RRC ID 657
Author Hong Z, Ueguchi-Tanaka M, Shimizu-Sato S, Inukai Y, Fujioka S, Shimada Y, Takatsuto S, Agetsuma M, Yoshida S, Watanabe Y, Uozu S, Kitano H, Ashikari M, Matsuoka M.
Title Loss-of-function of a rice brassinosteroid biosynthetic enzyme, C-6 oxidase, prevents the organized arrangement and polar elongation of cells in the leaves and stem.
Journal Plant J.
Abstract Molecular genetic and physiological studies on brassinosteroid (BR)-related mutants of dicot plants have revealed that BRs play important roles in normal plant growth and development. However, little is known about the function of BR in monocots (grasses), except for the phenotypic analysis of a rice mutant partially insensitive to BR signaling. To investigate the function of BR in monocots, we identified and characterized BR-deficient mutants of rice, BR-deficient dwarf1 (brd1). The brd1 mutants showed a range of abnormalities in organ development and growth, the most striking of which were defects in the elongation of the stem and leaves. Light microscopic observations revealed that this abnormality was primarily owing to a failure in the organization and polar elongation of the leaf and stem cells. The accumulation profile of BR compounds in the brd1 mutants suggested that these plants may be deficient in the activity of BR C-6 oxidase. Therefore, we cloned a rice gene, OsDWARF, which has a high sequence similarity to the tomato C-6 oxidase gene, DWARF. Introduction of the wild-type OsDWARF gene into brd1 rescued the abnormal phenotype of the mutants. The OsDWARF gene was expressed at a low level in all of the examined tissues, with preferential expression in the leaf sheath, and the expression was negatively regulated by brassinolide treatment. On the basis of these findings, we discuss the biological function of BRs in rice plants.
Volume 32(4)
Pages 495-508
Published 2002-11
PII 1438
PMID 12445121
MeSH Alleles Amino Acid Sequence Brassinosteroids Cell Polarity Cholestanols / pharmacology Gene Expression Profiling Genes, Plant / genetics Genetic Complementation Test Molecular Sequence Data Mutation* Oryza / cytology* Oryza / enzymology* Oryza / genetics Oryza / growth & development Oxidoreductases / chemistry Oxidoreductases / genetics* Oxidoreductases / metabolism* Phenotype Plant Leaves / cytology* Plant Leaves / enzymology Plant Leaves / genetics Plant Leaves / growth & development Plant Stems / cytology* Plant Stems / enzymology Plant Stems / genetics Plant Stems / growth & development Steroids, Heterocyclic / pharmacology
IF 5.775
Times Cited 159
Rice d18? Induced Mutation Lines