Genome analysis of Marinobacter phage AS1 suggests its close interactions with host Marinobacter sp.

Abstract

Marinobacter comprises a widespread and ecologically significant genus of marine bacteria with vast metabolic capabilities. However, very few reports on phages infecting this genus exist. In this study, we isolated and characterized a linear dsDNA genome of Marinobacter phage AS1, infecting Marinobacter sp. strain D1S9. This phage, which is a member of the family Podoviridae, has a genome size of ~37 kb and a 57% GC content, with no significant overall similarity to any of the available viral whole genome sequences in the database. The genome, which encodes for 52 protein-coding genes with no tRNA genes, contains 21 protein-coding genes with assigned putative functions. A high degree of recombination events with other members of the order Caudovirales is evident from the mosaic pattern of inheritance of genes encoding major capsid protein, terminase large sub unit, portal protein and integrase. The presence of the integrase gene, DNA methyl transferases and the occurrence of AS1 sequences within the whole genome sequences of some members of the host taxon are suggestive of its intense association with the host.