oxysporum f. sp. cubense (FOC) culture filtrate (5-15%). Two month old co-cultivated secondary hardened plants were used for screening of disease resistance against FOC by the determination of biochemical markers such as total phenol, phenylalanine ammonia lyase, oxidative enzymes like peroxidase, polyphenol oxidase, catalase and PR-proteins like chitinase, beta-1-3 glucanase activities. The mutated clones of M. paradisiaca cv. Puttabale cultured on FOC culture filtrate showed significant increase in the levels of biochemical markers as an indicative of acquiring disease resistant characteristics to FOC wilt.

  19. 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)

    Reuber, S.; Leitsch, J.; Krause, G.H.; Weissenböck, G.

    1993-01-01

    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

  20. Secondary metabolism and antioxidants are involved in environmental adaptation and stress tolerance in lettuce.

    Science.gov (United States)

    Oh, Myung-Min; Trick, Harold N; Rajashekar, C B

    2009-01-30

    Lettuce (Lactuca sativa) plants grown in a protective environment, similar to in vitro conditions, were acclimated in a growth chamber and subjected to water stress to examine the activation of genes involved in secondary metabolism and biosynthesis of antioxidants. The expression of phenylalanine ammonia-lyase (PAL), gamma-tocopherol methyl transferase (gamma-TMT) and l-galactose dehydrogenase (l-GalDH) genes involved in the biosynthesis of phenolic compounds, alpha-tocopherol and ascorbic acid, respectively, were determined during plant adaptation. These genes were activated in tender plants, grown under protective conditions, when exposed to normal growing conditions in a growth chamber. A large increase in transcript level for PAL, a key gene in the phenylpropanoid pathway leading to the biosynthesis of a wide array of phenolics and flavonoids, was observed within 1h of exposure of tender plants to normal growing conditions. Plant growth, especially the roots, was retarded in tender plants when exposed to normal growing conditions. Furthermore, exposure of both protected and unprotected plants to water stress resulted in the activation of PAL. PAL inhibition by 2-aminoindan-2-phosphonic acid (AIP) rendered these plants more sensitive to chilling and heat shock treatments. These results suggest that activation of secondary metabolism as well as the antioxidative metabolism is an integral part of plant adaptation to normal growing conditions in lettuce plants.

  1. Production of soybean isoflavone genistein in non-legume plants via genetically modified secondary metabolism pathway.

    Science.gov (United States)

    Liu, Rongrong; Hu, Yuanlei; Li, Jialin; Lin, Zhongping

    2007-01-01

    Genetic modification of secondary metabolic pathways to produce desirable natural products is an attractive approach in plant biotechnology. In our study, we attempted to produce a typical soybean isoflavone genistein, a well-known health-promoting metabolite, in non-legume plants via genetic engineering. Both overexpression and antisense suppression strategies were used to manipulate the expression of several genes encoding key enzymes in the flavonoids/isoflavonoids pathway in transgenic tobacco, lettuce, and petunia. Introducing soybean isoflavone synthase (IFS) into these plants, which naturally do not produce isoflavonoids due to a lack of this leguminous enzyme, resulted in genistein biosynthesis in tobacco petals, petunia leaves and petals, and lettuce leaves. In tobacco, when flavanone 3-hydroxylase (F3H) expression was suppressed by its antisense gene while soybean IFS was overexpressed at the same time, genistein yield increased prominently. In addition, overexpression of phenylalanine ammonia-lyase (PAL) also led to an enhanced genistein production in tobacco petals and lettuce leaves in the presence of IFS than in the plants that overexpressed only IFS.

  2. Positive effects of temperature and growth conditions on enzymatic and antioxidant status in lettuce plants.

    Science.gov (United States)

    Boo, Hee-Ock; Heo, Buk-Gu; Gorinstein, Shela; Chon, Sang-Uk

    2011-10-01

    The contents of two bioactive compounds (polyphenols and flavonoids) and their antioxidant and enzyme activities were determined in the leaves of six lettuce (Latuca sativa L.) cultivars subjected to 4 different day/night temperatures for 6 weeks. The total polyphenol and anthocyanin contents and the corresponding antioxidant activities were the highest at 13/10°C and 20/13°C, followed by 25/20°C and 30/25°C. The enzymatic activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) were also the highest at low day/night temperatures, but the peroxidase (POD) activity was decreased at low day/night temperatures and increased at high day/night temperatures. The most significant positive correlation existed between anthocyanin content and PPO activity, total polyphenols and their antioxidant activities. The results showed that at relatively low temperatures, lettuce plants have a high antioxidant and enzymatic status. These results provide additional information for the lettuce growers. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  3. 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. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. A synbio approach for selection of highly expressed gene variants in Gram-positive bacteria.

    Science.gov (United States)

    Ferro, Roberto; Rennig, Maja; Hernández-Rollán, Cristina; Daley, Daniel O; Nørholm, Morten H H

    2018-03-08

    The market for recombinant proteins is on the rise, and Gram-positive strains are widely exploited for this purpose. Bacillus subtilis is a profitable host for protein production thanks to its ability to secrete large amounts of proteins, and Lactococcus lactis is an attractive production organism with a long history in food fermentation. We have developed a synbio approach for increasing gene expression in two Gram-positive bacteria. First of all, the gene of interest was coupled to an antibiotic resistance gene to create a growth-based selection system. We then randomised the translation initiation region (TIR) preceding the gene of interest and selected clones that produced high protein titres, as judged by their ability to survive on high concentrations of antibiotic. Using this approach, we were able to significantly increase production of two industrially relevant proteins; sialidase in B. subtilis and tyrosine ammonia lyase in L. lactis. Gram-positive bacteria are widely used to produce industrial enzymes. High titres are necessary to make the production economically feasible. The synbio approach presented here is a simple and inexpensive way to increase protein titres, which can be carried out in any laboratory within a few days. It could also be implemented as a tool for applications beyond TIR libraries, such as screening of synthetic, homologous or domain-shuffled genes.

  5. 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)

    Sharma, R.; Kant, A.; Kaushal, R.P.

    2004-01-01

    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 [it

  6. Biocontrol agent Bacillus amyloliquefaciens LJ02 induces systemic resistance against cucurbits powdery mildew.

    Science.gov (United States)

    Li, Yunlong; Gu, Yilin; Li, Juan; Xu, Mingzhu; Wei, Qing; Wang, Yuanhong

    2015-01-01

    Powdery mildew is a fungal disease found in a wide range of plants and can significantly reduce crop yields. Bacterial strain LJ02 is a biocontrol agent (BCA) isolated from a greenhouse in Tianjin, China. In combination of morphological, physiological, biochemical and phylogenetic analyses, strain LJ02 was classified as a new member of Bacillus amyloliquefaciens. Greenhouse trials showed that LJ02 fermentation broth (LJ02FB) can effectively diminish the occurrence of cucurbits powdery mildew. When treated with LJ02FB, cucumber seedlings produced significantly elevated production of superoxide dismutase, peroxidase, polyphenol oxidase and phenylalanine ammonia lyase as compared to that of the control. We further confirmed that the production of free salicylic acid (SA) and expression of one pathogenesis-related (PR) gene PR-1 in cucumber leaves were markedly elevated after treating with LJ02FB, suggesting that SA-mediated defense response was stimulated. Moreover, LJ02FB-treated cucumber leaves could secrete resistance-related substances into rhizosphere that inhibit the germination of fungi spores and the growth of pathogens. Finally, we separated bacterium and its fermented substances to test their respective effects and found that both components have SA-inducing activity and bacterium plays major roles. Altogether, we identified a BCA against powdery mildew and its mode of action by inducing systemic resistance such as SA signaling pathway.

  7. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. 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.

  9. Boron alleviates the aluminum toxicity in trifoliate orange by regulating antioxidant defense system and reducing root cell injury.

    Science.gov (United States)

    Riaz, Muhammad; Yan, Lei; Wu, Xiuwen; Hussain, Saddam; Aziz, Omar; Wang, Yuhan; Imran, Muhammad; Jiang, Cuncang

    2018-02-15

    Aluminium (Al) toxicity is the most important soil constraint for plant growth and development in acid soils (pH Boron (B) is an essential micronutrient for the growth and development of higher plants. The results of previous studies propose that B might ameliorate Al toxicity; however, none of the studies have been conducted on trifoliate orange to study this effect. Thus, a study was carried out in hydroponics comprising of two different Al concentrations, 0 and 400 μM. For every concentration, two B treatments (0 and 10 μM as H 3 BO 3 ) were applied to investigate the B-induced alleviation of Al toxicity and exploring the underneath mechanisms. The results revealed that Al toxicity under B deficiency severely hampered the root growth and physiology of plant, caused oxidative stress and membrane damage, leading to severe root injury and damage. However, application of B under Al toxicity improved the root elongation and photosynthesis, while reduced Al uptake and mobilization into plant parts. Moreover, B supply regulated the activities of antioxidant enzymes, proline, secondary metabolites (phenylalanine ammonia lyase and polyphenol oxidase) contents, and stabilized integrity of proteins. Our study results imply that B supply promoted root growth as well as defense system by reducing reactive oxygen species (ROS) and Al concentrations in plant parts thus B induced alleviation of Al toxicity; a fact that might be significant for higher productivity of agricultural plants grown in acidic conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. UV light selectively coinduces supply pathways from primary metabolism and flavonoid secondary product formation in parsley

    Science.gov (United States)

    Logemann, Elke; Tavernaro, Annette; Schulz, Wolfgang; Somssich, Imre E.; Hahlbrock, Klaus

    2000-01-01

    The UV light-induced synthesis of UV-protective flavonoids diverts substantial amounts of substrates from primary metabolism into secondary product formation and thus causes major perturbations of the cellular homeostasis. Results from this study show that the mRNAs encoding representative enzymes from various supply pathways are coinduced in UV-irradiated parsley cells (Petroselinum crispum) with two mRNAs of flavonoid glycoside biosynthesis, encoding phenylalanine ammonia-lyase and chalcone synthase. Strong induction was observed for mRNAs encoding glucose 6-phosphate dehydrogenase (carbohydrate metabolism, providing substrates for the shikimate pathway), 3-deoxyarabinoheptulosonate 7-phosphate synthase (shikimate pathway, yielding phenylalanine), and acyl-CoA oxidase (fatty acid degradation, yielding acetyl-CoA), and moderate induction for an mRNA encoding S-adenosyl-homocysteine hydrolase (activated methyl cycle, yielding S-adenosyl-methionine for B-ring methylation). Ten arbitrarily selected mRNAs representing various unrelated metabolic activities remained unaffected. Comparative analysis of acyl-CoA oxidase and chalcone synthase with respect to mRNA expression modes and gene promoter structure and function revealed close similarities. These results indicate a fine-tuned regulatory network integrating those functionally related pathways of primary and secondary metabolism that are specifically required for protective adaptation to UV irradiation. Although the response of parsley cells to UV light is considerably broader than previously assumed, it contrasts greatly with the extensive metabolic reprogramming observed previously in elicitor-treated or fungus-infected cells. PMID:10677554

  11. A Benzothiadiazole Primes Parsley Cells for Augmented Elicitation of Defense Responses

    Science.gov (United States)

    Katz, Vera A.; Thulke, Oliver U.; Conrath, Uwe

    1998-01-01

    Systemic acquired resistance is an important component of the disease-resistance arsenal of plants, and is associated with an enhanced potency for activating local defense responses upon pathogen attack. Here we demonstrate that pretreatment with benzothiadiazole (BTH), a synthetic activator of acquired resistance in plants, augmented the sensitivity for low-dose elicitation of coumarin phytoalexin secretion by cultured parsley (Petroselinum crispum L.) cells. Enhanced coumarin secretion was associated with potentiated activation of genes encoding Phe ammonia-lyase (PAL). The augmentation of PAL gene induction was proportional to the length of pretreatment with BTH, indicating time-dependent priming of the cells. In contrast to the PAL genes, those for anionic peroxidase were directly induced by BTH in the absence of elicitor, thus confirming a dual role for BTH in the activation of plant defenses. Strikingly, the ability of various chemicals to enhance plant disease resistance correlated with their capability to potentiate parsley PAL gene elicitation, emphasizing an important role for defense response potentiation in acquired plant disease resistance. PMID:9701589

  12. Early phenylpropanoid biosynthetic steps in Cannabis sativa: link between genes and metabolites.

    Science.gov (United States)

    Docimo, Teresa; Consonni, Roberto; Coraggio, Immacolata; Mattana, Monica

    2013-06-28

    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.

  13. 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.

  14. Thyme oil vapour and modified atmosphere packaging reduce anthracnose incidence and maintain fruit quality in avocado.

    Science.gov (United States)

    Sellamuthu, Periyar Selvam; Mafune, Mpho; Sivakumar, Dharini; Soundy, Puffy

    2013-09-01

    Postharvest application of prochloraz fungicide is commercially practiced to control anthracnose, a postharvest disease in avocado. Increasing consumer concern regarding food safety and demand for organically produced fruits make it necessary to search for natural environmentally friendly alternative products and processes for the fruit industry. A combination of modified atmosphere packaging (MAP; ∼8% CO₂, 2% O₂) plus thyme oil (TO) was evaluated on the incidence and severity of anthracnose, physiological disorders (grey pulp, vascular browning), fruit quality parameters (L*, h°, firmness, weight loss) and sensory parameters (taste, texture, flavour and overall acceptance), phenylalanine ammonia-lyase (PAL) enzyme activity, total phenolic compounds, flavonoid contents and antioxidant activity in avocados ('Fuerte' and 'Hass' cultivars) held at 10 °C cold storage for 18 days and thereafter, ripened at 25 °C for 5-10 days. Stand-alone MAP, commercial treatment (prochloraz 0.05%) and untreated (control) fruit were included for comparison. MAP + TO treatment significantly (P anthracnose, grey pulp, vascular browning, weight loss and loss of fruit firmness, and showed acceptable taste, flavour, texture and higher overall acceptance, increased PAL activity, total phenolic compounds, flavonoid contents and antioxidant activity, after ripening at 25 °C followed by cold storage at 10 °C. This investigation recommends MAP + TO combination treatment as a suitable alternative to the currently adopted prochloraz application. © 2013 Society of Chemical Industry.

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

    International Nuclear Information System (INIS)

    Cao, Z.; Dong, C.; Zhang, X.

    2014-01-01

    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)

  16. 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.

  17. 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

  18. Activities of some enzymes of lignin formation in reaction wood of Thuja orientalis, Metasequoia glyptostroboides and Robinia pseudoacacia.

    Science.gov (United States)

    Kutsuki, H; Higuchi, T

    1981-07-01

    The activities of the following five enzymes which are involved in the formation of lignin have been compared in reaction wood and in opposite wood: phenylalanine ammonia lyase (EC 4.3.1.5), caffeate 3-O-methyltransferase (EC 2.1.1.-), p-hydroxycinnamate: CoA ligase (EC 6.2.1.12), cinnamyl alcohol dehydrogenase (EC 1.1.1.-) and peroxidase (EC 1.11.1.7). The activities of the four first-named enzymes in the compression wood of Thuja orientalis L. and Metasequoia glyptostroboides Hu et Cheng were 2.8±1.4-fold and 2.6±1.5-fold higher than those in opposite wood, respectively, whereas peroxidase had the same level of activity in either type of wood. On the other hand, no differences were observed in the activities of the five enzymes between tension and opposite woods of Robinia pseudoacacia L. These findings are well in accord with the chemical structure of lignin in the compression and tension woods of the three species studied: high content of lignin rich in condensed units in compression wood, and little difference in lignin between tension and opposite woods.

  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.

  20. Seed Priming with Melatonin Effects on Seed Germination and Seedling Growth in Maize under Salinity Stress

    International Nuclear Information System (INIS)

    Jiang, X.; Li, H.; Song, X.

    2016-01-01

    The effects on seed germination and seedling growth in maize under salinity stress by seed priming with melatonin were investigated. Seeds of maize cultivar Nonghua101 were soaked in 0.4, 0.8 and 1.6 mM aerated solution of melatonin for 24 h, and primed seeds were germinated under the condition of 150 mM NaCl with paper media. The results showed seed priming with 0.8 mM melatonin was the best performance of all the treatments to seed germination and seedling growth in maize under salinity stress. Then primed with 0.8 mM melatonin or water for 24 h and unprimed seeds were germination under the condition of 150 mM NaCl with sand media. The results showed seed priming with 0.8 mM melatonin significantly improved germination energy, germination percentage, seedling vigor index, shoot and root lengths, seedling fresh and dry weights, K/sup +/ content, relative water content, proline and total phenolic contents, superoxide dismutase, catalase and phenylalanin ammonia lyase activities; and significantly decreased mean emergence time, Na/sup +/ content, electrolyte leakage and malondialdehyde content compared with untreated seeds under salinity stress. These results suggest that seed priming with melatonin alleviates the salinity damage to maize and seed priming with melatonin may be an important alternative approach to decrease the impact of salinity stress in maize. (author)

  1. 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

    2016-05-25

    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.

  2. Biochemical analysis of induced resistance in chickpea against broomrape (Orobanche foetida by rhizobia inoculation

    Directory of Open Access Journals (Sweden)

    Yassine MABROUK

    2016-05-01

    Full Text Available This study examined the capacity of Rhizobium sp. strain PchAZM to reduce parasitism of chickpea by Orobanche foetida under greenhouse conditions, and assessed the relative impact of rhizobia on the expression of chickpea defense response against broomrape. Growth chamber experiments using Petri dishes revealed that rhizobia infection on chickpea roots reduced broomrape seed germination, and restricted the broomrape attachment to host roots while retarding tubercle formation and development by the parasite. In pot experiments, chickpea roots inoculated with rhizobia reduced the total number of broomrape by up to 90%. Broomrape necrosis was observed both before and after parasite attachment to inoculated chickpea roots in Petri dishes and pot experiments. Reduction in infection was accompanied by enhanced levels of the defence-related enzymes phenylalanine ammonia lyase (PAL and peroxidase (POX. Increased levels of phenolics were recorded in the roots of rhizobia-inoculated plants grown in the presence of broomrape. The results suggest that rhizobia could be used for protection of chickpea against O. foetida.

  3. Phenotypical and biochemical characterisation of resistance for parasitic weed (Orobanche foetida Poir.) in radiation-mutagenised mutants of chickpea.

    Science.gov (United States)

    Brahmi, Ines; Mabrouk, Yassine; Brun, Guillaume; Delavault, Philippe; Belhadj, Omrane; Simier, Philippe

    2016-12-01

    Some radiation-mutagenised chickpea mutants potentially resistant to the broomrape, Orobanche foetida Poir., were selected through field trials. The objectives of this work were to confirm resistance under artificial infestation, in pots and mini-rhizotron systems, and to determine the developmental stages of broomrape affected by resistance and the relevant resistance mechanisms induced by radiation mutagenesis. Among 30 mutants tested for resistance to O. foetida, five shared strong resistance in both pot experiments and mini-rhizotron systems. Resistance was not complete, but the few individuals that escaped resistance displayed high disorders of shoot development. Results demonstrated a 2-3-fold decrease in stimulatory activity of root exudates towards broomrape seed germination in resistant mutants in comparison with non-irradiated control plants and susceptible mutants. Resistance was associated with an induction of broomrape necrosis early during infection. When infested, most of the resistant mutants shared enhanced levels of soluble phenolic contents, phenylalanine ammonia lyase activity, guaiacol peroxidase activity and polyphenol oxidase activity, in addition to glutathione and notably ascorbate peroxidase gene expression in roots. Results confirmed enhanced resistance in chickpea radiation-mutagenised mutants, and demonstrated that resistance is based on alteration of root exudation, presumed cell-wall reinforcement and change in root oxidative status in response to infection. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  4. The effect of ultraviolet treatment on enzymatic activity and total phenolic content of minimally processed potato slices.

    Science.gov (United States)

    Teoh, Li Shing; Lasekan, Ola; Adzahan, Noranizan Mohd; Hashim, Norhashila

    2016-07-01

    In this work, potato slices were exposed to different doses of UV-C irradiation (i.e. 2.28, 6.84, 11.41, and 13.68 kJ m -2 ) with or without pretreatment [i.e. ascorbic acid and calcium chloride (AACCl) dip] and stored at 4 ± 1 °C. Changes in enzymatic activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase (PAL), as well as total phenolic content (TPC) were investigated after 0, 3, 7 and 10 days of storage. Results showed that untreated and UV-C treated potato slices at 13.68 kJ m -2 dosage level showed significantly higher PPO, POD and PAL activities. Conversely, untreated potato slices showed the lowest TPC during storage period. Potato slices subjected to AACCl dip plus UV-C at 6.84 kJ m -2 produced lower PPO, POD and PAL activities, as well as maintained a high TPC during storage.

  5. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Maxwell, C.A.; Phillips, D.A.

    1990-01-01

    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- 14 C]-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 14 C. In the presence of AOPP, 14 C 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

  7. Biofortification (Se: Does it increase the content of phenolic compounds in virgin olive oil (VOO?

    Directory of Open Access Journals (Sweden)

    Roberto D'Amato

    Full Text Available Extra-Virgin Olive Oil (EVOO is a fundamental component of the Mediterranean diet and it may contain several anti-oxidant substances, such as phenols. Previous research has shown that this food may be enriched in phenols by spraying a sodium-selenate solution (100 mg L-1 Se onto the crop canopy before flowering. The aim of this research was to evaluate the effect of this Se-fertilization before flowering (cv. Leccino on the phenolic profile of EVOOs, and test to what extent such effects depend on the weather pattern, as observed in two contrasting experimental seasons (2013 and 2014. Results showed that Se-fertilisation enriched EVOOs both in selenium (up to 120 μg kg-1 and in phenols (up to 401 mg kg-1. This latter enrichment was related to an increase in PAL (L-Phenylalanine Ammonia-Lyase activities and it was largely independent on the climatic pattern. Considering the phenolic profile, oleacein, ligustroside, aglycone and oleocanthal were the most affected compounds and were increased by 57, 50 and 32%, respectively. All these compounds, especially oleacein, have been shown to exert a relevant anti-oxidant activity, contributing both to the shelf-life of EVOOs and to positive effects on human health. It is suggested that Se-fertilisation of olive trees before flowering may be an interesting practice, particularly with poor cultivars and cold and rainy weather patterns, which would normally lead to the production of EVOOs with unfavourable phenolic profile.

  8. Biofortification (Se): Does it increase the content of phenolic compounds in virgin olive oil (VOO)?

    Science.gov (United States)

    D’Amato, Roberto; Proietti, Primo; Onofri, Andrea; Regni, Luca; Esposto, Sonia; Servili, Maurizio; Businelli, Daniela; Selvaggini, Roberto

    2017-01-01

    Extra-Virgin Olive Oil (EVOO) is a fundamental component of the Mediterranean diet and it may contain several anti-oxidant substances, such as phenols. Previous research has shown that this food may be enriched in phenols by spraying a sodium-selenate solution (100 mg L-1 Se) onto the crop canopy before flowering. The aim of this research was to evaluate the effect of this Se-fertilization before flowering (cv. Leccino) on the phenolic profile of EVOOs, and test to what extent such effects depend on the weather pattern, as observed in two contrasting experimental seasons (2013 and 2014). Results showed that Se-fertilisation enriched EVOOs both in selenium (up to 120 μg kg-1) and in phenols (up to 401 mg kg-1). This latter enrichment was related to an increase in PAL (L-Phenylalanine Ammonia-Lyase) activities and it was largely independent on the climatic pattern. Considering the phenolic profile, oleacein, ligustroside, aglycone and oleocanthal were the most affected compounds and were increased by 57, 50 and 32%, respectively. All these compounds, especially oleacein, have been shown to exert a relevant anti-oxidant activity, contributing both to the shelf-life of EVOOs and to positive effects on human health. It is suggested that Se-fertilisation of olive trees before flowering may be an interesting practice, particularly with poor cultivars and cold and rainy weather patterns, which would normally lead to the production of EVOOs with unfavourable phenolic profile. PMID:28448631

  9. Antiviral activity of the exopolysaccharide produced by Serratia sp. strain Gsm01 against Cucumber mosaic virus.

    Science.gov (United States)

    Ipper, Nagesh S; Cho, Saeyoull; Lee, Seon Hwa; Cho, Jun Mo; Hur, Jang Hyun; Lim, Chun Keun

    2008-01-01

    The potential of the exopolysaccharide (EPS) from a Serratia sp. strain Gsm01 as an antiviral agent against a yellow strain of Cucumber mosaic virus (CMV-Y) was evaluated in tobacco plants (Nicotiana tabacum cv. Xanthi-nc). The spray treatment of plants using an EPS preparation, 72 before CMV-Y inoculation, protected them against symptom appearance. Fifteen days after challenge inoculation with CMVY, 33.33% of plants showed mosaic symptoms in EPS-treated plants compared with 100% in the control plants. The EPS-treated plants, which showed mosaic symptoms, appeared three days later than the controls. The enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR) analyses of the leaves of the protected plants revealed that the EPS treatment affected virus accumulation in those plants. Analysis of phenylalanine ammonia lyase, peroxidase, and phenols in protected plants revealed enhanced accumulation of these substances. The pathogenesis-related (PR) genes expression represented by PR-1b was increased in EPS-treated plants. This is the first report of a systemic induction of protection triggered by EPS produced by Serratia sp. against CMV-Y.

