Fig. 3.

Overinduction of iron uptake mechanisms upon iron starvation in plants overaccumulating NA. Col-0 plants (black bars) and K1 plants overaccumulating NA (white bars) were sown for germination on half-strength MS medium and were transferred after 5 d to an iron-deficient medium (no iron added) for 12 d. Real-time RT-PCR determination of FIT1, bHLH38, and bHLH39 (A) or IRT1 and FRO2 (B) transcript levels in roots of iron-starved plants. Error bars represent the SE of four repetitions. IRT1 protein accumulation (C) was detected in a crude protein extract from roots by using an IRT1 affinity-purified peptide antibody. The Coomassie staining shows equal loading. Root Fe(III) chelate reductase activity (D) was determined on a mix of five plantlets. Error bars represent the the SE of four repetitions.