Siderophore production comparison between the SO1377 wild-type strain DSP-10 and mutant WG3 on a CAS siderophore testing agar. The chelator-iron (III) complex tints the agar with a rich blue background. The orange halo surrounding the colony indicates the excretion of siderophore and its dimension approximates the amount of siderphore excreted.
Gao et al. BMC Genomics 2006 7:76 doi:10.1186/1471-2164-7-76