FIGURE 7.

FIP1 and CPSF30 function in the same nitrate signaling pathway. (A) Nitrate responsiveness in 4-days-old WT, fip1, cpsf30, and fip1cpsf30 seedlings grown in KNO₃ medium, revealed using a fluorescent reporter system (NRP-YFP). (B) Quantification of root fluorescence in the plants described in (A). Error bars represent the SD of the biological replicates (n = 60). (C) The expression of nitrate-responsive genes in the roots of WT, fip1, cpsf30, and fip1cpsf30 plants. The seedlings were grown for 7 days on the medium containing 2.5 mM ammonium succinate as the sole nitrogen source, and then treated with 10 mM KNO₃ or 10 mM KCl as a control for 2 h. The transcripts of the nitrate-responsive genes were quantified using qPCR. Error bars represent the SD of the biological replicates (n = 4). Asterisks and different letters indicate significant differences (p < 0.05, U-test).