Endocytosis of Xanthomonas campestris pathovar campestris lipopolysaccharides in non-host plant cells of Nicotiana tabacum

Authors

  • Andrea Gross,

    1. University Bielefeld, Faculty of Biology, Department of Genetics, POB 100131, D-33501 Bielefeld, Germany;
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  • Dieter Kapp,

    1. University Bielefeld, Faculty of Biology, Department of Genetics, POB 100131, D-33501 Bielefeld, Germany;
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  • Tim Nielsen,

    1. University Bielefeld, Faculty of Physics, Department of Applied Laser Science, POB 100131, D-33501 Bielefeld, Germany
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  • Karsten Niehaus

    Corresponding author
    1. University Bielefeld, Faculty of Biology, Department of Genetics, POB 100131, D-33501 Bielefeld, Germany;
      Author for correspondence: Karsten Niehaus Tel: +49 521106 5631 Fax: +49 521106 5626 Email: kniehaus@genetik.uni-bielefeld.de
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Author for correspondence: Karsten Niehaus Tel: +49 521106 5631 Fax: +49 521106 5626 Email: kniehaus@genetik.uni-bielefeld.de

Summary

  • • The specific recognition of phytopathogenic bacteria by plant cells is generally mediated by a number of signal molecules. The elicitor-active lipopolysaccharides (LPS) of the phytopathogenic bacterium Xanthomonas campestris pv. campestris (X.c.c) are recognized by its non-host plant Nicotiana tabacum (N.t.).
  • • This LPS was purified and labelled with fluorescein isothiocyanate (FITC) for monitoring the fate of these signal molecules in intact plant cells of tobacco.
  • • In this study we were able to show that the so-labelled LPS rapidly bound to the cell wall and was then internalized into the cells in a temperature- and energy-dependent way. This uptake of LPS could be outcompeted by the addition of an excess of unlabelled LPS. Furthermore, it was blocked by amantadine, an inhibitor of receptor-mediated endocytosis of mammalian cells. Immunolocalization experiments showed for the first time a significant co-localization of the LPS-elicitor with endosomal structures using an anti-Ara6 antibody.
  • • These observations suggest specific endocytosis of LPSX.c.c. into tobacco cells. The possibility for a receptor-mediated endocytosis comparable to the mammalian system will be discussed.

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