Fig. 5

Real-time RT-PCR analyses of gene transcript levels in maize roots. Nineteen-day-old maize plants were grown under Fe sufficiency (+Fe) or Fe deficiency (−Fe); these latter were then supplied with three different Fe-sources: Ferrihydrite, Fe-Citrate or Fe-PS (−Fe/Ferrihydrite, −Fe/Fe-Citrate or –Fe/Fe-PS, respectively). Root samples were harvested after 1, 4 and 24 h from the beginning of the experiment. Analyzed genes: a, ZmYS1 (GRMZM2G156599); b, ZmTOM1 (GRMZM2G063306); c, ZmOPT7 (GRMZM2G421491); d, ZmNRAMP1 (GRMZM2G178190); e, ZmFerritin (GRMZM2G325575); f, ZmPHT1;7 (GRMZM2G112377). Real-time RT–PCR results were validated using two housekeeping genes, ZmGAPDH and ZmTUA, in this figure results normalized on ZmGAPDH are shown. Gene mRNA levels were normalized with respect to the mean transcript level of the housekeeping gene ZmGAPDH; relative changes in gene transcript levels were calculated on the basis of the mean transcript level of ZmGAPDH in Fe-sufficient roots at 1 h (relative gene expression = 1). Data are means of three independent biological replicates + SD (ANOVA Holm–Sidak, P < 0.05, n = 3)