Molecular Insights into Bacteriophage Evolution toward Its Host

• Main Authors: Marina de Leeuw, Maayan Baron, Oshrit Ben David, Ariel Kushmaro
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Viruses
• Subjects: bacteriophage; bacteria; evolution; mutation; speciation; tubular protein B
• Online Access: https://www.mdpi.com/1999-4915/12/10/1132

Bacteriophages (phages), viruses that infect bacteria, are considered to be highly host-specific. To add to the knowledge about the evolution and development of bacteriophage speciation toward its host, we conducted a 21-day experiment with the broad host-range bacteriophage <i>Aquamicrobium</i> phage P14. We incubated the phage, which was previously isolated and enriched with the Alphaproteobacteria <i>Aquamicrobium</i> H14, with the Betaproteobacteria <i>Alcaligenaceae</i> H5. During the experiment, we observed an increase in the phage’s predation efficacy towards <i>Alcaligenaceae</i> H5. Furthermore, genome analysis and the comparison of the bacteriophage’s whole genome indicated that rather than being scattered evenly along the genome, mutations occur in specific regions. In total, 67% of the mutations with a frequency higher than 30% were located in genes that encode tail proteins, which are essential for host recognition and attachment. As control, we incubated the phage with the Alphaproteobacteria <i>Aquamicrobium</i> H8. In both experiments, most of the mutations appeared in the gene encoding the tail fiber protein. However, mutations in the gene encoding the tail tubular protein B were only observed when the phage was incubated with <i>Alcaligenaceae</i> H5. This highlights the phage’s tail as a key player in its adaptation to different hosts. We conclude that mutations in the phage’s genome were mainly located in tail-related regions. Further investigation is needed to fully characterize the adaptation mechanisms of the <i>Aquamicrobium </i>phage P14.