Expression of Fe deficiency responsive genes in the iro3 mutants. Fourteen-day-old seedlings grown in Fe-sufficient media were transferred to Fe-sufficient or Fe-deficient media for 4 days. Roots were sampled and used for RNA extraction. The expression of OsIRO2 (a), OsIRO3 (b), OsNAAT1 (c), OsYSL15 (d), OsTOM1 (e), OsYSL2 (f), OsNAS1 (g), OsNAS2 (h), and OsNAS3 (i) was determined by quantitative real-time RT-PCR. OsActin1 was used as the internal standard. Data are given as the means ± SD of three biological replicates. All data were compared with the WT. Significant differences from the mutant and WT are indicated by * p < 0.05, ** p < 0.01, as determined by two-tailed Student’s t test.