Figure 3.

NRT1.13 is expressed in xylem parenchyma cells with higher levels at branch points. (A) and (B) P_NRT1.13:GUS expression pattern in a 24-day-old plant at the vegetative stage (A) or in the branch point of the inflorescence stem in a 44-day-old plant at the reproductive stage (B). The inset is an enlargement of the branch point. (C) RT-qPCR analysis of NRT1.13 expression. Total RNA was isolated from the vegetative and inflorescence tissues of 25- and 33-day-old Col-0 plants, respectively. Values are means ± SE of six independent plants. (RL, rosette leaves; CL_B, basal cauline leaf; B_B, basal branch). (D) to (G) Cross-sectional images below branch points (D, F) and at the branch point (E, G) of P_NRT1.13:NRT1.13-GFP (D, E) and control plants (F, G) grown with 2 mM KNO₃ for 21∼25 days. (H) to (J) Enlarged vascular images from sections of petiole (H), mid-rib of cauline leaf (I), and node (J) from 24-day-old (H) or 59-day-old (I, J) P_NRT1.13:GUS plants. A similar pattern was observed in another independent line. (K) and (L) Enlarged vascular images of nodes from P_NRT1.13:NRT1.13-GFP (K) and control plants (L) grown with 0.2 mM KNO₃ for 54 days. (CL, cauline leaf; B, branch; P, phloem; X, xylem; Vc, vascular tissues connecting to cauline leaf; Vb, vascular tissues connecting to branch).