Conjugal transfer of E. coli F'lac from Erwinia chrysanthemi to Pseudomonas syringae pv. glycinea and the apparent stable incorporation of the plasmid into the pv. glycinea chromosome.

The E. coli F'lac plasmid was transferred from an Erwinia chrysanthemi Hfr8 donor to a multiply-auxotrophic, rifampicin-resistant Pseudomonas syringae pv. glycinea recipient. Transfer occurred at a frequency of approximately 10(-5)/donor. Stable transconjugants which were able to utilize lactose as the sole carbon source after several transfers would not donate the F'lac plasmid in detectable frequency to other pv. glycinea or E. coli recipients. The plasmid DNA was shown to be integrated into the pv. glycinea chromosome (Fig. 1).