title: Sorghum DW1 positively regulates brassinosteroid signaling by inhibiting the nuclear localization of BRASSINOSTEROID INSENSITIVE 2.
abstract: Semi-dwarf traits have been widely introgressed into cereal crops to improve lodging resistance. In sorghum (Sorghum bicolor L. Moench), four major unlinked dwarfing genes, Dw1-Dw4, have been introduced to reduce plant height, and among them, Dw3 and Dw1 have been cloned. Dw3 encodes a gene involved in auxin transport, whereas, Dw1 was recently isolated and identified as a gene encoding a protein of unknown function. In this study, we show that DW1 is a novel component of brassinosteroid (BR) signaling. Sorghum possessing the mutated allele of Dw1 (dw1), showed similar phenotypes to rice BR-deficient mutants, such as reduced lamina joint bending, attenuated skotomorphogenesis, and insensitivity against feedback regulation of BR-related genes. Furthermore, DW1 interacted with a negative regulator of BR signaling, BRASSINOSTEROID INSENSITIVE 2 (BIN2), and inhibited its nuclear localization, indicating that DW1 positively regulates BR signaling by inhibiting the function of BIN2. In contrast to rice and wheat breeding which used gibberellin (GA) deficiency to reduce plant height, sorghum breeding modified auxin and BR signaling. This difference may result from GA deficiency in rice and wheat does not cause deleterious side effects on plant morphology, whereas in sorghum it leads to abnormal culm bending.
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furou-cho, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Hirano
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furou-cho, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Kawamura
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furou-cho, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Araki-Nakamura
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furou-cho, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Fujimoto
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furou-cho, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Kozue
authors.initials: K
authors.lastname: Ohmae-Shinohara
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furou-cho, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Yamaguchi
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furou-cho, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Fujii
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furou-cho, Nagoya, Aichi, 464-8601, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Education and Research Center of Alpine Field Science, Faculty of Agriculture, Shinshu University, Minamiminowa, Nagano, 399-4598, Japan.
authors.forename: Shigemitsu
authors.initials: S
authors.lastname: Kasuga
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Furou-cho, Nagoya, Aichi, 464-8601, Japan. sazuka@agr.nagoya-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sazuka