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Sample records for erwinia carotovora elicitors

  1. Erwinia carotovora elicitors and Botrytis cinerea activate defense responses in Physcomitrella patens

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    Bentancor Marcel

    2007-10-01

    Full Text Available Abstract Background Vascular plants respond to pathogens by activating a diverse array of defense mechanisms. Studies with these plants have provided a wealth of information on pathogen recognition, signal transduction and the activation of defense responses. However, very little is known about the infection and defense responses of the bryophyte, Physcomitrella patens, to well-studied phytopathogens. The purpose of this study was to determine: i whether two representative broad host range pathogens, Erwinia carotovora ssp. carotovora (E.c. carotovora and Botrytis cinerea (B. cinerea, could infect Physcomitrella, and ii whether B. cinerea, elicitors of a harpin (HrpN producing E.c. carotovora strain (SCC1 or a HrpN-negative strain (SCC3193, could cause disease symptoms and induce defense responses in Physcomitrella. Results B. cinerea and E.c. carotovora were found to readily infect Physcomitrella gametophytic tissues and cause disease symptoms. Treatments with B. cinerea spores or cell-free culture filtrates from E.c. carotovoraSCC1 (CF(SCC1, resulted in disease development with severe maceration of Physcomitrella tissues, while CF(SCC3193 produced only mild maceration. Although increased cell death was observed with either the CFs or B. cinerea, the occurrence of cytoplasmic shrinkage was only visible in Evans blue stained protonemal cells treated with CF(SCC1 or inoculated with B. cinerea. Most cells showing cytoplasmic shrinkage accumulated autofluorescent compounds and brown chloroplasts were evident in a high proportion of these cells. CF treatments and B. cinerea inoculation induced the expression of the defense-related genes: PR-1, PAL, CHS and LOX. Conclusion B. cinerea and E.c. carotovora elicitors induce a defense response in Physcomitrella, as evidenced by enhanced expression of conserved plant defense-related genes. Since cytoplasmic shrinkage is the most common morphological change observed in plant PCD, and that harpins and B

  2. Genetic control of resistance to soft rot caused by Erwinia carotovora subsp carotovora in Zantedeschia spp. (Araceae), section Aestivae

    NARCIS (Netherlands)

    Snijder, R.C.; Lindhout, W.H.; Tuyl, van J.M.

    2004-01-01

    The pattern of heredity of resistance to Erwinia carotovora subsp. carotovora in Zantedeschia spp. is investigated. Four species with different resistance levels (Z. albomaculata, Z. elliotiana, Z. pentlandii, Z. rehmannii) were compared to their reciprocal offspring. The occurrence of

  3. Novas ocorrências de Erwinia carotovora subsp. carotovora e de E. chrysanthemi

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    Irene M. G. Almeida

    1997-05-01

    Full Text Available Em continuidade a trabalhos de caracterização de bactérias pectinolíticas do gênero Eruia ocorrendo no Brasil, são relacionadas novas ocorrências dessas fitobactérias em plantios comerciais, que ocasionam podridão mole em cinco espécies de plantas ornamentais. Testes bioquímicas, fisiológicos, culturais e de patogenicidade permitiram comprovar a ocorrência de Erwinia carotovora subsp. carotovora em plantas de afelandra, amarílis e copo-de-leite, e de Erwiniachr santhemiemcordilineekalanchoe.

  4. Podridão em cravo causada por Erwinia carotovora subsp. carotovora no Brasil.

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    Irene M. G. Almeida

    2000-05-01

    Full Text Available De fevereiro a abril de 1999, coletaram-se estacas e mudas de cravo (Dianthus caryophyllus em propriedades dos municípios paulistas de Atibaia e Santo Antônio de Posse. Esse material apresentava sintomas caracterizados por não-emissão de raízes ou por podridão de raízes, colo e folhas basais, diferindo daqueles da doença denominada "slow wilt" e dos de escurecimento de vasos e necrose na região do colo, haste e folhas, já relatados em cravo. A partir de material com tais sintomas, isolaram-se bactérias, caracterizadas, mediante testes bioquímicos, culturais, fisiológicos e de patogenicidade, como Erwinia carotovora subsp. carotovora. Trata-se do primeiro relato desse patógeno em cravo no Brasil.

  5. PENGARUH SUMBER MINERAL TERHADAP PENEKANAN Erwinia carotovora OLEH PSEUDOMONAS PENDAR-FLUOR SECARA IN VITRO

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    Hardian Susilo Addy .

    2012-02-01

    Full Text Available Antimicrobial Stimulation of Fluorescent Pseudomonad to Inhibit Soft-rot Pathogen Caused by Erwinia carotovora subsp. Carotovora. This research was conducted to study effect of mineral sources on inhibition Erwinia carotovora by fluorescent pseudomonad. We used several mineral sources to stimulate antimicrobial substances from fluorescent pseudomonad that responsible to inhibit E. carotovora subsp. carotovora in vitro. The results showed that zinc 0,5 mM were the best to increase antagonistics of fluorescent psudomonad againts E. carotovora. Zinc were increased antimicrobial substances twohold compared with control without stimulant agent. Detection of antimicrobial substance using TLC showed that only one antimicrobial was detected with retention factor (Rf of 0,68 – 0,72. However, identification and characterization of that substance is still needed.

  6. Molecular cloning and characterization of an Erwinia carotovora subsp. carotovora pectin lyase gene that responds to DNA-damaging agents.

    OpenAIRE

    McEvoy, J L; Murata, H; Chatterjee, A K

    1990-01-01

    recA-mediated production of pectin lyase (PNL) and the bacteriocin carotovoricin occurs in Erwinia carotovora subsp. carotovora 71 when this organism is subjected to agents that damage or inhibit the synthesis of DNA. The structural gene pnlA was isolated from a strain 71 cosmid gene library following mobilization of the cosmids into a moderate PNL producer, strain 193. The cosmid complemented pnl::Tn5 but not ctv::Tn5 mutations. A constitutive level of PNL activity was detected in RecA+ and ...

  7. Insecticidal Bacillus thuringiensis Silences Erwinia carotovora Virulence by a New Form of Microbial Antagonism, Signal Interference

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    Dong, Yi-Hu; Zhang, Xi-Fen; Xu, Jin-Ling; Zhang, Lian-Hui

    2004-01-01

    It is commonly known that bacteria may produce antibiotics to interfere with the normal biological functions of their competitors in order to gain competitive advantages. Here we report that Bacillus thuringiensis suppressed the quorum-sensing-dependent virulence of plant pathogen Erwinia carotovora through a new form of microbial antagonism, signal interference. E. carotovora produces and responds to acyl-homoserine lactone (AHL) quorum-sensing signals to regulate antibiotic production and expression of virulence genes, whereas B. thuringiensis strains possess AHL-lactonase, which is a potent AHL-degrading enzyme. B. thuringiensis did not seem to interfere with the normal growth of E. carotovora; rather, it abolished the accumulation of AHL signal when they were cocultured. In planta, B. thuringiensis significantly decreased the incidence of E. carotovora infection and symptom development of potato soft rot caused by the pathogen. The biocontrol efficiency is correlated with the ability of bacterial strains to produce AHL-lactonase. While all the seven AHL-lactonase-producing B. thuringiensis strains provided significant protection against E. carotovora infection, Bacillus fusiformis and Escherichia coli strains that do not process AHL-degradation enzyme showed little effect in biocontrol. Mutation of aiiA, the gene encoding AHL-lactonase in B. thuringiensis, resulted in a substantial decrease in biocontrol efficacy. These results suggest that signal interference mechanisms existing in natural ecosystems could be explored as a new version of antagonism for prevention of bacterial infections. PMID:14766576

  8. Podridão bacteriana em ciclâmen causada por Erwinia carotovora subsp. carotovora no Brasil.

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    Valdemar Atílio Malavolta Júnior

    2000-05-01

    Full Text Available Plantas de ciclâmen (Cyclamen sp. coletadas em plantios comerciais conduzidos sob cobertura plástica, nos municípios paulistas de Vargem Grande Paulista e Arujá, apresentavam sintomas caracterizados por podridão mole do bulbo, murcha progressiva e irreversível da planta e podridão do pecíolo foliar, acarretando morte das plantas infectadas. Desses tecidos, isolaram-se bactérias distinguidas por meio de testes bioquímicas, culturais, fisiológicos e de patogenicidade, como Erwinia carotovora subsp. carotovora. Trata-se do primeiro relato desse patógeno em cultura de ciclâmen no Brasil. Isolados bacterianos encontram-se depositados na Coleção de Culturas do Instituto Biológico, Seção de Bacteriologia Fitopatológica (IBSBF, sob os números de acesso 1447 e 1448.

  9. Simplification of vacuole structure during plant cell death triggered by culture filtrates of Erwinia carotovora.

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    Hirakawa, Yumi; Nomura, Toshihisa; Hasezawa, Seiichiro; Higaki, Takumi

    2015-01-01

    Vacuoles are suggested to play crucial roles in plant defense-related cell death. During programmed cell death, previous live cell imaging studies have observed vacuoles to become simpler in structure and have implicated this simplification as a prelude to the vacuole's rupture and consequent lysis of the plasma membrane. Here, we examined dynamics of the vacuole in cell cycle-synchronized tobacco BY-2 (Nicotiana tabacum L. cv. Bright Yellow 2) cells during cell death induced by application of culture filtrates of Erwinia carotovora. The filtrate induced death in about 90% of the cells by 24 h. Prior to cell death, vacuole shape simplified and endoplasmic actin filaments disassembled; however, the vacuoles did not rupture until after plasma membrane integrity was lost. Instead of facilitating rupture, the simplification of vacuole structure might play a role in the retrieval of membrane components needed for defense-related cell death. © 2014 Institute of Botany, Chinese Academy of Sciences.

  10. Production of endo-pectate lyase by two stage cultivation of Erwinia carotovora

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    Fukuoka, Satoshi; Kobayashi, Yoshiaki

    1987-02-26

    The productivity of endo-pectate lyase from Erwinia carotovora GIR 1044 was found to be greatly improved by two stage cultivation: in the first stage the bacterium was grown with an inducing carbon source, e.g., pectin, and in the second stage it was cultivated with glycerol, xylose, or fructose with the addition of monosodium L-glutamate as nitrogen source. In the two stage cultivation using pectin or glycerol as the carbon source the enzyme activity reached 400 units/ml, almost 3 times as much as that of one stage cultivation in a 10 liter fermentor. Using two stage cultivation in the 200 liter fermentor improved enzyme productivity over that in the 10 liter fermentor, with 500 units/ml of activity. Compared with the cultivation in Erlenmeyer flasks, fermentor cultivation improved enzyme productivity. The optimum cultivating conditions were agitation of 480 rpm with aeration of 0.5 vvm at 28 /sup 0/C. (4 figs, 4 tabs, 14 refs)

  11. Purification, Characterization, and Effect of Thiol Compounds on Activity of the Erwinia carotovora L-Asparaginase

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    Suchita C. Warangkar

    2010-01-01

    Full Text Available L-asparaginase was extracted from Erwinia carotovora and purified by ammonium sulfate fractionation (60–70%, Sephadex G-100, CM cellulose, and DEAE sephadex chromatography. The apparent Mr of enzyme under nondenaturing and denaturing conditions was 150 kDa and 37±0.5 kDa, respectively. L-asparaginase activity was studied in presence of thiols, namely, L-cystine (Cys, L-methionine (Met, N-acetyl cysteine (NAC, and reduced glutathione (GSH. Kinetic parameters in presence of thiols (10–400 M showed an increase in Vmax values (2000, 2223, 2380, 2500, and control 1666.7 moles mg−1min−1 and a decrease in K values (0.086, 0.076, 0.062, 0.055 and control 0.098 mM indicating nonessential mode of activation. KA values displayed propensity to bind thiols. A decrease in Vmax/K ratio in concentration plots showed inverse relationship between free thiol groups (NAC and GSH and bound thiol group (Cys and Met. Enzyme activity was enhanced in presence of thiol protecting reagents like dithiothreitol (DTT, 2-mercaptoethanol (2-ME, and GSH, but inhibited by p-chloromercurybenzoate (PCMB and iodoacetamide (IA.

  12. Halogenated furanones from the red alga, Delisea pulchra, inhibit carbapenem antibiotic synthesis and exoenzyme virulence factor production in the phytopathogen Erwinia carotovora

    DEFF Research Database (Denmark)

    Manefield, M.; Welch, M.; Givskov, Michael Christian

    2001-01-01

    The plant pathogen Erwinia carotovora regulates expression of virulence factors and antibiotic production via an N-3- oxohexanoyl-L-homoserine lactone (3-oxo-C6-HSL) dependent quorum sensing mechanism. The marine alga Delisea pulchra produces halogenated furanones known to antagonise 3-oxo-C6-HSL...

  13. Utilization of a thermosensitive episome bearing transposon TN10 to isolate Hfr donor strains of Erwinia carotovora subsp. chrysanthemi.

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    Kotoujansky, A; Lemattre, M; Boistard, P

    1982-04-01

    A thermosensitive episome bearing the transposon Tn10, F(Ts)::Tn10 Lac+, has been successfully transferred from Escherichia coli to several wild strains of the enterobacteria Erwinia carotovora subsp. chrysanthemi, which are pathogenic on Saintpaulia ionantha. In one of these strains, all of the characters controlled by this episome (Lac+, Tetr, Tra+) were expressed, and its replication was stopped at 40 degrees C and above. At 30 degrees C, the episome was easily transferred between strains derived from E. carotovora subsp. chrysanthemi 3937j and to E coli. Hfr donor strains were obtained from a F' strain of 3937j by selecting clones which grew at 40 degrees C on plates containing tetracycline. One of these strains, Hfrq, was examined in more detail: the characters Lac+ and Tetr were stabilized and did not segregate higher than its parental F' strain. The mating was most efficient at 37 degrees C on a membrane. Hfrq transferred its chromosome to recipient strains at high frequency and in a polarized fashion, as evidenced by the gradient of transfer frequencies, the kinetics of marker entry (in interrupted mating experiments), and the analysis of linkage between different markers. The chromosome of Hfrq was most probably transferred in the following sequence: origin...met...xyl...arg...ile...leu...thr...cys...pan...ura...gal...trp...his. ..pur... Moreover, this genetic transfer system proved to be efficient in strain construction.

  14. PR genes of apple: identification and expression in response to elicitors and inoculation with Erwinia amylovora

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    Kim Jihyun F

    2006-10-01

    Full Text Available Abstract Background In the past decade, much work has been done to dissect the molecular basis of the defence signalling pathway in plants known as Systemic Acquired Resistance (SAR. Most of the work has been carried out in model species such as Arabidopsis, with little attention paid to woody plants. However within the range of species examined, components of the pathway seem to be highly conserved. In this study, we attempted to identify downstream components of the SAR pathway in apple to serve as markers for its activation. Results We identified three pathogenesis related (PR genes from apple, PR-2, PR-5 and PR-8, which are induced in response to inoculation with the apple pathogen, Erwinia amylovora, but they are not induced in young apple shoots by treatment with known elicitors of SAR in herbaceous plants. We also identified three PR-1-like genes from apple, PR-1a, PR-1b and PR-1c, based solely on sequence similarity to known PR-1 genes of model (intensively researched herbaceous plants. The PR-1-like genes were not induced in response to inoculation with E. amylovora or by treatment with elicitors; however, each showed a distinct pattern of expression. Conclusion Four PR genes from apple were partially characterized. PR-1a, PR-2, PR-5 and PR-8 from apple are not markers for SAR in young apple shoots. Two additional PR-1-like genes were identified through in-silico analysis of apple ESTs deposited in GenBank. PR-1a, PR-1b and PR-1c are not involved in defence response or SAR in young apple shoots; this conclusion differs from that reported previously for young apple seedlings.

  15. Control of postharvest soft rot caused by Erwinia carotovora of vegetables by a strain of Bacillus amyloliquefaciens and its potential modes of action.

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    Zhao, Yancun; Li, Pengxia; Huang, Kaihong; Wang, Yuning; Hu, Huali; Sun, Ya

    2013-03-01

    Erwinia carotovora subsp. carotovora (Ecc), the causal agent of bacterial soft rot, is one of the destructive pathogens of postharvest vegetables. In this study, a bacterial isolate (BGP20) from the vegetable farm soil showed strong antagonistic activity against Ecc in vitro, and its twofold cell-free culture filtrate showed excellent biocontrol effect in controlling the postharvest bacterial soft rot of potatoes at 25 °C. The anti-Ecc metabolites produced by the isolate BGP20 had a high resistance to high temperature, UV-light and protease K. Based on the colonial morphology, cellular morphology, sporulation, and partial nucleotide sequences of 16S rRNA and gyrB gene, the isolate BGP20 was identified as Bacillus amyloliquefaciens subsp. plantarum. Further in vivo assays showed that the BGP20 cell culture was more effective in controlling the postharvest bacterial soft rot of green peppers and Chinese cabbages than its twofold cell-free culture filtrate. In contrast, the biocontrol effect and safety of the BGP20 cell culture were very poor on potatoes. In the wounds of potatoes treated with both the antagonist BGP20 and the pathogen Ecc, the viable count of Ecc was 31,746 times that of BGP20 at 48 h of incubation at 25 °C. But in the wounds of green peppers, the viable count of BGP20 increased 182.3 times within 48 h, and that of Ecc increased only 51.3 %. In addition, the treatment with both BGP20 and Ecc induced higher activity of phenylalanine ammonia-lyase (PAL) than others in potatoes. But the same treatment did not induce an increase of PAL activity in green peppers. In conclusion, the present study demonstrated that the isolate BGP20 is a promising candidate in biological control of postharvest bacterial soft rot of vegetables, but its main mode of action is different among various vegetables.

  16. Genetic variation in Zantedeschia spp. (Araceae) for resisance to soft rot caused by Erwina carotovora subsp. carotovora

    NARCIS (Netherlands)

    Snijder, R.C.; Cho, H.; Hendriks, M.M.W.B.; Lindhout, W.H.; Tuyl, van J.M.

    2004-01-01

    Bacterial soft rot caused by Erwinia carotovora subsp. carotovora is a major disease in Zantedeschia spp., particularly in cultivars from the section Aestivae. The disease can partially be controlled by cultivation measures, so a combination with resistant cultivars could effectively protect the

  17. Resistance to Erwinia spp. in potato (Solanum tuberosum L.)

    NARCIS (Netherlands)

    Allefs, S.

    1995-01-01

    Blackleg is a disease of potato, Solanum tuberosum , which is caused by the bacteria Erwinia carotovora subsp. carotovora ( Ecc ), E.c. subsp. atroseptica ( Eca ) or

  18. The presence and survival of soft rot (Erwinia) in flower bulb production systems

    NARCIS (Netherlands)

    Doorn, van J.; Vreeburg, P.J.M.; Leeuwen, van P.J.; Dees, R.H.L.

    2011-01-01

    Soft rot is causing increasing damage in the flower bulb industry. Bulbous ornamentals such as Hyacinthus, Dahlia, Iris, Muscari, Freesia and Zantedeschia can be infected. Soft rot in flower bulbs is mainly caused by Dickeya spp. (Dickeya spp.) and Erwinia carotovora subsp. carotovora

  19. Soft rot erwiniae: from genes to genomes.

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    Toth, Ian K; Bell, Kenneth S; Holeva, Maria C; Birch, Paul R J

    2003-01-01

    SUMMARY The soft rot erwiniae, Erwinia carotovora ssp. atroseptica (Eca), E. carotovora ssp. carotovora (Ecc) and E. chrysanthemi (Ech) are major bacterial pathogens of potato and other crops world-wide. We currently understand much about how these bacteria attack plants and protect themselves against plant defences. However, the processes underlying the establishment of infection, differences in host range and their ability to survive when not causing disease, largely remain a mystery. This review will focus on our current knowledge of pathogenesis in these organisms and discuss how modern genomic approaches, including complete genome sequencing of Eca and Ech, may open the door to a new understanding of the potential subtlety and complexity of soft rot erwiniae and their interactions with plants. The soft rot erwiniae are members of the Enterobacteriaceae, along with other plant pathogens such as Erwinia amylovora and human pathogens such as Escherichia coli, Salmonella spp. and Yersinia spp. Although the genus name Erwinia is most often used to describe the group, an alternative genus name Pectobacterium was recently proposed for the soft rot species. Ech mainly affects crops and other plants in tropical and subtropical regions and has a wide host range that includes potato and the important model host African violet (Saintpaulia ionantha). Ecc affects crops and other plants in subtropical and temperate regions and has probably the widest host range, which also includes potato. Eca, on the other hand, has a host range limited almost exclusively to potato in temperate regions only. Disease symptoms: Soft rot erwiniae cause general tissue maceration, termed soft rot disease, through the production of plant cell wall degrading enzymes. Environmental factors such as temperature, low oxygen concentration and free water play an essential role in disease development. On potato, and possibly other plants, disease symptoms may differ, e.g. blackleg disease is associated

  20. Detection of soft rot Erwinia spp. on seed potatoes: conductimetry versus dilution plating, PCR and serological assays

    NARCIS (Netherlands)

    Fraaije, B.A.; Appels, M.; Boer, de S.H.; Vuurde, van J.W.L.; Bulk, van den R.W.

    1997-01-01

    Automated conductance measurements in polypectate medium were used for the detection of pathogenic soft rot Erwinia spp. in potato peel extracts. The detection threshold for Erwinia carotovora subsp. atroseptica (Eca) in inoculated peel extracts was ca. 104 colony forming units (cfu) ml-1 when

  1. Phenotypic and Genetic Characterization of Erwiniua carotovora spp. carotovora (JOnes Bergey et al. Isolates from Grafted Tomato in Sardinia, Italy

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    M. Fiori

    2005-04-01

    Full Text Available A disease symptomatically similar to that caused by Erwinia carotovora occurred on “Cuore di Bue” and “Cencara” tomato plants grafted on “Beaufort” and “He-Man”, or ungrafted, in greenhouses in Sardinia (Italy. Symptoms were: dark brown/black longitudinal stem lesions, soft stem rot, pith breakdown of the stems, hollow stems, vascular tissue discoloration, wilting and collapse of the plants. Numerous bacterial colonies from stem tissues were isolated on yeast extract salts (YS medium. Seven isolates (DPP As-1, DPP As-2, DPP As-3, DPP As-14, DPP Pu6, DPP Pu7 e DPP Pu8 were selected on the basis of their ability to cause rot on potato pieces and a hypersensitivity reaction in “White burley” tobacco leaves. Pathogenicity tests revealed that five of these isolates infected artichoke, basil, dwarf bean, fennel, marrow, melon, pepper, eggplant, grafted and ungrafted tomato, and white cabbage. Of the remaining two isolates, one (DPP As-1 did not infect white cabbage, and the other (DPP Pu8 did not infect basil, marrow or white cabbage. Phenotypic properties and ELISA, also performed on naturally infected tissues, revealed that all the isolates were E. c. ssp. carotovora (Jones Bergey et al. PCR-RFLP analysis placed two (DPP As-2 and DPP As-3 of the seven isolates in RFLP group 8. Five isolates belonged to a hitherto unknown RFLP group. Prevention and control measures for this disease are suggested.

  2. Caracterização de bactérias do género Erwinia causando podridões em plantas ornamentais no Brasil.

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    Irene M.G. Almeida

    1996-05-01

    Full Text Available São descritas as ocorrências de fito-bacterioses em plantios comerciais, ocasionando podridão mole em seis espécies de plantas ornamentais. Testes bioquímicos, fisiológicos, culturais e de patogenicidade permitiram cons-tatar a ocorrência de Erwinia carotovora subsp. carotovora em plantas de comigo-ninguém-pode e orquídea (Phalaenopsis, e de Erwinia chrysanthemi em amarilis, comigo-ninguém-pode, filodendro, orquídeas (Miltonia e Phalaenopsis e violeta africana.

  3. Erwinia chrysanthemi: pectolytic bacterium causing soft rot outbreaks of arracacha in Brazil Erwinia chrysanthemi: bactéria pectolítica envolvida na "mela" da mandioquinha-salsa no Brasil

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    Gilmar Paulo Henz

    2006-10-01

    Full Text Available The objetive of this work was to identify the pectolytic bacteria associated with soft rot of arracacha roots in Brazil. From 1998 to 2001, 227 isolates of Erwinia spp. were obtained from arracacha roots and identified by biochemical and physiological tests (pectolytic activity, lecithinase, a-methyl glucoside, phosphatase, erythromycin sensivity, growth at 37ºC. Of these isolates, 89.9% were identified as E. chrysanthemi (Ech, 9.7% as E. carotovora subsp. carotovora (Ecc and 0.5% as E. carotovora subsp. atroseptica. The identity of seventeen out of twenty representative isolates of Ech and Ecc was confirmed by PCR (primers '149f', 'L1r', 'ADE1', 'ADE2'.O objetivo deste trabalho foi identificar as bactérias pectolíticas envolvidas na podridão-mole de raízes de mandioquinha-salsa no Brasil. De 1998 a 2001, 227 isolados de Erwinia spp. foram obtidos de raízes de mandioquinha-salsa e identificados por testes bioquímicos e fisiológicos (atividade pectolítica, lecitinase, a-methyl glucosídeo, fosfatase, sensibilidade à eritromicina, crescimento a 37ºC. Destes isolados, 89,9% foram identificados como E. chrysanthemi (Ech, 9,7% como E. carotovora subsp. carotovora (Ecc e somente 0,5% como E. carotovora subsp. atroseptica. A identidade de 20 isolados representativos de Ech e Ecc foi confirmada por PCR (primers '149f', 'L1r', 'ADE1', 'ADE2', com exceção de dois isolados de Ech e um de Ecc.

  4. Synthetic Plant Defense Elicitors

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    Yasemin eBektas

    2015-01-01

    Full Text Available To defend themselves against invading pathogens plants utilize a complex regulatory network that coordinates extensive transcriptional and metabolic reprogramming. Although many of the key players of this immunity-associated network are known, the details of its topology and dynamics are still poorly understood. As an alternative to forward and reverse genetic studies, chemical genetics-related approaches based on bioactive small molecules have gained substantial popularity in the analysis of biological pathways and networks. Use of such molecular probes can allow researchers to access biological space that was previously inaccessible to genetic analyses due to gene redundancy or lethality of mutations. Synthetic elicitors are small drug like molecules that induce plant defense responses, but are distinct from known natural elicitors of plant immunity. While the discovery of the some synthetic elicitors had already been reported in the 1970s, recent breakthroughs in combinatorial chemical synthesis now allow for inexpensive high-throughput screens for bioactive plant defense-inducing compounds. Along with powerful reverse genetics tools and resources available for model plants and crop systems, comprehensive collections of new synthetic elicitors will likely allow plant scientists to study the intricacies of plant defense signaling pathways and networks in an unparalleled fashion. As synthetic elicitors can protect crops from diseases, without the need to be directly toxic for pathogenic organisms, they may also serve as promising alternatives to conventional biocidal pesticides, which often are harmful for the environment, farmers and consumers. Here we are discussing various types of synthetic elicitors that have been used for studies on the plant immune system, their modes-of-action as well as their application in crop protection.

  5. Predictive modelling of the combined effect of temperature and water activity on the in vitro growth of Erwinia spp. infecting potato tubers in Belgium

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    Moh, AA.

    2011-01-01

    Full Text Available Erwinia carotovora ssp. atroseptica (Eca, Erwinia carotovora ssp. carotovora (Ecc and Erwinia chrysanthemi (Ech, are the main cause of potato tuber decay (soft rot in storage and stem rot in the field (blackleg. The bacteria are characterized by the production of several extracellular pectic enzymes among them Pectate Lyase (PEL activity is the most important key of pathogenesis. It has been reported that ecological parameters such as humidity and temperature, greatly influence the disease development. The objective of this work was to determine the in vitro effect of water activity (0.960, 0.980, 0.997 and temperature (10, 15 and 20°C and their interactions on the growth parameters of Eca, Ecc and Ech using optical density (OD measurement. The maximum specific growth rate (µmax was calculated under each aw-temperature combinations for the three Erwinia species. Statistical analysis showed a significant effect of aw and temperature on µmax. We noticed that Eca and Ecc grow faster than Ech in our condition. A second aim of this work was to monitor the PEL specific activity under the combined effect of these two factors (aw-temperature. Our results showed an increase of PEL specific activity with the temperature whatever are the bacterial strains. But contrary to growth, this research did not show an increase of PEL specific activity with aw except the treatment at 15 and 20°C for all bacteria strains. According to our obtained results on growth and PEL production we concluded that Eca 03034/1 and Ecc 030033 had the same ecological behavior comparatively to Ech 03/016/1 in the range of the values of the two factors (aw and temperature investigated here. To our knowledge, this research is the first publication which pointed out the combined in vitro effect of aw and temperature on the growth of Erwinia genius according to literature data.

  6. Pectate lyase PelI of Erwinia chrysanthemi 3937 belongs to a new family.

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    Shevchik, V E; Robert-Baudouy, J; Hugouvieux-Cotte-Pattat, N

    1997-12-01

    Erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pel4, pelB, pelC, pelD, and pelE genes and a set of secondary pectate lyases, two of which, pelL and pelZ, have been already identified. We cloned the pelI gene, encoding a ninth pectate lyase of E. chrysanthemi 3937. The pelI reading frame is 1,035 bases long, corresponding to a protein of 344 amino acids including a typical amino-terminal signal sequence of 19 amino acids. The purified mature PelI protein has an isoelectric point of about 9 and an apparent molecular mass of 34 kDa. PelI has a preference for partially methyl esterified pectin and presents an endo-cleaving activity with an alkaline pH optimum and an absolute requirement for Ca2+ ions. PelI is an extracellular protein secreted by the Out secretory pathway of E. chrysanthemi. The PelI protein is very active in the maceration of plant tissues. A pelI mutant displayed reduced pathogenicity on chicory leaves, but its virulence did not appear to be affected on potato tubers or Saintpaulia ionantha plants. The pelI gene constitutes an independent transcriptional unit. As shown for the other pel genes, the transcription of pelI is dependent on various environmental conditions. It is induced by pectic catabolic products and affected by growth phase, oxygen limitation, temperature, nitrogen starvation, and catabolite repression. Regulation of pelI expression appeared to be dependent on the three repressors of pectinase synthesis, KdgR, PecS, and PecT, and on the global activator of sugar catabolism, cyclic AMP receptor protein. A functional KdgR binding site was identified close to the putative pelI promoter. Analysis of the amino acid sequence of PelI revealed high homology with a pectate lyase from Erwinia carotovora subsp. carotovora (65% identity) and low homology with pectate lyases of the phytopathogenic fungus Nectria haematococca (Fusarium solani). This finding indicates that PelI belongs to pectate lyase class

  7. 'Preventie belangrijkste troef tegen Erwinia'

    NARCIS (Netherlands)

    Doorn, van J.

    2012-01-01

    De bollenteelt en -handel ondervindt aanzienlijke schade van de bacterieziekte Erwinia. Onderzoek wijst uit dat preventie het belangrijkste wapen is. Mogelijk bieden ook stofjes die de afweer van planten verbeteren een oplossing.

  8. Fermentation of D-xylose and L-arabinose to ethanol by Erwinia chrysanthemi

    Energy Technology Data Exchange (ETDEWEB)

    Tolan, J.S.; Finn, R.K.

    1987-09-01

    Erwinia spp. are gram-negative facultative anaerobes within the family Enterobacteriacae which possess several desirable traits for the conversion of pentose sugars to ethanol, such as the ability to ferment a broad range of carbohydrates and the ease with which they can be genetically modified. Twenty-eight strains of Erwinia carotovora and E. chrysanthemi were screened for the ability to ferment D-xylose to ethanol. E. chrysanthemi B374 was chosen for further study on the basis of its superior (4%) ethanol tolerance. They have characterized the fermentation of D-xylose and L-arabinose by the wild type and mutants which bear plasmids containing the pyruvate decarboxylase gene from Zymomonas mobilis. Expression of the gene markedly increased the yields of ethanol (from 0.7 up to 1.45 mol/mol of xylose) and decreased the yields of formate, acetate, and lactate. However, the cells with pyruvate decarboxylase grew only one-fourth as fast as the wild type and tolerated only 2% ethanol. Alcohol tolerance was stimulated by the addition of yeast extract to the growth medium. Xylose catabolism was characterized by a high saturation constant K/sub s/ (4.5 mM).

  9. Polymyxin P is the active principle in suppressing phytopathogenic Erwinia spp. by the biocontrol rhizobacterium Paenibacillus polymyxa M-1.

    Science.gov (United States)

    Niu, Ben; Vater, Joachim; Rueckert, Christian; Blom, Jochen; Lehmann, Maik; Ru, Jin-Jiang; Chen, Xiao-Hua; Wang, Qi; Borriss, Rainer

    2013-06-18

    Nine gene clusters dedicated to nonribosomal synthesis of secondary metabolites with possible antimicrobial action, including polymyxin and fusaricidin, were detected within the whole genome sequence of the plant growth-promoting rhizobacterium (PGPR) Paenibacillus polymyxa M-1. To survey the antimicrobial compounds expressed by M-1 we analyzed the active principle suppressing phytopathogenic Erwinia spp. P. polymyxa M-1 suppressed the growth of phytopathogenic Erwinia amylovora Ea 273, and E. carotovora, the causative agents of fire blight and soft rot, respectively. By MALDI-TOF mass spectrometry and reversed-phase high-performance liquid chromatography (RP-HPLC), two antibacterial compounds bearing molecular masses of 1190.9 Da and 1176.9 Da were detected as being the two components of polymyxin P, polymyxin P1 and P2, respectively. The active principle acting against the two Erwinia strains was isolated from TLC plates and identified by postsource decay (PSD)-MALDI-TOF mass spectrometry as polymyxin P1 and polymyxin P2. These findings were corroborated by domain structure analysis of the polymyxin (pmx) gene cluster detected in the M-1 chromosome which revealed that corresponding to the chemical structure of polymyxin P, the gene cluster is encoding D-Phe in position 6 and L-Thr in position 7. Identical morphological changes in the cell wall of the bacterial phytopathogens treated with either crude polymyxin P or culture supernatant of M-1 corroborated that polymyxin P is the main component of the biocontrol effect exerted by strain M-1 against phytopathogenic Erwinia spp.

  10. Veredeling brengt inzicht in Erwinia-resistentie

    NARCIS (Netherlands)

    Snijder, R.; Paasen, van M.Q.P.; Tuyl, van J.M.

    2000-01-01

    Plant Research International, het voormalige CPRO-DLO, doet in opdracht van zes bedrijven onderzoek naar resistentiebronnen binnen Zantedeschia. Kort verslag van de resistentietoets voor Erwinia-rot en de eerste resultaten binnen het sortiment

  11. [Multiple change of phenotype, conjugated with the loss of yellow pigmentation of Erwinia herbicola].

    Science.gov (United States)

    Tovkach, F I; Tovkach, A F

    2004-01-01

    It has been shown that the loss of yellow pigmentation (phenotype Crt) of nonphotosynthesizing epiphyte bacterium Erwinia herbicola is accompanied by the loss of prototrophicity (phenotype Thi). Most Crt Thi-variants change the character of sensitivity to temperate erwiniophage E105 and bacteriocins (phenotype Ph/Bn). Some of them become sensitive to the killer effect of their own bacteriocins--autocins (phenotype Au). Multiple change of the phenotype in E. herbicola occurs so spontaneously as under variable growing of bacteria at the optimal and supraoptimal growth temperature. It is also established that the cells of one of the strains stop synthesizing the additional carotenoid or synthesize the changed products. It is shown that carotenoid synthesis in the cells of E. herbicola g157/5k may be reduced by means of transduction of the Crt phenotype by lipid-containing bacteriophage UA1. Multiple change of the phenotype connected with the loss of yellow pigmentation by E. herbicola was referred to the phenomenon of the population dissociation which is similar to that in E. carotovora.

  12. Toets op Erwinia in hyacint bijna praktijkklaar

    NARCIS (Netherlands)

    Dwarswaard, A.; PPO Bomen-bollen,

    2008-01-01

    Erwinia chrysanthemi houdt al enkele jaren de gemoederen in hyacint flink bezig. PPO en BKD werken in een van de onderzoeksprojecten naar deze bacterie samen aan de ontwikkeling van een toetsmethode voor de praktijk. PPO-onderzoeker Joop van Doorn en Hoofd laboratorium Ton van Schadewijk van de BKD

  13. Ziek en Zeer : Erwinia chrysanthemi in Amaryllidaceae

    NARCIS (Netherlands)

    Vink, P.

    2011-01-01

    In dit artikel een verslag van het onderzoek naar de gevoeligheid van narcissen voor de bacterie Erwinia chrysanthemi (tegenwoordig Dickeya dadantii). Uit een infectieproef is gebleken dat deze bacterie tijdens een reguliere bollenteelt in Lisse niet in staat was om narcisbollen aan te tasten. Toch

  14. Tropospheric ozone as a fungal elicitor

    Indian Academy of Sciences (India)

    Tropospheric ozone has been proven to trigger biochemical plant responses that are similar to the ones induced by an attack of fungal pathogens, i.e. it resembles fungal elicitors. This suggests that ozone can represent a valid tool for the study of stress responses and induction of resistance to pathogens. This review ...

  15. Comparative Genomics of Erwinia amylovora and Related Erwinia Species—What do We Learn?

    Directory of Open Access Journals (Sweden)

    Youfu Zhao

    2011-09-01

    Full Text Available Erwinia amylovora, the causal agent of fire blight disease of apples and pears, is one of the most important plant bacterial pathogens with worldwide economic significance. Recent reports on the complete or draft genome sequences of four species in the genus Erwinia, including E. amylovora, E. pyrifoliae, E. tasmaniensis, and E. billingiae, have provided us near complete genetic information about this pathogen and its closely-related species. This review describes in silico subtractive hybridization-based comparative genomic analyses of eight genomes currently available, and highlights what we have learned from these comparative analyses, as well as genetic and functional genomic studies. Sequence analyses reinforce the assumption that E. amylovora is a relatively homogeneous species and support the current classification scheme of E. amylovora and its related species. The potential evolutionary origin of these Erwinia species is also proposed. The current understanding of the pathogen, its virulence mechanism and host specificity from genome sequencing data is summarized. Future research directions are also suggested.

  16. Erwinia chrysanthemi in Amaryllidaceae : voortgezet diagnostisch onderzoek 2007

    NARCIS (Netherlands)

    Vink, P.

    2008-01-01

    De laatste jaren zien we bij veel bloembollen uit de familie van de Liliaceae, Iridaceae, Cannaceae en Compositae (hyacint, Muscari, Zantedeschia, Dahlia) problemen met een ernstige bacterieziekte die wordt veroorzaakt door Erwinia chrysanthemi. Metname bij hyacinten is deze ziekte problematisch

  17. Gezamenlijke toetsontwikkeling op Erwinia chrysanthemi in volle gang

    NARCIS (Netherlands)

    Doorn, van J.; Dees, R.H.L.; Martin, W.S.; Vreeburg, P.J.M.; Leeuwen, van P.J.

    2009-01-01

    Erwinia bezorgde menig ondernemer de afgelopen jaren de nodige hoofdbrekens. Onderzoek door PPO reikte al een aantal oplossingen aan. Nader onderzoek is gedaan naar de mogelijkheid om partijen te toetsen. In dit artkel de achtergronden bij dit onderzoek

  18. Erwinia in Zantedeschia : volgen van partijen en toetsen op tolerantie

    NARCIS (Netherlands)

    Leeuwen, van P.J.; Martin, W.S.; Dees, R.H.L.; Trompert, J.P.T.; Doorn, van J.

    2012-01-01

    De bloembollen- en de aardappelsector trekken gezamenlijk op binnen het koepel project Deltaplan Erwinia om het Erwiniaprobleem aan te pakken. Voor Zantedeschia is alleen de Erwiniabacteriesoort Pectobacterium carotovorum subsp. carotovorum (Pcc) een groot probleem. De afgelopen jaren is onderzocht

  19. ORGANOGENESIS OF CYMBIDIUM ORCHID USING ELICITORS

    Directory of Open Access Journals (Sweden)

    Jabun Nahar SYEDA

    2015-12-01

    Full Text Available Elicitors are substances that induce protective responses in plants. In this study, methyl jasmonate (Me-JA and lysozyme elicitation on PLBs culture of Cymbidium insigne in vitro was investigated. Elicitation by 0.1 mg/l Me-JA enhanced maximum PLB, shoot and root formation. The effects of lysozyme under white fluorescent tube, results indicated that every concentrations of lysozyme induced PLB, shoot and root formation and 0.1 mg/l lysozyme enhanced maximum formation of PLB, shoot and root compare with control. Lysozyme is known to play a vital role in medical industry and the present study firstly used lysozyme, as a plant growth regulator in Cymbidium tissue culture.

  20. Monitoring of Erwinia amylovora in Montenegro

    Directory of Open Access Journals (Sweden)

    Dragana Radunović

    2015-09-01

    Full Text Available Recent studies of Erwinia amylovora in Montenegro, conducted from 2012 to 2014, indicated that the bacterium was widespread in the northern, continental part of the country, where the most important fruit-growing regions are situated. The presence of the bacterium was confirmed on quince, pear, apple, medlar and hawthorn. Pathogenic, cultural and biochemical characteristics of E. amylovora strains sampled from pome fruit species and indigenous flora in Montenegro had been studied previously. In the present study, serological tests were used for identification of E. amylovora strains originating from pome fruit trees and indigenous plants. Monitoring of E. amylovora and collection of samples with symptoms of bacterial fire blight from different hosts and locations were performed in Montenegro from 2012 to 2014. Isolation of the bacterium on nutrient medium produced a large number of isolates, whose pathogenicity was confirmed on immature pear fruits. Twenty-seven strains of the bacterium, originating from three pome fruit species (quince, pear and apple and one indigenous species (hawthorn were selected for serological analyses. Two applied serological methods, ELISA and IF test, enabled rapid detection of the bacterium and simultaneous examination of a large number of samples over a short period of time. Serological analyses showed high homogeneity in antigenic structure of the studied E. amylovora strains sampled from quince, pear, apple and hawthorn from nine locations in Montenegro.

  1. Extracellular polysaccharide of Erwinia chrysanthemi A350 and ribotyping of Erwinia chrysanthemi spp.

    Science.gov (United States)

    Gray, J S; Yang, B Y; Montgomery, R

    2000-03-10

    Erwinia chrysanthemi spp. are gram-negative bacterial phytopathogens causing soft rots in a number of plants. The structure of the extracellular polysaccharide (EPS) produced by the E. chrysanthemi strain A350, which is a lacZ- mutant of the wild type strain 3937, pathogenic to Saintpaulia, has been determined using a combination of chemical and physical techniques including methylation analysis, low-pressure gel-filtration and anion-exchange chromatography, high-pH anion-exchange chromatography, partial acid hydrolysis, mass spectrometry and 1- and 2D NMR spectroscopy. In contrast to the structures of the EPS reported for other strains of E. chrysanthemi, the EPS from strain A350 contains D-GalA, together with L-Rhap and D-Galp in a 1:4:1 ratio. Evidence is presented for the following hexasaccharide repeat unit: [structure: see text] All the Erwinia chrysanthemi spp. studied to date have been analyzed by ribotyping and collated into families, which are consistent with the related structures of their EPS.

  2. Erwinia chrysanthemi ook bij ploffers in Dahlia boosdoener

    NARCIS (Netherlands)

    Leeuwen, van P.J.; Trompert, J.P.T.

    2006-01-01

    Sinds een aantal jaren komt bij de stekproduktie van Dahlia veel uitval voor door ploffers. Na het verhogen van de kastemperatuur vallen de knollen natrot weg. Bovendien kan verdere besmetting snel om zich heen grijpen. Onderzoek heeft aangetoond dat de bacterie Erwinia chrysanthemi de veroorzaker

  3. MAMPs/PAMPs - elicitors of innate immunity in plants

    DEFF Research Database (Denmark)

    Erbs, Gitte; Newman, Mari-Anne

    2009-01-01

    Patterns (MAMPs or PAMPs), are recognised by the plant innate immune systems Pattern Recognition Receptors (PRRs). General bacterial elicitors, like lipopolysaccharides (LPS), flagellin (Flg), elongation factor Tu (EF-Tu), cold shock protein (CSP), peptidoglycan (PGN) and the enzyme superoxide dismutase...... elicitors have, in recent years, been identified. Here, the current knowledge regarding bacterial elicitors of innate immunity in plants is presented...... (SodM) are known to act as MAMPs and induce immune responses in plants or plant cells (Gómez-Gómez and Boller, 2000; Erbs and Newman, 2003; Felix and Boller, 2003; Kunze et al., 2004; Watt et al., 2006, Gust et al., 2007; Erbs et al., unpublished). The corresponding PRRs for some of these bacterial...

  4. Growing bacteria shed elicitors of Drosophila humoral immunity.

    Science.gov (United States)

    Karlsson, Jenny; Oldenvi, Sandra; Fahlander, Carina; Daenthanasanmak, Anusara; Steiner, Håkan

    2012-01-01

    It has been much debated how the Drosophila immune system can recognize bacterial peptidoglycan that is often hidden. We show that bacteria separated from Drosophila S2 cells by a semipermeable membrane can upregulate the Imd pathway. Supernatants from exponentially growing but not from stationary-phase bacterial cultures induce antimicrobial peptides. It is also made likely that the shed elicitors are of peptidoglycan nature. Copyright © 2011 S. Karger AG, Basel.

  5. [Effects of fungal elicitor on inophyllums production in suspension cultured cells of Calophyllum inophyllum L].

    Science.gov (United States)

    Luo, Huan-liang; Guo, Yong; Cui, Tang-bing; Dai, Jian-guo; Zhang, Jun-song; Xu, Bai-qiu

    2004-04-01

    To investigate the effects of fungal elicitors on inophyllums production in suspension cultured cell of Calophyllum inophyllum Linn. The pathogen of leaf spot disease of C. inophyllum L. was isolated and prepared as fungal elicitor. The fungal elicitor was added to the medium with different concentrations and culture period. Their effects on biomass and inophyllums content of the suspension of cultured cells were studied. The optimum effects of S-I fungal elicitor concentrations on inophyllums content was 60 mg GE x L(-1). Adding the fungi elicitor into the cell suspension culture system at stationary phase (being cultured for 18 days) resulted in a highest inophyllum content of 59.174 mg x L(-1) at the 3rd day with 27% higher than control. Fungal elicitor treatment promoted the inophyllums accumulation in medium. Adding the Stagonospora curtisii (Berk.) Sacc. to the medium was effective approaches to enhance inophyllums yield in the suspension of C. inophyllum L culture cell.

  6. Biochemical Basis of Apple Leaf Resistance to Erwinia amylovora Infection

    Directory of Open Access Journals (Sweden)

    Marija Viljevac

    2009-01-01

    Full Text Available Erwinia amylovora is the most frequently found necrogenic bacterium on apple (Malus domestica Borkh. trees, which causes progressive necrosis and blight of host plants. Rapid spread of bacteria through the host tissue can lead to the loss of entire trees in one growing season. In this work, the aim is to investigate long-lasting biochemical responses in leaves of two apple cultivars (Enterprise and Golden delicious. Several histochemical (polyphenols, suberin and callose and biochemical parameters (total polyphenols, superoxide dismutase – SOD, ascorbate peroxidase – APX and guaiacol peroxidase – GPOD were screened 60 days after Erwinia inoculation in order to find their potential correlation with plant resistance mechanisms to the pathogen attack. Differential susceptibility to the pathogen attack observed between the investigated cultivars was in accordance with previous studies that characterized Enterprise as less susceptible and Golden delicious as more susceptible cultivar. Infected leaves of Golden delicious expressed symptoms seen as large brown areas at the abaxial side mostly placed at the leaf margin and necrosis also found peripherally, while damage in Enterprise leaves was observed as small brown spots and sporadic leaf edge necrosis. Increased SOD and GPOD activities combined with decreased polyphenol content as well as wide cuticle suberization in cultivar Enterprise should be considered as reliable biochemical parameters characterizing its ability to develop certain resistance to the pathogen infection. Furthermore, the absence of callose deposition in leaves of Enterprise confirmed our findings that thick suberized cuticle is likely the main defense mechanism that enables long-term efficient protection of apple leaves against biotic stress caused by Erwinia attack.

  7. Erwinia teleogrylli sp. nov., a Bacterial Isolate Associated with a Chinese Cricket.

    Directory of Open Access Journals (Sweden)

    Bo Liu

    Full Text Available A bacterial isolate (SCU-B244T was obtained in China from crickets (Teleogryllus occipitalis living in cropland deserted for approximately 10 years. The isolated bacteria were Gram-negative, facultatively anaerobic, oxidase-negative rods. A preliminary analysis of the 16S rRNA gene sequence indicated that the strain belongs to either the genus Erwinia or Pantoea. Analysis of multilocus sequence typing based on concatenated partial atpD, gyrB and infB gene sequences and physiological and biochemical characteristics indicated that the strain belonged to the genus Erwinia, as member of a new species as it was distinct from other known Erwinia species. Further analysis of the 16S rRNA gene showed SCU-B244T to have 94.71% identity to the closest species of that genus, Erwinia oleae (DSM 23398T, which is below the threshold of 97% used to discriminate bacterial species. DNA-DNA hybridization results (5.78±2.52% between SCU-B244T and Erwinia oleae (DSM 23398T confirmed that SCU-B244T and Erwinia oleae (DSM 23398T represent different species combined with average nucleotide identity values which range from 72.42% to 74.41. The DNA G+C content of SCU-B244T was 55.32 mol%, which also differs from that of Erwinia oleae (54.7 to 54.9 mol%. The polyphasic taxonomic approach used here confirmed that the strain belongs to the Erwinia group and represents a novel species. The name Erwinia teleogrylli sp. nov. is proposed for this novel taxon, for which the type strain is SCU-B244T (= CGMCC 1.12772T = DSM 28222T = KCTC 42022T.

  8. Use of elicitors as an approach for sustainable agriculture | Mejía ...

    African Journals Online (AJOL)

    On the other hand, plant-pathogen or microbe interactions generate multiple signals within plants activating defense mechanism, some of which can also be induced by elicitors (protective molecules). Elicitor-induced plant signaling serves as a guide to a series of intracellular events that end in activation of transduction ...

  9. Induced Resistance in Solanum lycopersicum by Algal Elicitor Extracted from Sargassum fusiforme

    Directory of Open Access Journals (Sweden)

    Layth Sbaihat

    2015-01-01

    Full Text Available Tomato (Solanum lycopersicum production relies heavily on the use of chemical pesticides, which is undesired by health- and environment-concerned consumers. Environment-friendly methods of controlling tomato diseases include agroecological practices, organic fungicides, and biological control. Plants’ resistance against pathogens is induced by applying agents called elicitors to the plants and would lead to disease prevention or reduced severity. We investigated the ability of a novel elicitor extracted from the brown sea algae (Sargassum fusiforme to elicit induced resistance in tomato. The studied elicitor induced hypersensitive cell death and O2- production in tomato tissues. It significantly reduced severities of late blight, grey mold, and powdery mildew of tomato. Taken together, our novel elicitor has not shown any direct antifungal activity against the studied pathogens, concluding that it is an elicitor of induced resistance.

  10. Siderophore‐mediated upregulation of Arabidopsis ferritin expression in response to Erwinia chrysanthemi infection

    National Research Council Canada - National Science Library

    Dellagi, Alia; Rigault, Martine; Segond, Diego; Roux, Camille; Kraepiel, Yvan; Cellier, Françoise; Briat, Jean‐François; Gaymard, Frédéric; Expert, Dominique

    2005-01-01

    ... ). To investigate whether iron sequestration in ferritins is a part of an iron‐withholding defense system induced in response to bacterial invasion, we used Arabidopsis thaliana as a susceptible host for the pathogenic bacterium Erwinia chrysanthemi...

  11. Isolation and Identification of L-asparaginase producing Erwinia strains which isolated from Potato Farms

    Directory of Open Access Journals (Sweden)

    Arastoo Badoei-Dalfard

    2016-09-01

    Full Text Available Introduction: L-Asparaginase can be effectively used for the treatment of lymphoblastic leukemia. The rapid growth of cancer cells are needed for L-asparagine abundant storage. L-asparaginase catalyzes the hydrolysis of L-asparagine into L-aspartic acid and ammonia. The purpose of this study was to isolate and identify the L-asparaginase producing Erwinia strains from the potato farms of Jiroft. Materials and methods: Pectolytic Erwinia species isolated from crumbling potato in M9 medium. The desired L-asparaginase producing bacteria were isolated based on the color changes. Biochemical-microbial and the plant pathogenicity tests of these strains were also investigated with potato and geranium. The L-asparaginase production and molecular detection of these Erwinia strains were also investigated. Results: In this study, L-asparaginase producing Erwinia was isolated on the CVP and M9 mediums. The inoculation of Erwinia strains on the potato and geranium plants showed that Er8 and Er11 species have the ability to cause plant pathogenicity. Results showed that the maximum pathogenicity of Er8 and Er11 was observed after 48 and 15 h of inoculation in potato and geranium plants, respectively. 16S rDNA sequencing and phylogenetic analyses exhibited that Er8 and Er11 strains were similar to Erwinia chrysanthemi with 98% homology. Discussion and conclusion: Because of several applications of the Erwinia L-asparaginase in various fields, isolated Erwinia and their L-asparaginase can be suitable for applied utilization.

  12. Structural Characterization of Core Region in Erwinia amylovora Lipopolysaccharide

    Directory of Open Access Journals (Sweden)

    Angela Casillo

    2017-03-01

    Full Text Available Erwinia amylovora (E. amylovora is the first bacterial plant pathogen described and demonstrated to cause fire blight, a devastating plant disease affecting a wide range of species including a wide variety of Rosaceae. In this study, we reported the lipopolysaccharide (LPS core structure from E. amylovora strain CFBP1430, the first one for an E. amylovora highly pathogenic strain. The chemical characterization was performed on the mutants waaL (lacking only the O-antigen LPS with a complete LPS-core, wabH and wabG (outer-LPS core mutants. The LPSs were isolated from dry cells and analyzed by means of chemical and spectroscopic methods. In particular, they were subjected to a mild acid hydrolysis and/or a hydrazinolysis and investigated in detail by one and two dimensional Nuclear Magnetic Resonance (NMR spectroscopy and ElectroSpray Ionization Fourier Transform-Ion Cyclotron Resonance (ESI FT-ICR mass spectrometry.

  13. Glycoconjugates as elicitors or suppressors of plant innate immunity

    DEFF Research Database (Denmark)

    Silipo, Alba; Erbs, Gitte; Shinya, Tomonori

    2010-01-01

    Innate immunity is the first line of defense against invading microorganisms in vertebrates and the only line of defense in invertebrates and plants. Bacterial glyco-conjugates, such as lipopolysaccharides (LPS) from the outer membrane of Gram-negative bacteria and peptidoglycan (PGN) from the cell...... walls of both Gram-positive and Gram-negative bacteria, and fungal and oomycete glycoconjugates such as oligosaccharides derived from the cell wall components ß-glucan, chitin and chitosan, have been found to act as elicitors of plant innate immunity. These conserved indispensable microbe......-specific molecules are also referred to as microbe-associated molecular patterns (MAMPs). Other glyco-conjugates such as bacterial extracellular polysaccharides (EPS) and cyclic glucan have been shown to suppress innate immune responses, thus conversely promoting pathogenesis. MAMPs are recognized by the plant...

  14. Impact of Exogenous Elicitors on Artemisinin Production and Trichome Density in

    National Research Council Canada - National Science Library

    Alka Jagdish DANGASH; Neeta PANDYA; Ashish BHARILLYA; Ashween JHALA; Dharamchand JAIN

    2014-01-01

    .... Therefore the factors affecting trichome initiation are important. In the present study, several strategies have been adapted to increase artemisinin production by treating them with nutrients, hormones and elicitors...

  15. CERK1, a LysM Receptor Kinase, Is Essential for Chitin Elicitor Signaling in Arabidopsis

    National Research Council Canada - National Science Library

    Ayako Miya; Premkumar Albert; Tomonori Shinya; Yoshitake Desaki; Kazuya Ichimura; Ken Shirasu; Yoshihiro Narusaka; Naoto Kawakami; Hanae Kaku; Naoto Shibuya

    2007-01-01

    ...(s) is required for signaling through the plasma membrane into the cytoplasm. Here, we identified a receptor-like kinase, designated CERK1, which is essential for chitin elicitor signaling in Arabidopsis...

  16. Identification of Erwinia species isolated from apples and pears by differential PCR.

    Science.gov (United States)

    Gehring, I; Geider, K

    2012-04-01

    Many pathogenic and epiphytic bacteria isolated from apples and pears belong to the genus Erwinia; these include the species E. amylovora, E. pyrifoliae, E. billingiae, E. persicina, E. rhapontici and E. tasmaniensis. Identification and classification of freshly isolated bacterial species often requires tedious taxonomic procedures. To facilitate routine identification of Erwinia species, we have developed a PCR method based on species-specific oligonucleotides (SSOs) from the sequences of the housekeeping genes recA and gpd. Using species-specific primers that we report here, differentiation was done with conventional PCR (cPCR) and quantitative PCR (qPCR) applying two consecutive primer annealing temperatures. The specificity of the primers depends on terminal Single Nucleotide Polymorphisms (SNPs) that are characteristic for the target species. These PCR assays enabled us to distinguish eight Erwinia species, as well as to identify new Erwinia isolates from plant surfaces. When performed with mixed bacterial cultures, they only detected a single target species. This method is a novel approach to classify strains within the genus Erwinia by PCR and it can be used to confirm other diagnostic data, especially when specific PCR detection methods are not already available. The method may be applied to classify species within other bacterial genera. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Dissecting the transcriptional response to elicitors in Vitis vinifera cells.

    Directory of Open Access Journals (Sweden)

    Lorena Almagro

    Full Text Available The high effectiveness of cyclic oligosaccharides like cyclodextrins in the production of trans-resveratrol in Vitis vinifera cell cultures is enhanced in the presence of methyl jasmonate. In order to dissect the basis of the interactions among the elicitation responses triggered by these two compounds, a transcriptional analysis of grapevine cell cultures treated with cyclodextrins and methyl jasmonate separately or in combination was carried out. The results showed that the activation of genes encoding enzymes from phenylpropanoid and stilbene biosynthesis induced by cyclodextrins alone was partially enhanced in the presence of methyl jasmonate, which correlated with their effects on trans-resveratrol production. In addition, protein translation and cell cycle regulation were more highly repressed in cells treated with cyclodextrins than in those treated with methyl jasmonate, and this response was enhanced in the combined treatment. Ethylene signalling was activated by all treatments, while jasmonate signalling and salicylic acid conjugation were activated only in the presence of methyl jasmonate and cyclodextrins, respectively. Moreover, the combined treatment resulted in a crosstalk between the signalling cascades activated by cyclodextrins and methyl jasmonate, which, in turn, provoked the activation of additional regulatory pathways involving the up-regulation of MYB15, NAC and WRKY transcription factors, protein kinases and calcium signal transducers. All these results suggest that both elicitors cause an activation of the secondary metabolism in detriment of basic cell processes like the primary metabolism or cell division. Crosstalk between cyclodextrins and methyl jasmonate-induced signalling provokes an intensification of these responses resulting in a greater trans-resveratrol production.

  18. Erwinia aphidicola, a new species isolated from pea aphid, Acyrthosiphon pisum.

    Science.gov (United States)

    Harada, Hosami; Oyaizu, Hiroshi; Kosako, Yoshimasa; Ishikawa, Hajime

    1997-12-01

    Five strains of Gram-negative, oxidase-negative, facultatively anaerobic, fermentative, motile, rod-shaped bacterium with the general characteristics of the family Enterobacteriaceae were isolated from the gut of multiple specimens of the pea aphid. All the strains caused aphid mortality when ingested by insects via a synthetic diet. The results of biochemical tests showed that these strains are most related to Erwinia herbicola and Pantoea agglomerans. According to DNA-DNA hybridization, the five strains showed more than 96% relatedness to each other, indicating that these organisms are members of a single species. These strains were most closely related to Erwinia herbicola (22% DNA relatedness). Phenotypic differentiation of these strains from Erwinia herbicola, which was also detected from aphid gut, was based on negative reactions in tests of yellow pigment production, gelatin liquefaction, acid production from inulin, starch and dulcitol, and positive acid production from melibiose, inositol, cellobiose and glycerol. On the basis of these data, the name Erwinia aphidicola is proposed for the new organism. The type strain is strain X 001 (=IAM 14479).

  19. A Stringent and Broad Screen of Solanum spp. tolerance Against Erwinia Bacteria Using a Petiole Test

    NARCIS (Netherlands)

    Rietman, H.; Finkers, H.J.; Evers, L.; Zouwen, van der P.S.; Wolf, van der J.M.; Visser, R.G.F.

    2014-01-01

    Blackleg and stem rot caused by coliform bacteria belonging to Dickeya spp. and Pectobacterium spp. (both referred to as Erwinia in this paper) are a problem for potato growers worldwide and no sources of high tolerance are currently present in the cultivated S. tuberosum gene pool. To find sources

  20. Characterization of the RcsC sensor kinase from Erwinia amylovora and other enterobacteria

    Science.gov (United States)

    RcsC is a hybrid sensor kinase which contains a sensor domain, a histidine kinase domain and a receiver domain. We have previously demonstrated that, while the Erwinia amylovora rcsC mutant produces more amylovoran than the wild type strain in vitro, the mutant remains avirulent on both immature pea...

  1. Effectieve kolonisatie van aardappelplanten door Dickeya-soorten (Erwinia chrysanthemi) : themanummer fytobacteriologie

    NARCIS (Netherlands)

    Wolf, van der J.M.; Czajkowski, R.L.; Velvis, H.

    2009-01-01

    De bacterieziekten zwartbenigheid en stengelnatrot, veroorzaakt door Pectobacterium en Dickeya (Erwinia)- soorten, berokkenen grote schade aan de pootaardappelteelt. Bij PRI en HZPC wordt onderzoek verricht naar de verspreiding van deze pathogenen tijdens teelt- en (na)oogst. Het was al bekend dat

  2. High-throughput screening of Erwinia chrysanthemi pectin methylesterase variants using carbohydrate microarrays

    DEFF Research Database (Denmark)

    Øbro, Jens; Sørensen, Iben; Derkx, Patrick

    2009-01-01

    the activity of a series of variant enzymes based on the PME from the important pathogen Erwinia chrysanthemi. A library of 99 E. chrysanthemi PME mutants was created in which seven amino acids were altered by various different substitutions. Each mutant PME was incubated with a highly methyl esterified lime...

  3. Cutaneous infection and bactaeremia caused by Erwinia billingiae: a case report

    Directory of Open Access Journals (Sweden)

    M. Prod'homme

    2017-09-01

    Full Text Available Cellulitis and erysipelas are common skin infections usually caused by Staphylococcus aureus and streptococci. Gram-negative rods are rarely implicated. We report here a case of dermohypodermitis and bactaeremia caused by Erwinia billingiae, a Gram-negative bacteria usually pathogenic and epiphytic to pome fruit tree.

  4. Cutaneous infection and bactaeremia caused byErwinia billingiae: a case report.

    Science.gov (United States)

    Prod'homme, M; Micol, L A; Weitsch, S; Gassend, J-L; Martinet, O; Bellini, C

    2017-09-01

    Cellulitis and erysipelas are common skin infections usually caused by Staphylococcus aureus and streptococci. Gram-negative rods are rarely implicated. We report here a case of dermohypodermitis and bactaeremia caused by Erwinia billingiae , a Gram-negative bacteria usually pathogenic and epiphytic to pome fruit tree.

  5. Cutaneous infection and bactaeremia caused by Erwinia billingiae: a case report

    OpenAIRE

    Prod'homme, M.; Micol, L.A.; Weitsch, S.; Gassend, J.-L.; Martinet, O.; Bellini, C.

    2017-01-01

    Cellulitis and erysipelas are common skin infections usually caused by Staphylococcus aureus and streptococci. Gram-negative rods are rarely implicated. We report here a case of dermohypodermitis and bactaeremia caused by Erwinia billingiae, a Gram-negative bacteria usually pathogenic and epiphytic to pome fruit tree.

  6. Bacterial leaf rot of Aloe vera L., caused byErwinia chrysanthemi biovar 3

    NARCIS (Netherlands)

    Laat, de P.C.A.; Verhoeven, J.T.W.; Danse, J.D.

    1994-01-01

    A severe attack of the bacteriumErwinia chrysantemi biovar 3 on the succulentAloe vera on the Carribean island of Aruba is described. Biochemical and pathological characteristics of strains are presented, including results of successful inoculation experiments onAloe vera. This is the first report

  7. Beheersing van Erwinia in bolgewassen : agressief snot en witsnot in hyacint, Zantedeschia, Dahlia en andere bloembolgewassen

    NARCIS (Netherlands)

    Doorn, van J.; Vreeburg, P.J.M.; Leeuwen, van P.J.

    2008-01-01

    De afgelopen acht jaar is in toenemende mate bacterierot (zachtrot, agressief rot) opgetreden in bloembolgewassen zoals hyacint, Muscari, Dahlia en iris. Ook in Freesia en Amaryllis zijn problemen; vooral de pootaardappelsector heeft grote schade door met name Erwinia chrysanthemi (agressief snot).

  8. Genetic islands in pome fruit pathogenic and nonpathogenic Erwinia species and related plasmids

    Directory of Open Access Journals (Sweden)

    Pablo eLlop

    2015-08-01

    Full Text Available New pathogenic bacteria species belonging to the genus Erwinia associated with pome fruit trees (Erwinia pyrifoliae, E. piriflorinigrans, E. uzenensis have been increasingly described in the last years, and comparative analyses have found that all these species share several genetic characteristics. Studies at different level (whole genome comparison, virulence genes, plasmid content, etc. show a high intraspecies homogeneity (i.e. among E. amylovora strains and also abundant similarities appear between the different Erwinia species: presence of plasmids of similar size in the pathogenic species; high similarity in several genes associated with exopolysaccharide production and hence, with virulence, as well as in some other genes, in the chromosomes. Many genetic similarities have been observed also among some of the plasmids (and genomes from the pathogenic species and E. tasmaniensis or E. billingiae, two epiphytic species on the same hosts. The amount of genetic material shared in this genus varies from individual genes to clusters, genomic islands and genetic material that even may constitute a whole plasmid. Recent research on evolution of erwinias point out the horizontal transfer acquisition of some genomic islands that were subsequently lost in some species and several pathogenic traits that are still present. How this common material has been obtained and is efficiently maintained in different species belonging to the same genus sharing a common ecological niche provides an idea of the origin and evolution of the pathogenic Erwinia and the interaction with nonpathogenic species present in the same niche, and the role of the genes that are conserved in all of them.

  9. Environmental stress and elicitors enhance taxol production by endophytic strains of Paraconiothyrium variabile and Epicoccum nigrum.

    Science.gov (United States)

    Somjaipeng, Supunnika; Medina, Angel; Magan, Naresh

    2016-08-01

    This study examined the effect of different elicitors (seven, different concentrations) and environmental factors (water activity (aw), pH) on taxol production by strains of two endophytic fungi, Paraconiothyrium variabile and Epicoccum nigrum, isolated from temperate yew trees. A defined liquid broth medium was modified with elicitors, solute aw depressors at different pH values. For P. variabile, the best elicitor was salicylic acid at 50mg/l which gave a taxol yield of 14.7±4.8μg/l. The study of synergistic effects between elicitor, aw and pH on taxol production showed that the highest yield of taxol (68.9±11.9μg/l) was produced under modified ionic stress of 0.98aw (KCl) at pH 5 when supplemented with 20mg/l of salicylic acid. For E. nigrum, serine was the best elicitor which increased yield significantly (29.6 fold) when KCL was used as the aw depressor (0.98aw) at pH 5.0 with 30mg/l of serine. The maximum taxol yield produced by E. nigrum was 57.1±11.8μg/l. Surface response models were used to build contour maps to determine the conditions for maximum and marginal conditions for taxol yield in relation to the best elicitor and aw, and the best pH for the first time. This will be beneficial for identifying key parameters for improvement of taxol yields by endophytic fungi. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Activation of shikimate, phenylpropanoid, oxylipins and auxin pathways in Pectobacterium carotovorum elicitors-treated moss

    Directory of Open Access Journals (Sweden)

    Alfonso eAlvarez

    2016-03-01

    Full Text Available Plants have developed complex defense mechanisms to cope with microbial pathogens. Pathogen-associated molecular patterns (PAMPs and damage-associated molecular patterns (DAMPs are perceived by pattern recognition receptors (PRRs, leading to the activation of defense. While substantial progress has been made in understanding the activation of plant defense by PAMPs and DAMPs recognition in tracheophytes, far less information exists on related processes in early divergent plants like mosses. The aim of this study was to identify genes that were induced in P. patens in response to elicitors of Pectobacterium carotovorum subsp. carotovorum, using a cDNA suppression subtractive hybridization (SSH method. A total of 239 unigenes were identified, including genes involved in defense responses related to the shikimate, phenylpropanoid and oxylipin pathways. The expression levels of selected genes related to these pathways were analyzed using quantitative RT-PCR, confirming their rapid induction by P.c. carotovorum derived elicitors. In addition, P. patens induced cell wall reinforcement after elicitor treatment by incorporation of phenolic compounds, callose deposition, and elevated expression of Dirigent-like encoding genes. Small molecule defense markers and phytohormones such as cinnamic acid, 12-oxo-phytodienoic acid and auxin levels all increased in elicitor-treated moss tissues. In contrast, salicylic acid levels decreased while abscisic acid levels remained unchanged. P. patens reporter lines harboring an auxin-inducible promoter fused to β-glucuronidase revealed GUS activity in protonemal and gametophores tissues treated with elicitors of P.c. carotovorum, consistent with a localized activation of auxin signaling. These results indicate that P. patens activates the shikimate, phenylpropanoid, oxylipins and auxin pathways upon treatment with P.c. carotovorum derived elicitors.

  11. Helicoverpa zea gut-associated bacteria indirectly induce defenses in tomato by triggering a salivary elicitor(s).

    Science.gov (United States)

    Wang, Jie; Peiffer, Michelle; Hoover, Kelli; Rosa, Cristina; Zeng, Rensen; Felton, Gary W

    2017-05-01

    Insect gut-associated microbes modulating plant defenses have been observed in beetles and piercing-sucking insects, but the role of caterpillar-associated bacteria in regulating plant induced defenses has not been adequately examined. We identified bacteria from the regurgitant of field-collected Helicoverpa zea larvae using 16S ribosomal RNA (rRNA) gene sequencing and matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. A combination of biochemical, molecular, and confocal electron microscopy methods were used to determine the role of caterpillar-associated bacteria in mediating defenses in Solanum lycopersicum (tomato). Laboratory-reared H. zea inoculated with one of the bacteria identified in field-collected H. zea, Enterobacter ludwigii, induced expression of the tomato defense-related enzyme polyphenol oxidase and genes regulated by jasmonic acid (JA), whereas the salicylic acid (SA)-responsive pathogenesis-related gene was suppressed. Additionally, saliva and its main component glucose oxidase from inoculated caterpillars played an important role in elevating tomato anti-herbivore defenses. However, there were only low detectable amounts of regurgitant or bacteria on H. zea-damaged tomato leaves. Our results suggest that H. zea gut-associated bacteria indirectly mediate plant-insect interactions by triggering salivary elicitors. These findings provide a proof of concept that introducing gut bacteria to a herbivore may provide a novel approach to pest management through indirect induction of plant resistance. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  12. Genome comparison of the epiphytic bacteria Erwinia billingiae and E. tasmaniensis with the pear pathogen E. pyrifoliae

    National Research Council Canada - National Science Library

    Kube, Michael; Migdoll, Alexander M; Gehring, Isabel; Heitmann, Katja; Mayer, Yvonne; Kuhl, Heiner; Knaust, Florian; Geider, Klaus; Reinhardt, Richard

    2010-01-01

    .... Important pathogens such as Erwinia amylovora, the causative agent of fire blight and E. pyrifoliae causing bacterial shoot blight of pear in Asia belong to this genus. The species E. tasmaniensis and E...

