The impact of iron supply on oxidative stress resistance of A. fumigatus. A. fumigatus wild type and ΔsidA strains were point-inoculated on minimal medium plates reflecting different iron supply with and without stressors leading to oxidative stress (H2O2 and the redox cyclers paraquat and menadione) or BPS, a ferrous iron-specific chelator, which inactivates reductive iron assimilation . Growth was scored after incubation for 48 h at 37 °C. The effect of H2O2 in the presence of BPS is not shown because H2O2 interferes with BPS function. The A. fumigatus ΔsidA mutant  lacks siderophore biosynthesis, which results in decreased iron uptake and decreased resistance to iron starvation. As BPS blocks the growth of ΔsidA , this mutant was not analyzed in the presence of BPS. Compared to iron sufficiency (+Fe), iron deprivation (-Fe/BPS) increased the oxidative stress accessibility of the wild type strain (marked by yellow dots); compared to the wild-type strain, SidA-deficiency increased oxidative stress accessibility on +Fe medium (marked by green dots) and -Fe medium (marked by blue dots).