1985 Volume 51 Issue 4 Pages 426-434
The conjugational proficiency and replicative ability of plasmid pBPW1, found in Pseudomonas syringae pv. tabaci BR2, in P. syringae pathovars mori, atropurpurea, tabaci, eriobotryae and glycinea were examined. The plasmid was transferred and maintained as an autonomous replicon in ca. 40% of the strains at frequencies ranging from ca. 10-6 to 100% per recipient. These strains also expressed donor ability for pBPW1, with transfer frequencies ranging from 10-6 to 100%. In other strains the plasmid was apparently transferred but unable to replicate. This behaviour suggests that pBPW1 is potentially useful as a suicidal carrier for transposon mutagenesis in these strains. With one exception, the bacteriological properties of transconjugants were identical to those of the wild type recipient strains. The exception was pv. atropurpurea NIAES 1309 transconjugants, the majority of which aggregated in King's B broth and had altered serological properties. These findings suggest that pBPW1 carries a gene(s) responsible for cell aggregation and antigen alteration. However, the gene expression depends on the host's genetic background and does not occur in all hosts.
