Global alignment of chromosomes of completely sequenced P. polymyxa strains. The local collinear block (LCB) plot was generated using the progressiveMauve algorithm using default parameters. The name of the strain represented is listed below each LCB plot. Global alignments are visualized as LCBs, which represent regions of chromosomal similarity among strains. Six LCBs were identified in the four P. polymyxa strains genomes and are coloured according to homology to LCBs of other strains. Regions without colour both within and between LCBs represent the presence of strain-specific sequence. LCBs drawn below the horizontal correspond to inversions.