A Role for Flavin Monooxygenase-Like Enzymes in Auxin Biosynthesis

• Published in: Science (American Association for the Advancement of Science) Vol. 291; no. 5502; pp. 306 - 309
• Main Authors: Zhao, Yunde, Christensen, Sioux K., Fankhauser, Christian, Cashman, John R., Cohen, Jerry D., Weigel, Detlef, Chory, Joanne
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 12.01.2001; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Alleles; Amino Acid Sequence; Amino acids; Arabidopsis - anatomy & histology; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins; Auxin; Auxins; Biological and medical sciences; Biosynthesis; Catalysis; Cloning, Molecular; Coding; Developmental Stages; Enzymes; Flowers & plants; Fundamental and applied biological sciences. Psychology; Genes, Plant; Genetics; Growth regulators; Hormones; Hypocotyls; Individualized Instruction; Indoleacetic Acids - biosynthesis; Indoleacetic Acids - metabolism; Insulin antibodies; Metabolism; Molecular Sequence Data; Mutation; Nicotiana - metabolism; Oxidation-Reduction; Oxygenases - chemistry; Oxygenases - metabolism; Phenotype; Phenotypes; Plant hormones; Plant physiology and development; Plant Roots - growth & development; Plants; Plants, Toxic; Seedlings; Transgenic animals; Tryptamines - metabolism; Tryptophan - analogs & derivatives; Tryptophan - metabolism; Tryptophan - pharmacology; Yucca; United States; Auxin; Enzyme; Biosynthesis; Gene expression; Oxygenase; Arabidopsis thaliana; Gene; Cruciferae; Dicotyledones; Angiospermae; Plant growth substance; Spermatophyta; Oxidoreductases; Mutation; Experimental plant; Aminoacid sequence
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.291.5502.306

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 tryptophandependent auxin biosynthesis.