Iron regulation in P. syringae DC3000

DC3000 cultures were grown under highly controlled conditions and after the addition of iron citrate or sodium citrate to the media. In the cultures supplemented with iron, we found that cell-associated iron increased rapidly while culture densities were not significantly different over 4 hours when compared to cultures with sodium citrate added. Microarray analysis of samples taken from before and after the addition of either sodium citrate or iron citrate identified 386 differentially regulated genes with high statistical confidence. Differentially regulated genes were clustered based on expression patterns observed between comparison of samples taken at different time points and with different supplements. This analysis grouped genes associated with the same regulatory motifs and/or had similar putative or known function. Keywords: iron response, environmental signal, time course Overall design: 5 biological replicates, 3 timepoint: 0h, 0.5h, 4h after addition of iron citrate or sodium citrate to increase final concentration by 50uM