  13. Effect of elicitors on the production of gossypol and methylated gossypol in cotton hairy roots

    Science.gov (United States)

    The effect of two-chemical elicitors, salicylic acid and methyl jasmonate, on the production of gossypol, 6-methoxy gossypol, and 6,6'-dimethoxy gossypol in Gossypium barbadense hairy roots was examined. Methyl jasmonate, but not salicylic acid, was found to increase the production of gossypol and ...

  14. A paralog of the proteinaceous elicitor sm1 affects colonization of maize roots by Trichoderma virens

    Science.gov (United States)

    The biocontrol agent, Trichoderma virens, has the ability to protect plants from pathogens by eliciting plant defense responses, involvement in mycoparasitism, or secreting antagonistic secondary metabolites. SM1, an elicitor of induced systemic resistance (ISR), was found to have three paralogs wi...

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

    Science.gov (United States)

    Kar, Itishree; Mukherjee, Arup K.; Acharya, Priyambada

    2013-01-01

    We investigated on important parameters of induced resistance in hydroponic tomato (Solanum lycopersicum) against Ralstonia solanacearum using the elicitors chitosan (CHT), salicylic acid (SA), and jasmonic acid (JA). The increase in total phenolic content of roots by the elicitors was significantly higher than control. Most pronounced increase in lignin synthesis was triggered by SA followed by CHT. At 24 h post-elicitation (hpe), the activity of phenylalanine ammonia lyase was 4.5 times higher than control elicited by CHT. The peroxidase activity was about 86 nkat/mg protein at 24 hpe in case of SA and 78 nkat/mg protein in case of CHT. The activity of polyphenol oxidase increased several folds by the elicitors. Cinnamyl alcohol dehydrogenase activity increased to the maximum at 48 hpe under the influence of CHT. The results indicate that the elicitors SA and CHT induced effective defense responses in tomato plants against R. solanacearum. This was evident from reduced vascular browning and wilting symptoms of tomato plants treated with SA and CHT and challenged subsequently with R. solanacearum. This reduced disease incidence in tomato by SA and CHT may be a result of cell wall strengthening through deposition of lignin and the coincident induction of defense enzymes. PMID:24187521

  16. Erwinia mallotivora sp., a new pathogen of papaya (Carica papaya) in Peninsular Malaysia.

    Science.gov (United States)

    Amin, Noriha Mat; Bunawan, Hamidun; Redzuan, Rohaiza Ahmad; Jaganath, Indu Bala S

    2010-12-24

    Erwinia mallotivora was isolated from papaya infected with dieback disease showing the typical symptoms of greasy, water-soaked lesions and spots on leaves. Phylogenetic analysis of 16S rRNA gene sequences showed that the strain belonged to the genus Erwinia and was united in a monophyletic group with E. mallotivora DSM 4565 (AJ233414). Earlier studies had indicated that the causal agent for this disease was E. papayae. However, our current studies, through Koch's postulate, have confirmed that papaya dieback disease is caused by E. mallotivora. To our knowledge, this is the first new discovery of E. mallotivora as a causal agent of papaya dieback disease in Peninsular Malaysia. Previous reports have suggested that E. mallotivora causes leaf spot in Mallotus japonicus. However, this research confirms it also to be pathogenic to Carica papaya.

  17. Erwinia mallotivora sp., a New Pathogen of Papaya (Carica papaya in Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Noriha Mat Amin

    2010-12-01

    Full Text Available Erwinia mallotivora was isolated from papaya infected with dieback disease showing the typical symptoms of greasy, water-soaked lesions and spots on leaves. Phylogenetic analysis of 16S rRNA gene sequences showed that the strain belonged to the genus Erwinia and was united in a monophyletic group with E. mallotivora DSM 4565 (AJ233414. Earlier studies had indicated that the causal agent for this disease was E. papayae. However, our current studies, through Koch’s postulate, have confirmed that papaya dieback disease is caused by E. mallotivora. To our knowledge, this is the first new discovery of E. mallotivora as a causal agent of papaya dieback disease in Peninsular Malaysia. Previous reports have suggested that E. mallotivora causes leaf spot in Mallotus japonicus. However, this research confirms it also to be pathogenic to Carica papaya.

  18. The Phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) Is a Pathogen of the Pea Aphid†

    OpenAIRE

    Grenier, Anne-Marie; Duport, Gabrielle; Pagès, Sylvie; Condemine, Guy; Rahbé, Yvan

    2006-01-01

    Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, eit...

  19. Draft Genome Sequence of Erwinia tracheiphila, an Economically Important Bacterial Pathogen of Cucurbits.

    Science.gov (United States)

    Shapiro, Lori R; Scully, Erin D; Roberts, Dana; Straub, Timothy J; Geib, Scott M; Park, Jihye; Stephenson, Andrew G; Salaau Rojas, Erika; Liu, Quin; Beattie, Gwyn; Gleason, Mark; De Moraes, Consuelo M; Mescher, Mark C; Fleischer, Shelby G; Kolter, Roberto; Pierce, Naomi; Zhaxybayeva, Olga

    2015-06-04

    Erwinia tracheiphila is one of the most economically important pathogens of cucumbers, melons, squashes, pumpkins, and gourds in the northeastern and midwestern United States, yet its molecular pathology remains uninvestigated. Here, we report the first draft genome sequence of an E. tracheiphila strain isolated from an infected wild gourd (Cucurbita pepo subsp. texana) plant. The genome assembly consists of 7 contigs and includes a putative plasmid and at least 20 phage and prophage elements. Copyright © 2015 Shapiro et al.

  20. Regulation and role in pathogenicity of Erwinia chrysanthemi 3937 pectin methylesterase.

    Science.gov (United States)

    Boccara, M; Chatain, V

    1989-07-01

    The gene pem, encoding the pectin methylesterase (PME) of Erwinia chrysanthemi 3937, was cloned and mutagenized by mini-Mu transposable elements. A second gene, pecY, which could act as a negative regulator of PME was found 5' to the pem gene. A PME-E. chrysanthemi derivative inoculate onto Saintpaulia plants was shown to be clearly noninvasive, demonstrating the important role of this enzyme in soft rot disease.

  1. Bacteriocin-resistant mutants of Erwinia chrysanthemi: possible involvement of iron acquisition in phytopathogenicity.

    Science.gov (United States)

    Expert, D; Toussaint, A

    1985-07-01

    A series of bacteriocin-resistant mutants of Erwinia chrysanthemi 3937JRH were unable to elicit soft-rot symptoms on saintpaulia plants. The loss of pathogenicity was correlated with the disappearance of one to three outer membrane polypeptides (molecular weights, about 80,000 to 90,000) whose production in wild-type strains was greatly enhanced under iron-limited growth conditions. The mutants did not exhibit altered extracellular pectinolytic or cellulolytic activities.

  2. NCBI nr-aa BLAST: CBRC-XTRO-01-0063 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-0063 ref|YP_049915.1| probable transporter [Erwinia carotovora subsp. atroseptic...a SCRI1043] emb|CAG74721.1| probable transporter [Erwinia carotovora subsp. atroseptica SCRI1043] YP_049915.1 8e-37 38% ...

  3. NCBI nr-aa BLAST: CBRC-CREM-01-1309 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CREM-01-1309 ref|YP_048869.1| hypothetical protein ECA0757 [Erwinia carotovora subsp. atroseptic...a SCRI1043] emb|CAG73671.1| putative membrane protein [Erwinia carotovora subsp. atroseptica SCRI1043] YP_048869.1 1e-49 46% ...

  4. NCBI nr-aa BLAST: CBRC-CREM-01-1338 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CREM-01-1338 ref|YP_049675.1| probable transporter [Erwinia carotovora subsp. atroseptic...a SCRI1043] emb|CAG74479.1| probable transporter [Erwinia carotovora subsp. atroseptica SCRI1043] YP_049675.1 2e-71 52% ...

  5. NCBI nr-aa BLAST: CBRC-PMAR-01-0259 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PMAR-01-0259 ref|YP_050115.1| putative sulfate transporter [Erwinia carotovora subsp. atroseptic...a SCRI1043] emb|CAG74922.1| putative sulfate transporter [Erwinia carotovora subsp. atroseptica SCRI1043] YP_050115.1 5.1 48% ...

  6. NCBI nr-aa BLAST: CBRC-XTRO-01-0638 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-0638 ref|YP_052263.1| hypothetical protein ECA4176 [Erwinia carotovora subsp. atroseptic...a SCRI1043] emb|CAG77073.1| putative membrane protein [Erwinia carotovora subsp. atroseptica SCRI1043] YP_052263.1 5e-46 44% ...

  7. NCBI nr-aa BLAST: CBRC-AGAM-07-0002 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-AGAM-07-0002 ref|YP_050752.1| hypothetical protein ECA2661 [Erwinia carotovora subsp. atroseptic...a SCRI1043] emb|CAG75561.1| putative membrane protein [Erwinia carotovora subsp. atroseptica SCRI1043] YP_050752.1 2e-66 53% ...

  8. NCBI nr-aa BLAST: CBRC-PTRO-10-0063 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PTRO-10-0063 ref|YP_048760.1| galacturonate transporter [Erwinia carotovora subsp. atroseptic...a SCRI1043] emb|CAG73559.1| galacturonate transporter [Erwinia carotovora subsp. atroseptica SCRI1043] YP_048760.1 0.94 28% ...

  9. NCBI nr-aa BLAST: CBRC-XTRO-01-2352 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-2352 ref|YP_052273.1| hypothetical protein ECA4186 [Erwinia carotovora subsp. atroseptic...a SCRI1043] emb|CAG77083.1| putative membrane protein [Erwinia carotovora subsp. atroseptica SCRI1043] YP_052273.1 2.5 32% ...

  10. NCBI nr-aa BLAST: CBRC-PTRO-09-0001 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PTRO-09-0001 ref|YP_048760.1| galacturonate transporter [Erwinia carotovora subsp. atroseptic...a SCRI1043] emb|CAG73559.1| galacturonate transporter [Erwinia carotovora subsp. atroseptica SCRI1043] YP_048760.1 0.050 33% ...

  11. Dynamic regulation of GacA in type III secretion, pectinase gene expression, pellicle formation, and pathogenicity of Dickeya dadantii (Erwinia chrysanthemi 3937).

    Science.gov (United States)

    Yang, Shihui; Peng, Quan; Zhang, Qiu; Yi, Xuan; Choi, Chang Jae; Reedy, Ralph M; Charkowski, Amy O; Yang, Ching-Hong

    2008-01-01

    Dickeya dadantii (Erwinia chrysanthemi 3937) secretes exoenzymes, including pectin-degrading enzymes, leading to the loss of structural integrity of plant cell walls. A type III secretion system (T3SS) is essential for full virulence of this bacterium within plant hosts. The GacS/GacA two-component signal transduction system participates in important biological roles in several gram-negative bacteria. In this study, a gacA deletion mutant (Ech137) of D. dadantii was constructed to investigate the effect of this mutation on pathogenesis and other phenotypes. Compared with wild-type D. dadantii, Ech137 had a delayed biofilm-pellicle formation. The production of pectate lyase (Pel), protease, and cellulase was diminished in Ech137 compared with the wild-type cells. Reduced transcription of two endo-Pel genes, pelD and pelL, was found in Ech137 using a green fluorescence protein-based fluorescence-activated cell sorter promoter activity assay. In addition, the transcription of T3SS genes dspE (an effector), hrpA (a structural protein of the T3SS pilus), and hrpN (a T3SS harpin) was reduced in Ech137. A lower amount of rsmB regulatory RNA was found in gacA mutant Ech137 compared with the wild-type bacterium by quantitative reverse-transcription polymerase chain reaction. Compared with wild-type D. dadantii, a lower amount of hrpL mRNA was observed in Ech137 at 12 h grown in medium. Although the role of RsmA, rsmB, and RsmC in D. dadantii is not clear, from the regulatory pathway revealed in E. carotovora, the lower expression of dspE, hrpA, and hrpN in Ech137 may be due to a post-transcriptional regulation of hrpL through the Gac-Rsm regulatory pathway. Consequently, the reduced exoenzyme production and Pel gene expression in the mutant may be sue partially to the regulatory role of rsmB-RsmA on exoenzyme expression. Similar to in vitro results, a lower expression of T3SS and pectinase genes of Ech137 also was observed in bacterial cells inoculated into Saintpaulia

  12. Impact of Exogenous Elicitors on Artemisinin Production and Trichome Density in Artemisia annua L. under Subtropical Conditions

    National Research Council Canada - National Science Library

    Alka Jagdish DANGASH; Neeta PANDYA; Ashish BHARILLYA; Ashween JHALA; Dharamchand JAIN

    2014-01-01

    .... Therefore the factors affecting trichome initiation are important. In the present study, several strategies have been adapted to increase artemisinin production by treating them with nutrients, hormones and elicitors...

  13. Effects of Combined Elicitors on Tanshinone Metabolic Profiling and SmCPS Expression in Salvia miltiorrhiza Hairy Root Cultures

    Directory of Open Access Journals (Sweden)

    Yujia Liu

    2013-06-01

    Full Text Available Tanshinones are abietane-type norditerpenoid quinone natural products found in a well-known traditional Chinese medicinal herb, Salvia miltiorrhiza Bunge. The copalyl diphosphate synthase of S. miltiorrhiza (SmCPS is the key enzyme in the first step for transformation of geranylgeranyl diphosphate (GGPP into miltiradiene, which has recently been identified as the precursor of tanshinones. Based on previous gene-to-metabolite network, this study examined the influences of various combined elicitors on the expression of SmCPS and production of tanshinones in S. miltiorrhiza hairy root cultures. Combined elicitors were composed of three classes of elicitors, a heavy metal ion (Ag+, a polysaccharide (yeast extract, YE, and a plant response-signalling compound (methyl jasmonate, MJ. YE + Ag+, Ag+ + MJ, YE + MJ, and YE + Ag+ + MJ were the combinations we tested. The effect of elicitors on the SmCPS expression level was detected by quantitative real-time PCR (qRT-PCR, and the tanshinones accumulation responses to elicitation were analysed by Ultra Performance Liquid Chromatography (UPLC metabolite profiling. Of these combined elicitors, the expression of SmCPS was significantly enhanced by elicitation, especially at 24 h and 36 h. Of four tanshinones detected, the contents of cryptotanshinone and dihydrotanshinone I were enhanced by treatment with YE + Ag+, Ag+ + MJ, and YE + Ag+ + MJ. Our results indicate that appropriate combined elicitors can enhance tanshinones production in hairy root cultures.

  14. Differential effect of purified spruce chitinases and beta-1,3-glucanases on the activity of elicitors from ectomycorrhizal fungi.

    Science.gov (United States)

    Salzer, P; Hübner, B; Sirrenberg, A; Hager, A

    1997-07-01

    Two chitinases (EC 3.2.1.14) and two beta-1,3-glucanases (EC 3.2.1.39) were purified from the culture medium of spruce (Picea abines [L.] Karst.) cells to study their role in modifying elicitors, cell walls, growth, and hyphal morphology of ectomycorrhizal fungi. The 36-kD class I chitinase (isoelectric point [pl] 8.0) and the 28-kD chitinase (pl 8.7) decreased the activity of elicitor preparations from Hebeloma crustuliniforme (Bull. ex Fries.) Quél., Amanita muscaria (L.) Pers., and Suillus variegatus (Sw.: Fr.) O.K., as demonstrated by using the elicitor-induced extracellular alkalinization in spruce cells as a test system. In addition, chitinases released monomeric products from the walls of these ectomycorrhizal fungi. The beta-1,3-glucanases (35 kD, pl 3.7 and 3.9), in contrast, had little influence on the activity of the fungal elicitors and released only from walls of A. muscaria some polymeric products. Furthermore, chitinases alone and in combination with beta-1,3-glucanases had no effect on the growth and morphology of the hyphae. Thus, it is suggested that apoplastic chitinases in the root cortex destroy elicitors from the ectomycorrhizal fungi without damaging the fungus. By this mechanism the host plant could attenuate the elicitor signal and adjust its own defense reactions to a level allowing symbiotic interaction.

  15. Variations in Bioactive Content in Different Tomato Trusses due to Elicitor Effects

    OpenAIRE

    Ávila-Juárez, Luciano; Miranda-Rodríguez, Herminio

    2018-01-01

    The tomato fruit is rich in bioactive compounds with antioxidant activity, the levels of which can vary over time in response to biotic and abiotic factors, including the application of elicitors. We investigated the effects of foliar spray of methyl jasmonate (MeJ), salicylic acid (SA), nitric oxide (NO), and hydrogen peroxide (H2O2) on tomato plants every 15 days until the end of cultivation. We measured the levels of bioactive compounds, antioxidant activity, and physiological parameters i...

  16. Two rice GRAS family genes responsive to N -acetylchitooligosaccharide elicitor are induced by phytoactive gibberellins: evidence for cross-talk between elicitor and gibberellin signaling in rice cells.

    Science.gov (United States)

    Day, R Bradley; Tanabe, Shigeru; Koshioka, Masaji; Mitsui, Toshiaki; Itoh, Hironori; Ueguchi-Tanaka, Miyako; Matsuoka, Makoto; Kaku, Hanae; Shibuya, Naoto; Minami, Eiichi

    2004-01-01

    In this study, we present data showing that two members of the GRAS family of genes from rice, CIGR1 and CIGR2 (chitin-inducible gibberellin-responsive), inducible by the potent elicitor N -acetylchitooligosaccharide (GN), are rapidly induced by exogenous gibberellins. The pattern of mRNA accumulation was dependent on the dose and biological activity of the gibberellins, suggesting that the induction of the genes by gibberellin is mediated by a biological receptor capable of specific recognition and signal transduction upon perception of the phytoactive compounds. Further pharmacological analysis revealed that the CIGR1 and CIGR2 mRNA accumulation by treatment with gibberellin is dependent upon protein phosphorylation/dephosphorylation events. In rice calli derived from slender rice 1, a constitutive gibberellin-responsive mutant, or d1, a mutant deficient in the alpha -subunit of the heterotrimeric G-protein, CIGR1 and CIGR2 were induced by a GN elicitor, yet not by gibberellin. Neither gibberellin nor GN showed related activities in defense or development, respectively. These results strongly suggested that the signal transduction cascade from gibberellin is independent of that from GN, and further implied that CIGR1 and CIGR2 have dual, distinct roles in defense and development.

  17. PAMPs, MAMPs, DAMPs and others: an update on the diversity of plant immunity elicitors

    Directory of Open Access Journals (Sweden)

    Henry, G.

    2012-01-01

    Full Text Available Plants possess a broad array of defenses that could be actively expressed in response of pathogenic organisms or parasites but also following beneficial saprophytic microorganisms recognition. Specifically, there are compounds derived from these organisms and called elicitors that are perceived by the plant to induce a locally or systemically expressed resistance. The understanding of the physiological and biological basis of these induced immunity mechanisms have greatly advanced over the past years but a deeper investigation of the mechanisms underlying the perception of elicitors is essential to develop novel strategies for pest control. The application of chemical and biological stimulators of plant immune defenses in conventional agriculture is expected to increase within the next years. Because of their organic origin and as they provide means for conferring plant protection in a non-transgenic manner, elicitors of plant immunity have a huge potential as biocontrol products. Through this review, we want to illustrate the diversity of compounds identified as stimulators of the plant immune system and describe the mechanisms by which they could be recognized at the plasma membrane level.

  18. The cytoskeleton enhances gene expression in the response to the Harpin elicitor in grapevine

    Science.gov (United States)

    Qiao, Fei; Chang, Xiao-Li; Nick, Peter

    2010-01-01

    The cytoskeleton undergoes dramatic reorganization during plant defence. This response is generally interpreted as part of the cellular repolarization establishing physical barriers against the invading pathogen. To gain insight into the functional significance of cytoskeletal responses for defence, two Vitis cell cultures that differ in their microtubular dynamics were used, and the cytoskeletal response to the elicitor Harpin in parallel to alkalinization of the medium as a fast response, and the activation of defence-related genes were followed. In one cell line derived from the grapevine cultivar ‘Pinot Noir’, microtubules contained mostly tyrosinylated α-tubulin, indicating high microtubular turnover, whereas in another cell line derived from the wild grapevine V. rupestris, the α-tubulin was strongly detyrosinated, indicating low microtubular turnover. The cortical microtubules were disrupted and actin filaments were bundled in both cell lines, but the responses were elevated in V. rupestris as compared with V. vinifera cv. ‘Pinot Noir’. The cytoskeletal responsiveness correlated with elicitor-induced alkalinization and the expression of defence genes. Using resveratrol synthase and stilbene synthase as examples, it could be shown that pharmacological manipulation of microtubules could induce gene expression in the absence of elicitor. These findings are discussed with respect to a role for microtubules as positive regulators of defence-induced gene expression. PMID:20675535

  19. Enhancement of rutin production in Fagopyrum tataricum hairy root cultures with its endophytic fungal elicitors.

    Science.gov (United States)

    Zhao, Jianglin; Xiang, Dabing; Peng, Lianxin; Zou, Liang; Wang, Yuehua; Zhao, Gang

    2014-01-01

    Tartary buckwheat (Fagopyrum tataricum) is a potentially important source of rutin, a natural bioactive flavonoid with antihyperglycemic, antioxidative, antihypertensive, and anti-inflammatory properties. This study examines the effects of endophytic fungi on rutin production in the hairy root cultures of F. tataricum. Without obvious changes in the appearance of the hairy roots, the exogenous fungal mycelia elicitors efficiently stimulated the hairy root growth and rutin biosynthesis, and the stimulation effect was mainly dependent on the mycelia elicitor species, as well as its treatment dose. Two endophytic fungal isolates Fat9 (Fusarium oxysporum) and Fat15 (Alternaria sp.) were screened as promising candidates for promoting F. tataricum hairy root growth and rutin production. With application of polysaccharide (PS) of endophyte Fat9 (200 mg/L), and PS of endophyte Fat15 (100 mg/L) to the hairy root cultures on day 25, the rutin yield was increased to 45.9 mg/L and 47.2 mg/L, respectively. That was about 3.1- to 3.2-fold in comparison with the control level of 14.6 mg/L. Moreover, the present study revealed that the accumulation of rutin resulted from the stimulation of the phenylpropanoid pathway by mycelia PS treatments. This may be an efficient strategy for enhancing rutin production in F. tataricum hairy root culture provided with its endophytic mycelia elicitors.

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

    Science.gov (United States)

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

    2014-11-01

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

  1. Grapevine cell early activation of specific responses to DIMEB, a resveratrol elicitor

    Directory of Open Access Journals (Sweden)

    Pilati Stefania

    2009-08-01

    Full Text Available Abstract Background In response to pathogen attack, grapevine synthesizes phytoalexins belonging to the family of stilbenes. Grapevine cell cultures represent a good model system for studying the basic mechanisms of plant response to biotic and abiotic elicitors. Among these, modified β-cyclodextrins seem to act as true elicitors inducing strong production of the stilbene resveratrol. Results The transcriptome changes of Vitis riparia × Vitis berlandieri grapevine cells in response to the modified β-cyclodextrin, DIMEB, were analyzed 2 and 6 h after treatment using a suppression subtractive hybridization experiment and a microarray analysis respectively. At both time points, we identified a specific set of induced genes belonging to the general phenylpropanoid metabolism, including stilbenes and hydroxycinnamates, and to defence proteins such as PR proteins and chitinases. At 6 h we also observed a down-regulation of the genes involved in cell division and cell-wall loosening. Conclusions We report the first large-scale study of the molecular effects of DIMEB, a resveratrol inducer, on grapevine cell cultures. This molecule seems to mimic a defence elicitor which enhances the physical barriers of the cell, stops cell division and induces phytoalexin synthesis.

  2. Molecular effects of resistance elicitors from biological origin and their potential for crop protection

    Directory of Open Access Journals (Sweden)

    Lea eWiesel

    2014-11-01

    Full Text Available Plants contain a sophisticated innate immune network to prevent pathogenic microbes from gaining access to nutrients and from colonising internal structures. The first layer of inducible response is governed by the plant following the perception of microbe- or modified plant-derived molecules. As the perception of these molecules results in a plant response that can provide efficient resistance towards non-adapted pathogens they can also be described as ‘defence elicitors’. In compatible plant/microbe interactions, adapted microorganisms have means to avoid or disable this resistance response and promote virulence. However, this requires a detailed spatial and temporal response from the invading pathogens. In agricultural practice, treating plants with isolated defence elicitors in the absence of pathogens can promote plant resistance by uncoupling defence activation from the effects of pathogen virulence determinants. The plant responses to plant, bacterial, oomycete or fungal-derived elicitors are not, in all cases, universal and need elucidating prior to the application in agriculture. This review provides an overview of currently known elicitors of biological rather than synthetic origin and places their activity into a molecular context.

  3. EFEKTIFITAS DAYA HAMBAT BAKTERI Streptomyces sp TERHADAP Erwinia sp PENYEBAB PENYAKIT BUSUK REBAH PADA TANAMAN LIDAH BUAYA (Aloe barbadensis Mill

    Directory of Open Access Journals (Sweden)

    SARMILA TASNIM

    2013-05-01

    Full Text Available Streptomyces sp was conducted from December 2010 - June 2011 at the Laboratoryof Microbiology, Biology Department, Math and Science Faculty, UdayanaUniversity Bukit Jimbaran-Bali. Implementation stages of the research consisted ofisolation and testing of the antibiotic activity Streptomyces sp to inhibit growthbacterial pathogens Erwinia sp as a cause of disease in plants fallen foul (Soft rot ofAloe barbadensis Mill.The results of this study have eight isolates of Streptomyces spwith macroscopic and microscopic characters are varied. Furthermore, all isolateswere obtained and then tested against antibiotic activity to inhibit growth the bacteriaErwinia sp. Test results obtained by Streptomyces sp that has the most effective ininhibiting the ability of the bacteria Erwinia sp isolates are Streptomyces sp2for (45%.

  4. The phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) is a pathogen of the pea aphid.

    Science.gov (United States)

    Grenier, Anne-Marie; Duport, Gabrielle; Pagès, Sylvie; Condemine, Guy; Rahbé, Yvan

    2006-03-01

    Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research.

  5. The Phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) Is a Pathogen of the Pea Aphid†

    Science.gov (United States)

    Grenier, Anne-Marie; Duport, Gabrielle; Pagès, Sylvie; Condemine, Guy; Rahbé, Yvan

    2006-01-01

    Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research. PMID:16517643

  6. Molecular characterization and pathogenicity of Erwinia spp. associated with pineapple [Ananas comosus (L.) Merr.] and papaya (Carica papaya L.)

    OpenAIRE

    Ramachandran Kogeethavani; Manaf Uyub Abdul; Zakaria Latiffah

    2015-01-01

    The Erwinia species are well-known pathogens of economic importance in Malaysia causing serious damage to high-value fruit crops that include pineapple [Ananas comosus (L.) Merr.] and papaya (Carica papaya L.).The 16S rRNA sequence using eubacteria fD1 and rP2 primers, identified two bacteria species; Dickeya zeae from pineapple heart rot, and Erwinia mallotivora from papaya dieback. Phylogenetic analysis based on the neighbor-joining method indicated that all the bacterial isolates clustered...

  7. Biology of the fire blight pathogen Erwinia amylovora in oligotrophic environments: survival responses and virulence

    OpenAIRE

    Delgado Santander, Ricardo

    2016-01-01

    Erwinia amylovora es una bacteria fitopatógena de la familia Enterobacteriaceae, responsable del fuego bacteriano de las rosáceas. Los efectos destructivos de este patógeno sobre frutos, flores y prácticamente todos los órganos de las plantas hospedadoras afectadas constituyen una amenaza importante para la producción de pera y manzana, y suponen graves pérdidas económicas anuales en todo el mundo. E. amylovora está clasificada como un organismo de cuarentena en la Unión Europea y en otros pa...

  8. Role of endoglucanases in Erwinia chrysanthemi 3937 virulence on Saintpaulia ionantha.

    Science.gov (United States)

    Boccara, M; Aymeric, J L; Camus, C

    1994-03-01

    The role of endoglucanases (endoglucanases Z and Y) in Erwinia chrysanthemi pathogenicity on Saintpaulia ionantha was assessed by mutagenizing cloned cel genes (celZ and celY) and recombining them with the chromosomal alleles. Strains with an omega interposon in celZ, a deletion in celY, or a double cel mutant were as virulent as the wild-type strain. However, in the strain with a deletion in celY, a delay in the appearance of symptoms was observed, and then maceration progressed as in plants infected with the wild-type strain, suggesting that E. chrysanthemi endoglucanases play a minor role in soft rot disease development.

  9. Molecular detection of Erwinia psidii in guava plants under greenhouse and field conditions

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    Claudênia Ferreira da Silva

    2016-09-01

    Full Text Available ABSTRACT: Erwinia psidii causes bacterial blight of guava ( Psidium guajava , an important disease of this crop in Brazil. The pathogen affects branches and twigs of guava trees, reducing yield significantly. Bacterial dissemination often occurs through contaminated but asymptomatic propagating plant material. The objectives of this research were to evaluate the use of BIO-PCR and conventional PCR to detect E. psidii in inoculated guava plants grown in a greenhouse and in symptomatic and asymptomatic trees from guava orchards. Erwinia psidii strain IBSBF 1576 was inoculated (107CFU mL-1 into young guava shoots and plant tissue was analysed at 0, 5, 10, and 15 days after inoculation. Symptoms were observed after 5 days and all inoculated shoots were PCR positive at all times, by both BIO-PCR and conventional PCR. Under natural infection conditions, 40 samples were tested by BIO-PCR from each of three guava orchards, 20 showing symptoms and 20 asymptomatic. PCR was positive for 58 out of 60 symptomatic samples (96.7% and for 6.7% of asymptomatic samples, showing that the method can be used to detect the pathogen at early stages of infection. This PCR method may be used as a diagnostic tool to assess bacterial survival, dissemination and disease outbreaks.

  10. Survival of Erwinia amylovora in mature apple fruit calyces through the viable but nonculturable (VBNC) state.

    Science.gov (United States)

    Ordax, M; Biosca, E G; Wimalajeewa, S C; López, M M; Marco-Noales, E

    2009-07-01

    Survival of Erwinia amylovora, causal agent of fire blight in pome fruits and other rosaceous plants, was monitored inside mature apples calyces under some storage conditions utilized in fruit. Apple fruit calyces inoculated with two E. amylovora strains and their respective GFP-marked strains were maintained at 26 degrees and 5 degrees C, and the effect of copper treatment was assayed at 0.01 and 0.1 mmol l(-1) CuSO4. In nontreated apples at 26 degrees C, part of the population of E. amylovora survived in the 'viable but nonculturable' (VBNC) state, whereas at 5 degrees C the majority of the population retained culturability. In copper-treated apples, the whole population adopted the VBNC state irrespective of temperature. Regardless of temperature, copper and inoculum dose, VBNC cells recovered culturability and pathogenicity in King's B broth or by host plant passage. Erwinia amylovora survived for at least 35 days in mature apple calyces. Besides, the ability of the pathogen in the VBNC state to regain culturability and pathogenicity suggests that the apple fruit could be a potential carrier of E. amylovora contributing to the spreading of fire blight disease. The risk of E. amylovora dissemination through mature fruit transport, although low, has been demonstrated, and should be considered in pest risk assessments.

  11. Resistance to Erwinia amylovora in immature pears induced by acibenzolar-S-methyl in the orchard

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    A. Mazzucchi

    2009-01-01

    Full Text Available A field trial was carried out to determine whether resistance to Erwinia amylovora could be induced in unripe pears with acibenzolar-S-methyl (ASM, comparing the effectiveness of ASM with a formulate of copper hydroxide. The random block trial was carried out in a commercial pear orchard between June 15 and 29. The treatments were applied in mid-June. Unripe pears were collected from the trees immediately and 1, 2, 4, 7 and 14 days after treatment, and inoculated in the greenhouse within 2–3 hours with a constant dose of a virulent strain of Erwinia amylovora. After inoculation, the pears were stored in a moist chamber at 25±2°C in a greenhouse, and after 8 days the diameter of each surface lesion was measured as well as its width and depth inside the pulp. In the fruits of ASM treated trees there was a reduction in the lesion diameter of the peripheral tissues around the inoculation holes, but not in the deep pulp tissues. Specifically, the symptoms appeared to be milder in the peripheral tissues even 7 and 14 days after treatment with ASM, especially at the lower concentration. The copper compound gave protection to the immature pears for not more than 4 days. These results justify the use of ASM for the protection of unripe fruit in the spring-early summer period to control bacterial fire blight in pear orchards.

  12. Signaling requirements for Erwinia amylovora-induced disease resistance, callose deposition, and cell growth in the nonhost Arabidopsis thaliana

    Science.gov (United States)

    Erwinia amylovora is the causal agent of the fire blight disease in some plants of the Rosaceae family. The nonhost plant Arabidopsis serves as a powerful system to dissect mechanisms of resistance to E. amylovora. Although not yet known to mount gene-for-gene resistance to E. amylovora, we found ...

  13. Symbiotic bacteria (Erwinia sp.) in the gut of Frankliniella occidentalis (Thysanoptera: Thripidae) do not affect its ability to transmit tospovirus

    NARCIS (Netherlands)

    de Vries, E.J.; van de Wetering, F.; van der Hoek, M.M.; Jacobs, G.; Breeuwer, J.A.J.

    2012-01-01

    Tomato spotted wilt virus (TSWV) is one of the most harmful plant viruses and one of its most important vectors is the western flower thrips [Frankliniella occidentalis Pergande (Thysanoptera: Thripidae)]. Recently, we reported the close association of Erwinia sp. gut bacteria with this species of

  14. Conductimetric detection of Pseudomonas syringae pathover pisi in pea seeds and soft rot Erwinia spp. on potato tubers

    NARCIS (Netherlands)

    Fraaije, B.

    1996-01-01


    Pea bacterial blight and potato blackleg are diseases caused by Pseudomonas syringae pv. pisi ( Psp ) and soft rot Erwinia spp., respectively. The primary source of inoculum for these bacteria is

  15. Diet-dependent effects of gut bacteria on their insect host: the symbiosis of Erwinia spec. and western flower thrips

    NARCIS (Netherlands)

    de Vries, E.J.; Jacobs, G.; Sabelis, M.W.; Menken, S.B.J.; Breeuwer, J.A.J.

    2004-01-01

    Studies on bacteria in the gut of insect species are numerous, but their focus is hardly ever on the impact on host performance. We showed earlier that Erwinia bacteria occur in the gut of western flower thrips, most probably acquired during feeding. Here, we investigate whether thrips gain a net

  16. Investigation of Viability of Pantoea agglomerans (Formerly Erwinia herbicola) After Aerosolization From Media Containing Enriching and Coating Chemicals

    Science.gov (United States)

    2008-02-01

    Final Sep) 2005 - Set 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Investigation of Viability of Pantoea agglomerans (Formerly Erwinia DAAD 19-02-D...in this report was authorized under Contract No. DAAD 19- 02-D-0001, Task No. 02149. The work was started in September 2005 and completed in

  17. [Callose accumulation during treatment of tomato (Lycopersicon esculentum L.) cells with biotic elicitors].

    Science.gov (United States)

    Emel'ianov, V I; Kravchuk, Zh N; Poliakovskiĭ, S A; Dmitriev, A P

    2008-01-01

    Time-course of induced accumulation of callose in tomato cells has been studied. Localization of callose in L. esculenthum cells was investigated by fluorescent microscopy technique, and the optimal time for its determination was found. Callose accumulation in tomato cells treated with different biotic elicitors was determined. Nonlinear dependence between callose accumulation and concentration of chitin oligomers (with 3-5 N-acetylglucosamine fragments) was established. Increasing of callose accumulation in tomato cells was proportional to the increase of concentration ofchitin dimer and chitosan in the culture medium.

  18. Effects of various elicitors on the accumulation and secretion of spiroketal enol ether diacetylenes in feverfew hairy root culture

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    Anna Stojakowska

    2011-01-01

    Full Text Available In a hairy root culture of Tanacetum parthenium treated with yeast extract (YE, silver nitrate (AgNO3 and microalgal glycoproteins (MGPS, contents of four spiroketal enol ether type diacetylenes were mesured. The elicitors transiently reduced contents of three constitutive spiroketal enol ethers and selectively enhanced accumulation of cis-C13-spiroketal enol ether epoxide ((E-3,4-epoxy-2-(2,4-hexadiynylidene-1,6-dioxaspiro[4.4]nonane in the roots. The most abundant formation of cis-C13-spiroketal enol ether epoxide was observed after 48-96 h of AgNO3 treatment and 96 h of YE treatment (over 3-fold increase compared with the control. The applied elicitors caused enhanced liberation of cis-C13-spiroketal enol ether epoxide to the culture medium. The results show that diacetylene accumulation pattern in the elicited hairy roots is affected in a similar manner, irrespectively of the elicitor applied.

  19. The specifics of elicitor effect on Triticum aestivum macromorphogenesis under simultaneous lesion by Septoria tritici and Puccinia recondita

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    I.V. Zhuk

    2016-06-01

    Full Text Available Phytopathogenic fungi interrupt the macromorphogenesis of wheat (Triticum aestivum but biotic elicitors stimulate the nonspecific tolerance, growth and development of plant stems. It is shown that oxalic acid as a biotic elicitor and donor of nitric oxide signal molecule (sodium nitroprusside stimulate stem growth in height and last leaves length, as well as grain quantity and productivity both in cv. ‘Poliska 90’ and cv. ‘Stolychna’ under Septoria tritici and Puccinia recondita infection in field trials. It is detected that the degree of infected leaf area decreased in both treated cultivars under Saari-Prescott scale. Cv. ‘Poliska 90’ is more sensitive to both fungal pathogens than cv. ‘Stolychna’, but elicitor influence on its architectonics was no less than on cv. ‘Stolychna’.

  20. Pyrazinecarboxamides as Potential Elicitors of Flavonolignan and Flavonoid Production in Silybum marianum and Ononis arvensis Cultures In Vitro

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    Martin Dolezal

    2011-11-01

    Full Text Available The effect of new synthetic pyrazinecarboxamide derivatives as potential elicitors of flavonolignan and flavonoid production in Silybum marianum and Ononis arvensis cultures in vitro was investigated. Both tested elicitors increased the production of flavonolignans in S. marianum callus and suspension cultures and flavonoids in O. arvensis callus and suspension cultures. Compound I, 5-(2-hydroxybenzoyl-pyrazine-2-carboxamide, has shown to be an effective elicitor of flavonolignans and taxifoline production in Silybum marianum culture in vitro. The maximum content of silydianin (0.11% in S. marianum suspension culture was induced by 24 h elicitor application in concentration of 1.159 × 10−3 mol/L. The maximum content of silymarin complex (0.08% in callus culture of S. marianum was induced by 168 h elicitor application of a concentration 1.159 × 10−4 mol/L, which represents contents of silydianin (0.03%, silychristin (0.01% and isosilybin A (0.04% compared with control. All three tested concentrations of compound II, N-(2-bromo-3-methylphenyl-5-tert-butylpyrazin-2-carboxamide increased the flavonoid production in callus culture of O. arvensis in a statistically significant way. The best elicitation effect of all elicitor concentrations had the weakest c3 concentration (8.36 × 10−6 mol/L after 168 h time of duration. The maximum content of flavonoids (about 5,900% in suspension culture of O. arvensis was induced by 48 h application of c3 concentration (8.36 × 10−6 mol/L.

  1. Responses of Cultured Tobacco Cells to Cryptogein, a Proteinaceous Elicitor from Phytophthora cryptogea1

    Science.gov (United States)

    Blein, Jean-Pierre; Milat, Marie-Louise; Ricci, Pierre

    1991-01-01

    In culture, the phytopathogenic fungus Phytophthora cryptogea secretes a protein which elicits hypersensitive-like necroses and protects tobacco plants against invasion by the pathogen Phytophthora parasitica var. nicotianae. This protein, named cryptogein, has been purified and its amino acid sequence determined. In this work, we studied the effect of cryptogein on tobacco cell suspension cultures. Cryptogein was lethal at about 0.10 micromolar. When added at sublethal doses, it elicited the production of ethylene and phytoalexins. It also induced a rapid increase in pH and conductivity of the extracellular medium without affecting the integrity of the plasma membrane. Cryptogein reduced the fusicoccin-induced acidification of the extracellular medium. The concentration which inhibited the fusicoccin response by 50% was 0.8 nanomolar, while 1 micromolar erythrosine B, an ATPase inhibitor, was needed to produce the same inhibition. However, cryptogein did not inhibit the activity of a purified plasma membrane ATPase. Results of binding studies with whole cells suggested the presence of elicitor-binding sites with a high affinity for cryptogein. The involvement of the plasma membrane during the initial interaction between elicitor and cells is discussed. PMID:16668010

  2. Effect of elicitors and precursors on azadirachtin production in hairy root culture of Azadirachta indica.

    Science.gov (United States)

    Srivastava, Smita; Srivastava, A K

    2014-02-01

    The present study involved strategies for enhancement in in vitro azadirachtin (commercially used biopesticide) production by hairy root cultivation of Azadirachta indica. Improvement in the azadirachtin production via triggering its biosynthetic pathway in plant cells was carried out by the exogenous addition of precursors and elicitors in the growth medium. Among the different abiotic stress inducers (Ag(+), Hg(+2), Co(+2), Cu(+2)) and signal molecules (methyl jasmonate and salicylic acid) tested, salicylic acid at 15 mg l(-1) of concentration was found to enhance the azadirachtin yield in the hairy roots to the maximum (up to 4.95 mg g(-1)). Similarly, among the different biotic elicitors tested (filter-sterilized fungal culture filtrates of Phoma herbarium, Alternaria alternata, Myrothecium sp., Fusarium solani, Curvularia lunata, and Sclerotium rolfsii; yeast extract; and yeast extract carbohydrate fraction), addition of filter-sterilized fungal culture filtrate of C. lunata (1 % v/v) resulted in maximum azadirachtin yield enhancement in hairy root biomass (up to 7.1 mg g(-1)) with respect to the control (3.3 mg g(-1)). Among all the biosynthetic precursors studied (sodium acetate, cholesterol, squalene, isopentynyl pyrophosphate, mavalonic acid lactone, and geranyl pyrophosphate), the overall azadirachtin production (70.42 mg l(-1) in 25 days) was found to be the highest with cholesterol (50 mg l(-1)) addition as an indirect precursor in the medium.

  3. Carrageenans from red seaweeds as promoters of growth and elicitors of defense response in plants

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    Pushp Sheel Shukla

    2016-05-01

    Full Text Available Plants incessantly encounter abiotic and biotic stresses that limit their growth and productivity. However, conversely, plant growth can also be induced by treatments with various abiotic and biotic elicitors. Carrageenans are sulfated linear polysaccharides that represent major cellular constituents of seaweeds belonging to red algae (Rhodophyta. Recent research has unraveled the biological activity of carrageenans and of their oligomeric forms, the oligo carrageenans (OCs, as promoters of plant growth and as elicitors of defense responses against pests and diseases. In this review, we discuss the molecular mechanisms by which carrageenans and OCs mediate plant growth and plant defense responses. Carrageenans and OCs improve plant growth by regulating various metabolic processes such as photosynthesis and ancillary pathways, cell division, purine and pyrimidine synthetic pathways as well as metabolic pathways involved in nitrogen and sulfur assimilation. Carrageenans and OCs also induce plant defense responses against viroids, viruses, bacteria, fungi and insects by modulating the activity of different defense pathways, including salicylate, jasmonate and ethylene signaling pathways. Further studies will likely substantiate the beneficial effects of carrageenans and of OCs on plant growth and plant defense responses and open new avenues for their use in agriculture and horticultural industry.

  4. Additions of precursors and elicitors improve geranylgeraniol production in Croton stellatopilosus callus cultures

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    Juraithip Wungsintaweekul

    2015-02-01

    Full Text Available Strategies for enhancing GGOH production in Croton stellatopilosus callus culture included additions of precursors (sodium acetate-NA, sodium pyruvate-NP, mevalonic acid lactone-MVA and elicitors (methyl jasmonate-MJ, acetylsalicylic acid-ASA, yeast extract-YE. Treated cells were evaluated for their GGOH contents by GC-FID and compared with the nontreated cells as controls. Additions of NA (25 mg/L, NP (50 mg/L and MVA (100 mg/L resulted in an enhancement of GGOH productivity to 0.61 mg/g DW, 0.52 mg/g DW and 0.70 mg/g DW, respectively, compared to the control culture (0.29 mg/g DW. Callus cultures elicited with MJ at 30 mg/L for 24 h stimulated GGOH production to 0.35 mg/g DW compared to the control culture (0.07 mg/g DW. Cells also responded to ASA (20 mg/L, 2 days and YE (0.25 g/L, 4 days and produced GGOH contents of 0.46 mg/g DW and 1.37 mg/g DW, respectively. This study has shown that isoprenoid precursors and conventional elicitors enhanced GGOH production in the C. stellatopilosus callus culture.

  5. Upregulation of isoflavonoids and soluble proteins in edible legumes by light and fungal elicitor treatments.

    Science.gov (United States)

    Lal, Ashish; Warber, Sara; Kirakosyan, Ara; Kaufman, Peter B; Duke, James A

    2003-06-01

    In this study, our working hypothesis was that continuous light and fungal elicitation treatment of legume seedlings would lead to enhanced levels of isoflavonoids and soluble proteins. Based on short-term light and dark treatments, isoflavonoid (genistein, genistin, daidzein, and daidzin) and soluble protein concentrations were significantly upregulated in the "light" environment compared to the "dark" environment for all edible legume species (kudzu vine, soybean, garbanzo bean, fava bean, mung bean, adzuki bean) that were tested. Kudzu seedlings showed the highest levels of both isoflavonoids and soluble proteins after light-elicited upregulation compared to the other legumes analyzed. All legumes showed less up-regulation of isoflavonoid synthesis when treated with Phytophtora sojae fungal elicitor. Oligosaccharide fungal elicitor caused no such upregulation. The findings in this study show that edible legume seedlings have enhanced levels of isoflavonoids and soluble proteins when they are grown in the light compared to the conventional practice of growing such seedlings in the dark. This will clearly result in significant improvement in their nutritive and medicinal value.

  6. Effect of fermentation parameters, elicitors and precursors on camptothecin production from the endophyte Fusarium solani.

    Science.gov (United States)

    Venugopalan, Aarthi; Potunuru, Uma Rani; Dixit, Madhulika; Srivastava, Smita

    2016-04-01

    Volumetric productivity of camptothecin from the suspension culture of the endophyte Fusarium solani was enhanced up to ∼152 fold (from 0.19 μg l(-1) d(-1) to 28.9 μg l(-1) d(-1)) under optimized fermentation conditions including initial pH (6.0), temperature (32 °C) and agitation speed (80 rpm) with (5% (v/v)) ethanol as medium component. Among various elicitors and precursors studied, tryptamine (0.5 mM) as precursor and bovine serum albumin (BSA) (0.075 mM) as an elicitor added on day 6 of the cultivation period resulted in maximum enhancement of camptothecin concentration (up to 4.5 and 3.4-fold, respectively). These leads provide immense scope for further enhancement in camptothecin productivity at bioreactor level. The cytotoxicity analysis of the crude camptothecin extract from the fungal biomass revealed its high effectiveness against colon and mammary gland cancer cell lines. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. The novel elicitor AsES triggers a defense response against Botrytis cinerea in Arabidopsis thaliana.

    Science.gov (United States)

    Hael-Conrad, V; Abou-Mansour, E; Díaz-Ricci, J-C; Métraux, J-P; Serrano, M

    2015-12-01

    AsES (Acremonium strictum Elicitor and Subtilisin) is a novel extracellular elicitor protein produced by the avirulent isolate SS71 of the opportunist strawberry fungal pathogen A. strictum. Here we describe the activity of AsES in the plant-pathogen system Arabidopsis thaliana-Botrytis cinerea. We show that AsES renders A. thaliana plants resistant to the necrotrophic pathogen B. cinerea, both locally and systemically and the defense response observed is dose-dependent. Systemic, but not local resistance is dependent on the length of exposure to AsES. The germination of the spores in vitro was not inhibited by AsES, implying that protection to B. cinerea is due to the induction of the plant defenses. These results were further supported by the findings that AsES differentially affects mutants impaired in the response to salicylic acid, jasmonic acid and ethylene, suggesting that AsES triggers the defense response through these three signaling pathways. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Protein elicitor PemG1 from Magnaporthe grisea induces systemic acquired resistance (SAR) in plants.

    Science.gov (United States)

    Peng, Dong-Hai; Qiu, De-Wen; Ruan, Li-Fang; Zhou, Chen-Fei; Sun, Ming

    2011-10-01

    Elicitors can stimulate defense responses in plants and have become a popular strategy in plant disease control. Previously, we isolated a novel protein elicitor, PemG1, from Magnaporthe grisea. In the present study, PemG1 protein expressed in and purified from Escherichia coli improved resistance of rice and Arabidopsis to bacterial infection, induced transient expression of pathogenesis-related (PR) genes, and increased accumulation of hydrogen peroxide in rice. The effects of PemG1 on disease resistance and PR gene expression were mobilized systemically throughout the rice plant and persisted for more than 28 days. PemG1-induced accumulation of OsPR-1a in rice was prevented by the calcium channel blockers LaCl₃, BAPTA, EGTA, W7, and TFP. Arabidopsis mutants that are insensitive to jasmonic acid (JA) and ethylene showed increased resistance to bacterial infection after PemG1 treatment but PemG1 did not affect resistance of mutants with an impaired salicylic acid (SA) transduction pathway. In rice, PemG1 induced overexpressions of the SA signal-related genes (OsEDS1, OsPAL1, and OsNH1) but not the JA pathway-related genes (OsLOX2 and OsAOS2). Our findings reveal that PemG1 protein can function as an activator of plant disease resistance, and the PemG1-mediated systemic acquired resistance is modulated by SA- and Ca(2+)-related signaling pathways.

  9. The suitability of Finnish climate for fire blight (Erwinia amylovora epidemics on apple

    Directory of Open Access Journals (Sweden)

    Mariela Marinova-Todorova

    2015-03-01

    Full Text Available Fire blight, which is an important disease of apples and pears, has never been detected in continental Finland. In this study the suitability of the Finnish climate for apple blossom blight infections by Erwinia amylovora was evaluated with the epidemiological model MaryblytTM. This was done in fourteen locations, and for two apple cultivars differing in flowering times. Climatic conditions were predicted to be suitable for blossom infections in 18 - 51% of the years, and the annual period of suitable conditions was predicted to last up to two to five days, depending on the location and apple cultivar. The suitable period was predicted to be longer in some locations in central Finland than in those in the southernmost parts of the country. Based on these results the official surveys that are carried out to confirm the absence of fire blight in Finland cannot be targeted only to some parts of the country.

  10. Flavohaemoglobin HmpX: a new pathogenicity determinant in Erwinia chrysanthemi strain 3937.

    Science.gov (United States)

    Favey, S; Labesse, G; Vouille, V; Boccara, M

    1995-04-01

    Unlike wild-type Erwinia chrysanthemi strain 3937, which fully macerates inoculated Saintpaulia plants, HmpX- mutants produce necrotic lesions or no symptoms. The hmpX gene was sequenced and the corresponding protein sequence analysed. We show that HmpX belongs to a family of flavohaemoproteins (HMP), previously identified in two yeasts and in Escherichia coli. Comparisons of protein sequences at the secondary structure level by hydrophobic cluster analysis have shown that HmpX possesses two functional regions, a haemoglobin domain in its N-terminal part and a flavin reductase domain in its C-terminal part. In an HmpX- strain, the synthesis of pectate lyases, which are pathogenicity determinants in E. chrysanthemi, was reduced in conditions of low oxygen tension. Using gus fusion in hmpX, it was shown that hmpX transcription was induced in coculture with tobacco cells. A putative function for HmpX is discussed.

  11. Systemic virulence of Erwinia chrysanthemi 3937 requires a functional iron assimilation system.

    Science.gov (United States)

    Enard, C; Diolez, A; Expert, D

    1988-06-01

    In Erwinia chrysanthemi, conditions of iron starvation initiate production of a catechol-type siderophore and enhance production of three outer membrane polypeptides. Twenty-two mutants affected in the different stages of this iron assimilation system were isolated by mini-Mu insertion mutagenesis. All of them failed to induce systemic soft rot on axenically grown Saintpaulia plants. From the siderophore auxotrophs and the iron uptake mutants, clones having recovered the missing function(s) were isolated by using the in vivo cloning vector pULB113 (RP4::mini-Mu). An R-prime plasmid containing a ca. 35.5-kilobase-pair DNA insert was identified. Restoration of the iron functions restored partially, if not completely, the virulence of the parental strain.

  12. Erwinia amylovora pyrC mutant causes fire blight despite pyrimidine auxotrophy.

    Science.gov (United States)

    Ramos, L S; Sinn, J P; Lehman, B L; Pfeufer, E E; Peter, K A; McNellis, T W

    2015-06-01

    Erwinia amylovora bacteria cause fire blight disease, which affects apple and pear production worldwide. The Erw. amylovora pyrC gene encodes a predicted dihydroorotase enzyme involved in pyrimidine biosynthesis. Here, we discovered that the Erw. amylovora pyrC244::Tn5 mutant was a uracil auxotroph. Unexpectedly, the Erw. amylovora pyrC244::Tn5 mutant grew as well as the wild-type in detached immature apple and pear fruits. Fire blight symptoms caused by the pyrC244::Tn5 mutant in immature apple and pear fruits were attenuated compared to those caused by the wild-type. The pyrC244::Tn5 mutant also caused severe fire blight symptoms in apple tree shoots. A plasmid-borne copy of the wild-type pyrC gene restored prototrophy and symptom induction in apple and pear fruit to the pyrC244::Tn5 mutant. These results suggest that Erw. amylovora can obtain sufficient pyrimidine from the host to support bacterial growth and fire blight disease development, although de novo pyrimidine synthesis by Erw. amylovora is required for full symptom development in fruits. Significance and impact of the study: This study provides information about the fire blight host-pathogen interaction. Although the Erwinia amylovora pyrC mutant was strictly auxotrophic for pyrimidine, it grew as well as the wild-type in immature pear and apple fruits and caused severe fire blight disease in apple trees. This suggests that Erw. amylovora can obtain sufficient pyrimidines from host tissue to support growth and fire blight disease development. This situation contrasts with findings in some human bacterial pathogens, which require de novo pyrimidine synthesis for growth in host blood, for example. © 2015 The Society for Applied Microbiology.

  13. The cyclic AMP receptor protein is the main activator of pectinolysis genes in Erwinia chrysanthemi.

    Science.gov (United States)

    Reverchon, S; Expert, D; Robert-Baudouy, J; Nasser, W

    1997-06-01

    The main virulence factors of the phytopathogenic bacterium Erwinia chrysanthemi are pectinases that cleave pectin, a major constituent of the plant cell wall. Although physiological studies suggested that pectinase production in Erwinia species is subjected to catabolite repression, the direct implication of the cyclic AMP receptor protein (CRP) in this regulation has never been demonstrated. To investigate the role of CRP in pectin catabolism, we cloned the E. chrysanthemi crp gene by complementation of an Escherichia coli crp mutation and then constructed E. chrysanthemi crp mutants by reverse genetics. The carbohydrate fermentation phenotype of the E. chrysanthemi crp mutants is similar to that of an E. coli crp mutant. Furthermore, these mutants are unable to grow on pectin or polygalacturonate as the sole carbon source. Analysis of the nucleotide sequence of the E. chrysanthemi crp gene revealed the presence of a 630-bp open reading frame (ORF) that codes for a protein highly similar to the CRP of E. coli. Using a crp::uidA transcriptional fusion, we demonstrated that the E. chrysanthemi CRP represses its own expression, probably via a mechanism similar to that described for the E. coli crp gene. Moreover, in the E. chrysanthemi crp mutants, expression of pectinase genes (pemA, pelB, pelC, pelD, and pelE) and of genes of the intracellular part of the pectin degradation pathway (ogl, kduI, and kdgT), which are important for inducer formation and transport, is dramatically reduced in induced conditions. In contrast, expression of pelA, which encodes a pectate lyase important for E. chrysanthemi pathogenicity, seems to be negatively regulated by CRP. The E. chrysanthemi crp mutants have greatly decreased maceration capacity in potato tubers, chicory leaves, and celery petioles as well as highly diminished virulence on saintpaulia plants. These findings demonstrate that CRP plays a crucial role in expression of the pectinolysis genes and in the pathogenicity of E

  14. Inhibition of Erwinia chrysanthemi growth to different concentrations of folic acid: possible use of folic acid as bacteriostatic agent and fortifying of Solanum tuberosum potato

    Directory of Open Access Journals (Sweden)

    Andrea Marcelo Correa

    2017-05-01

    Full Text Available Introduction:The enterobacteria of the Erwinia spp genus produce disease in potatoes, which is a tuber of mass consumption. The regulation of DNA methylation can regulate the proliferation of Erwinia in such a way that the concentrations of folic acid may have an effect on the microorganism pathogenic ability. On the other hand, the folic acid prevents the appearance of neural tube defects in humans. Objective: To evaluate folic acid as a bacteriostatic agent of Erwinia and, at the same time, as part of the fortification of mass consumption food such as the potatoes. Materials and methods: The biochemical characterization of the Erwinia chrysanthemi was carried out and its growth compared to different concentrations of folic acid was studied. Results: When increasing the concentrations of the vitamin from 0.3 µg/L up to 6.8 µg/L, the bacterial growth of Erwinia chrysanthemi is inhibited. The vitamin inhibits the growth in cultivation of Erwinia chrysanthemi and acts as a bacteriostatic agent. This aspect is of great importance given that, theoretically, if potatoes were fortified with micro-nutrient, this would act against the infectious agent and, at the same time, contribute to the adequate intake of the vitamin in the general population.

  15. Podridão-mole em plantas de cebolinha causada por Pectobacterium carotovorumsubsp. carotovorum em Roraima Soft rot of bunching onion plants caused by Pectobacterium carotovorumsubsp. carotovorum in Roraima, Brazil

    Directory of Open Access Journals (Sweden)

    Bernardo A. Halfeld-Vieira

    2008-01-01

    Full Text Available A ocorrência de Pectobacterium carotovorum subsp. carotovorum (=Erwinia carotovora subsp. carotovora em cebolinha (Allium fistulosum é relatada pela primeira vez na região norte do Brasil. Até então sua ocorrência estava registrada apenas no Distrito Federal.This is the first report of Pectobacterium carotovorum subsp. carotovorum (=Erwinia carotovora subsp. carotovora causing soft rot of bunching onion (Allium fistulosum plants in Roraima, Brazil. Its occurrence is reported only in Distrito Federal.

  16. Disulfide bond structure of the AVR9 elicitor of the fungal tomato pathogen Cladosporium fulvum: Evidence for a cysteine knot

    NARCIS (Netherlands)

    Hooven, van den H.W.; Burg, van den H.A.; Vossen, J.P.M.J.; Boeren, S.; Wit, de P.J.G.M.; Vervoort, J.J.M.

    2001-01-01

    Disease resistance in plants is commonly activated by the product of an avirulence (Avr) gene of a pathogen after interaction with the product of a matching resistance (R) gene in the host. In susceptible plants, Avr products might function as virulence or pathogenicity factors. The AVR9 elicitor

  17. Cell surfaces in plant-microorganism interactions : v. Elicitors of fungal and of plant origin trigger the synthesis of ethylene and of cell wall hydroxyproline-rich glycoprotein in plants.

    Science.gov (United States)

    Roby, D; Toppan, A; Esquerré-Tugayé, M T

    1985-03-01

    Treatment of melon hypocotyls or petioles with an elicitor from Colletotrichum lagenarium, a fungal pathogen of melons, causes an initial transitory inhibition of protein synthesis and, after 18 hours, induces the synthesis of a plant cell wall hydroxyproline-rich glycoprotein (HRGP). Microgram amounts of elicitor are sufficient for maximum elicitation of HRGP when the elicitor is injected into hypocotyls. High elicitor concentrations have a strong inhibitory effect on total protein synthesis. Ethylene is increased early in elicitor-treated plant material, and may be involved in HRGP elicitation. In the presence of aminoethoxyvinylglycine, an inhibitor of ethylene synthesis, both elicitor-induced ethylene and elicitor-induced HRGP are inhibited. On the other hand, 1-aminocyclopropane-1-carboxylic acid, the direct precursor of ethylene, triggers the synthesis of HRGP to the same extent as the elicitor of C. lagenarium, and partly restores in elicitor-treated petioles the synthesis of ethylene and of HRGP after previous inhibition by aminoethoxyvinylglycine. Elicitation of HRGP occurs in other systems, such as soybeans when inoculated with an elicitor from Phytophtora megasperma f. sp. glycinea, and when melons are incubated with an elicitor isolated from their cell walls.

  18. Molecular characterization and pathogenicity of Erwinia spp. associated with pineapple [Ananas comosus (L. Merr.] and papaya (Carica papaya L.

    Directory of Open Access Journals (Sweden)

    Ramachandran Kogeethavani

    2015-12-01

    Full Text Available The Erwinia species are well-known pathogens of economic importance in Malaysia causing serious damage to high-value fruit crops that include pineapple [Ananas comosus (L. Merr.] and papaya (Carica papaya L..The 16S rRNA sequence using eubacteria fD1 and rP2 primers, identified two bacteria species; Dickeya zeae from pineapple heart rot, and Erwinia mallotivora from papaya dieback. Phylogenetic analysis based on the neighbor-joining method indicated that all the bacterial isolates clustered in their own taxa and formed monophyletic clades. From the pathogenicity test, all isolates of D. zeae and E. mallotivora showed pathogenic reactions on their respective host plants. Genetic variability of these isolates was assessed using repetitive sequence-based PCR (rep-PCR fingerprinting. The results indicated interspecies, and intraspecies variation in both species’ isolates. There were more polymorphic bands shown by rep-PCR fingerprints than enterobacterial repetitive intergenic consensus (ERIC and BOX- PCRs, however both species’ isolates produced distinguishable banding patterns. Unweighted pair-group method with arithmetic averages (UPGMA cluster analysis indicated that all Dickeya and Erwinia isolates from the same species were grouped in the same main cluster. Similarity among the isolates ranged from 77 to 99%. Sequencing of 16S rRNA using eubacteria fD1 and rP2 primers, and rep-PCR fingerprinting revealed diversity among Dickeya and Erwinia isolates. But this method appears to be reliable for discriminating isolates from pineapple heart rot and papaya dieback.

  19. 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.

  20. A fungal protein elicitor PevD1 induces Verticillium wilt resistance in cotton.

    Science.gov (United States)

    Bu, Bingwu; Qiu, Dewen; Zeng, Hongmei; Guo, Lihua; Yuan, Jingjing; Yang, Xiufen

    2014-03-01

    We found that the elicitor PevD1 triggered innate immunity in cotton, which plays an important role in future cotton wilt disease control. Elicitors can induce defense responses in plants and improve pathogen resistance. PevD1 is a secreted protein from Verticillium dahliae and activates the hypersensitive response and systemic acquired resistance to tobacco mosaic virus in tobacco plants. To investigate the PevD1-induced disease resistance mechanisms in cotton (Gossypium hirsutum), we report that Escherichia coli expressing PevD1 enhanced cotton resistance and the defense response to the fungal pathogen V. dahliae. The results showed that recombinant PevD1 improved cotton resistance when infiltrated at a concentration as low as 4 μg ml(-1), and the highest disease reduction was 38.16 % on the 15th day post V. dahliae inoculation. This protein was able to systemically induce hydrogen peroxide production, nitric oxide generation, lignin deposition, vessel reinforcement and defense enzymes, including phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase. PevD1 also enhanced the expression of three pathogenesis-related genes, namely, β-1,3-glucanase, chitinase, and cadinene synthase, and three key genes, PAL, C4H1, and 4CL, from the cotton defense phenylpropanoid metabolism pathway. Our results demonstrated that PevD1 acted as an effector in cotton and V. dahliae interactions and triggered innate immunity in cotton, resulting in the upregulation of defense-related genes, metabolic substance deposition and cell wall modifications. PevD1 is a candidate plant defense activator for cotton wilt disease control.

  1. Survival Strategy of Erwinia amylovora against Copper: Induction of the Viable-but-Nonculturable State

    Science.gov (United States)

    Ordax, Mónica; Marco-Noales, Ester; López, María M.; Biosca, Elena G.

    2006-01-01

    Copper compounds, widely used to control plant-pathogenic bacteria, have traditionally been employed against fire blight, caused by Erwinia amylovora. However, recent studies have shown that some phytopathogenic bacteria enter into the viable-but-nonculturable (VBNC) state in the presence of copper. To determine whether copper kills E. amylovora or induces the VBNC state, a mineral medium without copper or supplemented with 0.005, 0.01, or 0.05 mM Cu2+ was inoculated with 107 CFU/ml of this bacterium and monitored over 9 months. Total and viable cell counts were determined by epifluorescence microscopy using the LIVE/DEAD kit and by flow cytometry with 5-cyano-2,3-ditolyl tetrazolium chloride and SYTO 13. Culturable cells were counted on King's B nonselective solid medium. Changes in the bacterial morphology in the presence of copper were observed by scanning electron microscopy. E. amylovora entered into the VBNC state at all three copper concentrations assayed, much faster when the copper concentration increased. The addition of different agents which complex copper allowed the resuscitation (restoration of culturability) of copper-induced VBNC cells. Finally, copper-induced VBNC cells were virulent only for the first 5 days, while resuscitated cells always regained their pathogenicity on immature fruits over 9 months. These results have shown, for the first time, the induction of the VBNC state in E. amylovora as a survival strategy against copper. PMID:16672494

  2. High-throughput screening of Erwinia chrysanthemi pectin methylesterase variants using carbohydrate microarrays.

    Science.gov (United States)

    Øbro, Jens; Sørensen, Iben; Derkx, Patrick; Madsen, Christian T; Drews, Martin; Willer, Martin; Mikkelsen, Jørn D; Willats, William G T

    2009-04-01

    Pectin methylesterases (PMEs) catalyse the removal of methyl esters from the homogalacturonan (HG) backbone domain of pectin, a ubiquitous polysaccharide in plant cell walls. The degree of methyl esterification (DE) impacts upon the functional properties of HG within cell walls and plants produce numerous PMEs that act upon HG in muro. Many microbial plant pathogens also produce PMEs, the activity of which renders HG more susceptible to cleavage by pectin lyase and polygalacturonase enzymes and hence aids cell wall degradation. We have developed a novel microarray-based approach to investigate the activity of a series of variant enzymes based on the PME from the important pathogen Erwinia chrysanthemi. A library of 99 E. chrysanthemi PME mutants was created in which seven amino acids were altered by various different substitutions. Each mutant PME was incubated with a highly methyl esterified lime pectin substrate and, after digestion the enzyme/substrate mixtures were printed as microarrays. The loss of activity that resulted from certain mutations was detected by probing arrays with a mAb (JIM7) that preferentially binds to HG with a relatively high DE. Active PMEs therefore resulted in diminished JIM7 binding to the lime pectin substrate, whereas inactive PMEs did not. Our findings demonstrate the feasibility of our approach for rapidly testing the effects on PME activity of substituting a wide variety of amino acids at different positions.

  3. Erwinia amylovora – the Causal Agent of Root Collar Necrosis of Apple Trees

    Directory of Open Access Journals (Sweden)

    Veljko Gavrilović

    2008-01-01

    Full Text Available A large-scale outbreak of fire blight symptoms caused by Erwinia amylovora was recorded in pome fruit trees during 2007. In addition to fruit necrosis and shoot blight as the typical disease symptoms, dark purple necrosis was observed in the root collar area girdling the trunk just above the ground and thus withering the whole apple tree. Since similar symptoms on apple trees could be caused by E. amylovora or one of several phytopathogenic fungi of the genera Phomopsis and Phytophthora, an investigation was conducted to identify the causal agent of this disease. Levan-producing, nonfluorescent bacteria were isolated from diseased samples. The isolated strains produced HR in tobacco leaves and necrosis of artificially inoculated, immature pear fruits, followed by oozing of bacterial exudate, a characterisitic of E. amylovora. Based on the results of pathogenicity tests, biochemical characteristics, ELISA test and PCR analysis, it was confirmed that the investigated strainsbelonged to E. amylovora, causing the root collar necrosis of apple trees as an atypical symptom of this bacterium in Serbia. The explanation of this symptom may be that the vegetative rootstocks were infected with E. amylovora. Therefore, the development of diagnostic protocols for detection of E. amylovora in apple rootstock is very important for health inspections of planting materials.

  4. Fire blight (Erwinia amylovora [Burrill] Winslow in Morocco: importance, geographical distribution and characterization

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    M'Barek FATMI

    2011-09-01

    Full Text Available Fire blight, caused by Erwinia amylovora, was detected in Morocco in 2006 and has spread rapidly throughout the most important pome fruit-producing regions. Surveys were carried out in 2009 in the main pome fruit-growing areas in Morocco to evaluate the current situation of the disease in the country, particularly in the El Hajeb region, where important losses due to this pathogen were recorded. Samples showing symptoms associated with the disease were collected from affected apple (Malus domestica, pear (Pyrus communis and quince (Cydonia oblonga trees and processed for the isolation and purification of the causal agent. Other isolates collected in the period 2006–2008 were also included in this study. All the isolates were identified to genus and species levels using morphological, biochemical and serological tests. Confi rmation tests were carried out using classical PCR and Real-time PCR. Forty eight Moroccan isolates were confirmed to belong to E. amylovora. Fingerprinting methods (rep-PCR and fAFLP showed a diversity of the isolates and resulted in grouping them in four separate subgroups. This study suggests that Moroccan isolates of  E. amylovora have multiple geographical origins.

