Fig. 5

AspA is required for iron acquisition. a Effect of DPD supplementation on C48–1 and △aspA::kan growth under aerobic conditions. The final OD₆₀₀ values were determined after incubation in TSB in different iron-limited conditions at 16 h. b The growth curves of C48–1, △aspA::kan, C△aspA::kan and △aspA::kan (pAL99S) were measured at 37° in TSB containing 150 μM DPD under aerobic conditions. c Utilization of iron sources by C48–1 and △aspA::kan, C△aspA::kan and △aspA::kan (pAL99S). Wild-type and aspA mutant strains were inoculated in TSB containing 150 μM DPD supplemented with FeCl₃ or FeSO₄ under aerobic conditions. The final OD₆₀₀ values were determined after 16 h. d Transcription levels of the aspA gene in C48–1, △aspA::kan and C△aspA::kan in response to different iron-limited conditions. Data analyzed by Student’s t-test. * P < 0.05; ** P < 0.01 and NS for P>0.05