title: Brd1 gene in maize encodes a brassinosteroid C-6 oxidase.
abstract: The role of brassinosteroids in plant growth and development has been well-characterized in a number of plant species. However, very little is known about the role of brassinosteroids in maize. Map-based cloning of a severe dwarf mutant in maize revealed a nonsense mutation in an ortholog of a brassinosteroid C-6 oxidase, termed brd1, the gene encoding the enzyme that catalyzes the final steps of brassinosteroid synthesis. Homozygous brd1-m1 maize plants have essentially no internode elongation and exhibit no etiolation response when germinated in the dark. These phenotypes could be rescued by exogenous application of brassinolide, confirming the molecular defect in the maize brd1-m1 mutant. The brd1-m1 mutant plants also display alterations in leaf and floral morphology. The meristem is not altered in size but there is evidence for differences in the cellular structure of several tissues. The isolation of a maize mutant defective in brassinosteroid synthesis will provide opportunities for the analysis of the role of brassinosteroids in this important crop system.
authors.affiliation: Department of Biology, Hamline University, Saint Paul, Minnesota, United States of America. imakarevitch01@hamline.edu
authors.forename: Irina
authors.initials: I
authors.lastname: Makarevitch
authors.forename: Addie
authors.initials: A
authors.lastname: Thompson
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Muehlbauer
authors.forename: Nathan M
authors.initials: NM
authors.lastname: Springer
mesh_terms: D000595:Amino Acid Sequence; D060406:Brassinosteroids / Q000378:metabolism* / Q000494:pharmacology; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D017343:Genes, Plant; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000628:therapy; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D060406:Brassinosteroids; D050505:Mutant Proteins; D003577:Cytochrome P-450 Enzyme System