FIG 2.

Siderophore-mediated iron acquisition requires iucA and iutA. The production of siderophores was detected using colorimetric CAS agar plates (32). (A) For each strain, inoculum was taken from a single colony grown on nutrient agar and streaked down the middle of the CAS plates, followed by incubation for 10 days at 28°C. The radius of the zone of color change was measured at its widest point from the edge of colony growth. (B) The graph represents the mean halo radius from 15 individual plates for each strain. Bars with different letters indicate significance based on a Student t test using P ≤ 0.05. Error bars indicate standard errors of the mean.