Phenotypic analysis of nis1, nis2, ncr1-1. A. Comparison of NIR-LUC activity in nis1, nis2 and ncr1-1. LUC activities were measured after 2 h incubation with either 10 mM KCl or KNO3. The NIR-LUC transgenic line in Col is used as the wild type control. Three seedlings were pooled and grinded for protein concentration determination and LUC activity analysis. Values shown are means ± s.d. of three or four biological replicates. B. Relative endogenous NIR expression in nis1, nis2 and ncr as measured by real-time PCR. Plants were treated with either 10 mM KNO3 or KCl for 2 h. Relative expression of NIR is normalized to the expression of TUB4. The relative expression level is calculated relative to the value of wild type treated with KCl. Values shown are means ± s.d. of three biological replicates. C. Altered root architecture in nis1. Plants were grown on medium containing 2.5 mM ammonium succinate for 3 days and transferred to medium containing 5 mM KNO3 for 8 days. D. nis2 showing small pale-green leaves after plants grown in soil for 33 days. E. The lateral root de-suppression phenotype in ncr1-1. Seedlings were grown on medium containing 50 mM KNO3 as the sole nitrogen source for 14 days. Scale bar = 1 cm.