Figure 2.

RNA blot analysis of hrp and avr transcripts in Pst DC3000 and hrp mutants. hrp gene operons, named by their first genes, are diagrammed at the top. The directions of transcription are indicated by arrows. The hrpW gene is linked to the core hrp cluster, whereas avrPto is not. Conditions for bacterial growth and RNA analysis are described in Materials and Methods. The genes indicated on the left were used as probes. The 23S rRNA visualized after ethidium bromide staining was used as loading control. RNA was isolated from bacteria grown in hrp-repressing LB or hrp-inducing minimal medium (MM). *, The hrcC and hrcZ genes are located within the hrpF and hrpA gene operons, respectively. See ref. 39 for a more detailed description of the P. syringae hrp gene cluster.