Genomic insights into phage SGP007 reveal a potent therapeutic candidate for targeted control of salmonellosis in poultry.

PURPOSE: This study characterized Salmonella bacteriophage SGP007 to assess its potential as a safe and effective biocontrol or therapeutic agent against pathogenic Salmonella.

RESULTS

Transmission electron microscopy revealed Podoviridae family traits, including an icosahedral head and short, non-contractile tail. Whole-genome sequencing identified a 43,156-base-pair, double-stranded DNA genome with 50.2% G + C content, consistent with Jerseyviruses targeting Salmonella enterica subsp. enterica serovar Gallinarum. Bioinformatic analysis annotated 58 open reading frames, encompassing DNA replication (helicase, methyltransferase), structural assembly (portal, capsid, tail), and host lysis (holin, spanin, endolysin) modules. A single tRNA-Ser-UGA gene was detected, with codon bias compatible with Salmonella's translational system. Critically, the genome lacked lysogenic, virulence, antimicrobial resistance, or toxin-related sequences, confirming its safety. Computational tools (PHASTER, PHACTS, PhageAI) verified an obligately lytic lifecycle. Phylogenetic analysis of the large terminase subunit and genome-wide comparisons (VICTOR, VIPTree) positioned SGP007 within a distinct Jerseyvirus subclade, closely related to Salmonella-specific phages SETP7 and BPS11Q3. VIRFAM classification assigned it to Neck Type 1 - Cluster 3, reflecting its streamlined morphology. The infection cycle follows a typical lytic pathway: receptor binding, DNA ejection, gene expression, replication, virion assembly, and lytic release.

CONCLUSION

This genomic evidence showed that SGP007 was virulent lytic phage, optimized for rapid replication and host lysis without genomic integration.