  10. Biochemical study of leaf browning in minimally processed leaves of lettuce (Lactuca sativa L. var. acephala).

    Science.gov (United States)

    Degl'Innocenti, E; Guidi, L; Pardossi, A; Tognoni, F

    2005-12-28

    A series of biochemical parameters, including the concentration of total ascorbic acid (ASA(tot)) and the activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and peroxidases (PODs), was investigated during cold storage (72 h at 4 degrees C in the dark) in fresh-cut (minimally processed) leaves of two lettuce (Lactuca sativa L. var. acephala) cultivars differing in the susceptibility to tissue browning: Green Salade Bowl (GSB), susceptible, and Red Salade Bowl (RSB), resistant. The two cultivars showed differences also at the biochemical level. The content in ASA(tot) increased in RSB, as a consequence of increased DHA concentration; conversely, ASA(tot) diminished in GSB, in which ASA was not detectable after 72 h of storage, thus suggesting a disappearance of ascorbate (both ASA and DHA) into nonactive forms. The antioxidant capacity (as determined by using FRAP analysis) decreased significantly during storage in RSB, while a strong increase was observed in GSB. PAL activity increased soon after processing reaching a maximum by 3 h, then it declined to a relatively constant value in RSB, while in GSB it showed a tendency to decrease in the first few hours from harvest and processing. POD activity, at least for chlorogenic acid, increased significantly during storage only in GSB.

  11. UVA, UVB and UVC Light Enhances the Biosynthesis of Phenolic Antioxidants in Fresh-Cut Carrot through a Synergistic Effect with Wounding

    Directory of Open Access Journals (Sweden)

    Bernadeth B. Surjadinata

    2017-04-01

    Full Text Available Previously, we found that phenolic content and antioxidant capacity (AOX in carrots increased with wounding intensity. It was also reported that UV radiation may trigger the phenylpropanoid metabolism in plant tissues. Here, we determined the combined effect of wounding intensity and UV radiation on phenolic compounds, AOX, and the phenylalanine ammonia-lyase (PAL activity of carrots. Accordingly, phenolic content, AOX, and PAL activity increased in cut carrots with the duration of UVC radiation, whereas whole carrots showed no increase. Carrot pies showed a higher increase compared to slices and shreds. Phenolics, AOX, and PAL activity also increased in cut carrots exposed to UVA or UVB. The major phenolics were chlorogenic acid and its isomers, ferulic acid, and isocoumarin. The type of UV radiation affected phenolic profiles. Chlorogenic acid was induced by all UV radiations but mostly by UVB and UVC, ferulic acid was induced by all UV lights to comparable levels, while isocoumarin and 4,5-diCQA was induced mainly by UVB and UVC compared to UVA. In general, total phenolics correlated linearly with AOX for all treatments. A reactive oxygen species (ROS mediated hypothetical mechanism explaining the synergistic effect of wounding and different UV radiation stresses on phenolics accumulation in plants is herein proposed.

  12. Probing the active site of MIO-dependent 2,3-aminomutases, key catalysts in the biosynthesis of beta-amino acids incorporated in secondary metabolites

    Science.gov (United States)

    Bruner, Steven D.; Cooke, Heather

    2012-01-01

    The tyrosine aminomutase SgTAM produces (S)-β-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 α,β-unsaturated carboxylates. Studies of substrate specificity have been described for lyases but there have been no 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 α,β-unsaturated intermediates to form β-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 co-crystal 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

  13. Effect on isoflavone of soybean seedlings by 532nm laser irradiation

    Science.gov (United States)

    Tian, J.; Jin, L. H.; Li, J. M.; Shen, B. J.; Wang, C. Y.; Lu, X.; Zhao, X. L.

    2010-02-01

    We took soybeans as experimental substance to study how the 532nm laser with different power density and irradiation time affected the pullulation ratio of the soybeans, average height of seedlings and the isoflavone content of seedlings' cotyledon and laminae. The mechanism that laser pretreatment of soybean seeds could increase the isoflavone content of the seedlings was discussed in such both aspects as the efficiency of the photosynthesis and the activity of a phenylalanine ammonia-lyase (PAL) as an initial enzyme for synthesizing the isoflavone. The results showed that after the soybean seeds were pretreated by laser, the activity of the PAL and the resultants of the photosynthesis such as the sugar of dissolubility, the sucrose, and the amylum all increased with the soybean seeds irradiated by laser in which the effect on the soybean seeds pretreated by 15mW/mm2 laser for 5 min was the most obvious. As a result, the photosynthesis efficiency of the soybean seedlings increased after being pretreated by laser, which might offer the foundation for accumulating a large amount of isoflavone.

  14. A combination of biocontrol agents improves the management of dry root rot (Macrophomina phaseolina in greengram

    Directory of Open Access Journals (Sweden)

    R. Thilagavathi

    2007-08-01

    Full Text Available The biocontrol agents Trichoderma viride (strains Tv1 and Tv13, Pseudomonas fluorescens (Pf1 and Py15 and Bacillus subtilis (Bs16 were tested individually and in combination for their effectiveness against root rot of greengram caused by Macrophomina phaseolina. As regards the compatibility of the biocontrol agents with each other, T. viride strains were not compatible with B. subtilis (Bs16, but P. fluorescens strains were compatible with B. subtilis and T. viride. Of the biocontrol agents tested in vitro against M. phaseolina, combinations of P. fluorescens+T. viride (Pf1+Tv1, Pf1+Tv13 and Py15+Tv1 inhibited mycelial growth of the pathogen and they also promoted the growth of the greengram seedlings. A combination of Pf1+Tv1 was most effective in reducing root rot incidence under glass-house and field conditions as compared with other single or combined treatments or the untreated control. The activity of the defense-related enzymes peroxidase, polyphenol oxidase and phenyl alanine ammonia lyase was significantly greater in greengram plants treated with a talc based formulation containing Pf1+Tv1 followed by Pf1+Tv13 and Py15+Tv1, than in plants receiving other treatments or the untreated control. Moreover, a combination of Pf1+Tv1 followed by Pf1+Tv13 and Py15+Tv1 significantly increased yield under glass house and field conditions.

  15. Plant growth-promoting Methylobacterium induces defense responses in groundnut (Arachis hypogaea L.) compared with rot pathogens.

    Science.gov (United States)

    Madhaiyan, M; Suresh Reddy, B V; Anandham, R; Senthilkumar, M; Poonguzhali, S; Sundaram, S P; Sa, Tongmin

    2006-10-01

    This study, framed in two different phases, studied the plant-growth promotion and the induction of systemic resistance in groundnut by Methylobacterium. Seed imbibition with Methylobacterium sp. increased germination by 19.5% compared with controls. Combined inoculation of Methylobacterium sp. with Rhizobium sp. also significantly increased plant growth, nodulation, and yield attributes in groundnut compared with individual inoculation of Rhizobium sp. Methylobacterium sp. challenge-inoculated with Aspergillus niger/Sclerotium rolfsii in groundnut significantly enhanced germination percentage and seedling vigour and showed increased phenylalanine ammonia lyase (PAL), beta-1,3-glucanase, and peroxidase (PO) activities. Under pot-culture conditions, in Methylobacterium sp. seed-treated groundnut plants challenge-inoculated with A. niger/S. rolfsii through foliar sprays on day 30, the activities of enzymes PO, PAL, and beta-1,3-glucanase increased constantly from 24 to 72 hours, after which decreased activity was noted. Five isozymes of polyphenol oxidase and PO could be detected in Methylobacterium-treated plants challenged with A. niger/S. rolfsii. Induced systemic resistance activity in groundnut against rot pathogens in response to methylotrophic bacteria suggests the possibility that pink-pigmented facultative methylotrophic bacteria might be used as a means of biologic disease control.

  16. 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.

  17. Hyperhydricity in micropropagated carnation shoots: the role of oxidative stress.

    Science.gov (United States)

    Saher, Shady; Piqueras, Abel; Hellin, Eladio; Olmos, Enrique

    2004-01-01

    The physiology of hyperhydricity in relation to oxidative stress, mineral nutrients, antioxidant enzymes and ethylene has been studied in three micropropagated carnation cultivars under experimentally induced hyperhydricity. A marked increase in Fe content in comparison with normal tissues was observed in the hyperhydric tissues from the three cultivars. The levels of ethylene, solute leakage and malondialdehyde content were also significantly higher in the hyperhydric tissues. In relation to the time course of H(2)O(2) production measured by fluorescence quenching, a similar trend could be observed for the three cultivars, with a clear increase in the generation of hydrogen peroxide in hyperhydric tissues. The activities of all the antioxidative enzymes studied, except lipoxygenase, were higher in the hyperhydric shoots. Phenylalanine ammonia-lyase (PAL) showed a significant decrease in activity in the hyperhydric tissues in comparison with the controls for the three cultivars. Soluble guaiacol peroxidase had a strong increase in activity in hyperhydric shoots of the three cultivars. These results provide, for the first time, direct evidence of H(2)O(2) generation in hyperhydric tissues, characterize the response of the antioxidant system to an oxidative stress during hyperhydricity in carnation leaves and point to the accumulation of toxic forms of oxygen as the inducer of some of the abnormalities observed.

  18. Evidence for some signal transduction elements involved in UV-light-dependent responses in parsley protoplasts

    International Nuclear Information System (INIS)

    Frohnmeyer, H.; Bowler, C.; Schäfer, E.

    1997-01-01

    The signalling pathways used by UV-light are largely unknown. Using protoplasts from a heterotrophic parsley (Petroselinum crispum L.) cell culture that exclusively respond to UV-B light between 300 and 350 nm with a fast induction of genes encoding flavonoid biosynthetic enzymes, information was obtained about the UV-light signal transduction pathway for chalcone synthase (CHS) and phenylalanine ammonia-lyase (PAL) gene expression. Pharmacological effectors which influence intracellular calcium levels, calmodulin and the activity of serine/threonine kinases also changed the UV-light-dependent expression of these genes. This evaluation indicated the participation of these components on the UV-B-mediated signal transduction cascade to CHS. In contrast, neither membrane-permeable cyclic GMP nor the tyrosine kinase inhibitor genistein affected CHS or PAL expression. Similar results were obtained in protoplasts, which have been transiently transformed with CHS-promoter/GUS (β-glucuronidase) reporter fusion constructs. The involvement of calcium and calmodulin was further indicated in a cell-free light-responsive in vitro transcription system from evacuolated parsley protoplasts. In conclusion, there is evidence now that components of the UV-light-dependent pathway leading to the CHS-promoter are different from the previously characterized cGMP-dependent pathway to CHS utilized by phytochrome in soybean (Glycine max) and tomato seedlings (Lycopersicon esculentum). (author)

  19. Efficient aspartic acid production by a psychrophile-based simple biocatalyst.

    Science.gov (United States)

    Tajima, Takahisa; Hamada, Mai; Nakashimada, Yutaka; Kato, Junichi

    2015-10-01

    We previously constructed a Psychrophile-based Simple bioCatalyst (PSCat) reaction system, in which psychrophilic metabolic enzymes are inactivated by heat treatment, and used it here to study the conversion of aspartic acid from fumaric acid mediated by the activity of aspartate ammonia-lyase (aspartase). In Escherichia coli, the biosynthesis of aspartic acid competes with that of L-malic acid produced from fumaric acid by fumarase. In this study, E. coli aspartase was expressed in psychrophilic Shewanella livingstonensis Ac10 heat treated at 50 °C for 15 min. The resultant PSCat could convert fumaric acid to aspartic acid without the formation of L-malic acid because of heat inactivation of psychrophilic fumarase activity. Furthermore, alginate-immobilized PSCat produced high yields of aspartic acid and could be re-used nine times. The results of our study suggest that PSCat can be applied in biotechnological production as a new approach to increase the yield of target compounds.

  20. Oxidative and Molecular Responses in Capsicum annuum L. after Hydrogen Peroxide, Salicylic Acid and Chitosan Foliar Applications

    Science.gov (United States)

    Mejía-Teniente, Laura; de Dalia Durán-Flores, Flor; Chapa-Oliver, Angela María; Torres-Pacheco, Irineo; Cruz-Hernández, Andrés; González-Chavira, Mario M.; Ocampo-Velázquez, Rosalía V.; Guevara-González, Ramón G.

    2013-01-01

    Hydrogen peroxide (H2O2) is an important ROS molecule (Reactive oxygen species) that serves as a signal of oxidative stress and activation of signaling cascades as a result of the early response of the plant to biotic stress. This response can also be generated with the application of elicitors, stable molecules that induce the activation of transduction cascades and hormonal pathways, which trigger induced resistance to environmental stress. In this work, we evaluated the endogenous H2O2 production caused by salicylic acid (SA), chitosan (QN), and H2O2 elicitors in Capsicum annuum L. Hydrogen peroxide production after elicitation, catalase (CAT) and phenylalanine ammonia lyase (PAL) activities, as well as gene expression analysis of cat1, pal, and pathogenesis-related protein 1 (pr1) were determined. Our results displayed that 6.7 and 10 mM SA concentrations, and, 14 and 18 mM H2O2 concentrations, induced an endogenous H2O2 and gene expression. QN treatments induced the same responses in lesser proportion than the other two elicitors. Endogenous H2O2 production monitored during several days, showed results that could be an indicator for determining application opportunity uses in agriculture for maintaining plant alert systems against a stress. PMID:23676352

  1. Effect of foliar application of salicylic acid, hydrogen peroxide and a xyloglucan oligosaccharide on capsiate content and gene expression associatedwith capsinoids synthesis in Capsicum annuum L.

    Science.gov (United States)

    Zunun-Perez, A Y; Guevara-Figueroa, T; Jimenez-Garcia, S N; Feregrino-Perez, A A; Gautier, F; Guevara-Gonzalez, R G

    2017-06-01

    Capsinoids are non-pungent analogues of capsaicinoids in pepper (Capsicum spp). The absence of pungency, in addition to their biological activities similar to that of capsaicinoids such as anti-inflammatory, antimicrobial, and antioxidant properties, makes capsinoids an excellent option for increasing use in human and animal nutrition, as well as health and pharmaceutical industries. There are only few sources of pepper producing capsinoids, and one of them (accession 509-45-1), Capsicum annuum L., is a potential source for increasing capsinoids content using strategies as controlled elicitation during plant production in the greenhouse. In this research we evaluated the effect of weekly and one-day-before-harvest foliar applications of hydrogen peroxide, salicylic acid and a xyloglucan oligosaccharide on the concentration of capsiate in fruits of this pepper accession, as well as the gene expression of phenylalanine ammonia-lyase (pal), putative aminotransferase (pamt), capsaicin synthase (at3) and β-keto acyl synthase (kas). Results showed that the two tested concentrations of H2O2 significantly increased capsiate content and gene expression associated with capsaicinoids (pamt, at3 and kas) and the phenylpropanoids (pal) pathways. Plant yield was not affected using this induction strategy. Our results indicated that the pre-harvest and weekly application of hydrogen peroxide and xyloglucan oligosaccharide improved production of capsiate in C. annuum L.

  2. Interplant communication of tomato plants through underground common mycorrhizal networks.

    Science.gov (United States)

    Song, Yuan Yuan; Zeng, Ren Sen; Xu, Jian Feng; Li, Jun; Shen, Xiang; Yihdego, Woldemariam Gebrehiwot

    2010-10-13

    Plants can defend themselves to pathogen and herbivore attack by responding to chemical signals that are emitted by attacked plants. It is well established that such signals can be transferred through the air. In theory, plants can also communicate with each other through underground common mycorrhizal networks (CMNs) that interconnect roots of multiple plants. However, until now research focused on plant-to-plant carbon nutrient movement and there is no evidence that defense signals can be exchanged through such mycorrhizal hyphal networks. Here, we show that CMNs mediate plant-plant communication between healthy plants and pathogen-infected tomato plants (Lycopersicon esculentum Mill.). After establishment of CMNs with the arbuscular mycorrhizal fungus Glomus mosseae between tomato plants, inoculation of 'donor' plants with the pathogen Alternaria solani led to increases in disease resistance and activities of the putative defensive enzymes, peroxidase, polyphenol oxidase, chitinase, β-1,3-glucanase, phenylalanine ammonia-lyase and lipoxygenase in healthy neighbouring 'receiver' plants. The uninfected 'receiver' plants also activated six defence-related genes when CMNs connected 'donor' plants challenged with A. solani. This finding indicates that CMNs may function as a plant-plant underground communication conduit whereby disease resistance and induced defence signals can be transferred between the healthy and pathogen-infected neighbouring plants, suggesting that plants can 'eavesdrop' on defence signals from the pathogen-challenged neighbours through CMNs to activate defences before being attacked themselves.

  3. An Overview of Stress-Induced Resveratrol Synthesis in Grapes: Perspectives for Resveratrol-Enriched Grape Products

    Directory of Open Access Journals (Sweden)

    Mohidul Hasan

    2017-02-01

    Full Text Available Resveratrol is the most important stilbene phytoalexin synthesized naturally or induced in plants, as a part of their defense mechanism. Grapes and their derivative products, including juice and wine, are the most important natural sources of resveratrol, consisting of notably higher amounts than other natural sources like peanuts. Consumption of red wine with its presence of resveratrol explained the “French Paradox”. Hence, the demand of resveratrol from grapes is increasing. Moreover, as a natural source of resveratrol, grapes became very important in the nutraceutical industry for their benefits to human health. The accumulation of resveratrol in grape skin, juice, and wine has been found to be induced by the external stimuli: microbial infection, ultrasonication (US treatment, light-emitting diode (LED, ultra violet (UV irradiation, elicitors or signaling compounds, macronutrients, and fungicides. Phenylalanine ammonia lyase, cinnamate-4-hydroxylase, coumaroyl-CoA ligase, and stilbene synthase play a key role in the synthesis of resveratrol. The up-regulation of those genes have the positive relationship with the elicited accumulation of resveratrol. In this review, we encapsulate the effect of different external stimuli (biotic and abiotic stresses or signaling compounds in order to obtain the maximum accumulation of resveratrol in grape skin, leaves, juice, wine, and cell cultures.

  4. Light-induced Variation in Phenolic Compounds in Cabernet Sauvignon Grapes (Vitis vinifera L.) Involves Extensive Transcriptome Reprogramming of Biosynthetic Enzymes, Transcription Factors, and Phytohormonal Regulators

    Science.gov (United States)

    Sun, Run-Ze; Cheng, Guo; Li, Qiang; He, Yan-Nan; Wang, Yu; Lan, Yi-Bin; Li, Si-Yu; Zhu, Yan-Rong; Song, Wen-Feng; Zhang, Xue; Cui, Xiao-Di; Chen, Wu; Wang, Jun

    2017-01-01

    Light environments have long been known to influence grape (Vitis vinifera L.) berry development and biosynthesis of phenolic compounds, and ultimately affect wine quality. Here, the accumulation and compositional changes of hydroxycinnamic acids (HCAs) and flavonoids, as well as global gene expression were analyzed in Cabernet Sauvignon grape berries under sunlight exposure treatments at different phenological stages. Sunlight exposure did not consistently affect the accumulation of berry skin flavan-3-ol or anthocyanin among different seasons due to climatic variations, but increased HCA content significantly at véraison and harvest, and enhanced flavonol accumulation dramatically with its timing and severity degree trend. As in sunlight exposed berries, a highly significant correlation was observed between the expression of genes coding phenylalanine ammonia-lyase, 4-coumarate: CoA ligase, flavanone 3-hydroxylase and flavonol synthase family members and corresponding metabolite accumulation in the phenolic biosynthesis pathway, which may positively or negatively be regulated by MYB, bHLH, WRKY, AP2/EREBP, C2C2, NAC, and C2H2 transcription factors (TFs). Furthermore, some candidate genes required for auxin, ethylene and abscisic acid signal transductions were also identified which are probably involved in berry development and flavonoid biosynthesis in response to enhanced sunlight irradiation. Taken together, this study provides a valuable overview of the light-induced phenolic metabolism and transcriptome changes, especially the dynamic responses of TFs and signaling components of phytohormones, and contributes to the further understanding of sunlight-responsive phenolic biosynthesis regulation in grape berries. PMID:28469625

  5. 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.

  6. Cross-talk interactions of exogenous nitric oxide and sucrose modulates phenylpropanoid metabolism in yellow lupine embryo axes infected with Fusarium oxysporum.

    Science.gov (United States)

    Morkunas, Iwona; Formela, Magda; Floryszak-Wieczorek, Jolanta; Marczak, Łukasz; Narożna, Dorota; Nowak, Witold; Bednarski, Waldemar

    2013-10-01

    The aim of the study was to examine cross-talk of exogenous nitric oxide (NO) and sucrose in the mechanisms of synthesis and accumulation of isoflavonoids in embryo axes of Lupinus luteus L. cv. Juno. It was verified whether the interaction of these molecules can modulate the defense response of axes to infection and development of the pathogenic fungus Fusarium oxysporum f. sp. lupini. Sucrose alone strongly stimulated a high level of genistein glucoside in axes pretreated with exogenous nitric oxide (SNP or GSNO) and non-pretreated axes. As a result of amplification of the signal coming from sucrose and GSNO, high isoflavonoids accumulation was observed (+Sn+GSNO). It needs to be stressed that infection in tissues pretreated with SNP/GSNO and cultured on the medium with sucrose (+Si+SNP/+Si+GSNO) very strongly enhances the accumulation of free isoflavone aglycones. In +Si+SNP axes phenylalanine ammonia-lyase activity was high up to 72h. As early as at 12h in +Si+SNP axes an increase was recorded in gene expression level of the specific isoflavonoid synthesis pathway. At 24h in +Si+SNP axes a very high total antioxidant capacity dependent on the pool of fast antioxidants was noted. Post-infection generation of semiquinone radicals was lower in axes with a high level of sucrose than with a deficit. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  7. Development of Mesorhizobium ciceri-Based Biofilms and Analyses of Their Antifungal and Plant Growth Promoting Activity in Chickpea Challenged by Fusarium Wilt.

    Science.gov (United States)

    Das, Krishnashis; Rajawat, Mahendra Vikram Singh; Saxena, Anil Kumar; Prasanna, Radha

    2017-03-01

    Biofilmed biofertilizers have emerged as a new improved inoculant technology to provide efficient nutrient and pest management and sustain soil fertility. In this investigation, development of a Trichoderma viride - Mesorhizobium ciceri biofilmed inoculant was undertaken, which we hypothesized, would possess more effective biological nitrogen fixing ability and plant growth promoting properties. As a novel attempt, we selected Mesorhizobium ciceri spp. with good antifungal attributes with the assumption that such inoculants could also serve as biocontrol agents. These biofilms exhibited significant enhancement in several plant growth promoting attributes, including 13-21 % increase in seed germination, production of ammonia, IAA and more than onefold to twofold enhancement in phosphate solubilisation, when compared to their individual partners. Enhancement of 10-11 % in antifungal activity against Fusarium oxysporum f. sp. ciceri was also recorded, over the respective M. ciceri counterparts. The effect of biofilms and the M. ciceri cultures individual on growth parameters of chickpea under pathogen challenged soil illustrated that the biofilms performed at par with the M. ciceri strains for most plant biometrical and disease related attributes. Elicitation of defense related enzymes like l-phenylalanine ammonia lyase, peroxidase and polyphenol oxidase was higher in M. ciceri /biofilm treated plants as compared to uninoculated plants under pathogen challenged soil. Further work on the signalling mechanisms among the partners and their tripartite interactions with host plant is envisaged in future studies.

