Figure 6.

The wer-4 mutant disrupts root epidermal cell fate establishment. A, Accumulation of the GL3-YFP fusion protein in wild-type (WT) and wer-4 seedling roots bearing the GL3::GL3-YFP transgene. White stars mark the H-position cell files. The red color represents propidium iodide and the green color represents YFP. For each genotype, the left and right images show the same root focused on the epidermal and stele layers. Bar = 50 μm. B, Accumulation of the CPC-GFP fusion protein in wild-type and wer-4 seedling roots bearing the CPC::CPC-GFP transgene. White stars mark the H-position cell files. The red color represents propidium iodide and the green color represents GFP. For each genotype, the left and right images show the same root focused on the epidermal and stele layers. Bar = 50 μm. C, Quantifications of root epidermis specification in seedling roots of the wild type, scm-2, wer-4, and scm-2 wer-4. Error bars represent sd from three replicates. Statistical significance was determined by two-way ANOVA: *, P < 0.05. D, Quantifications of the CPC-GFP signals in epidermis of wild-type and wer-4 roots. For each root, the GFP signals within all measurable epidermal cells were measured and results are plotted using the average GFP signals per cell. A total of 20 roots were measured for each genotype. Statistical significance was determined with Student’s t test: ***, P < 0.001. E, Histograms of GL3::GL3-YFP signal levels in N- and H-position cells of wild-type and wer-4 seedling root tips (n = 150). Ten cells in each position were analyzed per root, and 15 roots were used for each genotype.