Comparative Genomics of Six Lytic Phages from the Southwest United States.

Background: Despite their importance to microbial dynamics involving , we have a limited understanding of the diversity of phages that can lyse this model organism.

Materials And Methods: Phages were isolated from soil samples collected from various sites in the southwest U.S. deserts on a wild strain. Their genomes were assembled, characterized, and bioinformatically compared.

Results: Six Siphoviruses with high nucleotide and amino acid similarity to each other (>80%) but very limited similarity to phages currently in GenBank were isolated. These phages have double-stranded DNA genomes (55,312 to 56,127 bp) with 86-91 putative protein coding genes, and a low GC content. Comparative genomics reveal differences in loci encoding proteins that are putatively involved in bacterial adsorption with evidence for genomic mosaicism and a possible role for small genes.

Conclusions: A comparative approach provides insights into phage evolution, including the role of indels in protein folding.