Sequence and comparative genomic analysis of lactococcal bacteriophages jj50, 712 and P008: Evolutionary insights into the 936 phage species

The complete genome sequences of three lactococcal 936-type bacteriophages, 712, jj50 and P008, were determined. Comparative genomic analysis of these phages with the previously sequenced 936-type phages, ski and bIL170, reveals a strict conservation of the overall genetic organization of this geographically diverse phage group. Genetic divergence was mainly observed in the early expressed region of the phage genomes, where a number of deletions, exchanges and insertions appear to have occurred. These genetic differences may be responsible for the observed differential sensitivity to the lactococcal DNA injection blocking protein, Sie₂₀₀₉, and the abortive infection system, AbiA.