  5. Medfly Ceratitis capitata as Potential Vector for Fire Blight Pathogen Erwinia amylovora: Survival and Transmission.

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    Mónica Ordax

    Full Text Available Monitoring the ability of bacterial plant pathogens to survive in insects is required for elucidating unknown aspects of their epidemiology and for designing appropriate control strategies. Erwinia amylovora is a plant pathogenic bacterium that causes fire blight, a devastating disease in apple and pear commercial orchards. Studies on fire blight spread by insects have mainly focused on pollinating agents, such as honeybees. However, the Mediterranean fruit fly (medfly Ceratitis capitata (Diptera: Tephritidae, one of the most damaging fruit pests worldwide, is also common in pome fruit orchards. The main objective of the study was to investigate whether E. amylovora can survive and be transmitted by the medfly. Our experimental results show: i E. amylovora can survive for at least 8 days inside the digestive tract of the medfly and until 28 days on its external surface, and ii medflies are able to transmit the bacteria from inoculated apples to both detached shoots and pear plants, being the pathogen recovered from lesions in both cases. This is the first report on E. amylovora internalization and survival in/on C. capitata, as well as the experimental transmission of the fire blight pathogen by this insect. Our results suggest that medfly can act as a potential vector for E. amylovora, and expand our knowledge on the possible role of these and other insects in its life cycle.

  6. Medfly Ceratitis capitata as Potential Vector for Fire Blight Pathogen Erwinia amylovora: Survival and Transmission

    Science.gov (United States)

    Ordax, Mónica; Piquer-Salcedo, Jaime E.; Santander, Ricardo D.; Sabater-Muñoz, Beatriz; Biosca, Elena G.; López, María M.; Marco-Noales, Ester

    2015-01-01

    Monitoring the ability of bacterial plant pathogens to survive in insects is required for elucidating unknown aspects of their epidemiology and for designing appropriate control strategies. Erwinia amylovora is a plant pathogenic bacterium that causes fire blight, a devastating disease in apple and pear commercial orchards. Studies on fire blight spread by insects have mainly focused on pollinating agents, such as honeybees. However, the Mediterranean fruit fly (medfly) Ceratitis capitata (Diptera: Tephritidae), one of the most damaging fruit pests worldwide, is also common in pome fruit orchards. The main objective of the study was to investigate whether E. amylovora can survive and be transmitted by the medfly. Our experimental results show: i) E. amylovora can survive for at least 8 days inside the digestive tract of the medfly and until 28 days on its external surface, and ii) medflies are able to transmit the bacteria from inoculated apples to both detached shoots and pear plants, being the pathogen recovered from lesions in both cases. This is the first report on E. amylovora internalization and survival in/on C. capitata, as well as the experimental transmission of the fire blight pathogen by this insect. Our results suggest that medfly can act as a potential vector for E. amylovora, and expand our knowledge on the possible role of these and other insects in its life cycle. PMID:25978369

  7. Kinetic Properties of α-Galactosidase and the Localization of Total Proteins in Erwinia chrysanthemi

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    John Morgan Brand

    2004-01-01

    Full Text Available Erwinia chrysanthemi is an enterobacterium that causes soft-rot in plants in general, resulting in enormous economic losses annually. For the pathogen to survive in the host plant, it has to use the readily assimilable compounds from the host fluids and degrade the host tissue. To accomplish this, E. chrysanthemi produces several extracellular and intracellular enzymes. Among the intracellular enzymes there is a special digestive class, the galactosidases, which can be either periplasmic or cytoplasmic. α-Galactosidase is known to degrade melibiose and raffinose into glucose and galactose, and into galactose and sucrose respectively. The aim of the present study was to investigate the kinetic properties of α-galactosidase in E. chrysanthemi, and the localization of total proteins, after culturing it in the presence of raffinose and melibiose. The α-galactosidase that degrades melibiose seems to be the same enzyme that is also responsible for the breakdown of raffinose in E. chrysanthemi. It is localized mainly in the cytoplasm with a fraction of between 2.4 and 5.4 % localized in the periplasm. The majority of E. chrysanthemi proteins have cytoplasmic localization.

  8. Characterization of the Erwinia chrysanthemi gan Locus, Involved in Galactan Catabolism▿ †

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    Delangle, Aurélie; Prouvost, Anne-France; Cogez, Virginie; Bohin, Jean-Pierre; Lacroix, Jean-Marie; Cotte-Pattat, Nicole Hugouvieux

    2007-01-01

    β-1,4-Galactan is a major component of the ramified regions of pectin. Analysis of the genome of the plant pathogenic bacteria Erwinia chrysanthemi revealed the presence of a cluster of eight genes encoding proteins potentially involved in galactan utilization. The predicted transport system would comprise a specific porin GanL and an ABC transporter made of four proteins, GanFGK2. Degradation of galactans would be catalyzed by the periplasmic 1,4-β-endogalactanase GanA, which released oligogalactans from trimer to hexamer. After their transport through the inner membrane, oligogalactans would be degraded into galactose by the cytoplasmic 1,4-β-exogalactanase GanB. Mutants affected for the porin or endogalactanase were unable to grow on galactans, but they grew on galactose and on a mixture of galactotriose, galactotetraose, galactopentaose, and galactohexaose. Mutants affected for the periplasmic galactan binding protein, the transporter ATPase, or the exogalactanase were only able to grow on galactose. Thus, the phenotypes of these mutants confirmed the functionality of the gan locus in transport and catabolism of galactans. These mutations did not affect the virulence of E. chrysanthemi on chicory leaves, potato tubers, or Saintpaulia ionantha, suggesting an accessory role of galactan utilization in the bacterial pathogeny. PMID:17644603

  9. Characterization and virulence properties of Erwinia chrysanthemi lipopolysaccharide-defective, phi EC2-resistant mutants.

    Science.gov (United States)

    Schoonejans, E; Expert, D; Toussaint, A

    1987-09-01

    Outer membrane alterations were characterized in spontaneous mutants of the Erwinia chrysanthemi 3937jRH, which were selected for resistance to bacteriophage phi EC2. All but one of the mutants analyzed were affected in their lipopolysaccharide (LPS) structure, lacking the entire heterogeneous region of apparent high molecular weight present in the wild-type E. chrysanthemi LPS. At least two 3937jRH mutants, one selected as phi EC2 resistant (RH6065) and the other previously selected (D. Expert and A. Toussaint, J. Bacteriol. 163:221-227, 1985) as bacteriocin resistant (R1456), were cross-resistant to bacteriophage Mu and had rough LPSs with an altered core structure. Two phi EC2r mutants (RH6053 and RH6065) were most severely affected in their outer membrane integrity and also lost their virulence on saintpaulia plants, although they still possessed normal extracellular levels of pectinolytic and cellulolytic activities. The two Mur mutants RH6065 and R1456 were also able to induce systemic resistance in the challenged plant. All the other phi EC2r mutants retained the virulence of 393jRH.

  10. Iron Deficiency Induced by Chrysobactin in Saintpaulia Leaves Inoculated with Erwinia chrysanthemi.

    Science.gov (United States)

    Neema, C.; Laulhere, J. P.; Expert, D.

    1993-07-01

    In this communication, we examine the fate of iron during soft rot pathogenesis caused by Erwinia chrysanthemi on its host, Saintpaulia ionantha. The spread of soft rot caused by this enterobacterium was previously shown to depend on a functional genetic locus encoding a high-affinity iron assimilation system involving the catechol-type siderophore chrysobactin. Leaf intercellular fluid from healthy plants was analyzed with regard to the iron content and its availability for bacterial growth. It was compared to the fluid from diseased plants for the presence of strong iron ligands, using a new approach based on the iron-binding property of an ion-exchange resin. Further characterization allowed the identification of chrysobactin in diseased tissues, thus providing the first evidence for the external release of a microbial siderophore during pathogenesis. Competition for nutritional iron was also studied through a plant-bacterial cell system: iron incorporated into plant ferritin appeared to be considerably reduced in bacteria-treated suspension soybean cells. The same effect was visualized during treatment of soybean cells with axenic leaf intercellular fluid from E. chrysanthemi-inoculated saintpaulia leaves or with chrysobactin.

  11. The PecT repressor coregulates synthesis of exopolysaccharides and virulence factors in Erwinia chrysanthemi.

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    Condemine, G; Castillo, A; Passeri, F; Enard, C

    1999-01-01

    Erwinia chrysanthemi 3937 synthesizes an exopolysaccharide (EPS) composed of rhamnose, galactose, and galacturonic acid. Fourteen transcriptional fusions in genes required for EPS synthesis, named eps, were obtained by Tn5-B21 mutagenesis. Eleven of them are clustered on the chromosome and are repressed by PecT, a regulator of pectate lyase synthesis. In addition, expression of these fusions is repressed by the catabolite regulatory protein, CRP, and induced in low osmolarity medium. The three other mutations are located in genes that are not regulated by pecT. A 13-kb DNA fragment containing pecT-regulated eps genes has been cloned. All the genes identified on this fragment are transcribed in the same orientation and could form a large operon. The promoter region of this operon has been sequenced. It contains a JUMP-start sequence, a sequence required for the expression of polysaccharide-associated operons. E. chrysanthemi 3937 produces a systemic soft rot on its host Saintpaulia ionantha. An eps mutant was less efficient than the wild-type strain in initiating a maceration symptom, suggesting that production of EPS is required for the full expression of the E. chrysanthemi virulence.

  12. Characterization of the Erwinia chrysanthemi Gan locus, involved in galactan catabolism.

    Science.gov (United States)

    Delangle, Aurélie; Prouvost, Anne-France; Cogez, Virginie; Bohin, Jean-Pierre; Lacroix, Jean-Marie; Cotte-Pattat, Nicole Hugouvieux

    2007-10-01

    beta-1,4-Galactan is a major component of the ramified regions of pectin. Analysis of the genome of the plant pathogenic bacteria Erwinia chrysanthemi revealed the presence of a cluster of eight genes encoding proteins potentially involved in galactan utilization. The predicted transport system would comprise a specific porin GanL and an ABC transporter made of four proteins, GanFGK(2). Degradation of galactans would be catalyzed by the periplasmic 1,4-beta-endogalactanase GanA, which released oligogalactans from trimer to hexamer. After their transport through the inner membrane, oligogalactans would be degraded into galactose by the cytoplasmic 1,4-beta-exogalactanase GanB. Mutants affected for the porin or endogalactanase were unable to grow on galactans, but they grew on galactose and on a mixture of galactotriose, galactotetraose, galactopentaose, and galactohexaose. Mutants affected for the periplasmic galactan binding protein, the transporter ATPase, or the exogalactanase were only able to grow on galactose. Thus, the phenotypes of these mutants confirmed the functionality of the gan locus in transport and catabolism of galactans. These mutations did not affect the virulence of E. chrysanthemi on chicory leaves, potato tubers, or Saintpaulia ionantha, suggesting an accessory role of galactan utilization in the bacterial pathogeny.

  13. Sucrose isomerase and its mutants from Erwinia rhapontici can synthesise α-arbutin.

    Science.gov (United States)

    Zhou, Xing; Zheng, Yuantao; Wei, Xingming; Yang, Kedi; Yang, Xiangkai; Wang, Yuting; Xu, Liming; Du, Liqin; Huang, Ribo

    2011-10-01

    Sucrose isomerase (SI) from Erwinia rhapontici is an intramolecular isomerase that is normally used to synthesise isomaltulose from sucrose by a mechanism of intramolecular transglycosylation. In this study, it was found that SI could synthesise α-arbutin using hydroquinone and sucrose as substrates, via an intermolecular transglycosylation reaction. Five phenylalanine residues (F185, F186, F205, F297, and F321) in the catalytic pocket of SI were chosen for sitedirected mutagenesis. Mutants F185I, F321I, and F321W, whose hydrolytic activities were enhanced after the mutation, could synthesise α-arbutin through intermolecular transglycosylation with a more than two-fold increase in the molar transfer ratio compared with wild type SI. The F297A mutant showed a strong ability to synthesise a novel α-arbutin derivative and a four-fold increase in its specific activity for intermolecular transglycosylation over the wild type. Our findings may lead to a new way to synthesise novel glucoside products such as α-arbutin derivatives by simply manipulating the Phe residues in the catalytic pocket. From the structure superposition, our strategy of manipulating these Phe residues may be applicable to other similar transglycosylating enzymes.

  14. Catalase and alternative oxidase cooperatively regulate programmed cell death induced by beta-glucan elicitor in potato suspension cultures.

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    Mizuno, Masashi; Tada, Yasuomi; Uchii, Kimitaka; Kawakami, Sachiko; Mayama, Shigeyuki

    2005-04-01

    In potato (Solanum tuberosum L.) suspension cells, the expression of the gene encoding alternative oxidase (AOX) and H2O2 accumulation were induced by treatment with beta-glucan elicitor. The inhibition of catalase activity enhanced both AOX mRNA expression and the production of H2O2, whereas the ascorbate peroxidase inhibitor did not have any effect on these responses. Simultaneous inhibition of catalase and AOX activities in elicited cells dramatically increased H2O2 accumulation, leading to the disruption of mitochondrial membrane potential (deltapsi(m)) and programmed cell death (PCD). The results demonstrate, for the first time, that not only AOX but also catalase plays a central role in the suppression of mitochondrial deltapsi(m) breakdown and PCD induced by beta-glucan elicitor.

  15. Separation and identification of candidate protein elicitors from the cultivation medium of Leptosphaeria maculans inducing resistance in Brassica napus.

    Science.gov (United States)

    Nováková, Miroslava; Kim, Phuong Dinh; Šašek, Vladimír; Burketová, Lenka; Jindřichová, Barbora; Šantrůček, Jiří; Valentová, Olga

    2016-07-08

    The Dothideomycete Leptosphaeria maculans, a worldwide fungal pathogen of oilseed rape (Brassica napus), secretes a broad spectrum of molecules into the cultivation medium during growth in vitro. Here, candidate elicitor molecules, which induce resistance in B. napus to L. maculans, were identified in the cultivation medium. The elicitation activity was indicated by increased transcription of pathogenesis-related gene 1 (PR1) and enhanced resistance of B. napus plants to the invasion of L. maculans. The elicitation activity was significantly lowered when the cultivation medium was heated to 80°C. Active components were further characterized by specific cleavage with the proteolytic enzymes trypsin and proteinase K and with glycosidases α-amylase and β-glucanase. The elicitor activity was eliminated by proteolytic digestion while glycosidases had no effect. The filtered medium was fractionated by either ion-exchange chromatography or isoelectric focusing. Mass spectrometry analysis of the most active fractions obtained by both separation procedures revealed predominantly enzymes that can be involved in the degradation of plant cell wall polysaccharides. This is the first study searching for L. maculans-specific secreted elicitors with a potential to be used as defense-activating agents in the protection of B. napus against L. maculans in agriculture. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:918-928, 2016. © 2016 American Institute of Chemical Engineers.

  16. Controle de Bipolaris sorokiniana e rendimento de grãos em cevada após aplicação de elicitores e fungicida = Bipolaris sorokiniana control and grain yield in barley after application of elicitors and fungicide

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    Noemir Antoniazzi

    2007-12-01

    Full Text Available A mancha marrom causada pelo fungo Bipolaris sorokiniana é considerada um dos problemas fitossanitários mais importantes na cevada provocando reduções na produtividade e prejuízos na qualidade cervejeira. O objetivo deste trabalho foi avaliar o efeito dos elicitores goma xantana e alicina e do fungicida epoxiconazole + piraclostrobina no controle da mancha marrom em cevada cervejeira, cultivar BRS 195 em dois ciclos de cultivo. O experimento foi conduzido na Fundação Agrária de Pesquisa Agropecuária (FAPA, em Guarapuava, Estado do Paraná, em delineamento de blocos ao acaso, comquatro repetições. A aplicação de elicitores e fungicida resultou em maior peso de mil sementes, sem interferir no teor de proteínas e na classificação comercial. O rendimento de grãos foi superior após duas ou três aplicações de alicina. A incidência e severidade de B.sorokiniana nas folhas de plantas tratadas com elicitores foram semelhantes àquelas com fungicida.The disease spot blotch, caused by the fungi Bipolaris sorokiniana, is considered one of the most important phytosanitary problems ofbarley crop resulting on low productivity and damage on beer quality. The objective of this work was to evaluate the effect of the elicitors xanthan gum and alicin and fungicide epoxiconazole + pyraclostrobin on spot blotch control of barley cultivar BRS 195 during two cultivation cycles. The experiment was carried out at Fundação Agrária de Pesquisa Agropecuária (FAPA, Guarapuava, state of Paraná. The experimental design was in completely randomized blocks, with four replications. Treatment of barley plants withelicitors and fungicide resulted in higher thousand-seed weight without interfering on protein content and commercial classification. The grain yield increased after two or three alicin treatments. Bipolaris sorokiniana incidence and severety on the leaves of plants treated with elicitors were similar to those treated with fungicide.

  17. Production of glucosyltransferase by Erwinia sp. using experimental design and response surface methodology Produção de glicosiltransferase por Erwinia sp. utilizando planejamento experimental e metodologia de superfície de resposta

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    Haroldo Yukio Kawaguti

    2005-09-01

    Full Text Available Glucosyltransferase produced by strain Erwinia sp. is an intracellular enzyme that catalyzes the formation of isomaltulose from sucrose. Isomaltulose is a non-cariogenic reducing dissacharide commercially used in foods. Response surface methodology and 2³-factorial central composite design were employed to optimize a fermentation medium for the production of glucosyltransferase by Erwinia sp. in shaken flasks at 200 rpm and 30ºC. The three variables involved in this study were sugar cane molasses (SCM, corn steep liquor (CSL and yeast extract Prodex Lac SD (YEP. The statistical analysis of the results showed that, in the range studied, all the factors had a significant effect on glucosyltransferase production and the optimum medium composition for enzyme production was (in g l-1 SCM-100, CSL-60 and YEP-8, which lead to a glucosyltransferase activity of 6.65 U mL-1.A glicosiltransferase obtida pela linhagem Erwinia sp. é uma enzima intracelular que catalisa a conversão de sacarose em isomaltulose. A isomaltulose é um dissacarídeo redutor, não cariogênico e comercialmente utilizado em alimentos como substituto da sacarose. A metodologia de superfície de resposta e planejamento fatorial composto central-2³ foram utilizados para otimizar o meio de cultivo para a produção de glicosiltransferase de Erwinia sp. em frascos sob agitação a 200 rpm e 30ºC. As três variáveis independentes envolvidas no estudo foram o melaço de cana de açúcar, a água de maceração de milho e o extrato de levedura Prodex Lac SD. As análises estatísticas dos resultados mostraram que, dentro da faixa estudada das concentrações dos componentes de meio de cultivo, todas as variáveis apresentaram efeito significativo na produção de glicosiltransferase. O meio de cultivo otimizado foi composto de 100 gL-1 de melaço de cana de açúcar, 60 gL-1 de água de maceração de milho e 8 gL-1 de extrato de levedura Prodex Lac SD, apresentando atividade de

  18. Azadirachtin biosynthesis induction in Azadirachta indica A. Juss cotyledonary calli with elicitor agents

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    Marcelo Rodrigues

    2014-04-01

    Full Text Available The use of cell and plant tissues culture techniques to produce economically important active metabolites has been growing. Among these substances, azadirachtin (AZA, produced by the neem tree (Azadirachta indica, has received considerable attention due to its bioinsecticide action. The main goal of this work was to analyze the AZA levels in neem cotyledonary calli. The calli were grown in agitated Woody Plant Medium (WPM liquid medium, supplemented with glucose (Gl, hydrolyzed casein (HC and methyl jasmonate (MeJ as elicitor agent. An interaction was observed between these substances, depending on in vitro cultivation time with orbital agitation. The highest concentrations (average of 0.2470 µg g-1 of AZA were produced in the first and second weeks of culture when the cell mass was grown in a medium with 2% Gl v/v, 500 mg L-1 HC and 100 µM of MeJ. This corresponded to approximately 57% of the AZA content stored in the donor plants seeds, used as a source of explants to induce in vitro callus formation. It was concluded that the nutrition, as well as the concentration of MeJ as signal transduction of secondary metabolism in neem cells, might influence the AZA content produced in vitro.

  19. Substituted N-Phenylpyrazine-2-carboxamides, Their Synthesis and Evaluation as Herbicides and Abiotic Elicitors

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    Katarína Kráľová

    2007-12-01

    Full Text Available The condensation of substituted pyrazine-2-carboxylic acid chlorides with ring-substituted anilines yielded five substituted pyrazine-2-carboxylic acid amides. Thesynthesis, and analytical, lipophilicity and biological data of the newly synthesizedcompounds are presented in this paper. The photosynthesis inhibition, antialgal activityand the effect of a series of pyrazine derivatives as abiotic elicitors on the accumulation offlavonoids in a callus culture of Ononis arvensis (L. were investigated. The most activeinhibitor of the oxygen evolution rate in spinach chloroplasts was 6-chloro-pyrazine-2-carboxylic acid (3-iodo-4-methylphenyl-amide (2, IC50 = 51.0 μmol·L-1. The highestreduction of chlorophyll content in Chlorella vulgaris was found for 5-tert-butyl-N-(4-chloro-3-methylphenyl-pyrazine-2-carboxamide (3, IC50 = 44.0 μmol·L-1. The maximalflavonoid production (about 900% was reached after a twelve-hour elicitation processwith 6-chloropyrazine-2-carboxylic acid (3-iodo-4-methylphenyl-amide (2.

  20. Preharvest Application of Methyl Jasmonate as an Elicitor Improves the Yield and Phenolic Content of Artichoke.

    Science.gov (United States)

    Martínez-Esplá, Alejandra; Valero, Daniel; Martínez-Romero, Domingo; Castillo, Salvador; Giménez, María José; García-Pastor, Maria Emma; Serrano, María; Zapata, Pedro Javier

    2017-10-25

    The effects of methyl jasmonate (MeJa) treatment as an elicitor of artichoke plants [Cynara cardunculus var. scolymus (L.) Fiori] on the yield and quality attributes of artichokes, especially those related to individual phenolic content and antioxidant activity, at two harvest dates and along storage were analyzed in this research. Plants treated gave a higher yield of artichokes in comparison to control plants, with 0.55 kg more per plant. MeJa treatment also increased artichoke quality and phenolic content in the edible fraction at harvest and during storage at 2 °C for 28 days as a result of the accumulation of hydroxycinnamic acids and luteolin derivatives. In addition, antioxidant activity was enhanced by MeJa treatment and correlated with the total phenolic content. Results suggest that MeJa foliar application could be a simple and practical tool to improve the yield and phytochemical content on artichokes, with elicitation being a cheap and environmentally friendly procedure to improve the health-beneficial effects of artichoke consumption.

  1. Perception of Arabidopsis AtPep peptides, but not bacterial elicitors, accelerates starvation-induced senescence

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    Kay eGully

    2015-01-01

    Full Text Available Members of the AtPep group of Arabidopsis endogenous peptides have frequently been reported to induce pattern-triggered immunity and to increase resistance to diverse pathogens by amplifying the innate immune response. Here, we made the surprising observation that dark-induced leaf senescence was accelerated by the presence of Peps. Adult leaves as well as leaf discs of Col-0 wild type plants showed a Pep-triggered early onset of chlorophyll breakdown and leaf yellowing whereas pepr1 pepr2 double mutant plants were insensitive. In addition, this response was dependent on ethylene signaling and inhibited by the addition of cytokinins. Notably, addition of the bacterial elicitors flg22 or elf18, both potent inducers of pattern-triggered immunity, did not provoke an early onset of leaf senescence.Continuous darkness leads to energy deprivation and starvation and therewith promotes leaf senescence. We found that continuous darkness also strongly induced PROPEP3 transcription. Moreover, Pep-perception led to a rapid induction of PAO, APG7 and APG8a, genes indispensable for chlorophyll degradation as well as autophagy, respectively, and all three hallmarks of starvation and senescence. Notably, addition of sucrose as a source of energy inhibited the Pep-triggered early onset of senescence. In conclusion, we report that Pep-perception accelerates dark/starvation-induced senescence via an early induction of chlorophyll degradation and autophagy. This represents a novel and unique characteristic of PEPR signaling, unrelated to pattern-triggered immunity.

  2. Ureidopyrazine Derivatives: Synthesis and Biological Evaluation as Anti-Infectives and Abiotic Elicitors

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    Ghada Bouz

    2017-10-01

    Full Text Available Tuberculosis (TB caused by Mycobacterium tuberculosis (Mtb has become a frequently deadly infection due to increasing antimicrobial resistance. This serious issue has driven efforts worldwide to discover new drugs effective against Mtb. One research area is the synthesis and evaluation of pyrazinamide derivatives as potential anti-TB drugs. In this paper we report the synthesis and biological evaluations of a series of ureidopyrazines. Compounds were synthesized by reacting alkyl/aryl isocyanates with aminopyrazine or with propyl 5-aminopyrazine-2-carboxylate. Reactions were performed in pressurized vials using a CEM Discover microwave reactor with a focused field. Purity and chemical structures of products were assessed, and the final compounds were tested in vitro for their antimycobacterial, antibacterial, and antifungal activities. Propyl 5-(3-phenylureidopyrazine-2-carboxylate (compound 4, MICMtb = 1.56 μg/mL, 5.19 μM and propyl 5-(3-(4-methoxyphenylureidopyrazine-2-carboxylate (compound 6, MICMtb = 6.25 μg/mL, 18.91 μM had high antimycobacterial activity against Mtb H37Rv with no in vitro cytotoxicity on HepG2 cell line. Therefore 4 and 6 are suitable for further structural modifications that might improve their biological activity and physicochemical properties. Based on the structural similarity to 1-(2-chloropyridin-4-yl-3-phenylurea, a known plant growth regulator, two selected compounds were evaluated for similar activity as abiotic elicitors.

  3. Elicitor-induced transcription factors for metabolic reprogramming of secondary metabolism in Medicago truncatula

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    Dixon Richard A

    2008-12-01

    Full Text Available Abstract Background Exposure of Medicago truncatula cell suspension cultures to pathogen or wound signals leads to accumulation of various classes of flavonoid and/or triterpene defense molecules, orchestrated via a complex signalling network in which transcription factors (TFs are essential components. Results In this study, we analyzed TFs responding to yeast elicitor (YE or methyl jasmonate (MJ. From 502 differentially expressed TFs, WRKY and AP2/EREBP gene families were over-represented among YE-induced genes whereas Basic Helix-Loop-Helix (bHLH family members were more over-represented among the MJ-induced genes. Jasmonate ZIM-domain (JAZ transcriptional regulators were highly induced by MJ treatment. To investigate potential involvement of WRKY TFs in signalling, we expressed four Medicago WRKY genes in tobacco. Levels of soluble and wall bound phenolic compounds and lignin were increased in all cases. WRKY W109669 also induced tobacco endo-1,3-β-glucanase (NtPR2 and enhanced the systemic defense response to tobacco mosaic virus in transgenic tobacco plants. Conclusion These results confirm that Medicago WRKY TFs have broad roles in orchestrating metabolic responses to biotic stress, and that they also represent potentially valuable reagents for engineering metabolic changes that impact pathogen resistance.

  4. Partial purification of elicitors from Lentinula edodes basidiocarps protecting cucumber seedlings against Colletotrichum lagenarium

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    Di Piero Robson M.

    2006-01-01

    Full Text Available The shiitake mushroom (Lentinula edodes has been used in research involving the prevention and the control of human and plant diseases. In cucumber plants, treated with aqueous extracts from mushroom basidiocarps, there was a reduction in anthracnose severity caused by Colletotrichum lagenarium, and an increase in peroxidase activity in the leaves. With the aim of obtaining molecules of agronomic interest, the crude aqueous extract from L. edodes basidiocarp was fractioned with ammonium sulfate. The fraction corresponding to 40-80% of saturation (p40-80, the most effective in reducing anthracnose on cucumber cotyledons, was submitted to anion exchange chromatography (AEC. After AEC, six protein peaks were obtained and the peak V, containing 34% of the proteins present in p40-80, induced peroxidase increase in the cucumber cotyledons besides reducing anthracnose severity. Separation of peak V proteins by SDS-gel electrophoresis revealed the presence of more than one band in the gel. Thus, a partial purification of elicitors present in the L. edodes basidiocarp was achieved.

  5. Role of motility and chemotaxis in the pathogenesis of Dickeya dadantii 3937 (ex Erwinia chrysanthemi 3937).

    Science.gov (United States)

    Antúnez-Lamas, María; Cabrera-Ordóñez, Ezequiel; López-Solanilla, Emilia; Raposo, Rosa; Trelles-Salazar, Oswaldo; Rodríguez-Moreno, Andrés; Rodríguez-Palenzuela, Pablo

    2009-02-01

    Dickeya dadantii 3937 (ex Erwinia chrysanthemi), a member of the Enterobacteriaceae, causes soft rot in many economically important crops. A successful pathogen has to reach the interior of the plant in order to cause disease. To study the role of motility and chemotaxis in the pathogenicity of D. dadantii 3937, genes involved in the chemotactic signal transduction system (cheW, cheB, cheY and cheZ) and in the structure of the flagellar motor (motA) were mutagenized. All the mutant strains grew like the wild-type in culture media, and the production and secretion of pectolytic enzymes was not affected. As expected, the swimming ability of the mutant strains was reduced with respect to the wild-type: motA (94%), cheY (80%), cheW (74%), cheB (54%) and cheZ (48%). The virulence of the mutant strains was analysed in chicory, Saintpaulia and potato. The mutant strains were also tested for their capability to enter into Arabidopsis leaves. All the mutants showed a significant decrease of virulence in certain hosts; however, the degree of virulence reduction varied depending on the virulence assay. The ability to penetrate Arabidopsis leaves was impaired in all the mutants, whereas the capacity to colonize potato tubers after artificial inoculation was affected in only two mutant strains. In general, the virulence of the mutants could be ranked as motA

  6. Global effect of indole-3-acetic acid biosynthesis on multiple virulence factors of Erwinia chrysanthemi 3937.

    Science.gov (United States)

    Yang, Shihui; Zhang, Qiu; Guo, Jianhua; Charkowski, Amy O; Glick, Bernard R; Ibekwe, A Mark; Cooksey, Donald A; Yang, Ching-Hong

    2007-02-01

    Production of the plant hormone indole-3-acetic acid (IAA) is widespread among plant-associated microorganisms. The non-gall-forming phytopathogen Erwinia chrysanthemi 3937 (strain Ech3937) possesses iaaM (ASAP16562) and iaaH (ASAP16563) gene homologues. In this work, the null knockout iaaM mutant strain Ech138 was constructed. The IAA production by Ech138 was reduced in M9 minimal medium supplemented with l-tryptophan. Compared with wild-type Ech3937, Ech138 exhibited reduced ability to produce local maceration, but its multiplication in Saintpaulia ionantha was unaffected. The pectate lyase production of Ech138 was diminished. Compared with wild-type Ech3937, the expression levels of an oligogalacturonate lyase gene, ogl, and three endopectate lyase genes, pelD, pelI, and pelL, were reduced in Ech138 as determined by a green fluorescent protein-based fluorescence-activated cell sorting promoter activity assay. In addition, the transcription of type III secretion system (T3SS) genes, dspE (a putative T3SS effector) and hrpN (T3SS harpin), was found to be diminished in the iaaM mutant Ech138. Compared with Ech3937, reduced expression of hrpL (a T3SS alternative sigma factor) and gacA but increased expression of rsmA in Ech138 was also observed, suggesting that the regulation of T3SS and pectate lyase genes by IAA biosynthesis might be partially due to the posttranscriptional regulation of the Gac-Rsm regulatory pathway.

  7. Erwinia amylovora CRISPR elements provide new tools for evaluating strain diversity and for microbial source tracking.

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    Gayle C McGhee

    Full Text Available Clustered regularly interspaced short palindromic repeats (CRISPRs comprise a family of short DNA repeat sequences that are separated by non repetitive spacer sequences and, in combination with a suite of Cas proteins, are thought to function as an adaptive immune system against invading DNA. The number of CRISPR arrays in a bacterial chromosome is variable, and the content of each array can differ in both repeat number and in the presence or absence of specific spacers. We utilized a comparative sequence analysis of CRISPR arrays of the plant pathogen Erwinia amylovora to uncover previously unknown genetic diversity in this species. A total of 85 E. amylovora strains varying in geographic isolation (North America, Europe, New Zealand, and the Middle East, host range, plasmid content, and streptomycin sensitivity/resistance were evaluated for CRISPR array number and spacer variability. From these strains, 588 unique spacers were identified in the three CRISPR arrays present in E. amylovora, and these arrays could be categorized into 20, 17, and 2 patterns types, respectively. Analysis of the relatedness of spacer content differentiated most apple and pear strains isolated in the eastern U.S. from western U.S. strains. In addition, we identified North American strains that shared CRISPR genotypes with strains isolated on other continents. E. amylovora strains from Rubus and Indian hawthorn contained mostly unique spacers compared to apple and pear strains, while strains from loquat shared 79% of spacers with apple and pear strains. Approximately 23% of the spacers matched known sequences, with 16% targeting plasmids and 5% targeting bacteriophage. The plasmid pEU30, isolated in E. amylovora strains from the western U.S., was targeted by 55 spacers. Lastly, we used spacer patterns and content to determine that streptomycin-resistant strains of E. amylovora from Michigan were low in diversity and matched corresponding streptomycin-sensitive strains

  8. Effect of Different Elicitors and Preharvest Day Application on the Content of Phytochemicals and Antioxidant Activity of Butterhead Lettuce (Lactuca sativa var. capitata) Produced under Hydroponic Conditions.

    Science.gov (United States)

    Moreno-Escamilla, Jesús Omar; Alvarez-Parrilla, Emilio; de la Rosa, Laura A; Núñez-Gastélum, José Alberto; González-Aguilar, Gustavo A; Rodrigo-García, Joaquín

    2017-07-05

    The effect of four elicitors on phytochemical content in two varieties of lettuce was evaluated. The best preharvest day for application of each elicitor was chosen. Solutions of arachidonic acid (AA), salicylic acid (SA), methyl jasmonate (MJ), and Harpin protein (HP) were applied by foliar aspersion on lettuce leaves while cultivating under hydroponic conditions. Application of elicitors was done at 15, 7, 5, 3, or 1 day before harvest. Green lettuce showed the highest increase in phytochemical content when elicitors (AA, SA, and HP) were applied on day 7 before harvest. Similarly, antioxidant activity rose in all treatments on day 7. In red lettuce, the highest content of bioactive molecules occurred in samples treated on day 15. AA, SA, and HP were the elicitors with the highest effect on phytochemical content for both varieties, mainly on polyphenol content. Antioxidant activity also increased in response to elicitation. HPLC-MS showed an increase in the content of phenolic acids in green and red lettuce, especially after elicitation with SA, suggesting activation of the caffeic acid pathway due to elicitation.

  9. Horizontal Gene Acquisitions, Mobile Element Proliferation, and Genome Decay in the Host-Restricted Plant Pathogen Erwinia Tracheiphila.

    Science.gov (United States)

    Shapiro, Lori R; Scully, Erin D; Straub, Timothy J; Park, Jihye; Stephenson, Andrew G; Beattie, Gwyn A; Gleason, Mark L; Kolter, Roberto; Coelho, Miguel C; De Moraes, Consuelo M; Mescher, Mark C; Zhaxybayeva, Olga

    2016-03-18

    Modern industrial agriculture depends on high-density cultivation of genetically similar crop plants, creating favorable conditions for the emergence of novel pathogens with increased fitness in managed compared with ecologically intact settings. Here, we present the genome sequence of six strains of the cucurbit bacterial wilt pathogen Erwinia tracheiphila (Enterobacteriaceae) isolated from infected squash plants in New York, Pennsylvania, Kentucky, and Michigan. These genomes exhibit a high proportion of recent horizontal gene acquisitions, invasion and remarkable amplification of mobile genetic elements, and pseudogenization of approximately 20% of the coding sequences. These genome attributes indicate that E. tracheiphila recently emerged as a host-restricted pathogen. Furthermore, chromosomal rearrangements associated with phage and transposable element proliferation contribute to substantial differences in gene content and genetic architecture between the six E. tracheiphila strains and other Erwinia species. Together, these data lead us to hypothesize that E. tracheiphila has undergone recent evolution through both genome decay (pseudogenization) and genome expansion (horizontal gene transfer and mobile element amplification). Despite evidence of dramatic genomic changes, the six strains are genetically monomorphic, suggesting a recent population bottleneck and emergence into E. tracheiphila's current ecological niche. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  10. Erwinia amylovora Novel Plasmid pEI70: Complete Sequence, Biogeography, and Role in Aggressiveness in the Fire Blight Phytopathogen

    Science.gov (United States)

    Llop, Pablo; Cabrefiga, Jordi; Smits, Theo H. M.; Dreo, Tanja; Barbé, Silvia; Pulawska, Joanna; Bultreys, Alain; Blom, Jochen; Duffy, Brion; Montesinos, Emilio; López, María M.

    2011-01-01

    Comparative genomics of several strains of Erwinia amylovora, a plant pathogenic bacterium causal agent of fire blight disease, revealed that its diversity is primarily attributable to the flexible genome comprised of plasmids. We recently identified and sequenced in full a novel 65.8 kb plasmid, called pEI70. Annotation revealed a lack of known virulence-related genes, but found evidence for a unique integrative conjugative element related to that of other plant and human pathogens. Comparative analyses using BLASTN showed that pEI70 is almost entirely included in plasmid pEB102 from E. billingiae, an epiphytic Erwinia of pome fruits, with sequence identities superior to 98%. A duplex PCR assay was developed to survey the prevalence of plasmid pEI70 and also that of pEA29, which had previously been described in several E. amylovora strains. Plasmid pEI70 was found widely dispersed across Europe with frequencies of 5–92%, but it was absent in E. amylovora analyzed populations from outside of Europe. Restriction analysis and hybridization demonstrated that this plasmid was identical in at least 13 strains. Curing E. amylovora strains of pEI70 reduced their aggressiveness on pear, and introducing pEI70 into low-aggressiveness strains lacking this plasmid increased symptoms development in this host. Discovery of this novel plasmid offers new insights into the biogeography, evolution and virulence determinants in E. amylovora. PMID:22174857

  11. Production of isomaltulose obtained by Erwinia sp. cells submitted to different treatments and immobilized in calcium alginate

    Directory of Open Access Journals (Sweden)

    Haroldo Yukio Kawaguti

    2011-03-01

    Full Text Available In recent decades, there has been an increase in the studies of isomaltulose obtainment, due to its physicochemical properties and physiological health benefits. These properties, which include low cariogenicity, low glycemic index and greater stability, allow the use of this sweetener as a substitute for sucrose in foods; besides the fact that it can be converted to isomalt, a dietary non-cariogenic sugar alcohol used in pharmaceuticals as well as in the food industry. Isomaltulose (6-O-α-D-glucopyronosyl-1-6-D-fructofuranose is a disaccharide reducer obtained by the enzymatic conversion of sucrose - the α-glucosyltransferase enzyme. Different treatments were performed for the preparation of whole cells; lysed cells; and crude enzyme extract of Erwinia sp. D12 strain immobilized in calcium alginate. The packed bed column of granules, containing Erwinia sp. cells sonicated and immobilized in calcium alginate (CSI, reached a maximum conversion of 53-59% sucrose into isomaltulose and it presented activity for 480 hours. The converted syrup was purified and the isomaltulose crystallization was performed through the lowering of temperature. The isomaltulose crystals presented purity of 96.5%.

  12. Análise de crescimento de duas cultivares de cevada após tratamentos com elicitores e fungicidas Growth analysis of two barley cultivars after elicitors and fungicides treatment

    Directory of Open Access Journals (Sweden)

    Noemir Antoniazzi

    2006-08-01

    Full Text Available Para o controle da mancha marrom da cevada, causada pelo fungo Bipolaris sorokiniana, têm sido utilizados fungicidas e mais recentemente foi proposto o uso de elicitores. O objetivo deste trabalho foi avaliar o desenvolvimento de duas cultivares de cevada cervejeira, "BRS 195" e "BRS 225", em resposta à aplicação de elicitores goma xantana e alicina e do fungicida epoxiconazole + pyraclostrobin, comparativamente a plantas não tratadas. O experimento foi conduzido na Fundação Agrária de Pesquisa Agropecuária (FAPA, Guarapuava - PR, no delineamento de blocos completos casualizados. Na análise de crescimento, foram determinados o índice de área foliar (IAF, a taxa de crescimento relativo (TCR e a taxa assimilatória líquida (TAL. Observou-se desenvolvimento semelhante das cultivares em todos os tratamentos. A cultivar "BRS 225" registrou maior acúmulo de matéria seca no período de avaliação por apresentar um ciclo vegetativo mais curto. O IAF aumentou até a fase de emborrachamento das plantas, com posterior decréscimo. A TCR diminuiu da primeira para a última coleta. A TAL diminuiu até 57 dias após a emergência, seguindo aumento no decorrer das avaliações.In order to control barley boun spot, caused by Bipolaris sorokiniana, fungicides and more recently elicitors have been used. The objective of this work was to evaluate the development of two barley cultivars (BRS 195 and 225 in response to treatment with two elicitors xanthan gum and alicin and the fungicide epoxiconazole + pyraclostrobin compared with non treated control plants. The experiment was carried out at Fundação Agrária de Pesquisa Agropecuária (FAPA, Guarapuava - PR, in a randomized complete block design. In the growth analysis, they were performed calculating the leaf area index (LAI, relative growth rate (RGR and net assimilation rate (NAR. A similar development was observed for both cultivars in all treatments. The cultivar BRS 225 showed higher dry

  13. Comparative kinetics of fatty acid-amino acid conjugate elicitor biosynthesis by midgut tissue microsomes of Lepidopterous caterpillar larvae.

    Science.gov (United States)

    Lait, Cameron G; Lobaido, Melanie J; Wiester, Amy J; Kossak, Sarah; Tumlinson, James H

    2010-12-01

    N-Linolenoyl-L-glutamine is one of several structurally similar fatty acid-amino acid conjugate (FAC) elicitors found in the oral secretions of Lepidopterous caterpillars and its biosynthesis is catalyzed by membrane-associated alimentary tissue enzyme(s). FAC elicitors comprise 17-hydroxylated or non-hydroxylated linolenic acid coupled with L-glutamine or L-glutamate by an amide bond. We demonstrate in vitro biosynthesis of N-linolenoyl-L-glutamine by Manduca sexta, Heliothis virescens, and Helicoverpa zea tissue microsomes. Comparison of N-linolenoyl-L-glutamine biosynthesis kinetics for these species suggests that concurrent biosynthesis and hydrolysis contribute to proportions of FAC elicitors found in their oral secretions. The apparent K(m) values for coupling of sodium linolenate were 8.75±0.79, 14.3±3.7 and 20.7±3.4 mM and V(max) values were 2.92±0.14, 6.81±1.2 and 4.95±0.55 nmol/min/mg protein for H. zea, H. virescens and M. sexta, respectively. The K(m) values for coupling of L-glutamine were 10.5±0.26, 22.3±2.0 and 18.9±2.4 mM and V(max) values were 1.78±0.21, 3.71±0.50 and 2.49±0.41 nmol/min/mg of protein for H. zea, H. virescens and M. sexta, respectively. © 2010 Wiley Periodicals, Inc.

  14. Comparative Effectiveness of Potential Elicitors of Plant Resistance against Spodoptera frugiperda (J. E. Smith (Lepidoptera: Noctuidae in Four Crop Plants.

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    John W Gordy

    Full Text Available Feeding by insect herbivores activates plant signaling pathways, resulting in the enhanced production of secondary metabolites and other resistance-related traits by injured plants. These traits can reduce insect fitness, deter feeding, and attract beneficial insects. Organic and inorganic chemicals applied as a foliar spray, seed treatment, or soil drench can activate these plant responses. Azelaic acid (AA, benzothiadiazole (BTH, gibberellic acid (GA, harpin, and jasmonic acid (JA are thought to directly mediate plant responses to pathogens and herbivores or to mimic compounds that do. The effects of these potential elicitors on the induction of plant defenses were determined by measuring the weight gains of fall armyworm, Spodoptera frugiperda (J. E. Smith (FAW (Lepidoptera: Noctuidae larvae on four crop plants, cotton, corn, rice, and soybean, treated with the compounds under greenhouse conditions. Treatment with JA consistently reduced growth of FAW reared on treated cotton and soybean. In contrast, FAW fed BTH- and harpin-treated cotton and soybean tissue gained more weight than those fed control leaf tissue, consistent with negative crosstalk between the salicylic acid and JA signaling pathways. No induction or inconsistent induction of resistance was observed in corn and rice. Follow-up experiments showed that the co-application of adjuvants with JA failed to increase the effectiveness of induction by JA and that soybean looper [Chrysodeixis includens (Walker], a relative specialist on legumes, was less affected by JA-induced responses in soybean than was the polyphagous FAW. Overall, the results of these experiments demonstrate that the effectiveness of elicitors as a management tactic will depend strongly on the identities of the crop, the pest, and the elicitor involved.

  15. Comparative Effectiveness of Potential Elicitors of Plant Resistance against Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in Four Crop Plants.

    Science.gov (United States)

    Gordy, John W; Leonard, B Rogers; Blouin, David; Davis, Jeffrey A; Stout, Michael J

    2015-01-01

    Feeding by insect herbivores activates plant signaling pathways, resulting in the enhanced production of secondary metabolites and other resistance-related traits by injured plants. These traits can reduce insect fitness, deter feeding, and attract beneficial insects. Organic and inorganic chemicals applied as a foliar spray, seed treatment, or soil drench can activate these plant responses. Azelaic acid (AA), benzothiadiazole (BTH), gibberellic acid (GA), harpin, and jasmonic acid (JA) are thought to directly mediate plant responses to pathogens and herbivores or to mimic compounds that do. The effects of these potential elicitors on the induction of plant defenses were determined by measuring the weight gains of fall armyworm, Spodoptera frugiperda (J. E. Smith) (FAW) (Lepidoptera: Noctuidae) larvae on four crop plants, cotton, corn, rice, and soybean, treated with the compounds under greenhouse conditions. Treatment with JA consistently reduced growth of FAW reared on treated cotton and soybean. In contrast, FAW fed BTH- and harpin-treated cotton and soybean tissue gained more weight than those fed control leaf tissue, consistent with negative crosstalk between the salicylic acid and JA signaling pathways. No induction or inconsistent induction of resistance was observed in corn and rice. Follow-up experiments showed that the co-application of adjuvants with JA failed to increase the effectiveness of induction by JA and that soybean looper [Chrysodeixis includens (Walker)], a relative specialist on legumes, was less affected by JA-induced responses in soybean than was the polyphagous FAW. Overall, the results of these experiments demonstrate that the effectiveness of elicitors as a management tactic will depend strongly on the identities of the crop, the pest, and the elicitor involved.

  16. Evaluation of Likelihood of Co-Occurrence of Erwinia amylovora with Mature Fruit of Winter Pear.

    Science.gov (United States)

    Temple, Todd N; Stockwell, Virginia O; Pusey, P Lawrence; Johnson, Kenneth B

    2007-10-01

    ABSTRACT Phytosanitary concerns about fire blight prohibit export of U.S.-grown pears to some countries without this disease. To examine these concerns, we evaluated the potential for co-occurrence of Erwinia amylovora with mature, symptomless winter pear fruit by inoculation experiments and by survey of commercial orchards. Immature pear and apple fruit were inoculated in orchards with E. amylovora strain 153N as resuspended lyophilized cells or as ooze from diseased tissues. Regardless of inoculum source, population size of Ea153N on fruit declined by an order of magnitude every 3 to 4 days during the first 2 weeks after inoculation; at 56 days after inoculation, Ea153N was not detected, except on 1 of 450 fruit with 4 colony forming units (CFU). After inoculation of flowers, calyx-end survival of Ea153N on pear and apple fruit declined from high populations at petal fall to a few cells at harvest, with no detection of the pathogen after a 7-week cold storage. Migration of Ea153N into symptomless pear fruit from diseased branches was evaluated by enrichment assay and nested polymerase chain reaction of internal fruit core tissues; these assays failed to detect the pathogen in healthy fruit from diseased trees. At harvest, E. amylovora could not be detected on 5,599 of 5,600 fruit of d'Anjou pear sampled from commercial orchards in major production areas of the Pacific Northwest; one fruit yielded 32 CFU of the pathogen. Postharvest, mature pear fruit contaminated with Ea153N and subsequently wounded required a dose of >10,000 cells at the wound site to allow for persistence of the pathogen through a 7-week-cold storage. We conclude that epiphytic E. amylovora shows similar survival characteristics on both pear and apple fruit, this pathogen is not an endophyte within mature symptomless pear fruit, its presence is exceptionally rare on commercially produced fruit, and that epiphytic survival of E. amylovora through a postharvest chilling period is unlikely given

  17. Characterization of indigoidine biosynthetic genes in Erwinia chrysanthemi and role of this blue pigment in pathogenicity.

    Science.gov (United States)

    Reverchon, Sylvie; Rouanet, Carine; Expert, Dominique; Nasser, William

    2002-02-01

    In the plant-pathogenic bacterium Erwinia chrysanthemi production of pectate lyases, the main virulence determinant, is modulated by a complex network involving several regulatory proteins. One of these regulators, PecS, also controls the synthesis of a blue pigment identified as indigoidine. Since production of this pigment is cryptic in the wild-type strain, E. chrysanthemi ind mutants deficient in indigoidine synthesis were isolated by screening a library of Tn5-B21 insertions in a pecS mutant. These ind mutations were localized close to the regulatory pecS-pecM locus, immediately downstream of pecM. Sequence analysis of this DNA region revealed three open reading frames, indA, indB, and indC, involved in indigoidine biosynthesis. No specific function could be assigned to IndA. In contrast, IndB displays similarity to various phosphatases involved in antibiotic synthesis and IndC reveals significant homology with many nonribosomal peptide synthetases (NRPS). The IndC product contains an adenylation domain showing the signature sequence DAWCFGLI for glutamine recognition and an oxidation domain similar to that found in various thiazole-forming NRPS. These data suggest that glutamine is the precursor of indigoidine. We assume that indigoidine results from the condensation of two glutamine molecules that have been previously cyclized by intramolecular amide bond formation and then dehydrogenated. Expression of ind genes is strongly derepressed in the pecS background, indicating that PecS is the main regulator of this secondary metabolite synthesis. DNA band shift assays support a model whereby the PecS protein represses indA and indC expression by binding to indA and indC promoter regions. The regulatory link, via pecS, between indigoidine and virulence factor production led us to explore a potential role of indigoidine in E. chrysanthemi pathogenicity. Mutants impaired in indigoidine production were unable to cause systemic invasion of potted Saintpaulia ionantha

  18. Characterization of the pelL gene encoding a novel pectate lyase of Erwinia chrysanthemi 3937.

    Science.gov (United States)

    Lojkowska, E; Masclaux, C; Boccara, M; Robert-Baudouy, J; Hugouvieux-Cotte-Pattat, N

    1995-06-01

    Erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pelA, pelB, pelC, pelD and pelE genes. Recently, a new set of pectate lyases was identified in E. chrysanthemi mutants deleted of those pel genes. We cloned the pelL gene, encoding one of these secondary pectate lyases of E. chrysanthemi 3937, from a genomic bank of a strain deleted of the five major pel genes. The nucleotide sequence of the region containing the pelL gene was determined. The pelL reading frame is 1275 bases long, corresponding to a protein of 425 amino acids including a typical amino-terminal signal sequence of 25 amino acids. Comparison of the amino acid sequences of PelL and the exo-pectate lyase PelX of E. chrysanthemi EC16 revealed a low homology, limited to 220 residues of the central part of the proteins. No homology was detected with other bacterial pectinolytic enzymes. Regulation of pelL transcription was analysed using gene fusion. As shown for the other pel genes, the transcription of pelL is dependent on various environmental conditions. It is induced by pectic catabolic products and affected by growth phase, temperature, iron starvation, osmolarity, anaerobiosis, nitrogen starvation and catabolite repression. Regulation of pelL expression appeared to be independent of the KdgR repressor, which controls all the steps of pectin catabolism. In contrast, the pecS gene, which is involved in regulation of the synthesis of the major pectate lyases and of cellulase, also appeared to be involved in pelL expression. The PelL protein is able to macerate plant tissue. This enzyme has a basic isoelectric point, presents an endo-cleaving activity on polygalacturonate or partially methylated pectin, with a basic pH optimum and an absolute requirement for Ca2+. The pelL mutant displayed a reduced virulence on potato tubers and Saintpaulia ionantha plants, demonstrating the important role of this enzyme in soft-rot disease.

  19. Characterization of the exopolygalacturonate lyase PelX of Erwinia chrysanthemi 3937.

    Science.gov (United States)

    Shevchik, V E; Kester, H C; Benen, J A; Visser, J; Robert-Baudouy, J; Hugouvieux-Cotte-Pattat, N

    1999-03-01

    Erwinia chrysanthemi 3937 secretes several pectinolytic enzymes, among which eight isoenzymes of pectate lyases with an endo-cleaving mode (PelA, PelB, PelC, PelD, PelE, PelI, PelL, and PelZ) have been identified. Two exo-cleaving enzymes, the exopolygalacturonate lyase, PelX, and an exo-poly-alpha-D-galacturonosidase, PehX, have been previously identified in other E. chrysanthemi strains. Using a genomic bank of a 3937 mutant with the major pel genes deleted, we cloned a pectinase gene identified as pelX, encoding the exopolygalacturonate lyase. The deduced amino acid sequence of the 3937 PelX is very similar to the PelX of another E. chrysanthemi strain, EC16, except in the 43 C-terminal amino acids. PelX also has homology to the endo-pectate lyase PelL of E. chrysanthemi but has a N-terminal extension of 324 residues. The transcription of pelX, analyzed by gene fusions, is dependent on several environmental conditions. It is induced by pectic catabolic products and affected by growth phase, oxygen limitation, nitrogen starvation, and catabolite repression. Regulation of pelX expression is dependent on the KdgR repressor, which controls almost all the steps of pectin catabolism, and on the global activator of sugar catabolism, cyclic AMP receptor protein. In contrast, PecS and PecT, two repressors of the transcription of most pectate lyase genes, are not involved in pelX expression. The pelX mutant displayed reduced pathogenicity on chicory leaves, but its virulence on potato tubers or Saintpaulia ionantha plants did not appear to be affected. The purified PelX protein has no maceration activity on plant tissues. Tetragalacturonate is the best substrate of PelX, but PelX also has good activity on longer oligomers. Therefore, the estimated number of binding subsites for PelX is 4, extending from subsites -2 to +2. PelX and PehX were shown to be localized in the periplasm of E. chrysanthemi 3937. PelX catalyzed the formation of unsaturated digalacturonates by

  20. Nitric Oxide Synthase-Mediated Phytoalexin Accumulation in Soybean Cotyledons in Response to the Diaporthe phaseolorum f. sp. meridionalis Elicitor1

    Science.gov (United States)

    Modolo, Luzia Valentina; Cunha, Fernando Queiroz; Braga, Márcia Regina; Salgado, Ione

    2002-01-01

    Phytoalexin biosynthesis is part of the defense mechanism of soybean (Glycine max) plants against attack by the fungus Diaporthe phaseolorum f. sp. meridionalis (Dpm), the causal agent of stem canker disease. The treatment of soybean cotyledons with Dpm elicitor or with sodium nitroprusside (SNP), a nitric oxide (NO) donor, resulted in a high accumulation of phytoalexins. This response did not occur when SNP was replaced by ferricyanide, a structural analog of SNP devoid of the NO moiety. Phytoalexin accumulation induced by the fungal elicitor, but not by SNP, was prevented when cotyledons were pretreated with NO synthase (NOS) inhibitors. The Dpm elicitor also induced NOS activity in soybean tissues proximal to the site of inoculation. The induced NOS activity was Ca2+- and NADPH-dependent and was sensitive to the NOS inhibitors NG-nitro-l-arginine methyl ester, aminoguanidine, and l-N6-(iminoethyl) lysine. NOS activity was not observed in SNP-elicited tissues. An antibody to brain NOS labeled a 166-kD protein in elicited and nonelicited cotyledons. Isoflavones (daidzein and genistein), pterocarpans (glyceollins), and flavones (apigenin and luteolin) were identified after exposure to the elicitor or SNP, although the accumulation of glyceollins and apigenin was limited in SNP-elicited compared with fungal-elicited cotyledons. NOS activity preceded the accumulation of these flavonoids in tissues treated with the Dpm elicitor. The accumulation of these metabolites was faster in SNP-elicited than in fungal-elicited cotyledons. We conclude that the response of soybean cotyledons to Dpm elicitor involves NO formation via a constitutive NOS-like enzyme that triggers the biosynthesis of antimicrobial flavonoids. PMID:12427995

  1. Structural Characterization of Oligochitosan Elicitor from Fusarium sambucinum and Its Elicitation of Defensive Responses in Zanthoxylum bungeanum

    Directory of Open Access Journals (Sweden)

    Peiqin Li

    2016-12-01

    Full Text Available Oligosaccharide elicitors from pathogens have been shown to play major roles in host plant defense responses involving plant–pathogen chemoperception and interaction. In the present study, chitosan and oligochitosan were prepared from pathogen Fusarium sambucinum, and their effects on infection of Zanthoxylum bungeanum stems were investigated. Results showed that oligochitosan inhibited the infection of the pathogen, and that the oligochitosan fraction with a degree of polymerization (DP between 5 and 6 showed the optimal effect. Oligochitosan DP5 was purified from fraction DP5-6 and was structurally characterized using electrospray ionization mass spectrometry, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. Oligochitosan DP5 showed significant inhibition against the infection of the pathogenic fungi on host plant stems. An investigation of the mechanism underlying this effect showed that oligochitosan DP5 increased the activities of defensive enzymes and accumulation of phenolics in host Z. bungeanum. These results suggest that oligochitosan from pathogenic fungi can mediate the infection of host plants with a pathogen by acting as an elicitor that triggers the defense system of a plant. This information will be valuable for further exploration of the interactions between the pathogen F. sambucinum and host plant Z. bungeanum.

  2. Structural Characterization of Oligochitosan Elicitor from Fusarium sambucinum and Its Elicitation of Defensive Responses in Zanthoxylum bungeanum.

    Science.gov (United States)

    Li, Peiqin; Linhardt, Robert J; Cao, Zhimin

    2016-12-10

    Oligosaccharide elicitors from pathogens have been shown to play major roles in host plant defense responses involving plant-pathogen chemoperception and interaction. In the present study, chitosan and oligochitosan were prepared from pathogen Fusarium sambucinum , and their effects on infection of Zanthoxylum bungeanum stems were investigated. Results showed that oligochitosan inhibited the infection of the pathogen, and that the oligochitosan fraction with a degree of polymerization (DP) between 5 and 6 showed the optimal effect. Oligochitosan DP5 was purified from fraction DP5-6 and was structurally characterized using electrospray ionization mass spectrometry, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. Oligochitosan DP5 showed significant inhibition against the infection of the pathogenic fungi on host plant stems. An investigation of the mechanism underlying this effect showed that oligochitosan DP5 increased the activities of defensive enzymes and accumulation of phenolics in host Z. bungeanum . These results suggest that oligochitosan from pathogenic fungi can mediate the infection of host plants with a pathogen by acting as an elicitor that triggers the defense system of a plant. This information will be valuable for further exploration of the interactions between the pathogen F. sambucinum and host plant Z. bungeanum .

  3. Effects of Polysaccharide Elicitors on Secondary Metabolite Production and Antioxidant Response in Hypericum perforatum L. Shoot Cultures

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    Sonja Gadzovska Simic

    2014-01-01

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

  4. Fungal Elicitor MoHrip2 Induces Disease Resistance in Rice Leaves, Triggering Stress-Related Pathways.

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    Najeeb Ullah Khan

    Full Text Available MoHrip2 Magnaporthe oryzae hypersensitive protein 2 is an elicitor protein of rice blast fungus M. oryzae. Rice seedlings treated with MoHrip2 have shown an induced resistance to rice blast. To elucidate the mechanism underlying this MoHrip2 elicitation in rice, we used differential-display 2-D gel electrophoresis and qRT-PCR to assess the differential expression among the total proteins extracted from rice leaves at 24 h after treatment with MoHrip2 and buffer as a control. Among ~1000 protein spots detected on each gel, 10 proteins were newly induced, 4 were up-regulated, and 3 were down-regulated in MoHrip2-treated samples compared with the buffer control. Seventeen differentially expressed proteins were detected using MS/MS analysis and categorized into six groups according to their putative function: defense-related transcriptional factors, signal transduction-related proteins, reactive oxygen species (ROS production, programmed cell death (PCD, defense-related proteins, and photosynthesis and energy-related proteins. The qPCR results (relative expression level of genes further supported the differential expression of proteins in MoHrip2-treated rice leaves identified with 2D-gel, suggesting that MoHrip2 triggers an early defense response in rice leaves via stress-related pathways, and the results provide evidence for elicitor-induced resistance at the protein level.

  5. Elucidation of the role of oleosin in off-flavour generation in soymeal through supercritical CO₂ and biotic elicitor treatments.

    Science.gov (United States)

    Kumari, Sweta; Memba, Lucia Joseph; Dahuja, Anil; Vinutha, T; Saha, Supradip; Sachdev, Archana

    2016-08-15

    Defatting soybean by sophisticated oil extraction method utilising supercritical CO2 resulted in a significant decrease in the residual phospholipids (PLs) compared with soymeal obtained by conventional cold percolation method utilising hexane as the extraction solvent. Interestingly, the levels of residual PLs showed a proportionate relationship with thiobarbituric acid (TBA) number, an indicator of lipid peroxidation responsible for off-flavour generation. Furthermore, two oleosins (18 and 24 kDa) were isolated from the oil bodies extracted from soybean seeds and positively characterised for phospholipase A2 (PLA2) activity, suggesting their plausible involvement in off-flavour generation in soymeal. The treatment of soybean seeds, before oil extraction, with different concentrations of biotic elicitors such as chitosan and jasmonic acid also significantly reduced the levels of residual PLs as well as the TBA number. The biotic elicitor treatment could thus prove to be an important strategy for the reduction of off-flavour in protein-rich soymeal. Copyright © 2016. Published by Elsevier Ltd.

  6. Detecção de bacteriocinas produzidas por bactérias fitopatogênicas dos gêneros Erwinia, Pseudomonas e Xanthomonas Detection of bacteriocins produced by plant pathogenic bacteria from the genera Erwinia, Pseudomonas and Xanthomonas

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    C.M.R. de Biagi

    1992-01-01

    Full Text Available A detecção da produção de bacteriocinas foi estudada em diferentes condições, utilizando-se linhagens de bactérias fitopatogênicas dos gêneros Erwinia, Pseudomonas e Xanthomonas. Obtiveram-se, respectivamente, 58,06%, 71,31% e 40,00% de linhagens produtoras no meio 523, que foi o mais indicado para detecção dessa produção. Uma maior concentração de ágar adicionada ao meio (1,5% produziu melhores resultados mas, a quantidade de meio nas placas não influenciou a detecção de bacteriocinas. O maior tempo de incubação utilizado (72 h. facilitou detecção de halos de produção de bacteriocinas. Irradiação com luz ultra-violeta em baixas doses parece facilitar a liberação de bacteriocinas, mas isso varia com a linhagem empregada.Detection of bacteriocin production was studied under distinct conditions using strains of plant pathogenic bacteria from the genera Erwinia, Pseudomonas and Xanthomonas. 58.06%, 79.31% and 40.00% of producing strains were found respectivelly in the three groups of bacteria using the 523 medium which was the best for the detection of bacteriocin production. Increasing agar concentrations added to the medium up to 1,5% improved the detection. The amount of medium added to the Petri dishes did not affect bacteriocin production. The longest incubation time (72h. improved the detection of haloe production. Ultra-violet irradiation in low dosages seems to improve the visualization of haloe prodution but this is dependent on the tested strains.

  7. Genome comparison of the epiphytic bacteria Erwinia billingiae and E. tasmaniensis with the pear pathogen E. pyrifoliae

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    Kuhl Heiner

    2010-06-01

    Full Text Available Abstract Background The genus Erwinia includes plant-associated pathogenic and non-pathogenic Enterobacteria. Important pathogens such as Erwinia amylovora, the causative agent of fire blight and E. pyrifoliae causing bacterial shoot blight of pear in Asia belong to this genus. The species E. tasmaniensis and E. billingiae are epiphytic bacteria and may represent antagonists for biocontrol of fire blight. The presence of genes that are putatively involved in virulence in E. amylovora and E. pyrifoliae is of special interest for these species in consequence. Results Here we provide the complete genome sequences of the pathogenic E. pyrifoliae strain Ep1/96 with a size of 4.1 Mb and of the non-pathogenic species E. billingiae strain Eb661 with a size of 5.4 Mb, de novo determined by conventional Sanger sequencing and next generation sequencing techniques. Genome comparison reveals large inversions resulting from homologous recombination events. Furthermore, comparison of deduced proteins highlights a relation of E. billingiae strain Eb661 to E. tasmaniensis strain Et1/99 and a distance to E. pyrifoliae for the overall gene content as well as for the presence of encoded proteins representing virulence factors for the pathogenic species. Pathogenicity of E. pyrifoliae is supposed to have evolved by accumulation of potential virulence factors. E. pyrifoliae carries factors for type III secretion and cell invasion. Other genes described as virulence factors for E. amylovora are involved in the production of exopolysaccharides, the utilization of plant metabolites such as sorbitol and sucrose. Some virulence-associated genes of the pathogenic species are present in E. tasmaniensis but mostly absent in E. billingiae. Conclusion The data of the genome analyses correspond to the pathogenic lifestyle of E. pyrifoliae and underlines the epiphytic localization of E. tasmaniensis and E. billingiae as a saprophyte.

  8. Identification of a bacterial pectin acetyl esterase in Erwinia chrysanthemi 3937.

    Science.gov (United States)

    Shevchik, V E; Hugouvieux-Cotte-Pattat, N

    1997-06-01

    Erwinia chrysanthemi causes soft-rot diseases of various plants by enzymatic degradation of the pectin in plant cell walls. The structural complexity of pectin requires the combined action of several pectinases for its efficient breakdown. Three types of pectinases have so far been identified in E. chrysanthemi: two pectin methyl esterases (PemA, PemB), a polygalacturonase (PehX), and eight pectate lyases (PelA, PelB, PelC, PelD, PelE, PelL, PelZ, PelX). We report in this paper the analysis of a novel enzyme, the pectin acetyl esterase encoded by the paeY gene. No bacterial form of pectin acetyl esterases has been described previously, while plant tissues and some pectinolytic fungi were found to produce similar enzymes. The paeY gene is present in a cluster of five pectinase-encoding genes, pelA-pelE-pelD-paeY-pemA. The paeY open reading frame is 1650 bases long and encodes a 551-residue precursor protein of 60704Da, including a 25-amino-acid signal peptide. PaeY shares one region of homology with a rhamnogalacturonan acetyl esterase of Aspergillus aculeatus. To characterize the enzyme, the paeY gene was overexpressed and its protein product was purified. PaeY releases acetate from sugar-beet pectin and from various synthetic substrates. Moreover, the enzyme was shown to act in synergy with other pectinases. The de-esterification rate by PaeY increased after previous demethylation of the pectins by PemA and after depolymerization of the pectin by pectate lyases. In addition, the degradation of sugar-beet pectin by pectate lyases is favoured after the removal of methyl and acetyl groups by PemA and PaeY, respectively. The paeY gene was first identified on the basis of its regulation, which shares several characteristics with that of other pectinases. Analysis of the paeY transcription, using gene fusions, revealed that it is induced by pectic catabolic products and is affected by growth phase, oxygen limitation and catabolite repression. Regulation of pae

  9. Quantitative 1H NMR metabolomics reveals extensive metabolic reprogramming of primary and secondary metabolism in elicitor-treated opium poppy cell cultures

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    Vogel Hans J

    2008-01-01

    Full Text Available Abstract Background Opium poppy (Papaver somniferum produces a diverse array of bioactive benzylisoquinoline alkaloids and has emerged as a model system to study plant alkaloid metabolism. The plant is cultivated as the only commercial source of the narcotic analgesics morphine and codeine, but also produces many other alkaloids including the antimicrobial agent sanguinarine. Modulations in plant secondary metabolism as a result of environmental perturbations are often associated with the altered regulation of other metabolic pathways. As a key component of our functional genomics platform for opium poppy we have used proton nuclear magnetic resonance (1H NMR metabolomics to investigate the interplay between primary and secondary metabolism in cultured opium poppy cells treated with a fungal elicitor. Results Metabolite fingerprinting and compound-specific profiling showed the extensive reprogramming of primary metabolic pathways in association with the induction of alkaloid biosynthesis in response to elicitor treatment. Using Chenomx NMR Suite v. 4.6, a software package capable of identifying and quantifying individual compounds based on their respective signature spectra, the levels of 42 diverse metabolites were monitored over a 100-hour time course in control and elicitor-treated opium poppy cell cultures. Overall, detectable and dynamic changes in the metabolome of elicitor-treated cells, especially in cellular pools of carbohydrates, organic acids and non-protein amino acids were detected within 5 hours after elicitor treatment. The metabolome of control cultures also showed substantial modulations 80 hours after the start of the time course, particularly in the levels of amino acids and phospholipid pathway intermediates. Specific flux modulations were detected throughout primary metabolism, including glycolysis, the tricarboxylic acid cycle, nitrogen assimilation, phospholipid/fatty acid synthesis and the shikimate pathway, all of which

  10. Rapid modification of the insect elicitor N-linolenoyl-glutamate via a lipoxygenase-mediated mechanism on Nicotiana attenuata leaves

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    VanDoorn Arjen

    2010-08-01

    Full Text Available Abstract Background Some plants distinguish mechanical wounding from herbivore attack by recognizing specific constituents of larval oral secretions (OS which are introduced into plant wounds during feeding. Fatty acid-amino acid conjugates (FACs are major constituents of Manduca sexta OS and strong elicitors of herbivore-induced defense responses in Nicotiana attenuata plants. Results The metabolism of one of the major FACs in M. sexta OS, N-linolenoyl-glutamic acid (18:3-Glu, was analyzed on N. attenuata wounded leaf surfaces. Between 50 to 70% of the 18:3-Glu in the OS or of synthetic 18:3-Glu were metabolized within 30 seconds of application to leaf wounds. This heat-labile process did not result in free α-linolenic acid (18:3 and glutamate but in the biogenesis of metabolites both more and less polar than 18:3-Glu. Identification of the major modified forms of this FAC showed that they corresponded to 13-hydroxy-18:3-Glu, 13-hydroperoxy-18:3-Glu and 13-oxo-13:2-Glu. The formation of these metabolites occurred on the wounded leaf surface and it was dependent on lipoxygenase (LOX activity; plants silenced in the expression of NaLOX2 and NaLOX3 genes showed more than 50% reduced rates of 18:3-Glu conversion and accumulated smaller amounts of the oxygenated derivatives compared to wild-type plants. Similar to 18:3-Glu, 13-oxo-13:2-Glu activated the enhanced accumulation of jasmonic acid (JA in N. attenuata leaves whereas 13-hydroxy-18:3-Glu did not. Moreover, compared to 18:3-Glu elicitation, 13-oxo-13:2-Glu induced the differential emission of two monoterpene volatiles (β-pinene and an unidentified monoterpene in irlox2 plants. Conclusions The metabolism of one of the major elicitors of herbivore-specific responses in N. attenuata plants, 18:3-Glu, results in the formation of oxidized forms of this FAC by a LOX-dependent mechanism. One of these derivatives, 13-oxo-13:2-Glu, is an active elicitor of JA biosynthesis and differential

  11. Inducible De Novo Biosynthesis of Isoflavonoids in Soybean Leaves by Spodoptera litura Derived Elicitors: Tracer Techniques Aided by High Resolution LCMS.

