Overexpression of WIND homologs promotes cell dedifferentiation without exogenous phytohormones. (A–C) 14-d-old wild-type (WT, A) and 14, 21-d-old (B, C, respectively) 35S:WIND4 seedlings grown on phytohormone-free MS medium. 35S:WIND4 seedlings display severe morphological defects and callus induction. (D) 60-d-old callus excised from 35S:WIND4 seedlings. (E, F) 8-d-old XVE-WIND1 seedlings germinated on phytohormone-free MS medium without (-) (E) or with (+) 10 mM 17b-estradiol (F). (G, H) Cross sections of cotyledon epidermal cells in 9-d-old XVE-WIND1 plants. XVE-WIND1 seedlings were germinated without (G) or with (H) 10 mM 17b-estradiol. Cellular boundaries are visualized by propidium iodide (PI) and cross sections are generated from confocal Z-stacks. Scale bars, 2 mm (A, C, D), 500 mm (B, E, F), 20 mm (G, H).