abi4-102 was hypersensitive to BR and hyposensitive to BRZ. A to D, Phenotype of abi4-102 grown in one-half strength MS in light (A), grown in one-half strength MS in dark (B), grown in one-half strength MS + 1 μm BRZ in light (C), and grown in one-half strength MS + 1 μm BRZ in dark (D). E to H, Phenotype of ABI4-cFLAG grown in one-half strength MS in light (E), grown in one-half strength MS in dark (F), grown in one-half strength MS + 1 μm BRZ in light (G), and grown in one-half strength MS + 1 μm BRZ in dark (H). I, Quantification of root length of Col-0, abi4-102, and ABI4-cFLAG grown in one-half strength MS containing different concentration of BL. Each data point represents the average of 25 seedlings of duplicated experiments, and the error bars denote ± sd. J, Gene expression level of CPD, DWF4, and SAUR-AC1 in treated with or without 1 µm BL of Col-0, abi4-102, and ABI4-cFLAG. For each sample, the RT-qPCR assays were repeated three times, and the error bars denote ± sd.