Fig. 4

SiBRI1 overexpression activated BR signaling in bri1-116 plants. (A), Phenotypes of Col-0 and bri1-116 mutant plants overexpressing SiBRI1 that were grown in the presence of the indicated concentration of BL for 7 days. Scale bar = 1 cm. (B), Relative root lengths of the plants in (A). Error bars indicate the mean ± standard deviation (SD). N > 30. Statistically significant differences are indicated by different lowercase letters (p < 0.05, two-way ANOVA with Tukey’s significant difference test). (C), Phenotypes of Col-0 and bri1-116 mutant plants overexpressing SiBRI1 that were grown in the presence of the indicated concentration of PCZ for 7 days. Scale bar = 1 cm. (D), Relative hypocotyl lengths of the plants in (C). Error bars indicate the mean ± standard deviation (SD). N > 30. Statistically significant differences are indicated by different lowercase letters (p < 0.05, two-way ANOVA with Tukey’s significant difference test). (E), Immunoblot analysis of BZR1 in transgenic plants overexpressing SiBRI1 in the bri1-116 mutant or wild type background under PCZ. pAtBZR1 showed the phosphorylation form of AtBZR1, and AtBZR1 showed the unphosphorylated form of AtBZR1. Expression levels of HSP70 and AtBZR1 in the transgenic plants shown in (C). Ponceau S staining of the Rubisco large subunit and the expression level of HSP70 was used as an equal loading control