title: Brassinosteroid signaling regulates leaf erectness in Oryza sativa via the control of a specific U-type cyclin and cell proliferation.
abstract: Leaf erectness is key in determining plant architecture and yield, particularly in cereal crops. Brassinosteroids (BRs) play a unique role in controlling this trait in monocots, but the underlying cellular and molecular mechanisms remain big mysteries. Here we report that the abaxial sclerenchyma cell number of rice lamina joints (LJs) is closely related to leaf erectness, and BR signaling tightly regulates their proliferation. We identified a rice U-type cyclin CYC U4;1 enriched in rice LJs, with its expression accompanying LJ development. Genetic and biochemical studies demonstrated that CYC U4;1 plays a positive role in promoting leaf erectness by controlling the abaxial sclerenchyma cell proliferation. Furthermore, BR signaling inhibits the abaxial sclerenchyma cell division by coordinately regulating CYC U4;1 expression through BES1 and CYC U4;1 protein activity through GSK3 kinases. These results support a key role of the cyclin CYC U4;1 in mediating BR-regulated cell division to control leaf erectness.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Shiyong
authors.initials: S
authors.lastname: Sun
authors.affiliation: College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China.
authors.forename: Donghong
authors.initials: D
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China.
authors.forename: Shenglong
authors.initials: S
authors.lastname: Qiao
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Chaonan
authors.initials: C
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China.
authors.forename: Chengxiang
authors.initials: C
authors.lastname: Li
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China.
authors.forename: Hongyun
authors.initials: H
authors.lastname: Shen
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: xlwang@mail.hzau.edu.cn.
authors.forename: Xuelu
authors.initials: X
authors.lastname: Wang
mesh_terms: D060406:Brassinosteroids / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D049109:Cell Proliferation / Q000235:genetics*; D016213:Cyclins / Q000096:biosynthesis / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D038362:Glycogen Synthase Kinase 3; D009687:Nuclear Proteins / Q000096:biosynthesis; D012275:Oryza / Q000254:growth & development*; D010766:Phosphorylation; D018515:Plant Leaves / Q000254:growth & development / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics; D011494:Protein Kinases / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D060406:Brassinosteroids; D016213:Cyclins; D009687:Nuclear Proteins; D010940:Plant Proteins; D011494:Protein Kinases; D038362:Glycogen Synthase Kinase 3