Letter

Self-organized patchiness facilitates survival in a cooperatively growing Bacillus subtilis population

  • Nature Microbiology 1, Article number: 16022 (2016)
  • doi:10.1038/nmicrobiol.2016.22
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Abstract

Ecosystems are highly structured. Organisms are not randomly distributed but can be found in spatial aggregates at many scales, leading to spatial heterogeneity or even regular patterns1. The widespread occurrence of these aggregates in many different ecosystems suggests that generic factors intrinsic to the populations—such as interactions between the organisms—play a major role in their emergence1,2. Beyond the emergence of spatial patchiness, its functional consequences remain unclear. Here we show in Bacillus subtilis that cooperative interactions in a spatial environment are sufficient to form self-organized patches. These patches allow for survival even when the microbe density is too low to sustain growth in a well-mixed environment. Decreasing cell mobility leads to more compact patches that enhance this survival advantage but also reduce the overall growth. Our results highlight that even populations lacking specific group-forming mechanisms can nonetheless form spatial patterns that allow for group survival in challenging environments.

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Acknowledgements

We thank D. Kearns, D. Rudner and J. Radeck for generously providing us with strains and plasmids. We thank T. Hugel, I. Bischofs, A. Deutsch, I. Couzin and E. Frey for helpful discussion and all members of the Gore lab for critical reading and discussion of the manuscript. This work was funded by an Allen Distinguished Investigator Award, NSF CAREER Award and NIH New Innovator Award. J.G. is a Pew Scholar in the Biomedical Sciences and a Sloan Fellow.

Author information

Affiliations

  1. Physics of Living Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

    • Christoph Ratzke
    •  & Jeff Gore

Authors

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Contributions

C.R and J.G. designed the research. C.R. performed the research. C.R. and J.G. wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Christoph Ratzke or Jeff Gore.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Discussion, Figures 1–24 and References

Videos

  1. 1.

    Supplementary Video 1

    This video is related to Supplementary Fig. 6. At low agar concentrations (0.22%) in the presence of 0.2% fumarate as a carbon source the bacteria are highly mobile.

  2. 2.

    Supplementary Video 2

    This video is related to Supplementary Fig. 6. At high agar concentrations (1%) in the presence of 0.2% fumarate as a carbon source the bacteria are stalled.