    Science.gov (United States)

    Nakata, Ryu; Kimura, Yuki; Aoki, Kenta; Yoshinaga, Naoko; Teraishi, Masayoshi; Okumoto, Yutaka; Huffaker, Alisa; Schmelz, Eric A; Mori, Naoki

    2016-12-01

    Isoflavonoids are a characteristic family of natural products in legumes known to mediate a range of plant-biotic interactions. For example, in soybean (Glycine max: Fabaceae) multiple isoflavones are induced and accumulate in leaves following attack by Spodoptera litura (Lepidoptera: Noctuidae) larvae. To quantitatively examine patterns of activated de novo biosynthesis, soybean (Var. Enrei) leaves were treated with a combination of plant defense elicitors present in S. litura gut content extracts and L-α-[(13)C9, (15)N]phenylalanine as a traceable isoflavonoid precursor. Combined treatments promoted significant increases in (13)C-labeled isoflavone aglycones (daidzein, formononetin, and genistein), (13)C-labeled isoflavone 7-O-glucosides (daidzin, ononin, and genistin), and (13)C-labeled isoflavone 7-O-(6″-O-malonyl-β-glucosides) (malonyldaidzin, malonylononin, and malonylgenistin). In contrast levels of (13)C-labeled flavones and flavonol (4',7-dihydroxyflavone, kaempferol, and apigenin) were not significantly altered. Curiously, application of fatty acid-amino acid conjugate (FAC) elicitors present in S. litura gut contents, namely N-linolenoyl-L-glutamine and N-linoleoyl-L-glutamine, both promoted the induced accumulation of isoflavone 7-O-glucosides and isoflavone 7-O-(6″-O-malonyl-β-glucosides), but not isoflavone aglycones in the leaves. These results demonstrate that at least two separate reactions are involved in elicitor-induced soybean leaf responses to the S. litura gut contents: one is the de novo biosynthesis of isoflavone conjugates induced by FACs, and the other is the hydrolysis of the isoflavone conjugates to yield isoflavone aglycones. Gut content extracts alone displayed no hydrolytic activity. The quantitative analysis of isoflavone de novo biosynthesis, with respect to both aglycones and conjugates, affords a useful bioassay system for the discovery of additional plant defense elicitor(s) in S. litura gut contents that specifically

  12. In-vitro antibacterial activities of the essential oils of aromatic plants against Erwinia herbicola (Lohnis) and pseudomonas putida (Kris Hamilton)

    OpenAIRE

    Pandey Abhay K.; Singh Pooja; Palni Uma T.; Tripathi N.N.

    2012-01-01

    This study was designed to examine in vitro antibacterial activities of essential oils extracted from 53 aromatic plants of Gorakhpur Division (UP, INDIA) for the control of two phytopathogenic bacteria namely Erwinia herbicola and Pseudomonas putida causing several post-harvest diseases in fruits and vegetables. Out of 53 oils screened, 8 oils such as Chenopodium ambrosioides, Citrus aurantium, Clausena pentaphylla, Hyptis suaveolens, Lippia alba, Mentha arvensis, Ocimum sanctum and Vi...

  13. Enhanced germination of barley (Hordeum vulgare L.) using chitooligosaccharide as an elicitor in seed priming to improve malt quality.

    Science.gov (United States)

    Lan, Weiqiu; Wang, Wei; Yu, Zhimin; Qin, Yanxia; Luan, Jing; Li, Xianzhen

    2016-11-01

    To study enhanced barley germination by chitooligosaccharide as an elicitor for improving the quality of malt. Barley germination for both radical and leaf sprouts was enhanced when chitooligosaccharide was added to the steeping water in the first steeping cycle. The activities of hydrolases (α-/β-amylase, proteinase and β-glucanase) and antioxidases (superoxide dismutase and catalase) in the resultant malt were increased in a dose-dependent manner when chitooligosaccharide was supplemented in the steeping water. Maximal promotion was at 1 mg chitooligosaccharide/l for α-/β-amylase and proteinase, and at 10 mg/l for β-glucanase, superoxide dismutase and catalase. Malt quality, including free α-amino nitrogen content, Kolbach index, malt extract content, diastatic power, wort viscosity and the ratio of glucose, maltose and maltotriose, was significantly improved by chitooligosaccharide in seed priming at 1 mg/l. Application of chitooligosaccharide in the steeping water promotes barley germination and improves the quality of malt.

  14. Impact of Exogenous Elicitors on Artemisinin Production and Trichome Density in Artemisia annua L. under Subtropical Conditions

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    Alka Jagdish DANGASH

    2014-09-01

    Full Text Available Artemisinin is a sesquiterpene lactone found in Artemisia annua having many medicinal properties. Therefore the factors affecting trichome initiation are important. In the present study, several strategies have been adapted to increase artemisinin production by treating them with nutrients, hormones and elicitors. Abscisic acid, Gibberellic acid (GA3, a combination of GA3+IAA (Gibberellic acid+indole acetic acid, Chitosan, Methyl jasmonate, Acetyl salicylic acid, Lead acetate, sodium chloride, and Nanozime were sprayed on plant at regular intervals. The glandular trichomes of leaves from Artemisia annua (Asteraceae were examined by light and scanning electron microscopy and the percentage artemisnin content was analyzed by HPTLC. Maximum artemisinin content % and trichome index (0.128 was found when methy jasmonate was applied and minimum artemisinin content % and trichome index was reported in NaCl & acetyl salicylic acid.

  15. Immobilization of Erwinia sp. D12 Cells in Alginate-Gelatin Matrix and Conversion of Sucrose into Isomaltulose Using Response Surface Methodology

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    Haroldo Yukio Kawaguti

    2011-01-01

    Full Text Available Isomaltulose is a noncariogenic reducing disaccharide and also a structural isomer of sucrose and is used by the food industry as a sucrose replacement. It is obtained through enzymatic conversion of microbial sucrose isomerase. An Erwinia sp. D12 strain is capable of converting sucrose into isomaltulose. The experimental design technique was used to study the influence of immobilization parameters on converting sucrose into isomaltulose in a batch process using shaken Erlenmeyer flasks. We assessed the effect of gelatin and transglutaminase addition on increasing the reticulation of granules of Erwinia sp. D12 cells immobilized in alginate. Independent parameters, sodium alginate concentration, cell mass concentration, CaCl2 concentration, gelatin concentration, and transglutaminase concentration had all a significant effect (P<0.05 on isomaltulose production. Erwinia sp. D12 cells immobilized in 3.0% (w/v sodium alginate, 47.0% (w/v cell mass, 0.3 molL-1 CaCl2, 1.7% (w/v gelatin and 0.15% (w/v transglutaminase presented sucrose conversion into isomaltulose, of around 50–60% in seven consecutive batches.

  16. Purification and characterization of a novel hypersensitive response-inducing elicitor from Magnaporthe oryzae that triggers defense response in rice.

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    Mingjia Chen

    Full Text Available BACKGROUND: Magnaporthe oryzae, the rice blast fungus, might secrete certain proteins related to plant-fungal pathogen interactions. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we report the purification, characterization, and gene cloning of a novel hypersensitive response-inducing protein elicitor (MoHrip1 secreted by M. oryzae. The protein fraction was purified and identified by de novo sequencing, and the sequence matched the genomic sequence of a putative protein from M. oryzae strain 70-15 (GenBank accession No. XP_366602.1. The elicitor-encoding gene mohrip1 was isolated; it consisted of a 429 bp cDNA, which encodes a polypeptide of 142 amino acids with a molecular weight of 14.322 kDa and a pI of 4.53. The deduced protein, MoHrip1, was expressed in E. coli. And the expression protein collected from bacterium also forms necrotic lesions in tobacco. MoHrip1 could induce the early events of the defense response, including hydrogen peroxide production, callose deposition, and alkalization of the extracellular medium, in tobacco. Moreover, MoHrip1-treated rice seedlings possessed significantly enhanced systemic resistance to M. oryzae compared to the control seedlings. The real-time PCR results indicated that the expression of some pathogenesis-related genes and genes involved in signal transduction could also be induced by MoHrip1. CONCLUSION/SIGNIFICANCE: The results demonstrate that MoHrip1 triggers defense responses in rice and could be used for controlling rice blast disease.

  17. A complex protein derivative acts as biogenic elicitor of grapevine resistance against powdery mildew under field conditions.

    Science.gov (United States)

    Nesler, Andrea; Perazzolli, Michele; Puopolo, Gerardo; Giovannini, Oscar; Elad, Yigal; Pertot, Ilaria

    2015-01-01

    Powdery mildew caused by Erysiphe necator is one of the most important grapevine diseases in several viticulture areas, and high fungicide input is required to control it. However, numerous synthetic chemical pesticides are under scrutiny due to concerns about their impact on human health and the environment. Biopesticides, such as biogenic elicitors, are a promising alternative to chemical fungicides. Although several studies have reported on effective elicitors against grapevine diseases, their efficacy under field conditions has not been investigated extensively or has occurred at rather limited levels. Our goal was to examine the efficacy of a protein-based composition, namely nutrient broth (NB), against powdery mildew under field conditions and to characterize its mechanism of action. Weekly treatments with NB was highly effective in controlling powdery mildew on grapevine across seasons with different disease pressures. The level of disease control achieved with NB was comparable to standard fungicide treatments both on leaves and bunches across three different years. NB has no direct toxic effect on the germination of E. necator conidia, and it activates plant resistance with both systemic and translaminar effect in experiments with artificial inoculation under controlled conditions. NB induced the expression of defense-related genes in grapevine, demonstrating stimulation of plant defense mechanisms, prior to and in the early stages of pathogen infection. NB is a natural derivative from meat and yeast, substances that tend not to raise concerns about toxicological and ecotoxicological properties. NB represents a valid control tool for integrated plant protection programs against powdery mildew, to reduce the use of synthetic pesticides on grapevine.

  18. "Fungal elicitors combined with a sucrose feed significantly enhance triterpene production of a Salvia fruticosa cell suspension".

    Science.gov (United States)

    Kümmritz, Sibylle; Louis, Marilena; Haas, Christiane; Oehmichen, Franz; Gantz, Stephanie; Delenk, Hubertus; Steudler, Susanne; Bley, Thomas; Steingroewer, Juliane

    2016-08-01

    Oleanolic (OA) and ursolic acid (UA) are plant secondary metabolites with diverse pharmacological properties. To reach reasonable productivities with plant cell suspension cultures, elicitation is a widely used strategy. Within the presented work, the effects of different elicitors on growth and production of OA and UA in a Salvia fruticosa cell suspension culture were examined. Beside commonly used elicitors like jasmonic acid (JA) and yeast extract, the influence of medium filtrates of the endophytic fungi Aspergillus niger and Trichoderma virens was investigated. The best eliciting effects were achieved with JA and fungal medium filtrates. Both increased the triterpene content by approximately 70 %. Since JA showed significant growth inhibition, the volumetric triterpene yield did not increase. But, adding fungal filtrates increased the volumetric triterpene yield by approximately 70 % to 32.6 mgOA l(-1) and 65.9 mgUA l(-1) for T. virens compared to the control with 19.4 mgOA l(-1) and 33.3 mgUA l(-1). An elicitation strategy combining fungal medium filtrate of T. virens with sucrose feeding significantly enhanced cell dry weight concentration to 22.2 g l(-1) as well as triterpene content by approximately 140 %. In total, this led to an approximately 500 % increase of volumetric triterpene yield referring to the control with final values of 112.9 mgOA l(-1) and 210.4 mgUA l(-1). Despite the doubled cultivation duration, productivities of 6.7 mgOA l(-1) day(-1) and 12.4 mgUA l(-1) day(-1) were reached. These results demonstrate methods by which increased productivities of triterpenes can be achieved to attain yields competing with intact plants.

  19. Expression of the dspA/E gene of Erwinia amylovora in non-host plant Arabidopsis thaliana

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    Hasan Murat Aksoy

    2017-01-01

    Full Text Available In the Erwinia amylovora genome, the hrp gene cluster containing the dspA/E/EB/F operon plays a crucial role in mediating the pathogenicity and the hypersensitive response (HR in the host plant. The role of the dspA/E gene derived from E. amylovora was investigated by monitoring the expression of the β-glucuronidase (GUS reporter system in transgenic Arabidopsis thaliana cv. Pri-Gus seedlings. A mutant ΔdspA/E strain of E. amylovora was generated to contain a deletion of the dspA/E gene for the purpose of this study. Two-week-old seedlings of GUS transgenic Arabidopsis were vacuum-infiltrated with the wild-type and the mutant (ΔdspA/E E. amylovora strains. The Arabidopsis seedlings were fixed and stained for GUS activity after 3–5 days following infiltration. The appearance of dense spots with blue staining on the Arabidopsis leaves indicated the typical characteristic of GUS activity. This observation indicated that the wild-type E. amylovora strain had induced a successful and efficient infection on the A. thaliana Pri-Gus leaves. In contrast, there was no visible GUS expression on leaf tissues which were inoculated with the ΔdspA/E mutant E. amylovora strain. These results indicate that the dspA/E gene is required by the bacterial cells to induce HR in non-host plants.

  20. Fire blight disease reactome: RNA-seq transcriptional profile of apple host plant defense responses to Erwinia amylovora pathogen infection.

    Science.gov (United States)

    Kamber, Tim; Buchmann, Jan P; Pothier, Joël F; Smits, Theo H M; Wicker, Thomas; Duffy, Brion

    2016-02-17

    The molecular basis of resistance and susceptibility of host plants to fire blight, a major disease threat to pome fruit production globally, is largely unknown. RNA-sequencing data from challenged and mock-inoculated flowers were analyzed to assess the susceptible response of apple to the fire blight pathogen Erwinia amylovora. In presence of the pathogen 1,080 transcripts were differentially expressed at 48 h post inoculation. These included putative disease resistance, stress, pathogen related, general metabolic, and phytohormone related genes. Reads, mapped to regions on the apple genome where no genes were assigned, were used to identify potential novel genes and open reading frames. To identify transcripts specifically expressed in response to E. amylovora, RT-PCRs were conducted and compared to the expression patterns of the fire blight biocontrol agent Pantoea vagans strain C9-1, another apple pathogen Pseudomonas syringae pv. papulans, and mock inoculated apple flowers. This led to the identification of a peroxidase superfamily gene that was lower expressed in response to E. amylovora suggesting a potential role in the susceptibility response. Overall, this study provides the first transcriptional profile by RNA-seq of the host plant during fire blight disease and insights into the response of susceptible apple plants to E. amylovora.

  1. Comparative genomics of 12 strains of Erwinia amylovora identifies a pan-genome with a large conserved core.

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    Rachel A Mann

    Full Text Available The plant pathogen Erwinia amylovora can be divided into two host-specific groupings; strains infecting a broad range of hosts within the Rosaceae subfamily Spiraeoideae (e.g., Malus, Pyrus, Crataegus, Sorbus and strains infecting Rubus (raspberries and blackberries. Comparative genomic analysis of 12 strains representing distinct populations (e.g., geographic, temporal, host origin of E. amylovora was used to describe the pan-genome of this major pathogen. The pan-genome contains 5751 coding sequences and is highly conserved relative to other phytopathogenic bacteria comprising on average 89% conserved, core genes. The chromosomes of Spiraeoideae-infecting strains were highly homogeneous, while greater genetic diversity was observed between Spiraeoideae- and Rubus-infecting strains (and among individual Rubus-infecting strains, the majority of which was attributed to variable genomic islands. Based on genomic distance scores and phylogenetic analysis, the Rubus-infecting strain ATCC BAA-2158 was genetically more closely related to the Spiraeoideae-infecting strains of E. amylovora than it was to the other Rubus-infecting strains. Analysis of the accessory genomes of Spiraeoideae- and Rubus-infecting strains has identified putative host-specific determinants including variation in the effector protein HopX1(Ea and a putative secondary metabolite pathway only present in Rubus-infecting strains.

  2. Carboxymethyl-cellulase from Erwinia chrysanthemi. II. Purification and partial characterization of an endo-. beta. -1,4-glucanase

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, M.H.; Chambost, J.P.; Magnan, M.; Cattaneo, J.

    1984-01-01

    The extracellular carboxymethyl-cellulase of Erwinia chrysanthemi, strain 3665, had a marked tendency to form aggregates when concentration and/or storage time of culture supernatant were increased. In submitting an unconcentrated glycerol culture supernatant to ion exchange chromatography, one major endo-..beta..-1,4,-glucanase could be isolated with a high degree of purity and partially characterized. The molecular size was 45 kd. The pI was 4.3. The enzyme rapidly decreased the viscosity of carboxymethyl-cellulose with a slow increase in the reducing sugars produced. It displayed its highest activity towards carboxymethyl-cellulose at a pH between 6.2 and 7.5. It had a significant capacity to hydrolyze amorphous cellulose such as phosphoric acid-swollen cellulose. The major products of this degradation were cellobiose and cellotriose. It exhibited a very low activity on microcrystalline cellulose. Glucose and cellobiose did not affect significantly its activity against carboxymethyl-cellulose. 21 references.

  3. Analysis of the LacI family regulators of Erwinia chrysanthemi 3937, involvement in the bacterial phytopathogenicity.

    Science.gov (United States)

    Van Gijsegem, Frédérique; Wlodarczyk, Aleksandra; Cornu, Amandine; Reverchon, Sylvie; Hugouvieux-Cotte-Pattat, Nicole

    2008-11-01

    Analysis of the regulators of the LacI family was performed in order to identify those potentially involved in pathogenicity of Erwinia chrysanthemi (Dickeya dadantii). Among the 18 members of the LacI family, the function of 11 members is either known or predicted and only 7 members have, as yet, no proposed function. Inactivation of these seven genes, called lfaR, lfbR, lfcR, lfdR, lfeR, lffR, and lfgR, demonstrated that four of them are important for plant infection. The lfaR and lfcR mutants showed a reduced virulence on chicory, Saintpaulia sp., and Arabidopsis. The lfeR mutant showed a reduced virulence on Arabidopsis. The lfdR mutant was more efficient than the wild-type strain in initiating maceration on Saintpaulia sp. The genetic environment of each regulator was examined to detect adjacent genes potentially involved in a common function. Construction of transcriptional fusions in these neighboring genes demonstrated that five regulators, LfaR, LfcR, LfeR, LffR, and LfgR, act as repressors of adjacent genes. Analysis of these fusions also indicated that the genes controlled by LfaR, LfcR, LfgR, and LffR are expressed during plant infection. Moreover, addition of crude plant extracts to culture medium demonstrated that the expression of the LfaR- and LfgR-controlled genes is specifically induced by plant components.

  4. Biological relevance of volatile organic compounds emitted during the pathogenic interactions between apple plants and Erwinia amylovora.

    Science.gov (United States)

    Cellini, Antonio; Buriani, Giampaolo; Rocchi, Lorenzo; Rondelli, Elena; Savioli, Stefano; Rodriguez Estrada, Maria T; Cristescu, Simona M; Costa, Guglielmo; Spinelli, Francesco

    2016-11-15

    Volatile organic compounds emitted during the infection of apple (Malus pumila var. domestica) plants by Erwinia amylovora or Pseudomonas syringae pv. syringae were studied by gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry, and used to treat uninfected plants. Infected plants showed a disease-specific emission of volatile organic compounds, including several bio-active compounds, such as hexenal isomers and 2,3-butanediol. Leaf growth promotion and a higher resistance to the pathogen, expressed as a lower bacterial growth and migration in plant tissues, were detected in plants exposed to volatile compounds from E. amylovora-infected plants. Transcriptional analysis revealed the activation of salicylic acid synthesis and signal transduction in healthy plants exposed to volatiles produced by E. amylovora-infected neighbour plants. In contrast, in the same plants, salicylic acid-dependent responses were repressed after infection, whereas oxylipin metabolism was activated. These results clarify some metabolic and ecological aspects of the pathogenic adaptation of E. amylovora to its host. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  5. Transcriptomic responses of the olive fruit fly Bactrocera oleae and its symbiont Candidatus Erwinia dacicola to olive feeding

    Science.gov (United States)

    Pavlidi, Nena; Gioti, Anastasia; Wybouw, Nicky; Dermauw, Wannes; Ben-Yosef, Michael; Yuval, Boaz; Jurkevich, Edouard; Kampouraki, Anastasia; van Leeuwen, Thomas; Vontas, John

    2017-02-01

    The olive fruit fly, Bactrocera oleae, is the most destructive pest of olive orchards worldwide. The monophagous larva has the unique capability of feeding on olive mesocarp, coping with high levels of phenolic compounds and utilizing non-hydrolyzed proteins present, particularly in the unripe, green olives. On the molecular level, the interaction between B. oleae and olives has not been investigated as yet. Nevertheless, it has been associated with the gut obligate symbiotic bacterium Candidatus Erwinia dacicola. Here, we used a B.oleae microarray to analyze the gene expression of larvae during their development in artificial diet, unripe (green) and ripe (black) olives. The expression profiles of Ca. E. dacicola were analyzed in parallel, using the Illumina platform. Several genes were found overexpressed in the olive fly larvae when feeding in green olives. Among these, a number of genes encoding detoxification and digestive enzymes, indicating a potential association with the ability of B. oleae to cope with green olives. In addition, a number of biological processes seem to be activated in Ca. E. dacicola during the development of larvae in olives, with the most notable being the activation of amino-acid metabolism.

  6. Diversity, evolution, and functionality of clustered regularly interspaced short palindromic repeat (CRISPR) regions in the fire blight pathogen Erwinia amylovora.

    Science.gov (United States)

    Rezzonico, Fabio; Smits, Theo H M; Duffy, Brion

    2011-06-01

    The clustered regularly interspaced short palindromic repeat (CRISPR)/Cas system confers acquired heritable immunity against mobile nucleic acid elements in prokaryotes, limiting phage infection and horizontal gene transfer of plasmids. In CRISPR arrays, characteristic repeats are interspersed with similarly sized nonrepetitive spacers derived from transmissible genetic elements and acquired when the cell is challenged with foreign DNA. New spacers are added sequentially and the number and type of CRISPR units can differ among strains, providing a record of phage/plasmid exposure within a species and giving a valuable typing tool. The aim of this work was to investigate CRISPR diversity in the highly homogeneous species Erwinia amylovora, the causal agent of fire blight. A total of 18 CRISPR genotypes were defined within a collection of 37 cosmopolitan strains. Strains from Spiraeoideae plants clustered in three major groups: groups II and III were composed exclusively of bacteria originating from the United States, whereas group I generally contained strains of more recent dissemination obtained in Europe, New Zealand, and the Middle East. Strains from Rosoideae and Indian hawthorn (Rhaphiolepis indica) clustered separately and displayed a higher intrinsic diversity than that of isolates from Spiraeoideae plants. Reciprocal exclusion was generally observed between plasmid content and cognate spacer sequences, supporting the role of the CRISPR/Cas system in protecting against foreign DNA elements. However, in several group III strains, retention of plasmid pEU30 is inconsistent with a functional CRISPR/Cas system.

  7. Suramin inhibits initiation of defense signaling by systemin, chitosan, and a β-glucan elicitor in suspension-cultured Lycopersicon peruvianum cells

    Science.gov (United States)

    Stratmann, Johannes; Scheer, Justin; Ryan, Clarence A.

    2000-01-01

    Systemin-mediated defense signaling in tomato (Lycopersicon esculentum) plants is analogous to the cytokine-mediated inflammatory response in animals. Herein, we report that the initiation of defense signaling in suspension-cultured cells of Lycopersicon peruvianum by the peptide systemin, as well as by chitosan and β-glucan elicitor from Phytophtora megasperma, is inhibited by the polysulfonated naphtylurea compound suramin, a known inhibitor of cytokine and growth factor receptor interactions in animal cells. Using a radioreceptor assay, we show that suramin interfered with the binding of the systemin analog 125I-Tyr-2,Ala-15-systemin to the systemin receptor with an IC50 of 160 μM. Additionally, labeling of the systemin receptor with a photoaffinity analog of systemin was inhibited in the presence of suramin. Receptor-mediated tyrosine phosphorylation of a 48-kDa mitogen-activated protein kinase and alkalinization of the medium of suspension-cultured cells in response to systemin and carbohydrate elicitors were also inhibited by suramin. The inhibition of medium alkalinization by suramin was reversible in the presence of high concentrations of systemin and carbohydrate elicitors. Calyculin A and erythrosin B, intracellular inhibitors of phosphatases and plasma membrane proton ATPases, respectively, both induce medium alkalinization, but neither response was inhibited by suramin. The polysulfonated compound heparin did not inhibit systemin-induced medium alkalinization. NF 007, a suramin derivative, induced medium alkalinization, indicating that neither NF 007 nor heparin interact with elicitor receptors like suramin. The data indicate that cell-surface receptors in plants show some common structural features with animal cytokine and growth factor receptors that can interact with suramin to interfere with ligand binding. PMID:10922047

  8. Suramin inhibits initiation of defense signaling by systemin, chitosan, and a beta-glucan elicitor in suspension-cultured Lycopersicon peruvianum cells.

    Science.gov (United States)

    Stratmann, J; Scheer, J; Ryan, C A

    2000-08-01

    Systemin-mediated defense signaling in tomato (Lycopersicon esculentum) plants is analogous to the cytokine-mediated inflammatory response in animals. Herein, we report that the initiation of defense signaling in suspension-cultured cells of Lycopersicon peruvianum by the peptide systemin, as well as by chitosan and beta-glucan elicitor from Phytophtora megasperma, is inhibited by the polysulfonated naphtylurea compound suramin, a known inhibitor of cytokine and growth factor receptor interactions in animal cells. Using a radioreceptor assay, we show that suramin interfered with the binding of the systemin analog (125)I-Tyr-2, Ala-15-systemin to the systemin receptor with an IC(50) of 160 microM. Additionally, labeling of the systemin receptor with a photoaffinity analog of systemin was inhibited in the presence of suramin. Receptor-mediated tyrosine phosphorylation of a 48-kDa mitogen-activated protein kinase and alkalinization of the medium of suspension-cultured cells in response to systemin and carbohydrate elicitors were also inhibited by suramin. The inhibition of medium alkalinization by suramin was reversible in the presence of high concentrations of systemin and carbohydrate elicitors. Calyculin A and erythrosin B, intracellular inhibitors of phosphatases and plasma membrane proton ATPases, respectively, both induce medium alkalinization, but neither response was inhibited by suramin. The polysulfonated compound heparin did not inhibit systemin-induced medium alkalinization. NF 007, a suramin derivative, induced medium alkalinization, indicating that neither NF 007 nor heparin interact with elicitor receptors like suramin. The data indicate that cell-surface receptors in plants show some common structural features with animal cytokine and growth factor receptors that can interact with suramin to interfere with ligand binding.

  9. Effects of Polysaccharide Elicitors from Endophytic Fusarium oxysporum Fat9 on the Growth, Flavonoid Accumulation and Antioxidant Property of Fagopyrum tataricum Sprout Cultures.

    Science.gov (United States)

    Zhong, Lingyun; Niu, Bei; Tang, Lin; Chen, Fang; Zhao, Gang; Zhao, Jianglin

    2016-11-25

    The purpose of this study was to evaluate the effects of four different fungal polysaccharides, named water-extracted mycelia polysaccharide (WPS), sodium hydroxide-extracted mycelia polysaccharide (SPS), hydrochloric-extracted mycelia polysaccharide (APS), and exo-polysaccharide (EPS) obtained from the endophytic Fusarium oxysporum Fat9 on the sprout growth, flavonoid accumulation, and antioxidant capacity of tartary buckwheat. Without visible changes in the appearance of the sprouts, the exogenous polysaccharide elicitors strongly stimulated sprout growth and flavonoid production, and the stimulation effect was closely related with the polysaccharide (PS) species and its treatment dosage. With application of 200 mg/L of EPS, 200 mg/L of APS, 150 mg/L of WPS, or 100 mg/L of SPS, the total rutin and quercetin yields of buckwheat sprouts were significantly increased to 41.70 mg/(100 sprouts), 41.52 mg/(100 sprouts), 35.88 mg/(100 sprouts), and 32.95 mg/(100 sprouts), respectively. This was about 1.11 to 1.40-fold compared to the control culture of 31.40 mg/(100 sprouts). Moreover, the antioxidant capacity of tartary buckwheat sprouts was also enhanced after treatment with the four PS elicitors. Furthermore, the present study revealed the polysaccharide elicitation that caused the accumulation of functional flavonoid by stimulating the phenylpropanoid pathway. The application of beneficial fungal polysaccharide elicitors may be an effective approach to improve the nutritional and functional characteristics of tartary buckwheat sprouts.

  10. Effects of Polysaccharide Elicitors from Endophytic Fusarium oxysporum Fat9 on the Growth, Flavonoid Accumulation and Antioxidant Property of Fagopyrum tataricum Sprout Cultures

    Directory of Open Access Journals (Sweden)

    Lingyun Zhong

    2016-11-01

    Full Text Available The purpose of this study was to evaluate the effects of four different fungal polysaccharides, named water-extracted mycelia polysaccharide (WPS, sodium hydroxide-extracted mycelia polysaccharide (SPS, hydrochloric-extracted mycelia polysaccharide (APS, and exo-polysaccharide (EPS obtained from the endophytic Fusarium oxysporum Fat9 on the sprout growth, flavonoid accumulation, and antioxidant capacity of tartary buckwheat. Without visible changes in the appearance of the sprouts, the exogenous polysaccharide elicitors strongly stimulated sprout growth and flavonoid production, and the stimulation effect was closely related with the polysaccharide (PS species and its treatment dosage. With application of 200 mg/L of EPS, 200 mg/L of APS, 150 mg/L of WPS, or 100 mg/L of SPS, the total rutin and quercetin yields of buckwheat sprouts were significantly increased to 41.70 mg/(100 sprouts, 41.52 mg/(100 sprouts, 35.88 mg/(100 sprouts, and 32.95 mg/(100 sprouts, respectively. This was about 1.11 to 1.40-fold compared to the control culture of 31.40 mg/(100 sprouts. Moreover, the antioxidant capacity of tartary buckwheat sprouts was also enhanced after treatment with the four PS elicitors. Furthermore, the present study revealed the polysaccharide elicitation that caused the accumulation of functional flavonoid by stimulating the phenylpropanoid pathway. The application of beneficial fungal polysaccharide elicitors may be an effective approach to improve the nutritional and functional characteristics of tartary buckwheat sprouts.

  11. Asparaginase Erwinia chrysanthemi as a component of a multi-agent chemotherapeutic regimen for the treatment of patients with acute lymphoblastic leukemia who have developed hypersensitivity to E. coli-derived asparaginase.

    Science.gov (United States)

    Figueiredo, Lisa; Cole, Peter D; Drachtman, Richard A

    2016-03-01

    Asparaginase has been a mainstay of therapy in the treatment of acute lymphoblastic leukemia since the 1970s. There are two major preparations available and FDA approved in the United States today, one derived from Escherichia coli and the other from Erwinia chrysanthemi. Erwinia asparaginase is antigenically distinct from and has a considerably shorter biological half-life than E coli asparaginase. Erwinia asparaginase has been used in cases of hypersensitivity to E. coli-derived asparaginases, which has been reported in up to 30% of patients. While PEG asparaginase is increasingly used in front-line therapy for ALL, hypersensitivity still occurs with this preparation, and a change to a non-cross-reactive preparation may be necessary.

  12. Seca dos ponteiros da goiabeira causada por Erwinia psidii: níveis de incidência e aspectos epidemiológicos Guava bacterial blight due to Erwinia psidii: incidence levels and epidemiological aspects

    Directory of Open Access Journals (Sweden)

    Abi Soares Anjos Marques

    2007-01-01

    Full Text Available Um dos fatores limitantes ao cultivo da goiabeira no Brasil é a 'seca dos ponteiros', causada por Erwinia psidii, presente nas regiões Sudeste e Centro-Oeste, onde se concentram grandes áreas produtoras. Considerando a pequena disponibilidade de informações sobre a epidemiologia e níveis de incidência dessa bacteriose, este estudo teve como objetivos: confirmar a distribuição e verificar a dispersão da seca dos ponteiros da goiabeira no Distrito Federal; investigar o efeito da temperatura sobre a multiplicação in vitro de E. psidii; desenvolver um teste de patogenicidade prático e eficiente e avaliar a sobrevivência in vitro da bactéria em diferentes substratos. A doença foi identificada em 56% das propriedades produtoras avaliadas no DF, com 81,9% de correlação entre a presença de sintomas e o diagnóstico laboratorial. A melhor faixa de temperatura para multiplicação de E. psidii foi de 24 a 33 ºC, e a bactéria permaneceu viável por até 120 dias em suspensão em água. A inoculação da bactéria em folhas ou hastes destacadas levou ao aparecimento de sintomas a partir do sétimo dia e mostrou-se eficiente como um teste rápido para se avaliar a patogenicidade de isolados.A major disease that affects guava is 'bacterial blight', caused by Erwinia psidii, which has been reported in Southeastern and Central Regions of Brazil where the major producing areas are located. Considering the lack of information on epidemiology and incidence levels of this disease, the objectives of this study were to confirm the presence and to verify the spread of the disease in Distrito Federal (DF; to determine optimal temperature for in vitro multiplication of E. psidii; to develop a simple and effective method for pathogenicity testing and to evaluate in vitro bacterial survival on different substrates. The disease was detected in 56% of producing orchards evaluated in DF, with a correlation of 81, 9% between presence of symptoms and

  13. Evolutionary divergence of the plant elicitor peptides (Peps) and their receptors: interfamily incompatibility of perception but compatibility of downstream signalling

    KAUST Repository

    Lori, M.

    2015-05-22

    Plant elicitor peptides (Peps) are potent inducers of pattern-triggered immunity and amplify the immune response against diverse pathogens. Peps have been discovered and studied extensively in Arabidopsis and only recently orthologs in maize were also identified and characterized in more detail. Here, the presence of PROPEPs, the Pep precursors, and PEPRs, the Pep receptors, was investigated within the plant kingdom. PROPEPs and PEPRs were identified in most sequenced species of the angiosperms. The conservation and compatibility of the Pep-PEPR-system was analysed by using plants of two distantly related dicot families, Brassicaceae and Solanaceae, and a representative family of monocot plants, the Poaceae. All three plant families contain important crop plants, including maize, rice, tomato, potato, and canola. Peps were not recognized by species outside of their plant family of origin, apparently because of a divergence of the Pep sequences. Three family-specific Pep motifs were defined and the integration of such a motif into the Pep sequence of an unrelated Pep enabled its perception. Transient transformation of Nicotiana benthamiana with the coding sequences of the AtPEPR1 and ZmPEPR1a led to the recognition of Pep peptides of Brassicaceae or Poaceae origin, respectively, and to the proper activation of downstream signalling. It was concluded that signalling machinery downstream of the PEPRs is highly conserved whereas the leucine-rich repeat domains of the PEPRs co-evolved with the Peps, leading to distinct motifs and, with it, interfamily incompatibility.

  14. Defense Priming and Jasmonates: A Role for Free Fatty Acids in Insect Elicitor-Induced Long Distance Signaling

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    Ting Li

    2016-01-01

    Full Text Available Green leaf volatiles (GLV prime plants against insect herbivore attack resulting in stronger and faster signaling by jasmonic acid (JA. In maize this response is specifically linked to insect elicitor (IE-induced signaling processes, which cause JA accumulation not only around the damage site, but also in distant tissues, presumably through the activation of electrical signals. Here, we present additional data further characterizing these distal signaling events in maize. Also, we describe how exposure to GLV increases free fatty acid (fFA levels in maize seedlings, but also in other plants, and how increased fFA levels affect IE-induced JA accumulation. Increased fFA, in particular α-linolenic acid (LnA, caused a significant increase in JA accumulation after IE treatment, while JA induced by mechanical wounding (MW alone was not affected. We also identified treatments that significantly decreased certain fFA level including simulated wind and rain. In such treated plants, IE-induced JA accumulation was significantly reduced when compared to un-moved control plants, while MW-induced JA accumulation was not significantly affected. Since only IE-induced JA accumulation was altered by changes in the fFA composition, we conclude that changing levels of fFA affect primarily IE-induced signaling processes rather than serving as a substrate for JA.

  15. New Synthetic Pyridine Derivate as Potential Elicitor in Production of Isoflavonoids and Flavonoids in Trifolium pratense L. Suspension Culture

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    Marie Kašparová

    2012-01-01

    Full Text Available The production of secondary metabolites in Trifolium pratense L. suspension culture of the family of legume plants (Fabaceae is low, and therefore there was an attempt to increase it by elicitation. New synthetic substance, 2-(2-fluoro-6-nitrobenzylsulfanylpyridine-4-carbothioamide, was tested as elicitor—a substance that showed the best elicitation effect after 48-hour application of 1 μmol L−1 concentration. Maximum contents of genistin (11.60 mg g−1 DW, daidzein (8.31 mg g−1 DW, and genistein (1.50 mg g−1 DW were recorded, and the production of these isoflavonoids thus significantly increased, when compared with the control, by 152%, 151%, and 400%. The maximum content of flavonoids (5.78 mg g−1 DW and the increase in the production by 142%, when compared with the control, were induced by 6-hour application of 100 μmol L−1 concentration. The tested substance showed to be an effective elicitor of phenylpropane metabolism.

  16. A novel exopolysaccharide elicitor from endophytic fungus Gilmaniella sp. AL12 on volatile oils accumulation in Atractylodes lancea

    Science.gov (United States)

    Chen, Fei; Ren, Cheng-Gang; Zhou, Tong; Wei, Yu-Jia; Dai, Chuan-Chao

    2016-10-01

    Endophytes and plants can establish specific long-term symbiosis through the accumulation of secondary metabolites. Previous studies have shown that the endophytic fungus Gilmaniella sp. AL12 can stimulate Atractylodes lancea to produce volatile oils. The purpose of this report is to investigate key factors involved in the stimulation of A. lancea by AL12 and reveal the mechanism. We identified the active component from AL12 as an extracellular mannan with a polymerization degree of 26-42. Differential membrane proteomics of A. lancea was performed by 2D electrophoresis. The results showed that there were significant differences in the expression of 83 proteins. Based on these results, we conclude that AL12 secreted mannan contributes to the antagonistic balance seen in interactions between AL12 and A. lancea. One portion of the mannan was degraded to mannose for hexokinase activation, promoting photosynthesis and energy metabolism, with a potential metabolic fluxes flowing towards terpenoid biosynthesis. The other portion of the mannan directly enhanced autoimmunity of A. lancea through G protein-mediated signal transduction and the mannan-binding lectin pathway. Volatile oil accumulation was ultimately promoted in subsequent defense reactions. This study provides a new perspective on the regulation of secondary metabolites by endophytic fungal elicitors in medicinal plants.

  17. Defense Priming and Jasmonates: A Role for Free Fatty Acids in Insect Elicitor-Induced Long Distance Signaling

    Science.gov (United States)

    Li, Ting; Cofer, Tristan; Engelberth, Marie; Engelberth, Jurgen

    2016-01-01

    Green leaf volatiles (GLV) prime plants against insect herbivore attack resulting in stronger and faster signaling by jasmonic acid (JA). In maize this response is specifically linked to insect elicitor (IE)-induced signaling processes, which cause JA accumulation not only around the damage site, but also in distant tissues, presumably through the activation of electrical signals. Here, we present additional data further characterizing these distal signaling events in maize. Also, we describe how exposure to GLV increases free fatty acid (fFA) levels in maize seedlings, but also in other plants, and how increased fFA levels affect IE-induced JA accumulation. Increased fFA, in particular α-linolenic acid (LnA), caused a significant increase in JA accumulation after IE treatment, while JA induced by mechanical wounding (MW) alone was not affected. We also identified treatments that significantly decreased certain fFA level including simulated wind and rain. In such treated plants, IE-induced JA accumulation was significantly reduced when compared to un-moved control plants, while MW-induced JA accumulation was not significantly affected. Since only IE-induced JA accumulation was altered by changes in the fFA composition, we conclude that changing levels of fFA affect primarily IE-induced signaling processes rather than serving as a substrate for JA. PMID:27135225

  18. Determination of Quantities of Host Protein after Infection with Erwinia amylovora of Apple, Pear And Quince Cultivars

    Directory of Open Access Journals (Sweden)

    Şerife Çetin

    2014-10-01

    Full Text Available Fire blight disease caused by Erwinia amylovora is a destructive bacterial pathogen mainly on pears, apples and quinces from Rosaceae family. In this study, it was aimed determination of total protein amounts in different apple cultivars (Braeburn, Fuji, Gala and Golden, pear cultivars (Santa Maria and Williams and quince cultivars (Eşme and Ekmek in the infections of two virulent E. amylovora strains (Ea234-1 and Ea240-3 according as the time. It was taken leaf samples after leaf inoculation with E. amylovora (108 CFU ml-1 at 24th, 36th and 72nd hours. For verification of the infections, re-isolations were made from bacteria inoculated plants and the agent was identified as E. amylovora by biochemical, physiological and molecular tests. In determining the amounts of total protein and in the SDS-PAGE analyses were used Bradford and Laemmli methods, respectively, and absorbance values of protein extracts derived from the leaf samples taken, were obtained at 595 nm wavelength. According to the findings obtained; after infection of E. amylovora in the apple varieties comparing to controls, total protein concentrations at 24th hours increased and a decrease in the amount of 36th to 72nd hours and Braeburn has the highest protein content was determined. In the pear varieties, while total protein concentrations at 24th and 36th hours increased, a decrease in the amount of 72nd hour, and Santa Maria variety has the highest protein content was detected. In the quince varieties, total protein concentrations at 72th hour increased and Eşme variety has the highest protein content was identified. As a result of SDS-PAGE analysis, protein fractions which have different molecular weights were obtained. The protein bands were defined approximately 55-70 kDa and 35-55 kDa molecule weight on apple and quince varieties, respectively and also approx. 55-70 kDa in pear varieties.

  19. Identification of genes differentially expressed during interaction of resistant and susceptible apple cultivars (Malus x domestica) with Erwinia amylovora.

    Science.gov (United States)

    Baldo, Angela; Norelli, Jay L; Farrell, Robert E; Bassett, Carole L; Aldwinckle, Herb S; Malnoy, Malnoy

    2010-01-04

    The necrogenic enterobacterium, Erwinia amylovora is the causal agent of the fire blight (FB) disease in many Rosaceae species, including apple and pear. During the infection process, the bacteria induce an oxidative stress response with kinetics similar to those induced in an incompatible bacteria-plant interaction. No resistance mechanism to E. amylovora in host plants has yet been characterized, recent work has identified some molecular events which occur in resistant and/or susceptible host interaction with E. amylovora: In order to understand the mechanisms that characterize responses to FB, differentially expressed genes were identified by cDNA-AFLP analysis in resistant and susceptible apple genotypes after inoculation with E. amylovora. cDNA were isolated from M.26 (susceptible) and G.41 (resistant) apple tissues collected 2 h and 48 h after challenge with a virulent E. amylovora strain or mock (buffer) inoculated. To identify differentially expressed transcripts, electrophoretic banding patterns were obtained from cDNAs. In the AFLP experiments, M.26 and G.41 showed different patterns of expression, including genes specifically induced, not induced, or repressed by E. amylovora. In total, 190 ESTs differentially expressed between M.26 and G.41 were identified using 42 pairs of AFLP primers. cDNA-AFLP analysis of global EST expression in a resistant and a susceptible apple genotype identified different major classes of genes. EST sequencing data showed that genes linked to resistance, encoding proteins involved in recognition, signaling, defense and apoptosis, were modulated by E. amylovora in its host plant. The expression time course of some of these ESTs selected via a bioinformatic analysis has been characterized. These data are being used to develop hypotheses of resistance or susceptibility mechanisms in Malus to E. amylovora and provide an initial categorization of genes possibly involved in recognition events, early signaling responses the

  20. Enhancement of expression and apparent secretion of Erwinia chrysanthemi endoglucanase (encoded by celZ) in Escherichia coli B

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, S.; Yomano, L.P.; Saleh, A.Z.; Davis, F.C.; Aldrich, H.C.; Ingram, L.O. [Univ. of Florida, Gainesville, FL (United States)

    1999-06-01

    Escherichia coli B has been engineered as a biocatalyst for the conversion of lignocellulose into ethanol. Previous research has demonstrated that derivatives of E. coli B can produce high levels of Erwinia chrysanthemi endoglucanase (encoded by celZ) as a periplasmic product and that this enzyme can function with commercial fungal cellulase to increase ethanol production. In this study, the authors have demonstrated two methods that improve celZ expression in E. coli B. Initially, with a low-copy-number vector, two E. coli glycolytic gene promoters (gap and eno) were tested and found to be less effective than the original celZ promoter. By screening 18,000 random fragments of Zymomonas mobilis DNA, a surrogate promoter was identified which increased celZ expression up to sixfold. With this promoter, large polar inclusion bodies were clearly evident in the periplasmic space. Sequencing revealed that the most active surrogate promoter is derived from five Sau3A1 fragments, one of which was previously sequenced in Z. mobilis. Visual inspection indicated that this DNA fragment contains at least five putative promoter regions, two of which were confirmed by primer extension analysis. Addition of the out genes from E. chrysanthemi EC16 caused a further increase in the production of active enzyme and facilitated secretion or release of over half of the activity into the extracellular environment. With the most active construct, of a total of 13,000 IU of active enzyme per liter of culture, 7,800 IU was in the supernatant. The total active endoglucanase was estimated to represent 4 to 6% of cellular protein.

  1. Global Effect of Indole-3-Acetic Acid Biosynthesis on Multiple Virulence Factors of Erwinia chrysanthemi 3937▿

    Science.gov (United States)

    Yang, Shihui; Zhang, Qiu; Guo, Jianhua; Charkowski, Amy O.; Glick, Bernard R.; Ibekwe, A. Mark; Cooksey, Donald A.; Yang, Ching-Hong

    2007-01-01

    Production of the plant hormone indole-3-acetic acid (IAA) is widespread among plant-associated microorganisms. The non-gall-forming phytopathogen Erwinia chrysanthemi 3937 (strain Ech3937) possesses iaaM (ASAP16562) and iaaH (ASAP16563) gene homologues. In this work, the null knockout iaaM mutant strain Ech138 was constructed. The IAA production by Ech138 was reduced in M9 minimal medium supplemented with l-tryptophan. Compared with wild-type Ech3937, Ech138 exhibited reduced ability to produce local maceration, but its multiplication in Saintpaulia ionantha was unaffected. The pectate lyase production of Ech138 was diminished. Compared with wild-type Ech3937, the expression levels of an oligogalacturonate lyase gene, ogl, and three endopectate lyase genes, pelD, pelI, and pelL, were reduced in Ech138 as determined by a green fluorescent protein-based fluorescence-activated cell sorting promoter activity assay. In addition, the transcription of type III secretion system (T3SS) genes, dspE (a putative T3SS effector) and hrpN (T3SS harpin), was found to be diminished in the iaaM mutant Ech138. Compared with Ech3937, reduced expression of hrpL (a T3SS alternative sigma factor) and gacA but increased expression of rsmA in Ech138 was also observed, suggesting that the regulation of T3SS and pectate lyase genes by IAA biosynthesis might be partially due to the posttranscriptional regulation of the Gac-Rsm regulatory pathway. PMID:17189441

  2. Efecto de la aplicación de elicitores sobre la producción de 4b-hidroxiwithanólido E, en raíces transformadas de Physalis peruviana L

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    Yineth Piñeros-Castro

    2009-04-01

    Full Text Available Effect of elicitor application on the production of 4-b-hydroxy withanolide E by hairy roots of Physalis peruviana. Objectives: Tostudy the metabolite 4-b-hydroxy withanolide E production by the in vitro culture of golden berry (Physalis peruviana L. transformedroots, and to evaluate the effect of different elicitors on the metabolite production. Materials and methods: Hairy roots of Physalisperuviana L were obtained through infection with Agrobacterium rhizogenes C106. Hairy roots were cultured on Murashige & Skoogliquid medium for four weeks, before being exposed to different concentrations of copper sulfate, salicylic acid and jasmonic acid during24 hours. Metabolite contents were quantified using High Performance Liquid Chromatography. Results: The highest amount of 4-b-hydroxy withanolide E in hairy root tissues (0.323 mg/g of dry roots was obtained after exposing the tissues to 10 mM salicylic acid aselicitor. Conclusions: 4-b-hydroxy withanolide E production in hairy roots was improved by using elicitors such as salicylic acid andcopper sulphate. The highest concentration of the metabolite in hairy roots treated with elicitors was 1.538 times the control concentration(without elicitor treatment.

  3. Analysis of conductance responses during depolymerization of pectate by soft rot Erwinia spp. and other pectolytic bacteria isolated from potato tubers.

    Science.gov (United States)

    Fraaije, B A; Bosveld, M; Van den Bulk, R W; Rombouts, F M

    1997-07-01

    Different bacteria isolated from potato tubers were screened for their pectolytic properties by examining pitting in polypectate agar, recording conductance responses in polypectate medium and performing potato tuber soft rot tests. For bacteria found positive in conductimetry, the role of polygalacturonase (PG) and pectate lyase (PL) in the generation of conductance changes in a polygalacturonic acid (PGA) medium was further analysed using enzyme activity staining after gel electrophoresis and high-performance anion exchange chromatography. The extent of the conductance changes during depolymerization of PGA was dependent on the amounts of galacturonate monomers and oligomers accumulated in the medium. In comparison with an unidentified saprophyte and a Klebsiella strain, both mainly having PL activity, soft rot Erwinia spp. rapidly produced larger conductance responses, due to a combined action of multiple forms of PG and PL. The responses of Erwinia spp. were initially associated with the accumulation of large amounts of monomers and saturated dimers to heptamers, due to PG activity. Subsequently, as well as monomers and saturated dimers, large amounts of unsaturated dimers were also detected, due to PL activity. The role of PG as an important conductimetric factor was also demonstrated for a pectinase preparation derived from Aspergillus niger. Besides detection, automated conductimetric assays in pectate media may also be useful for monitoring of pectolytic activity in pectinase preparations and for screening of pectolytic activity of microorganisms under different media and growth conditions.

  4. Signalling requirements for Erwinia amylovora-induced disease resistance, callose deposition and cell growth in the non-host Arabidopsis thaliana.

    Science.gov (United States)

    Hamdoun, Safae; Gao, Min; Gill, Manroop; Kwon, Ashley; Norelli, John L; Lu, Hua

    2017-07-29

    Erwinia amylovora is the causal agent of the fire blight disease in some plants of the Rosaceae family. The non-host plant Arabidopsis serves as a powerful system for the dissection of mechanisms of resistance to E. amylovora. Although not yet known to mount gene-for-gene resistance to E. amylovora, we found that Arabidopsis activated strong defence signalling mediated by salicylic acid (SA), with kinetics and amplitude similar to that induced by the recognition of the bacterial effector avrRpm1 by the resistance protein RPM1. Genetic analysis further revealed that SA signalling, but not signalling mediated by ethylene (ET) and jasmonic acid (JA), is required for E. amylovora resistance. Erwinia amylovora induces massive callose deposition on infected leaves, which is independent of SA, ET and JA signalling and is necessary for E. amylovora resistance in Arabidopsis. We also observed tumour-like growths on E. amylovora-infected Arabidopsis leaves, which contain enlarged mesophyll cells with increased DNA content and are probably a result of endoreplication. The formation of such growths is largely independent of SA signalling and some E. amylovora effectors. Together, our data reveal signalling requirements for E. amylovora-induced disease resistance, callose deposition and cell fate change in the non-host plant Arabidopsis. Knowledge from this study could facilitate a better understanding of the mechanisms of host defence against E. amylovora and eventually improve host resistance to the pathogen. © 2017 BSPP AND JOHN WILEY & SONS LTD.

  5. The chills as a psychological construct: content universe, factor structure, affective composition, elicitors, trait antecedents, and consequences.

    Science.gov (United States)

    Maruskin, Laura A; Thrash, Todd M; Elliot, Andrew J

    2012-07-01

    We examined the content universe, factor structure, affective composition, elicitors, trait antecedents, and consequences of "the chills." In Study 1, participants described what it means to get the chills. A second sample sorted all references to physical sensations based on similarity. Cluster analysis identified 4 lower order clusters (goosebumps, tingling, coldness, shivers) and 2 higher order clusters ("goosetingles," "coldshivers"). In Study 2, factor analysis of questionnaire data supported a model with lower and higher order factors that corresponded to the Study 1 clusters. Goosetingles and coldshivers were predicted by approach-related traits (e.g., extraversion) and avoidance-related traits (e.g., neuroticism), respectively. In Study 3, analysis of narrative data replicated the goosetingles-coldshivers structure. Relative to coldshivers, goosetingles involved greater awe, surprise, and enjoyment and less disgust, fear, and sadness. In Study 4, analysis of diary data extended the goosetingles-coldshivers structure to between- and within-person levels of analysis. Goosetingles involved positive affects and was elicited by approach-related stimuli, whereas coldshivers involved negative affects and was elicited by avoidance-related stimuli. In Study 5, manipulation of exposure to self-actualization and self-annihilation elicited goosetingles and coldshivers, respectively. Goosetingles and coldshivers had positive and negative effects, respectively, on interpersonal closeness. In sum, diverse forms of evidence converge to indicate that the chills encompasses distinct approach- and avoidance-related constructs. Failure to distinguish these constructs explains null and inconsistent findings in the nascent literature. Goosetingles and coldshivers are posited to serve the function of signaling that an event in the environment is pertinent to one's most deep-seated hopes or fears. PsycINFO Database Record (c) 2012 APA, all rights reserved

  6. Purification and characterization of AsES protein: a subtilisin secreted by Acremonium strictum is a novel plant defense elicitor.

    Science.gov (United States)

    Chalfoun, Nadia R; Grellet-Bournonville, Carlos F; Martínez-Zamora, Martín G; Díaz-Perales, Araceli; Castagnaro, Atilio P; Díaz-Ricci, Juan C

    2013-05-17

    In this work, the purification and characterization of an extracellular elicitor protein, designated AsES, produced by an avirulent isolate of the strawberry pathogen Acremonium strictum, are reported. The defense eliciting activity present in culture filtrates was recovered and purified by ultrafiltration (cutoff, 30 kDa), anionic exchange (Q-Sepharose, pH 7.5), and hydrophobic interaction (phenyl-Sepharose) chromatographies. Two-dimensional SDS-PAGE of the purified active fraction revealed a single spot of 34 kDa and pI 8.8. HPLC (C2/C18) and MS/MS analysis confirmed purification to homogeneity. Foliar spray with AsES provided a total systemic protection against anthracnose disease in strawberry, accompanied by the expression of defense-related genes (i.e. PR1 and Chi2-1). Accumulation of reactive oxygen species (e.g. H2O2 and O2(˙)) and callose was also observed in Arabidopsis. By using degenerate primers designed from the partial amino acid sequences and rapid amplification reactions of cDNA ends, the complete AsES-coding cDNA of 1167 nucleotides was obtained. The deduced amino acid sequence showed significant identity with fungal serine proteinases of the subtilisin family, indicating that AsES is synthesized as a larger precursor containing a 15-residue secretory signal peptide and a 90-residue peptidase inhibitor I9 domain in addition to the 283-residue mature protein. AsES exhibited proteolytic activity in vitro, and its resistance eliciting activity was eliminated when inhibited with PMSF, suggesting that its proteolytic activity is required to induce the defense response. This is, to our knowledge, the first report of a fungal subtilisin that shows eliciting activity in plants. This finding could contribute to develop disease biocontrol strategies in plants by activating its innate immunity.

  7. Convergence and Divergence of Signaling Events in Guard Cells during Stomatal Closure by Plant Hormones or Microbial Elicitors

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    AGURLA SRINIVAS

    2016-08-01

    Full Text Available Dynamic regulation of stomatal aperture is essential for plants to optimize water use and CO2 uptake. Stomatal opening or closure is accompanied by the modulation of guard cell turgor. Among the events leading to stomatal closure by plant hormones or microbial elicitors, three signaling components stand out as the major converging points. These are reactive oxygen species (ROS, cytosolic free Ca2+ and ion channels. Once formed, the ROS and free Ca2+ of guard cells regulate both downstream and upstream events. A major influence of ROS is to increase the levels of NO and cytosolic free Ca2+ in guard cells. Although the rise in NO is an important event during stomatal closure, the available evidences do not support the description of NO as the point of convergence. The rise in ROS and NO would cause an increase of free Ca2+ and modulate ion channels, through a network of events, in such a way that the guard cells lose K+/Cl-/anions. The efflux of these ions decreases the turgor of guard cells and leads to stomatal closure. Thus, ROS, NO and cytosolic free Ca2+ act as points of divergence. The other guard cell components, which are modulated during stomatal closure are G-proteins, cytosolic pH, phospholipids and sphingolipids. However, the current information on the role of these components is not convincing so as to assign them as the points of convergence or divergence. The interrelationships and interactions of ROS, NO, cytosolic pH, and free Ca2+ are quite complex and need further detailed examination. Our review is an attempt to critically assess the current status of information on guard cells, while emphasizing the convergence and divergence of signaling components during stomatal closure. The existing gaps in our knowledge are identified to stimulate further research.

  8. Whole-genome sequence of Pseudomonas fluorescens EK007-RG4, a promising biocontrol agent against a broad range of bacteria, including the fire blight bacterium Erwinia amylovora

    DEFF Research Database (Denmark)

    Habibi, Roghayeh; Tarighi, Saeed; Behravan, Javad

    2017-01-01

    Here, we report the first draft whole-genome sequence of Pseudomonas fluorescens strain EK007-RG4, which was isolated from the phylloplane of a pear tree. P. fluorescens EK007-RG4 displays strong antagonism against Erwinia amylovora, the causal agent for fire blight disease, in addition to several...

  9. Critical Contribution of RAL GTPases to Growth and Survival of Breast Cancer Cells

    Science.gov (United States)

    2007-04-01

    genotypes (20 animals for each group) with a needle coated with a mixture of Gram-negative bacteria (Erwinia carotovora carotovora) and fungi ( Candida ... albicans ). Ten hours later, total RNA was extracted and evaluated by quantitative real-time RT-PCR for Drosomycin (Drs) and ribosomal protein 49 (rp49) gene...RalGTPases: corrupting the exocyst in cancer cells. Trends Cell Biol. 15, 327–332.Cantor, S.B., Urano, T., and Feig, L.A. (1995). Identification and char

  10. Differential induction and suppression of potato 3-hydroxy-3-methylglutaryl coenzyme A reductase genes in response to Phytophthora infestans and to its elicitor arachidonic acid.

    Science.gov (United States)

    Choi, D; Ward, B L; Bostock, R M

    1992-10-01

    Induction of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is essential for the biosynthesis of sesquiterpenoid phytoalexins and steroid derivatives in Solanaceous plants following stresses imposed by wounding and pathogen infection. To better understand this complex step in stress-responsive isoprenoid synthesis, we isolated three classes of cDNAS encoding HMGR (hmg1, hmg2, and hmg3) from a potato tuber library using a probe derived from an Arabidopsis HMGR cDNA. The potato cDNAs had extensive homology in portions of the protein coding regions but had low homology in the 3' untranslated regions. RNA gel blot analyses using gene-specific probes showed that hmg1 was strongly induced in tuber tissue by wounding, but the wound induction was strongly suppressed by treatment of the tissue with the fungal elicitor arachidonic acid or by inoculation with an incompatible or compatible race of the fungal pathogen Phytophtora infestans. The hmg2 and hmg3 mRNAs also accumulated in response to wounding, but in contrast to hmg1, these mRNAs were strongly enhanced by arachidonic acid or inoculation. Inoculation with a compatible race of P. infestans resulted in similar patterns in HMGR gene expression of hmg2 and hmg3 except that the magnitude and rate of the changes in mRNA levels were reduced relative to the incompatible interaction. The differential regulation of members of the HMGR gene family may explain in part the previously reported changes in HMGR enzyme activities following wounding and elicitor treatment. The suppression of hmg1 and the enhancement of hmg2 and hmg3 transcript levels following elicitor treatment or inoculation with the incompatible race parallel the suppression in steroid and stimulation of sesquiterpenoid accumulations observed in earlier investigations. The results are discussed in relation to the hypothesis that there are discrete organizational channels for sterol and sesquiterpene biosynthesis in potato and other Solanaceous species.

  11. Qualidade de uva ‘Isabel’ tratada na pré-colheita com CaCl2 e elicitor à base de biomassa cítrica

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    Leonardo da Silva Santos

    2017-10-01

    Full Text Available O alto índice de degrana e podridão das bagas reduzem a qualidade e elevam as perdas pós-colheita em uvas ‘Isabel’, demandando técnicas de manejo na pré e pós-colheita acessíveis ao pequeno produtor, que mantenham a qualidade e ampliem a vida útil pós-colheita dos cachos. Assim, este trabalho teve por objetivo avaliar o efeito da aplicação na pré-colheita de CaCl2 e elicitor à base de biomassa cítrica em uvas ‘Isabel’ na manutenção da qualidade durante o armazenamento na condição ambiente sob atmosferas ambiente e modificada. O experimento foi conduzido em blocos casualizados a campo, no município de São Vicente Férrer-PE com 8 repetições. Videiras ‘Isabel’ foram tratadas, 28 dias antes da colheita, com: elicitor de Biomassa Cítrica (BC, elicitor de Biomassa Cítrica + CaCl2 (BC+C, CaCl2 (C e Testemunha (T - sem aplicação. Cachos colhidos na maturação comercial foram armazenados em arranjo fatorial 4×2×7, sendo 4 tratamentos (aplicados no campo, 2 condições de armazenamento, atmosferas ambiente (AA e modificada (AM, sob condição ambiente (25±2°C e 75±2% de UR e 7 períodos de avaliação em quatro repetições. A aplicação de CaCl2 e do elicitor BC reduziu o índice de degrana (55 e 75%, respectivamente, a podridão e a perda de massa dos cachos de uva ‘Isabel’. Estes tratamentos, associados ou não, aumentaram a eficiência da AM em manter a qualidade dos cachos. O índice de degrana de uva ‘Isabel’ foi influenciado diretamente pela relação SS/AT, pH e índice de podridão das bagas.

  12. Erwinia amylovora expresses fast and simultaneously hrp/dsp virulence genes during flower infection on apple trees.

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    Doris Pester

    Full Text Available BACKGROUND: Pathogen entry through host blossoms is the predominant infection pathway of the gram-negative bacterium Erwinia amylovora leading to manifestation of the disease fire blight. Like in other economically important plant pathogens, E. amylovora pathogenicity depends on a type III secretion system encoded by hrp genes. However, timing and transcriptional order of hrp gene expression during flower infections are unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using quantitative real-time PCR analyses, we addressed the questions of how fast, strong and uniform key hrp virulence genes and the effector dspA/E are expressed when bacteria enter flowers provided with the full defense mechanism of the apple plant. In non-invasive bacterial inoculations of apple flowers still attached to the tree, E. amylovora activated expression of key type III secretion genes in a narrow time window, mounting in a single expression peak of all investigated hrp/dspA/E genes around 24-48 h post inoculation (hpi. This single expression peak coincided with a single depression in the plant PR-1 expression at 24 hpi indicating transient manipulation of the salicylic acid pathway as one target of E. amylovora type III effectors. Expression of hrp/dspA/E genes was highly correlated to expression of the regulator hrpL and relative transcript abundances followed the ratio: hrpA>hrpN>hrpL>dspA/E. Acidic conditions (pH 4 in flower infections led to reduced virulence/effector gene expression without the typical expression peak observed under natural conditions (pH 7. CONCLUSION/SIGNIFICANCE: The simultaneous expression of hrpL, hrpA, hrpN, and the effector dspA/E during early floral infection indicates that speed and immediate effector transmission is important for successful plant invasion. When this delicate balance is disturbed, e.g., by acidic pH during infection, virulence gene expression is reduced, thus partly explaining the efficacy of acidification in fire blight

  13. Identification of genes differentially expressed during interaction of resistant and susceptible apple cultivars (Malus × domestica) with Erwinia amylovora

    Science.gov (United States)

    2010-01-01

    Background The necrogenic enterobacterium, Erwinia amylovora is the causal agent of the fire blight (FB) disease in many Rosaceaespecies, including apple and pear. During the infection process, the bacteria induce an oxidative stress response with kinetics similar to those induced in an incompatible bacteria-plant interaction. No resistance mechanism to E. amylovora in host plants has yet been characterized, recent work has identified some molecular events which occur in resistant and/or susceptible host interaction with E. amylovora: In order to understand the mechanisms that characterize responses to FB, differentially expressed genes were identified by cDNA-AFLP analysis in resistant and susceptible apple genotypes after inoculation with E. amylovora. Results cDNA were isolated from M.26 (susceptible) and G.41 (resistant) apple tissues collected 2 h and 48 h after challenge with a virulent E. amylovora strain or mock (buffer) inoculated. To identify differentially expressed transcripts, electrophoretic banding patterns were obtained from cDNAs. In the AFLP experiments, M.26 and G.41 showed different patterns of expression, including genes specifically induced, not induced, or repressed by E. amylovora. In total, 190 ESTs differentially expressed between M.26 and G.41 were identified using 42 pairs of AFLP primers. cDNA-AFLP analysis of global EST expression in a resistant and a susceptible apple genotype identified different major classes of genes. EST sequencing data showed that genes linked to resistance, encoding proteins involved in recognition, signaling, defense and apoptosis, were modulated by E. amylovora in its host plant. The expression time course of some of these ESTs selected via a bioinformatic analysis has been characterized. Conclusion These data are being used to develop hypotheses of resistance or susceptibility mechanisms in Malus to E. amylovora and provide an initial categorization of genes possibly involved in recognition events, early

  14. Mutation of the Erwinia amylovora argD gene causes arginine auxotrophy, nonpathogenicity in apples, and reduced virulence in pears.

    Science.gov (United States)

    Ramos, Laura S; Lehman, Brian L; Peter, Kari A; McNellis, Timothy W

    2014-11-01

    Fire blight is caused by Erwinia amylovora and is the most destructive bacterial disease of apples and pears worldwide. In this study, we found that E. amylovora argD(1000)::Tn5, an argD Tn5 transposon mutant that has the Tn5 transposon inserted after nucleotide 999 in the argD gene-coding region, was an arginine auxotroph that did not cause fire blight in apple and had reduced virulence in immature pear fruits. The E. amylovora argD gene encodes a predicted N-acetylornithine aminotransferase enzyme, which is involved in the production of the amino acid arginine. A plasmid-borne copy of the wild-type argD gene complemented both the nonpathogenic and the arginine auxotrophic phenotypes of the argD(1000)::Tn5 mutant. However, even when mixed with virulent E. amylovora cells and inoculated onto immature apple fruit, the argD(1000)::Tn5 mutant still failed to grow, while the virulent strain grew and caused disease. Furthermore, the pCR2.1-argD complementation plasmid was stably maintained in the argD(1000)::Tn5 mutant growing in host tissues without any antibiotic selection. Therefore, the pCR2.1-argD complementation plasmid could be useful for the expression of genes, markers, and reporters in E. amylovora growing in planta, without concern about losing the plasmid over time. The ArgD protein cannot be considered an E. amylovora virulence factor because the argD(1000)::Tn5 mutant was auxotrophic and had a primary metabolism defect. Nevertheless, these results are informative about the parasitic nature of the fire blight disease interaction, since they indicate that E. amylovora cannot obtain sufficient arginine from apple and pear fruit tissues or from apple vegetative tissues, either at the beginning of the infection process or after the infection has progressed to an advanced state. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  15. Ascorbic acid, ultraviolet C rays, and glucose but not hyperthermia are elicitors of human β-defensin 1 mRNA in normal keratinocytes.

    Science.gov (United States)

    Cruz Díaz, Luis Antonio; Flores Miramontes, María Guadalupe; Chávez Hurtado, Paulina; Allen, Kirk; Gonzalez Ávila, Marisela; Prado Montes de Oca, Ernesto

    2015-01-01

    Hosts' innate defense systems are upregulated by antimicrobial peptide elicitors (APEs). Our aim was to investigate the effects of hyperthermia, ultraviolet A rays (UVA), and ultraviolet C rays (UVC) as well as glucose and ascorbic acid (AA) on the regulation of human β-defensin 1 (DEFB1), cathelicidin (CAMP), and interferon-γ (IFNG) genes in normal human keratinocytes (NHK). The indirect in vitro antimicrobial activity against Staphylococcus aureus and Listeria monocytogenes of these potential APEs was tested. We found that AA is a more potent APE for DEFB1 than glucose in NHK. Glucose but not AA is an APE for CAMP. Mild hypo- (35°C) and hyperthermia (39°C) are not APEs in NHK. AA-dependent DEFB1 upregulation below 20 mM predicts in vitro antimicrobial activity as well as glucose- and AA-dependent CAMP and IFNG upregulation. UVC upregulates CAMP and DEFB1 genes but UVA only upregulates the DEFB1 gene. UVC is a previously unrecognized APE in human cells. Our results suggest that glucose upregulates CAMP in an IFN-γ-independent manner. AA is an elicitor of innate immunity that will challenge the current concept of late activation of adaptive immunity of this vitamin. These results could be useful in designing new potential drugs and devices to combat skin infections.

  16. Selective responses of enzymes in the two parallel pathways of rosmarinic acid biosynthetic pathway to elicitors in Salvia miltiorrhiza hairy root cultures.

    Science.gov (United States)

    Zhang, Shuncang; Yan, Yan; Wang, Bangqing; Liang, Zongsuo; Liu, Yan; Liu, Fenghua; Qi, Zhihong

    2014-05-01

    Rosmarinic acid and salvianolic acid B are two important phenolic compounds with therapeutic properties in Salvia miltiorrhiza Bunge. The biosynthesis of rosmarinic acid is initiated by two parallel pathways, namely the phenylpropanoid pathway and the tyrosine-derived pathway. Salvianolic acid B is a structural dimer of rosmarinic acid and is believed to be derived from rosmarinic acid. In the current study, methyl jasmonate (MeJA) and hyphal extracts from fungi were used as elicitors to examine the relationship between enzymes in the two parallel pathways and accumulation of phenolic compounds in S. miltiorrhiza hairy root cultures. The results showed that accumulations of rosmarinic acid, salvianolic acid B and total phenolics were enhanced by MeJA while suppressed by fugal extracts. Responses of enzymes in the tyrosine-derived pathway, at both the gene transcript and enzyme activity levels, showed a better consistency with alterations of phenolic compounds content after the two elicitors treated. Our study implied that compared with enzymes in the phenylpropanoid pathway, enzymes in the tyrosine-derived pathway are more correlated to rosmarinic acid and salvianolic acid B biosynthesis in S. miltiorrhiza hairy roots. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  17. The effect of plant defense elicitors on common bean (Phaseolus vulgaris L. growth and yield in absence or presence of spider mite (Tetranychus urticae Koch infestation

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    Farouk S.

