Biological control of bacterial wilt in Arabidopsis thaliana involves abscissic acid signalling

Authors

  • Dong Xin Feng,

    1. INRA, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
    3. Department of International Cooperation, Chinese Academy of Agricultural Sciences, 12 Zhongguancun South Street, Beijing 100081, China
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    • These authors contributed equally to this work.

  • Céline Tasset,

    1. INRA, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
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    • These authors contributed equally to this work.

  • Mathieu Hanemian,

    1. INRA, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
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    • These authors contributed equally to this work.

  • Xavier Barlet,

    1. INRA, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
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  • Jian Hu,

    1. College of Biological Sciences, China Agricultural University, Beijing 100193, China
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  • Dominique Trémousaygue,

    1. INRA, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
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  • Laurent Deslandes,

    1. INRA, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
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    • These authors contributed equally to this work.

  • Yves Marco

    1. INRA, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR441, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes–Microorganismes (LIPM), UMR2594, Chemin de Borde Rouge F-31326 Castanet-Tolosan, France
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    • These authors contributed equally to this work.


Author for correspondence:
Yves Marco
Tel: +33 5 61 28 55 09
Email: yves.marco@toulouse.inra.fr

Summary

  • Means to control bacterial wilt caused by the phytopathogenic root bacteria Ralstonia solanacearum are limited. Mutants in a large cluster of genes (hrp) involved in the pathogenicity of R. solanacearum were successfully used in a previous study as endophytic biocontrol agents in challenge inoculation experiments on tomato. However, the molecular mechanisms controlling this resistance remained unknown.
  • We developed a protection assay using Arabidopsis thaliana as a model plant and analyzed the events underlying the biological control by genetic, transcriptomic and molecular approaches.
  • High protection rates associated with a significant decrease in the multiplication of R. solanacearum were observed in plants pre-inoculated with a ΔhrpB mutant strain. Neither salicylic acid, nor jasmonic acid/ethylene played a role in the establishment of this resistance. Microarray analysis showed that 26% of the up-regulated genes in protected plants are involved in the biosynthesis and signalling of abscissic acid (ABA). In addition 21% of these genes are constitutively expressed in the irregular xylem cellulose synthase mutants (irx), which present a high level of resistance to R. solanacearum.
  • We propose that inoculation with the ΔhrpB mutant strain generates a hostile environment for subsequent plant colonization by a virulent strain of R. solanacearum.

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