Two distinct sensing pathways allow recognition of Klebsiella pneumoniae by Dictyostelium amoebae

Authors

  • Wanessa C. Lima,

    Corresponding author
    1. Department for Cell Physiology and Metabolism, Centre Medical Universitaire, University of Geneva, Geneva 4, Switzerland
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  • Damien Balestrino,

    1. Laboratoire Microorganismes: Génome et Environnement (LMGE) UMR CNRS 6023, Faculté de Pharmacie, Clermont Université, Clermont-Ferrand, France
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  • Christiane Forestier,

    1. Laboratoire Microorganismes: Génome et Environnement (LMGE) UMR CNRS 6023, Faculté de Pharmacie, Clermont Université, Clermont-Ferrand, France
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  • Pierre Cosson

    1. Department for Cell Physiology and Metabolism, Centre Medical Universitaire, University of Geneva, Geneva 4, Switzerland
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  • The copyright line for this article was changed on 8 April 2015 after original online publication.

Summary

Recognition of bacteria by metazoans is mediated by receptors that recognize different types of microorganisms and elicit specific cellular responses. The soil amoebae Dictyostelium discoideum feeds upon a variable mixture of environmental bacteria, and it is expected to recognize and adapt to various food sources. To date, however, no bacteria-sensing mechanisms have been described. In this study, we isolated a Dictyostelium mutant (fspA KO) unable to grow in the presence of non-capsulated Klebsiella pneumoniae bacteria, but growing as efficiently as wild-type cells in the presence of other bacteria, such as Bacillus subtilis. fspA KO cells were also unable to respond to K. pneumoniae and more specifically to bacterially secreted folate in a chemokinetic assay, while they responded readily to B. subtilis. Remarkably, both WT and fspA KO cells were able to grow in the presence of capsulated LM21 K. pneumoniae, and responded to purified capsule, indicating that capsule recognition may represent an alternative, FspA-independent mechanism for K. pneumoniae sensing. When LM21 capsule synthesis genes were deleted, growth and chemokinetic response were lost for fspA KO cells, but not for WT cells. Altogether, these results indicate that Dictyostelium amoebae use specific recognition mechanisms to respond to different K. pneumoniae elements.

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