Confocal microscopy images of immunofluorescence staining for <i>Bradyrhizobium</i> sp. prepared from pure culture and plant nodules.

<p>Immunofluorescence staining of various bacterial targets in both pure culture and nodule forms are shown. The bacteria tested include <i>Bradyrhizobium</i> sp. strains DOA9 (<b>A</b>), SUTN9-2 (<b>B</b>), SUTN1-12 (<b>C</b>), and USDA110 (<b>D</b>). The bacterial samples were stained with various antibodies, i.e., rabbit polyclonal antibody, two clones of phage-displayed rabbit scFv, i.e., RB9 and RG8, which contained identical DNA sequence. Phage-displayed scFv antibody clone 3C1 that bind aflatoxin B1 was used as a negative control. Green spots indicated the green fluorescent staining of phage display scFv or polyclonal antibody, using secondary antibody conjugated to FITC. Plant cell walls were stained with a blue fluorophore (Calcofluor white M2R) and emitted blue color. The bacteroid are shown as green spots inside a blue plant cavity. Scale bar is 10 μm at 80× magnification, and 100 μm at 10× magnification for pure culture and nodule samples, respectively.</p>