The brassinosteroid signal transduction pathway

Wang, Zhiyong; Wang, Qiaomei; Chong, Kang; Wang, Fengru; Wang, Lei; Bai, Ming-Yi; Chen, Jia

doi:10.1038/sj.cr.7310054

Cited by 75 publications

(47 citation statements)

References 58 publications

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“…BR is a family of polyhydroxylated steroid hormones involved in many aspects of plant growth and development (Belkhadir and Chory, 2006;Wang et al, 2006;Gendron et al, 2008;Tang et al, 2008). The growth of mutants defective in BR biosynthesis and signaling is severely retarded (Azpiroz et al, 1998;He et al, 2005;Belkhadir and Chory, 2006).…”

Section: Discussionmentioning

confidence: 99%

A Leaky Mutation in DWARF4 Reveals an Antagonistic Role of Brassinosteroid in the Inhibition of Root Growth by Jasmonate in Arabidopsis

Ren¹,

Han²,

Wen³

et al. 2009

Plant Physiol.

102

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The F-box protein CORONATINE INSENSITIVE1 (COI1) plays a central role in jasmonate (JA) signaling and is required for all JA responses in Arabidopsis (Arabidopsis thaliana). To dissect JA signal transduction, we isolated the partially suppressing coi1 (psc1) mutant, which partially suppressed coi1 insensitivity to JA inhibition of root growth. The psc1 mutant partially restored JA sensitivity in coi1-2 background and displayed JA hypersensitivity in wild-type COI1 background. Genetic mapping, sequence analysis, and complementation tests revealed that psc1 is a leaky mutation of DWARF4 (DWF4) that encodes a key enzyme in brassinosteroid (BR) biosynthesis. Physiological analysis showed that an application of exogenous BR eliminated the partial restoration of JA sensitivity by psc1 in coi1-2 background and the JA hypersensitivity of psc1 in wild-type COI1 background. Exogenous BR also attenuated JA inhibition of root growth in the wild type. In addition, the expression of DWF4 was inhibited by JA, and this inhibition was dependent on COI1. These results indicate that (1) BR is involved in JA signaling and negatively regulates JA inhibition of root growth, and (2) the DWF4 is down-regulated by JA and is located downstream of COI1 in the JA-signaling pathway.

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Section: Discussionmentioning

confidence: 99%

A Leaky Mutation in DWARF4 Reveals an Antagonistic Role of Brassinosteroid in the Inhibition of Root Growth by Jasmonate in Arabidopsis

Ren¹,

Han²,

Wen³

et al. 2009

Plant Physiol.

102

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“…3E) strongly suggest that OsBZR1 has a DNA binding specificity similar to BZR1 and BZR2/BES1. Although BZR1 and BZR2/BES1 were shown to bind different DNA sequences, these studies used different promoter sequences (15,16), and there is evidence that both BZR1 and BZR2/BES1 mediate feedback inhibition of BR-biosynthetic genes and bind to the SAUR-Ac1 promoter in vivo (7). The PEST domain is known to mediate proteolysis of many proteins in yeast and animals (34)(35)(36).…”

Section: Conserved Structure and Function Of Bzr1 And Osbzr1 Inmentioning

confidence: 99%

“…Molecular genetic studies in A. thaliana have illustrated a BRsignaling pathway that includes two receptor kinases (BRI1 and BAK1) on the cell surface, a soluble glycogen synthase kinase 3-like kinase (BIN2), a phosphatase (BSU1), and two homologous transcription factors (BZR1 and BZR2/BES1) (1,7). BR directly bind to the extracellular domain of BRI1 and activate its intracellular kinase activity (8).…”

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confidence: 99%

Functions of OsBZR1 and 14-3-3 proteins in brassinosteroid signaling in rice

Bai

Zhang²,

Gampala³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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386

