Introduction of Bacteriophage Mu into Pseudomonas solanacearum and Rhizobium meliloti using the R Factor RP4

SUMMARY: Phage Mu-1 and a thermoinducible derivative, Mu-1 cts 62 were inserted into the broad host range R factor RP4. These hybrid plasmids were transferred by conjugation to a phytopathogenic bacterium Pseudomonas solanacearum GM11000 and a legume-root nodule bacterium Rhizobium meliloti 2011. The Mu genome is transcribed and translated in these new hosts: P. solanacearum (RP4::Mu cts) cultures have a spontaneous production of about 5 x 10⁵ plaque-forming units ml^-1 which is similar to the frequency of spontaneous Mu production in E. coli; the Mu production of R. meliloti is lower (about 10² plaque-forming units ml^-1).