Function of B-Box proteins under shade
Plants are capable of perceiving changes in the light environment and finely adjust their growth and development. Reductions of red to far-red ratio (R:FR) generated by an increase of the plant canopy above the plant are sensed by the phytochrome system triggering the shade-avoidance syndrome (SAS)...
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| Autores principales: | , , |
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2011
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15592316_v6_n1_p_Crocco http://hdl.handle.net/20.500.12110/paper_15592316_v6_n1_p_Crocco |
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| Sumario: | Plants are capable of perceiving changes in the light environment and finely adjust their growth and development. Reductions of red to far-red ratio (R:FR) generated by an increase of the plant canopy above the plant are sensed by the phytochrome system triggering the shade-avoidance syndrome (SAS) that includes elongation of vegetative structures, reduction of branching and acceleration of flowering. Albeit the SAS is a strategy of major adaptative significance in plant communities, involving if massive changes in gene expression, our knowledge of the SAS signaling network is still fragmented. By a selection and characterization of a T-DNA mutant with a long hypocotyl under shade, we identified BBX21, a protein with two B-box domains, that is involved in the SAS. BBX21 belongs to a small eight member family of B-box-containing proteins with both opposite and additive functions in the SAS signaling. BBX21 downregulates the gene expression of auxin, brassinosteroid and ethylene signaling pathway components under shade. Furthermore BBX21 is a transcription factor that interacts genetically with COP1. We propose a model in which a dynamic balance of positive and negative B-box transcriptional regulators acts as a gas-and-brake mechanism into the COP1 signaling to regulate the expression of SAS. © 2011 Landes Bioscience. |
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