  8. Redox Signaling and CBF-Responsive Pathway Are Involved in Salicylic Acid-Improved Photosynthesis and Growth under Chilling Stress in Watermelon

    Science.gov (United States)

    Cheng, Fei; Lu, Junyang; Gao, Min; Shi, Kai; Kong, Qiusheng; Huang, Yuan; Bie, Zhilong

    2016-01-01

    Salicylic acid (SA) plays an important role in plant response to abiotic stresses. This study investigated the potential role of SA in alleviating the adverse effects of chilling stress on photosynthesis and growth in watermelon (Citrullus lanatus). Chilling stress induced the simultaneous accumulation of free and conjugated SA in watermelon plants, and the chilling-induced SA production was attributed to the phenylalanine ammonia-lyase pathway. Applying SA at moderate concentrations induced chilling tolerance, whereas inhibition of SA biosynthesis by L-α-aminooxy-β-phenylpropionic acid (AOPP) increased the photooxidation of PS II under chilling stress in watermelon, resulting in reduced photosynthesis and growth. Chilling induced a transient increase in the ratios of reduced to oxidized glutathione and reduced ascorbate to dehydroascorbate. Then, the expression of antioxidant genes was upregulated, and the activities of antioxidant enzymes were enhanced. Furthermore, SA-induced chilling tolerance was associated with cellular glutathione and ascorbate homeostasis, which served as redox signals to regulate antioxidant metabolism under chilling stress. AOPP treatment stimulated the chilling-induced expression of cold-responsive genes, particularly via C-repeat binding factors CBF3 and CBF4. These results confirm the synergistic role of SA signaling and the CBF-dependent responsive pathway during chilling stress in watermelon. PMID:27777580

  9. Redox Signaling and CBF-Responsive Pathway are Involved in Salicylic Acid-Improved Photosynthesis and Growth under Chilling Stress in Watermelon

    Directory of Open Access Journals (Sweden)

    Fei Cheng

    2016-10-01

    Full Text Available Salicylic acid (SA plays an important role in plant response to abiotic stresses. This study investigated the potential role of SA in alleviating the adverse effects of chilling stress on photosynthesis and growth in watermelon (Citrullus lanatus. Chilling stress induced the simultaneous accumulation of free and conjugated SA in watermelon plants, and the chilling-induced SA production was attributed to the phenylalanine ammonia-lyase pathway. Applying SA at moderate concentrations induced chilling tolerance, whereas inhibition of SA biosynthesis by L-ɑ-aminooxy-β-phenylpropionic acid (AOPP increased the photooxidation of PS II under chilling stress in watermelon, resulting in reduced photosynthesis and growth. Chilling induced a transient increase in the ratios of reduced to oxidized glutathione and reduced ascorbate to dehydroascorbate. Then, the expression of antioxidant genes was upregulated, and the activities of antioxidant enzymes were enhanced. Furthermore, SA-induced chilling tolerance was associated with cellular glutathione and ascorbate homeostasis, which served as redox signals to regulate antioxidant metabolism under chilling stress. AOPP treatment stimulated the chilling-induced expression of cold-responsive genes, particularly via C-repeat binding factors CBF3 and CBF4. These results confirm the synergistic role of SA signaling and the CBF-dependent responsive pathway during chilling stress in watermelon.

  10. Short UV-C Treatment Prevents Browning and Extends the Shelf-Life of Fresh-Cut Carambola

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    Carlota Moreno

    2017-01-01

    Full Text Available In this work, we selected a short UV-C treatment for fresh-cut carambola and assessed its efficacy in supplementing the benefits of low temperature storage. UV-C treated (6.0, 10.0, and 12.5 kJ m−2 carambola slices showed reduced deterioration compared to control fruit. Treatment with a dose of 12.5 kJ m−2 UV-C was more effective in maintaining quality and was selected for subsequent experiments evaluating the combination of UV-C and refrigeration on fruit storability and physical, chemical, and microbiological properties. Short UV-C exposure reduced weight loss and electrolyte leakage. UV-C treated carambola slices presented higher phenolic antioxidants than control after 21 d at 4°C and showed no alterations in soluble solids or titratable acidity. UV-C exposure also reduced the counts of molds, yeast, and aerobic mesophilic bacteria. UV-C treated fruit showed a fresh-like appearance even after 21 d as opposed to control carambola which presented spoilage and extensive browning symptoms. The reduction of fruit browning in UV-C treated fruit was not due to reduction in phenylalanine-ammonia lyase (PAL and/or peroxidase (POD, but rather through polyphenol oxidase (PPO inhibition and improved maintenance of tissue integrity.

  11. Effects of postharvest salicylic acid dipping on Alternaria rot and disease resistance of jujube fruit during storage.

    Science.gov (United States)

    Cao, Jiankang; Yan, Jiaqi; Zhao, Yumei; Jiang, Weibo

    2013-10-01

    Considerable postharvest losses caused by Alternaria alternata often occur in Chinese jujube fruit, and synthetic fungicides have been widely used to protect the fruit from Alternaria rot. However, the potential harmfulness of fungicide residues to human health and the environment cannot be ignored. This study was conducted to develop an alternative approach for controlling postharvest disease by inducing fruit resistance with salicylic acid (SA) dipping. Disease incidence and lesion area in the jujube fruit inoculated with A. alternata were significantly inhibited by 2 and 2.5 mmol L(-1) SA dipping. Naturally infected decay rate and index in jujubes were also significantly reduced by SA dipping during long-term storage at 0°C. SA enhanced activities of the main defense-related enzymes including phenylalanine ammonia-lyase, peroxidase, chitinase and β-1,3-glucanase in the fruit during storage. SA strongly decreased catalase activity but increased superoxide dismutase activity and ascorbic acid content in jujubes. The beneficial effects of SA on fruit protection may be due to its ability to activate several highly coordinated defence-related systems in jujubes, instead of its fungicidal activity. The findings indicated that application of SA would offer an alternative approach that helps to control postharvest disease and maintain storage quality in fruits. © 2013 Society of Chemical Industry.

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

    International Nuclear Information System (INIS)

    Thomas, P.; Srirangarajan, A.N.; Padwal-Desai, S.R.; Ghanekar, A.S.; Shirsat, S.G.; Pendharkar, M.B.; Nair, P.M.; Nadkarni, G.B.

    1978-01-01

    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 15 0 C belonged to Erwinia spp., while the rot caused below 10 0 C was essentially due to Micrococcus spp. Irradiation followed by storage at cool temperatures (10-15 0 C) offers an alternative method, comparable with conventional refrigerated (2-4 0 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)

  13. Expression of Genes Related to Phenylpropanoid Biosynthesis in Different Organs of Ixeris dentata var. albiflora.

    Science.gov (United States)

    Lee, Sang-Hoon; Park, Yun-Ji; Park, Sang Un; Lee, Sang-Won; Kim, Seong-Cheol; Jung, Chan-Sik; Jang, Jae-Ki; Hur, Yoonkang; Kim, Yeon Bok

    2017-05-30

    Members of the genus Ixeris have long been used in traditional medicines as stomachics, sedatives, and diuretics. Phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate: coenzyme-A (CoA) ligase (4CL), chalcone synthase (CHS), and dihydroflavonol 4-reductase (DFR) are important enzymes in the phenylpropanoid pathway. In this study, we analyzed seven genes from Ixeris dentata var. albiflora that are involved in phenylpropanoid biosynthesis, using an Illumina/Solexa HiSeq 2000 platform. The amino acid sequence alignments for IdPAL s, IdC4H, Id4CL s, IdCHS , and IdDFR showed high identity to sequences from other plants. We also investigated transcript levels using quantitative real-time PCR, and analyzed the accumulation of phenylpropanoids in different organs of I. dentata var. albiflora using high-performance liquid chromatography. The transcript levels of IdC4H, Id4CL1 , IdCHS , and IdDFR were highest in the leaf. The catechin, chlorogenic acid, ferulic acid, and quercetin contents were also highest in the leaf. We suggest that expression of IdC4H, Id4CL1 , IdCHS , and IdDFR is associated with the accumulation of phenylpropanoids. Our results may provide baseline information for elucidating the mechanism of phenylpropanoid biosynthesis in different organs of I. dentata var. albiflora .

  14. Engineering of Escherichia coli for the synthesis of N-hydroxycinnamoyl tryptamine and serotonin.

    Science.gov (United States)

    Lee, Su Jin; Sim, Geun-Young; Lee, Youngshim; Kim, Bong-Gyu; Ahn, Joong-Hoon

    2017-11-01

    Plants synthesize various phenol amides. Among them, hydroxycinnamoyl (HC) tryptamines and serotonins exhibit antioxidant, anti-inflammatory, and anti-atherogenic activities. We synthesized HC-tryptamines and HC-serotonin from several HCs and either tryptamine or serotonin using Escherichia coli harboring the 4CL (4-coumaroyl CoA ligase) and CaHCTT [hydroxycinnamoyl-coenzyme A:serotonin N-(hydroxycinnamoyl)transferase] genes. E. coli was engineered to synthesize N-cinnamoyl tryptamine from glucose. TDC (tryptophan decarboxylase) and PAL (phenylalanine ammonia lyase) along with 4CL and CaHCTT were introduced into E. coli and the phenylalanine biosynthetic pathway of E. coli was engineered. Using this strategy, approximately 110.6 mg/L of N-cinnamoyl tryptamine was synthesized. By feeding 100 μM serotonin into the E. coli culture, which could induce the synthesis of cinnamic acid or p-coumaric acid, more than 99 μM of N-cinnamoyl serotonin and N-(p-coumaroyl) serotonin were synthesized.

  15. Chemical products induce resistance to Xanthomonas perforans in tomato.

    Science.gov (United States)

    Itako, Adriana Terumi; Tolentino Júnior, João Batista; Silva Júnior, Tadeu Antônio Fernandes da; Soman, José Marcelo; Maringoni, Antonio Carlos

    2015-01-01

    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.

  16. Growth and phenolic compounds of Lactuca sativa L. grown in a closed-type plant production system with UV-A, -B, or -C lamp.

    Science.gov (United States)

    Lee, Min-Jeong; Son, Jung Eek; Oh, Myung-Min

    2014-01-30

    The production of high-quality crops based on phytochemicals is a strategy for accelerating the practical use of plant factories. Previous studies have demonstrated that ultraviolet (UV) light is effective in improving phytochemical production. This study aimed to determine the effect of various UV wavelengths on growth and phenolic compound accumulation in lettuce (Lactuca sativa L.) grown in a closed-type plant production system. Seven days, 1 day and 0.25 day were determined as the upper limit of the irradiation periods for UV-A, -B, and -C, respectively, in the lettuce based on physiological disorders and the fluorescence parameter F(v)/F(m). Continuous UV-A treatment significantly induced the accumulation of phenolic compounds and antioxidants until 4 days of treatment without growth inhibition, consistent with an increase in phenylalanine ammonia lyase (PAL) gene expression and PAL activity. Repeated or gradual UV-B exposure yielded approximately 1.4-3.6 times more total phenolics and antioxidants, respectively, than the controls did 2 days after the treatments, although both treatments inhibited lettuce growth. Repeated UV-C exposure increased phenolics but severely inhibited the growth of lettuce plants. Our data suggest that UV irradiation can improve the accumulation of phenolic compounds with antioxidant properties in lettuce cultivated in plant factories. © 2013 Society of Chemical Industry.

  17. Differential metabolism of L-phenylalanine in the formation of aromatic volatiles in melon (Cucumis melo L.) fruit.

    Science.gov (United States)

    Gonda, Itay; Davidovich-Rikanati, Rachel; Bar, Einat; Lev, Shery; Jhirad, Pliaa; Meshulam, Yuval; Wissotsky, Guy; Portnoy, Vitaly; Burger, Joseph; Schaffer, Arthur A; Tadmor, Yaakov; Giovannoni, James J; Fei, Zhangjun; Fait, Aaron; Katzir, Nurit; Lewinsohn, Efraim

    2018-04-01

    Studies on the active pathways and the genes involved in the biosynthesis of L-phenylalanine-derived volatiles in fleshy fruits are sparse. Melon fruit rinds converted stable-isotope labeled L-phe into more than 20 volatiles. Phenylpropanes, phenylpropenes and benzenoids are apparently produced via the well-known phenylpropanoid pathway involving phenylalanine ammonia lyase (PAL) and being (E)-cinnamic acid a key intermediate. Phenethyl derivatives seemed to be derived from L-phe via a separate biosynthetic route not involving (E)-cinnamic acid and PAL. To explore for a biosynthetic route to (E)-cinnamaldehyde in melon rinds, soluble protein cell-free extracts were assayed with (E)-cinnamic acid, CoA, ATP, NADPH and MgSO 4 , producing (E)-cinnamaldehyde in vitro. In this context, we characterized CmCNL, a gene encoding for (E)-cinnamic acid:coenzyme A ligase, inferred to be involved in the biosynthesis of (E)-cinnamaldehyde. Additionally we describe CmBAMT, a SABATH gene family member encoding a benzoic acid:S-adenosyl-L-methionine carboxyl methyltransferase having a role in the accumulation of methyl benzoate. Our approach leads to a more comprehensive understanding of L-phe metabolism into aromatic volatiles in melon fruit. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Participation of the phosphoinositide metabolism in the hypersensitive response of Citrus limon against Alternaria alternata

    Directory of Open Access Journals (Sweden)

    XIMENA ORTEGA

    2001-01-01

    Full Text Available Lemon seedlings inoculated with Alternaria alternata develop a hypersensitive response (HR that includes the induction of Phenylalanine ammonia-lyase (PAL, E. C. 4.3.1.5 and the synthesis of scoparone. The signal transduction pathway involved in the development of this response is unknown. We used several inhibitors of the Phosphoinositide (PI animal system to study a possible role of Inositol-1,4,5-triphosphate (IP3 in the transduction of the fungal conidia signal in Citrus limon. The HR was only partially inhibited by EGTA, suggesting that not only external but internal calcium as well are necessary for a complete development of the HR. In this plant system, Alternaria alternata induced an early accumulation of the second messenger IP3. When lemon seedlings were watered long term with LiCl, an inhibitor of the phosphoinositide cycle, the IP3 production was reduced, and the LiCl-watered plants could neither induce PAL nor synthesize scoparone in response to fungal conidia. Furthermore, neomycin, a Phospholipase C (PLC, E. C. 3.1.4.3 inhibitor, also inhibited PAL induction and scoparone synthesis in response to A. alternata. These results suggest that IP3 could be involved in the signal transduction pathway for the development of the HR of Citrus limon against A. alternata

  19. Identification of transcription factors ZmMYB111and ZmMYB148 involved in phenylpropanoid metabolism

    Directory of Open Access Journals (Sweden)

    Junjie eZhang

    2016-02-01

    Full Text Available Maize is the leading crop worldwide in terms of both planting area and total yields, but environmental stresses cause significant losses in productivity. Phenylpropanoid compounds play an important role in plant stress resistance; however, the mechanism of their synthesis is not fully understood, especially in regard to the expression and regulation of key genes. Phenylalanine ammonia-lyase (PAL is the first key enzyme involved in phenylpropanoid metabolism, and it has a significant effect on the synthesis of important phenylpropanoid compounds. According to the results of sequence alignments and functional prediction, we selected two conserved R2R3-MYB transcription factors as candidate genes for the regulation of phenylpropanoid metabolism. The two candidate R2R3-MYB genes, which we named ZmMYB111and ZmMYB148, were cloned, and then their structural characteristics and phylogenetic placement were predicted and analyzed. In addition, a series of evaluations were performed, including expression profiles, subcellular localization, transcription activation, protein-DNA interaction, and transient expression in maize endosperm. Our results indicated that both ZmMYB111 and ZmMYB148 are indeed R2R3-MYB transcription factors and that they may play a regulatory role in PAL gene expression.

  20. Regulation of Flavonoid Biosynthetic Genes in Germinating Arabidopsis Seedlings.

    Science.gov (United States)

    Kubasek, WL; Shirley, BW; McKillop, A; Goodman, HM; Briggs, W; Ausubel, FM

    1992-01-01

    Many higher plants, including Arabidopsis, transiently display purple anthocyanin pigments just after seed germination. We observed that steady state levels of mRNAs encoded by four flavonoid biosynthetic genes, PAL1 (encoding phenylalanine ammonia-lyase 1), CHS (encoding chalcone synthase), CHI (encoding chalcone isomerase), and DFR (encoding dihydroflavonol reductase), were temporally regulated, peaking in 3-day-old seedlings grown in continuous white light. Except for the case of PAL1 mRNA, mRNA levels for these flavonoid genes were very low in seedlings grown in darkness. Light induction studies using seedlings grown in darkness showed that PAL1 mRNA began to accumulate before CHS and CHI mRNAs, which, in turn, began to accumulate before DFR mRNA. This order of induction is the same as the order of the biosynthetic steps in flavonoid biosynthesis. Our results suggest that the flavonoid biosynthetic pathway is coordinately regulated by a developmental timing mechanism during germination. Blue light and UVB light induction experiments using red light- and dark-grown seedlings showed that the flavonoid biosynthetic genes are induced most effectively by UVB light and that blue light induction is mediated by a specific blue light receptor. PMID:12297632

  1. Direct Activation of Amidohydrolase Domain-Containing 1 Gene by Thyroid Hormone Implicates a Role in the Formation of Adult Intestinal Stem Cells During Xenopus Metamorphosis.

    Science.gov (United States)

    Okada, Morihiro; Miller, Thomas C; Fu, Liezhen; Shi, Yun-Bo

    2015-09-01

    The T3-dependent anuran metamorphosis resembles postembryonic development in mammals, the period around birth when plasma T3 levels peak. In particular, the remodeling of the intestine during metamorphosis mimics neonatal intestinal maturation in mammals when the adult intestinal epithelial self-renewing system is established. We have been using intestinal metamorphosis to investigate how the organ-specific adult stem cells are formed during vertebrate development. Early studies in Xenopus laevis have shown that this process involves complete degeneration of the larval epithelium and de novo formation of adult stem cells. A tissue-specific microarray analysis of intestinal gene expression during Xenopus laevis metamorphosis has identified a number of candidate stem cell genes. Here we have carried out detailed analyses of one such gene, amidohydrolase domain containing 1 (AMDHD1) gene, which encodes an enzyme in the histidine catabolic pathway. We show that AMDHD1 is exclusively expressed in the proliferating adult epithelial stem cells during metamorphosis with little expression in other intestinal tissues. We further provide evidence that T3 activates AMDHD1 gene expression directly at the transcription level through T3 receptor binding to the AMDHD1 gene in the intestine. In addition, we have reported earlier that histidine ammonia-lyase gene, another gene in histidine catabolic pathway, is similarly regulated by T3 in the intestine. These results together suggest that histidine catabolism plays a critical role in the formation and/or proliferation of adult intestinal stem cells during metamorphosis.

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

    International Nuclear Information System (INIS)

    Takayanagi, Tsutomu; Okuda, Tohru; Mine, Yohei; Yokotsuka, Koki

    2004-01-01

    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)

  3. Fungal Endophytes as a Metabolic Fine-Tuning Regulator for Wine Grape.

    Directory of Open Access Journals (Sweden)

    Ming-Zhi Yang

    Full Text Available Endophytes proved to exert multiple effects on host plants, including growth promotion, stress resistance. However, whether endophytes have a role in metabolites shaping of grape has not been fully understood. Eight endophytic fungal strains which originally isolated from grapevines were re-inoculated to field-grown grapevines in this study, and their effects on both leaves and berries of grapevines at maturity stage were assessed, with special focused on secondary metabolites and antioxidant activities. High-density inoculation of all these endophytic fungal strains modified the physio-chemical status of grapevine to different degrees. Fungal inoculations promoted the content of reducing sugar (RS, total flavonoids (TF, total phenols (TPh, trans-resveratrol (Res and activities of phenylalanine ammonia-lyase (PAL, in both leaves and berries of grapevine. Inoculation of endophytic fungal strains, CXB-11 (Nigrospora sp. and CXC-13 (Fusarium sp. conferred greater promotion effects in grape metabolic re-shaping, compared to other used fungal strains. Additionally, inoculation of different strains of fungal endophytes led to establish different metabolites patterns of wine grape. The work implies the possibility of using endophytic fungi as fine-tuning regulator to shape the quality and character of wine grape.

  4. 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.

  5. Synergistic Effects of l-Arginine and Methyl Salicylate on Alleviating Postharvest Disease Caused by Botrysis cinerea in Tomato Fruit.

    Science.gov (United States)

    Zhang, Xinhua; Min, Dedong; Li, Fujun; Ji, Nana; Meng, Demei; Li, Ling

    2017-06-21

    The effects of l-arginine (Arg, 1 mM) and/or methyl salicylate (MeSA, 0.05 mM) treatment on gray mold caused by Botrytis cinerea in tomato fruit were studied. Results indicated that Arg or MeSA alleviated the incidence and severity of fruit disease caused by B. cinerea, and that both Arg and MeSA (Arg + MeSA) further inhibited the development of fruit decay. Treatment with Arg + MeSA not only enhanced the activities of superoxide dismutase, catalase, and peroxidase but also promoted the expression levels of pathogenesis-related protein 1 gene and the activities of defense-related enzymes of phenylalanine ammonia-lyase, polyphenol oxidase, β-1,3-glucanase, and chitinase during most of the storage periods, which were associated with lower disease incidence and disease index. In addition, the combined treatment elevated the levels of total phenolics, polyamines, especially putrescine, and nitric oxide. These observations suggest that treatment of fruit with Arg + MeSA is an effective and promising way to alleviate postharvest decays on a commercial scale.

  6. 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)

  7. Enhanced Arabidopsis disease resistance against Botrytis cinerea induced by sulfur dioxide.

    Science.gov (United States)

    Xue, Meizhao; Yi, Huilan

    2018-01-01

    Sulfur dioxide (SO 2 ) is a common air pollutant that has complex impacts on plants. The effect of prior exposure to 30mgm -3 SO 2 on defence against Botrytis cinerea (B. cinerea) in Arabidopsis thaliana and the possible mechanisms of action were investigated. The results indicated that pre-exposure to 30mgm -3 SO 2 resulted in significantly enhanced resistance to B. cinerea infection. SO 2 pre-treatment significantly enhanced the activities of defence-related enzymes including phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), β-1,3-glucanase (BGL) and chitinase (CHI). Transcripts of the defence-related genes PAL, PPO, PR2, and PR3, encoding PAL, PPO, BGL and CHI, respectively, were markedly elevated in Arabidopsis plants pre-exposed to SO 2 and subsequently inoculated with B. cinerea (SO 2 + treatment group) compared with those that were only treated with SO 2 (SO 2 ) or inoculated with B. cinerea (CK+). Moreover, SO 2 pre-exposure also led to significant increases in the expression levels of MIR393, MIR160 and MIR167 in Arabidopsis. Meanwhile, the expression of known targets involved in the auxin signalling pathway, was negatively correlated with their corresponding miRNAs. Additionally, the transcript levels of the primary auxin-response genes GH3-like, BDL/IAA12, and AXR3/IAA17 were markedly repressed. Our findings indicate that 30mgm -3 SO 2 pre-exposure enhances disease resistance against B. cinerea in Arabidopsis by priming defence responses through enhancement of defence-related gene expression and enzyme activity, and miRNA-mediated suppression of the auxin signalling pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Defensive Responses of Rice Genotypes for Resistance Against Rice Leaffolder Cnaphalocrocis medinalis

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    M. PUNITHAVALLI

    2013-09-01

    Full Text Available The experiment was carried out to assess the reaction of different categories of rice genotypes viz., resistant, susceptible, hybrid, scented, popular and wild in response to the infestation by rice leaffolder (RLF, Cnaphalocrocis medinalis (Guenee and to explore the possible use of these genotypes in developing RLF-resistant rice varieties. The changes of various biochemical constituents such as leaf soluble protein, phenol, ortho-dihydroxy phenol, tannin and enzymes viz., peroxidase, phenyl alanine ammonia lyase (PAL were assessed spectrophotometrically in all the rice genotypes before and after RLF infestation. The protein profile was analyzed using sodium dodecyl sulphate-poly acrylamide gel electrophoresis (SDS-PAGE method. A significant constituent of biochemical content such as tannin, phenol and ortho-dihydroxy phenol has been increased along with enzyme activities of peroxidase and PAL in the infested resistant (Ptb 33, TKM6 and LFR831311 and wild rice genotypes (Oryza minuta and O. rhizomatis. A decrease in leaf protein content was evident invariably in all the infested rice genotypes. It is also evident that the contents of biochemicals such as phenol, ortho-dihydroxy phenol and tannin were negatively correlated with leaffolder damage. However, leaf protein content was positively correlated with the damage by rice leaffolder. SDS-PAGE analysis for total protein profiling of healthy and C. medinalis-infested genotypes revealed the enhanced expression of a high molecular weight (> 97 kDa protein in all the genotypes. Besides, there was also an increased induction of a 38 kDa protein in C. medinalis infested resistant genotypes, which was absent in uninfested plants. The present investigation proved that the elevated levels of biochemicals and enzymes may play a vital role in rice plants resistance to RLF.

