Transduction of a Plasmid with an Inserted R4 Phage DNA Fragment in Streptomyces lividans

A Streptomyces plasmid, pR4C2, with an inserted DNA fragment of R4 phage, was encapsidated into R4 phage particles in vivo and transduced to Streptomyces lividans at 3 ×10^?6CFIJ/PFU. Formation of transducing phage was dependent on the inserted R4 DNA, and some of the transducing phages had larger DNA than R4 phage. A possible transduction mechanism through plasmid-phage cointegrate formation in vivo is discussed.