Common gene expression in Medicago truncatula roots in response to Pseudomonas fluorescens colonization, mycorrhiza development and nodulation

Authors

  • L. Sanchez,

    1. UMR INRA 1088/CNRS 5184/U. Bourgogne Plante–Microbe–Environnement, INRA-CMSE, BP 86510, F-21065 Dijon cedex, France;
    2. L. Sanchez and S. Weidmann contributed equally to this paper
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  • S. Weidmann,

    1. UMR INRA 1088/CNRS 5184/U. Bourgogne Plante–Microbe–Environnement, INRA-CMSE, BP 86510, F-21065 Dijon cedex, France;
    2. L. Sanchez and S. Weidmann contributed equally to this paper
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  • L. Brechenmacher,

    1. UMR INRA 1088/CNRS 5184/U. Bourgogne Plante–Microbe–Environnement, INRA-CMSE, BP 86510, F-21065 Dijon cedex, France;
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  • M. Batoux,

    1. UMR INRA 1088/CNRS 5184/U. Bourgogne Plante–Microbe–Environnement, INRA-CMSE, BP 86510, F-21065 Dijon cedex, France;
    2. Present address: Entwicklungsbiologie der Pflanzen WZW, TU Muenchen, Am Hochanger 4, D-85354 Freising/Germany;
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  • D. Van Tuinen,

    1. UMR INRA 1088/CNRS 5184/U. Bourgogne Plante–Microbe–Environnement, INRA-CMSE, BP 86510, F-21065 Dijon cedex, France;
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  • P. Lemanceau,

    1. UMR 1229 INRA-U, Bourgogne Microbiologie et Géochimie du Sol, BP 86510, F-21065 Dijon cedex, France;
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  • S. Gianinazzi,

    1. UMR INRA 1088/CNRS 5184/U. Bourgogne Plante–Microbe–Environnement, INRA-CMSE, BP 86510, F-21065 Dijon cedex, France;
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  • V. Gianinazzi-Pearson

    Corresponding author
    1. UMR INRA 1088/CNRS 5184/U. Bourgogne Plante–Microbe–Environnement, INRA-CMSE, BP 86510, F-21065 Dijon cedex, France;
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Author for correspondence: V. Gianinazzi-PearsonTel: +33 380693155Fax: + 33 380693753Email: Vivienne.Gianinazzi-Pearson@epoisses.inra.fr

Summary

  • • Beneficial rhizosphere microorganisms may share similar molecular steps during root colonization. To test this hypothesis, we compared Medicago truncatula Gaertn. gene expression in roots colonized, or not colonized, by Glomus mosseae BEG12, Pseudomonas fluorescens C7R12 or Sinorhizobium meliloti 2011.
  • • Pseudomonas fluorescens C7R12 formed colonies on the surface of M. truncatula roots and colonized root tissues intercellularly and intracellularly in a way similar to that previously described for other plants.
  • • Semiquantitative reverse transcriptase polymerase chain reaction of a set of 12 mycorrhiza upregulated M. truncatula genes revealed different expression profiles in roots 3 weeks after inoculation with P. fluorescens or S. meliloti. Pseudomonas fluorescens colonization activated seven of the plant genes while nodulated root systems showed increased expression in only three genes and five appeared to be downregulated.
  • • This first report of similar gene induction by a fluorescent pseudomonad and a mycorrhizal fungus in roots supports the hypothesis that some plant cell programmes may be shared during root colonization by these beneficial microorganisms. Less similarity existed in expression of the gene set with nodulation by S. meliloti.

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