  9. Gene expression in the lignin biosynthesis pathway during soybean seed development.

    Science.gov (United States)

    Baldoni, A; Von Pinho, E V R; Fernandes, J S; Abreu, V M; Carvalho, M L M

    2013-02-28

    The study of gene expression in plants is fundamental, and understanding the molecular mechanisms involved in important biological processes, such as biochemical pathways or signaling that are used or manipulated in improvement programs, are key for the production of high-quality soybean seeds. Reports related to gene expression of lignin in seeds are scarce in the literature. We studied the expression of the phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase, 4-hydroxycinnamate 3-hydroxylase, and cinnamyl alcohol dehydrogenase genes involved in lignin biosynthesis during the development of soybean (Glycine max L. Merrill) seeds. As the endogenous control, the eukaryotic elongation factor 1-beta gene was used in two biological replicates performed in triplicate. Relative quantitative expression of these genes during the R4, R5, R6, and R7 development stages was analyzed. Real-time polymerase chain reaction was used for the gene expression study. The analyses were carried out in an ABI PRISM 7500 thermocycler using the comparative Ct method and SYBR Green to detect amplification. The seed samples at the R4 stage were chosen as calibrators. Increased expression of the cinnamate-4-hydroxylase and PAL genes occurred in soybean seeds at the R5 and R6 development stages. The cinnamyl alcohol dehydrogenase gene was expressed during the final development phases of soybean seeds. In low-lignin soybean cultivars, the higher expression of the PAL gene occurs at development stages R6 and R7. Activation of the genes involved in the lignin biosynthesis pathway occurs at the beginning of soybean seed development.

  10. 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-.

  11. Caffeic acid production by simultaneous saccharification and fermentation of kraft pulp using recombinant Escherichia coli.

    Science.gov (United States)

    Kawaguchi, Hideo; Katsuyama, Yohei; Danyao, Du; Kahar, Prihardi; Nakamura-Tsuruta, Sachiko; Teramura, Hiroshi; Wakai, Keiko; Yoshihara, Kumiko; Minami, Hiromichi; Ogino, Chiaki; Ohnishi, Yasuo; Kondo, Ahikiko

    2017-07-01

    Caffeic acid (3,4-dihydroxycinnamic acid) serves as a building block for thermoplastics and a precursor for biologically active compounds and was recently produced from glucose by microbial fermentation. To produce caffeic acid from inedible cellulose, separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) reactions were compared using kraft pulp as lignocellulosic feedstock. Here, a tyrosine-overproducing Escherichia coli strain was metabolically engineered to produce caffeic acid from glucose by introducing the genes encoding a 4-hydroxyphenyllactate 3-hydroxylase (hpaBC) from Pseudomonas aeruginosa and tyrosine ammonia lyase (fevV) from Streptomyces sp. WK-5344. Using the resulting recombinant strain, the maximum yield of caffeic acid in SSF (233 mg/L) far exceeded that by SHF (37.9 mg/L). In the SSF with low cellulase loads (≤2.5 filter paper unit/g glucan), caffeic acid production was markedly increased, while almost no glucose accumulation was detected, indicating that the E. coli cells experienced glucose limitation in this culture condition. Caffeic acid yield was also negatively correlated with the glucose concentration in the fermentation medium. In SHF, the formation of by-product acetate and the accumulation of potential fermentation inhibitors increased significantly with kraft pulp hydrolysate than filter paper hydrolysate. The combination of these inhibitors had synergistic effects on caffeic acid fermentation at low concentrations. With lower loads of cellulase in SSF, less potential fermentation inhibitors (furfural, 5-hydroxymethyfurfural, and 4-hydroxylbenzoic acid) accumulated in the medium. These observations suggest that glucose limitation in SSF is crucial for improving caffeic acid yield, owing to reduced by-product formation and fermentation inhibitor accumulation.

  12. 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.

  13. Understanding Which Residues of the Active Site and Loop Structure of a Tyrosine Aminomutase Define Its Mutase and Lyase Activities.

    Science.gov (United States)

    Attanayake, Gayanthi; Walter, Tyler; Walker, Kevin D

    2018-05-30

    Site-directed mutations and substrate analogues were used to gain insights into the branch-point reaction of the 3,5-dihydro-5-methylidene-4 H-imidazol-4-one (MIO)-tyrosine aminomutase from Oryza sativa ( OsTAM). Exchanging the active residues of OsTAM (Y125C/N446K) for those in a phenylalanine aminomutase TcPAM altered its substrate specificity from tyrosine to phenylalanine. The aminomutase mechanism of OsTAM surprisingly changed almost exclusively to that of an ammonia lyase making cinnamic acid (>95%) over β-phenylalanine [Walter, T., et al. (2016) Biochemistry 55, 3497-3503]. We hypothesized that the missing electronics or sterics on the aryl ring of the phenylalanine substrate, compared with the sizable electron-donating hydroxyl of the natural tyrosine substrate, influenced the unexpected lyase reactivity of the OsTAM mutant. The double mutant was incubated with 16 α-phenylalanine substituent analogues of varying electronic strengths and sterics. The mutant converted each analogue principally to its acrylate with ∼50% conversion of the p-Br substrate, making only a small amount of the β-amino acid. The inner loop structure over the entrance to the active site was also mutated to assess how the lyase and mutase activities are affected. An OsTAM loop mutant, matching the loop residues of TcPAM, still chiefly made >95% of the acrylate from each substrate. A combined active site:loop mutant was most reactive but remained a lyase, making 10-fold more acrylates than other mutants did. While mutations within the active site changed the substrate specificity of OsTAM, continued exploration is needed to fully understand the interplay among the inner loop, the substrate, and the active site in defining the mutase and lyase activities.

  14. The Phenylpropanoid Pathway and Lignin in Defense against Ganoderma boninense Colonized Root Tissues in Oil Palm (Elaeis guineensis Jacq.

    Directory of Open Access Journals (Sweden)

    Nisha T. Govender

    2017-08-01

    Full Text Available Basal stem rot, caused by the basidiomycete fungus, Ganoderma boninense, is an economically devastating disease in Malaysia. Our study investigated the changes in lignin content and composition along with activity and expression of the phenylpropanoid pathway enzymes and genes in oil palm root tissues during G. boninense infection. We sampled control (non-inoculated and infected (inoculated seedlings at seven time points [1, 2, 3, 4, 8, and 12 weeks post-inoculation (wpi] in a randomized design. The expression profiles of phenylalanine ammonia lyase (PAL, cinnamyl alcohol dehydrogenase (CAD, and peroxidase (POD genes were monitored at 1, 2, and 3 wpi using real-time quantitative polymerase chain reaction. Seedlings at 4, 8, and 12 wpi were screened for lignin content, lignin composition, enzyme activities (PAL, CAD, and POD, growth (weight and height, and disease severity (DS. Gene expression analysis demonstrated up-regulation of PAL, CAD, and POD genes in the infected seedlings, relative to the control seedlings at 1, 2, and 3 wpi. At 2 and 3 wpi, CAD showed highest transcript levels compared to PAL and POD. DS increased progressively throughout sampling, with 5, 34, and 69% at 4, 8, and 12 wpi, respectively. Fresh weight and height of the infected seedlings were significantly lower compared to the control seedlings at 8 and 12 wpi. Lignin content of the infected seedlings at 4 wpi was significantly higher than the control seedlings, remained elicited with no change at 8 wpi, and then collapsed with a significant reduction at 12 wpi. The nitrobenzene oxidation products of oil palm root lignin yielded both syringyl and guaiacyl monomers. Accumulation of lignin in the infected seedlings was in parallel to increased syringyl monomers, at 4 and 8 wpi. The activities of PAL and CAD enzymes in the infected seedlings at DS = 5–34% were significantly higher than the control seedlings and thereafter collapsed at DS = 69%.

  15. Potential benefits and phytotoxicity of bulk and nano-chitosan on the growth, morphogenesis, physiology, and micropropagation of Capsicum annuum.

    Science.gov (United States)

    Asgari-Targhi, Ghasem; Iranbakhsh, Alireza; Ardebili, Zahra Oraghi

    2018-06-01

    Concerning environmental issues of metal based-nanomaterials and increasing demand for nano-based products; various strategies have been employed to find eco-friendly natural nano-compounds, among which nano-polymer chitosan is mostly considered. Herein, the various aspects of the way in which bulk or nano-chitosan may modify growth, morphogenesis, micropropagation, and physiology of Capsicum annuum L. were considered. Culture medium was manipulated with different concentrations of bulk chitosan or synthesized chitosan/tripolyphosphate (TPP) nano-particle. The supplementations of culture media led to changes in morphology (especially, the root architecture) and differentiation. Toxic doses of bulk (100 mgL -1 ) or nano-chitosan (5, 10, and 20 mgL -1 ) dramatically provoked cessation of plant growth and development. Plant growth and biomass accumulations were increased along with the suitable levels of bulk or nano-chitosan. Peroxidase and catalase activities in a dose and organ-dependent manners were significantly modified by the supplements. Phenylalanine ammonia lyase was induced by the mentioned supplements. Also, the contents of soluble phenols, proline, and alkaloid were found to be significantly increased by the elicitors, over the control. The nano-chitosan of 1 mgL -1 was found to be the most effective elicitor to trigger organogenesis via micropropagation. The huge differences between triggering and toxic concentrations of the supplements would be due to the physicochemical modifications of nano-polymeric. Furthermore, the results highlight the potential benefits (hormone-like activity) and phytotoxic impacts of nano-chitosan/TPP for in vitro manipulations. This is the first report on both the favorable and adverse effects of nano-chitosan/TPP, representing requirements for further investigation on such formulations for future applications. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  16. 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.

    Directory of Open Access Journals (Sweden)

    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.

  17. 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)

    Imai, T.; Terashima, N.; Yasuda, S.

    1997-01-01

    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

  18. Association of Rare Loss-Of-Function Alleles in HAL, Serum Histidine: Levels and Incident Coronary Heart Disease.

    Science.gov (United States)

    Yu, Bing; Li, Alexander H; Muzny, Donna; Veeraraghavan, Narayanan; de Vries, Paul S; Bis, Joshua C; Musani, Solomon K; Alexander, Danny; Morrison, Alanna C; Franco, Oscar H; Uitterlinden, André; Hofman, Albert; Dehghan, Abbas; Wilson, James G; Psaty, Bruce M; Gibbs, Richard; Wei, Peng; Boerwinkle, Eric

    2015-04-01

    Histidine is a semiessential amino acid with antioxidant and anti-inflammatory properties. Few data are available on the associations between genetic variants, histidine levels, and incident coronary heart disease (CHD) in a population-based sample. By conducting whole exome sequencing on 1152 African Americans in the Atherosclerosis Risk in Communities (ARIC) study and focusing on loss-of-function (LoF) variants, we identified 3 novel rare LoF variants in HAL, a gene that encodes histidine ammonia-lyase in the first step of histidine catabolism. These LoF variants had large effects on blood histidine levels (β=0.26; P=1.2×10(-13)). The positive association with histidine levels was replicated by genotyping an independent sample of 718 ARIC African Americans (minor allele frequency=1%; P=1.2×10(-4)). In addition, high blood histidine levels were associated with reduced risk of developing incident CHD with an average of 21.5 years of follow-up among African Americans (hazard ratio=0.18; P=1.9×10(-4)). This finding was validated in an independent sample of European Americans from the Framingham Heart Study (FHS) Offspring Cohort. However, LoF variants in HAL were not directly significantly associated with incident CHD after meta-analyzing results from the CHARGE Consortium. Three LoF mutations in HAL were associated with increased histidine levels, which in turn were shown to be inversely related to the risk of CHD among both African Americans and European Americans. Future investigations on the association between HAL gene variation and CHD are warranted. © 2015 American Heart Association, Inc.

  19. Transcriptome and metabolome reprogramming in Vitis vinifera cv. Trincadeira berries upon infection with Botrytis cinerea.

    Science.gov (United States)

    Agudelo-Romero, Patricia; Erban, Alexander; Rego, Cecília; Carbonell-Bejerano, Pablo; Nascimento, Teresa; Sousa, Lisete; Martínez-Zapater, José M; Kopka, Joachim; Fortes, Ana Margarida

    2015-04-01

    Vitis vinifera berries are sensitive towards infection by the necrotrophic pathogen Botrytis cinerea, leading to important economic losses worldwide. The combined analysis of the transcriptome and metabolome associated with fungal infection has not been performed previously in grapes or in another fleshy fruit. In an attempt to identify the molecular and metabolic mechanisms associated with the infection, peppercorn-sized fruits were infected in the field. Green and veraison berries were collected following infection for microarray analysis complemented with metabolic profiling of primary and other soluble metabolites and of volatile emissions. The results provided evidence of a reprogramming of carbohydrate and lipid metabolisms towards increased synthesis of secondary metabolites involved in plant defence, such as trans-resveratrol and gallic acid. This response was already activated in infected green berries with the putative involvement of jasmonic acid, ethylene, polyamines, and auxins, whereas salicylic acid did not seem to be involved. Genes encoding WRKY transcription factors, pathogenesis-related proteins, glutathione S-transferase, stilbene synthase, and phenylalanine ammonia-lyase were upregulated in infected berries. However, salicylic acid signalling was activated in healthy ripening berries along with the expression of proteins of the NBS-LRR superfamily and protein kinases, suggesting that the pathogen is able to shut down defences existing in healthy ripening berries. Furthermore, this study provided metabolic biomarkers of infection such as azelaic acid, a substance known to prime plant defence responses, arabitol, ribitol, 4-amino butanoic acid, 1-O-methyl- glucopyranoside, and several fatty acids that alone or in combination can be used to monitor Botrytis infection early in the vineyard. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email

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

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    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.

  1. The Antirrhinum AmDEL gene enhances flavonoids accumulation and salt and drought tolerance in transgenic Arabidopsis.

    Science.gov (United States)

    Wang, Feibing; Zhu, Hong; Kong, Weili; Peng, Rihe; Liu, Qingchang; Yao, Quanhong

    2016-07-01

    A basic helix-loop-helix (bHLH) transcription factor gene from Antirrhinum, AmDEL , increases flavonoids accumulation and enhances salt and drought tolerance via up-regulating flavonoid biosynthesis, proline biosynthesis and ROS scavenging genes in transgenic Arabidopsis. In plants, transcriptional regulation is the most important tools for increasing flavonoid biosynthesis. The AmDEL gene, as a basic helix-loop-helix transcription factor gene from Antirrhinum, has been shown to increase flavonoids accumulation in tomato. However, its role in tolerance to abiotic stresses has not yet been investigated. In this study, the codon-optimized AmDEL gene was chemically synthesized. Subcellular localization analysis in onion epidermal cells indicated that AmDEL protein was localized to the nucleus. Expression analysis in yeast showed that the full length of AmDEL exhibited transcriptional activation. Overexpression of AmDEL significantly increased flavonoids accumulation and enhanced salt and drought tolerance in transgenic Arabidopsis plants. Real-time quantitative PCR analysis showed that overexpression of AmDEL resulted in the up-regulation of genes involved in flavonoid biosynthesis, proline biosynthesis and ROS scavenging under salt and drought stresses. Meanwhile, Western blot and enzymatic analyses showed that the activities of phenylalanine ammonia lyase, chalcone isomerase, dihydroflavonol reductase, pyrroline-5-carboxylate synthase, superoxide dismutase and peroxidase were also increased. Further components analyses indicated that the significant increase of proline and relative water content and the significant reduction of H2O2 and malonaldehyde content were observed under salt and drought stresses. In addition, the rates of electrolyte leakage and water loss were reduced in transgenic plants. These findings imply functions of AmDEL in accumulation of flavonoids and tolerance to salt and drought stresses. The AmDEL gene has the potential to be used to increase

  2. Light-induced Variation in Phenolic Compounds in Cabernet Sauvignon Grapes (Vitis vinifera L. Involves Extensive Transcriptome Reprogramming of Biosynthetic Enzymes, Transcription Factors, and Phytohormonal Regulators

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    Jun Wang

    2017-04-01

    Full Text Available Light environments have long been known to influence grape (Vitis vinifera L. berry development and biosynthesis of phenolic compounds, and ultimately affect wine quality. Here, the accumulation and compositional changes of hydroxycinnamic acids (HCAs and flavonoids, as well as global gene expression were analyzed in Cabernet Sauvignon grape berries under sunlight exposure treatments at different phenological stages. Sunlight exposure did not consistently affect the accumulation of berry skin flavan-3-ol or anthocyanin among different seasons due to climatic variations, but increased HCA content significantly at véraison and harvest, and enhanced flavonol accumulation dramatically with its timing and severity degree trend. As in sunlight exposed berries, a highly significant correlation was observed between the expression of genes coding phenylalanine ammonia-lyase, 4-coumarate: CoA ligase, flavanone 3-hydroxylase and flavonol synthase family members and corresponding metabolite accumulation in the phenolic biosynthesis pathway, which may positively or negatively be regulated by MYB, bHLH, WRKY, AP2/EREBP, C2C2, NAC, and C2H2 transcription factors (TFs. Furthermore, some candidate genes required for auxin, ethylene and abscisic acid signal transductions were also identified which are probably involved in berry development and flavonoid biosynthesis in response to enhanced sunlight irradiation. Taken together, this study provides a valuable overview of the light-induced phenolic metabolism and transcriptome changes, especially the dynamic responses of TFs and signaling components of phytohormones, and contributes to the further understanding of sunlight-responsive phenolic biosynthesis regulation in grape berries.

  3. Light quality affects flavonoid production and related gene expression in Cyclocarya paliurus.

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    Liu, Yang; Fang, Shengzuo; Yang, Wanxia; Shang, Xulan; Fu, Xiangxiang

    2018-02-01

    Understanding the responses of plant growth and secondary metabolites to differential light conditions is very important to optimize cultivation conditions of medicinal woody plants. As a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. In this study, LED-based light including white light (WL), blue light (BL), red light (RL), and green light (GL) were used to affect leaf biomass production, flavonoid accumulation and related gene expression of one-year C. paliurus seedlings in controlled environments. After the treatments of 60 days, the highest leaf biomass appeared in the treatment of WL, while the lowest leaf biomass was found under GL. Compared to WL, the total flavonoid contents of C. paliurus leaves were significantly higher in BL, RL, and GL, but the highest values of selected flavonoids (kaempferol, isoquercitrin and quercetin) were observed under BL. Furthermore, the greatest yields of total and selected flavonoids in C. paliurus leaves per seedling were also achieved under BL, indicating that blue light was effective for inducing the production of flavonoids in C. paliurus leaves. Pearson's correlation analysis showed that there were significantly positive correlations between leaf flavonoid content and relative gene expression of key enzymes (phenylalanine ammonia lyase, PAL; 4-coumaroyl CoA-ligase, 4CL; and chalcone synthase, CHS) in the upstream, which converting phenylalanine into the flavonoid skeleton of tetrahydroxy chalcone. It is concluded that manipulating light quality may be potential mean to achieve the highest yields of flavonoids in C. paliurus cultivation, however this needs to be further verified by more field trials. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Real time expression of ACC oxidase and PR-protein genes mediated by Methylobacterium spp. in tomato plants challenged with Xanthomonas campestris pv. vesicatoria.

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    Yim, W J; Kim, K Y; Lee, Y W; Sundaram, S P; Lee, Y; Sa, T M

    2014-07-15

    Biotic stress like pathogenic infection increases ethylene biosynthesis in plants and ethylene inhibitors are known to alleviate the severity of plant disease incidence. This study aimed to reduce the bacterial spot disease incidence in tomato plants caused by Xanthomonas campestris pv. vesicatoria (XCV) by modulating stress ethylene with 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity of Methylobacterium strains. Under greenhouse condition, Methylobacterium strains inoculated and pathogen challenged tomato plants had low ethylene emission compared to pathogen infected ones. ACC accumulation and ACC oxidase (ACO) activity with ACO related gene expression increased in XCV infected tomato plants over Methylobacterium strains inoculated plants. Among the Methylobacterium spp., CBMB12 resulted lowest ACO related gene expression (1.46 Normalized Fold Expression), whereas CBMB20 had high gene expression (3.42 Normalized Fold Expression) in pathogen challenged tomato. But a significant increase in ACO gene expression (7.09 Normalized Fold Expression) was observed in the bacterial pathogen infected plants. In contrast, Methylobacterium strains enhanced β-1,3-glucanase and phenylalanine ammonia-lyase (PAL) enzyme activities in pathogen challenged tomato plants. The respective increase in β-1,3-glucanase related gene expressions due to CBMB12, CBMB15, and CBMB20 strains were 66.3, 25.5 and 10.4% higher over pathogen infected plants. Similarly, PAL gene expression was high with 0.67 and 0.30 Normalized Fold Expression, in pathogen challenged tomato plants inoculated with CBMB12 and CBMB15 strains. The results suggest that ethylene is a crucial factor in bacterial spot disease incidence and that methylobacteria with ACC deaminase activity can reduce the disease severity with ultimate pathogenesis-related protein increase in tomato. Copyright © 2014 Elsevier GmbH. All rights reserved.

  5. 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.

  6. 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.

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    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.

  7. Physcomitrella patens activates reinforcement of the cell wall, programmed cell death and accumulation of evolutionary conserved defence signals, such as salicylic acid and 12-oxo-phytodienoic acid, but not jasmonic acid, upon Botrytis cinerea infection.

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    Ponce De León, Inés; Schmelz, Eric A; Gaggero, Carina; Castro, Alexandra; Álvarez, Alfonso; Montesano, Marcos

    2012-10-01

    The moss Physcomitrella patens is an evolutionarily basal model system suitable for the analysis of plant defence responses activated after pathogen assault. Upon infection with the necrotroph Botrytis cinerea, several defence mechanisms are induced in P. patens, including the fortification of the plant cell wall by the incorporation of phenolic compounds and the induced expression of related genes. Botrytis cinerea infection also activates the accumulation of reactive oxygen species and cell death with hallmarks of programmed cell death in moss tissues. Salicylic acid (SA) levels also increase after fungal infection, and treatment with SA enhances transcript accumulation of the defence gene phenylalanine ammonia-lyase (PAL) in P. patens colonies. The expression levels of the genes involved in 12-oxo-phytodienoic acid (OPDA) synthesis, including lipoxygenase (LOX) and allene oxide synthase (AOS), increase in P. patens gametophytes after pathogen assault, together with a rise in free linolenic acid and OPDA concentrations. However, jasmonic acid (JA) could not be detected in healthy or infected tissues of this plant. Our results suggest that, although conserved defence signals, such as SA and OPDA, are synthesized and are probably involved in the defence response of P. patens against B. cinerea infection, JA production appears to be missing. Interestingly, P. patens responds to OPDA and methyl jasmonate by reducing moss colony growth and rhizoid length, suggesting that jasmonate perception is present in mosses. Thus, P. patens can provide clues with regard to the evolution of different defence pathways in plants, including signalling and perception of OPDA and jasmonates in nonflowering and flowering plants. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

  8. Phenylketonuria: translating research into novel therapies

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    Ho, Gladys

    2014-01-01

    Phenylketonuria (PKU) is an inborn error of metabolism of the amino acid phenylalanine. It is an autosomal recessive disorder with a rate of incidence of 1 in 10,000 in Caucasian populations. Mutations in the phenylalanine hydroxylase (PAH) gene are the major cause of PKU, due to the loss of the catalytic activity of the enzyme product PAH. Newborn screening for PKU allows early intervention, avoiding irreparable neurological damage and intellectual disability that would arise from untreated PKU. The current primary treatment of PKU is the limitation of dietary protein intake, which in the long term may be associated with poor compliance in some cases and other health problems due to malnutrition. The only alternative therapy currently approved is the supplementation of BH4, the requisite co-factor of PAH, in the orally-available form of sapropterin dihydrochloride. This treatment is not universally available, and is only effective for a proportion (estimated 30%) of PKU patients. Research into novel therapies for PKU has taken many different approaches to address the lack of PAH activity at the core of this disorder: enzyme replacement via virus-mediated gene transfer, transplantation of donor liver and recombinant PAH protein, enzyme substitution using phenylalanine ammonia lyase (PAL) to provide an alternative pathway for the metabolism of phenylalanine, and restoration of native PAH activity using chemical chaperones and nonsense read-through agents. It is hoped that continuing efforts into these studies will translate into a significant improvement in the physical outcome, as well as quality of life, for patients with PKU. PMID:26835324

  9. De novo transcriptome sequencing of black pepper (Piper nigrum L.) and an analysis of genes involved in phenylpropanoid metabolism in response to Phytophthora capsici.

