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bioRxiv · 10.64898/2026.08.23.746533

A phage communication peptide alters Bacillus subtilis colony development and promotes sporulation

Hagbi-Lazar, B.-E.·Levi, Z.·Shema-Mizrachi, M.·Suissa, R.·Tik, Z.·Uzi-Gavrilov, S.·Holoidovsky, L.·Bendori, S. O.·Eldar, A.·Meijler, M. M.
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Abstract

Temperate Bacillus phages use arbitrium peptides to coordinate lysis-lysogeny decisions, but whether the mature communication peptide can be sensed directly by Bacillus subtilis and affect its physiology and behavior is unknown. Here we show that the {varphi}3T arbitrium peptide SAIRGA elicits a sequence- and stereochemistry-dependent response in Bacillus subtilis that is strongly expressed in surface-grown colony biofilms but is not accompanied by comparable changes in planktonic growth or static-liquid pellicle morphology. The response persists in the absence of AimR, the canonical arbitrium receptor. Within colonies, SAIRGA alters spatial PtapA activity and increases heat-resistant spore formation without increasing total viable cell yield. Untargeted metabolomics reveals broad dose-dependent remodeling that tracks peptide activity, while program-level proteomics independently converges on late-sporulation and mature-spore-associated states. This study highlights how a phage-derived peptide may act as a signal, enabling the host to pivot toward a survival-focused developmental state.

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Hagbi-Lazar, B.-E., Levi, Z., Shema-Mizrachi, M., Suissa, R., Tik, Z., Uzi-Gavrilov, S., Holoidovsky, L., Bendori, S. O., Eldar, A., Meijler, M. M.. 2026-08-24. A phage communication peptide alters Bacillus subtilis colony development and promotes sporulation. https://doi.org/10.64898/2026.08.23.746533

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