    2011-09-01

    Full Text Available BackgroundThe common bean plants "Phaseolus vulgaris L." is frequently attacked by the two spotted spider mite (TSSM Tetranychus urticae, causing a substantial decrease in bean plant growth and yield as well as leaflet structure. Therefore, for commercial bean cultivation in the field controlling TSSM infection is necessary. ResultsFoliar application of salicylic acid (SA or methyl jasmonate (MeJA on common bean plants before or after two spotted spider mite infestation proved to be effective in reducing infestations. In most concentrations these elicitors significantly improved common bean plant growth i.e. had a positive effect on plant height, number of branches, shoot dry weight and leaf area per plant and bean yield. SA at 100 mg/l had the strongest positive effect. Moreover, application of elicitors significantly altered leaflet anatomical characters i.e. increased thickness of leaflet blade, thickness of palisade and spongy parenchyma as well as thickness of midrib region of the leaflet and changed the dimension of vascular bundles. Alternatively, TSSM infestation had the opposite effect on these leaflet anatomical characters.ConclusionWe conclude that SA or MeJA could be used for controlling TSSM infestation, to improve plant growth and to improve bean yield in the field.

  18. Ascorbic Acid, Ultraviolet C Rays, and Glucose but not Hyperthermia Are Elicitors of Human β-Defensin 1 mRNA in Normal Keratinocytes

    Directory of Open Access Journals (Sweden)

    Luis Antonio Cruz Díaz

    2015-01-01

    Full Text Available Hosts’ innate defense systems are upregulated by antimicrobial peptide elicitors (APEs. Our aim was to investigate the effects of hyperthermia, ultraviolet A rays (UVA, and ultraviolet C rays (UVC as well as glucose and ascorbic acid (AA on the regulation of human β-defensin 1 (DEFB1, cathelicidin (CAMP, and interferon-γ (IFNG genes in normal human keratinocytes (NHK. The indirect in vitro antimicrobial activity against Staphylococcus aureus and Listeria monocytogenes of these potential APEs was tested. We found that AA is a more potent APE for DEFB1 than glucose in NHK. Glucose but not AA is an APE for CAMP. Mild hypo- (35°C and hyperthermia (39°C are not APEs in NHK. AA-dependent DEFB1 upregulation below 20 mM predicts in vitro antimicrobial activity as well as glucose- and AA-dependent CAMP and IFNG upregulation. UVC upregulates CAMP and DEFB1 genes but UVA only upregulates the DEFB1 gene. UVC is a previously unrecognized APE in human cells. Our results suggest that glucose upregulates CAMP in an IFN-γ-independent manner. AA is an elicitor of innate immunity that will challenge the current concept of late activation of adaptive immunity of this vitamin. These results could be useful in designing new potential drugs and devices to combat skin infections.

  19. Chemical Elicitor-Induced Modulation of Antioxidant Metabolism and Enhancement of Secondary Metabolite Accumulation in Cell Suspension Cultures of Scrophularia kakudensis Franch

    Directory of Open Access Journals (Sweden)

    Abinaya Manivannan

    2016-03-01

    Full Text Available Scrophularia kakudensis is an important medicinal plant with pharmaceutically valuable secondary metabolites. To develop a sustainable source of naturaceuticals with vital therapeutic importance, a cell suspension culture was established in S. kakudensis for the first time. Friable calli were induced from the leaf explants cultured on a Murashige and Skoog (MS medium containing 3.0 mg·L−1 6-benzyladenine (BA in a combination with 2 mg·L−1 2,4-dichlorophenoxy acetic acid (2,4-D. From the callus cultures, a cell suspension culture was initiated and the cellular differentiation was investigated. In addition, the effect of biotic elicitors such as methyl jasmonate (MeJa, salicylic acid (SA, and sodium nitroprusside (SNP on the accumulation of secondary metabolites and antioxidant properties was demonstrated. Among the elicitors, the MeJa elicited the accumulation of total phenols, flavonoids, and acacetin, a flavonoid compound with multiple pharmaceutical values. Similarly, the higher concentrations of the MeJa significantly modulated the activities of antioxidant enzymes and enhanced the scavenging potentials of free radicals of cell suspension extracts. Overall, the outcomes of this study can be utilized for the large scale production of pharmaceutically important secondary metabolites from S. kakudensis through cell suspension cultures.

  20. Chemical Elicitor-Induced Modulation of Antioxidant Metabolism and Enhancement of Secondary Metabolite Accumulation in Cell Suspension Cultures of Scrophularia kakudensis Franch.

    Science.gov (United States)

    Manivannan, Abinaya; Soundararajan, Prabhakaran; Park, Yoo Gyeong; Jeong, Byoung Ryong

    2016-03-18

    Scrophularia kakudensis is an important medicinal plant with pharmaceutically valuable secondary metabolites. To develop a sustainable source of naturaceuticals with vital therapeutic importance, a cell suspension culture was established in S. kakudensis for the first time. Friable calli were induced from the leaf explants cultured on a Murashige and Skoog (MS) medium containing 3.0 mg·L(-1) 6-benzyladenine (BA) in a combination with 2 mg·L(-1) 2,4-dichlorophenoxy acetic acid (2,4-D). From the callus cultures, a cell suspension culture was initiated and the cellular differentiation was investigated. In addition, the effect of biotic elicitors such as methyl jasmonate (MeJa), salicylic acid (SA), and sodium nitroprusside (SNP) on the accumulation of secondary metabolites and antioxidant properties was demonstrated. Among the elicitors, the MeJa elicited the accumulation of total phenols, flavonoids, and acacetin, a flavonoid compound with multiple pharmaceutical values. Similarly, the higher concentrations of the MeJa significantly modulated the activities of antioxidant enzymes and enhanced the scavenging potentials of free radicals of cell suspension extracts. Overall, the outcomes of this study can be utilized for the large scale production of pharmaceutically important secondary metabolites from S. kakudensis through cell suspension cultures.

  1. Ascorbic Acid, Ultraviolet C Rays, and Glucose but not Hyperthermia Are Elicitors of Human β-Defensin 1 mRNA in Normal Keratinocytes

    Science.gov (United States)

    Cruz Díaz, Luis Antonio; Flores Miramontes, María Guadalupe; Allen, Kirk; Gonzalez Ávila, Marisela; Prado Montes de Oca, Ernesto

    2015-01-01

    Hosts' innate defense systems are upregulated by antimicrobial peptide elicitors (APEs). Our aim was to investigate the effects of hyperthermia, ultraviolet A rays (UVA), and ultraviolet C rays (UVC) as well as glucose and ascorbic acid (AA) on the regulation of human β-defensin 1 (DEFB1), cathelicidin (CAMP), and interferon-γ (IFNG) genes in normal human keratinocytes (NHK). The indirect in vitro antimicrobial activity against Staphylococcus aureus and Listeria monocytogenes of these potential APEs was tested. We found that AA is a more potent APE for DEFB1 than glucose in NHK. Glucose but not AA is an APE for CAMP. Mild hypo- (35°C) and hyperthermia (39°C) are not APEs in NHK. AA-dependent DEFB1 upregulation below 20 mM predicts in vitro antimicrobial activity as well as glucose- and AA-dependent CAMP and IFNG upregulation. UVC upregulates CAMP and DEFB1 genes but UVA only upregulates the DEFB1 gene. UVC is a previously unrecognized APE in human cells. Our results suggest that glucose upregulates CAMP in an IFN-γ-independent manner. AA is an elicitor of innate immunity that will challenge the current concept of late activation of adaptive immunity of this vitamin. These results could be useful in designing new potential drugs and devices to combat skin infections. PMID:25815330

  2. Complexes cobalt(II, zinc(II and copper(II with some newly synthesized benzimidazole derivatives and their antibacterial activity

    Directory of Open Access Journals (Sweden)

    S. O. PODUNAVAC-KUZMANOVIC

    1999-05-01

    Full Text Available The preparation and properties of some complexes of cobalt(II, zinc(II and copper(II with several newly synthesized benzimidazole derivatives (L are reported. The complexes, of the general formula [MCl2L2] (M=Co(II, Zn(II and [CuCl2L(H2O], have a tetrahedral structure. The complexes were characterized by elemental analysis, molar conductivity, magnetic susceptibility measurements, IR and absorption electronic spectra. The antibacterial activitiy of the benzimidazoles and their complexes was evaluated against Erwinia carotovora subsp. carotovora and Erwinia amylovora. The complexes were found to be more toxic than the ligands.

  3. Systems level analysis of two-component signal transduction systems in Erwinia amylovora: Role in virulence, regulation of amylovoran biosynthesis and swarming motility

    Directory of Open Access Journals (Sweden)

    Sundin George W

    2009-05-01

    Full Text Available Abstract Background Two-component signal transduction systems (TCSTs, consisting of a histidine kinase (HK and a response regulator (RR, represent a major paradigm for signal transduction in prokaryotes. TCSTs play critical roles in sensing and responding to environmental conditions, and in bacterial pathogenesis. Most TCSTs in Erwinia amylovora have either not been identified or have not yet been studied. Results We used a systems approach to identify TCST and related signal transduction genes in the genome of E. amylovora. Comparative genomic analysis of TCSTs indicated that E. amylovora TCSTs were closely related to those of Erwinia tasmaniensis, a saprophytic enterobacterium isolated from apple flowers, and to other enterobacteria. Forty-six TCST genes in E. amylovora including 17 sensor kinases, three hybrid kinases, 20 DNA- or ligand-binding RRs, four RRs with enzymatic output domain (EAL-GGDEF proteins, and two kinases were characterized in this study. A systematic TCST gene-knockout experiment was conducted, generating a total of 59 single-, double-, and triple-mutants. Virulence assays revealed that five of these mutants were non-pathogenic on immature pear fruits. Results from phenotypic characterization and gene expression experiments indicated that several groups of TCST systems in E. amylovora control amylovoran biosynthesis, one of two major virulence factors in E. amylovora. Both negative and positive regulators of amylovoran biosynthesis were identified, indicating a complex network may control this important feature of pathogenesis. Positive (non-motile, EnvZ/OmpR, negative (hypermotile, GrrS/GrrA, and intermediate regulators for swarming motility in E. amylovora were also identified. Conclusion Our results demonstrated that TCSTs in E. amylovora played major roles in virulence on immature pear fruit and in regulating amylovoran biosynthesis and swarming motility. This suggested presence of regulatory networks governing

  4. Lon protease modulates virulence traits in Erwinia amylovora by direct monitoring of major regulators and indirectly through the Rcs and Gac-Csr regulatory systems.

    Science.gov (United States)

    Lee, Jae Hoon; Ancona, Veronica; Zhao, Youfu

    2017-05-16

    Lon, an ATP-dependent protease in bacteria, influences diverse cellular processes by degrading damaged, misfolded and short-lived regulatory proteins. In this study, we characterized the effects of lon mutation and determined the molecular mechanisms underlying Lon-mediated virulence regulation in Erwinia amylovora, an enterobacterial pathogen of apple. Erwinia amylovora depends on the type III secretion system (T3SS) and the exopolysaccharide (EPS) amylovoran to cause disease. Our results showed that mutation of the lon gene led to the overproduction of amylovoran, increased T3SS gene expression and the non-motile phenotype. Western blot analyses showed that mutation in lon directly affected the accumulation and stability of HrpS/HrpA and RcsA. Mutation in lon also indirectly influenced the expression of flhD, hrpS and csrB through the accumulation of the RcsA/RcsB proteins, which bind to the promoter of these genes. In addition, lon expression is under the control of CsrA, possibly at both the transcriptional and post-transcriptional levels. Although mutation in csrA abolished both T3SS and amylovoran production, deletion of the lon gene in the csrA mutant only rescued amylovoran production, but not T3SS. These results suggest that CsrA might positively control both T3SS and amylovoran production partly by suppressing Lon, whereas CsrA may also play a critical role in T3SS by affecting unknown targets. © 2017 BSPP AND JOHN WILEY & SONS LTD.

  5. Animals as disgust elicitors

    DEFF Research Database (Denmark)

    Kasperbauer, Tyler Joshua

    2015-01-01

    This paper attempts to explain how and why nonhuman animals elicit disgust in human beings. I argue that animals elicit disgust in two ways. One is by triggering disease–protection mechanisms, and the other is by eliciting mortality salience, or thoughts of death. I discuss how these two types...... of disgust operate and defend their conceptual and theoretical coherence against common objections. I also outline an explanatory challenge for disgust researchers. Both types of disgust indicate that a wide variety of animals produce aversive and avoidant reactions in human beings. This seems somewhat odd......, given the prominence of animals in human lives. The challenge, then, is explaining how humans cope with the presence of animals. I propose, as a hypothesis for further exploration, that we cope with animals, and our disgust responses to them, by attributing mental states that mark them as inferior...

  6. Tissue-specific gene-expression patterns of genes associated with thymol/carvacrol biosynthesis in thyme (Thymus vulgaris L.) and their differential changes upon treatment with abiotic elicitors

    DEFF Research Database (Denmark)

    Majdi, Mohammad; Malekzadeh-Mashhady, Atefe; Maroufi, Asad

    2017-01-01

    of the regulation of monoterpene biosynthesis in thyme, the expression of genes related to thymol and carvacrol biosynthesis in different tissues and in response to abiotic elicitors was analyzed. Methyl jasmonate (MeJA), salicylic acid (SA), trans-cinnamic acid (tCA) and UV-C irradiation were applied to T. vulgare...

  7. Evidence that generation of inositol 1,4,5-trisphosphate and hydrolysis of phosphatidylinositol 4,5-bisphosphate are rapid responses following addition of fungal elicitor which induces phytoalexin synthesis in lucerne (Medicago sativa) suspension culture cells.

    Science.gov (United States)

    Walton, T J; Cooke, C J; Newton, R P; Smith, C J

    1993-05-01

    Treatment of lucerne suspension culture cells with glycoprotein elicitor from the phytopathogenic fungus Verticillium albo-atrum R & B triggers Ca(2+)-mediated induction of antimicrobial secondary metabolites termed phytoalexins. The present study investigated the possible role of polyphosphoinositide signal transduction in phytoalexin elicitation. Within 1 min of addition of elicitor to lucerne suspension culture cells we found a 100-160% (15-25 pmol/g fresh wt) increase in the level of compound with chromatographic and electrophoretic properties expected for an inositol trisphosphate (InsP3) and which was strongly bound by an inositol 1,4,5-trisphosphate (Ins(1,4,5)P3)-specific binding protein; after 3 min the level of this compound had fallen below that observed prior to elicitor challenge. In 32P-prelabelled cells, the relative proportion of radioactivity which cochromatographed with phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) was found to have decreased by 48% 1 min after elicitor addition and that rapid depletion of membrane lipid radioactivity was specific to this lipid fraction. The rapid, transient increase in level of Ins(1,4,5)P3 and concomitant fall in PtdIns(4,5)P2 suggests that Ins(1,4,5)P3 generated by hydrolysis of PtdIns(4,5)P2 may provide a Ca(2+)-mobilizing signal in phytoalexin elicitation in lucerne.

  8. Identification of target genes of the bZIP transcription factor OsTGAP1, whose overexpression causes elicitor-induced hyperaccumulation of diterpenoid phytoalexins in rice cells.

    Directory of Open Access Journals (Sweden)

    Koji Miyamoto

    Full Text Available Phytoalexins are specialised antimicrobial metabolites that are produced by plants in response to pathogen attack. Momilactones and phytocassanes are the major diterpenoid phytoalexins in rice and are synthesised from geranylgeranyl diphosphate, which is derived from the methylerythritol phosphate (MEP pathway. The hyperaccumulation of momilactones and phytocassanes due to the hyperinductive expression of the relevant biosynthetic genes and the MEP pathway gene OsDXS3 in OsTGAP1-overexpressing (OsTGAP1ox rice cells has previously been shown to be stimulated by the chitin oligosaccharide elicitor. In this study, to clarify the mechanisms of the elicitor-stimulated coordinated hyperinduction of these phytoalexin biosynthetic genes in OsTGAP1ox cells, transcriptome analysis and chromatin immunoprecipitation with next-generation sequencing were performed, resulting in the identification of 122 OsTGAP1 target genes. Transcriptome analysis revealed that nearly all of the momilactone and phytocassane biosynthetic genes, which are clustered on chromosomes 4 and 2, respectively, and the MEP pathway genes were hyperinductively expressed in the elicitor-stimulated OsTGAP1ox cells. Unexpectedly, none of the clustered genes was included among the OsTGAP1 target genes, suggesting that OsTGAP1 did not directly regulate the expression of these biosynthetic genes through binding to each promoter region. Interestingly, however, several OsTGAP1-binding regions were found in the intergenic regions among and near the cluster regions. Concerning the MEP pathway genes, only OsDXS3, which encodes a key enzyme of the MEP pathway, possessed an OsTGAP1-binding region in its upstream region. A subsequent transactivation assay further confirmed the direct regulation of OsDXS3 expression by OsTGAP1, but other MEP pathway genes were not included among the OsTGAP1 target genes. Collectively, these results suggest that OsTGAP1 participates in the enhanced accumulation of

  9. Nucleoporin NUP88/MOS7 is required for manifestation of phenotypes associated with the Arabidopsis CHITIN ELICITOR RECEPTOR KINASE1 mutant cerk1-4.

    Science.gov (United States)

    Genenncher, Bianca; Lipka, Volker; Petutschnig, Elena K; Wiermer, Marcel

    2017-05-04

    Arabidopsis nucleoporin MOS7/NUP88 was identified in a forward-genetic screen for components that contribute to auto-immunity of the deregulated Resistance (R) gene mutant snc1, and is required for immunity to biotrophic and hemi-biotrophic pathogens. In a recent study, we showed that MOS7 is also essential to mount a full defense response against the necrotrophic fungal pathogen Botrytis cinerea, suggesting that MOS7 modulates plant defense responses to different types of pathogenic microbes. Here, we extend our analyses of MOS7-dependent plant immune responses and report the genetic requirement of MOS7 for manifestation of phenotypes associated with the CHITIN ELICITOR RECEPTOR KINASE1 (CERK1) mutant cerk1-4.

  10. Impact of Exogenous Elicitors on Artemisinin Production and Trichome Density in Artemisia annua L. under Subtropical Conditions

    Directory of Open Access Journals (Sweden)

    Alka Jagdish DANGASH

    2014-09-01

    Full Text Available Artemisinin is a sesquiterpene lactone found in Artemisia annua having many medicinal properties. Therefore the factors affecting trichome initiation are important. In the present study, several strategies have been adapted to increase artemisinin production by treating them with nutrients, hormones and elicitors. Abscisic acid, Gibberellic acid (GA3, a combination of GA3+IAA (Gibberellic acid+indole acetic acid, Chitosan, Methyl jasmonate, Acetyl salicylic acid, Lead acetate, sodium chloride, and Nanozime were sprayed on plant at regular intervals. The glandular trichomes of leaves from Artemisia annua (Asteraceae were examined by light and scanning electron microscopy and the percentage artemisnin content was analyzed by HPTLC. Maximum artemisinin content % and trichome index (0.128 was found when methy jasmonate was applied and minimum artemisinin content % and trichome index was reported in NaCl & acetyl salicylic acid.

  11. Soluble and wall-bound phenolics and phenolic polymers in Musa acuminata roots exposed to elicitors from Fusarium oxysporum f.sp. cubense.

    Science.gov (United States)

    de Ascensao, Ana R F D C; Dubery, Ian A

    2003-07-01

    The accumulation of soluble and wall-bound phenolics and phenolic polymers in Musa acuminata roots exposed to cell wall-derived elicitor from the pathogen, Fusarium oxysporum, f.sp. cubense, race four, was investigated. The root tissue from the banana cultivar "Goldfinger" was found to respond strongly and rapidly towards the elicitor through the increased synthesis of phenolic compounds. Following elicitation, the conjugated and non-conjugated phenolic metabolites in the induced root tissue were extracted and quantified. Induced phenolic synthesis was rapid and reached near maximum values after 16 h. High-performance liquid chromatography revealed both compositional and quantitative differences between induced phenolics (p-coumaric, ferulic, and sinapic acids) and those constitutively present (p-coumaric- and ferulic acid). In addition, vanillic acid was found in the ester-bound fraction and protocatechuic acid in the cell-wall bound fraction of elicited tissue. The deposition and accumulation kinetics of polymerized phenolic monomers as lignin and lignin-like polymers was quantified over a time period of 0-36 h and found to reach maximum values after 24 h. Ionization difference UV spectra of lignin indicated compositional differences in the newly synthesized lignin fraction and correlated with increased concentrations of ferulic acid and sinapic acids esters. The results show that the increased flux through the phenylpropanoid pathway resulted in the synthesis of cinnamic acid and benzoic acid derivatives that were esterified and incorporated into the cell wall fraction as part of the anti-microbial defenses activated in the root tissue.

  12. The coat protein of Alternanthera mosaic virus is the elicitor of a temperature-sensitive systemic necrosis in Nicotiana benthamiana, and interacts with a host boron transporter protein

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyoun-Sub, E-mail: hyounlim@cnu.ac.kr [Department of Applied Biology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Nam, Jiryun, E-mail: jilyoon@naver.com [Department of Applied Biology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Seo, Eun-Young, E-mail: sey22@cnu.ac.kr [Department of Applied Biology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Nam, Moon, E-mail: moonlit51@cnu.ac.kr [Department of Applied Biology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Vaira, Anna Maria, E-mail: a.vaira@ivv.cnr.it [Floral and Nursery Plants Research Unit, US National Arboretum, USDA-ARS, 10300 Baltimore Avenue B-010A, Beltsville, MD 20705 (United States); Istituto di Virologia Vegetale, CNR, Strada delle Cacce 73, Torino 10135 (Italy); Bae, Hanhong, E-mail: hanhongbae@ynu.ac.kr [School of Biotechnology, Yeungnam University, Geongsan 712-749 (Korea, Republic of); Jang, Chan-Yong, E-mail: sunbispirit@gmail.com [Department of Applied Biology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lee, Cheol Ho, E-mail: chlee1219@hanmail.net [Department of Chemical and Biological Engineering, Seokyoung University, Seoul 136-704 (Korea, Republic of); Kim, Hong Gi, E-mail: hgkim@cnu.ac.kr [Department of Applied Biology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Roh, Mark, E-mail: marksroh@gmail.com [Floral and Nursery Plants Research Unit, US National Arboretum, USDA-ARS, 10300 Baltimore Avenue B-010A, Beltsville, MD 20705 (United States); Laboratory of Floriculture and Plant Physiology, School of Bio-Resource Science, Dankook University, Cheonan, Chungnam 330-714 (Korea, Republic of); Hammond, John, E-mail: john.hammond@ars.usda.gov [Floral and Nursery Plants Research Unit, US National Arboretum, USDA-ARS, 10300 Baltimore Avenue B-010A, Beltsville, MD 20705 (United States)

    2014-03-15

    Different isolates of Alternanthera mosaic virus (AltMV; Potexvirus), including four infectious clones derived from AltMV-SP, induce distinct systemic symptoms in Nicotiana benthamiana. Virus accumulation was enhanced at 15 °C compared to 25 °C; severe clone AltMV 3-7 induced systemic necrosis (SN) and plant death at 15 °C. No interaction with potexvirus resistance gene Rx was detected, although SN was ablated by silencing of SGT1, as for other cases of potexvirus-induced necrosis. Substitution of AltMV 3-7 coat protein (CP{sub SP}) with that from AltMV-Po (CP{sub Po}) eliminated SN at 15 °C, and ameliorated symptoms in Alternanthera dentata and soybean. Substitution of only two residues from CP{sub Po} [either MN(13,14)ID or LA(76,77)IS] efficiently ablated SN in N. benthamiana. CP{sub SP} but not CP{sub Po} interacted with Arabidopsis boron transporter protein AtBOR1 by yeast two-hybrid assay; N. benthamiana homolog NbBOR1 interacted more strongly with CP{sub SP} than CP{sub Po} in bimolecular fluorescence complementation, and may affect recognition of CP as an elicitor of SN. - Highlights: • Alternanthera mosaic virus CP is an elicitor of systemic necrosis in N. benthamiana. • Virus-induced systemic necrosis is enhanced at 15 °C compared to 25 °C. • Induction of systemic necrosis is dependent on as few as two CP amino acid residues. • These residues are at subunit interfaces within the same turn of the virion helix. • Inducer/non-inducer CPs interact differentially with a boron transporter protein.

  13. Produção de isomaltulose a partir da transformação enzimática da sacarose, utilizando-se Erwinia sp D12 imobilizada com alginato de cálcio Production of isomaltulose from enzymatic transformation of sucrose, using Erwinia sp D12 immobilized with calcium alginate

    Directory of Open Access Journals (Sweden)

    Ana Lúcia Leite Moraes

    2005-03-01

    Full Text Available A glicosiltransferase de Erwinia sp D12 é capaz de converter a sacarose em isomaltulose (6-o-alfa-glicopiranosil D-frutofuranose, um açúcar alternativo que apresenta baixo potencial cariogênico, e que pode ser utilizado em chocolates, gomas de mascar e balas. A isomaltulose é também utilizada na produção de isomalte, uma mistura de açúcar álcool, de baixo valor calórico e baixo potencial cariogênico. No estudo da influência dos componentes do meio de cultivo, na produção de glicosiltransferase, em frascos agitados, foi obtido maior atividade da enzima (12,8 unidades de atividade/mL do meio de cultura em meio de cultura A constituído de melaço 12% (p/v de sólidos solúveis totais, peptona 4% (p/v e extrato de carne 0,4% (p/v. No estudo do efeito do tempo e da temperatura na fermentação da linhagem de Erwinia sp D12, em fermentador New Brunswick de 3L, contendo meio de cultura A, foi obtida maior atividade de glicosiltransferase (15,6 unidades de atividade/ mL de meio de cultura na fase exponencial de crescimento após 8 horas de fermentação a 30ºC. Na produção de isomaltulose a partir da sacarose utilizando-se células de Erwinia sp D12 imobilizadas em alginato de cálcio, estudou-se o efeito da temperatura (25 - 35ºC e da concentração de substrato (12,5 - 60% p/v. Foi obtido um rendimento em torno de 50% de isomaltulose, com soluções de sacarose entre 20-30% (p/v a 35ºC. Concentrações em excesso de sacarose (ao redor de 40% p/v afetaram a atividade da célula imobilizada, diminuindo a conversão de sacarose em isomaltulose. O xarope de isomaltulose foi purificado através de cromatografia de troca iônica e o eluato cristalizado por abaixamento de temperatura. Os cristais apresentaram 91,39% de isomaltulose.The glucosyltransferase of Erwinia sp D12 is able to convert sucrose into isomaltulose (6-0-alpha-D-glucopyranosyl-D-fructofuranose, an alternative sugar which presents low cariogenic potential, and can be

  14. Carotenoid biosynthesis in bacteria: In vitro studies of a crt/bch transcription factor from Rhodobacter capsulatus and carotenoid enzymes from Erwinia herbicola

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, David Allen [Univ. of California, Berkeley, CA (United States)

    1992-11-01

    A putative transcription factor in Rhodobactor capsulatus which binds upstream of the crt and bch pigment biosynthesis operons and appears to play a role in the adaptation of the organism from the aerobic to the anaerobic-photosynthetic growth mode was characterized. Chapter 2 describes the identification of this factor through an in vitro mobility shift assay, as well as the determination of its binding properties and sequence specificity. Chapter 3 focuses on the isolation of this factor. Biochemistry of later carotenoid biosynthesis enzymes derived from the non-photosynthetic bacterium, Erwinia herbicola. Chapter 4 describes the separate overexpression and in vitro analysis of two enzymes involved in the main sequence of the carotenoid biosynthesis pathway, lycopene cyclase and 5-carotene hydroxylase. Chapter 5 examines the overexpression and enzymology of functionally active zeaxanthin glucosyltransferase, an enzyme which carries out a more unusual transformation, converting a carotenoid into its more hydrophilic mono- and diglucoside derivatives. In addition, amino acid homology with other glucosyltransferases suggests a putative binding site for the UDP-activated glucose substrate.

  15. HopX1 in Erwinia amylovora functions as an avirulence protein in apple and is regulated by HrpL.

    Science.gov (United States)

    Bocsanczy, A M; Schneider, D J; DeClerck, G A; Cartinhour, S; Beer, S V

    2012-02-01

    Fire blight is a devastating disease of rosaceous plants caused by the Gram-negative bacterium Erwinia amylovora. This pathogen delivers virulence proteins into host cells utilizing the type III secretion system (T3SS). Expression of the T3SS and of translocated and secreted substrates is activated by the alternative sigma factor HrpL, which recognizes hrp box promoters upstream of regulated genes. A collection of hidden Markov model (HMM) profiles was used to identify putative hrp boxes in the genome sequence of Ea273, a highly virulent strain of E. amylovora. Among potential virulence factors preceded by putative hrp boxes, two genes previously known as Eop3 and Eop2 were characterized. The presence of functionally active hrp boxes upstream of these two genes was confirmed by β-glucuronidase (GUS) assays. Deletion mutants of the latter candidate genes, renamed hopX1(Ea) and hopAK1(Ea), respectively, did not differ in virulence from the wild-type strain when assayed in pear fruit and apple shoots. The hopX1(Ea) deletion mutant of Ea273, complemented with a plasmid overexpressing hopX1(E)(a), suppressed the development of the hypersensitivity response (HR) when inoculated into Nicotiana benthamiana; however, it contributed to HR in Nicotiana tabacum and significantly reduced the progress of disease in apple shoots, suggesting that HopX1(Ea) may act as an avirulence protein in apple shoots.

  16. T3SS-dependent differential modulations of the jasmonic acid pathway in susceptible and resistant genotypes of Malus spp. challenged with Erwinia amylovora.

    Science.gov (United States)

    Dugé De Bernonville, Thomas; Gaucher, Matthieu; Flors, Victor; Gaillard, Sylvain; Paulin, Jean-Pierre; Dat, James F; Brisset, Marie-Noëlle

    2012-06-01

    Fire blight is a bacterial disease of Maloideae caused by Erwinia amylovora (Ea). This necrogenic enterobacterium uses a type III secretion system (T3SS) to inject type III effectors into the plant cells to cause disease on its susceptible hosts, including economically important crops like apple and pear. The expressions of marker genes of the salicylic acid (SA) and jasmonic acid (JA) defense regulation pathways were monitored by RT-qPCR in leaves of two apple genotypes, one susceptible and one resistant, challenged with a wild type strain, a T3SS-deficient strain or water. The transcriptional data taken together with hormone level measurements indicated that the SA pathway was similarly induced in both apple genotypes during infection by Ea. On the contrary, the data clearly showed a strong T3SS-dependent down-regulation of the JA pathway in leaves of the susceptible genotype but not in those of the resistant one. Accordingly, methyl-jasmonate treated susceptible plants displayed an increased resistance to Ea. Bacterial mutant analysis indicated that JA manipulation by Ea mainly relies on the type III effector DspA/E. Taken together, our data suggest that the T3SS-dependent down-regulation of the JA pathway is a critical step in the infection process of Malus spp. by Ea. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  17. Phylogenetic analysis of PR genes in some pome fruit species with the emphasis on transcriptional analysis and ROS response under Erwinia amylovora inoculation in apple.

    Science.gov (United States)

    Hassani, Maryam; Salami, Seyed Alireza; Nasiri, Jaber; Abdollahi, Hamid; Ghahremani, Zahra

    2016-02-01

    Attempts were made to identify eight pathogenesis related (PR) genes (i.e., PR-1a, PR3-ch1, PR3-Ch2, PR3-Ch3, PR3-Ch4, PR3-Ch5, PR-5 and PR-8) from 27 genotypes of apple, quince and pear, which are induced in response to inoculation with the pathogen Erwinia amylovora, the causal agent of fire blight. Totally, 32 PR genes of different families were obtained, excepting PR3-Ch2 (amplified only in apple) and PR3-Ch4 (amplified only in apple and pear), the others were successfully amplified in all the genotypes of apple, quince and pear. Evolutionary, the genes of each family exhibited significant homology with each other, as the corresponded phylogenetic neighbor-joining-based dendrograms were taken into consideration. Meanwhile, according to the expression assay, it was deduced that the pathogen activity can significantly affect the expression levels of some selected PR genes of PR3-Ch2, PR3-Ch4, PR3-Ch5 and particularly Cat I in both resistant (MM-111) and semi-susceptible (MM-106) apple rootstocks. Lastly, it was concluded that the pathogen E. amylovora is able to stimulate ROS response, particularly using generation of hydrogen peroxide (H2O2) in both aforementioned apple rootstock.

  18. {open_quotes}Horizontal{close_quotes} gene transfer from a transgenic potato line to a bacterial pathogen (Erwinia chrysanthemi) occurs - if at all - at an extremely low frequency

    Energy Technology Data Exchange (ETDEWEB)

    Schlueter, K.; Fuetterer, J.; Potrykus, I. [Institute of Plant Sciences, Zuerich (Switzerland)

    1995-10-01

    The frequency of possible {open_quotes}horizontal{close_quotes} gene transfer between a plant and a tightly associated bacterial pathogen was studied in a model system consisting of transgenic Solanum tuberosum, containing a {beta}-lactamase gene linked to a pBR322 origin of replication, and Erwinia chrysanthemi. This experimental system offers optimal conditions for the detection of possible horizontal gene transfer events, even when they occur at very low frequency. Horizontal gene transfer was not detected under conditions mimicking a {open_quotes}natural{close_quotes} infection. The gradual, stepwise alteration of artificial, positive control conditions to idealized natural conditions, however, allowed the characterization of factors that affected gene transfer, and revealed a gradual decrease of the gene transfer frequency from 6.3 x 10{sup -2} under optimal control conditions to a calculated 2.0 x 10{sub -17} under idealized natural conditions. These data, in combination with other published studies, argue that horizontal gene transfer is so rare as to be essentially irrelevant to any realistic assessment of the risk involved in release experiments involving transgenic plants. 22 refs., 3 figs., 2 tabs.

  19. Virulence of Erwinia amylovora, a prevalent apple pathogen: Outer membrane proteins and type III secreted effectors increase fitness and compromise plant defenses.

    Science.gov (United States)

    Holtappels, Michelle; Noben, Jean-Paul; Valcke, Roland

    2016-09-01

    Until now, no data are available on the outer membrane (OM) proteome of Erwinia amylovora, a Gram-negative plant pathogen, causing fire blight in most of the members of the Rosaceae family. Since the OM forms the interface between the bacterial cell and its environment it is in direct contact with the host. Additionally, the type III secretion system, embedded in the OM, is a pathogenicity factor of E. amylovora. To assess the influence of the OM composition and the secretion behavior on virulence, a 2D-DIGE analysis and gene expression profiling were performed on a high and lower virulent strain, both in vitro and in planta. Proteome data showed an increase in flagellin for the lower virulent strain in vitro, whereas, in planta several interesting proteins were identified as being differently expressed between both the strains. Further, gene expression of nearly all type III secreted effectors was elevated for the higher virulent strain, both in vitro and in planta. As a first, we report that several characteristics of virulence can be assigned to the OM proteome. Moreover, we demonstrate that secreted proteins prove to be the important factors determining differences in virulence between the strains, otherwise regarded as homogeneous on a genome level. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Flavohaemoglobin HmpX from Erwinia chrysanthemi confers nitrosative stress tolerance and affects the plant hypersensitive reaction by intercepting nitric oxide produced by the host.

    Science.gov (United States)

    Boccara, Martine; Mills, Catherine E; Zeier, Jürgen; Anzi, Chiara; Lamb, Chris; Poole, Robert K; Delledonne, Massimo

    2005-07-01

    Host cells respond to infection by generating nitric oxide (NO) as a cytotoxic weapon to facilitate killing of invading microbes. Bacterial flavohaemoglobins are well-known scavengers of NO and play a crucial role in protecting animal pathogens from nitrosative stress during infection. Erwinia chrysanthemi, which causes macerating diseases in a wide variety of plants, possesses a flavohaemoglobin (HmpX) whose function in plant pathogens has remained unclear. Here we show that HmpX consumes NO and prevents inhibition by NO of cell respiration, indicating a role in protection from nitrosative stress. Furthermore, infection of Saintpaulia ionantha plants with an HmpX-deficient mutant of E. chrysanthemi revealed that the lack of NO scavenging activity causes the accumulation of unusually high levels of NO in host tissue and triggers hypersensitive cell death. Introduction of the wild-type hmpX gene in an incompatible strain of Pseudomonas syringae had a dramatic effect on the hypersensitive cell death in soya bean cell suspensions, and markedly reduced the development of macroscopic symptoms in Arabidopsis thaliana plants. These observations indicate that HmpX not only protects against nitrosative stress but also attenuates host hypersensitive reaction during infection by intercepting NO produced by the plant for the execution of the hypersensitive cell death programme.

  1. Characterization of a tonB mutation in Erwinia chrysanthemi 3937: TonB(Ech) is a member of the enterobacterial TonB family.

    Science.gov (United States)

    Enard, C; Expert, D

    2000-08-01

    The pectinolytic enterobacterium Erwinia chrysanthemi 3937 causes a systemic disease in its natural host, the African violet (Saintpaulia: ionantha). It produces two structurally unrelated siderophores, chrysobactin and achromobactin. Chrysobactin makes a large contribution to invasive growth of the bacterium in its host. Insertion mutants of a chrysobactin-defective strain were constructed and screened on the universal CAS-agar medium used for siderophore detection. A set of mutants affected in the production of achromobactin were identified. This paper describes a mutant affected in the transport of all the ferrisiderophores used by the bacterium as iron sources. Molecular analysis revealed that the insertion mutation disrupts the tonB gene. The predicted Er. chrysanthemi TonB protein has a molecular mass of 27600 Da and shares 20-58% identity with the TonB proteins from 20 other bacterial species. The pathogenicity of the tonB mutant was assessed by inoculation of African violets. The impairment in the spread of symptoms was similar in the tonB mutant to that in chrysobactin-defective mutants. However, the pectinolytic activity, the major pathogenicity determinant in Er. chrysanthemi, appeared to be stimulated twofold in the tonB mutant.

  2. The minimal gene set member msrA, encoding peptide methionine sulfoxide reductase, is a virulence determinant of the plant pathogen Erwinia chrysanthemi.

    Science.gov (United States)

    Hassouni, M E; Chambost, J P; Expert, D; Van Gijsegem, F; Barras, F

    1999-02-02

    Peptide methionine sulfoxide reductase (MsrA), which repairs oxidized proteins, is present in most living organisms, and the cognate structural gene belongs to the so-called minimum gene set [Mushegian, A. R. & Koonin, E. V., (1996) Proc. Natl. Acad. Sci. USA 93, 10268-10273]. In this work, we report that MsrA is required for full virulence of the plant pathogen Erwinia chrysanthemi. The following differences were observed between the wild-type and a MsrA- mutant: (i) the MsrA- mutant was more sensitive to oxidative stress; (ii) the MsrA- mutant was less motile on solid surface; (iii) the MsrA- mutant exhibited reduced virulence on chicory leaves; and (iv) no systemic invasion was observed when the MsrA- mutant was inoculated into whole Saintpaulia ionantha plants. These results suggest that plants respond to virulent pathogens by producing active oxygen species, and that enzymes repairing oxidative damage allow virulent pathogens to survive the host environment, thereby supporting the theory that active oxygen species play a key role in plant defense.

  3. Biogenesis of Fe/S proteins and pathogenicity: IscR plays a key role in allowing Erwinia chrysanthemi to adapt to hostile conditions.

    Science.gov (United States)

    Rincon-Enriquez, Gabriel; Crété, Patrice; Barras, Frédéric; Py, Béatrice

    2008-03-01

    The Erwinia chrysanthemi genome is predicted to encode three systems, Nif, Isc and Suf, known to assist Fe/S cluster biogenesis and the CsdAE cysteine desulphurase. Single iscU, hscA and fdx mutants were found sensitive to paraquat and exhibited reduced virulence on both chicory leaves and Arabidopsis thaliana. Depletion of the whole Isc system led to a pleiotropic phenotype, including sensitivity to both paraquat and 2,2'-dipyridyl, auxotrophies for branched-chain amino acids, thiamine, nicotinic acid, and drastic alteration in virulence. IscR was able to suppress all of the phenotypes listed above in a sufC-dependent manner while depletion of the Isc system led to IscR-dependent activation of the suf operon. No virulence defects were found associated with csdA or nifS mutations. Surprisingly, we found that the sufC mutant was virulent against A. thaliana, whereas its virulence had been found altered in Saintpaulia. Collectively, these results lead us to propose that E. chrysanthemi possess the Fe/S biogenesis strategy suited to the physico-chemical conditions encountered in its host upon infection. In this view, the IscR regulator, which controls both Isc and Suf, is predicted to play a major role in the ability of E. chrysanthemi to colonize a wide array of different plants.

  4. Following spread of fire blight in Western, Central and Southern Europe by molecular differentiation of Erwinia amylovora strains with PFGE analysis.

    Science.gov (United States)

    Jock, Susanne; Donat, Victoria; López, Maria M; Bazzi, Carlo; Geider, Klaus

    2002-02-01

    Fire blight has been detected recently in several areas of northern Spain and north-eastern Italy. To follow spread of the disease within Europe, more than 120 Erwinia amylovora strains isolated from 1957-1900 in England, France, Germany, The Netherlands, Belgium, Poland, Italy and Spain were assayed using pulsed-field gel electrophoresis (PFGE) analysis of genomic DNA after XbaI digestion. Pattern types Pt1 and Pt4 were found for strains from England. Pt1 was also found in central Europe and eastern France, Pt4 in western France. Pt2 appeared first in Egypt, from where strains with this pattern disseminated northwards as far as into the Balkans. Pt3 was typical for northern France and Belgium. Strains from Spain displayed the pattern types Pt3 and Pt4. In Italy, Pt2 was found in the south-eastern areas, Pt3 in the north-eastern areas, and Pt1 was found very recently in orchards adjacent to the Austrian border, together with Pt3. Despite barely controlled trade with fire blight host plants and associated plant products within Europe, the PFGE patterns of the E. amylovora isolates were ordered indicating sequential spread. On the other hand, the appearance of Pt3 in northern Italy and central Spain can be explained by the import of contaminated plants by nurseries.

  5. In-vitro antibacterial activities of the essential oils of aromatic plants against Erwinia herbicola (Lohnis and pseudomonas putida (Kris Hamilton

    Directory of Open Access Journals (Sweden)

    Pandey Abhay K.

    2012-01-01

    Full Text Available This study was designed to examine in vitro antibacterial activities of essential oils extracted from 53 aromatic plants of Gorakhpur Division (UP, INDIA for the control of two phytopathogenic bacteria namely Erwinia herbicola and Pseudomonas putida causing several post-harvest diseases in fruits and vegetables. Out of 53 oils screened, 8 oils such as Chenopodium ambrosioides, Citrus aurantium, Clausena pentaphylla, Hyptis suaveolens, Lippia alba, Mentha arvensis, Ocimum sanctum and Vitex negundo completely inhibited the growth of test bacteria. Furthermore MIC & MBC values of C. ambrosioides oil were least for Erw. herbicola (0.25 & 2.0 μl/ml and Ps. putida (0.12 & 1.0 μl/ml respectively than other 7 oils as well as Agromycin and Streptomycin drugs used in current study. GC and GC-MS analysis of Chenopodium oil revealed presence of 125 major and minor compounds, out of them, 14 compounds were recognized. The findings concluded that Chenopodium oil may be regarded as safe antibacterial agent for the management of post-harvest diseases of fruits and vegetables.

  6. ORF Alignment: NC_004547 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_004547 gi|50122189 >1ek9A 1 407 23 422 2e-51 ... ref|YP_051356.1| agglutination pr...otein [Erwinia carotovora subsp. atroseptica ... SCRI1043] emb|CAG76165.1| agglutination protein [Erw

  7. Anti-bacterial activity of Guizotia scabra L. and Maesa lanceolata L ...

    African Journals Online (AJOL)

    Medicinal plants roots, barks, leaves and flowers were collected from the Institute of Higher Education (called INES-Ruhengeri) botanical garden established near Volcanoes of Rwanda. Dried crude extracts were prepared in the laboratory for anti-microbial activity assay on identified Erwinia carotovora from infected ...

  8. introduction aerobic mesophilic bacteria associated with irish potato

    African Journals Online (AJOL)

    Bacterial soft rot is one of the most common potato diseases in the tropics and induces quick and heavy spoilage losses. Its causal bacterium, Erwinia carotovora, has been extensively studied (Harrison and Nielson, 1990). Among the fungi reported to be associated with dry rot of potato,. Fusarium solani has been reported ...

  9. African Journal of Food, Agriculture, Nutrition and Development - Vol ...

    African Journals Online (AJOL)

    Anti-bacterial activity of Guizotia scabra L. and Maesa lanceolata L. extracts on Erwinia carotovora L. responsible for Irish potato soft rot in Rwanda · EMAIL FREE ... Nutrient composition, pest and microbial status and effects of discarded biscuits on the growth performance, carcass characteristics and economic profiles of ...

  10. Impact of transgenic potatoes expressing anti-bacterial agents on bacterial endophytes is comparable with the effects of plant genotype, soil type and pathogen infection

    NARCIS (Netherlands)

    Rasche, F.; Velvis, H.; Zachow, C.; Berg, G.; Elsas, van J.D.; Sessitsch, A.

    2006-01-01

    1. Blackleg and soft rot disease of potatoes Solanum tuberosum L., mainly caused by the bacterial pathogen Erwinia carotovora ssp. atrospetica (Eca), lead to enormous yield losses world-wide. Genetically modified (GM) potatoes producing anti-bacterial agents, such as cecropin/attacin and T4

  11. Impact of transgenic potatoes expressing anti-bacterial agents on bacterial endophytes is comparable with the effects of plant genotype, soil type and pathogen infection

    NARCIS (Netherlands)

    Rasche, F; Velvis, H; Zachow, C; Berg, G; Van Elsas, JD; Sessitsch, A

    1. Blackleg and soft rot disease of potatoes Solanum tuberosum L., mainly caused by the bacterial pathogen Erwinia carotovora ssp. atrospetica (Eca), lead to enormous yield losses world-wide. Genetically modified (GM) potatoes producing anti-bacterial agents, such as cecropin/attacin and T4

  12. Síntese de trans-resveratrol e controle de podridão em maçãs com uso de elicitores em pós-colheita Synthesis of trans-resveratrol and rotting control in apples with use of elicitors in post-harvest

    Directory of Open Access Journals (Sweden)

    Cláudia Kaehler Sautter

    2008-09-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da aplicação de elicitores abióticos na biossíntese de resveratrol e na indução de resistência à podridão póscolheita de maçãs 'Gala' e 'Fuji'. Foram realizados os tratamentos: radiação ultravioleta, fosfito e acibenzolar-Smetil - aplicados antes do armazenamento - e ozônio - aplicado intermitente durante o armazenamento. As condições de armazenamento foram: 'Gala', 1,5 kPa de O2 e 2,5 kPa de CO2, a 0,5±0,1ºC, por oito meses, e 'Fuji', 1,0 kPa de O2 e fosfito> irradiação UV-C> ozônio. Na maçã 'Gala', o fosfito reduz a ocorrência de podridão, porém, em ambas as cultivares, não há correlação entre síntese de trans-resveratrol e controle de podridão.The objective of this study was evaluate the effect of the application of abiotic elicitors of resveratrol in 'Gala' and 'Fuji' apples, and rotting control. The treatment was with ultraviolet irradiation, phosphite and acibenzolar-Smethyl, applied before controlled atmosphere storage and ozone, applied so intermittently during storage. The storage conditions were: 'Gala' (1.5 kPa O2 and 2.5 kPa CO2, at 0.5±0.1°C by eight months and 'Fuji' (1.0 kPa O2 and phosphite>UV-C irradiation>ozone. There isn't correlation between synthesis of trans-resveratrol and rotting control, but the phosphite controlled rot in 'Gala'.

  13. Acetic acid acts as an elicitor exerting a chitosan-like effect on xanthone biosynthesis in Hypericum perforatum L. root cultures.

    Science.gov (United States)

    Valletta, Alessio; De Angelis, Giulia; Badiali, Camilla; Brasili, Elisa; Miccheli, Alfredo; Di Cocco, Maria Enrica; Pasqua, Gabriella

    2016-05-01

    Acetic acid acts as a signal molecule, strongly enhancing xanthone biosynthesis in Hypericum perforatum root cultures. This activity is specific, as demonstrated by the comparison with other short-chain monocarboxylic acids. We have recently demonstrated that Hypericum perforatum root cultures constitutively produce xanthones at higher levels than the root of the plant and that they respond to chitosan (CHIT) elicitation with a noteworthy increase in xanthone production. In the present study, CHIT was administered to H. perforatum root cultures using three different elicitation protocols, and the increase in xanthone production was evaluated. The best results (550 % xanthone increase) were obtained by subjecting the roots to a single elicitation with 200 mg l(-1) CHIT and maintaining the elicitor in the culture medium for 7 days. To discriminate the effect of CHIT from that of the solvent, control experiments were performed by administering AcOH alone at the same concentration used for CHIT solubilization. Unexpectedly, AcOH caused an increase in xanthone production comparable to that observed in response to CHIT. Feeding experiments with (13)C-labeled AcOH demonstrated that this compound was not incorporated into the xanthone skeleton. Other short-chain monocarboxylic acids (i.e., propionic and butyric acid) have little or no effect on the production of xanthones. These results indicate that AcOH acts as a specific signal molecule, able to greatly enhance xanthone biosynthesis in H. perforatum root cultures.

  14. Rhizophagus irregularis as an elicitor of rosmarinic acid and antioxidant production by transformed roots of Ocimum basilicum in an in vitro co-culture system.

    Science.gov (United States)

    Srivastava, Shivani; Conlan, Xavier A; Cahill, David M; Adholeya, Alok

    2016-11-01

    Arbuscular mycorrhiza is a symbiotic association formed between plant roots and soil borne fungi that alter and at times improve the production of secondary metabolites. Detailed information is available on mycorrhizal development and its influence on plants grown under various edapho-climatic conditions, however, very little is known about their influence on transformed roots that are rich reserves of secondary metabolites. This raises the question of how mycorrhizal colonization progresses in transformed roots grown in vitro and whether the mycorrhizal fungus presence influences the production of secondary metabolites. To fully understand mycorrhizal ontogenesis and its effect on root morphology, root biomass, total phenolics, rosmarinic acid, caffeic acid and antioxidant production under in vitro conditions, a co-culture was developed between three Agrobacterium rhizogenes-derived, elite-transformed root lines of Ocimum basilicum and Rhizophagus irregularis. We found that mycorrhizal ontogenesis in transformed roots was similar to mycorrhizal roots obtained from an in planta system. Mycorrhizal establishment was also found to be transformed root line-specific. Colonization of transformed roots increased the concentration of rosmarinic acid, caffeic acid and antioxidant production while no effect was observed on root morphological traits and biomass. Enhancement of total phenolics and rosmarinic acid in the three mycorrhizal transformed root lines was found to be transformed root line-specific and age dependent. We reveal the potential of R. irregularis as a biotic elicitor in vitro and propose its incorporation into commercial in vitro secondary metabolite production via transformed roots.

  15. Waterborne signaling primes the expression of elicitor-induced genes and buffers the oxidative responses in the brown alga Laminaria digitata.

    Directory of Open Access Journals (Sweden)

    François Thomas

    Full Text Available As marine sessile organisms, seaweeds must respond efficiently to biotic and abiotic challenges in their natural environment to reduce the fitness consequences of wounds and oxidative stress. This study explores the early steps of the defense responses of a large marine brown alga (the tangle kelp Laminaria digitata and investigates its ability to transmit a warning message to neighboring conspecifics. We compared the early responses to elicitation with oligoguluronates in laboratory-grown and harvested wild individuals of L. digitata. We followed the release of H₂O₂ and the concomitant production of volatile organic compounds. We also monitored the kinetics of expression of defense-related genes following the oxidative burst. Laboratory-grown algae were transplanted in kelp habitats to further evaluate their responses to elicitation after a transient immersion in natural seawater. In addition, a novel conditioning procedure was established to mimic field conditions in the laboratory. Our experiments showed that L. digitata integrates waterborne cues present in the kelp bed and/or released from elicited neighboring plants. Indeed, the exposure to elicited conspecifics changes the patterns of oxidative burst and volatile emissions and potentiates this kelp for faster induction of genes specifically regulated in response to oligoguluronates. Thus, waterborne signals shape the elicitor-induced responses of kelps through a yet unknown mechanism reminiscent of priming in land plants.

  16. Transcriptional profiling of rice treated with MoHrip1 reveal the function of protein elicitor in enhancement of disease resistance and plant growth

    Directory of Open Access Journals (Sweden)

    Shun Lv

    2016-12-01

    Full Text Available MoHrip1 is a protein elicitor isolated from Magnaporthe oryzae and was found to induce blast-resistance in rice. To investigate the comprehensive functions of MoHrip1, next-generation sequencing (NGS-based digital gene expression (DGE profiling was performed to collect the transcriptional data of differentially expressed genes induced by MoHrip1. A total of 308 genes were identified with differential expression, and 80 genes were predicted to be induced specifically by MoHrip1. Among these 308 genes, a series of genes associated with the salicylic acid (SA pathway, phytoalexin, transcription factors and pathogen-related proteins were identified. Both the SA signaling pathway and the gibberellin (GA pathway were activated, while the jasmonic acid (JA signaling pathway was repressed. The contents of endogenous SA and GA and the morphological characteristics of the rice after treatment were measured to provide evidence supporting the predictions made based on the DGE data. The 80 genes mentioned above might be candidate genes for studying interactions with MoHrip1. The transcriptional data provided global effect information in rice induced by MoHrip1, and all the results demonstrated that MoHrip1 could induce pathogen resistance and promote plant growth by regulating the contents of SA and GA directly or indirectly.

  17. An endophytic Streptomyces sp. strain DHV3-2 from diseased root as a potential biocontrol agent against Verticillium dahliae and growth elicitor in tomato (Solanum lycopersicum).

    Science.gov (United States)

    Cao, Peng; Liu, Chongxi; Sun, Pengyu; Fu, Xuepeng; Wang, Shaoxian; Wu, Fengzhi; Wang, Xiangjing

    2016-12-01

    Plant endophytes play important roles in biocontrol of plant diseases. Actinomycetes are used for biocontrol of fungal diseases caused by Verticillium dahliae. Many studies have focused on the endophytic actinomycetes isolated from the roots of healthy plants, but few on those from the roots of diseased plants. In the present research, actinomycetes were isolated from the roots of diseased and healthy tomato plants, respectively. The results showed that, in total, 86 endophytic actinomycetes were isolated for screening of their antimicrobial activities, 8 of which showed antagonism to V. dahliae in vitro. Among the 8 antagonistic strains, 5 (out of 36) were from the roots of diseased plants, with inhibition diameter zones ranging from 11.2 to 18.2 mm, whereas 3 (out of 50) were from the roots of healthy plants, with inhibition diameter zones ranging from 11.5 to 15.5 mm. Endophytic strain DHV3-2 was isolated from the root of a diseased plant and demonstrated a potent effect against V. dahliae and other pathogenic fungi by showing the largest inhibition diameter zones among all the eight antagonistic strains. Thus, strain DHV3-2 was chosen to investigate its biological control efficacies in vivo. Further study showed that the disease incidence and disease severity indices of tomato Verticillium wilt decreased significantly (P biocontrol agent against V. dahliae and growth elicitor in tomato.

  18. The cinnamyl alcohol dehydrogenase (CAD gene family in flax (Linum usitatissimum L.: Insight from expression profiling of cads induced by elicitors in cultured flax cells

    Directory of Open Access Journals (Sweden)

    Eom Hee Seung

    2016-01-01

    Full Text Available Cinnamyl alcohol dehydrogenase (CAD is a key enzyme in the biosynthesis of lignin and lignans as it catalyzes the final step of monolignol biosynthesis, using NADPH as a cofactor. In higher plants, CAD is encoded by a multigene family consisting of three major classes. Based on the recently released flax (Linum usitatissimum L. whole-genome sequences, in this study we identified six CAD family genes that contain an ADH_N domain and an ADH_zinc_N domain, which suggests that the putative flax CADs (LuCADs are zinc-dependent alcohol dehydrogenases and members of the plant CAD family. In addition, expression analysis using quantitative real-time PCR revealed spatial variations in the expression of LuCADs in different organs. Comparative analysis between LuCAD enzymatic activity and LuCAD transcripts indicates that the variation of LuCAD enzymatic activities by elicitors is reflected by transcription of LuCADs in flax suspension-cultured cells. Taken together, our genome-wide analysis of CAD genes and the expression profiling of these genes provide valuable information for understanding the function of CADs, and will assist future studies on the physiological role of monolignols associated with plant defense.

  19. A Novel WRKY transcription factor is required for induction of PR-1a gene expression by salicylic acid and bacterial elicitors.

    Science.gov (United States)

    van Verk, Marcel C; Pappaioannou, Dimitri; Neeleman, Lyda; Bol, John F; Linthorst, Huub J M

    2008-04-01

    PR-1a is a salicylic acid-inducible defense gene of tobacco (Nicotiana tabacum). One-hybrid screens identified a novel tobacco WRKY transcription factor (NtWRKY12) with specific binding sites in the PR-1a promoter at positions -564 (box WK(1)) and -859 (box WK(2)). NtWRKY12 belongs to the class of transcription factors in which the WRKY sequence is followed by a GKK rather than a GQK sequence. The binding sequence of NtWRKY12 (WK box TTTTCCAC) deviated significantly from the consensus sequence (W box TTGAC[C/T]) shown to be recognized by WRKY factors with the GQK sequence. Mutation of the GKK sequence in NtWRKY12 into GQK or GEK abolished binding to the WK box. The WK(1) box is in close proximity to binding sites in the PR-1a promoter for transcription factors TGA1a (as-1 box) and Myb1 (MBSII box). Expression studies with PR-1a promoterbeta-glucuronidase (GUS) genes in stably and transiently transformed tobacco indicated that NtWRKY12 and TGA1a act synergistically in PR-1a expression induced by salicylic acid and bacterial elicitors. Cotransfection of Arabidopsis thaliana protoplasts with 35SNtWRKY12 and PR-1aGUS promoter fusions showed that overexpression of NtWRKY12 resulted in a strong increase in GUS expression, which required functional WK boxes in the PR-1a promoter.

  20. Surface survival and internalization of salmonella through natural cracks on developing cantaloupe fruits, alone or in the presence of the melon wilt pathogen Erwinia tracheiphila.

    Science.gov (United States)

    Gautam, Dhiraj; Dobhal, Shefali; Payton, Mark E; Fletcher, Jacqueline; Ma, Li Maria

    2014-01-01

    Outbreaks of foodborne illness attributed to the consumption of Salmonella-tainted cantaloupe have occurred repeatedly, but understanding of the ecology of Salmonella on cantaloupe fruit surfaces is limited. We investigated the interactions between Salmonella enterica Poona, the plant pathogenic bacterium Erwinia tracheiphila, and cantaloupe fruit. Fruit surfaces were inoculated at the natural cracking stage by spreading S. enterica and E. tracheiphila, 20 µl at 107 cfu/ml, independently or together, over a 2×2 cm rind area containing a crack. Microbial and microscopic analyses were performed at 0, 9 and 24 days post inoculation (DPI). Even at 24 DPI (fruit maturity) S. enterica was detected on 14% and 40% of the fruit inoculated with S. enterica alone and the two-pathogen mixture, respectively. However, the population of S. enterica declined gradually after initial inoculation. E. tracheiphila, inoculated alone or together with Salmonella, caused watersoaked lesions on cantaloupe fruit; but we could not conclude in this study that S. enterica survival on the fruit surface was enhanced by the presence of those lesions. Of fruit inoculated with E. tracheiphila alone and sampled at 24 DPI, 61% had watersoaked lesions on the surface. In nearly half of those symptomatic fruits the watersoaking extended into the sub-rind mesocarp, and E. tracheiphila was recovered from that tissue in 50% of the symptomatic fruit. In this work, E. tracheiphila internalized through natural cracks on developing fruits. S. enterica was never detected in the fruit interior (ca. 2-3 mm below rind surface) under the limited conditions of our experiments, but the possibility that it, or other human pathogens that contaminate fresh produce, might also do so should be investigated under a wider range of conditions and produce types.

  1. Surface survival and internalization of salmonella through natural cracks on developing cantaloupe fruits, alone or in the presence of the melon wilt pathogen Erwinia tracheiphila.

    Directory of Open Access Journals (Sweden)

    Dhiraj Gautam

    Full Text Available Outbreaks of foodborne illness attributed to the consumption of Salmonella-tainted cantaloupe have occurred repeatedly, but understanding of the ecology of Salmonella on cantaloupe fruit surfaces is limited. We investigated the interactions between Salmonella enterica Poona, the plant pathogenic bacterium Erwinia tracheiphila, and cantaloupe fruit. Fruit surfaces were inoculated at the natural cracking stage by spreading S. enterica and E. tracheiphila, 20 µl at 107 cfu/ml, independently or together, over a 2×2 cm rind area containing a crack. Microbial and microscopic analyses were performed at 0, 9 and 24 days post inoculation (DPI. Even at 24 DPI (fruit maturity S. enterica was detected on 14% and 40% of the fruit inoculated with S. enterica alone and the two-pathogen mixture, respectively. However, the population of S. enterica declined gradually after initial inoculation. E. tracheiphila, inoculated alone or together with Salmonella, caused watersoaked lesions on cantaloupe fruit; but we could not conclude in this study that S. enterica survival on the fruit surface was enhanced by the presence of those lesions. Of fruit inoculated with E. tracheiphila alone and sampled at 24 DPI, 61% had watersoaked lesions on the surface. In nearly half of those symptomatic fruits the watersoaking extended into the sub-rind mesocarp, and E. tracheiphila was recovered from that tissue in 50% of the symptomatic fruit. In this work, E. tracheiphila internalized through natural cracks on developing fruits. S. enterica was never detected in the fruit interior (ca. 2-3 mm below rind surface under the limited conditions of our experiments, but the possibility that it, or other human pathogens that contaminate fresh produce, might also do so should be investigated under a wider range of conditions and produce types.

  2. Control of fire blight (Erwinia amylovora on apple trees with trunk-injected plant resistance inducers and antibiotics and assessment of induction of pathogenesis-related protein genes

    Directory of Open Access Journals (Sweden)

    Srđan G. Aćimović

    2015-02-01

    Full Text Available Management of fire blight is complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. Even though successful in control, preventive antibiotic sprays also affect non-target bacteria, aiding the selection for resistance which could ultimately be transferred to the pathogen Erwinia amylovora. Trunk injection is a target-precise pesticide delivery method that utilizes tree xylem to distribute injected compounds. Trunk injection could decrease antibiotic usage in the open environment and increase the effectiveness of compounds in fire blight control. In field experiments, after 1-2 apple tree injections of either streptomycin, potassium phosphites (PH or acibenzolar-S-methyl (ASM, significant reduction of blossom and shoot blight symptoms was observed compared to water- or non-injected control trees. Overall disease suppression with streptomycin was lower than typically observed following spray applications to flowers. Trunk injection of oxytetracycline resulted in excellent control of shoot blight severity, suggesting that injection is a superior delivery method for this antibiotic. Injection of both ASM and PH resulted in the significant induction of PR-1, PR-2 and PR-8 protein genes in apple leaves indicating induction of systemic acquired resistance (SAR under field conditions. The time separating SAR induction and fire blight symptom suppression indicated that various defensive compounds within the SAR response were synthesized and accumulated in the canopy. ASM and PH suppressed fire blight even after cessation of induced gene expression. With the development of injectable formulations and optimization of doses and injection schedules, the injection of protective compounds could serve as an effective option for fire blight control.

  3. Criteria for efficient prevention of dissemination and successful eradication of Erwinia amylovora (the cause of fire blight in Aragón, Spain

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    Ana PALACIO-BIELSA

    2013-01-01

    Full Text Available Erwinia amylovora was detected on pome fruits in the Aragón region (North-Eastern Spain, in a ca. 5 km radius area located in the mid Jalón river (mid Ebro Valley in the province of Zaragoza, during 2000‒2003. Eight years have now passed since this pathogen was last detected, without new infections being reported in the same area. The bases for surveys and rapid eradication performed have been analyzed in detail to understand the reasons for the success in removing fireblight. The results demonstrate that intensive surveillance, risk assessment, plant analyses using accurate identification methods, and, especially, rapid total or selective eradication of infected trees in the plots have been very effective in preventing the generalized spread of fireblight and in delaying economic losses associated with this disease. Eradication and compensation to growers, estimated to cost approx. € 467,000, were clearly counterbalanced by the economic value of apple and pear production in the 2000‒2003 period (approx. € 368 million. Fire blight risk-assessment, using the MARYBLYT system, showed that climatic conditions in the studied area were favourable to infections during the analyzed period (1997‒2006. Molecular characterization of E. amylovora strains had revealed their homogeneity, suggesting that these fire blight episodes could have been caused by just one inoculum source, supporting the hypothesis that there was a unique introduction of E. amylovora in the studied area. Spatial spread of E. amylovora to trees was analyzed within six orchards, indicating an aggregated distribution model. This Spanish experience demonstrates the success of scientifically-based prevention methods that lead to the deployment of a fast and strict containment strategy, useful for other Mediterranean areas.

  4. Same ammo, different weapons: enzymatic extracts from two apple genotypes with contrasted susceptibilities to fire blight (Erwinia amylovora) differentially convert phloridzin and phloretin in vitro.

    Science.gov (United States)

    Gaucher, Matthieu; Dugé de Bernonville, Thomas; Guyot, Sylvain; Dat, James F; Brisset, Marie-Noëlle

    2013-11-01

    The necrogenic bacterium Erwinia amylovora responsible for the fire blight disease causes cell death in apple tissues to enrich intercellular spaces with nutrients. Apple leaves contain large amounts of dihydrochalcones (DHCs), including phloridzin and its aglycone phloretin. Previous work showed an important decrease in the constitutive DHCs stock in infected leaves, probably caused by transformation reactions during the infection process. At least two flavonoid transformation pathways have been described so far: deglucosylation and oxidation. The aim of the present study was to determine whether DHCs are differentially converted in two apple genotypes displaying contrasted susceptibilities to the disease. Different analyses were performed: i) enzymatic activity assays in infected leaves, ii) identification/quantification of end-products obtained after in vitro enzymatic reactions with DHCs, iii) evaluation of the bactericidal activity of end-products. The results of the enzymatic assays showed that deglucosylation was dominant over oxidation in the susceptible genotype MM106 while the opposite was observed in the resistant genotype Evereste. These data were confirmed by LC-UV/Vis-MS analysis of in vitro reaction mixtures, especially because higher levels of o-quinoid oxidation products of phloretin were measured by using the enzymatic extracts of Evereste infected leaves. Their presence correlated well with a strong bactericidal activity of the reaction mixtures. Thus, our results suggest that a differential transformation of DHCs occur in apple genotypes with a potential involvement in the establishment of the susceptibility or the resistance to fire blight, through the release of glucose or of highly bactericidal compounds respectively. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  5. AraC/XylS family stress response regulators Rob, SoxS, PliA, and OpiA in the fire blight pathogen Erwinia amylovora.

    Science.gov (United States)

    Pletzer, Daniel; Schweizer, Gabriel; Weingart, Helge

    2014-09-01

    Transcriptional regulators of the AraC/XylS family have been associated with multidrug resistance, organic solvent tolerance, oxidative stress, and virulence in clinically relevant enterobacteria. In the present study, we identified four homologous AraC/XylS regulators, Rob, SoxS, PliA, and OpiA, from the fire blight pathogen Erwinia amylovora Ea1189. Previous studies have shown that the regulators MarA, Rob, and SoxS from Escherichia coli mediate multiple-antibiotic resistance, primarily by upregulating the AcrAB-TolC efflux system. However, none of the four AraC/XylS regulators from E. amylovora was able to induce a multidrug resistance phenotype in the plant pathogen. Overexpression of rob led to a 2-fold increased expression of the acrA gene. However, the rob-overexpressing strain showed increased resistance to only a limited number of antibiotics. Furthermore, Rob was able to induce tolerance to organic solvents in E. amylovora by mechanisms other than efflux. We demonstrated that SoxS from E. amylovora is involved in superoxide resistance. A soxS-deficient mutant of Ea1189 was not able to grow on agar plates supplemented with the superoxide-generating agent paraquat. Furthermore, expression of soxS was induced by redox cycling agents. We identified two novel members of the AraC/XylS family in E. amylovora. PliA was highly upregulated during the early infection phase in apple rootstock and immature pear fruits. Multiple compounds were able to induce the expression of pliA, including apple leaf extracts, phenolic compounds, redox cycling agents, heavy metals, and decanoate. OpiA was shown to play a role in the regulation of osmotic and alkaline pH stress responses. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  6. Functional implications of the beta-helical protein fold: differences in chemical and thermal stabilities of Erwinia chrysanthemi EC16 pectate lyases B, C, and E.

    Science.gov (United States)

    Hurlbert, J C; Preston, J F

    2000-09-15

    Colonization of plant tissue by the phytopathogen Erwinia chrysanthemi EC16 is aided by the activities of the pectate lyase isozymes (PLs), which depolymerize the polygalacturonic acid component (PGA) of plant cell walls. The bacterium secretes four pectate lyases (PLa, PLb, PLc, and PLe), two of which, PLc and PLe, have been shown to fold into a similar domain motif, the beta-helix. To understand the rationale behind the evolution and retention of these isoforms, the susceptibilities of pectate lyases B, C, and E to chemical and thermal denaturation and the resulting enzymatic inactivation were examined. With guanidine hydrochloride used as a denaturant, all three pectate lyases denatured with transition midpoint guanidine hydrochloride concentrations (Cm) of 1.3, 1.1, and 1.8 M for PLb, PLc, and PLe, respectively. Lyase activity decreased in direct response to loss of secondary structure in all enzymes. Pectate lyases B and C demonstrated increased enzymatic activity at temperatures above 30 degrees C, with maximal activity observed at 40 degrees C for PLb and 35 degrees C for PLc. Transition midpoints (Tm) as measured by circular dichroism were at 46.9 degrees C for PLb and 44.3 degrees C for PLc, indicating detectable conformational changes accompanying thermal inactivation. Decreased enzymatic activity of PLe was observed at all temperatures above 30 degrees C, and the enzyme was found to possess a Tm at 38.9 degrees C. The data demonstrate structural differences among these enzymes that may be the basis for different enzymatic efficiencies under the potential array of environmental conditions experienced by the bacterium. These differences, in turn, may play a part in the retention of these isozymes as virulence factors, allowing the successful colonization of susceptible plant hosts.

