Figure 11.

Expression Pattern of BTI Proteins in Plant Tissues and Cells.

(A) Protein gel blot analysis showing that BTI1 protein is expressed in root tissues, rosette leaves, and the bolt regions of the inflorescence of mature Arabidopsis plants, but not in siliques, flowers, or cauline leaves. BTI1 protein is also expressed in Arabidopsis suspension cells.

(B) Confocal fluorescence microscopic images of transgenic Arabidopsis root tips expressing GFP or BTI-GFP fusion proteins. (1) Single optical section of root tip cells from GFP transgenic plants. (2 and 3) Single optical sections of root tip cells from BTI1-GFP transgenic plants. (4) Single optical section of root tip cells from BTI3-GFP transgenic plants. (5) BTI1-GFP protein is not associated with the plant cell wall. BTI1-GFP transgenic plants were treated with 0.8 M mannitol for 30 to 60 min before examining by confocal microscopy. The images indicate that GFP alone localizes through the cytoplasmic region and the nucleus, whereas the BTI-GFP fusion proteins localize throughout the cytoplasm, preferentially to the cell periphery, but not the walls, of root tip cells. Bars (1, 2, 4, and 5) = 25 μm; bar (3) = 5 μm.