Overexpression of both wild-type (WT) and kinase mutant of MEKK2 induces cell death. A, Overexpression of MEKK2 induces dwarf phenotype. Four-week-old soil-grown plants were photographed. Transgenic plants of 35S::MEKK2-HA in wild type show severe dwarfism, and were grouped into three categories. Each category was calculated as a percentage of the total dwarf plants. Bottom shows the protein expression of MEKK2-HA from the above plants detected by immunoblot (IB) with an α-HA antibody. Coomassie Brilliant Blue (CBB) staining was used as the loading control. Bars = 1 cm. B, Overexpression of MEKK2KM, a kinase-dead mutant (Lys-529 to Met), triggers plant dwarfism. Five-week-old soil-grown plants were photographed. Transgenic plants of 35S::MEKK2KM-HA in wild type show severe dwarfism, and were grouped into three categories. Each category was calculated as a percentage of the total dwarf plants. Immunoblots with an α-HA antibody show MEKK2KM-HA protein expression and CBB staining was used as the loading control (bottom). Bars = 1 cm. C, Overexpression of MEKK2KM-FLAG triggers plant dwarfism. Five-week-old soil-grown plants were photographed. Transgenic plants of 35S::MEKK2KM-FLAG in wild type show severe dwarfism, and were grouped into three categories. Each category was calculated as a percentage of the total dwarf plants. Immunoblots with an α-FLAG antibody show MEKK2KM-FLAG protein expression and CBB staining was used as the loading control (right). Plant pictures were digitally extracted and placed on a black background. Bars = 1 cm.