Figure 3.

Spatial expression patterns of miR399f and AtMYB2. Seeds of PromiR399f:GUS and ProAtMYB2:GUS transgenic lines, which express the GUS reporter from the miR399f and AtMYB2 promoters, respectively, were grown as described in Figure 5. Tissues were stained 7 d after transfer to high-Pi, low-Pi, or Pi-deficient medium. Blue color indicates GUS activity. A to L, Tissues of PromiR399f:GUS transgenic plants. M to X, Tissues of ProAtMYB2:GUS transgenic plants. Arrows indicate lateral roots. Bars = 0.5 mm.