When grown on a solid surface, bacteria form highly organized colonies, yet little is known about the earliest stages of colony establishment. Following Bacillus subtilis colony development from a single progenitor cell, a sequence of highly ordered spatiotemporal events was revealed. Colony was initiated by the formation of leading-cell chains, deriving from the colony center and extending in multiple directions, typically in a "Y-shaped" structure. By eradicating particular cells during these early stages, we could influence the shape of the resulting colony and demonstrate that Y-arm extension defines colony size. A mutant in ymdB encoding a phosphodiesterase displayed unordered developmental patterns, indicating a role in guiding these initial events. Finally, we provide evidence that intercellular nanotubes contribute to proper colony formation. In summary, we reveal a "construction plan" for building a colony and provide the initial molecular basis for this process.
Bibliographical noteFunding Information:
We thank E. Blayvas (Hebrew University) for support during EM analysis the and National BioResource Project National Institute of Genetics, Japan for B. subtilis mutant strains. We are grateful to members of the S.B.-Y. laboratory and G. Bachrach, I. Rosenshine, and A. Taraboulos (Hebrew University) for valuable comments. This work was supported by a European Research Council Advance Grant (339984) and by the Israel Science Foundation (327/11) awarded to S.B.-Y. G.B.M.M. was supported by the Israeli Council for Higher Education PBC-outstanding postdoctoral fellowship.
© 2016 The Authors.