    Science.gov (United States)

    Hao, Chaoyun; Xia, Zhiqiang; Fan, Rui; Tan, Lehe; Hu, Lisong; Wu, Baoduo; Wu, Huasong

    2016-10-21

    Piper nigrum L., or "black pepper", is an economically important spice crop in tropical regions. Black pepper production is markedly affected by foot rot disease caused by Phytophthora capsici, and genetic improvement of black pepper is essential for combating foot rot diseases. However, little is known about the mechanism of anti- P. capsici in black pepper. The molecular mechanisms underlying foot rot susceptibility were studied by comparing transcriptome analysis between resistant (Piper flaviflorum) and susceptible (Piper nigrum cv. Reyin-1) black pepper species. 116,432 unigenes were acquired from six libraries (three replicates of resistant and susceptible black pepper samples), which were integrated by applying BLAST similarity searches and noted by adopting Kyoto Encyclopaedia of Genes and Gene Ontology (GO) genome orthology identifiers. The reference transcriptome was mapped using two sets of digital gene expression data. Using GO enrichment analysis for the differentially expressed genes, the majority of the genes associated with the phenylpropanoid biosynthesis pathway were identified in P. flaviflorum. In addition, the expression of genes revealed that after susceptible and resistant species were inoculated with P. capsici, the majority of genes incorporated in the phenylpropanoid metabolism pathway were up-regulated in both species. Among various treatments and organs, all the genes were up-regulated to a relatively high degree in resistant species. Phenylalanine ammonia lyase and peroxidase enzyme activity increased in susceptible and resistant species after inoculation with P. capsici, and the resistant species increased faster. The resistant plants retain their vascular structure in lignin revealed by histochemical analysis. Our data provide critical information regarding target genes and a technological basis for future studies of black pepper genetic improvements, including transgenic breeding.

  10. Nitrogen Limited Red and Green Leaf Lettuce Accumulate Flavonoid Glycosides, Caffeic Acid Derivatives, and Sucrose while Losing Chlorophylls, Β-Carotene and Xanthophylls.

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    Becker, Christine; Urlić, Branimir; Jukić Špika, Maja; Kläring, Hans-Peter; Krumbein, Angelika; Baldermann, Susanne; Goreta Ban, Smiljana; Perica, Slavko; Schwarz, Dietmar

    2015-01-01

    Reduction of nitrogen application in crop production is desirable for ecological and health-related reasons. Interestingly, nitrogen deficiency can lead to enhanced concentrations of polyphenols in plants. The reason for this is still under discussion. The plants' response to low nitrogen concentration can interact with other factors, for example radiation intensity. We cultivated red and green leaf lettuce hydroponically in a Mediterranean greenhouse, supplying three different levels of nitrogen (12 mM, 3 mM, 0.75 mM), either in full or reduced (-50%) radiation intensity. In both red and green lettuce, we found clear effects of the nitrogen treatments on growth characteristics, phenolic and photosynthetic compounds, nitrogen, nitrate and carbon concentration of the plants. Interestingly, the concentrations of all main flavonoid glycosides, caffeic acid derivatives, and sucrose increased with decreasing nitrogen concentration, whereas those of chlorophylls, β-carotene, neoxanthin, lactucaxanthin, all trans- and cis-violaxanthin decreased. The constitutive concentrations of polyphenols were lower in the green cultivar, but their relative increase was more pronounced than in the red cultivar. The constitutive concentrations of chlorophylls, β-carotene, neoxanthin, all trans- and cis-violaxanthin were similar in red and green lettuce and with decreasing nitrogen concentration they declined to a similar extent in both cultivars. We only detected little influence of the radiation treatments, e.g. on anthocyanin concentration, and hardly any interaction between radiation and nitrogen concentration. Our results imply a greater physiological plasticity of green compared to the red lettuce regarding its phenolic compounds. They support the photoprotection theory regarding anthocyanins as well as the theory that the deamination activity of phenylalanine ammonia-lyase drives phenylpropanoid synthesis.

  11. Nitrogen Limited Red and Green Leaf Lettuce Accumulate Flavonoid Glycosides, Caffeic Acid Derivatives, and Sucrose while Losing Chlorophylls, Β-Carotene and Xanthophylls

    Science.gov (United States)

    Becker, Christine; Urlić, Branimir; Jukić Špika, Maja; Kläring, Hans-Peter; Krumbein, Angelika; Baldermann, Susanne; Goreta Ban, Smiljana; Perica, Slavko; Schwarz, Dietmar

    2015-01-01

    Reduction of nitrogen application in crop production is desirable for ecological and health-related reasons. Interestingly, nitrogen deficiency can lead to enhanced concentrations of polyphenols in plants. The reason for this is still under discussion. The plants’ response to low nitrogen concentration can interact with other factors, for example radiation intensity. We cultivated red and green leaf lettuce hydroponically in a Mediterranean greenhouse, supplying three different levels of nitrogen (12 mM, 3 mM, 0.75 mM), either in full or reduced (-50%) radiation intensity. In both red and green lettuce, we found clear effects of the nitrogen treatments on growth characteristics, phenolic and photosynthetic compounds, nitrogen, nitrate and carbon concentration of the plants. Interestingly, the concentrations of all main flavonoid glycosides, caffeic acid derivatives, and sucrose increased with decreasing nitrogen concentration, whereas those of chlorophylls, β-carotene, neoxanthin, lactucaxanthin, all trans- and cis-violaxanthin decreased. The constitutive concentrations of polyphenols were lower in the green cultivar, but their relative increase was more pronounced than in the red cultivar. The constitutive concentrations of chlorophylls, β-carotene, neoxanthin, all trans- and cis-violaxanthin were similar in red and green lettuce and with decreasing nitrogen concentration they declined to a similar extent in both cultivars. We only detected little influence of the radiation treatments, e.g. on anthocyanin concentration, and hardly any interaction between radiation and nitrogen concentration. Our results imply a greater physiological plasticity of green compared to the red lettuce regarding its phenolic compounds. They support the photoprotection theory regarding anthocyanins as well as the theory that the deamination activity of phenylalanine ammonia-lyase drives phenylpropanoid synthesis. PMID:26569488

  12. Synergistic effect of the combined bio-fungicides ε-poly-l-lysine and chitooligosaccharide in controlling grey mould (Botrytis cinerea) in tomatoes.

    Science.gov (United States)

    Sun, Guangzheng; Yang, Qichao; Zhang, Ancheng; Guo, Jia; Liu, Xinjie; Wang, Yang; Ma, Qing

    2018-07-02

    The antifungal properties and the induction of resistance by ε-poly-l-lysine (ε-PL) and chitooligosaccharide (COS) were examined to find an alternative to synthetic fungicides currently used in the control of the devastating fungal pathogen Botrytis cinerea, the causal agent of grey mould disease of tomatoes. As presented herein, this combined treatment (200 mg/L ε-PL + 400 mg/L COS) was found to have optimal in vitro antifungal activities, achieving an inhibition rate of 90.22%. In vivo assays with these combined bio-fungicides, under greenhouse conditions using susceptible tomato plants, demonstrated good protection against severe grey mould. In field tests, the combined bio-fungicides had a control effect of up to 66.67% against tomato grey mould. To elucidate the mechanisms of the combined bio-fungicide-induced resistance in the tomato, plants were subjected to three treatments: 1) inoculation with B. cinerea after spraying with 200 mg/L ε-PL alone, 2) inoculation with the combined bio-fungicides, and 3) inoculation with 400 mg/L COS alone. Compared to the control (sterile water), increases in salicylic acid (SA) and jasmonic acid (JA) levels and increased phenylalanine ammonia lyase (PAL), peroxidase (POD), and superoxide dismutase (SOD) activities were observed. Catalase (CAT) activity and abscisic acid (ABA) and gibberellin (GA) levels decreased, particularly in the combined bio-fungicide-treated plants. Altogether, these findings reveal that the combined bio-fungicides (200 mg/L ε-PL + 400 mg/L COS) should be an excellent biocontrol agent candidate that combines direct antifungal activity against B. cinerea with plant resistance. Copyright © 2018. Published by Elsevier B.V.

  13. A horizontal gene transfer at the origin of phenylpropanoid metabolism: a key adaptation of plants to land.

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    Emiliani, Giovanni; Fondi, Marco; Fani, Renato; Gribaldo, Simonetta

    2009-02-16

    The pioneering ancestor of land plants that conquered terrestrial habitats around 500 million years ago had to face dramatic stresses including UV radiation, desiccation, and microbial attack. This drove a number of adaptations, among which the emergence of the phenylpropanoid pathway was crucial, leading to essential compounds such as flavonoids and lignin. However, the origin of this specific land plant secondary metabolism has not been clarified. We have performed an extensive analysis of the taxonomic distribution and phylogeny of Phenylalanine Ammonia Lyase (PAL), which catalyses the first and essential step of the general phenylpropanoid pathway, leading from phenylalanine to p-Coumaric acid and p-Coumaroyl-CoA, the entry points of the flavonoids and lignin routes. We obtained robust evidence that the ancestor of land plants acquired a PAL via horizontal gene transfer (HGT) during symbioses with soil bacteria and fungi that are known to have established very early during the first steps of land colonization. This horizontally acquired PAL represented then the basis for further development of the phenylpropanoid pathway and plant radiation on terrestrial environments. Our results highlight a possible crucial role of HGT from soil bacteria in the path leading to land colonization by plants and their subsequent evolution. The few functional characterizations of sediment/soil bacterial PAL (production of secondary metabolites with powerful antimicrobial activity or production of pigments) suggest that the initial advantage of this horizontally acquired PAL in the ancestor of land plants might have been either defense against an already developed microbial community and/or protection against UV.

  14. 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)

    Yassin, Sh.M.; El-Neshawy, S.M.; Aly, A.Z.; Abdel Kader, D.A.

    2012-01-01

    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

  15. The Phenylpropanoid Pathway and Lignin in Defense against Ganoderma boninense Colonized Root Tissues in Oil Palm (Elaeis guineensis Jacq.).

    Science.gov (United States)

    Govender, Nisha T; Mahmood, Maziah; Seman, Idris A; Wong, Mui-Yun

    2017-01-01

    Basal stem rot, caused by the basidiomycete fungus, Ganoderma boninense , is an economically devastating disease in Malaysia. Our study investigated the changes in lignin content and composition along with activity and expression of the phenylpropanoid pathway enzymes and genes in oil palm root tissues during G. boninense infection. We sampled control (non-inoculated) and infected (inoculated) seedlings at seven time points [1, 2, 3, 4, 8, and 12 weeks post-inoculation (wpi)] in a randomized design. The expression profiles of phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD) genes were monitored at 1, 2, and 3 wpi using real-time quantitative polymerase chain reaction. Seedlings at 4, 8, and 12 wpi were screened for lignin content, lignin composition, enzyme activities (PAL, CAD, and POD), growth (weight and height), and disease severity (DS). Gene expression analysis demonstrated up-regulation of PAL, CAD, and POD genes in the infected seedlings, relative to the control seedlings at 1, 2, and 3 wpi. At 2 and 3 wpi, CAD showed highest transcript levels compared to PAL and POD. DS increased progressively throughout sampling, with 5, 34, and 69% at 4, 8, and 12 wpi, respectively. Fresh weight and height of the infected seedlings were significantly lower compared to the control seedlings at 8 and 12 wpi. Lignin content of the infected seedlings at 4 wpi was significantly higher than the control seedlings, remained elicited with no change at 8 wpi, and then collapsed with a significant reduction at 12 wpi. The nitrobenzene oxidation products of oil palm root lignin yielded both syringyl and guaiacyl monomers. Accumulation of lignin in the infected seedlings was in parallel to increased syringyl monomers, at 4 and 8 wpi. The activities of PAL and CAD enzymes in the infected seedlings at DS = 5-34% were significantly higher than the control seedlings and thereafter collapsed at DS = 69%.

  16. 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.

  17. Changes in element accumulation, phenolic metabolism, and antioxidative enzyme activities in the red-skin roots of Panax ginseng.

    Science.gov (United States)

    Zhou, Ying; Yang, Zhenming; Gao, Lingling; Liu, Wen; Liu, Rongkun; Zhao, Junting; You, Jiangfeng

    2017-07-01

    Red-skin root disease has seriously decreased the quality and production of Panax ginseng (ginseng). To explore the disease's origin, comparative analysis was performed in different parts of the plant, particularly the epidermis, cortex, and/or fibrous roots of 5-yr-old healthy and diseased red-skin ginseng. The inorganic element composition, phenolic compound concentration, reactive oxidation system, antioxidant concentrations such as ascorbate and glutathione, activities of enzymes related to phenolic metabolism and oxidation, and antioxidative system particularly the ascorbate-glutathione cycle were examined using conventional methods. Aluminum (Al), iron (Fe), magnesium, and phosphorus were increased, whereas manganese was unchanged and calcium was decreased in the epidermis and fibrous root of red-skin ginseng, which also contained higher levels of phenolic compounds, higher activities of the phenolic compound-synthesizing enzyme phenylalanine ammonia-lyase and the phenolic compound oxidation-related enzymes guaiacol peroxidase and polyphenoloxidase. As the substrate of guaiacol peroxidase, higher levels of H 2 O 2 and correspondingly higher activities of superoxide dismutase and catalase were found in red-skin ginseng. Increased levels of ascorbate and glutathione; increased activities of l-galactose 1-dehydrogenase, ascorbate peroxidase, ascorbic acid oxidase, and glutathione reductase; and lower activities of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione peroxidase were found in red-skin ginseng. Glutathione- S -transferase activity remained constant. Hence, higher element accumulation, particularly Al and Fe, activated multiple enzymes related to accumulation of phenolic compounds and their oxidation. This might contribute to red-skin symptoms in ginseng. It is proposed that antioxidant and antioxidative enzymes, especially those involved in ascorbate-glutathione cycles, are activated to protect against phenolic compound

  18. Photosynthetic and biochemical mechanisms of an EMS-mutagenized cowpea associated with its resistance to cowpea severe mosaic virus.

    Science.gov (United States)

    Souza, Pedro F N; Silva, Fredy D A; Carvalho, Fabricio E L; Silveira, Joaquim A G; Vasconcelos, Ilka M; Oliveira, Jose T A

    2017-01-01

    The seed treatment of a CPSMV-susceptible cowpea genotype with the mutagenic agent EMS generated mutagenized resistant plantlets that respond to the virus challenge by activating biochemical and physiological defense mechanisms. Cowpea is an important crop that makes major nutritional contributions particularly to the diet of the poor population worldwide. However, its production is low, because cowpea is naturally exposed to several abiotic and biotic stresses, including viral agents. Cowpea severe mosaic virus (CPSMV) drastically affects cowpea grain production. This study was conducted to compare photosynthetic and biochemical parameters of a CPSMV-susceptible cowpea (CE-31 genotype) and its derived ethyl methanesulfonate-mutagenized resistant plantlets, both challenged with CPSMV, to shed light on the mechanisms of virus resistance. CPSMV inoculation was done in the fully expanded secondary leaves, 15 days after planting. At 7 days post-inoculation, in vivo photosynthetic parameters were measured and leaves collected for biochemical analysis. CPSMV-inoculated mutagenized-resistant cowpea plantlets (MCPI) maintained higher photosynthesis index, chlorophyll, and carotenoid contents in relation to the susceptible (CE-31) CPSMV-inoculated cowpea (CPI). Visually, the MCPI leaves did not exhibit any viral symptoms neither the presence of the virus as examined by RT-PCR. In addition, MCPI showed higher SOD, GPOX, chitinase, and phenylalanine ammonia lyase activities, H 2 O 2 , phenolic contents, and cell wall lignifications, but lower CAT and APX activities in comparison to CPI. All together, these photosynthetic and biochemical changes might have contributed for the CPSMS resistance of MCPI. Contrarily, CPI plantlets showed CPSMV accumulation, severe disease symptoms, reduction in the photosynthesis-related parameters, chlorophyll, carotenoid, phenolic compound, and H 2 O 2 contents, in addition to increased β-1,3-glucanase, and catalase activities that might have

  19. Characterization of Benzoyl Coenzyme A Biosynthesis Genes in the Enterocin-Producing Bacterium “Streptomyces maritimus”

    Science.gov (United States)

    Xiang, Longkuan; Moore, Bradley S.

    2003-01-01

    The novel benzoyl coenzyme A (benzoyl-CoA) biosynthesis pathway in “Streptomyces maritimus” was investigated through a series of target-directed mutations. Genes involved in benzoyl-CoA formation were disrupted through single-crossover homologous recombination, and the resulting mutants were analyzed for their ability to biosynthesize the benzoyl-CoA-primed polyketide antibiotic enterocin. Inactivation of the unique phenylalanine ammonia-lyase-encoding gene encP was previously shown to be absolutely required for benzoyl-CoA formation in “S. maritimus”. The fatty acid β-oxidation-related genes encH, -I, and -J, on the other hand, are necessary but not required. In each case, the yield of benzoyl-CoA-primed enterocin dropped below wild-type levels. We attribute the reduced benzoyl-CoA formation in these specific mutants to functional substitution and cross-talk between the products of genes encH, -I, and -J and the enzyme homologues of primary metabolism. Disruption of the benzoate-CoA ligase encN gene did not perturb enterocin production, however, demonstrating that encN is extraneous and that benzoic acid is not a pathway intermediate. EncN rather serves as a substitute pathway for utilizing exogenous benzoic acid. These experiments provide further support that benzoyl-CoA is formed in a novel bacterial pathway that resembles the eukaryotic assembly of benzoyl-CoA from phenylalanine via a β-oxidative path. PMID:12511484

  20. Transcriptome Analysis Reveals Molecular Signatures of Luteoloside Accumulation in Senescing Leaves of Lonicera macranthoides

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    Zexiong Chen

    2018-03-01

    Full Text Available Lonicera macranthoides is an important medicinal plant widely used in traditional Chinese medicine. Luteoloside is a critical bioactive compound in L. macranthoides. To date, the molecular mechanisms underlying luteoloside biosynthesis are still largely unknown. In this work, high performance liquid chromatography (HPLC was employed to determine the luteoloside contents in leaves, stems, and flowers at different developmental stages. Results showed that senescing leaves can accumulate large amounts of luteoloside, extremely higher than that in young and semi-lignified leaves and other tissues. RNA-Seq analysis identified that twenty-four differentially expressed unigenes (DEGs associated with luteoloside biosynthesis were significantly up-regulated in senescing leaves, which are positively correlated with luteoloside accumulation. These DEGs include phenylalanine ammonia lyase 2, cinnamate 4-hydroxylase 2, thirteen 4-coumarate-CoA ligases, chalcone synthase 2, six flavonoid 3′-monooxygenase (F3′H and two flavone 7-O-β-glucosyltransferase (UFGT genes. Further analysis demonstrated that two F3′Hs (CL11828.Contig1 and CL11828.Contig2 and two UFGTs (Unigene2918 and Unigene97915 might play vital roles in luteoloside generation. Furthermore, several transcription factors (TFs related to flavonoid biosynthesis including MYB, bHLH and WD40, were differentially expressed during leaf senescence. Among these TFs, MYB12, MYB75, bHLH113 and TTG1 were considered to be key factors involved in the regulation of luteoloside biosynthesis. These findings provide insights for elucidating the molecular signatures of luteoloside accumulation in L. macranthoides.

  1. 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.

  2. Evaluation of the significance of cell wall polymers in flax infected with a pathogenic strain of Fusarium oxysporum.

    Science.gov (United States)

    Wojtasik, Wioleta; Kulma, Anna; Dymińska, Lucyna; Hanuza, Jerzy; Czemplik, Magdalena; Szopa, Jan

    2016-03-22

    Fusarium oxysporum infection leads to Fusarium-derived wilt, which is responsible for the greatest losses in flax (Linum usitatissimum) crop yield. Plants infected by Fusarium oxysporum show severe symptoms of dehydration due to the growth of the fungus in vascular tissues. As the disease develops, vascular browning and leaf yellowing can be observed. In the case of more virulent strains, plants die. The pathogen's attack starts with secretion of enzymes degrading the host cell wall. The main aim of the study was to evaluate the role of the cell wall polymers in the flax plant response to the infection in order to better understand the process of resistance and develop new ways to protect plants against infection. For this purpose, the expression of genes involved in cell wall polymer metabolism and corresponding polymer levels were investigated in flax seedlings after incubation with Fusarium oxysporum. This analysis was facilitated by selecting two groups of genes responding differently to the infection. The first group comprised genes strongly affected by the infection and activated later (phenylalanine ammonia lyase and glucosyltransferase). The second group comprised genes which are slightly affected (up to five times) and their expression vary as the infection progresses. Fusarium oxysporum infection did not affect the contents of cell wall polymers, but changed their structure. The results suggest that the role of the cell wall polymers in the plant response to Fusarium oxysporum infection is manifested through changes in expression of their genes and rearrangement of the cell wall polymers. Our studies provided new information about the role of cellulose and hemicelluloses in the infection process, the change of their structure and the expression of genes participating in their metabolism during the pathogen infection. We also confirmed the role of pectin and lignin in this process, indicating the major changes at the mRNA level of lignin metabolism genes

  3. A wild 'albino' bilberry (Vaccinium myrtillus L. from Slovenia shows three bottlenecks in the anthocyanin pathway and significant differences in the expression of several regulatory genes compared to the common blue berry type.

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    Zala Zorenc

    Full Text Available Relative expressions of structural genes and a number of transcription factors of the anthocyanin pathway relevant in Vaccinium species, and related key enzyme activities were compared with the composition and content of metabolites in skins of ripe fruits of wild albino and blue bilberry (Vaccinium myrtillus found in Slovenia. Compared to the common blue type, the albino variant had a 151-fold lower total anthocyanin and a 7-fold lower total phenolic content in their berry skin, which correlated with lower gene expression of flavonoid 3-O-glycosyltransferase (FGT; 33-fold, flavanone 3-hydroxylase (FHT; 18-fold, anthocyanidin synthase (ANS; 11-fold, chalcone synthase (CHS, 7.6-fold and MYBPA1 transcription factor (22-fold. The expression of chalcone isomerase (CHI, dihydroflavonol 4-reductase (DFR, leucoanthocyanidin reductase (LAR, anthocyanidin reductase (ANR and MYBC2 transcription factor was reduced only by a factor of 1.5-2 in the albino berry skins, while MYBR3 and flavonoid 3',5'-hydroxylase (F3'5'H were increased to a similar extent. Expression of the SQUAMOSA class transcription factor TDR4, in contrast, was independent of the color type and does therefore not seem to be correlated with anthocyanin formation in this variant. At the level of enzymes, significantly lower FHT and DFR activities, but not of phenylalanine ammonia-lyase (PAL and CHS/CHI, were observed in the fruit skins of albino bilberries. A strong increase in relative hydroxycinnamic acid derivative concentrations indicates the presence of an additional bottleneck in the general phenylpropanoid pathway at a so far unknown step between PAL and CHS.

  4. Exogenous Melatonin Application Delays Senescence of Kiwifruit Leaves by Regulating the Antioxidant Capacity and Biosynthesis of Flavonoids

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    Dong Liang

    2018-04-01

    Full Text Available Melatonin, a multiple signal molecule, plays important roles in delaying senescence during the development of plants. Because few species have been studied for the effect of exogenous melatonin on anti-aging, the plausible mechanism of melatonin of anti-aging effects on other plant species has remained largely unknown. In the present study, the effects of exogenous melatonin on leaf senescence in kiwifruit were examined during natural aging after melatonin (200 μM or water (Control pretreatment. The decreased membrane damage and lower hydrogen peroxide (H2O2 content due to the enhanced scavenging activity of antioxidant enzymes peroxidase (POD, superoxide dismutase (SOD, and catalase (CAT demonstrated that melatonin effectively delayed the aging of kiwifruit leaves. Likewise, owing to up-regulated expression of chlorophyll a/b-binding protein (CAB gene in the sampled leaves pretreated with melatonin, chlorophyll degradation decreased. Therefore, osmoregulatory substances in sampled leaves accumulated (e.g., soluble sugar and soluble protein and seedling cell environment stability was maintained. Simultaneously, melatonin decreased H2O2 concentration owing to increased glutathione (GSH and ascorbate (AsA content, and the expression levels of glutathione reductase (GR, ascorbate peroxidase (APX, monodehydroascorbate reductase (MDAR, dehydroascorbate reductase (DHAR were up-regulated by melatonin application, indicating that the increase of GSH and AsA was attributed to the expression of these genes. In addition, a large amount of flavonoids accumulated in seedlings pretreated with melatonin, and transcript levels of eight genes involved in flavonoid synthesis, including phenylalanine ammonia-lyase (PAL, cinnamate-4-hydroxymate (C4H, chalcone synthase (CHS, flavanone 3-hydroxylase (F3H, flavonol synthase (FNS, leucoanthocyanin reductase (LAR, anthocyanin reductase (ANR, flavonoid 3-O-glucosyltransferase (UFGT were enhanced in response to melatonin

  5. A de novo transcriptomic approach to identify flavonoids and anthocyanins switch-off in olive (Olea europaea L. drupes at different stages of maturation

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    Domenico eIaria

    2016-01-01

    Full Text Available 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 information regarding metabolic processes, including those linked to fruit pigmentation in the olive.

