Figure 5.

oBIR3-iSGN3 Chimeras Suggest a Role for SERK Proteins in Casparian Strip Formation.

(A) Schematic overview of a biochemically defined SGN3-CIF-SERK signaling complex. The oBIR3-iSGN3 chimera is shown alongside.

(B) Steady state protein levels are visualized by immunoblot with an anti-GFP antibody (detecting the mCitrine tag present in each chimera). The Ponceau-stained membrane is shown as loading control.

(C) Complementation of the sgn3-3 endodermal barrier defect by the chimeric construct SGN3pro:oBIR3-iSGN3. Visualization of endodermal defects with the apoplastic tracer PI, which can reach the stele in barrier-defective plants but is blocked at the endodermis of plants with functional barriers. Pictures were taken around the 50th endodermal cell from the onset of elongation. Bar = 20 µm.

(D) Quantification of the PI block, measured as the number of endodermal cells after the onset of elongation where the PI block is observed. Data are presented as box plots with dot plots overlaid (n ≥ 7). For multiple comparisons between genotypes, Kruskal-Wallis test was performed and nonparametric Tukey’s test was subsequently used as a multiple comparison procedure. Different letters indicate significant difference (P < 0.05).