The Arabidopsis RTH plays an important role in regulation of iron (Fe) absorption and transport.

(400 μM), the chlorophyll content and ion leakage rate were higher and lower in rth-1 than those of Col-0, respectively. By contrast, the chlorophyll contents and ion leakage rates of RTH overexpression lines were decreased and hastened compared with Col-0, respectively. Fe measurement indicated that the Fe contents of rth-1 were lower than those of Col-0, whereas those of RTH overexpression lines were comparably higher. Gene expression analysis revealed that Fe absorption and transport genes AHA2, IRT1, FIT, FPN1, and YSL1 decreased in rth-1 but increased in RTH overexpression lines compared with Col-0. Additionally, Y2H (yeast two-hybrid) and BiFC (bimolecular fluorescence complementation) assays showed that RTH can physically interact with hemoglobin 1 (HB1) and HB2. All these findings suggest that RTH may play an important role in regulation of Fe absorption, transport, and accumulation in Arabidopsis.