  7. INDUCCIÓN DE LA ACTIVIDAD DE LA ENZIMA FENILALANINA AMONIO LIASA EN CLAVEL (Dianthus caryophyllus L POR ELICITORES DEL HONGO Fusarium oxysporum f. sp. Dianthi raza 2

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    Harold Ardila

    2008-04-01

    Full Text Available Con el fin de evaluar el comportamiento a nivel del tallo de la enzima fenilalanina amonio liasa (PAL, por su nombre en inglés phenylalanine ammonia liase, durante la interacción clavel-Fusarium oxysporum f. sp. dianthi raza 2, se seleccionaron las condiciones para su extracción y cuantificación de la actividad. Para la extracción a partir de tallos y raíces se seleccionó un tratamiento previo del material vegetal con acetona y posterior extracción con buffer borato pH 8,8 con EDTA 2mMy -mercaptoetanol 18 mM. Para su cuantificación a nivel del tallo se debe realizar un ensayo discontinuo por 10 min, a 37 oC, pH 8,0 y a una concentración de sustrato de 35 mM. Adicionalmente se muestra mediante un ensayo in vivo el efecto que tiene, como inductor de esta enzima, la aplicación de un extracto crudo del patógeno. Los resultados observados indican que esta enzima se induce significativamente en tallos de claveles de la variedad tolerante “Kiss” durante el tratamiento por aspersión con el extracto crudo del patógeno, mientras que dicha inducción fue inexistente para la infección directamente con el patógeno. La inducción en esta variedad indica que en este extracto del patógeno se presentan elicitores potenciales para la inducción de esta enzima y por ende de la ruta fenilpropanoide.

  8. Piriformospora indica cell wall extract as the best elicitor for asiaticoside production in Centella asiatica (L.) Urban, evidenced by morphological, physiological and molecular analyses.

    Science.gov (United States)

    Jisha, S; Gouri, P R; Anith, K N; Sabu, K K

    2018-02-07

    Vascular plants synthesise a multitude of organic molecules or phytochemicals, referred to as "secondary metabolites". These molecules are involved in a variety of roles in the life span of plants, ranging from structural ones to protection. Centella asiatica (L.) Urban has probably been used since prehistoric times and has been reported to have been used for various medicinal and cosmetic purposes. The plant contains several active constituents, of which the most important is asiaticoside, a triterpenoid. Asiaticoside content in C. asiatica can be enhanced by the use of biotic elicitors like Piriformospora indica. P. indica has been used as a model to study the mechanisms and evolution of mutualistic symbiosis. P. indica is similar to Arbuscular Mycorrhizal (AM) fungi in terms of plant growth promotional effects. The autoclaved fraction from P. indica (PiCWE) was found to be the most active fraction in promoting the plant biomass and asiaticoside content. To date, there are no reports on the potential role of PiCWE in enhancement of asiaticoside over the control and P. indica colonized plants, which was evidenced by the differential expression of key genes involved and final asiaticoside content along with the determination of phytohormones. Moreover, differential expression of selected miRNAs in PiCWE - C. asiatica root interactions over the control and P. indica treated C. asiatica leaf samples was also scrutinized. The important consequence of induction with PiCWE was the significant enhancement of asiaticoside in the PiCWE induced plants in comparison with the asiaticoside content in control and P. indica-C. asiatica interaction. In addition, the role of miRNAs in C. asiatica - PiCWE would enable more in-depth studies for deciphering the molecular and physiological mechanisms of the association and regulation of PiCWE - C. asiatica interactions. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  9. A single amino acid mutation affects elicitor and expansins-like activities of cerato-platanin, a non-catalytic fungal protein.

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    Simone Luti

    Full Text Available Cerato-platanin (CP is a non-catalytic, cysteine-rich protein, the first member of the cerato-platanin family. It is a single-domain protein with a double Ψ/β barrel domain resembling the D1 domain of plant and bacterial expansins. Similarly to expansins, CP shows a cell wall-loosening activity on cellulose and can be defined as an expanisin-like protein, in spite of the missing D2 domain, normally present in plant expansins. The weakening activity shown on cellulose may facilitate the CP-host interaction, corroborating the role of CP in eliciting plant defence response. Indeed, CP is an elicitor of primary defences acting as a Pathogen-Associated Molecular Patterns (PAMP. So far, structure-function relationship study has been mainly performed on the bacterial BsEXLX1 expansin, probably due to difficulties in expressing plant expansins in heterologous systems. Here, we report a subcloning and purification method of CP in the engineered E. coli SHuffle cells, which proved to be suitable to obtain the properly folded and biologically active protein. The method also enabled the production of the mutant D77A, rationally designed to be inactive. The wild-type and the mutated CP were characterized for cellulose weakening activity and for PAMP activity (i.e. induction of Reactive Oxygen Species synthesis and phytoalexins production. Our analysis reveals that the carboxyl group of D77 is crucial for expansin-like and PAMP activities, thus permitting to establish a correlation between the ability to weaken cellulose and the capacity to induce defence responses in plants. Our results enable the structural and functional characterization of a mono-domain eukaryotic expansin and identify the essential role of a specific aspartic residue in cellulose weakening.

  10. Identification of the pepper SAR8.2 gene as a molecular marker for pathogen infection, abiotic elicitors and environmental stresses in Capsicum annuum.

    Science.gov (United States)

    Lee, Sung Chul; Hwang, Byung Kook

    2003-01-01

    Pepper ( Capsicum annuum L.) SAR8.2 genes, designated CASAR82A, B and C, which are induced by all the biotic and abiotic stresses, were isolated from a pepper cDNA library constructed with the mRNAs from pepper plants infected with Xanthomonas campestris pv. vesicatoria. The pepper CASAR82A, B and C gene products, which are very similar to each other in amino acid sequences, have 43-50% homology with those of tobacco SAR8.2 genes. The CASAR8.2 genes were not constitutively expressed in any of the organs of healthy pepper plants. In contrast, the CASAR82A gene was locally or systemically induced in pepper plants infected by X. campestris pv. vesicatoria, Colletotrichum coccodes or Phytophthora capsici. Strong induction of the CASAR82A gene also was found in pepper leaves treated with ethylene, methyl jasmonate, indole-3-acetic acid, abscisic acid, salicylic acid, benzothiadiazole, DL-beta- n-amino butyric acid or hydrogen peroxide. Interestingly, the transcription of the CASAR82A gene was rapidly triggered by high salinity, drought or low-temperature stresses, but not by mechanical wounding. In situ hybridization results revealed that the CASAR82A mRNAs were localized in phloem and epidermal cells of pepper leaf and stem tissues infected by C. coccodes and P. capsici, or treated with salicylic acid. These results thus suggest that pepper SAR8.2 genes may be valuable as a molecular marker for the detection of various pathogen infections, abiotic elicitors and environmental stresses.

  11. SoxR-dependent response to oxidative stress and virulence of Erwinia chrysanthemi: the key role of SufC, an orphan ABC ATPase.

    Science.gov (United States)

    Nachin, L; El Hassouni, M; Loiseau, L; Expert, D; Barras, F

    2001-02-01

    Erwinia chrysanthemi causes soft-rot disease in a great variety of plants. In addition to the depolymerizing activity of plant cell wall-degrading enzymes, iron acquisition and resistance to oxidative stress contribute greatly to the virulence of this pathogen. Here, we studied the pin10 locus originally thought to encode new virulence factors. The sequence analysis revealed six open reading frames that were homologous to the Escherichia coli sufA, sufB, sufC, sufD, sufS and sufE genes. Sequence similarity searching predicted that (i) SufA, SufB, SufD, SufS and SufE proteins are involved in iron metabolism and possibly in Fe-S cluster assembly; and (ii) SufC is an ATPase of an ABC transporter. The reverse transcription-polymerase chain reaction procedure showed that the sufABCDSE genes constitute an operon. Expression of a sufB:uidA fusion was found to be induced in iron-deficient growth conditions and to be repressed by the iron-sensing Fur repressor. Each of the six suf genes was inactivated by the insertion of a cassette generating a non-polar mutation. The intracellular iron level in the sufA, sufB, sufC, sufS and sufE mutants was higher than in the wild type, as assessed by increased sensitivity to the iron-activated antibiotic streptonigrin. In addition, inactivation of sufC and sufD led to increased sensitivity to paraquat. Virulence tests showed that sufA and sufC mutants exhibited reduced ability to cause maceration of chicory leaves, whereas a functional sufC gene was necessary for the bacteria to cause systemic invasion of Saintpaulia ionantha. The E. coli sufC homologue was inactivated by reverse genetic. This mutation was found to modify the soxR-dependent induction of soxS gene expression. We discuss the possibility that SufC is a versatile ATPase that can associate either with the other Suf proteins to form a Fe-S cluster-assembling machinery or with membrane proteins encoded elsewhere in the chromosome to form an Fe-S ABC exporter. Overall, these

  12. Functional regions of HpaXm as elicitors with specific heat tolerance induce the hypersensitive response or plant growth promotion in nonhost plants.

    Science.gov (United States)

    Liu, Yue; Zhou, Xiaoyun; Liu, Wenbo; Xiong, Xiaohui; Lv, Chuyang; Zhou, Xiang; Miao, Weiguo

    2018-01-01

    HpaXm produced by the cotton leaf blight bacterium Xanthomonas citri subsp. malvacearum is a novel harpin elicitor of the induced hypersensitive response (HR) in tobacco. We investigated whether fragments of HpaXm, compared with fragments of Hpa1Xoo, are sufficient for HR or plant growth promotion (PGP) elicitation using four synthetic peptides (HpaXm35-51, HpaXm10-39, Hpa1Xoo36-52 and Hpa1Xoo10-40). We also heated the fragments to determine the heat tolerance of the functional fragments. HpaXm35-51 and Hpa1Xoo36-52 induced hypersensitive response (HR). Bursts of reactive oxygen intermediates (ROI) induced by HpaXm35-51 and Hpa1Xoo36-52 were earlier and stronger than those induced by HpaXm and Hpa1Xoo. In plants treated with HpaXm35-51 or Hpa1Xoo36-52, the expression of the HR marker genes Hin1 and Hsr203J and the active oxygen metabolism related gene AOX were significantly upregulated. These findings suggest that the predicted α-helical structures of the HpaXm35-51 and Hpa1Xoo36-52 fragments are crucial for HR. PGP result by soaking seeds in unheated/heated HpaXm10-39 or Hpa1Xoo10-40 solution prior to transfer, which obviously enhances root growth and the aerial parts of plants. The PGP related gene NtEXP6 was greatly enhanced when plants were sprayed with a solution of HpaXm10-39 or Hpa1Xoo10-40; heated fragment treatments induced higher levels of NtEXP6 expression than unheated HpaXm fragments. In addition, HR marker genes induced by the heated fragments had lower expression levels than when induced with unheated HpaXm fragments. Moreover, the expression levels of HR marker genes and PGP related genes induced by treatment with Hpa1Xoo fragments before or after heating were the opposite of those induced by HpaXm fragments. Different functional fragments of harpin and different harpins with the same functional region have different degrees of heat tolerance. Therefore, the heat resistance of harpin is conservative, but the degree of heat tolerance of the

  13. fektivitas Penambahan Elisitor Asam Jasmonik dalam Peningkatan Sintesis Senyawa Bioaktif Andrografolid pada Kultur Suspensi Sel Sambiloto (Effectiveness of Jasmonic Acid Elicitor Addition for Andrographolide Synthesis Induction of Sambiloto Culture

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    Noor Aini Habibah

    2009-03-01

    Full Text Available In this research, we have studied synthesis of improvement of andrographolid bioactive compound on cell culture of sambiloto by addition of jasmonic acid. The essential problems in this research are firstly, the effects of addition of jasmonic acid either can induce or not andrographolide synthesis improvement of cell culture of sambiloto and secondly, to observe the largest content of andrographolide in jasmonic acid concentrations. Meanwhile, the purpose of this research are to observe the functions of jasmonic acid elicitor for induction of andrographolide synthesis improvement of cell culture of sambiloto and to optimize jasmonic acid concentrations which can produce the largest andrographolide content. The independent variable is concentration of addition of jasmonic acid on cell culture and the dependent variable are the growth of cell suspension culture and andrographolide bioactive content. Experiment result show that the optimum medium of sambiloto cell consist of Murashige & Skoog (1962 medium supplemented by 0,5 ppm kinetin and 2,4-D 5 ppm. The cell growth phases are the followings : lag phase at age of 0-5 days, exponential phase of 5-15 days, and stationary phase at age of longer than 15 days. The highest andrographolide was 4,66 x 10-2 reached in cell culture was supplemented with 10 µM jasmonic acid. Keywords : andrographolide, sambiloto cell suspension culture, jasmonic acid elicitor.

  14. Indução de resistência do mamoeiro à podridão radicular por indutores bióticos e abióticos Resistance induction to root rot in papaya by biotic and abiotic elicitors

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    Giltembergue Macedo Tavares

    2009-11-01

    Full Text Available O objetivo deste trabalho foi avaliar o potencial do uso de indutores de resistência bióticos e abióticos na redução da podridão radicular em mamoeiro. Mudas de mamoeiro foram pulverizadas com os fungicidas fosetil-Al, metalaxil e Mancozeb (2 g L-1, com os indutores abióticos fosfito de potássio (2,5 e 5 mL L-1, ácido salicílico 0,15 e 0,30%, Reforce (indutor comercial + ácido salicílico a 5%, acibenzolar-S-metil (ASM (0,15 e 0,30 g L-1, e com o indutor biótico Saccharomyces cerevisiae (3 e 6 mL L-1, três e seis dias antes da pulverização de 1 mL de suspensão de 10(5 zoósporos mL-1 de Phytophthora palmivora. Todos os tratamentos tiveram efeito no controle da podridão de raízes em relação à testemunha, com exceção do Reforce + ácido salicílico a 5% (3 mL L-1, seis dias antes da inoculação. Os tratamentos com ASM, com exceção da dosagem 0,15 g L-1 seis dias antes da inoculação, apresentaram resultados similares aos dos fungicidas metalaxil e Mancozeb. Plantas pulverizadas com ASM apresentaram aumento de atividade da peroxidase e beta-1,3-glucanase e maior concentração de lignina que a testemunha. No entanto, esses tratamentos não tiverem efeito sobre a atividade da quitinase. O ASM é um potencial indutor de resistência a P. palmivora em mamoeiro.The objective of this work was to evaluate the potential use of biotic and abiotic elicitors of resistance in the reduction of root rot in papaya. Papaya seedlings were sprayed with the fosetil-Al and metalaxyl and Mancozeb (2 g L-1 fungicides, with the potassium phosphite (2.5 and 5 mL L-1, salicylic acid 0.15 e 0.30%, Reforce (commercial product + salicylic acid 5%, acibenzolar-S-methyl (ASM (0.15 and 0.30 g L-1 abiotic elicitors, and with the Saccharomyces cerevisiae (3 and 6 mL L-1 biotic elicitor, applied three and six days before the inoculation with 1 mL of 10(5 zoospores mL-1 suspension of Phytophthora palmivora. All treatments were effective in controlling

  15. Reference: 490 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available tration. The heterologous expression in yeast was utilized to verify that the AtP...TR3 protein transports di-and tripeptides. The T-DNA insert in the Atptr3-1 mutant in the Arabidopsis ecotype C24 re...tr3-2 mutant of the Col-0 ecotype. The AtPTR3 expression was shown to be regulated by several signalling com...d in the SA and JA signalling mutants. The Atptr3 mutant plants had increased susceptibility to virulent pat...hogenic bacteria Erwinia carotovora subsp. carotovora and Pseudomonas syringae pv. tomato, and produced more re

  16. Direct detection of the plant pathogens Burkholderia glumae, Burkholderia gladioli pv. gladioli, and Erwinia chrysanthemi pv. zeae in infected rice seedlings using matrix assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Kajiwara, Hideyuki

    2016-01-01

    The plant pathogens Burkholderia glumae, Burkholderia gladioli pv. gladioli, and Erwinia chrysanthemi pv. zeae were directly detected in extracts from infected rice seedlings by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This method did not require culturing of the pathogens on artificial medium. In the MALDI-TOF MS analysis, peaks originating from bacteria were found in extracts from infected rice seedlings. The spectral peaks showed significantly high scores, in spite of minor differences in spectra. The spectral peaks originating from host plant tissues did not affect this direct MALDI-TOF MS analysis for the rapid identification of plant pathogens. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Erwinia: rot voor de bollenteler

    NARCIS (Netherlands)

    Doorn, van J.; Vreeburg, P.J.M.; Leeuwen, van P.J.; Dees, R.H.L.; Martin, W.S.

    2009-01-01

    De afgelopen acht jaar ondervonden bloembolgewassen zoals hyacint, Muscari, dahlia en iris in toenemende mate problemen met zachtrot : agressief snot zoals de gedupeerde telers deze bacterieziekte noemden. Agressief rot heeft geleid tot grote teeltkundige problemen en economische schade. De

  18. Estudio por HPLC de la acción de dos elicitores bióticos sobre la producción in vitro de metabolitos secundarios en células de clavel (Dianthus canophyilus L

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    Blanca Ligia Higuera M.

    2010-09-01

    Full Text Available Como parte de la investigación que busca contribuir al estudio de los mecanismos de defensa que operan en la interacción clavel (Dianthus caryophyllus L. - Fusarium oxysporum f. sp. dianthi, se evaluó la producción in vitro de metabolitos secundarios asociados con resistencia del clavel. Para ello se usaron cultivos de células en suspensión de variedades de clavel resistente (var. Candy y susceptible (var. Rosana, elicitadas durante 3 y 15 días con dos elicitores bióticos, ácido fusárico y filtrado de medio de cultivo del hongo.

  19. Tissue-specific gene-expression patterns of genes associated with thymol/carvacrol biosynthesis in thyme (Thymus vulgaris L.) and their differential changes upon treatment with abiotic elicitors.

    Science.gov (United States)

    Majdi, Mohammad; Malekzadeh-Mashhady, Atefe; Maroufi, Asad; Crocoll, Christoph

    2017-06-01

    Thyme (Thymus vulgaris L.) is known to produce a variety of phenolic monoterpenes such as thymol and carvacrol. Thymol and carvacrol are health-promoting, biocide and antitoxin compounds and have been considered as the main constituents of essential oils in T. vulgaris. To improve our understanding of the regulation of monoterpene biosynthesis in thyme, the expression of genes related to thymol and carvacrol biosynthesis in different tissues and in response to abiotic elicitors was analyzed. Methyl jasmonate (MeJA), salicylic acid (SA), trans-cinnamic acid (tCA) and UV-C irradiation were applied to T. vulgare leaves and transcript levels of early (DXR) and late (TvTPS1, CYP71D178 and CYP71D180) biosynthetic genes of thymol and carvacrol were measured. The results showed that early step and late step genes in thymol/carvacrol biosynthesis are differentially regulated. DXR was not found to be exclusively expressed in glandular trichomes; in contrast, biosynthetic genes including γ-terpinene synthase (TvTPS1) and two cytochrome P450s, CYP71D178 and CYP71D180, were preferentially expressed in glandular secretory trichomes. The high expression of late biosynthetic genes in glandular trichomes, which also contain the highest concentration of thymol and carvacrol, suggests that glandular trichomes are the structure in which thymol/carvacrol biosynthesis and accumulation occur. Our results indicate that in addition to abiotic elicitors, developmental and spatial factors also play a key role in the biosynthesis of thymol and carvacrol, most likely relating to glandular trichome density and/or activity. Hence optimization of these factors could be considered as a useful strategy to achieve high yield of valuable compounds in T. vulgare or other closely related plant species. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. Plasma asparaginase activity, asparagine concentration, and toxicity after administration of Erwinia asparaginase in children and young adults with acute lymphoblastic leukemia: Phase I/II clinical trial in Japan.

    Science.gov (United States)

    Ogawa, Chitose; Taguchi, Fumi; Goto, Hiroaki; Koh, Katsuyoshi; Tomizawa, Daisuke; Ohara, Akira; Manabe, Atsushi

    2017-09-01

    A phase I/II study of Erwinia asparaginase in Japanese children and young adults with acute lymphoblastic leukemia (ALL) was performed to investigate its activity and toxicity. Eligible patients were in remission and had developed allergy to Escherichia coli asparaginase. Erwina asparaginase was intramuscularly administrated on days 2, 5, 7, 9, 11, and 13. To measure the plasma l-asparagine concentration (PAC), amino acids were derivatized with Nα -(5-fluoro-2,4-dinitrophenyl)-l-leucinamide. Six consecutive patients completed the phase I study with 25,000 IU/m2 per dose without dose-limiting toxicity and 18 patients completed the phase II study with 25,000 IU/m2 per dose. Median age of 24 patients was 7.5 (range 2-16) years. The half-life of plasma asparaginase activity (PAA) was 16.9 ± 7.5 hr and the maximum PAA was 3.10 ± 1.47 IU/ml (n = 23, noncompartment model). PAA of 0.1 IU/ml or more was achieved in all 23 patients (100%) 48 hr and in 18 of 23 patients (78.3%) 72 hr after the first administration. During the 2-week study, 94.2% (65 of 69) of the 48-hr samples and 80.4% (37 of 46) of the 72-hr samples had PAA of 0.1 IU/ml or more. PAC less than 1.0 μM was achieved in 95.7% patients 48 and 72 hr after administration. PAC values in all the samples were greater than the limit of quantitation (0.0625 μM). Karnofsky performance status of all patients was good during the 2-week study. Erwinia asparaginase 25,000 IU/m2 per dose × six intramuscular administrations in 2 weeks was well tolerated, pharmacologically efficacious, and safe in Japanese patients with ALL/lymphoblastic lymphoma. © 2017 Wiley Periodicals, Inc.

  1. Selective inhibition of jasmonic acid accumulation by a small α, β-unsaturated carbonyl and phenidone reveals different modes of octadecanoid signalling activation in response to insect elicitors and green leaf volatiles in Zea mays

    Science.gov (United States)

    2011-01-01

    Background Plants often release a complex blend of volatile organic compounds (VOC) in response to insect herbivore damage. Among those blends of VOC green leaf volatiles (GLV) have been demonstrated to function as defence signals between plants, thereby providing protection against impending herbivory. A problem in understanding the mode of action of these 6-carbon aldehydes, alcohols, and esters is caused by their structural diversity. Besides different degrees of oxidation, E-2- as well as Z-3-configured isomers are often released. This study was therefore initiated to determine the structural requirement necessary to exhibit biological activity measured as jasmonic acid (JA) accumulation in Zea mays seedlings. Findings The structure/function analysis of green leaf volatiles and related compounds revealed that an olefinic bond in position 2 or 3 and a size of 6-8 carbons is required for biological activity in maize. Also, it was found that the presence of an α, β-unsaturated carbonyl is not a prerequisite for activity. However, by treating plants first with volatile acrolein it was discovered that this smallest α, β-unsaturated carbonyl inhibits JA accumulation in response to insect elicitor treatment, but not after GLV exposure. This selective inhibitory effect was also found for phenidone, an inhibitor of lipoxygenases. These findings led to the discovery of a pool of protein-associated 12-oxo-phytodienoic acid, a biosynthetic precursor of JA, which appeared to be rapidly converted into JA upon exposure to GLV. Conclusions The structure/function analysis of GLV demonstrates a high degree of correlation between the compounds released by wounded plants in nature and their biological activity. The selective inhibitory effects of acrolein and phenidone on insect elicitor- and GLV-induced JA accumulation in maize led to the discovery of a pool of protein-associated precursor, which is rapidly activated and transformed to JA after exposure to GLV. This novel

  2. Co-regulation of polysaccharide production, motility, and expression of type III secretion genes by EnvZ/OmpR and GrrS/GrrA systems in Erwinia amylovora.

    Science.gov (United States)

    Li, Wenting; Ancona, Veronica; Zhao, Youfu

    2014-02-01

    The EnvZ/OmpR and GrrS/GrrA systems, two widely distributed two-component systems in gamma-Proteobacteria, negatively control amylovoran biosynthesis in Erwinia amylovora, and the two systems regulate motility in an opposing manner. In this study, we examined the interplay of EnvZ/OmpR and GrrS/GrrA systems in controlling various virulence traits in E. amylovora. Results showed that amylovoran production was significantly higher when both systems were inactivated, indicating that the two systems act as negative regulators and their combined effect on amylovoran production appears to be enhanced. In contrast, reduced motility was observed when both systems were deleted as compared to that of grrA/grrS mutants and WT strain, indicating that the two systems antagonistically regulate motility in E. amylovora. In addition, glycogen accumulation was much higher in envZ/ompR and two triple mutants than that of grrS/grrA mutants and WT strain, suggesting that EnvZ/OmpR plays a dominant role in regulating glycogen accumulation, whereas levan production was significantly lower in the grrS/grrA and two triple mutants as compared with that of WT and envZ/ompR mutants, indicating that GrrS/GrrA system dominantly controls levan production. Furthermore, both systems negatively regulated expression of three type III secretion (T3SS) genes and their combined negative effect on hrp-T3SS gene expression increased when both systems were deleted. These results demonstrated that EnvZ/OmpR and GrrS/GrrA systems co-regulate various virulence factors in E. amylovora by still unknown mechanisms or through different target genes, sRNAs, or proteins, indicating that a complex regulatory network may be involved, which needs to be further explored.

  3. The expression of the hydroxyproline-rich glycopeptide systemin precursor A in response to (a)biotic stress and elicitors is indicative of its role in the regulation of the wound response in tobacco (Nicotiana tabacum L.).

    Science.gov (United States)

    Rocha-Granados, Carmen del María; Sánchez-Hernández, Carlos; Sánchez-Hernández, Carla; Martínez-Gallardo, Norma Angélica; Ochoa-Alejo, Neftalí; Délano-Frier, John Paul

    2005-11-01

    Two hydroxyproline-rich glycopeptide systemin (TobHS) precursor proteins known as preproTobHypSys-A and B were recently discovered in tobacco (Nicotiana tabacum L.) [Pearce et al. in Nature 411:817-820, 2001]. In this work, the effect of elicitors, insect damage, and abiotic stress on the expression of preproTobHypSys-A ppTobHS-A) in tobacco plants was evaluated. Foliar application of methyl jasmonate preferentially induced the systemic expression of ppTobHS-A in leaves phyllotactically one position above-treated leaves. Abscisic acid strongly induced ppTobHS-A, but water-stress did not. Mechanical wound-induction of ppTobHS-A in young plantlets was rapidly (1 h) and simultaneously detected in wounded and upper unwounded leaves, whereas in older plants induction was slow (12 h) and localized. ppTobHS-A was induced in plants infested with Bemisia tabaci or damaged by herbivory with Manduca sexta larvae. Compared to mechanical wounding, larval herbivory induced a stronger and more stable expression of ppTobHS-A. Moreover, exposure to Manduca-damaged plants induced its expression in neighboring intact plants. In most treatments, the expression patterns of ppTobHS-A coincided with those of selected wound-responsive (WR) genes (e.g., PIOX, NtPI-I, TPI). This correlation was tighter in the wounded and MeJA-treated leaves, whereas in distal, undamaged leaves, it appeared to depend on the type of WR gene examined and on the type of damage sustained by the plant. These results are consistent with the perceived role of the TobHS in defense signaling.

  4. The natural plant stress elicitor cis-jasmone causes cultivar-dependent reduction in growth of the stink bug, Euschistus heros and associated changes in flavonoid concentrations in soybean, Glycine max.

    Science.gov (United States)

    da Graça, José P; Ueda, Tatiana E; Janegitz, Tatiani; Vieira, Simone S; Salvador, Mariana C; de Oliveira, Maria C N; Zingaretti, Sonia M; Powers, Stephen J; Pickett, John A; Birkett, Michael A; Hoffmann-Campo, Clara B

    2016-11-01

    To test the hypothesis that the plant stress related elicitor cis-jasmone (cJ) provides protection in soybean pods against the seed-sucking stink bug pest, Euschistus heros, the growth of E. heros on cJ-treated pods was investigated using three soybean cultivars differing in insect susceptibility, i.e. BRS 134 (susceptible), IAC 100 (resistant) and Dowling (resistant). E. heros showed reduced weight gain when fed cJ-treated Dowling, whereas no effect on weight gain was observed when fed other treated cultivars. Using analysis of variance, a three factor (cultivar x treatment x time) interaction was observed with concentrations of the flavonoid glycosides daidzin and genistin, and their corresponding aglycones, daidzein and genistein. There were increases in genistein and genistin concentrations in cJ-treated Dowling at 144 and 120 h post treatment, respectively. Higher concentrations of malonyldaidzin and malonylgenistin in Dowling, compared to BRS 134 and IAC 100, were observed independently of time, the highest concentrations being observed in cJ-treated seeds. Levels of glycitin and malonylglycitin were higher in BRS 134 and IAC 100 compared to Dowling. Canonical variate analysis indicated daidzein (in the first two canonical variates) and genistein (in the first only) as important discriminatory variables. These results suggest that cJ treatment leads to an increase in the levels of potentially defensive isoflavonoids in immature soybean seeds, but the negative effect upon E. heros performance is cultivar-dependent. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. Nicotinic acid and nicotinamide on pear and apple flowers are not limiting factors for Erwinia amylovora growth when these chemicals are considered in relation to cultivar and flower age

    Directory of Open Access Journals (Sweden)

    Thomas PATERNOSTER

    2011-05-01

    Full Text Available Normal 0 14 false false false IT ZH-TW X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabella normale"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Fire blight, caused by Erwinia amylovora, is a devastating disease of pear (Pyrus communis and apple (Malus × domestica in many areas of the world. The disease is often initiated by epiphytic populations that multiply on flowers and colonize the hypanthia. In vitro, E. amylovora requires nicotinic acid (NicAc and/or nicotinamide (NicNH2 as essential growth factors. The amount of NicAc on pear hypanthia was positively correlated with the altitude of the growing site and was inversely correlated with the sum of the maximum temperatures in the 30 days before flowering. The sum of the amounts of NicAc and NicNH2 on the hypanthia was about 6 to 23 times higher in pear, and about 1.2 to 3.5 times higher in apple, than the amounts of NicAc or NicNH2 necessary to support maximum E. amylovora growth  in vitro. No correlation was found between the amounts of NicAc and NicNH2 on the hypanthia of different pear and apple cultivars and at different growth stages and the growth of E. amylovora after experimental inoculation. In conclusion, NicAc and NicNH2 are essential for E. amylovora growth but the amounts of these chemicals on pear and apple flowers do not limit the establishment of the pathogen when competing bacteria

  6. Nucleotide sequences of the arb genes, which control beta-glucoside utilization in Erwinia chrysanthemi: comparison with the Escherichia coli bgl operon and evidence for a new beta-glycohydrolase family including enzymes from eubacteria, archeabacteria, and humans.

    Science.gov (United States)

    el Hassouni, M; Henrissat, B; Chippaux, M; Barras, F

    1992-01-01

    The phytopathogenic bacterium Erwinia chrysanthemi, unlike other members of the family Enterobacteriaceae, is able to metabolize the beta-glucosides, arbutin, and salicin. A previous genetic analysis of the E. chrysanthemi arb genes, which mediate beta-glucoside metabolism, suggested that they were homologous to the Escherichia coli K-12 bgl genes. We have now determined the nucleotide sequence of a 5,065-bp DNA fragment containing three genes, arbG, arbF, and arbB. Deletion analysis, expression in minicell systems, and comparison with sequences of other proteins suggest that arbF and arbB encode a beta-glucoside-specific phosphotransferase system-dependent permease and a phospho-beta-glucosidase, respectively. The ArbF amino acid sequence shares 55% identity with that of the E. coli BglF permease and contains most residues thought to be important for a phosphotransferase. One change, however, was noted, since BglF Arg-625, presumably involved in phosphoryl transfer, was replaced by a Cys residue in ArbF. An analysis of the ArbB sequence led to the definition of a protein family which contained enzymes classified as phospho-beta-glucosidases, phospho-beta-galactosidases, beta-glucosidases, and beta-galactosidases and originating from gram-positive and gram-negative bacteria, archebacteria, and mammals, including humans. An analysis of this family allowed us (i) to speculate on the ways that these enzymes evolved, (ii) to identify a glutamate residue likely to be a key amino acid in the catalytic activity of each protein, and (iii) to predict that domain II of the human lactate-phlorizin hydrolase, which is involved in lactose intolerance, is catalytically nonactive. A comparison between the untranslated regions of the E. chrysanthemi arb cluster and the E. coli bgl operon revealed the conservation of two regions which, in the latter, are known to terminate transcription under noninducing conditions and be the target of the BglG transcriptional antiterminator under

  7. Tropospheric ozone as a fungal elicitor

    Indian Academy of Sciences (India)

    Prakash

    Salicylic acid (SA) plays a central role in the signal transmission for induction of SAR; in several species, a correlation has been demonstrated between concentration of SA and increased resistance to biotic stresses (Mur et al. 1996; Mauch-Mani and Métrauxs 1998; Mètrauxs 2001). SA is produced in the infected tissues ...

  8. Interacciones entre "Pythium ultimum" y bacterias de la rizosfera en la patogénesis de la podredumbre del tallo del brócoli

    OpenAIRE

    Parra Sáez, María Angeles

    2015-01-01

    sintomatología que se asocia comúnmente a la enfermedad denominada podredumbre blanda bacteriana ocasionada por la bacteria Erwinia carotovora. Sin embargo, en este trabajo se ha aislado al hongo Pythium ultimum creciendo, al mismo tiempo, con varias especies de bacterias que habitan corrientemente en los suelos del interior del tallo floral de piezas de brócoli maduras afectadas de podredumbre blanda en cultivos del sureste de España durante el año 2012. P. ultimum causa “damping-off” en num...

  9. Virulent bacterial infection improves aversive learning performance in Drosophila melanogaster.

    Science.gov (United States)

    Babin, Aurélie; Kolly, Sylvain; Kawecki, Tadeusz J

    2014-10-01

    Virulent infections are expected to impair learning ability, either as a direct consequence of stressed physiological state or as an adaptive response that minimizes diversion of energy from immune defense. This prediction has been well supported for mammals and bees. Here, we report an opposite result in Drosophila melanogaster. Using an odor-mechanical shock conditioning paradigm, we found that intestinal infection with bacterial pathogens Pseudomonas entomophila or Erwinia c. carotovora improved flies' learning performance after a 1h retention interval. Infection with P. entomophila (but not E. c. carotovora) also improved learning performance after 5 min retention. No effect on learning performance was detected for intestinal infections with an avirulent GacA mutant of P. entomophila or for virulent systemic (hemocoel) infection with E. c. carotovora. Assays of unconditioned responses to odorants and shock do not support a major role for changes in general responsiveness to stimuli in explaining the changes in learning performance, although differences in their specific salience for learning cannot be excluded. Our results demonstrate that the effects of pathogens on learning performance in insects are less predictable than suggested by previous studies, and support the notion that immune stress can sometimes boost cognitive abilities. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Bacterial Diseases of Bananas and Enset: Current State of Knowledge and Integrated Approaches Toward Sustainable Management

    Directory of Open Access Journals (Sweden)

    Guy Blomme

    2017-07-01

    Full Text Available Bacterial diseases of bananas and enset have not received, until recently, an equal amount of attention compared to other major threats to banana production such as the fungal diseases black leaf streak (Mycosphaerella fijiensis and Fusarium wilt (Fusarium oxysporum f. sp. cubense. However, bacteria cause significant impacts on bananas globally and management practices are not always well known or adopted by farmers. Bacterial diseases in bananas and enset can be divided into three groups: (1 Ralstonia-associated diseases (Moko/Bugtok disease caused by Ralstonia solanacearum and banana blood disease caused by R. syzygii subsp. celebesensis; (2 Xanthomonas wilt of banana and enset, caused by Xanthomonas campestris pv. musacearum and (3 Erwinia-associated diseases (bacterial head rot or tip-over disease Erwinia carotovora ssp. carotovora and E. chrysanthemi, bacterial rhizome and pseudostem wet rot (Dickeya paradisiaca formerly E. chrysanthemi pv. paradisiaca. Other bacterial diseases of less widespread importance include: bacterial wilt of abaca, Javanese vascular wilt and bacterial fingertip rot (probably caused by Ralstonia spp., unconfirmed. This review describes global distribution, symptoms, pathogenic diversity, epidemiology and the state of the art for sustainable disease management of the major bacterial wilts currently affecting banana and enset.

  11. Bacterial Diseases of Bananas and Enset: Current State of Knowledge and Integrated Approaches Toward Sustainable Management.

    Science.gov (United States)

    Blomme, Guy; Dita, Miguel; Jacobsen, Kim Sarah; Pérez Vicente, Luis; Molina, Agustin; Ocimati, Walter; Poussier, Stephane; Prior, Philippe

    2017-01-01

    Bacterial diseases of bananas and enset have not received, until recently, an equal amount of attention compared to other major threats to banana production such as the fungal diseases black leaf streak (Mycosphaerella fijiensis) and Fusarium wilt (Fusarium oxysporum f. sp. cubense). However, bacteria cause significant impacts on bananas globally and management practices are not always well known or adopted by farmers. Bacterial diseases in bananas and enset can be divided into three groups: (1) Ralstonia-associated diseases (Moko/Bugtok disease caused by Ralstonia solanacearum and banana blood disease caused by R. syzygii subsp. celebesensis); (2) Xanthomonas wilt of banana and enset, caused by Xanthomonas campestris pv. musacearum and (3) Erwinia-associated diseases (bacterial head rot or tip-over disease Erwinia carotovora ssp. carotovora and E. chrysanthemi), bacterial rhizome and pseudostem wet rot (Dickeya paradisiaca formerly E. chrysanthemi pv. paradisiaca). Other bacterial diseases of less widespread importance include: bacterial wilt of abaca, Javanese vascular wilt and bacterial fingertip rot (probably caused by Ralstonia spp., unconfirmed). This review describes global distribution, symptoms, pathogenic diversity, epidemiology and the state of the art for sustainable disease management of the major bacterial wilts currently affecting banana and enset.

  12. [Expression of cecropin P1 gene increases resistance of Camelina sativa (L.) plants to microbial phytopathogenes].

    Science.gov (United States)

    Zakharchenko, N S; Kaliaeva, M A; Bur'ianov, Ia I

    2013-05-01

    Transgenic plants of camelina (Camelina sativa (L.) Crantz) with the synthetic gene of antimicrobial peptide cecropin P1 (cecP1) were obtained. Agrobacterium-mediated transformation is performed using the binary vector pGA482::cecP1 by vacuum infiltration of flower buds. The presence of the cecP1 gene in the genome of plants was confirmed by PCR. cecP1 gene expression in transgenic plants was shown by Western blot analysis and by antimicrobial activity of plant extracts against the bacterial phytopathogene Erwinia carotovora. The plants of F0 and F1 generations had the normal phenotype and retained the ability to form viable seeds in self-pollination. cecP1 plants exhibit enhanced resistance to bacterial and fungal phytopathogens: Erwinia carotovora and Fusarium sporotrichioides. The increased sustainability of cecropin P1-expressing plants against salt stress is shown. The possibility of the integration of the cecP1 gene into the overall protective system of plants against biotic and abiotic stresses is discussed.

  13. Bacterial Diseases of Bananas and Enset: Current State of Knowledge and Integrated Approaches Toward Sustainable Management

    Science.gov (United States)

    Blomme, Guy; Dita, Miguel; Jacobsen, Kim Sarah; Pérez Vicente, Luis; Molina, Agustin; Ocimati, Walter; Poussier, Stephane; Prior, Philippe

    2017-01-01

    Bacterial diseases of bananas and enset have not received, until recently, an equal amount of attention compared to other major threats to banana production such as the fungal diseases black leaf streak (Mycosphaerella fijiensis) and Fusarium wilt (Fusarium oxysporum f. sp. cubense). However, bacteria cause significant impacts on bananas globally and management practices are not always well known or adopted by farmers. Bacterial diseases in bananas and enset can be divided into three groups: (1) Ralstonia-associated diseases (Moko/Bugtok disease caused by Ralstonia solanacearum and banana blood disease caused by R. syzygii subsp. celebesensis); (2) Xanthomonas wilt of banana and enset, caused by Xanthomonas campestris pv. musacearum and (3) Erwinia-associated diseases (bacterial head rot or tip-over disease Erwinia carotovora ssp. carotovora and E. chrysanthemi), bacterial rhizome and pseudostem wet rot (Dickeya paradisiaca formerly E. chrysanthemi pv. paradisiaca). Other bacterial diseases of less widespread importance include: bacterial wilt of abaca, Javanese vascular wilt and bacterial fingertip rot (probably caused by Ralstonia spp., unconfirmed). This review describes global distribution, symptoms, pathogenic diversity, epidemiology and the state of the art for sustainable disease management of the major bacterial wilts currently affecting banana and enset. PMID:28785275

  14. Synthesis and quantitative structure activity relationship (QSAR) of arylidene (benzimidazol-1-yl)acetohydrazones as potential antibacterial agents.

    Science.gov (United States)

    El-Kilany, Yeldez; Nahas, Nariman M; Al-Ghamdi, Mariam A; Badawy, Mohamed E I; El Ashry, El Sayed H

    2015-01-01

    Ethyl (benzimidazol-1-yl)acetate was subjected to hydrazinolysis with hydrazine hydrate to give (benzimidazol-1-yl)acetohydrazide. The latter was reacted with various aromatic aldehydes to give the respective arylidene (1H-benzimidazol-1-yl)acetohydrazones. Solutions of the prepared hydrazones were found to contain two geometric isomers. Similarly (2-methyl-benzimidazol-1-yl)acetohydrazide was reacted with various aldehydes to give the corresponding hydrazones. The antibacterial activity was evaluated in vitro by minimum inhibitory concentration (MIC) against Agrobacterium tumefaciens (A. tumefaciens), Erwinia carotovora (E. carotovora), Corynebacterium fascians (C. fascians) and Pseudomonas solanacearum (P. solanacearum). MIC result demonstrated that salicylaldehyde(1H-benzimidazol-1-yl)acetohydrazone (4) was the most active compound (MIC = 20, 35, 25 and 30 mg/L against A. tumefaciens, C. fascians, E. carotovora and P. solanacearum, respectively). Quantitative structure activity relationship (QSAR) investigation using Hansch analysis was applied to find out the correlation between antibacterial activity and physicochemical properties. Various physicochemical descriptors and experimentally determined MIC values for different microorganisms were used as independent and dependent variables, respectively. pMICs of the compounds exhibited good correlation (r = 0.983, 0.914, 0.960 and 0.958 for A. tumefaciens, C. fascians, E. carotovora and P. solanacearum, respectively) with the prediction made by the model. QSAR study revealed that the hydrophobic parameter (ClogP), the aqueous solubility (LogS), calculated molar refractivity, topological polar surface area and hydrogen bond acceptor were found to have overall significant correlation with antibacterial activity. The statistical results of training set, correlation coefficient (r and r (2)), the ratio between regression and residual variances (f, Fisher's statistic), the standard error of estimates and

  15. Fungitoxicidade, atividade elicitora de fitoalexinas e proteção de alface em sistema de cultivo orgânico contra Sclerotinia sclerotiorum pelo extrato de gengibre Fungitoxicity, phytoalexins elicitor activity and protection of grown against Sclerotinia sclerotiorum by ginger extract

    Directory of Open Access Journals (Sweden)

    Edvirgem Rodrigues

    2007-06-01

    Full Text Available O patógeno Sclerotinia sclerotiorum é um fungo que sobrevive no solo e causa a doença conhecida como mofo branco ou podridão de esclerotínia na cultura da alface (Lactuca sativa e outras culturas. A doença é considerada de difícil controle, uma vez que o fungo é muito agressivo e produzem estruturas de resistência, os escleródios. Na busca de novos métodos de controle de doenças, os extratos de plantas com propriedades terapêuticas surgem como opção. Neste trabalho avaliou-se o efeito do extrato bruto aquoso (EBA de gengibre (Zingiber officinalis nas concentrações de 1, 5, 10, 15, 20 e 25% sobre o crescimento micelial e produção de escleródios de S. sclerotiorum, in vitro. Também foi verificada a eficiência do gengibre na proteção de plantas de alface cultivadas organicamente e inoculadas com o patógeno. Além da incidência da doença, foi analisado o rendimento da cultura e a atividade de peroxidase nos tecidos da planta. Água e o indutor de resistência acibenzolar-S-metil foram utilizados como tratamentos controle. Adicionalmente, a capacidade elicitora do EBA de gengibre em proporcionar o acúmulo das fitoalexinas deoxiantocianidina e gliceolina foi avaliada em bioensaios com sorgo e soja, respectivamente. Os resultados indicaram a atividade antimicrobiana dos EBA de gengibre, com inibição do crescimento micelial e da produção de escleródios. Na cultura da alface, verificou-se que a aplicação de massa de gengibre na base da planta aumentou a atividade da enzima peroxidase e reduziu a incidência da doença. A presença de compostos elicitores no EBA de gengibre foi observada pela indução da produção de fitoalexinas em sorgo e soja, que ocorreu de maneira dose-dependente. Estes resultados indicam o potencial de Z. officinalis para o controle de S. sclerotiorum em alface, o qual pode ocorrer tanto por atividade antimicrobiana direta quanto pela ativação de mecanismos de defesa das plantas

  16. Erwinia pyrifoliae, a new pathogen on strawberry in the Netherlands

    NARCIS (Netherlands)

    Wenneker, M.; Bergsma-Vlami, M.M.

    2015-01-01

    BACKGROUND: During the late spring of 2013 strawberry plants grown under protection (Fragaria x ananassa cv. Elsanta) were found at several locations in the Netherlands showing an intense brown to black discoloration of their immature fruits, their fruit calyx and the attached stems. OBJECTIVE:

  17. Systems and models of fire blight (Erwinia amylovora prediction

    Directory of Open Access Journals (Sweden)

    Krzysztof Kielak

    2013-12-01

    Full Text Available The paper presents fire blight prediction models and systems, developed in Europe (system Billing - versions: BOS, BRS, BIS95 and originated from this system: Firescreen, FEUERBRA and ANLAFBRA and in United States (Californian system, model Maryblyt and system Cougarblight. Use of above models and systems in various climatic-geographic conditions and comparison of obtained prognostic data to real fire blight occurrence is reviewed. The newest trends in research on improvement of prognostic analyses parameters with their adjustment to particular conditions and consideration of infection source occurrence are also presented.

  18. Membrane Vesicles and Lactamase in Erwinia herbicola Essam A ...

    African Journals Online (AJOL)

    yakoub@AHMED

    lactamase inhibitor combination. Journal of the American Veterinary Medical. Association 218: 1893-1896. Medeiros AA (1997) -Lactamases: quality and resistance. Clinical Microbiology & Infection 4: S2-S9. Minami S, Yotsuji A, Inoue M ...

  19. Isoxazole derivatives as new nitric oxide elicitors in plants

    Directory of Open Access Journals (Sweden)

    Anca Oancea

    2017-04-01

    Full Text Available Several 3,5-disubstituted isoxazoles were obtained in good yields by regiospecific 1,3-dipolar cycloaddition reactions between aromatic nitrile oxides, generated in situ from the corresponding hydroxyimidoyl chlorides, with non-symmetrical activated alkynes in the presence of catalytic amounts of copper(I iodide. Effects of 3,5-disubstituted isoxazoles on nitric oxide and reactive oxygen species generation in Arabidopsis tissues was studied using specific diaminofluoresceine dyes as fluorescence indicators.

  20. Purification of an elicitor from Magnaporthe oryzae inducing defense ...

    African Journals Online (AJOL)

    Yomi

    2012-04-12

    Apr 12, 2012 ... Quiroga M, Guerrero C, Botella MA, Barcelo A, Amaya I, Medina MI,. Alonso FJ, De Forchetti SM, Tigier H, Valpuesta V (2000). A tomato peroxidase involved in the synthesis of lignin and suberin. Plant. Physiol. 122: 1119-1127. Rossman AY, Howard RJ, Valent B (1990). Pyricularia oryzae, the correct name ...

  1. Growth promotion and elicitor activity of salicylic acid in Achillea ...

    African Journals Online (AJOL)

    ... with a consequent improvement of the antioxidant activity of the plant extract. It can be concluded that SA application constitutes an advantageous management practice for commercial production of Achillea millefolium, increasing the nutraceutical and medicinal values of this species. Key words: Photosynthetic pigments, ...

  2. Use of elicitors as an approach for sustainable agriculture

    African Journals Online (AJOL)

    Yomi

    2010-12-29

    IR) and consequently activation of plant immunity to ... has been made in understanding the molecular mechanisms governing ... changes in gene expression and cell wall reinforcement. (Zipfel, 2008). Besides PTI, a second ...

  3. Characterization of a broad range antibacterial substance from a new Bacillus species isolated from Amazon basin.

    Science.gov (United States)

    Motta, Amanda S; Cannavan, Fabiana S; Tsai, Siu-Mui; Brandelli, Adriano

    2007-10-01

    A Bacillus sp. strain producing a bacteriocin-like substance was characterized by biochemical profiling and 16S rDNA sequencing. The phylogenetic analysis indicated that this strain has low sequence similarity with most Bacillus spp., suggesting a new species was isolated. The antimicrobial activity was detected starting at the exponential growth phase, and maximum activity was observed at stationary phase. The substance was inhibitory to a broad range of indicator strains, including pathogenic and food spoilage bacteria such as Listeria monocytogenes, B. cereus, Aeromonas hydrophila, Erwinia carotovora, Pasteurella haemolytica, Salmonella Gallinarum, among other. The antibacterial substance was stable over a wide pH range, but it was sensitive to pronase E and lipase. The antibacterial substance was bactericidal and bacteriolytic to L. monocytogenes and B. cereus at 160 AU ml(-1). The identification of a broad range bacteriocin-like inhibitory substance active against L. monocytogenes addresses an important aspect of food protection against pathogens and spoilage microorganisms.

  4. [Transgenic Belarussian-bred potato plants expressing genes for antimicrobial peptides of the cecropin-melittin type].

    Science.gov (United States)

    Vutto, N L; Gapeeva, T A; Pundik, A N; Tret'iakova, T G; Volotovskiĭ, I D

    2010-12-01

    Binary vectors for Agrobacterium-mediated transformation were constructed to express the genes for antimicrobial peptides (APs) of the cectropin-melittin type under the control of the cauliflower mosaic virus 35S RNA promoter in plants. It was shown with Escherichia coli and Agrobacterium tumefaciens cells that the cassettes could be cloned in pB1121-based vectors with deletion of the 3-D-glycuronidase gene only in the orientation opposite to that of the original vector. Transgenic potato plants were obtained using the Belarussian varieties Odyssey, Vetraz, and Scarb. Their cells expressed the MsrA1 or CEMA peptides of the cecropin-melittin type. The expression was shown to confer higher resistance to bacterial (Erwinia carotovora) infection and extremely high resistance to fungal (Phytophtora infestans and Alternarla solani) infections.

  5. The Antibacterial Activity of Chitosan Products Blended with Monoterpenes and Their Biofilms against Plant Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Mohamed E. I. Badawy

    2016-01-01

    Full Text Available This study focuses on the biological activities of eleven chitosan products with a viscosity-average molecular weight ranging from 22 to 846 kDa in combination with the most active monoterpenes (geraniol and thymol, out of 10 tested, against four plant pathogenic bacteria, Agrobacterium tumefaciens, Erwinia carotovora, Corynebacterium fascians, and Pseudomonas solanacearum. The antibacterial activity was evaluated in vitro by the agar dilution technique as a minimum inhibitory concentration (MIC that was found to be dependent on the type of the microorganism tested. The most active product of chitosan was used for biofilm production enriched with geraniol and thymol (0.1 and 0.5% and the films were also evaluated against the tested bacteria. The biological bioactivities summarized here may provide novel insights into the functions of chitosan and some monoterpenes and potentially allow their use for food protection from microbial attack.

  6. Development and application of pathovar-specific monoclonal antibodies that recognize the lipopolysaccharide O antigen and the type IV fimbriae of Xanthomonas hyacinthi

    Energy Technology Data Exchange (ETDEWEB)

    Doorn, J. van; Ojanen-Reuhs, T.; Hollinger, T.C.; Reuhs, B.L.; Schots, A.; Boonekamp, P.M.; Oudega, B.

    1999-09-01

    The objective of this study was to develop a specific immunological diagnostic assay for yellow disease in hyacinths, using monoclonal antibodies (MAbs). Mice were immunized with a crude cell wall preparation (shear fraction) from Xanthomonas hyacinthi and with purified type IV fimbriae. Hybridomas were screened for a positive reaction with X. hyacinthi cells or fimbriae and for a negative reaction with X. translucens pv. graminis or Erwinia carotovora subsp. carotovora. Nine MAbs recognized fimbrial epitopes, as shown by immunoblotting, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), and immunoelectron microscopy; however, three of these MAbs had weak cross-reactions with two X. translucens pathovars in immunoblotting experiments. Seven MAbs reacted with lipopolysaccharides and yielded a low-mobility ladder pattern on immunoblots. Subsequent analysis of MAb 2E5 showed that it specifically recognized an epitope on the O antigen, which was found to consist of rhamnose and fucose in a 2:1 molar ratio. The cross-reaction of MAb 2E5 with all X. hyacinthi strains tested showed that this O antigen is highly conserved within this species. MAb 1B10 also reacted with lipopolysaccharides. MAbs 2E5 and 1B10 were further tested in ELISA and immunoblotting experiments with cells and extracts from other pathogens. No cross-reaction was found with 27 other Xanthomonas pathovars tested or with 14 other bacterial species from other genera, such as Erwinia and Pseudomonas, indicating the high specificity of these antibodies. MAbs 2E5 and 1B10 were shown to be useful in ELISA for the detection of X. hyacinthi in infected hyacinths.

  7. Assessment of genetic variability of haploids extracted from tetraploid (2n = 4x = 48) Solanum tuberosum.

    Science.gov (United States)

    Ercolano, M R; Carputo, D; Li, J; Monti, L; Barone, A; Frusciante, L

    2004-08-01

    The objectives of this study were to assess the genetic variability of haploids (2n = 2x = 24) extracted from tetraploid Solanum tuberosum through 4x x 2x crosses with Solanum phureja. Molecular and phenotypic analyses were performed to fingerprint the genotypes used and to evaluate their potential use in breeding programs. AFLP analysis revealed the presence of specific bands derived from the tetraploid seed parent S. phureja, as well as ex novo originated bands. On average, 210 bands were visualized per genotype, 149 (70%) of which were common to both parental genotypes. The percentage of S. tuberosum specific bands ranged from 25.1% to 18.6%, with an average of 22%. The fraction of genome coming from S. phureja ranged from 1.9% to 6.5%, with an average value of 4%. The percentage of ex novo bands varied from 1.9% to 9.0%. The presence of S. phureja DNA is very interesting because it indicated that S. phureja pollinator is involved in the mechanism of haploid formation. The characterization for resistance to Erwinia carotovora subsp. carotovora and potato virus X (PVX) provided evidence that haploids may express traits that are lacking in the tetraploids they come from, which can be useful for both genetic studies and breeding purposes. It is noteworthy that genotypes combining resistance to both diseases and good pollen stainability were identified. Other possible breeding implications owing to the presence of S. phureja genome in the haploids analyzed are discussed.

  8. Identification and Pathogenicity of Phytopathogenic Bacteria Associated with Soft Rot Disease of Girasole Tuber

    Directory of Open Access Journals (Sweden)

    Mamdoh Ewis ISMAIL

    2012-02-01

    Full Text Available During 2010-2011 growing seasons six bacterial isolates were separated from naturally infected girasole plants tubers (Helianthus tuberosus L. cv. �Balady�, showing soft rot, collected from experimental Farm of the Faculty of Agriculture, in El-Minia University, Egypt. Pathogenicity tests showed various virulence for the bacteria isolated from girasole tubers, found pathogenic. These organisms were characterized as rod-shaped, Gram negative, ?-methyl-d-glucoside medium, reducing substances from sucrose, phos, phatase activity and deep cavities on pectate medium. Otherwise, diagnostic tests suggested that the pathogen was Erwinia carotovora ssp. carotovora. The isolated bacteria caused soft rot of wounded tubers when inoculated into tissues. The bacterial isolates were compared for their degree of pathogenicity as well as for differences in specific symptoms, induced in different hosts. The tested isolates could infect several host ranges, such as fruits of apricot, apple, olive, lemon, squash, eggplant and potato tubers, bulbs and garlic and onion cloves, roots radish, carrot, sweet potato and rape. On the other hand, no symptoms were exhibited on pods of bean and cowpea, faba bean, fruits of pepper and tomato. The extracts of experimentally diseased girasole tubers were active in pectinase and also in caboxymethyl cellulose at pH 6 compared to enzyme activities in healthy tissues. Also, the isolated bacteria increased the total and reducing sugars in infected tissues.

  9. [Induction of polygalacturonases important in pathogenicity of Pseudomonas solanacearum

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Recent studies on the importance of hydroxyproline-rich glycoproteins (HPRG's) in the nature and function of plant cell walls have led to the question as to whether proteolytic enzymes are also involved in tissue maceration and act in concert with other cell wall degrading enzymes in the process. The primary objective of this research was to determine whether proteolytic enzymes, in combination with other enzymes, are involved in the degradation of plant cell walls and thus may be essential for pathogenesis by certain soft rot bacteria. The proteolytic enzymes of Erwinia carotovora subsp.carotovora (Ecc) grown on various media were examined by isoelectrofocusing in polyacrylamide gels over a pH range of 3-10. In addition to the main protease present in culture filtrates, low concentrations of several other proteases were present in extracts from potato tubers infected by Ecc. These enzymes degraded gelatin, soluble collagen, and Hide Powder Azure, and showed weak activity on casein, but did not degrade insoluble collagen or elastin. Ecc proteases appear capable of degrading at least one type of cell wall protein in vitro, but we were unable to obtain evidence that these proteases can attack cell wall proteins in muro. The results indicate that some glycosidic alkali- labile bonds have to be broken befor Ecc proteases can degrade cell wall proteins. Thus, these proteases may play a role in cell wall degradation only when acting in concert with other enzymes that split glycosidic bonds.

  10. Control of Postharvest Bacterial Soft Rot by Gamma Irradiation and its Potential Modes of Action

    Directory of Open Access Journals (Sweden)

    Rae-Dong Jeong

    2016-04-01

    Full Text Available Gamma irradiation was evaluated for its in vitro and in vivo antibacterial activity against a postharvest bacterial pathogen, Erwinia carotovora subsp. carotovora (Ecc. Gamma irradiation in a bacteria cell suspension resulted in a dramatic reduction of the viable counts as well as an increase in the amounts of DNA and protein released from the cells. Gamma irradiation showed complete inactivation of Ecc, especially at a dose of 0.6 kGy. In addition, scanning electron microscopy of irradiated cells revealed severe damage on the surface of most bacterial cells. Along with the morphological changes of cells by gamma irradiation, it also affected the membrane integrity in a dose-dependent manner. The mechanisms by which the gamma irradiation decreased the bacterial soft rot can be directly associated with the disruption of the cell membrane of the bacterial pathogen, along with DNA fragmentation, results in dose-dependent cell inactivation. These findings suggest that gamma irradiation has potential as an antibacterial approach to reduce the severity of the soft rot of paprika.

  11. Rudra interrupts receptor signaling complexes to negatively regulate the IMD pathway.

    Directory of Open Access Journals (Sweden)

    Kamna Aggarwal

    2008-08-01

    Full Text Available Insects rely primarily on innate immune responses to fight pathogens. In Drosophila, antimicrobial peptides are key contributors to host defense. Antimicrobial peptide gene expression is regulated by the IMD and Toll pathways. Bacterial peptidoglycans trigger these pathways, through recognition by peptidoglycan recognition proteins (PGRPs. DAP-type peptidoglycan triggers the IMD pathway via PGRP-LC and PGRP-LE, while lysine-type peptidoglycan is an agonist for the Toll pathway through PGRP-SA and PGRP-SD. Recent work has shown that the intensity and duration of the immune responses initiating with these receptors is tightly regulated at multiple levels, by a series of negative regulators. Through two-hybrid screening with PGRP-LC, we identified Rudra, a new regulator of the IMD pathway, and demonstrate that it is a critical feedback inhibitor of peptidoglycan receptor signaling. Following stimulation of the IMD pathway, rudra expression was rapidly induced. In cells, RNAi targeting of rudra caused a marked up-regulation of antimicrobial peptide gene expression. rudra mutant flies also hyper-activated antimicrobial peptide genes and were more resistant to infection with the insect pathogen Erwinia carotovora carotovora. Molecularly, Rudra was found to bind and interfere with both PGRP-LC and PGRP-LE, disrupting their signaling complex. These results show that Rudra is a critical component in a negative feedback loop, whereby immune-induced gene expression rapidly produces a potent inhibitor that binds and inhibits pattern recognition receptors.

  12. Isolation, Characterization, and Identification of Biological Control Agent for Potato Soft Rot in Bangladesh

    Directory of Open Access Journals (Sweden)

    M. M. Rahman

    2012-01-01

    Full Text Available A total of 91 isolates of probable antagonistic bacteria of potato soft rot bacterium Erwinia carotovora subsp. carotovora (Ecc were extracted from rhizospheres and endophytes of various crop plants, different soil varieties, and atmospheres in the potato farming areas of Bangladesh. Antibacterial activity of the isolated probable antagonistic bacteria was tested in vitro against the previously identified most common and most virulent soft rot causing bacterial strain Ecc P-138. Only two isolates E-45 and E-65 significantly inhibited the in vitro growth of Ecc P-138. Physiological, biochemical, and carbon source utilization tests identified isolate E-65 as a member of the genus Bacillus and the isolate E-45 as Lactobacillus sp. The stronger antagonistic activity against Ecc P-138 was found in E-65 in vitro screening and storage potatoes. E-65 reduced the soft rot infection to 22-week storage potatoes of different varieties by 32.5–62.5% in model experiment, demonstrating its strong potential to be used as an effective biological control agent for the major pectolytic bacteria Ecc. The highest (62.5% antagonistic effect of E-65 was observed in the Granola and the lowest (32.7% of that was found in the Cardinal varieties of the Bangladeshi potatoes. The findings suggest that isolate E-65 could be exploited as a biocontrol agent for potato tubers.

  13. Identification and Pathogenicity of Phytopathogenic Bacteria Associated with Soft Rot Disease of Girasole Tuber

    Directory of Open Access Journals (Sweden)

    Mamdoh Ewis ISMAIL

    2012-02-01

    Full Text Available During 2010-2011 growing seasons six bacterial isolates were separated from naturally infected girasole plants tubers (Helianthus tuberosus L. cv. Balady, showing soft rot, collected from experimental Farm of the Faculty of Agriculture, in El-Minia University, Egypt. Pathogenicity tests showed various virulence for the bacteria isolated from girasole tubers, found pathogenic. These organisms were characterized as rod-shaped, Gram negative, ?-methyl-d-glucoside medium, reducing substances from sucrose, phos, phatase activity and deep cavities on pectate medium. Otherwise, diagnostic tests suggested that the pathogen was Erwinia carotovora ssp. carotovora. The isolated bacteria caused soft rot of wounded tubers when inoculated into tissues. The bacterial isolates were compared for their degree of pathogenicity as well as for differences in specific symptoms, induced in different hosts. The tested isolates could infect several host ranges, such as fruits of apricot, apple, olive, lemon, squash, eggplant and potato tubers, bulbs and garlic and onion cloves, roots radish, carrot, sweet potato and rape. On the other hand, no symptoms were exhibited on pods of bean and cowpea, faba bean, fruits of pepper and tomato. The extracts of experimentally diseased girasole tubers were active in pectinase and also in caboxymethyl cellulose at pH 6 compared to enzyme activities in healthy tissues. Also, the isolated bacteria increased the total and reducing sugars in infected tissues.

  14. Potential application of Northern Argentine propolis to control some phytopathogenic bacteria.

    Science.gov (United States)

    Ordóñez, R M; Zampini, I C; Moreno, M I Nieva; Isla, M I

    2011-10-20

    The antimicrobial activity of samples of Northern Argentine propolis (Tucumán, Santiago del Estero and Chaco) against phytopathogenic bacteria was assessed and the most active samples were identified. Minimal inhibitory concentration (MIC) values were determined by agar macrodilution and broth microdilution assays. Strong antibacterial activity was detected against Erwinia carotovora spp carotovora CECT 225, Pseudomonas syringae pvar tomato CECT 126, Pseudomonas corrugata CECT 124 and Xanthomonas campestris pvar vesicatoria CECT 792. The most active propolis extract (Tucumán, T1) was selected to bioguide isolation and identified for antimicrobial compound (2',4'-dihydroxychalcone). The antibacterial chalcone was more active than the propolis ethanolic extract (MIC values of 0.5-1 μg ml(-1) and 9.5-15 μg ml(-1), respectively). Phytotoxicity assays were realized and the propolis extracts did not retard germination of lettuce seeds or the growth of onion roots. Propolis solutions applied as sprays on tomato fruits infected with P. syringae reduced the severity of disease. Application of the Argentine propolis extracts diluted with water may be promising for the management of post harvest diseases of fruits. Copyright © 2010 Elsevier GmbH. All rights reserved.

  15. Penicitroamide, an Antimicrobial Metabolite with High Carbonylization from the Endophytic Fungus Penicillium sp. (NO. 24

    Directory of Open Access Journals (Sweden)

    Zi-Wei Feng

    2016-10-01

    Full Text Available Penicitroamide (1, a new metabolite with a new framework, was isolated from the ethyl acetate extract of the PDB (Potato Dextrose Broth medium of Penicillium sp. (NO. 24. The endophytic fungus Penicillium sp. (NO. 24 was obtained from the healthy leaves of Tapiscia sinensis Oliv. The structure of penicitroamide (1 features a bicyclo[3.2.1]octane core unit with a high degree of carbonylization (four carbonyl groups and one enol group. The chemical structure of penicitroamide (1 was elucidated by analysis of 1D-, 2D-NMR and MS data. In bioassays, penicitroamide (1 displayed antibacterial potency against two plant pathogens, Erwinia carotovora subsp. Carotovora (Jones Bersey, et al. and Sclerotium rolfsii Sacc. with MIC50 at 45 and 50 μg/mL. Compound 1 also showed 60% lethality against brine shrimp at 10 μg/mL. Penicitroamide (1 exhibited no significant activity against A549, Caski, HepG2 and MCF-7 cells with IC50 > 50 μg/mL. Finally, the possible biosynthetic pathway of penicitroamide (1 was discussed.

  16. Plant Growth-Promoting Genes can Switch to be Virulence Factors via Horizontal Gene Transfer.

    Science.gov (United States)

    Stritzler, Margarita; Soto, Gabriela; Ayub, Nicolás

    2018-02-23

    There are increasing evidences that horizontal gene transfer (HGT) is a critical mechanism of bacterial evolution, while its complete impact remains unclear. A main constraint of HGT effects on microbial evolution seems to be the conservation of the function of the horizontally transferred genes. From this perspective, inflexible nomenclature and functionality criteria have been established for some mobile genetic elements such as pathogenic and symbiotic islands. Adhesion is a universal prerequisite for both beneficial and pathogenic plant-microbe interactions, and thus, adhesion systems (e.g., the Lap cluster) are candidates to have a dual function depending on the genomic background. In this study, we showed that the virulent factor Lap of the phytopathogen Erwinia carotovora SCRI1043, which is located within a genomic island, was acquired by HGT and probably derived from Pseudomonas. The transformation of the phytopathogen Erwinia pyrifoliae Ep1/96 with the beneficial factor Lap from the plant growth-promoting bacterium Pseudomonas fluorescens Pf-5 significantly increased its natural virulence, experimentally recapitulating the beneficial-to-virulence functional switch of the Lap cluster via HGT. To our knowledge, this is the first report of a functional switch of an individual gene or a cluster of genes mediated by HGT.

  17. Rhizosphere bacteria affected by transgenic potatoes with antibacterial activities compared with the effects of soil, wild-type potatoes, vegetation stage and pathogen exposure.

    Science.gov (United States)

    Rasche, Frank; Hödl, Verania; Poll, Christian; Kandeler, Ellen; Gerzabek, Martin H; van Elsas, Jan D; Sessitsch, Angela

    2006-05-01

    A greenhouse experiment was performed to analyze a potential effect of genetically modified potatoes expressing antibacterial compounds (attacin/cecropin, T4 lysozyme) and their nearly isogenic, nontransformed parental wild types on rhizosphere bacterial communities. To compare plant transformation-related variations with commonly accepted impacts caused by altered environmental conditions, potatoes were cultivated under different environmental conditions, for example using contrasting soil types. Further, plants were challenged with the blackleg pathogen Erwinia carotovora ssp. atroseptica. Rhizosphere soil samples were obtained at the stem elongation and early flowering stages. The activities of various extracellular rhizosphere enzymes involved in the C-, P- and N-nutrient cycles were determined as the rates of fluorescence of enzymatically hydrolyzed substrates containing the highly fluorescent compounds 4-methylumbelliferone or 7-amino-4-methyl coumarin. The structural diversity of the bacterial communities was assessed by 16S rRNA-based terminal restriction fragment length polymorphism analysis, and 16S rRNA gene clone libraries were established for the flowering conventional and T4 lysozyme-expressing Desirée lines grown on the chernozem soil, each line treated with and without E. carotovora ssp. atroseptica. Both genetic transformation events induced a differentiation in the activity rates and structures of associated bacterial communities. In general, T4 lysozyme had a stronger effect than attacin/cecropin. In comparison with the other factors, the impact of the genetic modification was only transient and minor, or comparable to the dominant variations caused by soil type, plant genotype, vegetation stage and pathogen exposure.

  18. Epidemiology of Erwinia pyrifoliae, a new pathogen on strawberry in the Netherlands

    NARCIS (Netherlands)

    Wenneker, M.; Bergsma-Vlami, M.; Steen, van der J.J.M.

    2017-01-01

    During the late spring of 2013 strawberry plants (Fragaria × ananassa Duch. 'Elsanta') were showing an intense blackening of their immature fruits, their fruit calyxes and the peduncule were found at several locations (greenhouses) in The Netherlands. Symptoms include brown petals, green young

  19. Optical properties of Erwinia herbicola bacteria at 0.190-2.50 microm.

    Science.gov (United States)

    Arakawa, E T; Tuminello, P S; Khare, B N; Milham, M E

    2003-01-01

    We measure the complex index of refraction of Erwina herbicola (also known as Enterobacter agglomerans or Pantoea agglomerans) bacteria (ATTC 33243) over the spectral region from 0.190 to 2.50 microm (4000-52,632 cm(-1)). Transmission measurements are made on solid films of E. herbicola and on suspensions of the bacteria in water. These measurements, combined with spectral reflectance and Kramers-Krönig analysis, allow the determination of the real and imaginary parts over the entire wavelength interval. Accurate and consistent results are obtained for this complex and difficult to measure material. This is part of a continuing series of measurements of the optical constants of representative biological materials that are applicable to the development of methods for detection of airborne biological contaminants, where the material under study is used as a surrogate for a pathogenic agent. Copyright 2003 Wiley Periodicals, Inc.

