Fig 7. The nitrate response of XTH9 is altered in afb3-1, slr-1 mutant background and XTH9 is still regulated by nitrate in NR-null nia1nia2 mutant.

(A) WT (Col-0) and afb3-1 and slr-1 mutant plants were grown on media supplemented with ammonium succinate for one week and subsequently treated with 6 mM KNO₃ or 6 mM KCl for 1–3 hours. The XTH9 gene expression level in the roots was measured via RT-qPCR. (B) Nitrate reductase-null plants (nia1nia2) were grown in media supplemented with ammonium succinate for one week and then treated with 6 mM KNO₃ or 6 mM KCl for 1–3 hours. The RNA level of the XTH9 gene was measured via RT-qPCR. KCl treatment results are shown with white bars, and the KNO₃ treatment results are shown with black bars. *indicates significant differences (p<0.05). The error bars represent SDs (n = 18–24).