  6. In situ localization of phenylpropanoid biosynthetic mRNAs and proteins in Parsley (Petroselinum crispum)

    International Nuclear Information System (INIS)

    Reinold, S.; Hahlbrock, K.

    1997-01-01

    Using in situ RNA/RNA hybridization, enzyme immunolocalization, and histochemical techniques, several phenylpropanoid biosynthetic activities and products were localized in tissue sections from various aerial parts of parsley (Petroselinum crispum) plants at different developmental stages. The enzymes and corresponding mRNAs analyzed included two representatives of general phenylpropanoid metabolism: phenylalanine ammonia-lyase (PAL) and 4-coumarate: CoA ligase (4CL), and one representative each from two distinct branch pathways: chalcone synthase (CHS; flavonoids) and S-adenosyl-L-methionine: bergaptol O-methyltransferase (BMT; furanocoumarins). In almost all cases, the relative timing of accumulation differed greatly for mRNA and protein and indicated short expression periods and short half-lives for all mRNAs as compared to the proteins. PAL and 4CL occurred almost ubiquitously in cell type-specific patterns, and their mRNAs and proteins were always coordinately expressed, whereas the cell type-specific localization of flavonoid and furanocoumarin biosynthetic activities was to a large extent mutually exclusive. However, the distribution patterns of CHS and BMT, when superimposed, closely matched those of PAL and 4CL in nearly all tissues analysed, suggesting that the flavonoid and furanocoumarin pathways together constituted a large majority of the total phenylpropanoid biosynthetic activity. Differential sites of synthesis and accumulation indicating intercellular translocation were observed both for flavonoids and for furanocoumarins in oil ducts and the surrounding tissue. The widespread occurrence of both classes of compounds, as well as selected, pathway-specific mRNAs and enzymes, in many cell types of all parsley organs including various flower parts suggests additional functions beyond the previously established roles of flavonoids in UV protection and furanocoumarins in pathogen defence. (author)

  7. 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)

    Logemann, E.; Wu ShengCheng; Schröder, J.; Schmelzer, E.; Somssich, I.E.; Hahlbrock, K.

    1995-01-01

    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

  8. Isolation of a potential biocontrol agent Paenibacillus polymyxa NSY50 from vinegar waste compost and its induction of host defense responses against Fusarium wilt of cucumber.

    Science.gov (United States)

    Du, Nanshan; Shi, Lu; Yuan, Yinghui; Sun, Jin; Shu, Sheng; Guo, Shirong

    2017-09-01

    Fusarium wilt caused by Fusarium oxysporum f. sp. cucumerinum (FOC) is one of the major destructive soil-borne diseases infecting cucumber. In this study, we screened 60 target strains isolated from vinegar waste compost, from which 10 antagonistic strains were identified to have the disease suppression capacity of bio-control agents. The 16S rDNA gene demonstrated that the biocontrol agents were Paenibacillus polymyxa (P. polymyxa), Bacillus amyloliquefaciens (B. amyloliquefaciens) and Bacillus licheniformis (B. licheniformis). Based on the results of antagonistic activity experiments and pot experiment, an interesting strain of P. polymyxa (named NSY50) was selected for further research. Morphological, physiological and biochemical characteristics indicated that this strain was positive for protease and cellulase and produced indole acetic acid (22.21±1.27μg mL -1 ) and 1-aminocyclopropane-1-carboxylate deaminase (ACCD). NSY50 can significantly up-regulate the expression level of defense related genes PR1 and PR5 in cucumber roots at the early stages upon challenge with FOC. However, the gene expression levels of a set of defense-related genes, such as the plant nucleotide-binding site (NBS)-leucine-rich repeat (LRR) gene family (e.g., Csa001236, Csa09775, Csa018159), 26kDa phloem protein (Csa001568, Csa003306), glutathione-S-transferase (Csa017734) and phenylalanine ammonia-lyase (Csa002864) were suppressed by pretreatment with NSY50 compared with the single challenge with FOC after nine days of inoculation. Of particular interest was the reduced expression of these genes at disease progression stages, which may be required for F. oxysporum dependent necrotrophic disease development. Copyright © 2017 Elsevier GmbH. All rights reserved.

  9. Trichoderma harzianum elicits induced resistance in sunflower challenged by Rhizoctonia solani.

    Science.gov (United States)

    Singh, B N; Singh, A; Singh, B R; Singh, H B

    2014-03-01

    To investigate the efficacy of Trichoderma harzianum NBRI-1055 (denoted as 'T-1055') in suppression of seedling blight of sunflower caused by Rhizoctonia solani Kühn and their impact on host defence responses. T-1055 was applied as seed treatment, soil application and combined application (seed treatment + soil application). Higher protection afforded by combined application of T-1055 was associated with the marked induction of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (PO) and cinnamyl alcohol dehydrogenase (CAD) activities. The activities of PAL and PPO reached maximum at 10 days after sowing (DAS), while PO and CAD levels reached maximum at 12 DAS. This was further supported by the accumulation of total phenolic content that showed an increase up to threefold at 14 DAS. In addition, HPLC analysis revealed that the contents of ferulic and p-coumaric acids increased by 6·3 and 4·6 times, respectively, at 14 DAS. Amount of gallic acid was also little more than double. Lignin deposition in sunflower root increased by 2·7, 3·4 and 3·7 times through combined application of T-1055 at 16, 18 and 20 DAS, respectively. Combined application also increased the accumulation of PR-2 and PR-3 proteins by 3·3 and 3·9 times, respectively, at 12 DAS in followed by seed treatment alone. The combined application of T-1055 triggered defence responses in an enhanced level in sunflower than the soil and seed alone and provided better protection against Rhizoctonia seedling blight. Rhizospheric fungal bioagent 'T-1055' can enhance protection in sunflower against the R. solani pathogen through augmented elicitation of host defence responses. © 2013 The Society for Applied Microbiology.

  10. 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. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  11. 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'

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    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'.

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

    International Nuclear Information System (INIS)

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

    2002-01-01

    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 -

  13. Comparison of silicon nanoparticles and silicate treatments in fenugreek.

    Science.gov (United States)

    Nazaralian, Sanam; Majd, Ahmad; Irian, Saeed; Najafi, Farzaneh; Ghahremaninejad, Farrokh; Landberg, Tommy; Greger, Maria

    2017-06-01

    Silicon (Si) fertilization improves crop cultivation and is commonly added in the form of soluble silicates. However, most natural plant-available Si originates from plant formed amorphous SiO 2 particles, phytoliths, similar to SiO 2 -nanoparticles (SiNP). In this work we, therefore, compared the effect by sodium silicate and that of SiNP on Si accumulation, activity of antioxidative stress enzymes catalase, peroxidase, superoxide dismutase, lignification of xylem cell walls and activity of phenylalanine ammonia-lyase (PAL) as well as expression of genes for the putative silicon transporter (PST), defensive (Tfgd 1) and phosphoenolpyruvate carboxykinase (PEPCK) and protein in fenugreek (Trigonella foenum-graecum L.) grown in hydroponics. The results showed that Si was taken up from both silicate and SiNP treatments and increasing sodium silicate addition increased the translocation of Si to the shoot, while this was not shown with increasing SiNP addition. The silicon transporter PST was upregulated at a greater level when sodium silicate was added compared with SiNP addition. There were no differences in effects between sodium silicate and SiNP treatments on the other parameters measured. Both treatments increased the uptake and accumulation of Si, xylem cell wall lignification, cell wall thickness, PAL activity and protein concentration in seedlings, while there was no effect on antioxidative enzyme activity. Tfgd 1 expression was strongly downregulated in leaves at Si addition. The similarity in effects by silicate and SiNP would be due to that SiNP releases silicate, which may be taken up, shown by a decrease in SiNP particle size with time in the medium. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Haijing Yi

    Full Text Available 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.

  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. 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

  17. Light Influences How the Fungal Toxin Deoxynivalenol Affects Plant Cell Death and Defense Responses

    Directory of Open Access Journals (Sweden)

    Khairul I. Ansari

    2014-02-01

    Full Text Available The Fusarium mycotoxin deoxynivalenol (DON can cause cell death in wheat (Triticum aestivum, but can also reduce the level of cell death caused by heat shock in Arabidopsis (Arabidopsis thaliana cell cultures. We show that 10 μg mL−1 DON does not cause cell death in Arabidopsis cell cultures, and its ability to retard heat-induced cell death is light dependent. Under dark conditions, it actually promoted heat-induced cell death. Wheat cultivars differ in their ability to resist this toxin, and we investigated if the ability of wheat to mount defense responses was light dependent. We found no evidence that light affected the transcription of defense genes in DON-treated roots of seedlings of two wheat cultivars, namely cultivar CM82036 that is resistant to DON-induced bleaching of spikelet tissue and cultivar Remus that is not. However, DON treatment of roots led to genotype-dependent and light-enhanced defense transcript accumulation in coleoptiles. Wheat transcripts encoding a phenylalanine ammonia lyase (PAL gene (previously associated with Fusarium resistance, non-expressor of pathogenesis-related genes-1 (NPR1 and a class III plant peroxidase (POX were DON-upregulated in coleoptiles of wheat cultivar CM82036 but not of cultivar Remus, and DON-upregulation of these transcripts in cultivar CM82036 was light enhanced. Light and genotype-dependent differences in the DON/DON derivative content of coleoptiles were also observed. These results, coupled with previous findings regarding the effect of DON on plants, show that light either directly or indirectly influences the plant defense responses to DON.

  18. The root hair assay facilitates the use of genetic and pharmacological tools in order to dissect multiple signalling pathways that lead to programmed cell death.

    Directory of Open Access Journals (Sweden)

    Joanna Kacprzyk

    Full Text Available The activation of programmed cell death (PCD is often a result of complex signalling pathways whose relationship and intersection are not well understood. We recently described a PCD root hair assay and proposed that it could be used to rapidly screen genetic or pharmacological modulators of PCD. To further assess the applicability of the root hair assay for studying multiple signalling pathways leading to PCD activation we have investigated the crosstalk between salicylic acid, autophagy and apoptosis-like PCD (AL-PCD in Arabidopsis thaliana. The root hair assay was used to determine rates of AL-PCD induced by a panel of cell death inducing treatments in wild type plants treated with chemical modulators of salicylic acid synthesis or autophagy, and in genetic lines defective in autophagy or salicylic acid signalling. The assay demonstrated that PCD induced by exogenous salicylic acid or fumonisin B1 displayed a requirement for salicylic acid signalling and was partially dependent on the salicylic acid signal transducer NPR1. Autophagy deficiency resulted in an increase in the rates of AL-PCD induced by salicylic acid and fumonisin B1, but not by gibberellic acid or abiotic stress. The phenylalanine ammonia lyase-dependent salicylic acid synthesis pathway contributed only to death induced by salicylic acid and fumonisin B1. 3-Methyladenine, which is commonly used as an inhibitor of autophagy, appeared to influence PCD induction in all treatments suggesting a possible secondary, non-autophagic, effect on a core component of the plant PCD pathway. The results suggest that salicylic acid signalling is negatively regulated by autophagy during salicylic acid and mycotoxin-induced AL-PCD. However, this crosstalk does not appear to be directly involved in PCD induced by gibberellic acid or abiotic stress. This study demonstrates that the root hair assay is an effective tool for relatively rapid investigation of complex signalling pathways leading to

  19. Salicylic Acid Alleviates Aluminum Toxicity in Soybean Roots through Modulation of Reactive Oxygen Species Metabolism

    Directory of Open Access Journals (Sweden)

    Ning Liu

    2017-11-01

    Full Text Available As an important signal molecule, salicylic acid (SA improves plant tolerance to aluminum (Al stress. The objective of this study was to investigate the effects of exogenous SA application on the dynamics of endogenous SA and reactive oxygen species in soybean (Glycine max L. exposed to Al stress. The roots of soybean seedlings were exposed to a combination of AlCl3 (30 μM and SA (10 μM/PAC (100 μM, paclobutrazol, SA biosynthesis inhibitor for 3, 6, 9, and 12 h. Al stress induced an increase in endogenous SA concentration in a time-dependent manner, also verified by the up-regulated expression of GmNPR1, an SA-responsive gene. Al stress increased the activities of phenylalanine ammonia-lyase (PAL and benzoic acid 2-hydroxylase (BA2H, and the contents of SA, O2- and malondialdehyde (MDA in the root apex. The application of exogenous SA increased PAL and BA2H, and reduced O2- and MDA contents in soybean roots under Al stress. PAC inhibited the SA induced increase in BA2H activity. In addition, the SA application resulted in a rapid increase in hydrogen peroxide (H2O2 concentration under Al stress, followed by a sharp decrease. Compared with the plants exposed to Al alone, Al+SA plants possessed higher activities of superoxide dismutase, peroxidase, and ascorbate peroxidase, and lower catalase activity, indicating that SA alleviated Al-induced oxidative damage. These results suggested that PAL and BA2H were involved in Al-induced SA production and showed that SA alleviated the adverse effects of Al toxicity by modulating the cellular H2O2 level and the antioxidant enzyme activities in the soybean root apex.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shiliang, E-mail: liushiliang9@163.com [College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan 611130 (China); Yang, Rongjie; Pan, Yuanzhi [College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan 611130 (China); Ren, Bo [Institute of Biotechnology & Breeding, Sichuan Academy of Forestry, Chengdu, Sichuan 610081 (China); Chen, Qibing; Li, Xi [College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan 611130 (China); Xiong, Xi [College of Agriculture, Food & Natural Resources, University of Missouri, Columbia, MO 65211 (United States); Tao, Jianjun [College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan 611130 (China); Cheng, Qingsu [Division of Life Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Department of Electrical & Biomedical Engineering, University of Nevada, Reno, NV 89557 (United States); Ma, Mingdong, E-mail: 610245498@qq.com [College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan 611130 (China)

    2016-08-15

    Highlights: • Endogenous NO and ROS accumulation were inversely related. • Selected amino acids in the roots were increased by SNP. • NO induced regulation of phenolic metabolism for protection against Cu toxicity. • SNP improved the vincristine, vinblastine and total alkaloid contents in Cu-treated plants. - Abstract: 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, 50 μM) alone or in combination on the well-known medicinal plant Catharanthus roseus L. were investigated. Our results showed that Cu markedly increased Cu{sup 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.

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

    International Nuclear Information System (INIS)

    Nigro, F.; Ippolito, A.; Salerno, M.; Lattanzio, V.

    2000-01-01

    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

  2. Plant Growth Promotion and Suppression of Bacterial Leaf Blight in Rice by Inoculated Bacteria.

    Directory of Open Access Journals (Sweden)

    Sumera Yasmin

    Full Text Available The present study was conducted to evaluate the potential of rice rhizosphere associated antagonistic bacteria for growth promotion and disease suppression of bacterial leaf blight (BLB. A total of 811 rhizospheric bacteria were isolated and screened against 3 prevalent strains of BLB pathogen Xanthomonas oryzae pv. oryzae (Xoo of which five antagonistic bacteria, i.e., Pseudomonas spp. E227, E233, Rh323, Serratia sp. Rh269 and Bacillus sp. Rh219 showed antagonistic potential (zone of inhibition 1-19 mm. Production of siderophores was found to be the common biocontrol determinant and all the strains solubilized inorganic phosphate (82-116 μg mL-1 and produced indole acetic acid (0.48-1.85 mg L-1 in vitro. All antagonistic bacteria were non-pathogenic to rice, and their co-inoculation significantly improved plant health in terms of reduced diseased leaf area (80%, improved shoot length (31%, root length (41% and plant dry weight (60% as compared to infected control plants. Furthermore, under pathogen pressure, bacterial inoculation resulted in increased activity of defense related enzymes including phenylalanine ammonia-lyase and polyphenol oxidase, along with 86% increase in peroxidase and 53% increase in catalase enzyme activities in plants inoculated with Pseudomonas sp. Rh323 as well as co-inoculated plants. Bacterial strains showed good colonization potential in the rice rhizosphere up to 21 days after seed inoculation. Application of bacterial consortia in the field resulted in an increase of 31% in grain yield and 10% in straw yield over non-inoculated plots. Although, yield increase was statistically non-significant but was accomplished with overall saving of 20% chemical fertilizers. The study showed that Pseudomonas sp. Rh323 can be used to develop dual-purpose inoculum which can serve not only to suppress BLB but also to promote plant growth in rice.

  3. Meta-transcriptomics indicates biotic cross-tolerance in willow trees cultivated on petroleum hydrocarbon contaminated soil.

    Science.gov (United States)

    Gonzalez, Emmanuel; Brereton, Nicholas J B; Marleau, Julie; Guidi Nissim, Werther; Labrecque, Michel; Pitre, Frederic E; Joly, Simon

    2015-10-12

    High concentrations of petroleum hydrocarbon (PHC) pollution can be hazardous to human health and leave soils incapable of supporting agricultural crops. A cheap solution, which can help restore biodiversity and bring land back to productivity, is cultivation of high biomass yielding willow trees. However, the genetic mechanisms which allow these fast-growing trees to tolerate PHCs are as yet unclear. Salix purpurea 'Fish Creek' trees were pot-grown in soil from a former petroleum refinery, either lacking or enriched with C10-C50 PHCs. De novo assembled transcriptomes were compared between tree organs and impartially annotated without a priori constraint to any organism. Over 45% of differentially expressed genes originated from foreign organisms, the majority from the two-spotted spidermite, Tetranychus urticae. Over 99% of T. urticae transcripts were differentially expressed with greater abundance in non-contaminated trees. Plant transcripts involved in the polypropanoid pathway, including phenylalanine ammonia-lyase (PAL), had greater expression in contaminated trees whereas most resistance genes showed higher expression in non-contaminated trees. The impartial approach to annotation of the de novo transcriptomes, allowing for the possibility for multiple species identification, was essential for interpretation of the crop's response treatment. The meta-transcriptomic pattern of expression suggests a cross-tolerance mechanism whereby abiotic stress resistance systems provide improved biotic resistance. These findings highlight a valuable but complex biotic and abiotic stress response to real-world, multidimensional contamination which could, in part, help explain why crops such as willow can produce uniquely high biomass yields on challenging marginal land.

  4. Uncoupled defense gene expression and antimicrobial alkaloid accumulation in elicited opium poppy cell cultures.

    Science.gov (United States)

    Facchini, P J; Johnson, A G; Poupart, J; de Luca, V

    1996-01-01

    Treatment of opium poppy (Papaver somniferum L.) cell cultures with autoclaved mycelial homogenates of Botrytis sp. resulted in the accumulation of sanguinarine. Elicitor treatment also caused a rapid and transient induction in the activity of tyrosine/dopa decarboxylase (TYDC, EC 4.1.1.25), which catalyzes the conversion of L-tyrosine and L-dopa to tyramine and dopamine, respectively, the first steps in sanguinarine biosynthesis. TYDC genes were differentially expressed in response to elicitor treatment. TYDC1-like mRNA levels were induced rapidly but declined to near baseline levels within 5 h. In contrast, TYDC2-like transcript levels increased more slowly but were sustained for an extended period. Induction of TYDC mRNAs preceded that of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) mRNAs. An elicitor preparation from Pythium aphanidermatum was less effective in the induction of TYDC mRNA levels and alkaloid accumulation; however, both elicitors equally induced accumulation of PAL transcripts. In contrast, treatment with methyl jasmonate resulted in an induction of TYDC but not PAL mRNAs. The calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide and the protein kinase inhibitor staurosporine partially blocked the fungal elicitor-induced accumulation of sanguinarine. However, only staurosporine and okadaic acid, an inhibitor of protein phosphatases 1 and 2A, blocked the induction of TYDC1-like transcript levels, but they did not block the induction of TYDC2-like or PAL transcript levels. These data suggest that activation mechanisms for PAL, TYDC, and some later sanguinarine biosynthetic enzymes are uncoupled. PMID:8754678

  5. Ammonium-related metabolic changes affect somatic embryogenesis in pumpkin (Cucurbita pepo L.).

    Science.gov (United States)

    Mihaljević, Snježana; Radić, Sandra; Bauer, Nataša; Garić, Rade; Mihaljević, Branka; Horvat, Gordana; Leljak-Levanić, Dunja; Jelaska, Sibila

    2011-11-01

    Somatic embryogenesis in pumpkin can be induced on auxin-containing medium and also on hormone-free medium containing 1mM ammonium (NH(4)(+)) as the sole source of nitrogen. Growth of NH(4)(+)-induced embryogenic tissue was slow and caused considerable acidification of the culture medium. Small spherical cells with dense cytoplasma formed proembryogenic cell clusters that could not develop into late stage embryos. Buffering of NH(4)(+) medium with 25mM 2-(N-morpholino)-ethane-sulfonic acid enhanced tissue proliferation, but no further differentiation was observed. Later stage embryos developed only after re-supply of nitrogen in form of nitrate or l-glutamine. Effects of nitrogen status and pH of culture media on ammonium assimilation were analyzed by following the activity of glutamine synthetase (GS) in relation to phenylalanine ammonia-lyase (PAL). Increased activity of GS and PAL in NH(4)(+) induced tissue coincided with significantly higher activity of stress-related enzymes superoxide dismutase (SOD) and soluble peroxidase (POD), indicating oxidative stress response of embryogenic tissue to NH(4)(+) as the sole source of nitrogen. In addition, considerable increase was observed in callose accumulation and esterase activity, the early markers of somatic embryogenesis. Activity of stress-related enzymes decreased after the re-supply of nitrate (20mM) or Gln (10mM) in combination with NH(4)(+) (1mM), which subsequently triggered globular embryo development. Together, these results suggest that stress responses, as affected by nitrogen supply, contribute to the regulation of embryogenic competence in pumpkin. Copyright © 2011 Elsevier GmbH. All rights reserved.

  6. Characterization of promoter of EgPAL1, a novel PAL gene from the oil palm Elaeis guineensis Jacq.

    Science.gov (United States)

    Yusuf, Chong Yu Lok; Abdullah, Janna Ong; Shaharuddin, Noor Azmi; Abu Seman, Idris; Abdullah, Mohd Puad

    2018-02-01

    The oil palm EgPAL1 gene promoter and its regulatory region were functional as a promoter in the heterologous system of Arabidopsis according to the cis-acting elements present in that region. The promoter was developmentally regulated, vascular tissue specific and responsive to water stress agents. Phenylalanine ammonia lyase (PAL, EC 4.3.1.24) is the key enzyme of the phenylpropanoid pathway which plays important roles in plant development and adaptation. To date, there is no report on the study of PAL from oil palm (Elaeis guineensis), an economically important oil crop. In this study, the 5' regulatory sequence of a highly divergent oil palm PAL gene (EgPAL1) was isolated and fused with GUS in Arabidopsis to create two transgenic plants carrying the minimal promoter with (2302 bp) and without its regulatory elements (139 bp). The regulatory sequence contained cis-acting elements known to be important for plant development and stress response including the AC-II element for lignin biosynthesis and several stress responsive elements. The promoter and its regulatory region were fully functional in Arabidopsis. Its activities were characterised by two common fundamental features of PAL which are responsive to plant internal developmental programme and external factors. The promoter was developmentally regulated in certain organs; highly active in young organs but less active or inactive in mature organs. The presence of the AC elements and global activity of the EgPAL1 promoter in all organs resembled the property of lignin-related genes. The existence of the MBS element and enhancement of the promoter activity by PEG reflected the behaviour of drought-responsive genes. Our findings provide a platform for evaluating oil palm gene promoters in the heterologous system of Arabidopsis and give insights into the activities of EgPAL1 promoter in oil palm.

