Abstract
Rice MONOCULM 1 (MOC1) and its orthologues LS/LAS (lateral suppressor in tomato and Arabidopsis) are key promoting factors of shoot branching and tillering in higher plants. However, the molecular mechanisms regulating MOC1/LS/LAS have remained elusive. Here we show that the rice tiller enhancer (te) mutant displays a drastically increased tiller number. We demonstrate that TE encodes a rice homologue of Cdh1, and that TE acts as an activator of the anaphase promoting complex/cyclosome (APC/C) complex. We show that TE coexpresses with MOC1 in the axil of leaves, where the APC/C(TE) complex mediates the degradation of MOC1 by the ubiquitin-26S proteasome pathway, and consequently downregulates the expression of the meristem identity gene Oryza sativa homeobox 1, thus repressing axillary meristem initiation and formation. We conclude that besides having a conserved role in regulating cell cycle, APC/C(TE) has a unique function in regulating the plant-specific postembryonic shoot branching and tillering, which are major determinants of plant architecture and grain yield.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Anaphase-Promoting Complex-Cyclosome
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Arabidopsis / genetics
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Arabidopsis / metabolism
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Cell Cycle Checkpoints / genetics
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Cell Cycle Proteins / genetics*
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Cell Cycle Proteins / metabolism*
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Cell Division / genetics
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Gene Expression Regulation, Plant
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Homeodomain Proteins / biosynthesis
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Homeodomain Proteins / genetics
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Meristem / genetics
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Meristem / growth & development
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Meristem / metabolism
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Mutation
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Oryza / genetics*
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Oryza / growth & development
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Oryza / metabolism*
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Plant Proteins / biosynthesis
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Plant Proteins / genetics*
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Plant Proteins / metabolism*
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Plant Shoots / genetics
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Plant Shoots / metabolism
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Proteasome Endopeptidase Complex / metabolism
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Schizosaccharomyces / genetics
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Schizosaccharomyces / metabolism
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Trans-Activators / biosynthesis
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Trans-Activators / genetics
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Ubiquitin-Protein Ligase Complexes / metabolism*
Substances
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Cell Cycle Proteins
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Homeodomain Proteins
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OSH1 protein, Oryza sativa
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Plant Proteins
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Trans-Activators
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Ubiquitin-Protein Ligase Complexes
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Anaphase-Promoting Complex-Cyclosome
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Proteasome Endopeptidase Complex
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ATP dependent 26S protease