著者

Reika Hasegawa Kenjiro Fujita Yuichiro Tanaka Hironori Takasaki Miho Ikeda Ayumi Yamagami Nobutaka Mitsuda Takeshi Nakano Masaru Ohme-Takagi

出版者

Japanese Society for Plant Biotechnology

雑誌

Plant Biotechnology (ISSN:13424580)

巻号頁・発行日

vol.39, no.2, pp.185-189, 2022-06-25 (Released:2022-06-25)

参考文献数

27

被引用文献数

2

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The brassinosteroid (BR) phytohormone is an important regulator of plant growth. To identify novel transcription factors that regulate BR responses, we screened chimeric repressor gene silencing technology (CRES-T) plants, in which transcription factors were converted into chimeric repressors by the fusion of SRDX plant-specific repression domain, with brassinazole (Brz), an inhibitor of BR biosynthesis. We identified that a line that expressed the chimeric repressor for zinc finger homeobox transcription factor, BRASSINOSTEORID-RELATED-HOMEOBOX-2 (BHB2-sx), exhibited Brz-hypersensitive phenotype with shorter hypocotyl under dark, dwarf and round and dark green leaves similar to BR-deficient phenotype. Similar to BHB2-sx plants, bhb2 knockout mutant also exhibited Brz hypersensitive phenotype. In contrast, ectopic expression of BHB2 (BHB2-ox) showed hypocotyl elongation phenotype (BR excessive), showing decrease to Brz sensitivity. The expression of the DWF4 and CPD BR biosynthesis genes was repressed in BHB2-sx plants, whereas it was enhanced in BHB2-ox plants. The BR deficient-like phenotype of BHB2-sx plants was partially restored by treatment with brassinolide (BL), indicating that the BR deficient phenotype of BHB2-sx plant may be due to suppression of BR biosynthesis. Our results indicate that BHB2 is a positive regulator of BR response may be due to the promotion of BR biosynthesis genes.