The role of FIT in exogenous Suc regulation of Fe deficiency responses in roots. A, Comparison of FIT expression between Col-0 plant and the 35S::SUC2 transgenic plants. B, Effects dark treatment on FIT expression in Col-0 plant. C, Comparison of FIT expression between Col-0 plants and the suc2-5 mutants. D-F, Effects of exogenous Suc on FCR activity and the expression of FRO2 and IRT1 in Col-0 plants and the fit mutants. For the experiments in A-C, the plants were treated as in Figures 5, 3, and 4, respectively. For the experiments in D-F, the plants were treated as in Figure 2C. Gene expression was analyzed by real-time qPCR. Transcript level of UBQ10 was used as an internal control. Data are means ± sd (n = 5-7). Different letters indicate significant differences among treatments with in a genotype (one-way ANOVA, P < 0.05). An asterisk shows a significant genotype by treatment interaction (two-way ANOVA, P < 0.05).