FIG. 1.

Generation of carrier-state P. syringae cells containing φ6 bla. (A) Schematic diagram of the technology used (see text for details). (B) Agarose gel electrophoresis of total RNAs from the following strains: K, KAN-resistant HB10Y(φ6-npt); A0, AMP-resistant HB10Y(φ6-bla); HB, noninfected HB10Y. Lane φ6, dsRNA segments L, M, and S extracted from the wt φ6 (positions are indicated on the left, along with the positions of P. syringae 23S and 16S rRNAs); lane Mk, dsDNA markers. Marker lengths in kilobase pairs are shown on the right. The arrowhead shows the new segment, M-bla, which appears in AMP-resistant cells. (C) RT-PCR analysis with npt- and bla-specific primers was performed with RNAs from HB10Y(φ6-npt) (K) and HB10Y(φ6-bla) (A0). The reverse transcription step was omitted in reactions 2 and 5. Different PCR primers were used as specified under the panel. The positions of the npt- and bla-specific PCR fragments are marked on the right. dsDNA marker (Mk) lengths are shown on the left.