Iron concentration was altered for RC2-SM, RC2-Δall1, H99-wt, H99-Δall1 and reconstituted strains under low iron conditions (A, B) and in response to ferric chloride (C, D). Differences in exo-PS structure of H99-wt and H99-Δall1 mutant affect expression of iron transport related genes. FTR1, FRE1, CNM02430, CNM02420, CNH01230, CNG00950, CIG1, and CNB00400 were up-regulated in H99-Δall1 (black bars) and in H99-wt cells (white bars) by addition of 40μg/ml mutant exo-PS. In contrast, addition of H99-wt exo-PS to H99-Δall1 cells (striped bars) resulted in significant down-regulation of iron transport related genes (E).