Figure 3.

Tissue specificity of the HvPht1;1 promoter constructs analyzed by dark-field microscopy (GUS-containing constructs) or confocal microscopy (GFP-containing constructs). At least three independent transgenic lines were examined for each genotype, and typical results are presented. Shown are A and B, Longitudinal sections of P-deficient nodal roots transformed with the promoter::GUS constructs, taken at the site of initial root-hair emergence, stained for GUS activity (bio-refringence of GUS crystals appearing red) for plants containing Pht1;1-Δ2 (A) and Pht1;1-Δ5 (B) promoter::GUS constructs. C to F, Transverse sections of P-deficient nodal roots from plants transformed with full-length HvPht1;1 (C) and truncated Pht1;1-Δ2 (D), Pht1;1-Δ3 (E), and Pht1;1-Δ5 (F) promoter::GFP constructs. The Pht1;1-Δ5 promoter had a similar distribution of activity to Pht1;1-Δ4, and the Pht1;1-Δ2 promoter had a similar distribution of activity to Pht1;1-Δ1 (not shown). Roots were stained with propidium iodide (red fluorescence) to show cell walls. G, Secondary root tip of a plant transformed with the Pht1;1-Δ5 promoter::GFP construct. H, Transverse sections through a secondary root of a plant transformed with the Pht1;1-Δ5 promoter::GFP construct showing the reduced expression in the outer epidermal layer. I and J, Transverse section through leaf blade (I) and leaf midrib (J) for the Pht1;1-Δ5 promoter::GFP construct (chlorophyll autofluorescence shown in red). Leaf cell types showing GFP fluorescence include bulliform cells (BF), vascular bundles (VB), midvein (MV), parenchyma cells (P), and the star-shaped cells of the leaf diaphragm (DM). Scale bars are indicated in μm. Bars = 20 μm (A, B, and H) and 80 μm (C–G and I and J).