Fig. 2

Iron-dependent essential genes have increased number of insertion sites and read counts under iron-restricted conditions. A genome-saturating library of S. Typhimurium Tn5 mutants was selected in LB medium (iron-replete; LB-III) and LB medium supplemented with Dip (iron-restricted; Dip 250 and Dip400). The resulting mutant pools were subjected to Tn-seq analysis to identify essential genes. Mutant fitness in Dip400 increased significantly in comparison to LB-III for the 33 genes shown here (P < 0.05). I and R indicate the number of unique insertion sites and total read counts, respectively. Mutant fitness is expressed in Log₂ fold change of the sequence read counts in Dip400 in comparison to LB-III