Evolutionary Divergence of Prophages Detected in Clostridium Taeniosporum

Clostridium taeniosporum is a Gram-positive, nonpathogenic, and anaerobic bacterium that was isolated from Crimean silt. The organism is approximately 98% homologous in 16S rRNA gene to toxigenic Clostridium botulinum phylogenetic Group II strains. It is also unique in that it displays characteristic ribbon-like endospore appendages. Clostridium taeniosporum’s genome is approximately 3, 264.845 Kbs in length, assembled from 18-scaffold sequence reads produced by the GS FLX Titanium genome sequencer. Upon further analysis of these scaffolds, various putative phages that presumably integrated as result of horizontal gene transfer were identified using the PHAge Search Tool, PHAST. To study the evolutionary divergence of phages detected within Bacillus and Clostridum, we identified and downloaded complete phage sequences from the NCBIs GenBank, representing those that infect these two indicated genera of the Firmicutes. We performed a CLUSTALW multi-wise nucleotide alignment (hosted under Geneious v.7.1.6), to construct a phylogenetic tree of Bacillus and Clostridia phage genome sequences both from NCBI and those identified as prophages within the Clostridium taeniosporum genome. Three putative prophages ΦC2, Φ3626, and Geobacillus virus E2, form a cluster, which diverged from the published sequences in the NCBIs GenBank. Results seem to indicate that these sequences presumably diverged after integration into the C. taeniosporum genome. Studying the evolutionary divergence of phages detected within Firmicutes may possibly reveal common genome integration mechanisms, uncover close evolutionary relationships, and may provide further insights into the acquisition of cryptic virulence determinants within the group.