Expression pattern of BU1 analyzed by real-time PCR. Total RNA used in these experiments were isolated from shoots of 2-week-old seedlings after a variety of chemical treatments for 24 h. Data are the average of three or four independent experiments and normalized by 18S rRNA. The error bars indicate sd. A, Response of BU1 to various plant hormones. IAA 10 μm, ABA 100 μm, GA 10 μm, BL 1 μm. B, Effect of CHX on BU1 induction. Wild-type (Nipponbare) plants were treated with mock, CHX, BL, and both CHX and BL. Two-week-old seedlings were pretreated with or without 100 μm CHX for 3 h, before 1 μm BL or mock treatment for 24 h. C and D, Expression of BU1 in response to BL treatment in either d61-2 and d1 or the wild type (T65). Plants were treated with 1 μm BL for 24 h.