Generalized Transduction in the Phytopathogen Pseudomonas syringae

Abstract

Bacteriophages isolated from culture supernatants of Pseudomonas syringae pv. syringae and from sewage transferred various chromosomal genes to P. syringae PS224. Linkage between arginine and tryptophan loci was demonstrated. The number of transductants recovered per milliliter was not altered appreciably by UV irradiation of selected phage isolates. In addition, the presence of the IncP2 plasmid R38 in a P. syringae PS224 arginine auxotroph did not increase the transduction frequency as it does in Pseudomonas aeruginosa. Increasing the multiplicity of infection of transducing phage Pssy15 from 1 to 10 resulted in up to a 10-fold increase in the number of transductants recovered, although the actual transductional frequency remained about the same. Treatment of transduction mixtures with DNase did not affect transductional frequency.