Dolichocephalovirinae Phages Exist as Episomal Pseudolysogens Across Diverse Soil Bacteria

Interactions between bacteria and bacteriophages are important for the maintenance of soil communities. In this study, we characterized the giant bacteriophages found within diverse soil bacteria and 14 additional phages isolated directly from soil samples. Based on their genome sizes and genetic composition, we concluded that these phages belong to the <i>Dolichocephalovirinae</i> subfamily. In addition, we used pulsed-field gel electrophoresis to show that the genomes of these phages were present as episomal pseudolysogens in the cytoplasm of their host cells. These findings suggest that episomal phages are important components of soil microbial ecosystems. Understanding the interactions between bacteriophages and bacteria is essential for microbial ecology, as they influence nutrient cycling, community composition, and host evolution. Furthermore, these phage-bacteria dynamics offer potential applications in plant disease control, as bacteriophages could serve as biocontrol agents against soilborne pathogens, promoting sustainable agricultural practices.