Figure 5.

EIN3 Acts as the Immediate Upstream Regulator of NRT1.5.

(A) ChIP assay using anti-GFP antibody followed by qPCR detection of the enrichment of P1 to P8 regions as indicated in the inset, where a schematic diagram of the 3293-bp promoter fragment upstream of the NRT1.5 start codon is shown and the black arrowheads indicate putative EIN3 binding motifs. Chromatin was isolated from root samples of 4-week-old 35S:EIN3-GFP/ein3 eil1 plants exposed to 20 μM ACC + 50 μM MeJA for 6 h. TUB2 and EBF2 were used as internal and positive controls, respectively. Values are means ± sd; n = 3.

(B) and (C) Representative EMSA for EIN3 binding to the fragments of P5 (B) and P7 (C) in the NRT1.5 promoter.

(D) NRT1.5 expression in roots of 4-week-old wild-type and ein3 eil1 plants treated with 20 μM ACC, 50 μM MeJA, 20 μM ACC + 50 μM MeJA (A+J), 200 μM CdCl₂, or 150 mM NaCl for 6 h. The inset shows NRT1.5 expression in 6-d-old wild-type Col-0 and EIN3ox seedlings. Data were normalized to those of SAND. Values are means ± sd; n = 3.