RESUMO
BACKGROUND: Proper organ development is pivotal for normal rice growth and production. Many genes are involved in this process, and these genes provide a basis for rice breeding. OBJECTIVE: To identify a novel mutation causing developmental defects in rice. METHODS: The phenotype of a rice mutant, stunted sterile (ss), identified from the japonica rice cultivar Samkwang treated with N-methyl-N-nitrosourea, was characterized, including anatomical and pollen activity analyses. A genetic analysis and fine mapping were performed to identify a candidate locus, followed by a sequence analysis to determine the causal mutation for the phenotype. RESULTS: Compared with wild-type plants, the mutant exhibited a 34% reduction in height, 46% reduction in flag leaf width, and complete panicle sterility. Cell proliferation in the leaf and pollen viability were significantly inhibited in the mutant. The mutant phenotypes were controlled by a single recessive gene that was fine-mapped to an 84 kb region between two SNP markers on the short arm of chromosome 5. A candidate gene analysis determined that the mutant carries an 11 bp insertion in the coding region of LOC_Os05g03550, which encodes a protein containing two SANT domains, resulting in a premature termination codon before the conserved domain. CONCLUSIONS: We identified a novel rice gene, Stunted sterile, involved in the regulation of various developmental processes. Our findings improve our understanding of the role of chromatin remodeling in organ development and have implications for breeding owing to the broad effects of the gene on plant growth.
Assuntos
Genes de Plantas , Oryza/crescimento & desenvolvimento , Oryza/genética , Proliferação de Células , Flores/genética , Flores/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Metilnitrosoureia , Mutação , Fenótipo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Caules de Planta/genética , Caules de Planta/crescimento & desenvolvimento , Pólen/genética , Pólen/crescimento & desenvolvimento , República da Coreia , Sequenciamento Completo do Genoma/métodosRESUMO
A generally applicable protocol for organizing comparisons among nuclear medicine clinics created within the IAEA project CRP E2.10.05 was tested in Brazil, Cuba, Czech Republic, India, Iran, Republic of Korea, Romania and Turkey in 2007. Comparisons of measurement of (131)I were organized by local pilot laboratories with different backgrounds and levels of experience in this field. The results and experiences gained were compared and analyzed. A majority of results in each national comparison were within 10% of the reference value.