336

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Brassinosteroids (BR) are essential growth hormones found throughout the plant kingdom. BR bind to the receptor kinase BRI1 on the cell surface to activate a signal transduction pathway that regulates nuclear gene expression and plant growth. To understand the downstream BR signaling mechanism in rice, we studied the function of OsBZR1 using reverse genetic approaches and identified OsBZR1-interacting proteins. Suppressing OsBZR1 expression by RNAi resulted in dwarfism, erect leaves, reduced BR sensitivity, and altered BR-responsive gene expression in transgenic rice plants, demonstrating an essential role of OsBZR1 in BR responses in rice. Moreover, a yeast two-hybrid screen identified 14-3-3 proteins as OsBZR1-interacting proteins. Mutation of a putative 14-3-3-binding site of OsBZR1 abolished its interaction with the 14-3-3 proteins in yeast and in vivo. Such mutant OsBZR1 proteins suppressed the phenotypes of the Arabidopsis bri1-5 mutant and showed an increased nuclear distribution compared with the wild-type protein, suggesting that 14-3-3 proteins directly inhibit OsBZR1 function at least in part by reducing its nuclear localization. These results demonstrate a conserved function of OsBZR1 and an important role of 14-3-3 proteins in brassinosteroid signal transduction in rice.steroid ͉ nuclear localization ͉ GSK3 ͉ phosphorylation B rassinosteroids (BR) are polyhydroxylated steroid phytohormones with important roles in regulating a wide range of cellular and development processes, such as stem elongation, senescence, seed germination, reproductive development, and photomorphogenesis (1, 2). BR-deficient and BR-insensitive mutants have been identified in Arabidopsis thaliana (1), pea, tomato, barley, and rice (3). Although strong BR mutants show multiple growth defects, including dwarfism, male sterility, delayed senescence, and constitutive photomorphogenesis in the dark (1), weak BR mutants in rice and barley have increased grain yield because of erect leaves and reduced plant height (4-6). It is believed that manipulating BR level or sensitivity can improve plant productivity.Molecular genetic studies in A. thaliana have illustrated a BRsignaling pathway that includes two receptor kinases (BRI1 and BAK1) on the cell surface, a soluble glycogen synthase kinase 3-like kinase (BIN2), a phosphatase (BSU1), and two homologous transcription factors (BZR1 and BZR2/BES1) (1, 7). BR directly bind to the extracellular domain of BRI1 and activate its intracellular kinase activity (8). Activation of BRI1 leads to interaction with, and activation of, another receptor kinase, BAK1, which has been proposed to act as BRI1's coreceptor (9, 10). Downstream of the receptor kinases, the BIN2 kinase and BSU1 phosphatase regulate the phosphorylation status of BZR1 and BZR2/BES1 (11-14). BR activate BZR1 and BZR2/BES1 by inducing their dephosphorylation, possibly by inhibiting BIN2 or activating BSU1. Activated BZR1 and BES1 bind to promoters of BR target genes to regulate their expression (15, 16).BZR1 and BZR2/BES1 share 88...

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“…Extensive molecular genetic and biochemical studies in Arabidopsis thaliana have illustrated a BR signal transduction pathway from the BRI1 receptor kinase at the cell surface to the BZR transcription factors, which regulate BR-responsive gene expression (Vert et al, 2005;Wang et al, 2006b). In the absence of BR, the BZR transcription factors BZR1 and BZR2 (also named BES1) are phosphorylated by the GSK3-like kinase BIN2 Li and Nam, 2002;Yin et al, 2002) and consequently inactivated due to retention in the cytoplasm through interaction with 14-3-3, degradation by the proteasome, and loss of DNA binding activity Vert and Chory, 2006;Gampala et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Antagonistic HLH/bHLH Transcription Factors Mediate Brassinosteroid Regulation of Cell Elongation and Plant Development in Rice andArabidopsis

et al. 2009

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In rice (Oryza sativa), brassinosteroids (BRs) induce cell elongation at the adaxial side of the lamina joint to promote leaf bending. We identified a rice mutant (ili1-D) showing an increased lamina inclination phenotype similar to that caused by BR treatment. The ili1-D mutant overexpresses an HLH protein homologous to Arabidopsis thaliana Paclobutrazol Resistance1 (PRE1) and the human Inhibitor of DNA binding proteins. Overexpression and RNA interference suppression of ILI1 increase and reduce, respectively, rice laminar inclination, confirming a positive role of ILI1 in leaf bending. ILI1 and PRE1 interact with basic helix-loop-helix (bHLH) protein IBH1 (ILI1 binding bHLH), whose overexpression causes erect leaf in rice and dwarfism in Arabidopsis. Overexpression of ILI1 or PRE1 increases cell elongation and suppresses dwarf phenotypes caused by overexpression of IBH1 in Arabidopsis. Thus, ILI1 and PRE1 may inactivate inhibitory bHLH transcription factors through heterodimerization. BR increases the RNA levels of ILI1 and PRE1 but represses IBH1 through the transcription factor BZR1. The spatial and temporal expression patterns support roles of ILI1 in laminar joint bending and PRE1/At IBH1 in the transition from growth of young organs to growth arrest. These results demonstrate a conserved mechanism of BR regulation of plant development through a pair of antagonizing HLH/bHLH transcription factors that act downstream of BZR1 in Arabidopsis and rice.

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The brassinosteroid signal transduction pathway

Cited by 75 publications

References 58 publications

A Leaky Mutation in DWARF4 Reveals an Antagonistic Role of Brassinosteroid in the Inhibition of Root Growth by Jasmonate in Arabidopsis

A Leaky Mutation in DWARF4 Reveals an Antagonistic Role of Brassinosteroid in the Inhibition of Root Growth by Jasmonate in Arabidopsis

Functions of OsBZR1 and 14-3-3 proteins in brassinosteroid signaling in rice

Antagonistic HLH/bHLH Transcription Factors Mediate Brassinosteroid Regulation of Cell Elongation and Plant Development in Rice andArabidopsis

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