Unusual relationship of IncB/O and IncZ plasmids revised.

Plasmid incompatibility is the inability of two plasmids to be stably maintained in one cell. Dislodgement is a form of incompatibility, described as an imperfect reproduction manifesting in rapid exclusion of a resident plasmid after superinfection. The relationship between plasmids IncB/O and IncZ was initially referred to as dislodgement. Further research showed similar results yet reached the conclusion that IncB/O and IncZ plasmids are incompatible. In this manuscript we revise the relationship between IncB/O and IncZ plasmids. We performed dislodgement testing by electroporating IncB/O and IncZ plasmids in a bacterial cell and checked their stability. Stability tests showed that the IncB/O plasmid was exclusively and almost completely lost from the heteroplasmid E. coli population. Our data suggests that the relationship between IncB/O and IncZ plasmids should be considered partitioning-based incompatibility.