Biodiversity of New Lytic Bacteriophages Infecting Shigella spp. in Freshwater Environment

Bacteriophages, viruses that infect and replicate within prokaryotic cells are the most abundant life forms in the environment, yet the vast majority of them have not been properly reported or even discovered. Almost all reported bacteriophages infecting the family, with being the major subject of studies, have been isolated from wastewater, sewage, and effluent resources. In the present study, we focused on the distribution and biodiversity of phages in an aquatic ecosystem. While no bacteria was recovered from the Yangtze River, three lytic phages were isolated from this ecosystem and were subjected to biological, morphological, and genomic characteristics. Comparative genomics and phylogenetic analyses demonstrated that vB _SflM_004 isolate belongs to family, genus of subfamily, vB_SdyM_006 was classified under the same family, however, it is suggested to be in a new genus under subfamily with some other related bacteriophages. vB_SsoS_008 phage belongs to the family, genus, subfamily. The phages did not harbor any genes involved in the lysogenic cycles and showed a high temperature and pH stability. The biodiversity of the isolated phages highly suggests that continued isolation on non-model members of family is necessary to fully understand bacteriophage diversity in aquatic environments.