Genomic and Structural Analysis of Novel T7-like Bacteriophage phiAS7 Infecting Fish Pathogen Aeromonas salmonicida subsp. salmonicida

Abstract

Bacteriophage (phage) phiAS7 infecting A. salmonicida subsp. salmonicida was isolated from fish farm sediment. The phiAS7 genome comprised of 41,572 bp dsDNA (56.9% G+C ratio) and possessed 147 bp terminal repeats. A total of 51 ORFs were identified and only 32 ORFs showed homology to known T7 or T7-like phages or bacterial proteins. Putative functions of the ORFs formed at least 3 genomic clusters that are involved in DNA metabolism, morphogenesis and lysis module. In the structural analysis, 12 proteins ranging from 15 to 120 kDa were detected and 8 major proteins were sequenced by LC/MS/MS. From these results, 6 partial sequences of structural proteins such as head-to-tail joining protein (ORF38), major capsid protein (ORF36), tail tubular protein A (ORF35), tail tubular protein B (ORF34) and 2 hypothetical proteins (ORF24 and ORF33) were obtained. This is the first report of Aeromonas phage which belongs to Podoviridae, and these results will advance our understanding of the biodiversity of Aeromonas phages.dentified and only 32 ORFs showed homology to known T7 or T7-like phages or bacterial proteins. Putative functions of the ORFs formed at least 3 genomic clusters that are involved in DNA metabolism, morphogenesis and lysis module. In the structural analysis, 12 proteins ranging from 15 to 120 kDa were detected and 8 major proteins were sequenced by LC/MS/MS. From these results, 6 partial sequences of structural proteins such as head-to-tail joining protein (ORF38), major capsid protein (ORF36), tail tubular protein A (ORF35), tail tubular protein B (ORF34) and 2 hypothetical proteins (ORF24 and ORF33) were obtained. This is the first report of Aeromonas phage which belongs to Podoviridae, and these results will advance our understanding of the biodiversity of Aeromonas phages.