Transgenic AtBBX21 potato lines are more robust and shorter than nontransformed plants. A, Representative photograph of 28-d-old nontransformed (Spunta) and transgenic potato plants (CH1, CH2, and CH13). B, AtBBX21 transcript levels of the three independent transgenic lines used in this study (n = 10). C, Plant height and stem diameter in 21-d-old plants (n = 10). D, Fresh weight relative to dry weight in 35-d-old plants (n = 10). n = number of biological replicates. Mean values are shown with error bars indicating se. Asterisks indicate significant difference between nontransformed and transgenic lines (*P < 0.05, **P < 0.01, and ***P < 0.001).