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, sk1 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, Sie(2009), and the abortive infection system, AbiA.