Comparative analysis of two phenotypically-similar but genomically-distinct <it>Burkholderia cenocepacia</it>-specific bacteriophages

• Main Authors: Lynch Karlene H, Stothard Paul, Dennis Jonathan J
• Format: Article
• Language: English
• Published: BMC 2012-06-01
• Series: BMC Genomics
• Online Access: http://www.biomedcentral.com/1471-2164/13/223

<p>Abstract</p> <p>Background</p> <p>Genomic analysis of bacteriophages infecting the <it>Burkholderia cepacia</it> complex (BCC) is an important preliminary step in the development of a phage therapy protocol for these opportunistic pathogens. The objective of this study was to characterize KL1 (vB_BceS_KL1) and AH2 (vB_BceS_AH2), two novel <it>Burkholderia cenocepacia</it>-specific siphoviruses isolated from environmental samples.</p> <p>Results</p> <p>KL1 and AH2 exhibit several unique phenotypic similarities: they infect the same <it>B. cenocepacia</it> strains, they require prolonged incubation at 30°C for the formation of plaques at low titres, and they do not form plaques at similar titres following incubation at 37°C. However, despite these similarities, we have determined using whole-genome pyrosequencing that these phages show minimal relatedness to one another. The KL1 genome is 42,832 base pairs (bp) in length and is most closely related to <it>Pseudomonas</it> phage 73 (PA73). In contrast, the AH2 genome is 58,065 bp in length and is most closely related to <it>Burkholderia</it> phage BcepNazgul. Using both BLASTP and HHpred analysis, we have identified and analyzed the putative virion morphogenesis, lysis, DNA binding, and MazG proteins of these two phages. Notably, MazG homologs identified in cyanophages have been predicted to facilitate infection of stationary phase cells and may contribute to the unique plaque phenotype of KL1 and AH2.</p> <p>Conclusions</p> <p>The nearly indistinguishable phenotypes but distinct genomes of KL1 and AH2 provide further evidence of both vast diversity and convergent evolution in the BCC-specific phage population.</p>