Isolation and genomic characterization of a Teetrevirus phage infecting Klebsiella quasipneumoniae with a putative SAMase gene.

Phages regulate bacterial populations in engineered ecosystems. However, wastewater associated phage lineages remain uncultured and poorly characterized. Here, we describe vB_KquP_T1, a bacteriophage infecting Klebsiella quasipneumoniae and exhibiting a lytic growth phenotype, isolated from urban wastewater. Genome-based phylogenomic analyses revealed that vB_KquP_T1 represents a distinct species-level lineage within the Teetrevirus of the Autotranscriptaviridae, closely related to uncultured viral genomes. Metagenomic recruitment from 234 global wastewater datasets reveals that vB_KquP_T1-like phages are widespread, with pronounced regional variation. Notably, the vB_KquP_T1 genome encodes a putative S-adenosyl-L-methionine hydrolase (SAMase)-like protein. Structural modeling and comparative analysis revealed a conserved structural architecture, while molecular docking predicted potential interactions with SAM-related ligands. These findings link an uncultured viral lineage to a cultivated representative and support the conservation of SAM metabolism-related auxiliary genes across tailed phages.