Bacteriophage-host interactions in Streptococcus thermophilus and their impact on co-evolutionary processes

This review provides an overview of the current knowledge of interactions and co-evolution of Streptococcus thermophilus and its infecting phages. Bacteriophages (or phages) represent a persistent threat to the success and reliability of food fermentation processes. Recent reports of phages that infect Streptococcus thermophilus have highlighted the diversification of phages of this species. Phages of S. thermophilus typically exhibit a narrow range, a feature that is suggestive of diverse receptor moieties being presented on the cell surface of the host. Cell wall polysaccharides, including rhamnose-glucose polysaccharides and exopolysaccharides have been implicated as being involved in the initial interactions with several phages of this species. Following internalization of the phage genome, the host presents several defences, including CRISPR-Cas and restriction and modification systems to limit phage proliferation. This review provides a current and holistic view of the interactions of phages and their S. thermophilus host cells and how this has influenced the diversity and evolution of both entities.

Automated summary

This review provides a comprehensive overview of the interactions and co-evolution of Streptococcus thermophilus and its infecting phages. The diversity of phages that infect S. thermophilus has been highlighted, suggesting the presence of various receptor moieties on the host cell surface. Cell wall polysaccharides are implicated in the initial interactions, and host defenses such as CRISPR-Cas and restriction and modification systems limit phage proliferation. This review offers insight into the interactions between phages and S. thermophilus host cells and their impact on their diversity and evolution.