The nucleoid-associated protein Fis directly modulates the synthesis of cellulose, an essential component of pellicle–biofilms in the phytopathogenic bacterium Dickeya dadantii

Authors

  • Claire Prigent-Combaret,

    1. Université de Lyon, F-69622, Lyon, France
    2. Université Lyon 1, Villeurbanne, France
    3. CNRS UMR5557 Ecologie Microbienne, Villeurbanne, France
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    • These authors contributed equally to this work.

  • Ouafa Zghidi-Abouzid,

    1. Université de Lyon, F-69622, Lyon, France
    2. Université Lyon 1, Villeurbanne, France
    3. INSA-Lyon F-69621 Villeurbanne, France
    4. CNRS UMR5240 Microbiologie, Adaptation et Pathogénie, France.
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    • These authors contributed equally to this work.

  • Géraldine Effantin,

    1. Université de Lyon, F-69622, Lyon, France
    2. Université Lyon 1, Villeurbanne, France
    3. INSA-Lyon F-69621 Villeurbanne, France
    4. CNRS UMR5240 Microbiologie, Adaptation et Pathogénie, France.
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  • Philippe Lejeune,

    1. Université de Lyon, F-69622, Lyon, France
    2. Université Lyon 1, Villeurbanne, France
    3. INSA-Lyon F-69621 Villeurbanne, France
    4. CNRS UMR5240 Microbiologie, Adaptation et Pathogénie, France.
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  • Sylvie Reverchon,

    1. Université de Lyon, F-69622, Lyon, France
    2. Université Lyon 1, Villeurbanne, France
    3. INSA-Lyon F-69621 Villeurbanne, France
    4. CNRS UMR5240 Microbiologie, Adaptation et Pathogénie, France.
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  • William Nasser

    Corresponding author
    1. Université de Lyon, F-69622, Lyon, France
    2. Université Lyon 1, Villeurbanne, France
    3. INSA-Lyon F-69621 Villeurbanne, France
    4. CNRS UMR5240 Microbiologie, Adaptation et Pathogénie, France.
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Summary

Bacteria use biofilm structures to colonize surfaces and to survive in hostile conditions, and numerous bacteria produce cellulose as a biofilm matrix polymer. Hence, expression of the bcs operon, responsible for cellulose biosynthesis, must be finely regulated in order to allow bacteria to adopt the proper surface-associated behaviours. Here we show that in the phytopathogenic bacterium, Dickeya dadantii, production of cellulose is required for pellicle–biofilm formation and resistance to chlorine treatments. Expression of the bcs operon is growth phase-regulated and is stimulated in biofilms. Furthermore, we unexpectedly found that the nucleoid-associated protein and global regulator of virulence functions, Fis, directly represses bcs operon expression by interacting with an operator that is absent from the bcs operon of animal pathogenic bacteria and the plant pathogenic bacterium Pectobacterium. Moreover, production of cellulose enhances plant surface colonization by D. dadantii. Overall, these data suggest that cellulose production and biofilm formation may be important factors for surface colonization by D. dadantii and its subsequent survival in hostile environments. This report also presents a new example of how bacteria can modulate the action of a global regulator to co-ordinate basic metabolism, virulence and modifications of lifestyle.

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