Active invasion of bacteria into living fungal cells

  1. Nadine Moebius
  2. Zerrin Üzüm
  3. Jan Dijksterhuis
  4. Gerald Lackner
  5. Christian Hertweck  Is a corresponding author
  1. Leibniz Institute for Natural Product Research and Infection Biology, Germany
  2. Applied and Industrial Mycology, CBS, Netherlands

Abstract

The rice seedling blight fungus Rhizopus microsporus and its endosymbiont Burkholderia rhizoxinica form an unusual, highly specific alliance to produce the highly potent antimitotic phytotoxin rhizoxin. Yet, it has remained a riddle how bacteria invade into the fungal cells. Genome mining for potential symbiosis factors and functional analyses revealed that a type 2 secretion system (T2SS) of the bacterial endosymbiont is required for the formation of the endosymbiosis. Comparative proteome analyses show that the T2SS releases chitinolytic enzymes (chitinase, chitosanase) and chitin-binding proteins. The genes responsible for chitinolytic proteins and T2SS components are highly expressed during infection. Through targeted gene knock-outs, sporulation assays and microscopic investigations we found that chitinase is essential for bacteria to enter hyphae. Unprecedented snapshots of the traceless bacterial intrusion were obtained using cryo-electron microscopy. Beyond unveiling the pivotal role of chitinolytic enzymes in the active invasion of a fungus by bacteria, these findings grant unprecedented insight into the fungal cell wall penetration and symbiosis formation.

Article and author information

Author details

  1. Nadine Moebius

    Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
    Competing interests
    The authors declare that no competing interests exist.
  2. Zerrin Üzüm

    Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
    Competing interests
    The authors declare that no competing interests exist.
  3. Jan Dijksterhuis

    Applied and Industrial Mycology, CBS, Utrecht, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
  4. Gerald Lackner

    Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
    Competing interests
    The authors declare that no competing interests exist.
  5. Christian Hertweck

    Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
    For correspondence
    christian.hertweck@hki-jena.de
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Thorsten Nürnberger, University of Tübingen, Germany

Version history

  1. Received: April 3, 2014
  2. Accepted: August 29, 2014
  3. Accepted Manuscript published: September 2, 2014 (version 1)
  4. Version of Record published: September 17, 2014 (version 2)

Copyright

© 2014, Moebius et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Nadine Moebius
  2. Zerrin Üzüm
  3. Jan Dijksterhuis
  4. Gerald Lackner
  5. Christian Hertweck
(2014)
Active invasion of bacteria into living fungal cells
eLife 3:e03007.
https://doi.org/10.7554/eLife.03007

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https://doi.org/10.7554/eLife.03007

Further reading

  1. Bacteria and fungal cells join forces to cause rice seedling blight.

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