Iron is essential for all organisms. Bacteria have devolved sophisticated systems to maintain intracellular iron homeostasis. FpvCDEF(PA2407-2410) has been reported as an ABC transporter involved in pyoverdine-Fe uptake which does not affect growth under iron-limiting condition, when it is deleted in PAO1. In this study, we proved that fpvCDEF and fpvWXYZ(PA2403-2406) constituted an ABC transporter complex containing two operons: fpvWXYZCDE and fpvF. The operon fpvWXYZCDE was regulated by iron negatively and the single gene operon fpvF was constitutively expressed. Inactivation of any one of the components, fpvW, fpvC, fpvD, fpvE, and fpvF, led to increased expression of fpvWXYZCDE suggesting that each component of fpvWXYZCDEF could be involved in iron uptake. The ABC transporter complex encoded by fpvWXYZCDEF plays important roles in growth, oxidative stress resistance, and virulence, since the deletion of fpvWXYZCDEF resulted in defective growth, increased sensitivity to H2O2, and decreased virulence compared with PAO1(Delta fpvCDEF) and the wild type PAO1 under iron-limiting condition.
