Voici les éléments 1 - 10 sur 21
  • Publication
    Métadonnées seulement
    The taxon-specific paralogs of grapevine PRLIP genes are highly induced upon powdery mildew infection
    (2012)
    Szalontai, Balint
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    Stranczinger, Szilvia
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    Palfalvi, Gergo
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    ;
    Jakab, Gabor
  • Publication
    Métadonnées seulement
    The xenobiotic beta-aminobutyric acid enhances Arabidopsis thermotolerance
    (2008)
    Zimmerli, Laurent
    ;
    Hou, Bi-Huei
    ;
    Tsai, Chia-Hong
    ;
    Jakab, Gabor
    ;
    ;
    Somerville, Shauna
  • Publication
    Accès libre
    Priming by airborne signals boosts direct and indirect resistance in maize
    (2007)
    Ton, Jurriaan
    ;
    D'Alessandro, Marco
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    Jourdie, Violaine
    ;
    Jakab, Gabor
    ;
    Karlen, Danielle
    ;
    ; ;
    Plants counteract attack by herbivorous insects using a variety of inducible defence mechanisms. The production of toxic proteins and metabolites that instantly affect the herbivore's development are examples of direct induced defence. In addition, plants may release mixtures of volatile organic compounds (VOCs) that indirectly protect the plant by attracting natural enemies of the herbivore. Recent studies suggest that these VOCs can also prime nearby plants for enhanced induction of defence upon future insect attack. However, evidence that this defence priming causes reduced vulnerability to insects is sparse. Here we present molecular, chemical and behavioural evidence that VOC-induced priming leads to improved direct and indirect resistance in maize. A differential hybridization screen for inducible genes upon attack by Spodoptera littoralis caterpillars identified 10 defence-related genes that are responsive to wounding, jasmonic acid (JA), or caterpillar regurgitant. Exposure to VOCs from caterpillar-infested plants did not activate these genes directly, but primed a subset of them for earlier and/or stronger induction upon subsequent defence elicitation. This priming for defence-related gene expression correlated with reduced caterpillar feeding and development. Furthermore, exposure to caterpillar-induced VOCs primed for enhanced emissions of aromatic and terpenoid compounds. At the peak of this VOC emission, primed plants were significantly more attractive to parasitic Cotesia marginiventris wasps. This study shows that VOC-induced priming targets a specific subset of JA-inducible genes, and links these responses at the molecular level to enhanced levels of direct and indirect resistance against insect attack.
  • Publication
    Accès libre
    The xenobiotic β-aminobutyric acid enhances Arabidopsis thermotolerance
    (2007)
    Zimmerli, Laurent
    ;
    Hou, Bi-Huei
    ;
    Tsai, Chia-Hong
    ;
    Jakab, Gabor
    ;
    ;
    Somerville, Shauna
    The non-protein amino acid β-aminobutyric acid (BABA) primes Arabidopsis to respond more quickly and strongly to pathogen and osmotic stress. Here, we report that BABA also significantly enhances acquired thermotolerance in Arabidopsis. This thermotolerance was dependent on heat shock protein 101, a critical component of the normal heat-shock response. BABA did not enhance basal thermotolerance under a severe heat-shock treatment. No roles for the hormones ethylene and salicylic acid in BABA-induced acquired thermotolerance were identified by mutant analysis. Using global gene expression analysis, transcript levels for several transcription factors and DNA binding proteins regulating responses to the stress hormone abscisic acid (ABA) were found to be elevated in BABA-treated plants compared with water-treated plants. The role of ABA in BABA-induced thermotolerance was complex. BABA-enhanced thermotolerance was partially compromised in the ABA-insensitive mutant, abi1-1, but was augmented in abi2-1. In an unrelated process, BABA, like ABA, inhibited root growth, and the level of inhibition was roughly additive in roots treated with both compounds. Root growth of both abi1-1 and abi2-1 was also inhibited by BABA. Unexpectedly, abi1-1 and abi2-1 root growth was inhibited more strongly by combined ABA and BABA treatments than by BABA alone. Our results, together with previously published data, suggest that BABA is a general enhancer of plant stress resistance, and that cross-talk occurs between BABA and ABA signalling cascades. Specifically, the BABA-mediated accumulation of ABA transcription factors without concomitant activation of a downstream ABA response could represent one component of the BABA-primed state in Arabidopsis.
