Microarray were done on 4 independent cultures. PA01 was grown for 6 hours to late log growth phase (OD600 0.9-1.0) in liquid BM2-swarming media under shaking conditions(swimming) or for 18 hours at 37C on BM2-swarming plate containing 0.5% (w/v) agar and 0.1% casamino acids. Cells were harvested either by centrifugation(swimming) or by a sterile inoculating loop (swarming) and were resuspended n BM2-swarming media supplement with RNAprotect reagent (Qiagen)