High frequency FP2 donor of Pseudomonas aeruginosa PAO.

After NG mutagenesis an FP2 donor was isolated which exhibited an enhanced conjugational capacity for chromosomal genes. The recombination frequency was increased by two orders of magnitude as compared to the parental strain. In plate matings recombinants arose at a frequency up to 5 X 10(-1) per donor cell. Late markers also recombined efficiently. An Hfr state of the donor strain was supported by (i) the high recombination frequency, (ii) the incompatibility reaction with plasmid pRO271 (= FP2::Tn401) and (iii) the clearcut transfer kinetics in interrupted matings, even for a late marker.