FIGURE 6.

Deletion of the siderophore synthesis gene cluster (ΔiucA_iucC/iucB/iucD) led to impaired growth under iron stress conditions. (A) Organization of the iucA/iucC, iucB and iucD gene cluster was shown as the wide solid arrows (up panel). The locations and amplification directions of the primers were indicated using the thin arrows (low panel). hp, hypothetic protein; ddc, putative L-2,4-diaminobutyrate decarboxylase. (B) Detection of gene fragments of iucA/iucC, iucB and iucD genes in the WT and the mutant. Lane M, molecular marker. WT, wild-type; Mut, mutant. (C) The growth curve of WT and siderophore synthesis mutant in high-iron and low iron media. WT−, wild-type grown in the low iron media; Mut−, mutant grown in the low iron media; WT+, wild-type grown in the high-iron media; Mut+, mutant grown in the high-iron media.