Abstract
Although auxin is known to regulate many processes in plant development and has been studied for over a century, the mechanisms whereby plants produce it have remained elusive. Here we report the characterization of a dominant Arabidopsis mutant, yucca, which contains elevated levels of free auxin. YUCCA encodes a flavin monooxygenase-like enzyme and belongs to a family that includes at least nine other homologous Arabidopsis genes, a subset of which appears to have redundant functions. Results from tryptophan analog feeding experiments and biochemical assays indicate that YUCCA catalyzes hydroxylation of the amino group of tryptamine, a rate-limiting step in tryptophan-dependent auxin biosynthesis.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Alleles
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Amino Acid Sequence
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Arabidopsis / anatomy & histology
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Arabidopsis / genetics*
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Arabidopsis / growth & development
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Arabidopsis / metabolism*
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Arabidopsis Proteins*
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Catalysis
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Cloning, Molecular
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Genes, Plant
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Indoleacetic Acids / biosynthesis*
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Indoleacetic Acids / metabolism*
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Molecular Sequence Data
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Mutation
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Nicotiana / metabolism
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Oxidation-Reduction
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Oxygenases / chemistry
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Oxygenases / metabolism*
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Phenotype
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Plant Roots / growth & development
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Plants, Toxic
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Tryptamines / metabolism
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Tryptophan / analogs & derivatives*
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Tryptophan / metabolism
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Tryptophan / pharmacology
Substances
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Arabidopsis Proteins
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Indoleacetic Acids
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Tryptamines
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5-methyltryptophan
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tryptamine
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Tryptophan
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Oxygenases
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YUC protein, Arabidopsis