  7. Salicylic acid alleviates aluminum toxicity in soybean roots through modulation of reactive oxygen species metabolism

    Science.gov (United States)

    Liu, Ning; Song, Fengbin; Zhu, Xiancan; You, Jiangfeng; Yang, Zhenming; Li, Xiangnan

    2017-11-01

    As an important signal molecule, salicylic acid (SA) improves plant tolerance to aluminum (Al) stress. The objective of this study was to investigate the effects of exogenous SA application on the dynamics of endogenous SA and reactive oxygen species in soybean (Glycine max L.) exposed to Al stress. The roots of soybean seedlings were exposed to a combination of AlCl3 (30 μM) and SA (10 μM)/PAC (100 μM, paclobutrazol, SA biosynthesis inhibitor) for 3, 6, 9 and 12 h. Al stress induced an increase in endogenous SA concentration in a time-dependent manner, also verified by the up-regulated expression of GmNPR1, an SA-responsive gene. Al stress increased the activities of phenylalanine ammonia-lyase (PAL) and benzoic acid 2-hydroxylase (BA2H), and the contents of SA, O2- and malondialdehyde (MDA) in the root apex. The application of exogenous SA increased PAL and BA2H, and reduced O2- and MDA contents in soybean roots under Al stress. PAC inhibited the SA induced increase in BA2H activity. In addition, the SA application resulted in a rapid increase in hydrogen peroxide (H2O2) concentration under Al stress, followed by a sharp decrease. Compared with the plants exposed to Al alone, Al+SA plants possessed higher activities of superoxide dismutase, peroxidase and ascorbate peroxidase, and lower catalase activity, indicating that SA alleviated Al-induced oxidative damage. These results suggested that PAL and BA2H were involved in Al-induced SA production and showed that SA alleviated the adverse effects of Al toxicity by modulating the cellular H2O2 level and the antioxidant enzyme activities in the soybean root apex.

  8. Control of wilt and rot pathogens of tomato by antagonistic pink pigmented facultative methylotrophic Delftia lacustris and Bacillus spp.

    Directory of Open Access Journals (Sweden)

    Veeranan Janahiraman

    2016-11-01

    Full Text Available The studies on the biocontrol potential of pink pigmented facultative methylotrophic (PPFM bacteria other than the genus Methylobacterium are scarce. In the present study, we report three facultative methylotrophic isolates; PPO-1, PPT-1 and PPB-1, respectively identified as Delftia lacustris, Bacillus subtilis and Bacillus cereus by 16S rRNA gene sequence analysis. Hemolytic activity was tested to investigate the potential pathogenicity of isolates to plants and humans, the results indicates that the isolates PPO-1, PPT-1 and PPB-1 are not pathogenic strains. Under in vitro conditions, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 showed direct antagonistic effect by inhibiting the mycelial growth of fungal pathogens; Fusarium oxysporum f. sp. lycopersici (2.15, 2.05 and 1.95 cm, Sclerotium rolfsii (2.14, 2.04 and1.94 cm, Pythium ultimum (2.12, 2.02 and 1.92cm, and Rhizoctonia solani (2.18, 2.08 and 1.98 cm and also produced volatile inhibitory compounds. Under plant growth chamber condition methylotrophic bacterial isolates; D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 significantly reduced the disease incidence of tomato. Under greenhouse condition, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 inoculated tomato plants, when challenged with F. oxysporum f. sp. lycopersici, S. rolfsii, P. ultimum and R. solani, increased the pathogenesis related proteins (β-1, 3-glucanase and chitinase and defense enzymes (phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, and catalase on day 5 after inoculation. In the current study, we first report the facultative methylotrophy in pink pigmented Delftia lacustris, B. subtilis, and B. cereus and their antagonistic potential against fungal pathogens. Direct antagonistic and ISR effects of these isolates against fungal pathogens of tomato evidenced their possible use as a biocontrol agent.

  9. Development of an Amperometric Biosensor Platform for the Combined Determination of L-Malic, Fumaric, and L-Aspartic Acid.

    Science.gov (United States)

    Röhlen, Désirée L; Pilas, Johanna; Schöning, Michael J; Selmer, Thorsten

    2017-10-01

    Three amperometric biosensors have been developed for the detection of L-malic acid, fumaric acid, and L -aspartic acid, all based on the combination of a malate-specific dehydrogenase (MDH, EC 1.1.1.37) and diaphorase (DIA, EC 1.8.1.4). The stepwise expansion of the malate platform with the enzymes fumarate hydratase (FH, EC 4.2.1.2) and aspartate ammonia-lyase (ASPA, EC 4.3.1.1) resulted in multi-enzyme reaction cascades and, thus, augmentation of the substrate spectrum of the sensors. Electrochemical measurements were carried out in presence of the cofactor β-nicotinamide adenine dinucleotide (NAD + ) and the redox mediator hexacyanoferrate (III) (HCFIII). The amperometric detection is mediated by oxidation of hexacyanoferrate (II) (HCFII) at an applied potential of + 0.3 V vs. Ag/AgCl. For each biosensor, optimum working conditions were defined by adjustment of cofactor concentrations, buffer pH, and immobilization procedure. Under these improved conditions, amperometric responses were linear up to 3.0 mM for L-malate and fumarate, respectively, with a corresponding sensitivity of 0.7 μA mM -1 (L-malate biosensor) and 0.4 μA mM -1 (fumarate biosensor). The L-aspartate detection system displayed a linear range of 1.0-10.0 mM with a sensitivity of 0.09 μA mM -1 . The sensor characteristics suggest that the developed platform provides a promising method for the detection and differentiation of the three substrates.

  10. Physiochemical and Phytochemical Properties of Wax Apple (Syzygium samarangense [Blume] Merrill & L. M. Perry var. Jambu Madu as Affected by Growth Regulator Application

    Directory of Open Access Journals (Sweden)

    Mohammad Moneruzzaman Khandaker

    2012-01-01

    Full Text Available This study represents the first paper of the effects of growth regulators on the physiochemical and phytochemical properties of the wax apple fruit, a widely cultivated fruit tree in southeast Asia. Net photosynthesis, sucrose phosphate synthase (SPS activity, peel color, fruit firmness, juice content, pH value, total soluble solids (TSSs, and the sugar acid ratio were all significantly increased in growth regulators (PGRs treated fruits. The application of gibberellin (GA3, naphthalene acetic acid (NAA, and 2,4-dichlorophenoxy acetic acid (2,4-D significantly reduced titratable acidity and increased total sugar and carbohydrate content compared to the control. The 50 mg/L GA3, 10 mg/L NAA, and 5 mg/L 2,4-D treatments produced the greatest increases in phenol and flavonoid content; vitamin C content was also higher for these treatments. PGR treatment significantly affected chlorophyll, anthocyanin, and carotene content and produced higher phenylalanine ammonia lyase (PAL and antioxidant activity levels. There was a positive correlation between peel color and TSS and antioxidant activity and both phenol and flavonoid content and PAL activity and anthocyanin formation. A taste panel assessment was also performed, and the highest scores were given to fruits that had been treated with GA3 or auxin. The study showed that application of 50 mg/L GA3, 10 mg/L NAA, and 5 mg/L 2,4-D once a week from bud development to fruit maturation increased the physiochemical and phytochemical properties of wax apple fruits.

  11. 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.

  12. 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.

  13. Antioxidant Enzyme Activities and Secondary Metabolite Profiling of Oil Palm Seedlings Treated with Combination of NPK Fertilizers Infected with Ganoderma boninense

    Science.gov (United States)

    Mohidin, Hasmah; Idris, Abu Seman; Fariz, A.; Abiri, Rambod; Taheri, Sima; Moradpoor, Mehdi

    2018-01-01

    Oil palm (Elaeis guineensis Jacq) is one of the major sources of edible oil. Reducing the effect of Ganoderma, main cause of basal stem rot (BSR) on oil palm, is the main propose of this study. Understanding the oil palm defense mechanism against Ganoderma infection through monitoring changes in the secondary metabolite compounds levels before/after infection by Ganoderma under different fertilizing treatment is required. Oil palm requires macro- and microelements for growth and yield. Manipulating the nutrient for oil palm is a method to control the disease. The 3-4-month-old oil palm seedlings were given different macronutrient treatments to evaluate induction of defense related enzymes and production of secondary metabolite compounds in response to G. boninense inoculation. The observed trend of changes in the infected and uninfected seedlings was a slightly higher activity for β-1,3-glucanases, chitinase, peroxidase, and phenylalanine ammonia-lyase during the process of pathogenesis. It was found that PR proteins gave positive response to the interaction between oil palm seedlings and Ganoderma infection. Although the responses were activated systematically, they were short-lasting as the changes in enzymes activities appeared before the occurrence of visible symptoms. Effect of different nutrients doses was obviously observed among the results of the secondary metabolite compounds. Many identified/unidentified metabolite compounds were presented, of which some were involved in plant cell defense mechanism against pathogens, mostly belonging to alkaloids with bitter-tasting nitrogenous-compounds, and some had the potential to be used as new markers to detect basal stem rot at the initial step of disease. PMID:29721500

  14. Nitrogen Limited Red and Green Leaf Lettuce Accumulate Flavonoid Glycosides, Caffeic Acid Derivatives, and Sucrose while Losing Chlorophylls, Β-Carotene and Xanthophylls.

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    Christine Becker

    Full Text Available Reduction of nitrogen application in crop production is desirable for ecological and health-related reasons. Interestingly, nitrogen deficiency can lead to enhanced concentrations of polyphenols in plants. The reason for this is still under discussion. The plants' response to low nitrogen concentration can interact with other factors, for example radiation intensity. We cultivated red and green leaf lettuce hydroponically in a Mediterranean greenhouse, supplying three different levels of nitrogen (12 mM, 3 mM, 0.75 mM, either in full or reduced (-50% radiation intensity. In both red and green lettuce, we found clear effects of the nitrogen treatments on growth characteristics, phenolic and photosynthetic compounds, nitrogen, nitrate and carbon concentration of the plants. Interestingly, the concentrations of all main flavonoid glycosides, caffeic acid derivatives, and sucrose increased with decreasing nitrogen concentration, whereas those of chlorophylls, β-carotene, neoxanthin, lactucaxanthin, all trans- and cis-violaxanthin decreased. The constitutive concentrations of polyphenols were lower in the green cultivar, but their relative increase was more pronounced than in the red cultivar. The constitutive concentrations of chlorophylls, β-carotene, neoxanthin, all trans- and cis-violaxanthin were similar in red and green lettuce and with decreasing nitrogen concentration they declined to a similar extent in both cultivars. We only detected little influence of the radiation treatments, e.g. on anthocyanin concentration, and hardly any interaction between radiation and nitrogen concentration. Our results imply a greater physiological plasticity of green compared to the red lettuce regarding its phenolic compounds. They support the photoprotection theory regarding anthocyanins as well as the theory that the deamination activity of phenylalanine ammonia-lyase drives phenylpropanoid synthesis.

  15. A horizontal gene transfer at the origin of phenylpropanoid metabolism: a key adaptation of plants to land

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    Gribaldo Simonetta

    2009-02-01

    Full Text Available Abstract Background The pioneering ancestor of land plants that conquered terrestrial habitats around 500 million years ago had to face dramatic stresses including UV radiation, desiccation, and microbial attack. This drove a number of adaptations, among which the emergence of the phenylpropanoid pathway was crucial, leading to essential compounds such as flavonoids and lignin. However, the origin of this specific land plant secondary metabolism has not been clarified. Results We have performed an extensive analysis of the taxonomic distribution and phylogeny of Phenylalanine Ammonia Lyase (PAL, which catalyses the first and essential step of the general phenylpropanoid pathway, leading from phenylalanine to p-Coumaric acid and p-Coumaroyl-CoA, the entry points of the flavonoids and lignin routes. We obtained robust evidence that the ancestor of land plants acquired a PAL via horizontal gene transfer (HGT during symbioses with soil bacteria and fungi that are known to have established very early during the first steps of land colonization. This horizontally acquired PAL represented then the basis for further development of the phenylpropanoid pathway and plant radiation on terrestrial environments. Conclusion Our results highlight a possible crucial role of HGT from soil bacteria in the path leading to land colonization by plants and their subsequent evolution. The few functional characterizations of sediment/soil bacterial PAL (production of secondary metabolites with powerful antimicrobial activity or production of pigments suggest that the initial advantage of this horizontally acquired PAL in the ancestor of land plants might have been either defense against an already developed microbial community and/or protection against UV. Reviewers This article was reviewed by Purificación López-García, Janet Siefert, and Eugene Koonin.

  16. Antioxidant Enzyme Activities and Secondary Metabolite Profiling of Oil Palm Seedlings Treated with Combination of NPK Fertilizers Infected with Ganoderma boninense.

    Science.gov (United States)

    Sahebi, Mahbod; Hanafi, Mohamed M; Mohidin, Hasmah; Rafii, M Y; Azizi, Parisa; Idris, Abu Seman; Fariz, A; Abiri, Rambod; Taheri, Sima; Moradpoor, Mehdi

    2018-01-01

    Oil palm ( Elaeis guineensis Jacq) is one of the major sources of edible oil. Reducing the effect of Ganoderma, main cause of basal stem rot (BSR) on oil palm, is the main propose of this study. Understanding the oil palm defense mechanism against Ganoderma infection through monitoring changes in the secondary metabolite compounds levels before/after infection by Ganoderma under different fertilizing treatment is required. Oil palm requires macro- and microelements for growth and yield. Manipulating the nutrient for oil palm is a method to control the disease. The 3-4-month-old oil palm seedlings were given different macronutrient treatments to evaluate induction of defense related enzymes and production of secondary metabolite compounds in response to G. boninense inoculation. The observed trend of changes in the infected and uninfected seedlings was a slightly higher activity for β -1,3-glucanases, chitinase, peroxidase, and phenylalanine ammonia-lyase during the process of pathogenesis. It was found that PR proteins gave positive response to the interaction between oil palm seedlings and Ganoderma infection. Although the responses were activated systematically, they were short-lasting as the changes in enzymes activities appeared before the occurrence of visible symptoms. Effect of different nutrients doses was obviously observed among the results of the secondary metabolite compounds. Many identified/unidentified metabolite compounds were presented, of which some were involved in plant cell defense mechanism against pathogens, mostly belonging to alkaloids with bitter-tasting nitrogenous-compounds, and some had the potential to be used as new markers to detect basal stem rot at the initial step of disease.

  17. Antioxidant Enzyme Activities and Secondary Metabolite Profiling of Oil Palm Seedlings Treated with Combination of NPK Fertilizers Infected with Ganoderma boninense

    Directory of Open Access Journals (Sweden)

    Mahbod Sahebi

    2018-01-01

    Full Text Available Oil palm (Elaeis guineensis Jacq is one of the major sources of edible oil. Reducing the effect of Ganoderma, main cause of basal stem rot (BSR on oil palm, is the main propose of this study. Understanding the oil palm defense mechanism against Ganoderma infection through monitoring changes in the secondary metabolite compounds levels before/after infection by Ganoderma under different fertilizing treatment is required. Oil palm requires macro- and microelements for growth and yield. Manipulating the nutrient for oil palm is a method to control the disease. The 3-4-month-old oil palm seedlings were given different macronutrient treatments to evaluate induction of defense related enzymes and production of secondary metabolite compounds in response to G. boninense inoculation. The observed trend of changes in the infected and uninfected seedlings was a slightly higher activity for β-1,3-glucanases, chitinase, peroxidase, and phenylalanine ammonia-lyase during the process of pathogenesis. It was found that PR proteins gave positive response to the interaction between oil palm seedlings and Ganoderma infection. Although the responses were activated systematically, they were short-lasting as the changes in enzymes activities appeared before the occurrence of visible symptoms. Effect of different nutrients doses was obviously observed among the results of the secondary metabolite compounds. Many identified/unidentified metabolite compounds were presented, of which some were involved in plant cell defense mechanism against pathogens, mostly belonging to alkaloids with bitter-tasting nitrogenous-compounds, and some had the potential to be used as new markers to detect basal stem rot at the initial step of disease.

  18. Fine-tuning of the flavonoid and monolignol pathways during apple early fruit development.

    Science.gov (United States)

    Baldi, Paolo; Moser, Mirko; Brilli, Matteo; Vrhovsek, Urska; Pindo, Massimo; Si-Ammour, Azeddine

    2017-05-01

    A coordinated regulation of different branches of the flavonoid pathway was highlighted that may contribute to elucidate the role of this important class of compounds during the early stages of apple fruit development. Apple (Malus × domestica Borkh.) is an economically important fruit appreciated for its organoleptic characteristics and its benefits for human health. The first stages after fruit set represent a very important and still poorly characterized developmental process. To enable the profiling of genes involved in apple early fruit development, we combined the suppression subtractive hybridization (SSH) protocol to next-generation sequencing. We identified and characterized genes induced and repressed during fruit development in the apple cultivar 'Golden Delicious'. Our results showed an opposite regulation of genes coding for enzymes belonging to flavonoid and monolignol pathways, with a strong induction of the former and a simultaneous repression of the latter. Two isoforms of phenylalanine ammonia-lyase and 4-coumarate:CoA ligase, key enzymes located at the branching point between flavonoid and monolignol pathways, showed opposite expression patterns during the period in analysis, suggesting a possible regulation mechanism. A targeted metabolomic analysis supported the SSH results and revealed an accumulation of the monomers catechin and epicatechin as well as several forms of procyanidin oligomers in apple fruitlets starting early after anthesis, together with a decreased production of other classes of flavonoids such as some flavonols and the dihydrochalcone phlorizin. Moreover, gene expression and metabolites accumulation of 'Golden Delicious' were compared to a wild apple genotype of Manchurian crabapple (Malus mandshurica (Maxim.) Kom.). Significant differences in both gene expression and metabolites accumulation were found between the two genotypes.

  19. Effect of earthworms on growth, photosynthetic efficiency and metal uptake in Brassica juncea L. plants grown in cadmium-polluted soils.

    Science.gov (United States)

    Kaur, Parminder; Bali, Shagun; Sharma, Anket; Vig, Adarsh Pal; Bhardwaj, Renu

    2017-05-01

    The present study has been carried out to examine the role of earthworms in phytoremediation of Cd and its effect on growth, pigment content, expression of genes coding key enzymes of pigments, photosynthetic efficiency and osmoprotectants in Brassica juncea L. plants grown under cadmium (Cd) metal stress. The effect of different Cd concentrations (0.50, 0.75, 1.0, 1.25 mM) was studied in 30 and 60-day-old plants grown in soils containing earthworms. It was observed that earthworm inoculation showed stimulatory effect on phytoremediation capacity and Cd uptake has increased by 49% (in 30-day-old plants) and 35% (in 60-day-old plants) in shoots and 13.3% (in 30-day-old plants) and 10% (in 60-day-old plants) in roots in 30 and 60-day-old plants in Cd (1.25 mM) treatments. Plant growth parameters such as root and shoot length, relative water content and tolerance index were found to increase in the presence of earthworms. Recovery in photosynthetic pigments (chlorophyll and carotenoid) and gas exchange parameters, i.e. net photosynthetic rate (P n ), stomatal conductance (G s ), intercellular CO 2 concentration (C i ) and transpiration rate (E t ), was observed after earthworm's supplementation. Modulation in expression of key enzymes for pigment synthesis, i.e. chlorophyllase, phytoene synthase, chalcone synthase and phenylalanine ammonia lyase, was also observed. The results of our study revealed that earthworms help to mitigate the toxic effects produced by Cd on plant growth and photosynthetic efficiency along with enhanced phytoremediation capacity when co-inoculated with Cd in soil.

  20. 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

  1. Effects of Salicylic Acid on the Growth and Physiological Characteristics in Cyclocarya Paliurus Seedlings

    International Nuclear Information System (INIS)

    Xie, Y.; Guo, N.; Zhang, Y.; Liu, N.; Wang, T.; Yang, W.; Fang, S.

    2016-01-01

    Field studies were conducted to examine the effects of salicylic acid (SA) on the growth and physiological characteristics of Cyclocarya paliurus seedlings by spraying the foliage with 0.0 (control), 0.2, 1.0, and 2.0 mM salicylic acid (SA). Proper concentrations of SA improved the relative growth yield of seedling stems and the soluble protein and sugar content of the leaves. It also increased the content of secondary metabolites including triterpenoids, flavonoids, quercetin and kaempferol, mineral elements K, Ca, Mg, Mn, Fe and Cu. Moreover, it stimulated the activities of superoxide dismutase (SOD), peroxidase (POX) and phenylalanine ammonia lyase (PAL) in the leaves. The effects of SA on these indices were dose dependent. The relative growth of seedling stem diameter and quercetin content increased gradually with an increase in concentration of SA from 0.0-2.0 mM. A concentration of 0.2 mM was optimal to promote content of soluble protein, sugars, Ca, Mg, Mn, Fe, and Cu, and SOD activity and significantly increased by 38.6 percentage, 22.1 percentage, 17.7 percentage, 8.2 percentage, 20.3 percentage, 23.2 percentage, 15.6 percentage, and 52.4 percentage, respectively, as compared with the control (CK). However, the maximal increase in activities of PAL, POX, and content of triterpenoids, kaempferol, and flavonoids was attained at 1.0 mM treatment, which significantly increased by 76.5 percentage, 78.4 percentage, 76.4 percentage, 96.3 percentage, and 107.4 percentage, respectively, compared with CK. Correlation analysis revealed positive relationships between activities of PAL, POX and content of triterpenoids, quercetin, kaempferol, and flavonoids within a certain concentration range of SA. These results suggested that an appropriate concentration (0.2-1.0 mM) of SA was not only effective in the improvement of physiological function of C. paliurus, but also increased seedling resistance; additionally, it helped to stimulate the synthesis of medicinal

  2. Combined effect of water loss and wounding stress on gene activation of metabolic pathways associated with phenolic biosynthesis in carrot

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    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

  3. The effects of enhanced methionine synthesis on amino acid and anthocyanin content of potato tubers

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    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

  4. Gamma irradiation of medicinally important plants and the enhancement of secondary metabolite production.

    Science.gov (United States)

    Vardhan, P Vivek; Shukla, Lata I

    2017-09-01

    The profitable production of some important plant-based secondary metabolites (ginsenosides, saponins, camptothecin, shikonins etc.) in vitro by gamma irradiation is a current area of interest. We reviewed different types of secondary metabolites, their mode of synthesis and effect of γ-radiation on their yield for different plants, organs and in vitro cultures (callus, suspension, hairy root). Special effort has been made to review the biochemical mechanisms underlying the increase in secondary metabolites. A comparison of yield improvement with biotic and abiotic stresses was made. Phenolic compounds increase with γ-irradiation in whole plants/plant parts; psoralen content in the common herb babchi (Psoralea corylifolia) was increased as high as 32-fold with γ-irradiation of seeds at 20 kGy. The capsaicinoids, a phenolic compound increased about 10% with 10 kGy in paprika (Capsicum annum L.). The in vitro studies show all the three types of secondary metabolites are reported to increase with γ-irradiation. Stevioside, total phenolic and flavonoids content were slightly increased in 15 Gy-treated callus cultures of stevia (Stevia rebaudiana Bert.). In terpenoids, total saponin and ginsenosides content were increased 1.4- and 1.8-fold, respectively, with 100 Gy for wild ginseng (Panax ginseng Meyer) hairy root cultures. In alkaloids, camptothecin yield increased as high as 20-fold with 20 Gy in callus cultures of ghanera (Nothapodytes foetida). Shikonins increased up to 4-fold with 16 Gy in suspension cultures of purple gromwell (Lithospermum erythrorhizon S.). The enzymes associated with secondary metabolite production were increased with γ-irradiation of 20 Gy; namely, phenylalanine ammonia-lyase (PAL) for phenolics, chalcone synthase (CHS) for flavonoids, squalene synthase (SS), squalene epoxidase (SE) and oxidosqualene cyclases (OSC) for ginsenosides and PHB (p-hydroxylbenzoic acid) geranyl transferase for shikonins. An increase in secondary

  5. Phase 1 Trial of Subcutaneous rAvPAL-PEG in Subjects with Phenylketonuria

    Science.gov (United States)

    Longo, Nicola; Harding, Cary O.; Burton, Barbara K.; Grange, Dorothy K.; Vockley, Jerry; Wasserstein, Melissa; Rice, Gregory M.; Musson, Donald G.; Gu, Zhonghua; Sile, Saba

    2014-01-01

    Objective Phenylketonuria is an inherited disease caused by impaired activity of phenylalanine hydroxylase, the enzyme that converts phenylalanine to tyrosine, leading to accumulation of phenylalanine and subsequent neurocognitive dysfunction. A phenylalanine-restricted diet initiated early in life can ameliorate the toxic effects of phenylalanine. However, the diet is onerous and compliance is extremely difficult. Phenylalanine ammonia lyase (PAL) is a prokaryotic enzyme that converts phenylalanine to ammonia and trans-cinnamic acid. This Phase 1, multicenter clinical trial evaluated the safety, tolerability, pharmacokinetics and efficacy of rAvPAL-PEG (recombinant Anabaena variabilis PAL produced in E. coli conjugated with polyethylene glycol [PEG] to reduce immunogenicity) in reducing phenylalanine levels in subjects with phenylketonuria. Methods Single subcutaneous injections of rAvPAL-PEG in escalating doses (0·001, 0·003, 0·01, 0·03, and 0·1 mg/kg) were administered to 25 adults with phenylketonuria recruited from those attending metabolic clinics in North America whose blood phenylalanine concentrations were ≥600 μmol/L. Results The most frequently reported adverse events were injection-site reactions and dizziness. Reactions were self-limited without sequelae. During the trial, two subjects had adverse reactions to intramuscular (IM) medroxyprogesterone acetate, a drug containing polyethylene glycol as an excipient. Three subjects developed a generalized skin rash at the highest rAvPAL-PEG dose (0·1 mg/kg). Drug levels peaked ∼5 days after the injection. Treatment was effective in reducing blood phenylalanine in all five subjects receiving the highest dose (0·1 mg/kg, mean percent change of -58 from baseline), with a nadir ∼6 days after injection and inverse correlation between drug and phenylalanine concentrations in plasma. Phenylalanine concentrations returned to near-baseline levels ∼20 days after the single injection. Conclusions

  6. Lignin biosynthesis in wheat (Triticum aestivum L.): its response to waterlogging and association with hormonal levels.

