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Mauch-Mani, Brigitte

Nom
Mauch-Mani, Brigitte
Affiliation principale
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Ancien.ne collaborateur.trice
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https://libra.unine.ch/handle/123456789/304

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  • Publication
    Accès libre
    β-Aminobutyric Acid-induced Resistance in Plants
    (2001)
    Jakab, Gabor
    ;
    Cottier, Valérie
    ;
    Toquin, Valérie
    ;
    Rigoli, Ghislaine
    ;
    Zimmerli, Laurent
    ;
    Métraux, Jean-Pierre
    ;
    Mauch-Mani, Brigitte 
    The broad sprectrum protective effect of the non-protein amino acid β-aminobutyric acid (BABA) against numerous plant diseases has been well-documented in the literature. Here, we present an overview of BABA-induced protection in various pathosystems. Contriidictory reports concerning the mechanism of action underlying this type of protection incited us to take advantage of Arabidopsis/pathogen interactions as model systems to investigate the action of BABA at the genetic and molecular level. We present evidence that the protective effect of BABA is due to a potentiation of natural defense mechanisms against biotic and abiotic stresses. In order to dissect the pathways involved in potentiation by BABA describe the use of a mutational approach based on BABA-induced female sterility in Arabidopsis.
  • Publication
    Accès libre
    Manipulation of salicylate content in Arabidopsis thaliana by the expression of an engineered bacterial salicylate synthase
    (2001)
    Mauch, Felix
    ;
    Mauch-Mani, Brigitte 
    ;
    Gaille, Catherine
    ;
    Kull, Beatriz
    ;
    Haas, Dieter
    ;
    Reimmann, Cornelia
    Salicylic acid (SA) plays a central role as a signalling molecule involved in plant defense against microbial attack. Genetic manipulation of SA biosynthesis may therefore help to generate plants that are more disease-resistant. By fusing the two bacterial genes pchA and pchB from Pseudomonas aeruginosa, which encode isochorismate synthase and isochorismate pyruvate-lyase, respectively, we have engineered a novel hybrid enzyme with salicylate synthase (SAS) activity. The pchB-A fusion was expressed in Arabidopsis thaliana under the control of the constitutive cauliflower mosaic virus (CaMV) 35S promoter, with targeting of the gene product either to the cytosol (c-SAS plants) or to the chloroplast (p-SAS plants). In p-SAS plants, the amount of free and conjugated SA was increased more than 20-fold above wild type (WT) level, indicating that SAS is functional in Arabidopsis. P-SAS plants showed a strongly dwarfed phenotype and produced very few seeds. Dwarfism could be caused by the high SA levels per se or, perhaps more likely, by a depletion of the chorismate or isochorismate pools of the chloroplast. Targeting of SAS to the cytosol caused a slight increase in free SA and a significant threefold increase in conjugated SA, probably reflecting limited chorismate availability in this compartment. Although this modest increase in total SA content did not strongly induce the resistance marker PR-1, it resulted nevertheless in enhanced disease resistance towards a virulent isolate of Peronospora parasitica. Increased resistance of c-SAS lines was paralleled with reduced seed production. Taken together, these results illustrate that SAS is a potent tool for the manipulation of SA levels in plants.