  20. Effect of chemical systemic acquired resistance elicitors on avenanthramide biosynthesis in oat (Avena sativa).

    Science.gov (United States)

    Wise, Mitchell L

    2011-07-13

    Oats produce a group of phenolic antioxidants termed avenanthramides. These metabolites are, among food crops, unique to oats and have shown, in experimental systems, certain desirable nutritional characteristics such as inhibiting atherosclerotic plaque formation and reducing inflammation. Avenanthramides occur in both the leaves and grain of oat. In the leaves they are expressed as phytoalexins in response to crown rust (Puccina coronata) infection. The experiments reported here demonstrate that avenanthramide levels in vegetative tissue can be enhanced by treatment with benzothiadiazole (BTH), an agrochemical formulated to elicit systemic acquired resistance (SAR). The response to BTH was dramatically stronger than those produced with salicylic acid treatment. The roots of BTH treated plants also showed a smaller but distinct increase in avenanthramides. The dynamics of the root avenanthramide increase was substantially slower than that observed in the leaves, suggesting that avenanthramides might be transported from the leaves.

  1. Elicitor and fusarium-induced expression of NPR-1 like genes in banana

    CSIR Research Space (South Africa)

    Endah, R

    2008-11-01

    Full Text Available NPR1 is an essential positive regulator of salicylic acid-induced PR gene expression and systemic acquired resistance. Two novel full-length NPR1-like genes; MNPR1A and MNPR1B, were isolated by application of the PCR and RACE techniques. The two...

  2. "What Makes You Shy?": Understanding Situational Elicitors of Shyness in Chinese Children

    Science.gov (United States)

    Xu, Yiyuan; Farver, Jo Ann M.

    2009-01-01

    This paper reports on two exploratory studies of situations that elicit shyness in Mainland Chinese children. In Study 1 (N = 100; M[subscript age] = 10.42) interviews with Chinese children identified three kinds of shyness-eliciting situations: social novelty; negative social evaluation; and public attention. In Study 2 (N = 162, M[subscript age]…

  3. The AVR9 elicitor peptide of the tomato pathogen Cladosporium fulvum : molecular aspects of recognition

    NARCIS (Netherlands)

    Kooman - Gersmann, M.

    1998-01-01

    The interaction between the fungal pathogen Cladosporium fulvum and tomato has been used as a model system to study the molecular basis of gene-for-gene relationships. C. fulvum is a specialized, biotrophic pathogen, which causes leaf mold on

  4. Harzianolide, a novel plant growth regulator and systemic resistance elicitor from Trichoderma harzianum.

    Science.gov (United States)

    Cai, Feng; Yu, Guanghui; Wang, Ping; Wei, Zhong; Fu, Lin; Shen, Qirong; Chen, Wei

    2013-12-01

    A detailed understanding of the effect of natural products on plant growth and protection will underpin new product development for plant production. The isolation and characterization of a known secondary metabolite named harzianolide from Trichoderma harzianum strain SQR-T037 were described, and the bioactivity of the purified compound as well as the crude metabolite extract in plant growth promotion and systemic resistance induction was investigated in this study. The results showed that harzianolide significantly promoted tomato seedling growth by up to 2.5-fold (dry weight) at a concentration of 0.1 ppm compared with the control. The result of root scan suggested that Trichoderma secondary metabolites may influence the early stages of plant growth through better root development for the enhancement of root length and tips. Both of the purified harzianolide and crude metabolite extract increased the activity of some defense-related enzymes to response to oxidative stress. Examination of six defense-related gene expression by real-time reverse transcription-PCR analysis revealed that harzianolide induces the expression of genes involved in the salicylic acid (PR1 and GLU) and jasmonate/ethylene (JERF3) signaling pathways while crude metabolite extract inhibited some gene expression (CHI-II and PGIP) related to basal defense in tomato plants. Further experiment showed that a subsequent challenge of harzianolide-pretreated plants with the pathogen Sclerotinia sclerotiorum resulted in higher systemic resistance by the reduction of lesion size. These results indicate that secondary metabolites of Trichoderma spp., like harzianolide, may play a novel role in both plant growth regulation and plant defense responses. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  5. Phytotoxins, elicitors and other secondary metabolites from phytopathogenic "blackleg" fungi: structure, phytotoxicity and biosynthesis.

    Science.gov (United States)

    Pedras, M Soledade C; Yu, Yang

    2009-09-01

    The metabolites produced by the fungal species Leptosphaeria maculans and L. biglobosa under different culture conditions, together with their phytotoxic activities are reviewed. In addition, the biosynthetic studies of blackleg metabolites carried out to date are described and suggestions for species reclassification are provided.

  6. Impact of elicitors on glucosinolate production in plants and exudates of turnip (Brassica rapa)

    OpenAIRE

    Smetanska, Iryna

    2006-01-01

    Glucosinolate sind charakteristische sekundäre Pflanzenstoffe der Brassicaceae. Ausgewählte Glucosinolate besitzen nachweislich antikanzerogene, antioxidative sowie antimikrobielle Eigenschaften. Die Extraktion von Glucosinolaten erfolgte bisher aus pflanzlichen Rest- bzw. Abfallmaterial (z.B. Brokkoli-Stiele), in denen oft nur sehr niedrige Konzentrationen an gewünschten, gesundheitsfördernden Gesamtglucosinolaten vorhanden sind. Zudem variiert der Gehalt an Gesamt- und Einzelglucosinolaten ...

  7. Recognition of the Cladosporium fulvum Ecp2 elicitor in tomato and non-host plants

    NARCIS (Netherlands)

    Kock, de M.J.D.

    2004-01-01

    Resistance against the tomato fungal pathogen Cladosporium fulvum is often conferred by Hcr9 genes iliomologues of the ~. fulvum resistance gene Cf-~) that are located in the Milky Way cluster on the short arm of Chromosome 1. These Hcr9 genes mediate recognition of matching fungal avirulence gene

  8. The effect of polysaccharide-degrading wine yeast transformants on the efficiency of wine processing and wine flavour.

    Science.gov (United States)

    Louw, C; La Grange, D; Pretorius, I S; van Rensburg, P

    2006-10-01

    Commercial polysaccharase preparations are applied to winemaking to improve wine processing and quality. Expression of polysaccharase-encoding genes in Saccharomyces cerevisiae allows for the recombinant strains to degrade polysaccharides that traditional commercial yeast strains cannot. In this study, we constructed recombinant wine yeast strains that were able to degrade the problem-causing grape polysaccharides, glucan and xylan, by separately integrating the Trichoderma reesei XYN2 xylanase gene construct and the Butyrivibrio fibrisolvens END1 glucanase gene cassette into the genome of the commercial wine yeast strain S. cerevisiae VIN13. These genes were also combined in S. cerevisiae VIN13 under the control of different promoters. The strains that were constructed were compared under winemaking conditions with each other and with a recombinant wine yeast strain expressing the endo-beta-1,4-glucanase gene cassette (END1) from B. fibrisolvens and the endo-beta-1,4-xylanase gene cassette (XYN4) from Aspergillus niger, a recombinant strain expressing the pectate lyase gene cassette (PEL5) from Erwinia chrysanthemi and the polygalacturonase-encoding gene cassette (PEH1) from Erwinia carotovora. Wine was made with the recombinant strains using different grape cultivars. Fermentations with the recombinant VIN13 strains resulted in significant increases in free-flow wine when Ruby Cabernet must was fermented. After 6 months of bottle ageing significant differences in colour intensity and colour stability could be detected in Pinot Noir and Ruby Cabernet wines fermented with different recombinant strains. After this period the volatile composition of Muscat d'Alexandria, Ruby Cabernet and Pinot Noir wines fermented with different recombinant strains also showed significant differences. The Pinot Noir wines were also sensorial evaluated and the tasting panel preferred the wines fermented with the recombinant strains.

  9. Effectiveness of two-sided UV-C treatments in inhibiting natural microflora and extending the shelf-life of minimally processed 'Red Oak Leaf' lettuce.

    Science.gov (United States)

    Allende, Ana; McEvoy, James L; Luo, Yaguang; Artes, Francisco; Wang, Chien Y

    2006-05-01

    The use of UV-C radiation treatments to inhibit the microbial growth and extend the shelf-life of minimally processed 'Red Oak Leaf' lettuce was investigated. Initially, UV-C resistance of 20 bacterial strains from different genera often associated with fresh produce (Enterobacter, Erwinia, Escherichia, Leuconostoc, Pantoea, Pseudomonas, Rahnela, Salmonella, Serratia and Yersinia) were tested in vitro. Most of the bacterial strains were inhibited with the minimum dose (30 J m(-2)). Erwinia carotovora, Leuconostoc carnosum, Salmonella typhimurium, and Yersinia aldovae were the most resistant strains requiring a UV-C dose of 85 J m(-2) to completely inhibit growth. An in vivo study consisted of treating minimally processed 'Red Oak Leaf' lettuce (Lactuca sativa) with UV-C at three radiation doses (1.18, 2.37 and 7.11 kJ m(-2)) on each side of the leaves and storing the product under passive MAP conditions at 5 degrees C for up to 10 days. The gas composition inside packages varied significantly among the treatments, with CO2 concentrations positively and O2 concentrations negatively correlating with the radiation dose. All the radiation doses were effective in reducing the natural microflora of the product, although the highest doses showed the greatest microbial inhibitions. Taking into account the microbial limit set by Spanish legislation [Boletín Oficial del Estado (BOE), 2001. Normas de higiene para la elaboración, distribución y comercio de comidas preparadas, Madrid, Spain, Real Decreto 3484/2000, pp. 1435-1441], all UV-C treatments extended the shelf-life of the product. However, the 7.11 kJ m(-2) dose induced tissue softening and browning after 7 days of storage at 5 degrees C. Therefore, the use of two sided UV-C radiation, at the proper dose, is effective in reducing the natural microflora and extending the shelf-life of minimally processed 'Red Oak Leaf' lettuce.

  10. Biophysical investigations into the interactions of endotoxins with bile acids.

    Science.gov (United States)

    Fukuoka, Satoshi; Richter, Walter; Howe, Jörg; Andrä, Jörg; Rössle, Manfred; Alexander, Christian; Gutsmann, Thomas; Brandenburg, Klaus

    2012-04-01

    The interaction of selected endotoxin preparations (lipid A from Erwinia carotovora and LPS Re and Ra from Salmonella enterica sv. Minnesota strains R595 and R60, respectively) with selected bile acids was investigated biophysically. Endotoxin aggregates were analyzed for their gel-to-liquid crystalline phase behavior, the type of their aggregates, the conformation of particular functional groups, and their Zeta potential in the absence and presence of the bile acids by applying Fourier-transform infrared spectroscopy, differential scanning calorimetry, measurements of the electrophoretic mobility, and synchrotron radiation X-ray scattering. In addition, the ability of the endotoxins to induce cytokines in human mononuclear cells was tested in the absence and presence of varying concentrations of bile acids. The data show that the endotoxin:bile acid interaction is not governed by Coulomb forces, rather a hydrophobic interaction takes place. This leads to an enhanced formation of the inherent cubic aggregate structures of the endotoxins, concomitant with a slight disaggregation, as evidenced by freeze-fracture electron microscopy. Parallel to this, the addition of bile acids increased the bioactivity of lipid A and, to a lower degree, also that of the tested rough mutant LPS at lower concentrations of the endotoxin preparation, a finding similar as reported for the interaction of other agents such as hemoglobin. These data imply that there are general mechanisms that govern the expression of biological activities of endotoxins.

  11. Stacking of antimicrobial genes in potato transgenic plants confers increased resistance to bacterial and fungal pathogens.

    Science.gov (United States)

    Rivero, Mercedes; Furman, Nicolás; Mencacci, Nicolás; Picca, Pablo; Toum, Laila; Lentz, Ezequiel; Bravo-Almonacid, Fernando; Mentaberry, Alejandro

    2012-01-20

    Solanum tuberosum plants were transformed with three genetic constructions expressing the Nicotiana tabacum AP24 osmotine, Phyllomedusa sauvagii dermaseptin and Gallus gallus lysozyme, and with a double-transgene construction expressing the AP24 and lysozyme sequences. Re-transformation of dermaseptin-transformed plants with the AP24/lysozyme construction allowed selection of plants simultaneously expressing the three transgenes. Potato lines expressing individual transgenes or double- and triple-transgene combinations were assayed for resistance to Erwinia carotovora using whole-plant and tuber infection assays. Resistance levels for both infection tests compared consistently for most potato lines and allowed selection of highly resistant phenotypes. Higher resistance levels were found in lines carrying the dermaseptin and lysozyme sequences, indicating that theses proteins are the major contributors to antibacterial activity. Similar results were obtained in tuber infection tests conducted with Streptomyces scabies. Plant lines showing the higher resistance to bacterial infections were challenged with Phytophthora infestans, Rhizoctonia solani and Fusarium solani. Considerable levels of resistance to each of these pathogens were evidenced employing semi-quantitative tests based in detached-leaf inoculation, fungal growth inhibition and in vitro plant inoculation. On the basis of these results, we propose that stacking of these transgenes is a promising approach to achieve resistance to both bacterial and fungal pathogens. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Synthesis and Antimicrobial Activity of N-(6-Carboxyl Cyclohex-3-ene Carbonyl Chitosan with Different Degrees of Substitution

    Directory of Open Access Journals (Sweden)

    Mohamed E. I. Badawy

    2016-01-01

    Full Text Available Five products of N-(6-carboxyl cyclohex-3-ene carbonyl chitosan as antimicrobial agents were prepared by reaction of chitosan with tetrahydrophthalic anhydride (THPA at different degrees of substitution (DS. The antimicrobial activity was evaluated against four plant bacteria and eight fungi. The results proved that the inhibitory property and water solubility of the synthesized chitosan derivatives, with increase of the DS, exhibited a remarkable improvement over chitosan. The product with a DS of 0.40 was the most active one with MIC of 510, 735, 240, and 385 mg/L against Erwinia carotovora, Ralstonia solanacearum, Rhodococcus fascians, and Rhizobium radiobacter, respectively, and also in mycelial growth inhibition against Alternaria alternata (EC50 = 683 mg/L, Botrytis cinerea (EC50 = 774 mg/L, Botryodiplodia theobromae (EC50 = 501 mg/L, Fusarium oxysporum (EC50 = 500 mg/L, F. solani (EC50 = 260 mg/L, Penicillium digitatum (EC50 = 417 mg/L, Phytophthora infestans (EC50 = 298 mg/L, and Sclerotinia sclerotiorum (EC50 = 763 mg/L. These compounds based on a biodegradable and biocompatible chitosan could be used as potentially antimicrobial agents in crop protection instead of hazardous synthetic pesticides.

  13. Tocopherol, carotene, phenolic contents and antibacterial properties of rose essential oil, hydrosol and absolute.

    Science.gov (United States)

    Ulusoy, Seyhan; Boşgelmez-Tinaz, Gülgün; Seçilmiş-Canbay, Hale

    2009-11-01

    The antioxidant and antibacterial activities, and total phenolic contents of Rosa damascena Mill. flower extracts (absolute, essential oil and hydrosol) were investigated. The chemical compositions of these extracts were analysed by GC-MS. Phenylethyl alcohol (78.38%) was found to be the main constituent of rose absolute, while citrenellol and geraniol were the major compounds (>55%) of rose essential oil and hydrosol. Tocopherol and carotene levels were determined by high performance liquid chromatography (HPLC) analysis. The levels of beta carotene (422.3+/-35.6 ppm), alpha tocopherol (2397.1+/-72.5 ppm) and gamma tocopherol (343.1+/-28.4 ppm) of rose absolute were found to be higher than that of essential oil and hydrosol. Their total phenolic contents were also evaluated. The total phenolic content of the tested extracts varied from 5.2 to 2134.3 GAE/mg L(-1). Rose absolute and essential oil contained high levels of phenolics and demonstrated strong antibacterial activity against Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538), Chromobacterium violaceum (ATCC 12472) and Erwinia carotovora (ATCC 39048) strains.

  14. Antimicrobial and inhibitory enzyme activity of N-(benzyl) and quaternary N-(benzyl) chitosan derivatives on plant pathogens.

    Science.gov (United States)

    Badawy, Mohamed E I; Rabea, Entsar I; Taktak, Nehad E M

    2014-10-13

    Chemical modification of a biopolymer chitosan by introducing quaternary ammonium moieties into the polymer backbone enhances its antimicrobial activity. In the present study, a series of quaternary N-(benzyl) chitosan derivatives were synthesized and characterized by (1)H-NMR, FT-IR and UV spectroscopic techniques. The antimicrobial activity against crop-threatening bacteria Agrobacterium tumefaciens and Erwinia carotovora and fungi Botrytis cinerea, Botryodiplodia theobromae, Fusarium oxysporum and Phytophthora infestans were evaluated. The results proved that the grafting of benzyl moiety or quaternization of the derivatives onto chitosan molecule was successful in inhibiting the microbial growth. Moreover, increase water-solubility of the compounds by quaternization significantly increased the activity against bacteria and fungi. Exocellular enzymes including polygalacturonase (PGase), pectin-lyase (PLase), polyphenol oxidase (PPOase) and cellulase were also affected at 1000 mg/L. These compounds especially quaternary-based chitosan derivatives that have good inhibitory effect should be potentially used as antimicrobial agents in crop protection. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. A Single-Step Purification of Cauliflower Lysozyme and Its Dual Role Against Bacterial and Fungal Plant Pathogens.

    Science.gov (United States)

    Manikandan, Muthu; Balasubramaniam, R; Chun, Se-Chul

    2015-09-01

    A novel lysozyme from cauliflower was purified in a single step, for the first time, using Sephadex G100 column chromatography. The purified lysozyme exhibited a homogenized single band in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and its molecular mass was calculated to be 22.0 kDa. The purified lysozyme showed activity between 30 to 60 °C with 40 °C as the optimum temperature for its maximal activity. Although the purified lysozyme was functional at pH ranges between 3.0 and 9.0, the optimum pH for the enzyme activity was 8.0. By Michaelis-Menten equation, the threshold substrate concentration for the optimal enzyme activity was calculated to be 133.0 μg. The purified lysozyme showed extraordinary activity against plant pathogenic bacteria and fungi. At 10-μg concentrations, it inhibited the growth of plant pathogenic bacteria such as Pseudomonas syringae, Xanthomonas campestris, and Erwinia carotovora exhibiting 4.28, 5.90, and 3.88-fold inhibition, respectively. Further, it also completely inhibited the conidial germination of Archemonium obclavatum and, to a very large extent, other fungal species such as Fusarium solani (79.3 %), Leptosphaeria maculans (88.6 %), Botrytis cinera (73.3 %), Curvularia lunata (68 %), Rhizoctonia solani (79.6 %), and Alternaria alternata (83.6 %).

  16. Characterization of an extensin-modifying metalloprotease: N-terminal processing and substrate cleavage pattern of Pectobacterium carotovorum Prt1

    DEFF Research Database (Denmark)

    Feng, Tao; Nyffenegger, Christian; Højrup, Peter

    2014-01-01

    Compared to other plant cell wall-degrading enzymes, proteases are less well understood. In this study, the extracellular metalloprotease Prt1 from Pectobacterium carotovorum (formerly Erwinia carotovora) was expressed in Escherichia coli and characterized with respect to N-terminal processing......, thermal stability, substrate targets, and cleavage patterns. Prt1 is an autoprocessing protease with an N-terminal signal pre-peptide and a pro-peptide which has to be removed in order to activate the protease. The sequential cleavage of the N-terminus was confirmed by mass spectrometry (MS......) fingerprinting and N-terminus analysis. The optimal reaction conditions for the activity of Prt1 on azocasein were at pH 6.0, 50 °C. At these reaction conditions, KM was 1.81 mg/mL and kcat was 1.82 × 107 U M-1. The enzyme was relatively stable at 50 °C with a half-life of 20 min. Ethylenediaminetetraacetic acid...

  17. CytR Homolog of Pectobacterium carotovorum subsp. carotovorum Controls Air-Liquid Biofilm Formation by Regulating Multiple Genes Involved in Cellulose Production, c-di-GMP Signaling, Motility, and Type III Secretion System in Response to Nutritional and Environmental Signals

    Directory of Open Access Journals (Sweden)

    M. M. Haque

    2017-05-01

    Full Text Available Pectobacterium carotovorum subsp. carotovorum [Pcc (formerly Erwinia carotovora subsp. carotovora] PC1 causes soft-rot disease in a wide variety of plant species by secreting multiple pathogenicity-related traits. In this study, regulatory mechanism of air-liquid (AL biofilm formation was studied using a cytR homolog gene deletion mutant (ΔcytR of Pcc PC1. Compared to the wild type (Pcc PC1, the ΔcytR mutant produced fragile and significantly (P < 0.001 lower amounts of AL biofilm on salt-optimized broth plus 2% glycerol (SOBG, yeast peptone dextrose adenine, and also on King’s B at 27°C after 72 h incubation in static condition. The wild type also produced significantly higher quantities of AL biofilm on SOBGMg– (magnesium deprived containing Cupper (Cu2+, Zinc (Zn2+, Manganese (Mn2+, Magnesium (Mg2+, and Calcium (Ca2+ compared to the ΔcytR mutant. Moreover, the wild type was produced higher amounts of biofilms compared to the mutant while responding to pH and osmotic stresses. The ΔfliC (encoding flagellin, flhD::Tn5 (encoding a master regulator and ΔmotA (a membrane protein essential for flagellar rotation mutants produced a lighter and more fragile AL biofilm on SOBG compared to their wild counterpart. All these mutants resulted in having weak bonds with the cellulose specific dye (Calcofluor producing lower quantities of cellulose compared to the wild type. Gene expression analysis using mRNA collected from the AL biofilms showed that ΔcytR mutant significantly (P < 0.001 reduced the expressions of multiple genes responsible for cellulose production (bcsA, bcsE, and adrA, motility (flhD, fliA, fliC, and motA and type III secretion system (hrpX, hrpL, hrpA, and hrpN compared to the wild type. The CytR homolog was therefore, argued to be able to regulate the AL biofilm formation by controlling cellulose production, motility and T3SS in Pcc PC1. In addition, all the mutants exhibited poorer attachment to radish sprouts and AL

  18. Polymyxin P is the active principle in suppressing phytopathogenic Erwinia spp. by the biocontrol rhizobacterium Paenibacillus polymyxa M-1

    National Research Council Canada - National Science Library

    Niu, Ben; Vater, Joachim; Rueckert, Christian; Blom, Jochen; Lehmann, Maik; Ru, Jin-Jiang; Chen, Xiao-Hua; Wang, Qi; Borriss, Rainer

    2013-01-01

    Nine gene clusters dedicated to nonribosomal synthesis of secondary metabolites with possible antimicrobial action, including polymyxin and fusaricidin, were detected within the whole genome sequence...

  19. Assessment of recent outbreaks of Dickeya sp (syn. Erwinia chrysanthemi) slow wilt in potato crops in Israel

    OpenAIRE

    Tsror, L.; Erlich, O.; Lebiush, S.; Hazanovsky, M.; Zig, U.; Slawiak, M.; Grabe, G.; Wolf, van der, J.M.; Haar, van de, J.J.

    2009-01-01

    Suspected Dickeya sp. strains were obtained from potato plants and tubers collected from commercial plots. The disease was observed on crops of various cultivars grown from seed tubers imported from the Netherlands during the spring seasons of 2004-2006, with disease incidence of 2-30% ( 10% in average). In addition to typical wilting symptoms on the foliage, in cases of severe infection, progeny tubers were rotten in the soil. Six strains were characterised by biochemical, serological and PC...

  20. Assessment of recent outbreaks of Dickeya sp (syn. Erwinia chrysanthemi) slow wilt in potato crops in Israel

    NARCIS (Netherlands)

    Tsror, L.; Erlich, O.; Lebiush, S.; Hazanovsky, M.; Zig, U.; Slawiak, M.; Grabe, G.; Wolf, van der J.M.; Haar, van de J.J.

    2009-01-01

    Suspected Dickeya sp. strains were obtained from potato plants and tubers collected from commercial plots. The disease was observed on crops of various cultivars grown from seed tubers imported from the Netherlands during the spring seasons of 2004-2006, with disease incidence of 2-30% ( 10% in

  1. Transcriptomic responses of the olive fruit fly Bactrocera oleae and its symbiont Candidatus Erwinia dacicola to olive feeding

    OpenAIRE

    Pavlidi, Nena; Gioti, Anastasia; Wybouw, Nicky; Dermauw, Wannes; Ben-Yosef, Michael; Yuval, Boaz; Jurkevich, Edouard; Kampouraki, Anastasia; Van Leeuwen, Thomas; Vontas, John

    2017-01-01

    The olive fruit fly, Bactrocera oleae, is the most destructive pest of olive orchards worldwide. The monophagous larva has the unique capability of feeding on olive mesocarp, coping with high levels of phenolic compounds and utilizing non-hydrolyzed proteins present, particularly in the unripe, green olives. On the molecular level, the interaction between B. oleae and olives has not been investigated as yet. Nevertheless, it has been associated with the gut obligate symbiotic bacterium Candid...

  2. The plant pathogen Erwinia amylovora produces acyl-homoserine lactone signal molecules in vitro and in planta.

    Science.gov (United States)

    Venturi, Vittorio; Venuti, Chiara; Devescovi, Giulia; Lucchese, Carla; Friscina, Arianna; Degrassi, Giuliano; Aguilar, Claudio; Mazzucchi, Umberto

    2004-12-15

    We report for the first time the production of acyl homoserine lactones (AHLs) by Erwina amylovora, an important quarantine bacterial pathogen that causes fire blight in plants. E. amylovora produces one N-acyl homoserine lactone [a N-(3-oxo-hexanoyl)-homoserine lactone or a N-(3-hydroxy-hexanoyl)-homoserine lactone] quorum sensing signal molecule both in vitro and in planta (pear plant). Given the involvement of AHLs in plant pathogenesis, we speculate that AHL-dependent quorum sensing could play an important role in the regulation of E. amylovora virulence.

  3. The Association of Western Flower Thrips, Frankliniella occidentalis, with a near Erwinia Species Gut Bacteria: Transient of Permanent?

    NARCIS (Netherlands)

    de Vries, E.J.; Breeuwer, J.A.J.; Jacobs, G.; Mollema, G.

    2001-01-01

    Associations between insects and gut bacteria are ubiquitous, it is possible to make a distinction between permanent associations (called symbiosis), in which the same type of bacteria is present in more than one generation of the insect, and transient associations. Transient bacteria are ingested

  4. Herbivory induces systemic production of plant volatiles that attract predators of the herbivore: extraction of endogenous elicitor.

    NARCIS (Netherlands)

    Dicke, M.; Baarlen, van P.; Wessels, R.; Dijkman, H.

    1993-01-01

    It was previously shown that in response to infestation by spider mites (Tetranychus urticae), lima bean plants produce a volatile herbivoreinduced synomone that attracts phytoseiid mites (Phytoseiulus persimilis) that are predators of the spider mites. The production of predator-attracting

  5. The Cf-4 and Cf-9 resistance proteins of tomato: molecular aspects of specificity and elicitor perception

    NARCIS (Netherlands)

    Hoorn, van der R.A.L.

    2001-01-01

    To feed the increasing world population, agricultural production needs continuous improvement. Especially protection of crops from disastrous diseases is crucial. The interaction between the pathogenic fungus Cladosporium fulvum and its host,

  6. Chitosan (middle-viscous as an effective elicitor for silymarin production in Silybum marianum hairy root cultures

    Directory of Open Access Journals (Sweden)

    T. Hasanloo

    2014-01-01

    Full Text Available Elicitation with middle-viscous chitosan (30 mg/50 mL significantly stimulated silymarin synthesis in Silybum marianum hairy root cultures. The root cultures established by infection with Agrobacterium rhizogenes AR15834 showed a potential for production of silymarin. Elicitation with medium molecular weight of chitosan (0, 5, 10, 20, and 30 mg/50 mL was used in order to improve silymarin production. Total silymarin increased about 5.26-fold after 96 h of treatment with 30 mg/50 mL chitosan. Dry weight of the hairy roots reached the highest point (0.530 and 0.535 g after 96 h in presence of 20 and 30 mg/50 mL chitosan, respectively. Five different flavonolignans were isolated; taxifolin, silychristin, silydianin, silybin and isosilybin 0.133, 0.200, 0.120, 0.041 and 0.056 mg/g dry weight, respectively. 30 days old hairy roots were treated by 30 mg/50 mL chitosan in different times (12, 24, 48, 72, 96 and 120 h. The amount of silymarin accumulation significantly increased (0.705 mg/gDW in hairy roots after 96 h treatment. These observations suggested that the medium molecular weight of chitosan could be elicited by S. marianum hairy root cultures that lead to the higher production of silymarin. These results correlated with the culture time, and the biosynthesis which reached to a maximum of 0.705 mg/gDW by 96 h after culture. (2.9-fold higher than the control.

  7. Arabidopsis ubiquitin ligase PUB12 interacts with and negatively regulates Chitin Elicitor Receptor Kinase 1 (CERK1.

    Directory of Open Access Journals (Sweden)

    Koji Yamaguchi

    Full Text Available In Arabidopsis, fungal chitin is recognized as a pathogen-associated molecular pattern (PAMP by the chitin receptor complex containing the lysin-motif (LysM receptor-like kinases CERK1 and LYK5. Upon the perception of chitin, CERK1 phosphorylates the receptor-like cytoplasmic kinase, PBL27, which activates the intracellular mitogen-activated protein kinase (MAPK cascade. However, the mechanisms by which the CERK1-PBL27 complex is regulated remain largely unknown. We identified ubiquitin ligase PUB12 as a component of the PBL27 complex using co-immunoprecipitation and mass spectrometry. However, PUB12 did not interact directly with PBL27. Instead, the ARM domains of PUB12 and its paralog PUB13 interacted with the intracellular domain of CERK1 in a manner that was dependent on its autophosphorylation, suggesting that the phosphorylation-based auto-activation of CERK1 may be required for its interaction with PUB12. The co-expression of PUB12 in Nicotiana benthamiana reduced the accumulation of CERK1. The pub12 pub13 mutant exhibited enhanced chitin-induced immune responses such as ROS production, MAPK activation, and callose deposition. These results suggest that PUB12 and PUB13 are involved in the negative regulation of the chitin receptor complex, which may contribute to the transient desensitization of chitin-induced responses.

  8. Effects of polysaccharide elicitors on secondary metabolite production and antioxidant response in Hypericum perforatum L. shoot cultures

    National Research Council Canada - National Science Library

    Gadzovska Simic, Sonja; Tusevski, Oliver; Maury, Stéphane; Delaunay, Alain; Joseph, Claude; Hagège, Daniel

    2014-01-01

    .... The activities of phenylalanine ammonia lyase (PAL) and chalcone-flavanone isomerase (CHFI) were monitored to estimate channeling in phenylpropanoid/flavonoid pathways of elicited shoot cultures...

  9. Comprehensive assessment of the genes involved in withanolide biosynthesis from Withania somnifera: chemotype-specific and elicitor-responsive expression.

    Science.gov (United States)

    Agarwal, Aditya Vikram; Gupta, Parul; Singh, Deeksha; Dhar, Yogeshwar Vikram; Chandra, Deepak; Trivedi, Prabodh Kumar

    2017-07-01

    Withania somnifera (L.) Dunal (Family, Solanaceae), is among the most valuable medicinal plants used in Ayurveda owing to its rich reservoir of pharmaceutically active secondary metabolites known as withanolides. Withanolides are C28-steroidal lactones having a triterpenoidal metabolic origin synthesised via mevalonate (MVA) pathway and methyl-D-erythritol-4-phosphate (MEP) pathway involving metabolic intermediacy of 24-methylene (C30-terpenoid) cholesterol. Phytochemical studies suggest differences in the content and/or nature of withanolides in different tissues of different chemotypes. Though development of genomic resources has provided information about putative genes encoding enzymes for biosynthesis of intermediate steps of terpenoid backbone, not much is known about their regulation and response to elicitation. In this study, we generated detailed molecular information about genes catalysing key regulatory steps of withanolide biosynthetic pathway. The full-length sequences of genes encoding enzymes for intermediate steps of terpenoid backbone biosynthesis and their paralogs have been characterized for their functional and structural properties as well as phylogeny using bioinformatics approach. The expression analysis suggests that these genes are differentially expressed in different tissues (with maximal expression in young leaf), chemotypes and in response to salicylic acid (SA) and methyl jasmonate (MJ) treatments. Sub-cellular localization studies suggest that both paralogs of sterol ∆-7 reductase (WsDWF5-1 and WsDWF5-2) are localized in the endoplasmic reticulum (ER) thus supporting their indispensible role in withanolide biosynthesis. Comprehensive information developed, in this study, will lead to elucidation of chemotype- as well as tissue-specific withanolide biosynthesis and development of new tools for functional genomics in this important medicinal plant.

  10. ß-Glucosidase: an elicitor of herbivore-induced plant odor that attracts host-searching parasitic wasps.

    NARCIS (Netherlands)

    Mattiacci, L.; Dicke, M.; Posthumus, M.A.

    1995-01-01

    Cabbage plants respond to caterpillar (Pieris brassicae) herbivory by releasing a mixture of volatiles that makes them highly attractive to parasitic wasps (Cotesia glomerata) that attack the herbivores. Cabbage leaves that are artificially damaged and subsequently treated with gut regurgitant of P.

  11. Chitosan, Antifungal Product against Fusarium oxysporum f. sp. albedinis and Elicitor of Defence Reactions in Date Palm Roots

    National Research Council Canada - National Science Library

    M. Hassni; A. El Hadrami; F. Daayf; E.A. Barka; I. El Hadrami

    2004-01-01

    The effect of chitosan on the growth and morphology of Fusarium oxysporum f. sp. albedinis (Foa), the causal agent of Bayoud disease, and its ability to elicit a defence reaction against this fungus in date palm roots were investigated...

  12. Inducción de tolerancia a la fusariosis de la espiga mediante el empleo de elicitores hormonales en trigo

    OpenAIRE

    Pintos, Federico

    2016-01-01

    La “fusariosis de la espiga de trigo” (FET) o “golpe blanco”, ocasionada por Fusarium graminearum Schwabe, es una de las enfermedades más importantes que afecta al cultivo de trigo (Triticum aestivum L.) en todas las regiones cerealeras del mundo. Esta patología ocasiona disminuciones del rendimiento, deterioro sobre la calidad del trigo y la contaminación del grano con micotoxinas, que constituyen un riesgo para la salud humana y animal, y comprometen su utilización industrial. En el pres...

  13. The heterologous expression of polysaccharidase-encoding genes with oenological relevance in Saccharomyces cerevisiae.

    Science.gov (United States)

    van Rensburg, P; Strauss, M L A; Lambrechts, M G; Cordero Otero, R R; Pretorius, I S

    2007-12-01

    The main objective of this study was to develop polysaccharide-degrading wine strains of Saccharomyces cerevisiae, which are able to improve aspects of wine processing and clarification, as well as colour extraction and stabilization during winemaking. Two yeast expression/secretion gene cassettes were constructed, namely (i) a pectinase gene cassette (pPPK) consisting of the endo-polygalacturonase gene (pelE) from Erwinia chrysanthemi and the pectate lyase gene (peh1) from Erwinia carotovora and (ii) a glucanase/xylanase gene cassette (pEXS) containing the endo-beta-1,4-glucanase gene (end1) from Butyrivibrio fibrisolvens and the endo-beta-1,4-xylanase gene (xynC) from Aspergillus niger. The commercial wine yeast strain, VIN13, was transformed separately with these two gene cassettes and checked for the production of pectinase, glucanase and xylanase activities. Pinot Noir, Cinsaut and Muscat d'Alexandria grape juices were fermented using the VIN13[pPPK] pectinase- and the VIN13[pEXS] glucanase/xylanase-producing transformants. Chemical analyses of the resultant wines indicated that (i) the pectinase-producing strain caused a decrease in the concentration of phenolic compounds in Pinot Noir whereas the glucanase/xylanase-producing strain caused an increase in phenolic compounds presumably because of the degradation of the grape skins; (ii) the glucanase/xylanase-producing strain caused a decrease in wine turbidity, especially in Pinot Noir wine, as well as a clear increase in colour intensity and (iii) in the Muscat d'Alexandria and Cinsaut wines, the differences between the control wines (fermented with the untransformed VIN3 strain) and the wines produced by the two transformed strains were less prominent showing that the effect of these polysaccharide-degrading enzymes is cultivar-dependent. The recombinant wine yeasts producing pectinase, glucanase and xylanase activities during the fermentation of Pinot Noir, Cinsaut and Muscat d'Alexandria grape juice

  14. Effect of oxygen on the growth and biofilm formation of Xylella fastidiosa in liquid media.

    Science.gov (United States)

    Shriner, Anthony D; Andersen, Peter C

    2014-12-01

    Xylella fastidiosa is a xylem-limited bacterial pathogen, and is the causative agent of Pierce's disease of grapevines and scorch diseases of many other plant species. The disease symptoms are putatively due to blocking of the transpiration stream by bacterial-induced biofilm formation and/or by the formation of plant-generated tylosis. Xylella fastidiosa has been classified as an obligate aerobe, which appears unusual given that dissolved O2 levels in the xylem during the growing season are often hypoxic (20-60 μmol L(-1)). We examined the growth and biofilm formation of three strains of X. fastidiosa under variable O2 conditions (21, 2.1, 0.21 and 0 % O2), in comparison to that of Pseudomonas syringae (obligate aerobe) and Erwinia carotovora (facultative anaerobe) under similar conditions. The growth of X. fastidiosa more closely resembled that of the facultative anaerobe, and not the obligate aerobe. Xanthomonas campestris, the closest genetic relative of X. fastidiosa, exhibited no growth in an N2 environment, whereas X. fastidiosa was capable of growing in an N2 environment in PW(+), CHARDS, and XDM2-PR media. The magnitude of growth and biofilm formation in the N2 (0 % O2) treatment was dependent on the specific medium. Additional studies involving the metabolism of X. fastidiosa in response to low O2 are warranted. Whether X. fastidiosa is classified as an obligate aerobe or a facultative anaerobe should be confirmed by gene activation and/or the quantification of the metabolic profiles under hypoxic conditions.

  15. Antioxidant activity via DPPH, gram-positive and gram-negative antimicrobial potential in edible mushrooms.

    Science.gov (United States)

    Ahmad, Nisar; Mahmood, Fazal; Khalil, Shahid Akbar; Zamir, Roshan; Fazal, Hina; Abbasi, Bilal Haider

    2014-10-01

    Edible mushrooms (EMs) are nutritionally rich source of proteins and essential amino acids. In the present study, the antioxidant activity via 1,1-diphenyl-2-picrylhydrazyl (DPPH) and antimicrobial potential in EMs (Pleurotus ostreatus, Morchella esculenta, P. ostreatus (Black), P. ostreatus (Yellow) and Pleurotus sajor-caju) were investigated. The DPPH radical scavenging activity revealed that the significantly higher activity (66.47%) was observed in Morchella esculenta at a maximum concentration. Similarly, the dose-dependent concentrations (200, 400, 600, 800 and 1000 µg) were also used for other four EMs. Pleurotus ostreatus exhibited 36.13% activity, P. ostreatus (Black (B)) exhibited 30.64%, P. ostreatus (Yellow (Y)) exhibited 40.75% and Pleurotus sajor-caju exhibited 47.39% activity at higher concentrations. Furthermore, the antimicrobial potential were investigated for its toxicity against gram-negative bacterial strains (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Klebsiella pneumonia, Erwinia carotovora and Agrobacterium tumifaciens), gram-positive bacterial strains (Bacillus subtilis, Bacillus atrophaeus and Staphylococcus aureus) and a fungal strain (Candida albicans) in comparison with standard antibiotics. Antimicrobial screening revealed that the ethanol extract of P. ostreatus was active against all microorganism tested except E. coli. Maximum zone of inhibition (13 mm) was observed against fungus and A. tumifaciens. P. sajor-caju showed best activities (12.5 mm) against B. subtilis, B. atrophaeus and K. pneumonia. P. ostreatus (Y) showed best activities against P. aeroginosa (21.83 mm), B. atrophaeus (20 mm) and C. albicans (21 mm). P. ostreatus (B) exhibited best activities against C. albicans (16 mm) and slightly lower activities against all other microbes except S. typhi. M. esculenta possess maximum activities in terms of inhibition zone against all microorganisms tested except S. typhi. © The Author(s) 2012.

  16. Endophytic bacteria associated with growing shoot tips of banana (Musa sp.) cv. Grand Naine and the affinity of endophytes to the host.

    Science.gov (United States)

    Thomas, Pious; Soly, Thyvalappil A

    2009-11-01

    A cultivation-based assessment of endophytic bacteria present in deep-seated shoot tips of banana suckers was made with a view to generate information on the associated organisms, potential endophytic contaminants in tissue-cultured bananas and to assess if the endophytes shared a beneficial relationship with the host. Plating the tissue homogenate from the central core of suckers showed colony growth on nutrient agar from just 75% and 42% of the 12 stocks during May and November, respectively (average 58%; 6 x 10(3) colony-forming units per gram), yielding diverse organisms belonging to firmicutes (Bacillus, Brevibacillus, Paenibacillus, Virgibacillus, Staphylococcus spp.), actinobacteria (Cellulomonas, Micrococcus, Corynebacterium, Kocuria spp.), alpha-proteobacteria (Paracoccus sp.), and gamma-proteobacteria (Pseudomonas, Acinetobacter spp.). Each shoot tip showed one to three different organisms and no specific organism appeared common to different sucker tips. Tissue homogenate from shoot tips including the ones that did not yield culturable bacteria displayed abundant bacterial cells during microscopic examination suggesting that a high proportion of cells were in viable-but-nonculturable state, or their cultivation requirements were not met. Direct application of cultivation-independent approach to study endophytic bacterial community using bacterial 16S ribosomal RNA universal primers resulted in high interference from chloroplast and mitochondrial genome sequences. Dislodging the bacterial cells from shoot tips that did not show cultivable bacteria and incubating the tissue crush in dilute-nutrient broth led to the activation of four organisms (Klebsiella, Agrobacterium, Pseudacidovorax spp., and an unidentified isolate). The endophytic organisms in general showed better growth at 30-37 degrees C compared with 25 degrees C, and the growth of endophytes as well as pathogenic Erwinia carotovora were promoted with the supply of host tissue extract (HTE) while

  17. TrpA1 Regulates Defecation of Food-Borne Pathogens under the Control of the Duox Pathway.

    Directory of Open Access Journals (Sweden)

    Eun Jo Du

    2016-01-01

    Full Text Available Pathogen expulsion from the gut is an important defense strategy against infection, but little is known about how interaction between the intestinal microbiome and host immunity modulates defecation. In Drosophila melanogaster, dual oxidase (Duox kills pathogenic microbes by generating the microbicidal reactive oxygen species (ROS, hypochlorous acid (HOCl in response to bacterially excreted uracil. The physiological function of enzymatically generated HOCl in the gut is, however, unknown aside from its anti-microbial activity. Drosophila TRPA1 is an evolutionarily conserved receptor for reactive chemicals like HOCl, but a role for this molecule in mediating responses to gut microbial content has not been described. Here we identify a molecular mechanism through which bacteria-produced uracil facilitates pathogen-clearing defecation. Ingestion of uracil increases defecation frequency, requiring the Duox pathway and TrpA1. The TrpA1(A transcript spliced with exon10b (TrpA1(A10b that is present in a subset of midgut enteroendocrine cells (EECs is critical for uracil-dependent defecation. TRPA1(A10b heterologously expressed in Xenopus oocytes is an excellent HOCl receptor characterized with elevated sensitivity and fast activation kinetics of macroscopic HOCl-evoked currents compared to those of the alternative TRPA1(A10a isoform. Consistent with TrpA1's role in defecation, uracil-excreting Erwinia carotovora showed higher persistence in TrpA1-deficient guts. Taken together, our results propose that the uracil/Duox pathway promotes bacteria expulsion from the gut through the HOCl-sensitive receptor, TRPA1(A10b, thereby minimizing the chances that bacteria adapt to survive host defense systems.

  18. Gas chromatography coupled with mass spectrometric characterization of Curcuma longa: Protection against pathogenic microbes and lipid peroxidation in rat's tissue homogenate.

    Science.gov (United States)

    Hassan, Waseem; Gul, Shehnaz; Rehman, Shakilla; Kanwal, Farina; Afridi, Muhammad Siddique; Fazal, Hina; Shah, Ziarat; Rahman, Ataur; da Rocha, Joao B T

    2016-03-01

    The present study was designed to investigate the mineral content and antimicrobial activity of Curcuma Longa extracts and its essential oil. We also determined the lipid peroxidation inhibition activity of the ethanolic extract against sodium nitroprusside (SNP) induced thiobarbituric acid reactive species (TBARS) formation in rat's brain, kidney and liver homogenates. Major constituents of essential oil identified by gas chromatography and mass spectrometry (GCMS) were beta-sesquiphellandrene (38.69%), alpha-curcumene (18.44%) and p-mentha-1,4 (8)-diene (16.29%). Atomic absorption spectroscopy (AAS) was used for the quantitative estimation of Calcium (Ca), Magnesium (Mg), Iron (Fe), Copper (Cu), Zinc (Zn), Chromium (Cr), Nickel (Ni) and Manganese (Mn). The extract showed highest Mg (49.4 mg/l) concentration followed by Ca (35.42 mg/l) and Fe (1.27 mg/l). Our data revealed that the ethanolic extract of Curcuma Longa at 1-10 mg/kg significantly inhibited TBARS production in all tested homogenates. Crude extracts and essential oil were tested against three gram positive bacteria i.e. Bacillus subtilis, Bacillus atrophoeus, Staphylococcus aureus, six gram negative bacteria i.e. Escherichia coli, Klebsiella pneumonias, Salmonella typhi, Pseudomonas aeruginosa, Erwinia carotovora, Agrobacterium tumefaciens and one fungal strain namely Candida albicans by disc diffusion assay. Essential oil showed highest anti-microbial activity as compared to the crude extracts. The present study confirms the significant antimicrobial and antioxidant potential of the studied plant, which can be considered as a diet supplement for a variety of oxidative stress induced or infectious diseases.

  19. Growth phase-dependent regulation and stringent control of fis are conserved processes in enteric bacteria and involve a single promoter (fis P) in Escherichia coli.

    Science.gov (United States)

    Mallik, Prabhat; Pratt, Timothy S; Beach, Michael B; Bradley, Meranda D; Undamatla, Jayanthi; Osuna, Robert

    2004-01-01

    The intracellular concentration of the Escherichia coli factor for inversion stimulation (Fis), a global regulator of transcription and a facilitator of certain site-specific DNA recombination events, varies substantially in response to changes in the nutritional environment and growth phase. Under conditions of nutritional upshift, fis is transiently expressed at very high levels, whereas under induced starvation conditions, fis is repressed by stringent control. We show that both of these regulatory processes operate on the chromosomal fis genes of the enterobacteria Klebsiella pneumoniae, Serratia marcescens, Erwinia carotovora, and Proteus vulgaris, strongly suggesting that the physiological role of Fis is closely tied to its transcriptional regulation in response to the nutritional environment. These transcriptional regulatory processes were previously shown to involve a single promoter (fis P) preceding the fis operon in E. coli. Recent work challenged this notion by presenting evidence from primer extension assays which appeared to indicate that there are multiple promoters upstream of fis P that contribute significantly to the expression and regulation of fis in E. coli. Thus, a rigorous analysis of the fis promoter region was conducted to assess the contribution of such additional promoters. However, our data from primer extension analysis, S1 nuclease mapping, beta-galactosidase assays, and in vitro transcription analysis all indicate that fis P is the sole E. coli fis promoter in vivo and in vitro. We further show how certain conditions used in the primer extension reactions can generate artifacts resulting from secondary annealing events that are the likely source of incorrect assignment of additional fis promoters.

  20. MICROORGANISMOS BENÉFICOS EN EL CONTROL DE ENFERMEDADES EN JENGIBRE

    Directory of Open Access Journals (Sweden)

    Marena Chavarría

    2005-01-01

    Full Text Available En Peñas Blanca, San Ramón de Alajuela, se evaluó la acción supresora de las cepas de Trichoderma viride 2C-PR, Bacillus subtilis 002R y Streptomyces griseus 001, en el combate de Fusarium solani, Rhizoctonia solani, Pseudomonas sp y Erwinia carotovora, en plantas de jengibre, en comparación con fungicidas y bactericidas usados por el agricultor. Las aplicaciones se realizaron cada 15 días durante un periodo de 9 meses y cada semana cuando se presentó algún foco de infección. La duración del trabajo fue de 11 meses (febrero-diciembre. Se evaluó la sobrevivencia de los patógenos y los biocontroladores, para lo cual se realizaron análisis microbiológicos a los 4 y 9 meses de edad de cultivo; se evaluó además producción. En términos generales, se observó una tendencia a la disminución del inóculo de los patógenos en el tratamiento biológico, en comparación con el tratamiento químico en ambos muestreos, a excepción de F. solani en el primer muestreo. Al final del ensayo se pudo determinar la presencia de la cepa de Trichoderma con poblaciones de 4,5x108 conidios g-1, Bacillus con 6,1x1010 UFC ml-1 y Streptomyces fue la cepa que menos persistió en el campo, con una poblacion 2x101 ml-1.

  1. MICROBIOLOGICAL QUALITY ASSESSMENT OF DRIED YAM CHIPS (Dioscorea rotundata DURING STORAGE

    Directory of Open Access Journals (Sweden)

    Patricia F. Omojasola

    2013-12-01

    Full Text Available Microbiological and physico-chemical analyses of dried yam chips (gbodo retailed in four markets in Ilorin and its environs alongside a laboratory – prepared control were carried out over a six month period. Microbiological assay consisted of total viable and coliform counts as well as microbial isolation. A total of 11 fungi and 5 bacteria were isolated from the different samples which included Acremonium sp., Aspergillus fumigatus., A. niger, A. ochraceus, Fusarium solani, Mucor hiemalis, Mucor racemosus, Penicillum notatum, Rhizopus oryzae, Rhizopus stolonifer, Syncephalastrum racemosum and Bacillus cereus, Bacillus subtilis, Erwinia carotovora, Escherichia coli and Staphylococcus aureus respectively. Total Viable Counts ranged from 3.0-120.0 cfu g-1 and coliform counts ranged from 0.00 - 18.80 cfu g-1 pre-storage to 0.10-219 cfu g-1 and 0.0-31.0 cfu g-1 post storage respectively. The physico-chemical parameters analysed were moisture content which ranged between 14.38-17.10% pre-storage to 13.43-24.96% post-storage; crude protein: 5.81-7.53% and 2.11-6.75%; crude fat: 0.35-0.71% and 0.07-0.61%; ash content: 3.30-5.18% and 1.17-4.77%; crude fibre: 0.77-1.45%; carbohydrate: 70.18-74.00% and 70.93-75.17% pre-storage and post-storage content respectively. Levels of Aflatoxin B1 were also monitored throughout the storage period. Insect infestation of the samples occurred during the storage period. Four species were identified; these were Tribolium casteneum, Dinoderus porcellus, Rhyzopertha dominica and Sitophilus zeamais. The traditional practice of open air sun-drying of yam chips should be discouraged, rather oven drying is recommended to minmize microbial contamination. In addition, sorting to exclude extreneous material and minimize mouldiness and insect infestation is suggested.

  2. Wolbachia-mediated antibacterial protection and immune gene regulation in Drosophila.

    Directory of Open Access Journals (Sweden)

    Zhee Sheen Wong

    Full Text Available The outcome of microbial infection of insects is dependent not only on interactions between the host and pathogen, but also on the interactions between microbes that co-infect the host. Recently the maternally inherited endosymbiotic bacteria Wolbachia has been shown to protect insects from a range of microbial and eukaryotic pathogens. Mosquitoes experimentally infected with Wolbachia have upregulated immune responses and are protected from a number of pathogens including viruses, bacteria, Plasmodium and filarial nematodes. It has been hypothesised that immune upregulation underpins Wolbachia-mediated protection. Drosophila is a strong model for understanding host-Wolbachia-pathogen interactions. Wolbachia-mediated antiviral protection in Drosophila has been demonstrated for a number of different Wolbachia strains. In this study we investigate whether Wolbachia-infected flies are also protected against pathogenic bacteria. Drosophila simulans lines infected with five different Wolbachia strains were challenged with the pathogenic bacteria Pseudomonas aeruginosa PA01, Serratia marcescens and Erwinia carotovora and mortality compared to paired lines without Wolbachia. No difference in mortality was observed in the flies with or without Wolbachia. Similarly no antibacterial protection was observed for D. melanogaster infected with Wolbachia. Interestingly, D. melanogaster Oregon RC flies which are naturally infected with Wolbachia showed no upregulation of the antibacterial immune genes TepIV, Defensin, Diptericin B, PGRP-SD, Cecropin A1 and Attacin D compared to paired flies without Wolbachia. Taken together these results indicate that Wolbachia-mediated antibacterial protection is not ubiquitous in insects and furthermore that the mechanisms of antibacterial and antiviral protection are independent. We suggest that the immune priming and antibacterial protection observed in Wolbachia-infected mosquitoes may be a consequence of the recent

  3. Signal Integration in Quorum Sensing Enables Cross-Species Induction of Virulence in Pectobacterium wasabiae

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    Rita S. Valente

    2017-05-01

    Full Text Available Bacterial communities can sense their neighbors, regulating group behaviors in response to cell density and environmental changes. The diversity of signaling networks in a single species has been postulated to allow custom responses to different stimuli; however, little is known about how multiple signals are integrated and the implications of this integration in different ecological contexts. In the plant pathogen Pectobacterium wasabiae (formerly Erwinia carotovora, two signaling networks—the N-acyl homoserine lactone (AHL quorum-sensing system and the Gac/Rsm signal transduction pathway—control the expression of secreted plant cell wall-degrading enzymes, its major virulence determinants. We show that the AHL system controls the Gac/Rsm system by affecting the expression of the regulatory RNA RsmB. This regulation is mediated by ExpR2, the quorum-sensing receptor that responds to the P. wasabiae cognate AHL but also to AHLs produced by other bacterial species. As a consequence, this level of regulation allows P. wasabiae to bypass the Gac-dependent regulation of RsmB in the presence of exogenous AHLs or AHL-producing bacteria. We provide in vivo evidence that this pivotal role of RsmB in signal transduction is important for the ability of P. wasabiae to induce virulence in response to other AHL-producing bacteria in multispecies plant lesions. Our results suggest that the signaling architecture in P. wasabiae was coopted to prime the bacteria to eavesdrop on other bacteria and quickly join the efforts of other species, which are already exploiting host resources.

  4. Perspectives de lutte contre les maladies des arbres fruitiers à pépins au moyen de substances naturelles inductrices d'une résistance systémique

    Directory of Open Access Journals (Sweden)

    Lateur M.

    2002-01-01

    Full Text Available Natural compounds used as elicitors of systemic induced resistance offer new prospects to control pome fruit tree diseases. This review presents a new way of plant protection for pome fruit tree diseases as a potential response to the very high use of pesticides in commercial production with the view to reduce their negative side-effects on environment and human health. Work is focused on examples of use of elicitors from natural origin which induce systemic resistance for controlling two important diseases as apple scab (Venturia inaequalis and fire blight (Erwinia amylovora. Many factors limit today their practical use: their efficacy is only partial and in interaction with plants and environment; much work has to be done to improve the formulation and to determine doses and rates of application, the right phenologic application times, and finally they are often submitted to the normal high standards of Plant Protection Products Regulations which are long, very expensive and not adapted to compounds which can have a very complex composition. In other hands, this new way of plant protection presents many potential advantages: using relatively simple, not expensive, non toxic natural compounds with a good image; polyvalent and broad field of action; non-specific and multi-side action which offer a good durability of action; systemic action in the plants during a relative long period of time and the possibility to control difficult bacterial diseases and more surprisingly viral diseases. The multiple advantages presented offer valuable prospects for a better friend-environmentally way to control pome fruit diseases in the next future.

  5. Membrane-targeted HrpNEa can modulate apple defense gene expression.

    Science.gov (United States)

    Vergne, E; de Bernonville, T Dugé; Dupuis, F; Sourice, S; Cournol, R; Berthelot, P; Barny, M A; Brisset, M N; Chevreau, E

    2014-02-01

    Fire blight caused by Erwinia amylovora is the major bacterial disease of tribe Maleae, including apple. Among the proteins secreted by this bacterium, HrpNEa, also called harpin, is known to induce hypersensitive response in nonhost plants and to form amyloid oligomers leading to pore opening in the plasma membrane and alteration of membrane homeostasis. To better understand the physiological effects of HrpNEa in the host plant, we produced transgenic apple plants expressing HrpNEa with or without a secretion signal peptide (SP). HrpNEa expressed with a SP was found to be associated within the membrane fraction, in accordance with amyloidogenic properties and the presence of transmembrane domains revealed by in silico analysis. Expression analysis of 28 apple defense-related genes revealed gene modulations in the transgenic line expressing membrane-targeted HrpNEa. While apple transgenic trees displaying a high constitutive expression level of SP-HrpNEa showed a slight reduction of infection frequency after E. amylovora inoculation, there was no decrease in the disease severity. Thus HrpNEa seems to act as an elicitor of host defenses, when localized in the host membrane.

  6. Ectopic Expression of Hrf1 Enhances Bacterial Resistance via Regulation of Diterpene Phytoalexins, Silicon and Reactive Oxygen Species Burst in Rice

    Science.gov (United States)

    Zhong, Weigong; Yang, Jie; Okada, Kazunori; Yamane, Hisakazu; Zhang, Lei; Wang, Guang; Wang, Dong; Xiao, Shanshan; Chang, Shanshan; Qian, Guoliang; Liu, Fengquan

    2012-01-01

    Harpin proteins as elicitor derived from plant gram negative bacteria such as Xanthomonas oryzae pv. oryzae (Xoo), Erwinia amylovora induce disease resistance in plants by activating multiple defense responses. However, it is unclear whether phytoalexin production and ROS burst are involved in the disease resistance conferred by the expression of the harpinXoo protein in rice. In this article, ectopic expression of hrf1 in rice enhanced resistance to bacterial blight. Accompanying with the activation of genes related to the phytoalexin biosynthesis pathway in hrf1-transformed rice, phytoalexins quickly and consistently accumulated concurrent with the limitation of bacterial growth rate. Moreover, the hrf1-transformed rice showed an increased ability for ROS scavenging and decreased hydrogen peroxide (H2O2) concentration. Furthermore, the localization and relative quantification of silicon deposition in rice leaves was detected by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Finally, the transcript levels of defense response genes increased in transformed rice. These results show a correlation between Xoo resistance and phytoalexin production, H2O2, silicon deposition and defense gene expression in hrf1-transformed rice. These data are significant because they provide evidence for a better understanding the role of defense responses in the incompatible interaction between bacterial disease and hrf1-transformed plants. These data also supply an opportunity for generating nonspecific resistance to pathogens. PMID:22970151

  7. Ectopic expression of Hrf1 enhances bacterial resistance via regulation of diterpene phytoalexins, silicon and reactive oxygen species burst in rice.

    Directory of Open Access Journals (Sweden)

    Wenqi Li

    Full Text Available Harpin proteins as elicitor derived from plant gram negative bacteria such as Xanthomonas oryzae pv. oryzae (Xoo, Erwinia amylovora induce disease resistance in plants by activating multiple defense responses. However, it is unclear whether phytoalexin production and ROS burst are involved in the disease resistance conferred by the expression of the harpin(Xoo protein in rice. In this article, ectopic expression of hrf1 in rice enhanced resistance to bacterial blight. Accompanying with the activation of genes related to the phytoalexin biosynthesis pathway in hrf1-transformed rice, phytoalexins quickly and consistently accumulated concurrent with the limitation of bacterial growth rate. Moreover, the hrf1-transformed rice showed an increased ability for ROS scavenging and decreased hydrogen peroxide (H(2O(2 concentration. Furthermore, the localization and relative quantification of silicon deposition in rice leaves was detected by scanning electron microscopy (SEM and energy-dispersive X-ray spectrometer (EDS. Finally, the transcript levels of defense response genes increased in transformed rice. These results show a correlation between Xoo resistance and phytoalexin production, H(2O(2, silicon deposition and defense gene expression in hrf1-transformed rice. These data are significant because they provide evidence for a better understanding the role of defense responses in the incompatible interaction between bacterial disease and hrf1-transformed plants. These data also supply an opportunity for generating nonspecific resistance to pathogens.

  8. Ectopic expression of Hrf1 enhances bacterial resistance via regulation of diterpene phytoalexins, silicon and reactive oxygen species burst in rice.

    Science.gov (United States)

    Li, Wenqi; Shao, Min; Zhong, Weigong; Yang, Jie; Okada, Kazunori; Yamane, Hisakazu; Zhang, Lei; Wang, Guang; Wang, Dong; Xiao, Shanshan; Chang, Shanshan; Qian, Guoliang; Liu, Fengquan

    2012-01-01

    Harpin proteins as elicitor derived from plant gram negative bacteria such as Xanthomonas oryzae pv. oryzae (Xoo), Erwinia amylovora induce disease resistance in plants by activating multiple defense responses. However, it is unclear whether phytoalexin production and ROS burst are involved in the disease resistance conferred by the expression of the harpin(Xoo) protein in rice. In this article, ectopic expression of hrf1 in rice enhanced resistance to bacterial blight. Accompanying with the activation of genes related to the phytoalexin biosynthesis pathway in hrf1-transformed rice, phytoalexins quickly and consistently accumulated concurrent with the limitation of bacterial growth rate. Moreover, the hrf1-transformed rice showed an increased ability for ROS scavenging and decreased hydrogen peroxide (H(2)O(2)) concentration. Furthermore, the localization and relative quantification of silicon deposition in rice leaves was detected by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Finally, the transcript levels of defense response genes increased in transformed rice. These results show a correlation between Xoo resistance and phytoalexin production, H(2)O(2), silicon deposition and defense gene expression in hrf1-transformed rice. These data are significant because they provide evidence for a better understanding the role of defense responses in the incompatible interaction between bacterial disease and hrf1-transformed plants. These data also supply an opportunity for generating nonspecific resistance to pathogens.

  9. The influence of carbon source and calcium on the production of ...

    African Journals Online (AJOL)

    use

    2011-12-10

    Dec 10, 2011 ... showed in vitro degradation of potato lectins by a pro- tease produced from the potato pathogen, E. carotovora. Marits et al. (1999) isolated a mutant of E. carotovora that produced normal levels of pectate lyase, polygalac- turonase and cellulase but was deficient in extracellular protease production.

  10. Activation of the pathogen-inducible Gst1 promoter of potato after elicitation by Venturia inaequalis and Erwinia amylovora in transgenic apple (Malus x domestica).

    Science.gov (United States)

    Malnoy, M; Reynoird, J P; Borejsza-Wysocka, E E; Aldwinckle, H S

    2006-02-01

    Rather than using a constitutive promoter to drive transgenes for resistance against fungal and bacterial diseases in genetic engineering of apple (Malus x domestica) cultivars, a promoter induced only after infection was preferred. The ability of the Pgst1 promoter from potato (Solanum tuberosum L.) to drive expression of the gusA reporter gene was determined in two genotypes of apple: the fruit cultivar Royal Gala and the M.26 rootstock. beta-Glucuronidase activity in the transgenic lines grown in a growth chamber was determined quantitatively using fluorometric assays and compared to the activity in Cauliflower Mosaic Virus (CaMV) 35S promoter-driven transgenic lines. In both apple genotypes, the Pgst1 promoter exhibited a low level of expression after bacterial and fungal inoculation compared to the level obtained with the PCaMV35S promoter (15% and 8% respectively). The Pgst1 promoter was systematically activated in apple at the site of infection with a fungal pathogen. It was also activated after treatment with salicylic acid, but not after wounding. Taken together, these data show that, although the Pgst1 promoter is less active than the PCaMV35S promoter in apple, its pathogen responsiveness could be useful in driving the expression of transgenes to promote bacterial and fungal disease resistance.

  11. Diverse responses of tanshinone biosynthesis to biotic and abiotic elicitors in hairy root cultures of Salvia miltiorrhiza and Salvia castanea Diels f. tomentosa.

    Science.gov (United States)

    Yang, Dongfeng; Fang, Yumin; Xia, Pengguo; Zhang, Xiaodan; Liang, Zongsuo

    2017-11-28

    Salvia miltiorrhiza (S. miltiorrhiza) and Salvia castanea Diels f. tomentosa (S. castanea) are both used for treatment of cardiovascular diseases. They have the same bioactive compound tanshinones, but whose contents are hugely different. This study illustrated diverse responses of tanshinone biosynthesis to yeast extract (YE) and Ag+ in hairy roots of the two species. YE enhanced both the growth and tanshinone biosynthesis of two hairy roots, and contributed more to tanshinone accumulation in S. castanea than that in S. miltiorrhiza. Genes encoding 1-deoxy-d-xylulose 5-phosphate synthase (DXS2), geranylgeranyl diphosphatesynthase (GGPPS1), copalyl diphosphate synthase (CPS1), and two cytochromes P450 (CYP76AH1 and CYP76AH3) were also more responsive to YE in S. castanea than those in S. miltiorrhiza. Accumulations of dihydrotanshinone I and tanshinone I, and most biosynthetic genes in S. miltiorrhiza were more responsive to Ag+ than those in S. castanea. Accumulations of dihydrotanshinone I and cryptotanshinone were more responsive to YE, while tanshinone IIA accumulation was more responsive to Ag+ in S. miltiorrhiza. However, accumulations of other four tanshinones and related genes in S. castanea were more responsive to YE than Ag+. This study provides foundations for studying diverse specialized metabolism between the related species. Copyright © 2017. Published by Elsevier B.V.

  12. 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.

  13. Elicitor-Induced Association of Isoflavone O-Methyltransferase with Endomembranes Prevents the Formation and 7-O-Methylation of Daidzein during Isoflavonoid Phytoalexin Biosynthesis

    Science.gov (United States)

    Liu, Chang-Jun; Dixon, Richard A.

    2001-01-01

    The bioactive isoflavonoids of the Leguminosae often are methylated on the 4′-position of their B-rings. Paradoxically, reverse genetic evidence implicates alfalfa isoflavone O-methyltransferase (IOMT) in the biosynthesis of 4′-O-methylated isoflavonoids such as the phytoalexin medicarpin in vivo, whereas biochemical studies indicate that IOMT has strict specificity for methylation of the A-ring 7-hydroxyl of daidzein, the presumed substrate for O-methylation, in vitro. Radiolabeling and isotope dilution studies now confirm that daidzein is not an intermediate in isoflavonoid phytoalexin biosynthesis in alfalfa. Furthermore, protein gel blot analysis and confocal microscopy of a transiently expressed IOMT–green fluorescent protein fusion in alfalfa leaves show that the operationally soluble IOMT localizes to endomembranes after elicitation of the isoflavonoid pathway. We propose that IOMT colocalizes with the endoplasmic reticulum–associated isoflavone synthase cytochrome P450 to ensure rapid B-ring methylation of the unstable 2,4′,7-trihydroxyisoflavanone product of isoflavone synthase, thereby preventing its dehydration to daidzein and subsequent A-ring methylation by free IOMT. In this way, metabolic channeling at the entry point into isoflavonoid phytoalexin biosynthesis protects an unstable intermediate from an unproductive metabolic conversion. PMID:11752378

  14. Overexpression of the PeaT1 Elicitor Gene from Alternaria tenuissima Improves Drought Tolerance in Rice Plants via Interaction with a Myo-Inositol Oxygenase

    Directory of Open Access Journals (Sweden)

    Fachao Shi

    2017-06-01

    Full Text Available Abiotic stresses, especially drought, seriously threaten cereal crops yields and quality. In this study, we observed that the rice plants of overexpression the Alternariatenuissima PeaT1 gene showed enhanced drought stress tolerance and increased the survival rate following a drought treatment. In PeaT1-overexpressing (PeaT1OE plants, abscisic acid and chlorophyll content significantly increased, while the malondialdehyde (MDA content decreased compared with the wild-type plants. Additionally, we confirmed that the transcript levels of drought-responsive genes, including OsAM1, OsLP2, and OsDST, were prominently lower in the PeaT1OE plants. In contrast, expression levels of genes encoding positive drought stress regulators including OsSKIPa, OsCPK9, OsNAC9, OSEREBP1, and OsTPKb were upregulated in PeaT1OE plants. Furthermore, combing the yeast two-hybrid assay, we found that PeaT1 could interact with amyo-inositol oxygenase (OsMIOX, which was verified by pull-down assay. Interestingly, OsMIOX was highly expressed in PeaT1OE plants during the drought treatment. Additionally, the OsMIOX-GFP fusion protein co-localized with the endoplasmic reticulum (ER marker in tobacco protoplasts, suggesting OsMIOX performs its function in ER. Therefore, our results are useful for elucidating the molecular mechanism underlying the improvement of drought tolerance by PeaT1.

  15. Genome analysis of poplar LRR-RLP gene clusters reveals RISP, a defense-related gene coding a candidate endogenous peptide elicitor

    Directory of Open Access Journals (Sweden)

    Benjamin ePetre

    2014-03-01

    Full Text Available In plants, cell-surface receptors control immunity and development through the recognition of extracellular ligands. Leucine-rich repeat receptor-like proteins (LRR-RLPs constitute a large multigene family of cell-surface receptors. Although this family has been intensively studied, a limited number of ligands has been identified so far, mostly because methods used for their identification and characterisation are complex and fastidious. In this study, we combined genome and transcriptome analyses to describe the LRR-RLP gene family in the model tree poplar (Populus trichocarpa. In total, 82 LRR-RLP genes have been identified in P. trichocarpa genome, among which 66 are organised in clusters of up to seven members. In these clusters, LRR-RLP genes are interspersed by orphan, poplar-specific genes encoding small proteins of unknown function (SPUFs. In particular, the nine largest clusters of LRR-RLP genes (47 LRR-RLPs include 71 SPUF genes that account for 59% of the non-LRR-RLP gene content within these clusters. Forty-four LRR-RLP and fifty-five SPUF genes are expressed in poplar leaves, mostly at low levels, except for members of some clusters that show higher and sometimes coordinated expression levels. Notably, wounding of poplar leaves strongly induced the expression of a defense SPUF gene named Rust-Induced Secreted protein (RISP that has been previously reported as a marker of poplar defense responses. Interestingly, we show that the RISP-associated LRR-RLP gene is highly expressed in poplar leaves and slightly induced by wounding. Both gene promoters share a highly conserved region of approx. 300 nucleotides. This led us to hypothesize that the corresponding pair of proteins could be involved in poplar immunity, possibly as a ligand/receptor couple.In conclusion, we speculate that some poplar SPUFs, such as RISP, represent candidate endogenous peptide ligands of the associated LRR-RLPs and we discuss how to investigate further this hypothesis.

  16. Synergistic effects of plant defense elicitors and Trichoderma harzianum on enhanced induction of antioxidant defense system in tomato against Fusarium wilt disease

    OpenAIRE

    Zehra, Andleeb; Meena, Mukesh; Dubey, Manish Kumar; Aamir, Mohd; Upadhyay, R. S.

