Figure 2. Root transverse sections and electron micrographs of tomato and Arabidopsis show ^GFP E. coli in the apoplast and inside root cells.

E. coli was detected inside tomato roots (A, C and D, E and F) and Arabidopsis roots (B). (A and B) Fluorescent images of transverse sectioned roots taken by CLSM. (C and D) Images taken by a transmission electron microscope. White triangles in (C) indicate E. coli cell present in apoplast. (D) Roots were probed with immunogold-labeled anti-GFP revealing E. coli in root cortex cells. Sub-image in (D) is a detail of dash-white square box. Gold labeling is marked with white arrows. Rhizodermis cell (R) and plant cell wall (pcw) is indicated. (F) is a detail image of (E) showing plant cells containing E. coli, and both images were taken by SEM.