R68.45 plasmid mediated conjugation in Thiobacillus A2.

Plasmid R68.45 classified into the IncP-1 group which is characterized by a broad host range, was transferred from Pseudomonas aeruginosa PA025 or Escherichia coli into Thiobacillus A2 by conjugation. The R plasmid was stably maintained in Thiobacillus A2 but only neomycin/kanamycin resistance was fully expressed in the new host. Conjugational transfer of R68.45 between different Thiobacillus A2 strains was observed. R plasmid mediated transfer of chromosomal markers has been demonstrated.