Abstract
A carotenoid-derived hormonal signal that inhibits shoot branching in plants has long escaped identification. Strigolactones are compounds thought to be derived from carotenoids and are known to trigger the germination of parasitic plant seeds and stimulate symbiotic fungi. Here we present evidence that carotenoid cleavage dioxygenase 8 shoot branching mutants of pea are strigolactone deficient and that strigolactone application restores the wild-type branching phenotype to ccd8 mutants. Moreover, we show that other branching mutants previously characterized as lacking a response to the branching inhibition signal also lack strigolactone response, and are not deficient in strigolactones. These responses are conserved in Arabidopsis. In agreement with the expected properties of the hormonal signal, exogenous strigolactone can be transported in shoots and act at low concentrations. We suggest that endogenous strigolactones or related compounds inhibit shoot branching in plants. Furthermore, ccd8 mutants demonstrate the diverse effects of strigolactones in shoot branching, mycorrhizal symbiosis and parasitic weed interaction.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Arabidopsis / drug effects
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Arabidopsis / genetics
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Arabidopsis / growth & development
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism
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Dioxygenases
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Genes, Plant / genetics
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Lactones / analysis
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Lactones / chemistry
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Lactones / metabolism*
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Lactones / pharmacology
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Mutation
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Mycorrhizae / physiology
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Oxygenases / genetics
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Oxygenases / metabolism
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Phenotype
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Pisum sativum / drug effects
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Pisum sativum / growth & development
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Pisum sativum / metabolism*
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Pisum sativum / parasitology
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Plant Growth Regulators / analysis
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Plant Growth Regulators / chemistry
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Plant Growth Regulators / metabolism*
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Plant Growth Regulators / pharmacology
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Plant Proteins / genetics
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Plant Proteins / metabolism
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Plant Roots / drug effects
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Plant Roots / metabolism
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Plant Shoots / drug effects
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Plant Shoots / growth & development*
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Plant Shoots / metabolism*
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Plant Shoots / parasitology
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Symbiosis
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Terpenes / analysis
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Terpenes / chemistry
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Terpenes / metabolism
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Terpenes / pharmacology
Substances
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Arabidopsis Proteins
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GR24 compound
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Lactones
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Plant Growth Regulators
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Plant Proteins
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Terpenes
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Oxygenases
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CCD8 protein, Arabidopsis
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Dioxygenases