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bioRxiv · 10.1101/2025.05.06.652435

Evolutionary consequences of bacterial resistance to a flagellotropic phage

Antani, J. D.·Theroux, A.·Emonet, T.·Turner, P. E.
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Abstract

Bacteria can evolve resistance to bacteriophage attack via mutations that alter phage receptors on the cell surface. Flagellotropic phages bind to motility-enabling flagella, creating an evolutionary trade-off, since losing flagellar function reduces fitness in many environments. We experimentally evolved Escherichia coli populations under selection by flagellotropic phage (chi), on soft-agar swim plates which favor motility. Whole genome sequencing revealed early emergence of non-motile mutants with disrupted motility-genes, followed by motile mutants with flagellin gene mutations. Swim-plate assays and single-cell tracking showed variable motility effects among resistant mutants, with some faster and others slower than ancestors. Increased tumble bias suggested altered flagellar rotation. Kinase-response in the upstream chemotaxis pathway was also remodeled in -resistant mutants. Our findings demonstrate that evolved phage-resistance can cause motility to trade-off or trade-up, revealing diverse evolutionary outcomes under combined selection pressures. TeaserEvolution redesigns bacterial swimming and navigation to escape viruses while maintaining motility in complex environments.

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Antani, J. D., Theroux, A., Emonet, T., Turner, P. E.. 2025-05-10. Evolutionary consequences of bacterial resistance to a flagellotropic phage. https://doi.org/10.1101/2025.05.06.652435

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