Figure 1.

Auxin accumulates in Frankia-infected cells in C. glauca nodules. A, Auxin content measured by LC-MS in C. glauca roots of noninoculated plants (control), roots, and nodules harvested 3 weeks after inoculation by Frankia. Significance was tested by an ANOVA test (P < 0.01). FW, Fresh weight. B, Immunolocalization of IAA. The signal is found in cells infected by Frankia. C, Immunolocalization of PAA. A very strong signal is detected in cells infected by Frankia. D, Control immunolocalization. The section was hybridized only with the secondary antibody. No signal is detected in infected cells. Autofluorescence of the cell wall of infected cells can be detected. Scale bars: 100 μm (B and D), 50 μm (C).