  • Publication
    Accès libre
    Interplay between JA, SA and ABA signalling during basal and induced resistance against Pseudomonas syringae and Alternaria brassicicola
    (2007) ;
    Ton, Jurriaan
    ;
    van Doorn, Ronald
    ;
    Jakab, Gabor
    ;
    García-Agustín, Pilar
    ;
    We have examined the role of the callose synthase PMR4 in basal resistance and β-aminobutyric acid-induced resistance (BABA-IR) of Arabidopsis thaliana against the hemi-biotrophic pathogen Pseudomonas syringae and the necrotrophic pathogen Alternaria brassicicola. Compared to wild-type plants, the pmr4-1 mutant displayed enhanced basal resistance against P. syringae, which correlated with constitutive expression of the PR-1 gene. Treating the pmr4-1 mutant with BABA boosted the already elevated levels of PR-1 gene expression, and further increased the level of resistance. Hence, BABA-IR against P. syringae does not require PMR4-derived callose. Conversely, pmr4-1 plants showed enhanced susceptibility to A. brassicicola, and failed to show BABA-IR. Wild-type plants showing BABA-IR against A. brassicicola produced increased levels of JA. The pmr4-1 mutant produced less JA upon A. brassicicola infection than the wild-type. Blocking SA accumulation in pmr4-1 restored basal resistance, but not BABA-IR against A. brassicicola. This suggests that the mutant's enhanced susceptibility to A. brassicicola is caused by SA-mediated suppression of JA, whereas the lack of BABA-IR is caused by its inability to produce callose. A. brassicicola infection suppressed ABA accumulation. Pre-treatment with BABA antagonized this ABA accumulation, and concurrently potentiated expression of the ABA-responsive ABI1 gene. Hence, BABA prevents pathogen-induced suppression of ABA accumulation, and sensitizes the tissue to ABA, causing augmented deposition of PMR4-derived callose.
  • Publication
    Métadonnées seulement
  • Publication
    Métadonnées seulement
  • Publication
    Métadonnées seulement
  • Publication
    Métadonnées seulement
    β-Aminobutyric Acid-Induced Resistance Against Downy Mildew in Grapevine Acts Through the Potentiation of Callose Formation and Jasmonic Acid Signaling
    (2005)
    Hamiduzzaman, Mollah Md.
    ;
    Jakab, Gabor
    ;
    Barnavon, Laurent
    ;
    ;
    β-Aminobutyric acid (BABA) was used to induce resistance in grapevine (Vitis vinifera) against downy mildew (Plasmopara viticola). This led to a strong reduction of mycelial growth and sporulation in the susceptible cv. Chasselas. Comparing different inducers, the best protection was achieved with BABA followed by jasmonic acid (JA), whereas benzo (1,2,3)-thiadiazole-7-carbothionic acid-S-methyl ester (a salicylic acid [SA] analog) and abscisic acid (ABA) treatment did not increase the resistance significantly. Marker genes for the SA and JA pathways showed potentiated expression patterns in BABA-treated plants following infection. The callose synthesis inhibitor 2-deoxy-D-glucose partially suppressed BABA- and JA-induced resistance against P. viticola in Chasselas. Application of the phenylalanine ammonia lyase inhibitor 2-aminoindan-2-phosphonic acid and the lipoxygenase (LOX) inhibitor 5, 8, 11, 14-eicosatetraynoic acid (ETYA) also led to a reduction of BABA-induced resistance (BABA-IR), suggesting that callose deposition as well as defense mechanisms depending on phenylpropanoids and the JA pathways all contribute to BABA-IR. The similar phenotype of BABA- and JA-induced resistance, the potentiated expression pattern of JA-regulated genes (LOX-9 and PR-4) following BABA treatment, and the suppression of BABA-IR with ETYA suggest an involvement of the JA pathway in BABA-IR of grapevine leading to a primed deposition of callose and lignin around the infection sites.