    Science.gov (United States)

    Nguyen, Tran-Nguyen; Son, SeungHyun; Jordan, Mark C; Levin, David B; Ayele, Belay T

    2016-01-25

    Lignin is an important structural component of plant cell wall that confers mechanical strength and tolerance against biotic and abiotic stressors; however it affects the use of biomass such as wheat straw for some industrial applications such as biofuel production. Genetic alteration of lignin quantity and quality has been considered as a viable option to overcome this problem. However, the molecular mechanisms underlying lignin formation in wheat biomass has not been studied. Combining molecular and biochemical approaches, the present study investigated the transcriptional regulation of lignin biosynthesis in two wheat cultivars with varying lodging characteristics and also in response to waterlogging. It also examined the association of lignin level in tissues with that of plant hormones implicated in the control of lignin biosynthesis. Analysis of lignin biosynthesis in the two wheat cultivars revealed a close association of lodging resistance with internode lignin content and expression of 4-coumarate:CoA ligase1 (4CL1), p-coumarate 3-hydroxylase1 (C3H1), cinnamoyl-CoA reductase2 (CCR2), ferulate 5-hydroxylase2 (F5H2) and caffeic acid O-methyltransferase2 (COMT2), which are among the genes highly expressed in wheat tissues, implying the importance of these genes in mediating lignin deposition in wheat stem. Waterlogging of wheat plants reduced internode lignin content, and this effect is accompanied by transcriptional repression of three of the genes characterized as highly expressed in wheat internode including phenylalanine ammonia-lyase6 (PAL6), CCR2 and F5H2, and decreased activity of PAL. Expression of the other genes was, however, induced by waterlogging, suggesting their role in the synthesis of other phenylpropanoid-derived molecules with roles in stress responses. Moreover, difference in internode lignin content between cultivars or change in its level due to waterlogging is associated with the level of cytokinin. Lodging resistance, tolerance against

  7. 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.

  8. 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

  9. Evaluation of Borage Extracts As Potential Biostimulant Using a Phenomic, Agronomic, Physiological, and Biochemical Approach.

    Science.gov (United States)

    Bulgari, Roberta; Morgutti, Silvia; Cocetta, Giacomo; Negrini, Noemi; Farris, Stefano; Calcante, Aldo; Spinardi, Anna; Ferrari, Enrico; Mignani, Ilaria; Oberti, Roberto; Ferrante, Antonio

    2017-01-01

    Biostimulants are substances able to improve water and nutrient use efficiency and counteract stress factors by enhancing primary and secondary metabolism. Premise of the work was to exploit raw extracts from leaves (LE) or flowers (FE) of Borago officinalis L., to enhance yield and quality of Lactuca sativa 'Longifolia,' and to set up a protocol to assess their effects. To this aim, an integrated study on agronomic, physiological and biochemical aspects, including also a phenomic approach, has been adopted. Extracts were diluted to 1 or 10 mL L -1 , sprayed onto lettuce plants at the middle of the growing cycle and 1 day before harvest. Control plants were treated with water. Non-destructive analyses were conducted to assess the effect of extracts on biomass with an innovative imaging technique, and on leaf photosynthetic efficiency (chlorophyll a fluorescence and leaf gas exchanges). At harvest, the levels of ethylene, photosynthetic pigments, nitrate, and primary (sucrose and total sugars) and secondary (total phenols and flavonoids) metabolites, including the activity and levels of phenylalanine ammonia lyase (PAL) were assessed. Moreover, a preliminary study of the effects during postharvest was performed. Borage extracts enhanced the primary metabolism by increasing leaf pigments and photosynthetic activity. Plant fresh weight increased upon treatments with 10 mL L -1 doses, as correctly estimated by multi-view angles images. Chlorophyll a fluorescence data showed that FEs were able to increase the number of active reaction centers per cross section; a similar trend was observed for the performance index. Ethylene was three-fold lower in FEs treatments. Nitrate and sugar levels did not change in response to the different treatments. Total flavonoids and phenols, as well as the total protein levels, the in vitro PAL specific activity, and the levels of PAL-like polypeptides were increased by all borage extracts, with particular regard to FEs. FEs also proved

  10. Evolutionary convergence in the biosyntheses of the imidazole moieties of histidine and purines.

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    Alberto Vázquez-Salazar

    , as well as the internal cyclization of the Ala-Ser-Gly motif of some members of the ammonia-lyase and aminomutase families, that lead to the MIO cofactor. The diversity of imidazole-synthesizing pathways highlights the biological significance of this key chemical group, whose biosyntheses evolved independently several times.

  11. ETHEPHON AND CALCIUM CHLORIDE, A COMBINATION THAT IMPROVES SKIN COLOR OF ‘RUBI’ TABLE GRAPE

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    Joseane Scavroni

    2018-02-01

    Full Text Available ABSTRACT ‘Rubi’ table grape has wide acceptance of the consumer market due to its affordable price and attractive color as a function of the accumulation of anthocyanins. However, environmental conditions do not always favor the suitable accumulation of these pigments, resulting in commercial devaluation and nutritional depreciation of fruits. Thus, the present study aimed to investigate the effect of application of different ethephon concentrations, associated or not with CaCl2 application, on the skin color and quality of ‘Rubi’ grape berries. First, specific traits of berries treated with 0, 200, 400, 600, 800 mg L-1 ethephon associated with 1.5% CaCl2 solution were evaluated and pH, titratable acidity (TA, soluble solids (SS, berry firmness, total and reducing soluble sugars, and anthocyanin and flavonol levels were analyzed. This first stage of evaluation revealed no changes in total sugar levels, firmness, SS, TA, SS/TA ratio, and flavonol levels, while changes were detected regarding reducing sugar and anthocyanin levels. Thus, in the second stage, the following variables were evaluated: SS, TA, reducing sugar levels, anthocyanin levels, phenylalanine ammonia lyase (PAL and glutathione S-transferase (GST activity of ‘Rubi’ grape berries treated with 0, 200, 400, 600, 800 mg L-1 ethephon, associated or not with 1.5% CaCl2 solution. The results of the present study indicate that ethephon associated with CaCl2 can contribute to improve the post-harvest quality of ‘Rubi’ grape, since this association increased the accumulation of anthocyanins due to the higher activity of PAL and GST, related to biosynthesis and storage of antocyanins, respectively, and increased the levels of reducing sugars (at low ethephon concentrations, not changing other quality aspects. Therefore, a single ethephon application from 200 mg L-1 associated with the application of 1.5% CaCl2 at the final ripening stage, when bunches present from 30 to 50

  12. Development and characterization of an oat TILLING-population and identification of mutations in lignin and β-glucan biosynthesis genes

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    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

  13. Evaluation of Borage Extracts As Potential Biostimulant Using a Phenomic, Agronomic, Physiological, and Biochemical Approach

    Directory of Open Access Journals (Sweden)

    Roberta Bulgari

    2017-06-01

    Full Text Available Biostimulants are substances able to improve water and nutrient use efficiency and counteract stress factors by enhancing primary and secondary metabolism. Premise of the work was to exploit raw extracts from leaves (LE or flowers (FE of Borago officinalis L., to enhance yield and quality of Lactuca sativa ‘Longifolia,’ and to set up a protocol to assess their effects. To this aim, an integrated study on agronomic, physiological and biochemical aspects, including also a phenomic approach, has been adopted. Extracts were diluted to 1 or 10 mL L–1, sprayed onto lettuce plants at the middle of the growing cycle and 1 day before harvest. Control plants were treated with water. Non-destructive analyses were conducted to assess the effect of extracts on biomass with an innovative imaging technique, and on leaf photosynthetic efficiency (chlorophyll a fluorescence and leaf gas exchanges. At harvest, the levels of ethylene, photosynthetic pigments, nitrate, and primary (sucrose and total sugars and secondary (total phenols and flavonoids metabolites, including the activity and levels of phenylalanine ammonia lyase (PAL were assessed. Moreover, a preliminary study of the effects during postharvest was performed. Borage extracts enhanced the primary metabolism by increasing leaf pigments and photosynthetic activity. Plant fresh weight increased upon treatments with 10 mL L–1 doses, as correctly estimated by multi-view angles images. Chlorophyll a fluorescence data showed that FEs were able to increase the number of active reaction centers per cross section; a similar trend was observed for the performance index. Ethylene was three-fold lower in FEs treatments. Nitrate and sugar levels did not change in response to the different treatments. Total flavonoids and phenols, as well as the total protein levels, the in vitro PAL specific activity, and the levels of PAL-like polypeptides were increased by all borage extracts, with particular regard to FEs

  14. Changes in polyphenol profile of dried apricots containing SO2 at various concentrations during storage.

    Science.gov (United States)

    Altındağ, Melek; Türkyılmaz, Meltem; Özkan, Mehmet

    2018-05-01

    Changes in polyphenols have important effects on the quality (especially color) and health benefits of dried apricots. SO 2 concentration, storage and the activities of polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) were factors which had significant effects on polyphenols. Polyphenol profile and activities of PPO and PAL in sulfured dried apricots (SDAs, 0, 451, 832, 2112 and 3241 mg SO 2 kg -1 ) were monitored during storage at 4, 20 and 30 °C for 379 days for the first time. Even the lowest SO 2 concentration (451 mg kg -1 ) was sufficient to inactivate PPO during the entire storage period. However, while SO 2 led to the increase in PAL activity of the samples (r = 0.767) before storage, PAL activities of SDAs decreased during storage. After 90 days of storage, PAL activity was determined in only non-sulfured dried apricots (NSDAs) and dried apricots containing 451 mg SO 2 kg -1 . Although the major polyphenol in NSDAs was epicatechin (611.4 mg kg -1 ), that in SDAs was chlorogenic acid (455-1508 mg kg -1 ), followed by epicatechin (0-426.8 mg kg -1 ), rutin (148.9-477.3 mg kg -1 ), ferulic acid (23.3-55.3 mg kg -1 ) and gallic acid (2.4-43.6 mg kg -1 ). After storage at 30 °C for 379 days, the major polyphenol in SDAs was gallic acid (706-2324 mg kg -1 ). However, the major polyphenol in NSDAs did not change after storage. The highest total polyphenol content was detected in SDAs containing 2112 mg SO 2 kg -1 and stored at 30 °C. To produce dried apricots having high polyphenol content, ∼2000 mg SO 2 kg -1 should be used. Low storage temperature (<30 °C) was not necessary for the protection of polyphenols. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  15. 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 < 0.05) causing considerable oxidative stress in G. dura. This further led to lipid peroxidation and degradation of the pigments Chl a and 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. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For

  16. Salinity Stress Is Beneficial to the Accumulation of Chlorogenic Acids in Honeysuckle (Lonicera japonica Thunb.).

    Science.gov (United States)

    Yan, Kun; Cui, Mingxing; Zhao, Shijie; Chen, Xiaobing; Tang, Xiaoli

    2016-01-01

    Honeysuckle ( Lonicera japonica Thunb.) is a traditional medicinal plant in China that is particularly rich in chlorogenic acids, which are phenolic compounds with various medicinal properties. This study aimed to examine the effects of salinity stress on accumulation of chlorogenic acids in honeysuckle, through hydroponic experiments and field trials, and to examine the mechanisms underlying the effects. NaCl stress stimulated the transcription of genes encoding key enzymes in the synthesis of chlorogenic acids in leaves; accordingly, the concentrations of chlorogenic acids in leaves were significantly increased under NaCl stress, as was antioxidant activity. Specifically, the total concentration of leaf chlorogenic acids was increased by 145.74 and 50.34% after 30 days of 150 and 300 mM NaCl stress, respectively. Similarly, the concentrations of chlorogenic acids were higher in the leaves of plants in saline, compared with non-saline, plots, with increases in total concentrations of chlorogenic acids of 56.05 and 105.29% in October 2014 and 2015, respectively. Despite leaf biomass reduction, absolute amounts of chlorogenic acids per plant and phenylalanine ammonia-lyase (PAL) activity were significantly increased by soil salinity, confirming that the accumulation of chlorogenic acids in leaves was a result of stimulation of their synthesis under salinity stress. Soil salinity also led to elevated chlorogenic acid concentrations in honeysuckle flower buds, with significant increases in total chlorogenic acids concentration of 22.42 and 25.14% in May 2014 and 2015, respectively. Consistent with biomass reduction, the absolute amounts of chlorogenic acid per plant declined in flower buds of plants exposed to elevated soil salinity, with no significant change in PAL activity. Thus, salinity-induced chlorogenic acid accumulation in flower buds depended on an amplification effect of growth reduction. In conclusion, salinity stress improved the medicinal quality of

  17. Salinity Stress is Beneficial to the Accumulation of Chlorogenic Acids in Honeysuckle (Lonicera japonica Thunb.

    Directory of Open Access Journals (Sweden)

    Kun Yan

    2016-10-01

    Full Text Available Abstract Honeysuckle (Lonicera japonica Thunb. is a traditional medicinal plant in China that is particularly rich in chlorogenic acids, which are phenolic compounds with various medicinal properties. This study aimed to examine the effects of salinity stress on accumulation of chlorogenic acids in honeysuckle, through hydroponic experiments and field trials, and to examine the mechanisms underlying the effects. NaCl stress stimulated the transcription of genes encoding key enzymes in the synthesis of chlorogenic acids in leaves; accordingly, the concentrations of chlorogenic acids in leaves were significantly increased under NaCl stress, as was antioxidant activity. Specifically, the total concentration of leaf chlorogenic acids was increased by 145.74% and 50.34% after 30 days of 150 and 300 mM NaCl stress, respectively. Similarly, the concentrations of chlorogenic acids were higher in the leaves of plants in saline, compared with non-saline, plots, with increases in total concentrations of chlorogenic acids of 56.05% and 105.29% in October 2014 and 2015, respectively. Despite leaf biomass reduction, absolute amounts of chlorogenic acids per plant and phenylalanine ammonia-lyase (PAL activity were significantly increased by soil salinity, confirming that the accumulation of chlorogenic acids in leaves was a result of stimulation of their synthesis under salinity stress. Soil salinity also led to elevated chlorogenic acid concentrations in honeysuckle flower buds, with significant increases in total chlorogenic acids concentration of 22.42% and 25.14% in May 2014 and 2015, respectively. Consistent with biomass reduction, the absolute amounts of chlorogenic acid per plant declined in flower buds of plants exposed to elevated soil salinity, with no significant change in PAL activity. Thus, salinity-induced chlorogenic acid accumulation in flower buds depended on an amplification effect of growth reduction. In conclusion, salinity stress improves

  18. Exploiting members of the BAHD acyltransferase family to synthesize multiple hydroxycinnamate and benzoate conjugates in yeast

    Energy Technology Data Exchange (ETDEWEB)

    Eudes, Aymerick [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mouille, Maxence [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Robinson, David S. [Joint BioEnergy Institute, Emeryville, CA (United States); Benites, Veronica T. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); San Francisco State Univ., San Francisco, CA (United States); Wang, George [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Roux, Lucien [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland); Tsai, Yi-Lin [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Baidoo, Edward E. K. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chiu, Tsan-Yu [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Heazlewood, Joshua L. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); The Univ. of Melbourne, Melbourne, VIC (Australia); Scheller, Henrik V. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mukhopadhyay, Aindrila [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Keasling, Jay D. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Technical Univ. of Denmark, Horsholm (Denmark); Deutsch, Samuel [Joint BioEnergy Institute, Emeryville, CA (United States); Loqué, Dominique [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. Claude Bernard Lyon 1, Villeurbanne (France)

    2016-11-21

    . Similarly, we achieved for the first time the microbial production of polyamine hydroxycinnamate amides; monolignol, malate and fatty alcohol hydroxycinnamate esters; tropane alkaloids; and benzoate/caffeate alcohol esters. In some instances, the additional expression of Flavobacterium johnsoniae tyrosine ammonia-lyase (FjTAL) allowed the synthesis of p-coumarate conjugates and eliminated the need to supplement the culture media with 4-hydroxycinnamate. In conclusion, we demonstrate in this study the effectiveness of expressing members of the plant BAHD acyltransferase family in yeast for the synthesis of numerous valuable hydroxycinnamate and benzoate conjugates.

  19. Synthesis of avenanthramides using engineered Escherichia coli.

    Science.gov (United States)

    Lee, Su Jin; Sim, Geun Young; Kang, Hyunook; Yeo, Won Seok; Kim, Bong-Gyu; Ahn, Joong-Hoon

    2018-03-22

    Hydroxycinnamoyl anthranilates, also known as avenanthramides (avns), are a group of phenolic alkaloids with anti-inflammatory, antioxidant, anti-itch, anti-irritant, and antiatherogenic activities. Some avenanthramides (avn A-H and avn K) are conjugates of hydroxycinnamic acids (HC), including p-coumaric acid, caffeic acid, and ferulic acid, and anthranilate derivatives, including anthranilate, 4-hydroxyanthranilate, and 5-hydroxyanthranilate. Avns are primarily found in oat grain, in which they were originally designated as phytoalexins. Knowledge of the avns biosynthesis pathway has now made it possible to synthesize avns through a genetic engineering strategy, which would help to further elucidate their properties and exploit their beneficial biological activities. The aim of the present study was to synthesize natural avns in Escherichia coli to serve as a valuable resource. We synthesized nine avns in E. coli. We first synthesized avn D from glucose in E. coli harboring tyrosine ammonia lyase (TAL), 4-coumarate:coenzyme A ligase (4CL), anthranilate N-hydroxycinnamoyl/benzoyltransferase (HCBT), and anthranilate synthase (trpEG). A trpD deletion mutant was used to increase the amount of anthranilate in E. coli. After optimizing the incubation temperature and cell density, approximately 317.2 mg/L of avn D was synthesized. Avn E and avn F were then synthesized from avn D, using either E. coli harboring HpaBC and SOMT9 or E. coli harboring HapBC alone, respectively. Avn A and avn G were synthesized by feeding 5-hydroxyanthranilate or 4-hydroxyanthranilate to E. coli harboring TAL, 4CL, and HCBT. Avn B, avn C, avn H, and avn K were synthesized from avn A or avn G, using the same approach employed for the synthesis of avn E and avn F from avn D. Using different HCs, nine avns were synthesized, three of which (avn D, avn E, and avn F) were synthesized from glucose in E. coli. These diverse avns provide a strategy to synthesize both natural and unnatural avns

  20. Genomics reveals traces of fungal phenylpropanoid-flavonoid metabolic pathway in the f ilamentous fungus Aspergillus oryzae.

    Science.gov (United States)

    Juvvadi, Praveen Rao; Seshime, Yasuyo; Kitamoto, Katsuhiko

    2005-12-01

    ., phenylalanine ammonia-lyase, cinnamic acid hydroxylase and p-coumarate CoA ligase) in the A. oryzae genome undoubtedly prove the extent of its metabolic diversity. Since many of these genes have not been identified earlier, knowledge on their corresponding products or activities remain undeciphered. In future, it is anticipated that these enzymes may be reasonable targets for metabolic engineering in fungi to produce agriculturally and nutritionally important metabolites.

  1. Glycosylation-mediated phenylpropanoid partitioning in Populus tremuloides cell cultures

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    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

  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. 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

  4. Quantitative changes in proteins responsible for flavonoid and anthocyanin biosynthesis in strawberry fruit at different ripening stages: A targeted quantitative proteomic investigation employing multiple reaction monitoring.

    Science.gov (United States)

    Song, Jun; Du, Lina; Li, Li; Kalt, Wilhelmina; Palmer, Leslie Campbell; Fillmore, Sherry; Zhang, Ying; Zhang, ZhaoQi; Li, XiHong

    2015-06-03

    To better understand the regulation of flavonoid and anthocyanin biosynthesis, a targeted quantitative proteomic investigation employing LC-MS with multiple reaction monitoring was conducted on two strawberry cultivars at three ripening stages. This quantitative proteomic workflow was improved through an OFFGEL electrophoresis to fractionate peptides from total protein digests. A total of 154 peptide transitions from 47 peptides covering 21 proteins and isoforms related to anthocyanin biosynthesis were investigated. The normalized protein abundance, which was measured using isotopically-labeled standards, was significantly changed concurrently with increased anthocyanin content and advanced fruit maturity. The protein abundance of phenylalanine ammonia-lyase; anthocyanidin synthase, chalcone isomerase; flavanone 3-hydroxylase; dihydroflavonol 4-reductase, UDP-glucose:flavonoid-3-O-glucosyltransferase, cytochrome c and cytochrome C oxidase subunit 2, was all significantly increased in fruit of more advanced ripeness. An interaction between cultivar and maturity was also shown with respect to chalcone isomerase. The good correlation between protein abundance and anthocyanin content suggested that a metabolic control point may exist for anthocyanin biosynthesis. This research provides insights into the process of anthocyanin formation in strawberry fruit at the level of protein concentration and reveals possible candidates in the regulation of anthocyanin formation during fruit ripening. To gain insight into the molecular mechanisms contributing to flavonoids and anthocyanin biosynthesis and regulation of strawberry fruit during ripening is challenging due to limited molecular biology tools and established hypothesis. Our targeted proteomic approach employing LC-MS/MS analysis and MRM technique to quantify proteins in relation to flavonoids and anthocyanin biosynthesis and regulation in strawberry fruit during fruit ripening is novel. The identification of peptides

  5. 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.

  6. DNA MUTAGENESIS IN PANAX GINSENG CELL CULTURES

    Directory of Open Access Journals (Sweden)

    Kiselev K.V.

    2012-08-01

    Full Text Available At the present time, it is well documented that plant tissue culture induces a number of mutations and chromosome rearrangements termed “somaclonal variations”. However, little is known about the nature and the molecular mechanisms of the tissue culture-induced mutagenesis and the effects of long-term subculturing on the rate and specific features of the mutagenesis. The aim of the present study was to investigate and compare DNA mutagenesis in different genes of Panax ginseng callus cultures of different age. It has previously been shown that the nucleotide sequences of the Agrobacterium rhizogenes rolC locus and the selective marker nptII developed mutations during long-term cultivation of transgenic cell cultures of P. ginseng. In the present work, we analyzed nucleotide sequences of selected plant gene families in a 2-year-old and 20-year-old P. ginseng 1c cell culture and in leaves of cultivated P. ginseng plants. We analysed sequence variability between the Actin genes, which are a family of house-keeping genes; the phenylalanine ammonia-lyase (PAL and dammarenediol synthase (DDS genes, which actively participate in the biosynthesis of ginsenosides; and the somatic embryogenesis receptor kinase (SERK genes, which control plant development. The frequency of point mutations in the Actin, PAL, DDS, and SERK genes in the 2-year-old callus culture was markedly higher than that in cultivated plants but lower than that in the 20-year-old callus culture of P. ginseng. Most of the mutations in the 2- and 20-year-old P. ginseng calli were A↔G and T↔C transitions. The number of nonsynonymous mutations was higher in the 2- and 20-year-old callus cultures than the number of nonsynonymous mutations in the cultivated plants of P. ginseng. Interestingly, the total number of N→G or N→C substitutions in the analyzed genes was 1.6 times higher than the total number of N→A or N→T substitutions. Using methylation-sensitive DNA fragmentation

  7. 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.

  8. 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