FIGURE 4.

Complementation of the Arabidopsis ${\mathrm{NH}}_{\mathrm{4}}^{\mathrm{+}}$ uptake defective mutant qko by TaAMT1;1b. TaATM1;1b was expressed in the qko background under the control of the AtAMT1;1 promoter. Expression levels of TaATM1;1b were monitored in the TaATM1;1b transgenic plant roots (#1, #2, and #4), and AtActin2 was used as a loading control (A). Methyl-ammonium (MeA) dependent growth of qko, qko+AtAMT1;1, and qko+TaAMT1;1b was photographed. Three-day-old seedlings grown in 1 mM KNO₃ containing modified 0.5× MS medium were transferred to the same medium containing either 0 or 10 mM MeA. Plant growth was photographed after 4 days (B). Total fresh weight of the seedlings (30 seedling for each line) shown in (B) was measured. Significant differences between qko and qko+AtAMT1;1 or qko+TaAMT1;1b were assessed (C). ${\mathrm{NH}}_{\mathrm{4}}^{\mathrm{+}}$ contents from the roots of 7-day-old qko, qko+AtAMT1;1, and qko+TaAMT1;1b plants grown in 0.5× MS medium were measured (D). Significant differences at P < 0.05 level are indicated by different letters.