The symbiotic transcription factor MtEFD and cytokinins are positively acting in the Medicago truncatula and Ralstonia solanacearum pathogenic interaction

Authors

  • Sandra Moreau,

    1. INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
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    • These authors contributed equally to this work.
  • Justine Fromentin,

    1. INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
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    • These authors contributed equally to this work.
  • Fabienne Vailleau,

    1. INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
    3. Université de Toulouse, INP, ENSAT, Castanet Tolosan, France
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  • Tatiana Vernié,

    1. INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
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  • Stéphanie Huguet,

    1. Unité de Recherche en Génomique Végétale (URGV), INRA, UMR 1165, Université d'Evry Val d'Essonne, ERL CNRS 8196, Evry Cedex, France
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  • Sandrine Balzergue,

    1. Unité de Recherche en Génomique Végétale (URGV), INRA, UMR 1165, Université d'Evry Val d'Essonne, ERL CNRS 8196, Evry Cedex, France
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  • Florian Frugier,

    1. Institut des Sciences du Végétal (ISV), Centre National de la Recherche Scientifique (CNRS), Gif-sur-Yvette, France
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  • Pascal Gamas,

    1. INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
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  • Marie-Françoise Jardinaud

    Corresponding author
    1. INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, France
    2. CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, France
    3. Université de Toulouse, INP, ENSAT, Castanet Tolosan, France
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Summary

  • A plant–microbe dual biological system was set up involving the model legume Medicago truncatula and two bacteria, the soil-borne root pathogen Ralstonia solanacearum and the beneficial symbiont Sinorhizobium meliloti.
  • Comparison of transcriptomes under symbiotic and pathogenic conditions highlighted the transcription factor MtEFD (Ethylene response Factor required for nodule Differentiation) as being upregulated in both interactions, together with a set of cytokinin-related transcripts involved in metabolism, signaling and response. MtRR4 (Response Regulator), a cytokinin primary response gene negatively regulating cytokinin signaling and known as a target of MtEFD in nodulation processes, was retrieved in this set of transcripts.
  • Refined studies of MtEFD and MtRR4 expression during M. truncatula and R. solanacearum interaction indicated differential kinetics of induction and requirement of central regulators of bacterial pathogenicity, HrpG and HrpB. Similar to MtRR4, MtEFD upregulation during the pathogenic interaction was dependent on cytokinin perception mediated by the MtCRE1 (Cytokinin REsponse 1) receptor.
  • The use of M. truncatula efd-1 and cre1-1 mutants evidenced MtEFD and cytokinin perception as positive factors for bacterial wilt development. These factors therefore play an important role in both root nodulation and root disease development.

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