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Published on: December 14, 2019
Do plasmid-dependent phages enable the survival of costly plasmids?
Jonathon L Yuly1, Matthew Avallone2, Lawrence Abad2
1Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540.
Biorxiv : the Preprint Server for Biology
|June 12, 2026
Summary
Plasmids can be lost by bacteria, but phages can help costly plasmids persist. Phage predation maintains plasmids at low levels, preventing extinction and enabling benefits when needed.
Area of Science:
- Microbiology
- Evolutionary Biology
- Genetics
Background:
- Plasmids provide bacteria with auxiliary genes for environmental adaptation, like antibiotic resistance.
- Plasmid loss can be beneficial if costs outweigh temporary advantages, but can lead to extinction without sustained selection.
- High plasmid costs can make bacterial hosts uncompetitive, hindering plasmid survival.
Purpose of the Study:
- To investigate mechanisms enabling the survival of costly, occasionally beneficial plasmids in bacterial populations.
- To explore the role of plasmid-dependent phages in maintaining plasmid persistence.
Main Methods:
- Utilized population modeling to simulate bacterial-plasmid-phage dynamics.
- Analyzed the impact of phage predation on plasmid abundance and host competitiveness.
Main Results:
- Demonstrated that plasmid-dependent phages can maintain plasmids at low, non-zero abundance.
- Showed that phage predation effectively neutralizes the population-level cost of plasmids, extending their persistence.
- Observed that plasmids spread and shift to vertical transmission when they become beneficial.
Conclusions:
- Plasmid-dependent phages offer a novel solution for the survival of costly plasmids in bacterial communities.
- This phage-mediated mechanism allows plasmids to persist through periods of low benefit and rapidly spread when advantageous.
- The interplay between phages, plasmids, and bacteria highlights a unique evolutionary strategy for maintaining genetic diversity.
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