Isolation and characterization of a novel Schitoviridae phage VipHU7 that infects Vibrio parahaemolyticus.
In recent years, various bacteriophages that infect Vibrio spp. have been isolated and characterized. However, many characteristics concerning their infection mechanisms remain unknown. Here, we isolated and characterized a novel phage, VipHU7, that infects Vibrio parahaemolyticus. The morphology of VipHU7 was examined using transmission electron microscopy, which demonstrated that it has a short, noncontractile tail characteristic of podoviruses. VipHU7 formed clear plaques with halo zones on a bacterial lawn of V. parahaemolyticus MFS 1101, and host range analysis revealed that it had a limited host range. Analysis of the propagation and one-step growth curve of VipHU7 in liquid medium indicated that its replication rate increases in the presence of divalent cations, which did not affect its adsorption. Genome sequencing revealed that the VipHU7 genome is 76,454 bp long, with a 38.48% GC content and 112 predicted open reading frames. VipHU7 has a genomic structure similar to that of other Varunavirus phages that infect Vibrio spp. VIRIDIC analysis showed that the intergenomic similarity between VipHU7 and Vibrio phage BUCT194 was 83.7%, indicating that VipHU7 is a novel species belonging to the family Schitoviridae and genus Varunavirus.