Host range, entry exclusion, and incompatibility of Pseudomonas aeruginosa FP plasmids

The transposons Tn501, Tn7, and Tn1 were used to mark 20 FP plasmids of Pseudomonas aeruginosa which have previously been characterized on the basis of their host chromosome mobilizing ability (Cma) and their contribution to error-prone DNA repair. These transpositional derivatives were used to study the host range, entry exclusion, and incompatibility systems of these plasmids. Many of these plasmids were transferable to Pseudomonas putida, Pseudomonas glycinea, and Pseudomonas maltophilia. Where tested, these plasmids were retransferable back to P. aeruginosa from P. putida and their passage through the latter had not altered Cma. Their transmissibility to other Pseudomonas species will enable their use as Cma plasmids in those bacteria. Most of the FP plasmids were also transferable to enteric bacteria such as the naturally restriction-deficient Escherichia coli C and a restriction-deficient mutant of Klebsiella pneumoniae. However, in these bacteria the plasmids were extremely unstable. The FP plasmids were found to belong to five entry exclusion systems and four incompatibility groups in P. aeruginosa.