Figure 6.

The ectodomain of BAK1 has a dominant negative effect on MAMP responses and is sufficient to interact with FLS2 in an flg22-dependent manner. A, Quantification of luciferase activity in bak1-4 protoplasts cotransformed with the pFRK1-Luc and indicated constructs treated with buffer as a control, 100 nm flg22, or 100 nm elf18. The BAK1 plasmid was used at a low concentration to avoid constitutive activity. Results shown represent three independent experiments. B, Ethylene production by N. benthamiana leaves transformed with ECD-TM, TM-KD, or empty vector (EV) at various optical densities (as indicated on the x axis) after treatment with flg22 (1 μm), chitin (1 mg mL⁻¹), or buffer (control). The graph shows one representative experiment out of two (n = 6 replicates). Bars and error bars represent means and sd. Significant differences from the control (A) and from the results with EV (B) are marked by asterisks: *, P < 0.05; **, and P < 0.01 (ANOVA test). C, Subcellular localization of ECD-TM in Arabidopsis epidermal cells. Standard confocal micrographs show optical sections of cells after plasmolysis. Bars = 20 mm. D, Coimmunoprecipitation (IP) of FLS2-myc and ECD-TM, or GFP as a control, isolated from N. benthamiana leaves was tested after 15 min of mock or flg22 treatment. Top, Western blot with anti-Myc antibodies; bottom, reanalysis of the blot with anti-GFP antibodies. One-tenth of the total amount of proteins used for coimmunoprecipitation was analyzed and shown as input. Results are representative of three independent experiments.