    2017-01-01

    Plant defense against their pathogens can be induced by a complex network of different inducers. The present study investigates the synergistic effect of Trichoderma harzianum, exogenous salicylic acid (SA) and methyl jasmonate (MeJA) over the response and regulation of the antioxidant defense mechanisms and lipid peroxidation in tomato plants against Fusarium wilt disease. In the present work, tomato plants were infected by Fusarium oxysporum f. sp. lycopersici 3 days after inoculated with T...

  17. A Novel WRKY transcription factor is required for induction of PR-1a gene expression by salicylic acid and bacterial elicitors

    NARCIS (Netherlands)

    van Verk, Marcel C|info:eu-repo/dai/nl/327618671; Pappaioannou, Dimitri; Neeleman, Lyda; Bol, John F; Linthorst, Huub J M

    PR-1a is a salicylic acid-inducible defense gene of tobacco (Nicotiana tabacum). One-hybrid screens identified a novel tobacco WRKY transcription factor (NtWRKY12) with specific binding sites in the PR-1a promoter at positions -564 (box WK(1)) and -859 (box WK(2)). NtWRKY12 belongs to the class of

  18. Microorganisms associated with post-harvest green olives deteriorations in Morocco

    Directory of Open Access Journals (Sweden)

    Faid, M.

    1994-10-01

    -negativa estuvieron representadas por las especies: Erwinia carotovora, Hafnia alvei, Enterobacter agglomerans, E. aerogenes y Serratia marcescens, S. liquefaciens y Shigella flexneri. Las bacterias oxidasa- positiva fueron las más abundantes, predominando las especies de Pseudomonas, P. aeruginosa, P. alcaligenes y P. Syringae. La mayoría de los aislados de estos microorganismos fueron celulolíticos y lipolíticos. Las especies bacillus fueron también aisladas e identificadas. Las especies principales fueron Bacillus megaterium, B. pumilus, B. cereus y B. olei. Las especies de bacillus no parecieron estar relacionadas con la deterioración de las aceitunas.

  19. Antimicrobial activity of some macrophytes from Lake Manzalah (Egypt).

    Science.gov (United States)

    Fareed, M F; Haroon, A M; Rabeh, S A

    2008-11-01

    The antimicrobial activities of aqueous and organic solvents (chloroform, ethanol and methanol) extracts of four plants Ceratophyllum demersum L., Eichhornia crassipes, Potamogeton crispus and Potamogeton pectinatus were tested in vitro against seventeen different microorganisms including Gram-positive and Gram-negative bacteria and fungi. Nine of these identified organisms were obtained from different sources, Bacillus subtilis 1020, Bacillus cereus 1080, Staphylococcus aureus, Erwinia carotovora NCPPB 312, Candida albicans, Candida tropicalis, Aspergillus niger, Fusarium oxysporum and Penicillium italicum. The other eight organisms were isolated from Manzalah lake water and identified using API 20E strip system (BioMereux). One hundred pathogenic bacterial isolates representing eight genera were identified to species level. These organisms are Escherichia coli (20%), Pseudomonas aeruginosa (16%), Klebsiella pneumoniae (14%), Salmonella colerasuis (13%), Shigella sp. (11%), Serratia liquefaciens (10%), Proteus vulgaris (9%) and Brenneria nigrifluens (7%). The extracts of all tested plants demonstrated antimicrobial activity against the used organisms. The efficiency of the extracts varied with, solvent used in the extraction as well as plant species and the part of plant used. The aqueous extract appeared to be the highly effective extract against all tested organisms especially Fusarium oxysporum causing inhibition zone 48 +/- 0.01 mm, Pseudomonas aeruginosa 59 +/- 0.02 mm and Salmonella cholerasuis 55 +/- 0.01 mm when using P. crispus, P. pectinatus and C. demersum, respectively. Ethanol extracts of C. demersum, P. crispus and E. crassipes root showed antimicrobial activities against all tested organisms except Aspergillus niger. At the same time the extract of P. pectinatus had no effect also on Fusarium oxysporum and the extract of E. crassipes leaves have no effect on Penicillium italicum. On using chloroform extracts Escherichia coli, Aspergillus niger and

  20. Microbial Siderophores Exert a Subtle Role in Arabidopsis during Infection by Manipulating the Immune Response and the Iron Status1[W

    Science.gov (United States)

    Dellagi, Alia; Segond, Diego; Rigault, Martine; Fagard, Mathilde; Simon, Clara; Saindrenan, Patrick; Expert, Dominique

    2009-01-01

    Siderophores (ferric ion chelators) are secreted by organisms in response to iron deficiency. The pathogenic enterobacterium Erwinia chrysanthemi produces two siderophores, achromobactin and chrysobactin (CB), which are required for systemic dissemination in host plants. Previous studies have shown that CB is produced in planta and can trigger the up-regulation of the plant ferritin gene AtFER1. To further investigate the function of CB during pathogenesis, we analyzed its effect in Arabidopsis (Arabidopsis thaliana) plants following leaf infiltration. CB activates the salicylic acid (SA)-mediated signaling pathway, while the CB ferric complex is ineffective, suggesting that the elicitor activity of this siderophore is due to its iron-binding property. We confirmed this hypothesis by testing the effect of siderophores structurally unrelated to CB, including deferrioxamine. There was no activation of SA-dependent defense in plants grown under iron deficiency before CB treatment. Transcriptional analysis of the genes encoding the root ferrous ion transporter and ferric chelate reductase, and determination of the activity of this enzyme in response to CB or deferrioxamine, showed that these compounds induce a leaf-to-root iron deficiency signal. This root response as well as ferritin gene up-regulation in the leaf were not compromised in a SA-deficient mutant line. Using the Arabidopsis-E. chrysanthemi pathosystem, we have shown that CB promotes bacterial growth in planta and can modulate plant defenses through an antagonistic mechanism between SA and jasmonic acid signaling cascades. Collectively, these data reveal a new link between two processes mediated by SA and iron in response to microbial siderophores. PMID:19448037

  1. Microbial siderophores exert a subtle role in Arabidopsis during infection by manipulating the immune response and the iron status.

    Science.gov (United States)

    Dellagi, Alia; Segond, Diego; Rigault, Martine; Fagard, Mathilde; Simon, Clara; Saindrenan, Patrick; Expert, Dominique

    2009-08-01

    Siderophores (ferric ion chelators) are secreted by organisms in response to iron deficiency. The pathogenic enterobacterium Erwinia chrysanthemi produces two siderophores, achromobactin and chrysobactin (CB), which are required for systemic dissemination in host plants. Previous studies have shown that CB is produced in planta and can trigger the up-regulation of the plant ferritin gene AtFER1. To further investigate the function of CB during pathogenesis, we analyzed its effect in Arabidopsis (Arabidopsis thaliana) plants following leaf infiltration. CB activates the salicylic acid (SA)-mediated signaling pathway, while the CB ferric complex is ineffective, suggesting that the elicitor activity of this siderophore is due to its iron-binding property. We confirmed this hypothesis by testing the effect of siderophores structurally unrelated to CB, including deferrioxamine. There was no activation of SA-dependent defense in plants grown under iron deficiency before CB treatment. Transcriptional analysis of the genes encoding the root ferrous ion transporter and ferric chelate reductase, and determination of the activity of this enzyme in response to CB or deferrioxamine, showed that these compounds induce a leaf-to-root iron deficiency signal. This root response as well as ferritin gene up-regulation in the leaf were not compromised in a SA-deficient mutant line. Using the Arabidopsis-E. chrysanthemi pathosystem, we have shown that CB promotes bacterial growth in planta and can modulate plant defenses through an antagonistic mechanism between SA and jasmonic acid signaling cascades. Collectively, these data reveal a new link between two processes mediated by SA and iron in response to microbial siderophores.

  2. Gclust Server: 43629 [Gclust Server

    Lifescience Database Archive (English)

    Full Text Available Cluster Sequences Related Sequences(104) 379 immediate-early fungal elicitor family protein 2 1.00e-12...Sequence length 379 Representative annotation immediate-early fungal elicitor family protein Number of

  3. Elicitation of Valerenic Acid in the Hairy Root Cultures of Valeriana ...

    African Journals Online (AJOL)

    simulate pathogen-induced plant defense responses. Successful induction of valepotriate has been reported in adventitious roots of. Valeriana amurensis by biotic and abiotic elicitors. [15]. The effect of elicitors depends on several parameters such as elicitor concentration, age of culture at the time of elicitation, cell line and.

  4. The Pseudomonas aeruginosa oxyvinylglycine L-2-amino-4-methoxy-trans-3-butenoic acid inhibits growth of Erwinia amylovora and acts as a weak seed germination-arrest factor

    Science.gov (United States)

    The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) is demonstrated to share biological activities with 4-formylaminooxyvinylglycine, a related molecule produced by Pseudomonas fluorescens WH6. We found that culture filtrates of a P. aeruginosa strain overproduc...

  5. Sm2, a paralog of the Trichoderma cerato-platanin elicitor Sm1, is also highly important for plant protection conferred by the fungal-root interaction of Trichoderma with maize.

    Science.gov (United States)

    Gaderer, Romana; Lamdan, Netta L; Frischmann, Alexa; Sulyok, Michael; Krska, Rudolf; Horwitz, Benjamin A; Seidl-Seiboth, Verena

    2015-01-16

    The proteins Sm1 and Sm2 from the biocontrol fungus Trichoderma virens belong to the cerato-platanin protein family. Members of this family are small, secreted proteins that are abundantly produced by filamentous fungi with all types of life-styles. Some species of the fungal genus Trichoderma are considered as biocontrol fungi because they are mycoparasites and are also able to directly interact with plants, thereby stimulating plant defense responses. It was previously shown that the cerato-platanin protein Sm1 from T. virens - and to a lesser extent its homologue Epl1 from Trichoderma atroviride - induce plant defense responses. The plant protection potential of other members of the cerato-platanin protein family in Trichoderma, however, has not yet been investigated. In order to analyze the function of the cerato-platanin protein Sm2, sm1 and sm2 knockout strains were generated and characterized. The effect of the lack of Sm1 and Sm2 in T. virens on inducing systemic resistance in maize seedlings, challenged with the plant pathogen Cochliobolus heterostrophus, was tested. These plant experiments were also performed with T. atroviride epl1 and epl2 knockout strains. In our plant-pathogen system T. virens was a more effective plant protectant than T. atroviride and the results with both Trichoderma species showed concordantly that the level of plant protection was more strongly reduced in plants treated with the sm2/epl2 knockout strains than with sm1/epl1 knockout strains. Although the cerato-platanin genes sm1/epl1 are more abundantly expressed than sm2/epl2 during fungal growth, Sm2/Epl2 are, interestingly, more important than Sm1/Epl1 for the promotion of plant protection conferred by Trichoderma in the maize-C. heterostrophus pathosystem.

  6. In roots of Arabidopsis thaliana, the damage-associated molecular pattern AtPep1 is a stronger elicitor of immune signalling than flg22 or the chitin heptamer

    OpenAIRE

    Poncini, Lorenzo; Wyrsch, Ines; Tendon, Valérie Dénervaud; Vorley, Thomas; Boller, Thomas; Geldner, Niko; Métraux, Jean-Pierre; Lehmann, Silke

    2017-01-01

    Plants interpret their immediate environment through perception of small molecules. Microbe-associated molecular patterns (MAMPs) such as flagellin and chitin are likely to be more abundant in the rhizosphere than plant-derived damage-associated molecular patterns (DAMPs). We investigated how the Arabidopsis thaliana root interprets MAMPs and DAMPs as danger signals. We monitored root development during exposure to increasing concentrations of the MAMPs flg22 and the chitin heptamer as ...

  7. Cell Surfaces in Plant-Microorganism Interactions 1

    Science.gov (United States)

    Roby, Dominique; Toppan, Alain; Esquerré-Tugayé, Marie-Thérèse

    1985-01-01

    Treatment of melon hypocotyls or petioles with an elicitor from Colletotrichum lagenarium, a fungal pathogen of melons, causes an initial transitory inhibition of protein synthesis and, after 18 hours, induces the synthesis of a plant cell wall hydroxyproline-rich glycoprotein (HRGP). Microgram amounts of elicitor are sufficient for maximum elicitation of HRGP when the elicitor is injected into hypocotyls. High elicitor concentrations have a strong inhibitory effect on total protein synthesis. Ethylene is increased early in elicitor-treated plant material, and may be involved in HRGP elicitation. In the presence of aminoethoxyvinylglycine, an inhibitor of ethylene synthesis, both elicitor-induced ethylene and elicitor-induced HRGP are inhibited. On the other hand, 1-aminocyclopropane-1-carboxylic acid, the direct precursor of ethylene, triggers the synthesis of HRGP to the same extent as the elicitor of C. lagenarium, and partly restores in elicitor-treated petioles the synthesis of ethylene and of HRGP after previous inhibition by aminoethoxyvinylglycine. Elicitation of HRGP occurs in other systems, such as soybeans when inoculated with an elicitor from Phytophtora megasperma f. sp. glycinea, and when melons are incubated with an elicitor isolated from their cell walls. PMID:16664121

  8. Bacterierot in sedum : hoe te handelen?

    NARCIS (Netherlands)

    Helm, van der F.P.M.

    2009-01-01

    In sedum kan een bacterieziekte voorkomen die zich bij nat weer zeer snel door het gewas verspreidt. De vermoedelijke veroorzaker is Erwinia chrysanthemi (Dickeya). De bacteriën zijn niet met chemische middelen te bestrijden. Door onderzoek bij PPO naar Erwinia in bolgewassen is al veel bekend over

  9. Draft Genomes, Phylogenetic Reconstruction, and Comparative Genomics of Two Novel Cohabiting Bacterial Symbionts Isolated from Frankliniella occidentalis.

    Science.gov (United States)

    Facey, Paul D; Méric, Guillaume; Hitchings, Matthew D; Pachebat, Justin A; Hegarty, Matt J; Chen, Xiaorui; Morgan, Laura V A; Hoeppner, James E; Whitten, Miranda M A; Kirk, William D J; Dyson, Paul J; Sheppard, Sam K; Del Sol, Ricardo

    2015-07-15

    Obligate bacterial symbionts are widespread in many invertebrates, where they are often confined to specialized host cells and are transmitted directly from mother to progeny. Increasing numbers of these bacteria are being characterized but questions remain about their population structure and evolution. Here we take a comparative genomics approach to investigate two prominent bacterial symbionts (BFo1 and BFo2) isolated from geographically separated populations of western flower thrips, Frankliniella occidentalis. Our multifaceted approach to classifying these symbionts includes concatenated multilocus sequence analysis (MLSA) phylogenies, ribosomal multilocus sequence typing (rMLST), construction of whole-genome phylogenies, and in-depth genomic comparisons. We showed that the BFo1 genome clusters more closely to species in the genus Erwinia, and is a putative close relative to Erwinia aphidicola. BFo1 is also likely to have shared a common ancestor with Erwinia pyrifoliae/Erwinia amylovora and the nonpathogenic Erwinia tasmaniensis and genetic traits similar to Erwinia billingiae. The BFo1 genome contained virulence factors found in the genus Erwinia but represented a divergent lineage. In contrast, we showed that BFo2 belongs within the Enterobacteriales but does not group closely with any currently known bacterial species. Concatenated MLSA phylogenies indicate that it may have shared a common ancestor to the Erwinia and Pantoea genera, and based on the clustering of rMLST genes, it was most closely related to Pantoea ananatis but represented a divergent lineage. We reconstructed a core genome of a putative common ancestor of Erwinia and Pantoea and compared this with the genomes of BFo bacteria. BFo2 possessed none of the virulence determinants that were omnipresent in the Erwinia and Pantoea genera. Taken together, these data are consistent with BFo2 representing a highly novel species that maybe related to known Pantoea. © The Author(s) 2015. Published by

  10. Dicty_cDB: AFO308 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available O04336 ELICITOR RESPONSE ELEMENT BINDING PROTEIN WRKY3 ISOLOG. ;, mRNA sequence. 48 0.12 1 BM094322 |BM094322...O04336 ELICITOR RESPONSE ELEMENT BINDING PROTEIN WRKY3 ISOLOG. ;, mRNA sequence. 48 0.12 1 AI973570 |AI973570...O04336 ELICITOR RESPONSE ELEMENT BINDING PROTEIN WRKY3 ISOLOG. ;, mRNA sequence. 48 0.12 1 AL627234 |AL627234

  11. Reflex control of the human inner ear: a half-octave offset in medial efferent feedback that is consistent with an efferent role in the control of masking.

    Science.gov (United States)

    Lilaonitkul, Watjana; Guinan, John J

    2009-03-01

    The high sensitivity and frequency selectivity of the mammalian cochlea is due to amplification produced by outer hair cells (OHCs) and controlled by medial olivocochlear (MOC) efferents. Data from animals led to the view that MOC fibers provide frequency-specific inhibitory feedback; however, these studies did not measure intact MOC reflexes. To test whether MOC inhibition is primarily at the frequency that elicits the MOC activity, acoustically elicited MOC effects were quantified in humans by the change in otoacoustic emissions produced by 60-dB SPL tone and half-octave-band noise elicitors at different frequencies relative to a 40-dB SPL, 1-kHz probe tone. On average, all elicitors produced MOC effects that were skewed (elicitor frequencies -1 octave below the probe produced larger effects than those -1 octave above). The largest MOC effects were from elicitors below the probe frequency for contra- and bilateral elicitors but were from elicitors centered at the probe frequency for ipsilateral elicitors. Typically, ipsilateral elicitors produced larger effects than contralateral elicitors and bilateral elicitors produced effects near the ipsi+contra sum. Elicitors at levels down to 30-dB SPL produced similar patterns. Tuning curves (TCs) interpolated from these data were V-shaped with Q10s approximately 2. These are sharper than MOC-fiber TCs found near 1 kHz in cats and guinea pigs. Because cochlear amplification is skewed (more below the best frequency of a cochlear region), these data are consistent with an anti-masking role of MOC efferents that reduces masking by reducing the cochlear amplification seen at 1 kHz.

  12. Dicty_cDB: SFC816 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available O04336 ELICITOR RESPONSE ELEMENT BINDING PROTEIN WRKY3 ISOLOG. ;, mRNA sequence. 48 0.17 1 BG046482 |BG046482...O04336 ELICITOR RESPONSE ELEMENT BINDING PROTEIN WRKY3 ISOLOG. ;, mRNA sequence. 48 0.17 1 dna update

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

    DEFF Research Database (Denmark)

    Aslam, Shazia N.; Erbs, Gitte; Morrissey, Kate L.

    2009-01-01

    Triggering of defences by microbes has mainly been investigated using single elicitors or microbe-associated molecular patterns (MAMPs), but MAMPs are released in planta as complex mixtures together with endogenous oligogalacturonan (OGA) elicitor. We investigated the early responses in Arabidopsis...

  14. Arabidopsis CDS blastp result: AK243317 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243317 J100056J12 At3g02840.1 68416.m00276 immediate-early fungal elicitor family... protein similar to immediate-early fungal elicitor protein CMPG1 (GI:14582200) [Petroselinum crispum] 8e-32 ...

  15. Cell Surfaces in Plant-Microorganism Interactions : IV. Fungal Glycopeptides Which Elicit the Synthesis of Ethylene in Plants.

    Science.gov (United States)

    Toppan, A; Esquerré-Tugayé, M T

    1984-08-01

    The production of ethylene by melon (Cucumis melo cv Cantaloup charentais) tissues is stimulated during incubation in the presence of fungal glycopeptides extracted from Colletotrichum lagenarium, a pathogen of melon. These glycopeptides, called elicitors of ethylene, are found in the mycelium, the cell wall, and the culture filtrate. Elicitation of ethylene is a relatively early phenomenon and lasts for several hours. Upon purification of the crude elicitor extract by gel filtration and ion exchange chromatography, three elicitors were isolated. The three elicitors contained amino acid, sugar, and phosphate residues, and they have a decreased activity after partial chemical degradation of their sugar moiety.Elicitation of ethylene is not fungal species specific. Elicitors of phytoalexins, obtained from three Phytophtora species, enhanced ethylene biosynthesis in melon tissues.

  16. Recommended conservation of the names Streptococcus sanguis, Streptococcus rattus, Streptococcus cricetus, and seven other names included in the Approved Lists of Bacterial Names. Request for an opinion

    DEFF Research Database (Denmark)

    Kilian, Mogens

    2001-01-01

    With reference to the first Principle of the International Code of Nomenclature of Bacteria, which emphasizes stability of names, it is proposed that the original names Streptococcus sanguis, Streptococcus rattus, Streptococcus cricetus, Erwinia ananas, Eubacterium tarantellus, Lactobacillus sake...

  17. Microbial contaminants of cultured Hibiscus cannabinus and Telfaria ...

    African Journals Online (AJOL)

    The bacterial isolates includes Pseudomonas syringae pv phaseolicoli, Bacillus licheniformis, Bacillus subtilis, Corynebacterium sp and Erwinia sp. While fungal contaminats includes Alterneria tenius, Aspergillus niger, Aspergillus fumigatus and Fusarium culmorum. Possible sources of contamination and means of ...

  18. Bacterierot in Sedum hoe te handelen

    NARCIS (Netherlands)

    Helm, van der F.P.M.

    2009-01-01

    In sedum kan een bacterieziekte voorkomen die zich bij nat weer zeer snel door het gewas verpreidt. De vermoedelijke veroorzaker is Erwinia chrysanthemi (Dickeya). Deze bacterie zorgt in hyacint voor het gevreesde agressieve witsnot en in dahlia voor bacterieverwelkingsziekte

  19. Phosphate‐solubilization mechanism and in vitro plant growth promotion activity mediated by Pantoea eucalypti isolated from Lotus tenuis rhizosphere in the Salado River Basin (Argentina)

    National Research Council Canada - National Science Library

    Castagno, L.N; Estrella, M.J; Sannazzaro, A.I; Grassano, A.E; Ruiz, O.A

    2011-01-01

    ...‐PCR analysis, 17 non‐redundant strains were identified. Subsequently, they were found to be related to Pantoea , Erwinia , Pseudomonas , Rhizobium and Enterobacter genera, via 16S rRNA gene sequence analysis...

  20. Goed drogen bij hogere temperatuur voorkomt uitval : onderzoek Zantedeschia

    NARCIS (Netherlands)

    Leeuwen, van P.J.; Trompert, J.P.T.

    2003-01-01

    Onderzoek naar de oorzaak van Erwinia en verstening bij Zantedeschia-knollen tijdens en na de bewaring. PPO sector Bloembollen ging na wat de beste droog- en bewaarmethode is om deze problemen te voorkomen

  1. Onion thrips, Thrips tabaci, have gut bacteria that are closely related to the symbionts of the western flower thrips, Frankliniella occidentalis

    NARCIS (Netherlands)

    de Vries, E.J.; van der Wurff, A.W.G.; Jacobs, G.; Breeuwer, J.A.J.

    2008-01-01

    It has been shown that many insects have Enterobacteriaceae bacteria in their gut system. The western flower thrips, Frankliniella occidentalis Pergande [Thysanoptera: Thripidae], has a symbiotic relation with Erwinia species gut bacteria. To determine if other Thripidae species have similar

  2. Microbial contaminants of cultured Hibiscus cannabinus and Telfaria ...

    African Journals Online (AJOL)

    Administrator

    Key words: Micro-propagation, plant tissue culture, bacterial and fungal isolates, contamination. ... The aim of this research was to investigate, isolate and ... Erwinia spp. was detected ... considered as water and soil contaminants (Boxis and. 0.

  3. Sequence Diversity in the Dickeya fliC Gene: Phylogeny of the Dickeya Genus and TaqMan® PCR for 'D. solani', New Biovar 3 Variant on Potato in Europe

    OpenAIRE

    Van Vaerenbergh, Johan; Baeyen, Steve; De Vos, Paul; Maes, Martine

    2012-01-01

    Worldwide, Dickeya (formerly Erwinia chrysanthemi) is causing soft rot diseases on a large diversity of crops and ornamental plants. Strains affecting potato are mainly found in D. dadantii, D. dianthicola and D. zeae, which appear to have a marked geographical distribution. Furthermore, a few Dickeya isolates from potato are attributed to D. chrysanthemi and D. dieffenbachiae. In Europe, isolates of Erwinia chrysanthemi biovar 1 and biovar 7 from potato are now classified in D. dianthicola. ...

  4. Elicitation of Valerenic Acid in the Hairy Root Cultures of Valeriana ...

    African Journals Online (AJOL)

    Valerianaceae). MRD Torkamani, N Abbaspour, M Jafari, A Samadi. Abstract. Purpose: To investigate the effect of magnesium and calcium as abiotic elicitors on Valeriana officinalis hairy roots for scale-up production of valerenic acid. Methods: ...

  5. Chalcone synthase genes from milk thistle (Silybum marianum ...

    Indian Academy of Sciences (India)

    Leyva et al. 1995), UV treatments and blue light (Hartmann et al. 1998; Wade et al. 2001; Zhou et al. 2007), elicitor treatments such as salicylic acid and. Keywords. chalcone synthase; real-time PCR; silymarin; anthocyanin; Silybum marianum.

  6. Chlorogenic acids biosynthesis in Centella asiatica cells is not stimulated by salicylic acid manipulation

    CSIR Research Space (South Africa)

    Ncube, EN

    2016-07-01

    Full Text Available Exogenous application of synthetic and natural elicitors of plant defence has been shown to result in mass production of secondary metabolites with nutraceuticals properties in cultured cells. In particular, salicylic acid (SA) treatment has been...

  7. AvrPtoB Targets the LysM Receptor Kinase CERK1 to Promote Bacterial Virulence on Plants

    National Research Council Canada - National Science Library

    Gimenez-Ibanez, Selena; Hann, Dagmar R; Ntoukakis, Vardis; Petutschnig, Elena; Lipka, Volker; Rathjen, John P

    2009-01-01

    .... Here, we show that the Arabidopsis LysM receptor kinase CERK1, which is critical for chitin elicitor signaling and resistance to fungal pathogens, plays an essential role in restricting bacterial growth on plants...

  8. Hedonic "adaptation"

    Directory of Open Access Journals (Sweden)

    Paul Rozin

    2008-02-01

    Full Text Available People live in a world in which they are surrounded by potential disgust elicitors such as ``used'' chairs, air, silverware, and money as well as excretory activities. People function in this world by ignoring most of these, by active avoidance, reframing, or adaptation. The issue is particularly striking for professions, such as morticians, surgeons, or sanitation workers, in which there is frequent contact with major disgust elicitors. In this study, we study the ``adaptation'' process to dead bodies as disgust elicitors, by measuring specific types of disgust sensitivity in medical students before and after they have spent a few months dissecting a cadaver. Using the Disgust Scale, we find a significant reduction in disgust responses to death and body envelope violation elicitors, but no significant change in any other specific type of disgust. There is a clear reduction in discomfort at touching a cold dead body, but not in touching a human body which is still warm after death.

  9. Reference: 605 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available mportant part of plant responses to several hormonal and environmental cues, including auxin, blue light, and fungal elicitors. Howev...er, little is known about the signaling components that

  10. Surfactin Protects Wheat against Zymoseptoria tritici and Activates Both Salicylic Acid- and Jasmonic Acid-Dependent Defense Responses

    OpenAIRE

    Geraldine Le Mire; Ali Siah; Marie-Noëlle Brisset; Matthieu Gaucher; Magali Deleu; M. Haissam Jijakli

    2018-01-01

    Natural elicitors induce plant resistance against a broad spectrum of diseases, and are currently among the most promising biocontrol tools. The present study focuses on the elicitor properties of the cyclic lipopeptide surfactin on wheat, in order to stimulate the defenses of this major crop against the challenging fungal pathogen Zymoseptoria tritici. The protection efficacy of surfactin extracted from the strain Bacillus amyloliquefaciens S499 was investigated through greenhouse trials. Su...

  11. Plant Metabolic Engineering Strategies for the Production of Pharmaceutical Terpenoids

    OpenAIRE

    Lu, Xu; Tang, Kexuan; Li, Ping

    2016-01-01

    Pharmaceutical terpenoids belong to the most diverse class of natural products. They have significant curative effects on a variety of diseases, such as cancer, cardiovascular diseases, malaria and Alzheimer’s disease. Nowadays, elicitors, including biotic and abiotic elicitors, are often used to activate the pathway of secondary metabolism and enhance the production of target terpenoids. Based on Agrobacterium-mediated genetic transformation, several plant metabolic engineering strategies ho...

  12. Foliar Application of Benzothiadiazole and Salicylic Acid to Combat Sheath Blight Disease of Rice

    Directory of Open Access Journals (Sweden)

    Neerja SOOD

    2013-09-01

    Full Text Available A field study was undertaken to ascertain the effects of elicitors viz. benzothiadiazole (BTH and salicylic acid (SA on defense related enzymes viz. peroxidase, phenylalanine ammonia lyase, superoxide dismutase, chitinase and β-1,3-glucanase, and phenols in rice (Pusa Basmati I plants. First foliar spray of BTH (50 mg/kg and SA (50 mg/kg was done at the maximum tillering stage and inoculation with Rhizoctonia solani was carried 24 h after elicitor treatment. Elicitors were further sprayed at every growth stage. Time course analysis showed peak accumulation of defense related enzymes and phenols in the rice leaves treated with BTH and SA, and accumulation was the highest at the flowering stage. Higher enzymatic activity was observed in elicitor treated plants inoculated with R. solani. Compared to the untreated control plants, application of elicitors before R. solani inoculation significantly elicited the defense related enzymes and phenols. Moreover, application of elicitors had a positive effect on yield and disease reduction. It is suggested that pretreatment of rice leaves with BTH and SA could be used to enhance the level of protection against sheath blight and to improve rice yield in the fields.

  13. Bacteria associated with orchid roots and microbial production of auxin.

    Science.gov (United States)

    Tsavkelova, Elena A; Cherdyntseva, Tatiana A; Botina, Svetlana G; Netrusov, Alexander I

    2007-01-01

    Associative bacteria of terrestrial (Paphiopedilum appletonianum) and epiphytic (Pholidota articulata) tropical orchids were investigated. Microbial community of epiphytic plant differed from that of the terrestrial one. Streptomyces, Bacillus, Pseudomonas, Burkholderia, Erwinia and Nocardia strains populated Paphiopedilum roots, whereas Pseudomonas, Flavobacterium, Stenotrophomonas, Pantoea, Chryseobacterium, Bacillus, Agrobacterium, Erwinia, Burkholderia and Paracoccus strains colonized Pholidota roots. Endophytic bacteria populations were represented with less diversity: Streptomyces, Bacillus, Erwinia and Pseudomonas genera were isolated from P. appletonianum, and Pseudomonas, Bacillus, and Flavobacterium genera were isolated from Ph. articulata. Microorganisms produced indole-3-acetic acid (IAA). Variations in its biosynthesis among the strains of the same genus were also observed. The highest auxin level was detected during the stationary growth phase. Biological activity of microbial IAA was proved by treatment of kidney bean cuttings with bacterial supernatants, revealing considerable stimulation of root formation and growth.

  14. Rotting softly and stealthily.

    Science.gov (United States)

    Toth, Ian K; Birch, Paul R J

    2005-08-01

    The soft rot erwiniae, which are plant pathogens on potato and other crops world-wide, synthesize and secrete large quantities of plant cell wall degrading enzymes that are responsible for the soft rot phenotype, earning them the epithet 'brute force' pathogens. They have been distinguished from classic 'stealth' pathogens, such as Pseudomonas syringae, which possesses an extensive battery of Type III secreted effector proteins and phytotoxins to manipulate and suppress host defences. However, recent studies, including whole-genome sequencing, are revealing many components of stealth pathogenesis within the soft rot erwiniae (SRE), suggesting that 'stealth' and 'brute force' should not be regarded as mutually exclusive modes of pathogenesis.

  15. Basic emotions elicited by odors and pictures.

    Science.gov (United States)

    Croy, Ilona; Olgun, Selda; Joraschky, Peter

    2011-12-01

    The sense of olfaction is often reported to have a special relationship with emotional processing. Memories triggered by olfactory cues often have a very emotional load. On the other hand, basic negative or positive emotional states should be sufficient to cover the most significant functions of the olfactory system including ingestion, hazard avoidance, and social communication. Thus, we investigated whether different basic emotions can be evoked in healthy people through the sense of olfaction. We asked 119 participants which odor evokes one of the six basic emotions (happiness, disgust, anger, anxiety, sadness, and surprise); another 97 participants were asked about pictures evoking those emotions. The results showed that almost every participant could name an olfactory elicitor for happiness or disgust. Olfactory elicitors of anxiety were reported less frequently, but they were still reported by three-quarters of the participants. However, for sadness and anger only about half of the participants reported an olfactory elicitor, whereas significantly more named a visual cue. Olfactory emotion elicitors were mainly related to the classes of culture, plants, and food, and visual emotion elicitors were largely related to humans. This data supports the hypothesis that in the vast majority of people, few differentiated emotions can be elicited through the olfactory channel. These emotions are happiness, disgust, and anxiety. (c) 2011 APA, all rights reserved.

  16. A local accumulation of the Ralstonia solanacearum PopA protein in transgenic tobacco renders a compatible plant-pathogen interaction incompatible.

    Science.gov (United States)

    Belbahri, L; Boucher, C; Candresse, T; Nicole, M; Ricci, P; Keller, H

    2001-11-01

    Plants activate disease resistance responses when they recognize pathogen-derived molecules (elicitors). Frequently, recognition results in a hypersensitive response (HR), which is characterized by local host cell death at the infection site. Here we describe a genetic engineering approach to generate an HR in plants, whether or not an invading micro-organism produces a recognized elicitor. To that aim we created transgenic tobacco plants in which the pathogen-inducible promoter of the hsr203J gene from tobacco controls the expression of the popA elicitor gene from Ralstonia solanacearum. Because PopA itself also induces the hsr203J promoter, transgenic plants rapidly accumulate the bacterial elicitor in the pathogen infection sites. The elicitor becomes converted in plant tissues into its fully active derivatives PopA1-PopA3, showing that the previously observed processing events are not dependent on the bacterial type III secretion system. The outcome of induced PopA accumulation is a localized HR and a high degree of resistance of the transgenic plants to an oomycete pathogen. The system is functional in hybrids between different tobacco varieties, and we show that the engineered resistance, but not the associated cell death, is dependent on the salicylic acid signalling cascade. Although the approach is powerful in generating oomycete resistance, the induced HR might affect plant health. Its application thus requires a careful selection of individual transgenic lines and trials with various pathogens.

  17. Defense mechanisms of Solanum tuberosum L. in response to attack by plant-pathogenic bacteria.

    Science.gov (United States)

    Poiatti, Vera A D; Dalmas, Fernando R; Astarita, Leandro V

    2009-01-01

    The natural resistance of plants to disease is based not only on preformed mechanisms, but also on induced mechanisms. The defense mechanisms present in resistant plants may also be found in susceptible ones. This study attempted to analyze the metabolic alterations in plants of the potato Solanum tuberosum L. cv. Agata that were inoculated with the incompatible plant-pathogenic bacteria X. axonopodis and R. solanacearum, and the compatible bacterium E. carotovora. Levels of total phenolic compounds, including the flavonoid group, and the activities of polyphenol oxidase (PPO) and peroxidase (POX) were evaluated. Bacteria compatibility was evaluated by means of infiltration of tubers. The defense response was evaluated in the leaves of the potato plants. Leaves were inoculated depending on their number and location on the stem. Multiple-leaf inoculation was carried out on basal, intermediate, and apical leaves, and single inoculations on intermediate leaves. Leaves inoculated with X. axonopodis and with R. solanacearum showed hypersensitive responses within 24 hours post-inoculation, whereas leaves inoculated with E. carotovora showed disease symptoms. Therefore, the R. solanacearum isolate used in the experiments did not exhibit virulence to this potato cultivar. Regardless of the bacterial treatments, the basal leaves showed higher PPO and POX activities and lower levels of total phenolic compounds and flavonoids, compared to the apical leaves. However, basal and intermediate leaves inoculated with R. solanacearum and X. axonopodis showed increases in total phenolic compounds and flavonoid levels. In general, multiple-leaf inoculation showed the highest levels of total phenolics and flavonoids, whereas the single inoculations resulted in the highest increase in PPO activity. The POX activity showed no significant difference between single- and multiple-leaf inoculations. Plants inoculated with E. carotovora showed no significant increase in defense mechanisms

  18. Domain Modeling: NP_001093214.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001093214.1 chr8 Crystal Structure Analysis of Pectate Lyase PelI from Erwinia c...hrysanthemi p3b4na_ chr8/NP_001093214.1/NP_001093214.1_holo_328-648.pdb swppa 329E,330A,331R,346S,347S,348L,

  19. QTL analysis of the genetic architecture determining resistance to fire blight in an apple progeny

    NARCIS (Netherlands)

    Calenge, F.; Drouet, D.; Weg, van de W.E.; Brisset, M.N.; Paulin, J.P.; Durel, C.E.

    2004-01-01

    Fire blight, caused by the bacterial pathogen Erwinia amylovora, is one of the most destructive diseases of apple (Malus x domestica). In order to analyse the genetic determinism of resistance to fire blight in apple, a quantitative trait analysis (QTL) approach was used. A F1 progeny of 164

  20. Biological control of post harvest disease caused by Aspergillus ...

    African Journals Online (AJOL)

    Biological control of post harvest disease caused by Aspergillus flavus on stored lemon fruits. ... Erwinia chrysanthemi RK-67 and Bacillus subtilis RK-6 treatments reduced disease severity on both lemon cultivars. Furthermore, both the cell suspension and culture filtrates of Burkholderia cepacia strain RK- 277 reduced ...

  1. A study on bacterial softrot in witloof chicory

    NARCIS (Netherlands)

    Schober, B.M.

    1998-01-01

    The production process of witloof chicory, which consists of the root production stage, the storage of the roots and the forcing of the chicory heads, was monitored for the presence of softrot bacteria. In the Netherlands, bacterial softrot in chicory is caused by Erwinia

  2. Growth and Transmission of Gut Bacteria in the Western Flower Thrips Frankliniella occidentalis

    NARCIS (Netherlands)

    de Vries, E.J.; Jacobs, G.; Breeuwer, J.A.J.

    2001-01-01

    The Western flower thrips (Frankliniella occidentalis), a polyphagous insect with global distribution, has a permanent association with a near Erwinia species TAC bacterium in its hindgut. Since this bacterium is able to grow outside the thrips, it is a facultative symbiont that is not completely

  3. 2007 Heartland Security Conference and Exhibition - Technology for Defense and Homeland Security Readiness

    Science.gov (United States)

    2007-07-11

    grown in-house to contaminate pastries served to 45 co-workers 12 ill, 4 hospitalizations Slide credit: IFT Threat as a Weapon 1989: Chile ...Virus Poliovirus Type 1 Rotavirus SA-11 SARS coronavirus Brucella abortus Enterobacter aerogenes Enterococcus faecalis Erwinia herbicola Francisella

  4. Arabidopsis CDS blastp result: AK071193 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK071193 J023088F15 At3g02690.1 integral membrane family protein similar to PecM protein (GI:5852331) {Voges...ella indigofera} and PecM protein (SP:P42194) [Erwinia chrysanthemi] 1e-54 ...

  5. Lack of evidence for western flower thrips biotypes base don intra and inter-strain variation in gut bacteria

    NARCIS (Netherlands)

    Vries, de E.J.; Jacobs, G.; Kogel, de W.J.; Hoek, van der M.; Breeuwer, J.A.J.

    2010-01-01

    Western flower thrips is a polyphagous insect, which during the last 30 years has become a world wide pest. It was found earlier that these thrips are associated with a type of Erwinia species gut bacteria. In this study we examine the variation of bacteria within and between thrips individuals and

  6. Western Flower Thrips (Thysanoptera: Thripidae) preference for thrips-damaged leaves over fresh leaves enables uptake of symbiotic gut bacteria

    NARCIS (Netherlands)

    de Vries, E.J.; Vos, R.A.; Jacobs, G.; Breeuwer, J.A.J.

    2006-01-01

    To understand the evolution of insect gut symbionts it is important to determine how they are passed on to the next generation. We studied this process in Erwinia species bacteria that inhabit the gut of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). This is

  7. Microbiological studies of cockroaches from three localities in ...

    African Journals Online (AJOL)

    Opportunistic pathogens like species of Pseudomonas, Klebsiella and Vibrio and food spoilage bacteria such as species of Enterobacter, Citrobacter, Escherichia, Erwinia, and Pseudomonas were also found. Proper care in disposal of food remnants and overall cleanliness at the households prevents cockroaches from ...

  8. Domain Modeling: NP_742111.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_742111.1 chr20 Crystal Structure Analysis of Pectate Lyase PelI from Erwinia chr...ysanthemi p3b4na_ chr20/NP_742111.1/NP_742111.1_holo_29-268.pdb swppa 30A,31D,32A,46S,47A,48P,65R,66Q,68S,70

  9. Domain Modeling: NP_000513.2 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_000513.2 chr7 Crystal Structure Analysis of Pectate Lyase PelI from Erwinia chry...santhemi p3b4na_ chr7/NP_000513.2/NP_000513.2_holo_20-305.pdb swppa 21D,22N,23G,38A,39A,40A,57G,58F,60H,62A,

  10. Fire blight resistance in wild accessions of Malus sieversii

    Science.gov (United States)

    Fire blight (Erwinia amylovora) is a devastating bacterial disease in apple that results in severe economic losses. Epidemics are becoming more common as susceptible cultivars and rootstocks are being planted, and control is becoming more difficult as antibiotic-resistant strains develop. Resistan...

  11. Cisgenic Approach for improved disease resistance in apple

    NARCIS (Netherlands)

    Broggini, G.A.L.; Durel, C.E.; Vergne, E.; Chevreau, E.; Fahrentrapp, J.; Vanblaere, T.; Peil, A.; Flachowsky, H.; Hanke, M.V.; Krens, F.A.; Schouten, H.J.; Gessler, C.

    2013-01-01

    Swiss and more generally European apple (Malus × domestica) production is hampered by several diseases, the most destructive being fire blight, caused by Erwinia amylovora. On the other hand, there are apple scab, caused by Venturia inaequalis and powdery mildew, caused by Podosphaera leucotricha,

  12. Bruikbaarheid vacuümtoets bij hyacinten : Voortgezet diagnostisch onderzoek 2012

    NARCIS (Netherlands)

    Leeuwen, van P.J.; Dees, R.H.L.

    2013-01-01

    Bij aardappel is door HZPC te Metslawier een nieuwe toets ontwikkeld om nog nauwkeuriger Erwinia (Pectobacterium, Dickeya) in de knollen vast te stellen. Tot op heden werden de naveleinden van een knol getoetst. Door de knollen gedurende een week bij hoge temperateren onder vacuüm te bewaren wordt

  13. Author Details

    African Journals Online (AJOL)

    Abstract PDF · Vol 10, No 79 (2011) - Articles The influence of carbon source and calcium on the production of proteases by Erwinia chrysanthemi. Abstract PDF · Vol 12, No 26 (2013) - Articles A marine bacterium, Oceanobacillus sp. Pinky, isolated from Algoa Bay sediment produces a thermostable glycoprotein flocculant

  14. Geneva apple rootstock performance in New York state and progress in commercialization

    Science.gov (United States)

    A number of new apple rootstocks from the Cornell/USDA apple rootstock breeding project, located at Geneva NY which are resistant to the bacterial disease fire blight (Erwinia amylovora) are rapidly becoming available. Some named rootstock genotypes from this program have previously been tested in s...

  15. Identification and phylogenetic analysis of a bacterium isolated from ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-04

    Jul 4, 2008 ... Inulin. -. L-arabinose. -. Inositol. -. D-Mannitol. -. + = Positive; – = negative; ± = feeble ferment. Enterobacteriaceae include Genera Escherichia,. Edwardsiella, Citrobacter, Salmonella, Shigella, Klebsie- lla, Enterobacter, Hafnia, Serratia, Proteus, Yersinia and. Erwinia in Bergey's Manual of Determinative ...

  16. Microbiological quality of raw and processed farm reared ...

    African Journals Online (AJOL)

    Indicator organisms especially Salmonella paratyphi and Aerobacter aerogenes seemed to be more common in the isolated samples with the highest number among the isolated bacteria especially in the boiled shell-on periwinkle and raw periwinkle meat. Some psychotropic organisms such as Erwinia amylovora and ...

  17. Aerobic Denitrification as an Innovative Method for In-Situ Biological Remediation of Contaminated Subsurface Sites

    Science.gov (United States)

    1989-01-01

    Neisseria Thiobacillus Dac tylsporangium Nocardia Thiomicrospira Enterobacter Paracoccus Veillonella. Erw~inia Pasteurella Vibrio, Escherichia From...Arthrobacter simplex Nocardia brasllensis Pseudomonas mendocina Arthrobacter tumescens Nocardia asterlodes Pseudomonas fluorescens Arthrobacter...citreus Nocardla formicae Pseudomonas chioraphis Arthrobacter rerregens Nocardia Polychromogenes Pseudomonas aureofac lens Arthrobacter flavescens Nocardla

  18. The influence of carbon source and calcium on the production of ...

    African Journals Online (AJOL)

    Erwinia chrysanthemi (Ec) is the causative agent of soft rot diseases in many plants. In order to cause disease, it produces hydrolytic enzymes, which are involved in the degradation of plant tissue. However, the role of proteases in its pathogenicity to plants is not well understood. E. chrysanthemi targets the host's middle ...

  19. A simple and rapid lysis method for preparation of genomic DNA ...

    African Journals Online (AJOL)

    Yomi

    2011-12-07

    proAB) F' (traD36. proA+B+ lacq lacZ∆M15) and Erwinia .... Bennis S, Chami F, Chami N, Bouchikhi T, Remmal A (2004a). Surface alteration of Saccharomyces cerevisiae induced by thymol and eugenol. Lett. Appl. Microbiol.

  20. Effect of low-temperature plasma treatment on the growth and reproduction rate of some plant pathogenic bacteria

    Czech Academy of Sciences Publication Activity Database

    Mráz, Ivan; Beran, P.; Šerá, Božena; Gavril, B.; Hnatiuc, E.

    2014-01-01

    Roč. 96, č. 1 (2014), s. 63-67 ISSN 1125-4653 Institutional research plan: CEZ:AV0Z50510513 Institutional support: RVO:60077344 ; RVO:67179843 Keywords : LTAPP * bacterial growth * Clavibacter michigannsis subsp michiganensis * Escherichia coli * Erwinia amylovora Subject RIV: EE - Microbiology, Virology; BO - Biophysics (UEK-B) Impact factor: 1.043, year: 2014

  1. Slijmerige killers : over boosdoeners en remedie

    NARCIS (Netherlands)

    Bulle, A.A.E.

    2013-01-01

    In diverse siergewassen veroorzaken bacteriën steeds vaker grote problemen, onder meer in zomerbloemen. Erwinia-, xanthomonas- en psuedomonassoorten bijvoorbeeld kunnen veel schade veroorzaken. Echte bestrijding is niet mogelijk, maar met een goede weerstand kan een plant zich beter weren.

  2. Recommended conservation of the names Streptococcus sanguis, Streptococcus rattus, Streptococcus cricetus, and seven other names included in the Approved Lists of Bacterial Names. Request for an opinion.

    Science.gov (United States)

    Kilian, M

    2001-03-01

    With reference to the first Principle of the International Code of Nomenclature of Bacteria, which emphasizes stability of names, it is proposed that the original names Streptococcus sanguis, Streptococcus rattus, Streptococcus cricetus, Erwinia ananas, Eubacterium tarantellus, Lactobacillus sake, Nitrosococcus oceanus, Pseudomonas betle, Rickettsia canada and Streptomyces rangoon, all included in the Approved Lists of Bacterial Names, be conserved. Request for an Opinion.

  3. Detection, identification and differentiation of Pectobacterium and Dickeya species causing potato blackleg and tuber soft rot: a review

    NARCIS (Netherlands)

    Czajkowski, R.L.; Pérombelon, M.C.M.; Jafra, S.; Lojkowska, E.; Potrykus, M.; Wolf, van der J.M.; Sledz, W.

    2015-01-01

    The soft rot Enterobacteriaceae (SRE) Pectobacterium and Dickeya species (formerly classified as pectinolytic Erwinia spp.) cause important diseases on potato and other arable and horticultural crops. They may affect the growing potato plant causing blackleg and are responsible for tuber soft rot in

  4. Rock phosphate solubilization by the ectomycorrhizal fungus ...

    African Journals Online (AJOL)

    In the present study, few mycorrhizal helper bacterial (MHB) strains such as Pseudomonas putida, Erwinia herbicola and Bacillus subtilis were isolated and identified from surface sterilized basidiomata and mycorrhizosphere of an ectomycorrhizal fungus Laccaria fraterna association with Eucalyptus globulus. To evaluate ...

  5. Comparative analysis of tandem T7-like promoter containing regions in enterobacterial genomes reveals a novel group of genetic islands | Center for Cancer Research

    Science.gov (United States)

    Twelve prophage-like T7 islands have been discovered in pathogenic bacterial genomes. These islands contain two or three tandem T7-like promoters that should be activated when a bacterial cell is infected by bacteriophage T7 or a related phage. The illustration shows genetic maps for four of the islands, Ty2, BS512, E22 and ECA, which are found in the genomes of S. enterica Ty2, S. boydii BS512, E. coli E22 and E. carotovora SCRI1043 respectively.

  6. AcEST: DK951170 [AcEST

    Lifescience Database Archive (English)

    Full Text Available domain-containing protein OS=Brassi... 126 1e-27 tr|Q94G57|Q94G57_PETCR Immediate-early fungal elicitor pro...tein C... 125 2e-27 tr|Q93VZ1|Q93VZ1_PETCR Immediate-early fungal elicitor protein C... 125 2e-27 tr|A7P9L6|...A7P9L6_VITVI Chromosome chr3 scaffold_8, whole genome ... 125 3e-27 tr|B6UDD7|B6UDD7_MAIZE Immediate...protein 13-1-1 OS=Gly... 123 1e-26 tr|B6SVN8|B6SVN8_MAIZE Immediate-early fungal elicitor protein C... 122 2...0 AL+ L A + +R I L ++L Sbjct: 124 SRAAALRRLRGFARDSEKNRVLIAAHNAKEILIRIL 159 >tr|Q94G57|Q94G57_PETCR Immediate

  7. Aspergillus niger Enhance Bioactive Compounds Biosynthesis As Well As Expression of Functional Genes in Adventitious Roots of Glycyrrhiza uralensis Fisch.

    Science.gov (United States)

    Li, Jing; Wang, Juan; Li, Jinxin; Liu, Dahui; Li, Hongfa; Gao, Wenyuan; Li, Jianli; Liu, Shujie

    2016-02-01

    In the present study, the culture conditions for the accumulation of Glycyrrhiza uralensis adventitious root metabolites in balloon-type bubble bioreactors (BTBBs) have been optimized. The results of the culture showed that the best culture conditions were a cone angle of 90° bioreactor and 0.4-0.6-0.4-vvm aeration volume. Aspergillus niger can be used as a fungal elicitor to enhance the production of defense compounds in plants. With the addition of a fungal elicitor (derived from Aspergillus niger), the maximum accumulation of total flavonoids (16.12 mg g(-1)) and glycyrrhetinic acid (0.18 mg g(-1)) occurred at a dose of 400 mg L(-1) of Aspergillus niger resulting in a 3.47-fold and 1.8-fold increase over control roots. However, the highest concentration of polysaccharide (106.06 mg g(-1)) was achieved with a mixture of elicitors (Aspergillus niger and salicylic acid) added to the medium, resulting in a 1.09-fold increase over Aspergillus niger treatment alone. Electrospray ionization tandem mass spectrometry (ESI-MS(n)) analysis was performed, showing that seven compounds were present after treatment with the elicitors, including uralsaponin B, licorice saponin B2, liquiritin, and (3R)-vestitol, only identified in the mixed elicitor treatment group. It has also been found that elicitors (Aspergillus niger and salicylic acid) significantly upregulated the expression of the cinnamate 4-hydroxylase (C4H), β-amyrin synthase (β-AS), squalene epoxidase (SE) and a cytochrome P450 monooxygenase (CYP72A154) genes, which are involved in the biosynthesis of bioactive compounds, and increased superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activity.

  8. Three cases of anaphylaxis following injection of a depot corticosteroid with evidence of IgE sensitization to macrogols rather than the active steroid

    DEFF Research Database (Denmark)

    Brandt, Nicolaj; Garvey, Lene H; Bindslev-Jensen, Ulla

    2017-01-01

    of anaphylaxis to excipients such as macrogols is needed, especially when allergy tests for the active drug is negative and in patients with a history of repeated anaphylaxis to seemingly unrelated drugs. To establish the correct diagnosis it is important to test with the exact formulation of the culprit drug......We present three cases with anaphylaxis after injection of a depot corticosteroid. First, the steroid was suspected as the elicitor, but after evaluation the excipient macrogol was found to be the elicitor. One of the patients had reactions to several unrelated drugs. Increased awareness...

  9. Botanicals to Control Soft Rot Bacteria of Potato

    Directory of Open Access Journals (Sweden)

    M. M. Rahman

    2012-01-01

    Full Text Available Extracts from eleven different plant species such as jute (Corchorus capsularis L., cheerota (Swertia chiraita Ham., chatim (Alstonia scholaris L., mander (Erythrina variegata, bael (Aegle marmelos L., marigold (Tagetes erecta, onion (Allium cepa, garlic (Allium sativum L., neem (Azadiracta indica, lime (Citrus aurantifolia, and turmeric (Curcuma longa L. were tested for antibacterial activity against potato soft rot bacteria, E. carotovora subsp. carotovora (Ecc P-138, under in vitro and storage conditions. Previously, Ecc P-138 was identified as the most aggressive soft rot bacterium in Bangladeshi potatoes. Of the 11 different plant extracts, only extracts from dried jute leaves and cheerota significantly inhibited growth of Ecc P-138 in vitro. Finally, both plant extracts were tested to control the soft rot disease of potato tuber under storage conditions. In a 22-week storage condition, the treated potatoes were significantly more protected against the soft rot infection than those of untreated samples in terms of infection rate and weight loss. The jute leaf extracts showed more pronounced inhibitory effects on Ecc-138 growth both in in vitro and storage experiments.

  10. The high molecular weight dipeptidyl peptidase IV Pol d 3 is a major allergen of Polistes dominula venom

    DEFF Research Database (Denmark)

    Schiener, Maximilian; Hilger, Christiane; Eberlein, Bernadette

    2018-01-01

    Hymenoptera venom allergy can cause severe anaphylaxis in untreated patients. Polistes dominula is an important elicitor of venom allergy in Southern Europe as well as in the United States. Due to its increased spreading to more moderate climate zones, Polistes venom allergy is likely to gain imp...

  11. Isolation and identification of phosphatidic acid targets from plants.

    NARCIS (Netherlands)

    Testerink, C.; Dekker, H.L.; Lim, Z.-Y.; Johns, M.K.; Holmes, A.B.; de Koster, C.G.; Ktisakis, N.T.; Munnik, T.

    2004-01-01

    Phosphatidic acid (PA) is emerging as an important lipid signalling molecule. In plants, it is implicated in various stress-signalling pathways and is formed in response to wounding, osmotic stress, cold stress, pathogen elicitors, Nod factors, ethylene and abscisic acid. How PA exerts its effects

  12. Elicitation and precursor feeding influence phenolic acids ...

    African Journals Online (AJOL)

    Plant cell cultures have been industrially used for the synthesis of secondary metabolites. Different elicitors, [jasmonic acid (JA), salicylic acid (SA) and ethephone (E)] and precursors [shicimic acid (SH) and phenylalanine (PHE)] were independently used to enhance the synthesis of phenolics in suspension cultures of Vitis ...

  13. Alleviation of oxidative stress induced by spider mite invasion ...

    African Journals Online (AJOL)

    Spider mite invasion induces oxidative stress on bean plants and increased soluble sugars, phenole, proline and peroxidase activity, but decreased catalase activity and ascorbic acid and carotenoid concentration. Application of elicitors significantly enhanced spider mite tolerance by decreasing hydrogen peroxide, ...

  14. Biological control of Meloidogyne incognita by Trichoderma ...

    African Journals Online (AJOL)

    Similar tests were carried out on inoculated plants treated with such ISR elicitors to search for possible enzyme activity changes as a result of resistance induction. Nematode infection did not cause any significant changes in GLUC activity, whilst PPO activity was enhanced in inoculated with respect to uninoculated roots.

  15. Foliar application of systemic acquired resistance (SAR) inducers for ...

    African Journals Online (AJOL)

    nbuensanteai

    2013-08-14

    Aug 14, 2013 ... Chitosan and benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) are active-elicitors that induce protection in grapevine against several diseases. In this study, treatment of grapevine with chitosan and BTH provided protection to anthracnose, caused by Sphaceloma ampelinum. Chitosan.

  16. Role of Large Cabbage White butterfly male-derived compounds in elicitation of direct and indirect egg-killing defenses in the black mustard

    NARCIS (Netherlands)

    Fatouros, N.E.; Voirol, L.R.P.; Drizou, Fryni; Doan, Quyen T.; Pineda, Ana; Frago, Enric; Loon, van J.J.A.

    2015-01-01

    To successfully exert defenses against herbivores and pathogens plants need to recognize reliable cues produced by their attackers. Up to now, few elicitors associated with herbivorous insects have been identified. We have previously shown that accessory reproductive gland secretions associated

  17. The quantitative genetics of disgust sensitivity

    NARCIS (Netherlands)

    Sherlock, J.M.; Zietsch, B.P.; Tybur, J.M.; Jern, P.

    2016-01-01

    Response sensitivity to common disgust elicitors varies considerably among individuals. The sources of these individual differences are largely unknown. In the current study, we use a large sample of female identical and nonidentical twins (N = 1,041 individuals) and their siblings (N = 170) to

  18. When the Wolf Wears Sheep’s Clothing: Individual Differences in the Desire to be Liked Influence Nonconscious Behavioural Mimicry

    NARCIS (Netherlands)

    Ashton-James, C.E.; Levordashka, A.L.

    2013-01-01

    Current research into the elicitors of nonconscious behavioral mimicry focuses almost exclusively on prosocial motives. Alternatively, the present research investigates whether the self-centered desire to be liked by others also induces mimicry. We investigate this issue by measuring the mimicry

  19. Treatment of chronic phantom limb pain using a trauma-focused psychological approach

    NARCIS (Netherlands)

    de Roos, C.; Veenstra, M.A.; de Jongh, A.; den Hollander-Gijsman, M.E.; van der Weer, N.J.A.; Zitman, F.G.; van Rood, Y.R.

    2010-01-01

    BACkgRound: Chronic phantom limb pain (PLP) is a disabling chronic pain syndrome for which regular pain treatment is seldom effective. Pain memories resulting from long-lasting preamputation pain or pain flashbacks, which are part of a traumatic memory, are reported to be powerful elicitors of PLP.

  20. Treatment of Chronic Phantom Limb Pain Using a Trauma-Focused Psychological Approach

    Directory of Open Access Journals (Sweden)

    C de Roos

    2010-01-01

    Full Text Available BACKGROUND: Chronic phantom limb pain (PLP is a disabling chronic pain syndrome for which regular pain treatment is seldom effective. Pain memories resulting from long-lasting preamputation pain or pain flashbacks, which are part of a traumatic memory, are reported to be powerful elicitors of PLP.

  1. Elicitation, an Effective Strategy for the Biotechnological Production of Bioactive High-Added Value Compounds in Plant Cell Factories

    Directory of Open Access Journals (Sweden)

    Karla Ramirez-Estrada

    2016-02-01

    Full Text Available Plant in vitro cultures represent an attractive and cost-effective alternative to classical approaches to plant secondary metabolite (PSM production (the “Plant Cell Factory” concept. Among other advantages, they constitute the only sustainable and eco-friendly system to obtain complex chemical structures biosynthesized by rare or endangered plant species that resist domestication. For successful results, the biotechnological production of PSM requires an optimized system, for which elicitation has proved one of the most effective strategies. In plant cell cultures, an elicitor can be defined as a compound introduced in small concentrations to a living system to promote the biosynthesis of the target metabolite. Traditionally, elicitors have been classified in two types, abiotic or biotic, according to their chemical nature and exogenous or endogenous origin, and notably include yeast extract, methyl jasmonate, salicylic acid, vanadyl sulphate and chitosan. In this review, we summarize the enhancing effects of elicitors on the production of high-added value plant compounds such as taxanes, ginsenosides, aryltetralin lignans and other types of polyphenols, focusing particularly on the use of a new generation of elicitors such as coronatine and cyclodextrins.

  2. Eliciting Patients’ Health Concerns in Consulting Rooms and Wards in Vietnamese Public Hospitals

    Directory of Open Access Journals (Sweden)

    Huong Thi Linh Nguyen

    2018-03-01

    Full Text Available This article examines the doctor’s elicitation of the patient’s presenting health concern in two clinical settings in the Vietnamese public hospital system: the consulting room and the ward. The data were taken from 66 audio-recorded consultations. Our analysis shows that the elicitors used by the doctor in the consulting room often communicate a weak epistemic stance towards the patient’s health issue, while those used in the ward tend to signal a strong epistemic stance. In addition, this contrast between the elicitors employed in the consulting room and the ward is evident in our data regardless of whether the consultation is a first visit or a same follow-up (in which the doctor is the same one that treated the patient on their last visit, though the contrast is less clear for different follow-ups (in which the doctor has not treated the patient before. An additional finding is that the clinical setting has some bearing on the use of inappropriate elicitation formats (in which the doctor opens the visit with an elicitor which is more appropriate for another type of visit. The precise way in which each of the consulting room and the ward operates is, of course, a feature of the Vietnamese public hospital system itself. Hence, the overall contrast between the elicitors and elicitation formats used in these two settings illustrates how, on a more general level, the institutional context can have an impact on doctor-patient communication.

  3. Establishment and characterization of American elm cell suspension cultures

    Science.gov (United States)

    Steven M. Eshita; Joseph C. Kamalay; Vicki M. Gingas; Daniel A. Yaussy

    2000-01-01

    Cell suspension cultures of Dutch elm disease (DED)-tolerant and DED-susceptible American elms clones have been established and characterized as prerequisites for contrasts of cellular responses to pathogen-derived elicitors. Characteristics of cultured elm cell growth were monitored by A700 and media conductivity. Combined cell growth data for all experiments within a...

  4. Quantitative expression of defense-related genes induced in ...

    African Journals Online (AJOL)

    XP LITE

    2013-03-20

    Mar 20, 2013 ... elicitors, quantitative reverse transcriptase PCR (qRT-PCR). INTRODUCTION ... of this disease in nurseries(http://extranet.agricultura.gov.br/agrofit_cons/pr .... qRT-PCR. The qRT-PCR expression analysis was performed using SYBR green in the ABI PRISM 7500 Fast Real-Time PCR system (Applied ...

  5. Effects of gastrointestinal digestion and heating on the allergenicity of the kiwi allergens Act d 1, actinidin, and Act d 2, a thaumatin-like protein

    NARCIS (Netherlands)

    Bublin, Merima; Radauer, Christian; Knulst, Andre; Wagner, Stefan; Scheiner, Otto; Mackie, Alan R.; Mills, E. N. Clare; Breiteneder, Heimo

    2008-01-01

    Kiwifruit is a significant elicitor of allergy both in children and adults. Digestibility of two kiwifruit allergens, actinidin (Act d 1) and thaumatin-like protein (Act d 2), was assessed using an in vitro digestion system that approximates physiological conditions with respect to the passage of

  6. Silicon induced systemic defense responses in perennial ryegrass against Magnaporthe oryzae infection

    Science.gov (United States)

    Sustainable integrated disease management for gray leaf spot of perennial ryegrass may involve use of plant defense elicitors with compatible traditional fungicides to reduce disease incidence and severity. Silicon (Si) is a potential inducer or modulator of plant defenses against different pathogen...

  7. The structures and functions of oligosaccharins

    Energy Technology Data Exchange (ETDEWEB)

    Albersheim, P.

    1990-08-01

    Abstracts of papers published or in press reporting work supported by this grant proposal during the past year are given here to describe the progress we have made in this research project. Topics include morphogenesis regulation by cell wall oligosaccharins; regulation of pectic enzymes, pathogen interactions with cell wall constituents; oligosaccharins as regulatory molecules; and characterization of oligosaccharide elicitors.

  8. Children's Physical Attractiveness and Sex as Determinants of Adult Punitiveness

    Science.gov (United States)

    Dion, Karen K.

    1974-01-01

    Two studies investigated the influence of a child's physical attractiveness and sex as potential elicitors of differential adult punitiveness. Assessed were the reactions of 40 women and 44 men. Results reveal differences in men's and women's reactions and suggest differences in their orientation towards children's task behavior. (Author/SDH)

  9. Understanding plant immunity as a surveillance system to detect invasion

    NARCIS (Netherlands)

    Cook III, D.E.; Mesarich, C.H.; Thomma, B.P.H.J.

    2015-01-01

    Various conceptual models to describe the plant immune system have been presented. The most recent paradigm to gain wide acceptance in the field is often referred to as the zigzag model, which reconciles the previously formulated gene-for-gene hypothesis with the recognition of general elicitors in

  10. Molecular characterization of Api g 2, a novel allergenic member of the lipid-transfer protein 1 family from celery stalks

    NARCIS (Netherlands)

    Gadermaier, Gabriele; Egger, Matthias; Girbl, Tamara; Erler, Anja; Harrer, Andrea; Vejvar, Eva; Liso, Marina; Richter, Klaus; Zuidmeer, Laurian; Mari, Adriano; Ferreira, Fatima

    2011-01-01

    Celery represents a relevant cross-reactive food allergen source in the adult population. As the currently known allergens are not typical elicitors of severe symptoms, we aimed to identify and characterize a non-specific lipid transfer protein (nsLTP). MS and cDNA cloning were applied to obtain the

  11. Enhancement of Diosgenin Production in Plantlet and Cell Cultures ...

    African Journals Online (AJOL)

    Purpose: To study the effect of palmarumycin C13, an elicitor from the endophytic fungus Berkleasmium sp. Dzf12, on growth and diosgenin production in plantlet or cell cultures of its host plant, Dioscorea zingiberensis. Methods: Palmarumycin C13 was isolated from the ethyl acetate extract of the endophytic fungus.

  12. Footsteps from insect larvae damage leaf surfaces and initiate rapid responses

    NARCIS (Netherlands)

    Hall, D.E.; MacGregor, K.B.; Nijsse, J.; Bown, A.W.

    2004-01-01

    Plant resistance to insect herbivory involves gene expression in response to wounding and the detection of insect elicitors in oral secretions (Kessler and Baldwin, 2002, Ann. Rev. Plant/ Biol. 53: 299¿328). However, crawling insect larvae stimulate the synthesis of 4-aminobutyrate within minutes

  13. Alternativen beim Pflanzenschutz?

    Science.gov (United States)

    Mendgen, Kurt

    1983-05-01

    The control of plant diseases may be improved by influencing the development of a parasite in its host. The role of elicitors and inducers for the induction of the plant's defense reactions and the use of hyperparasites is discussed as a part of an integrated pest management system of rust fungi.

  14. Convergent evolution of filamentous microbes towards evasion of glycan-triggered immunity

    NARCIS (Netherlands)

    Rovenich, Hanna; Zuccaro, Alga; Thomma, Bart P.H.J.

    2016-01-01

    I. II. III. IV. V. VI. References Summary: All filamentous microbes produce and release a wide range of glycans, which are essential determinants of microbe-microbe and microbe-host interactions. Major cell wall constituents, such as chitin and β-glucans, are elicitors of host immune responses.

  15. Chitosan oligosaccharides-triggered innate immunity contributes to oilseed rape resistance against Sclerotinia sclerotiorum

    DEFF Research Database (Denmark)

    Yin, Heng; Yan, Li; HongYan, Zhang

    2013-01-01

    Chitosan oligosaccharides (collectively, oligochitosan, or COS) are considered to be potent plant immunity elicitors. In this article, the induction of resistance to Sclerotinia sclerotiorum in Brassica napus L. var. Huyou 15 by COS is studied. Even though COS (50 mg mL1) did not affect radial...

  16. Identification of tomato phosphatidylinositol-specific phospholipase-C (PI-PLC) family members and the role of PLC4 and PLC6 in HR and disease resistance

    NARCIS (Netherlands)

    Vossen, J.H.; Abd-El-Haliem, A.; Fradin, E.F.; Berg, van den G.C.M.; Ekengren, S.K.; Meijer, H.J.G.; Seifi Abdolabad, A.R.; Bai, Y.; Have, ten A.; Munnik, T.; Thomma, B.P.H.J.; Joosten, M.H.A.J.

    2010-01-01

    The perception of pathogen-derived elicitors by plants has been suggested to involve phosphatidylinositol-specific phospholipase-C (PI-PLC) signalling. Here we show that PLC isoforms are required for the hypersensitive response (HR) and disease resistance. We characterised the tomato [Solanum

  17. Genomewide analysis of the chitinase gene family in Populus ...

    Indian Academy of Sciences (India)

    2013-04-02

    Apr 2, 2013 ... class II chitinase genes, was induced by methyl jasmonate. (MeJA) rather than other treatments. POPTR_0012s01150.1 is a class III chitinase gene. It was sensitive to elicitor and wound inducements but insensitive to salicylid acid. (SA) and MeJA treatments. When Populus was infected by. M. brunnea, the ...

  18. Effector-mediated suppression of chitin-triggered immunity by Magnaporthe oryzae is necessary for rice blast disease

    NARCIS (Netherlands)

    Mentlak, T.A.; Kombrink, A.; Shinya, T.; Ryder, L.S.; Otomo, I.; Saitoh, H.; Terauchi, R.; Nishizawa, Y.; Shibuya, N.; Thomma, B.P.H.J.; Talbot, N.J.

    2012-01-01

    Plants use pattern recognition receptors to defend themselves from microbial pathogens. These receptors recognize pathogen-associated molecular patterns (PAMPs) and activate signaling pathways that lead to immunity. In rice (Oryza sativa), the chitin elicitor binding protein (CEBiP) recognizes

  19. Root and shoot jasmonic acid induction differently affects the foraging behavior of Cotesia glomerata under semi-field conditions

    NARCIS (Netherlands)

    Qiu, B.L.; Van Dam, N.M.; Harvey, J.A.; Vet, L.E.M.

    2012-01-01

    Plants can accumulate and release defensive chemicals by activating various signaling pathways when they are damaged by herbivores or pathogens. The jasmonic acid pathway is activated after damage by chewing herbivores. Here we used jasmonic acid (JA) as an exogenous elicitor to induce feral cabbage

  20. PEPR2 is a second receptor for the Pep1 and Pep2 peptides and contributes to defense responses in arabidopsis

    Science.gov (United States)

    A 23-amino acid peptide, AtPep1, and its homologues are endogenous elicitors in Arabidopsis, inducing defense related genes. AtPep1 enhances resistance to a root pathogen, Pythium irregulare, through the salicylic acid, jasmonic acid, ethylene, and reactive oxygen species signaling pathways. AtPep...