Occurrence of the strA-strB streptomycin resistance genes in Pseudomonas species isolated from kiwifruit plants.

The occurrence of strA-strB streptomycin-resistance genes within transposon Tn5393 was examined in Pseudomonas syringae pv. actinidiae, P. syringae pv. syringae, and P. marginalis, isolated from kiwifruit plants in Korea and Japan. PCR amplification with primers specific to strA-strB revealed that three of the tested Pseudomonas species harbored these genes for a streptomycin-resistance determinant. Tn5393, containing strA-strB, was also identified with PCR primers designed to amplify parts of tnpA, res, and tnpR. No IS elements were detected within tnpR, nor were they found in the intergenic region between tnpR and strA. Nucleotide sequence analysis indicated that the strA sequence of P. syringae pv. actinidiae contained a single nucleotide alteration at position 593 (CAA-->CGA), as compared to Tn5393a in P. syringae pv. syringae. This resulted in an amino acid change, from Gln to Arg.