FIG. 10.

Expression of SA, Ybt, and Pvd biosynthetic genes by DC3000 and the pchA mutant in high-iron or low-iron cultures. Shown is normalized expression of pchA (A), ybtE (B), and pvdA (C) in wild-type P. syringae pv. tomato DC3000 (black) and the pchA mutant (gray) at 24 hpi in high-iron (with 50 μM FeCl₃) or low-iron medium. pchA (PSPTO2595) is required for SA and Ybt biosynthesis. ybtE (PSPTO2597) is required for Ybt biosynthesis from SA. pvdA (PSPTO2135) is required for Pvd biosynthesis. RNA isolation and qPCR were performed as described in Materials and Methods. Gene expression was normalized to 16S rRNA for each sample and multiplied by 1,000 for ease of presentation. nd, not detected (below detection limit).