The sequence of the pYV virulence plasmid from Yersinia enterocolitica strain WA-314 biogroup 1B serotype O:8.

Our laboratory strain Yersinia enterocolitica strain WA-314 biogroup 1B serotype O:8 displayed a different adhesion behavior to host cells compared to other Yersinia strains. To investigate whether this is based on differences in the gene content of the large pYV virulence plasmid which contains the major Yersinia adhesin YadA, we set out to sequence pYV(WA-314). pYV(WA-314) is very similar to pYV127/90, with a notable difference in the length of the Type III secretion system component YscP, which determines the needle length of the system. We found that we could improve the annotation of proteins previously described as "hypothetical" in pYV127/90 and other pYV plasmids, and show that pYV plasmids contain several and seemingly redundant plasmid partitioning and stabilization systems, explaining why these plasmids are not easily lost in laboratory cultures of Yersinia strains.