The Phenotype Analysis And Map-based Cloning Of Rice Dwarf Mutant

Rice dwarf character is vital in breeding ideal plant type, also as one importantindicator for high production. According to the plant height ratio between dwarf one andwild type in mature period, we can dived the dwarf rice into three categories: semi-dwarfmutant, dwarf mutant and extreme-dwarf mutant. A semi-dwarf mutant refers to matureplant height is less than the wild type one, but higher than half of wild type plant height.Dwarf mutant refers to the mutant plant height is equal to or less than half of the wild typeone. An extreme-dwarf mutant refers to the extreme one. Two materials in this study areextremely dwarf mutants.Plant actin was first proved to be existent by Chinese scientist Yan Longfei. Actin iswidely present in higher plant pollen, leaf epidermal cells, stem phloem, root hairs, sheathcells, tendrils and other tissue cells. It is sometimes associated with the plasma membrane,and sometimes across the cytoplasm, it matters cell division, cell differentiation,intracellular vesicle transportion, cell wall biosynthesis, symbiosis, membrane recycle,exocytosis and endocytosis and so on in different degrees. Plant cell is regulated byactin-binding protein, the length of actin filaments, polarity, stability and three-dimensionalstructures are changing. The actin is connected to cell cytoplasm and other components byactin-binding protein, thereby adjusting the physical and chemical state of the actin.Between the various cell functions after the regulation of cell life processes and proteinswhich regulate many kinds of life processes, actin plays an irreplaceable link. TheLOC_Os02g56540gene in this study is an important one for regulation of actin.285Amutant lead to a extreme dwarf phenotype because of the mutations of LOC_Os02g56540.Forecast is that extremely dwarf phenotype is caused by abnormal cell divison.PartⅠ: We have isolated one dwarf mutant from Nipponbare by EMS mutagenesis,designated as S2-47. The plant height of this mutant is severely dwarfed with dark greenleaf. GA3treatment of seedling and α-amylase activity analysis in endosperm showed thatthe mutated gene is involved in GA biosynthesis. Fine mapping shows that the mutant phenotype is tightly linked with the OsCPS1locus. Sequence analysis showed that there isa single nucleotide deletion in the6th exon in S2-47.PartⅡ: We got a dwarf mutant285A by mutation of japonica varieties Nipponbarethrough UV irradiation. It’s phenotype is extremely dwarf height and dark green leaves.We constructed F2populations through the hybridization between285A and Dular, Finemapping showed the phenotype of285A and LOC_Os02g56540gene are closely linked.Sequence analysis revealed there is gene mutation in LOC_Os02g56540gene of285Amutant: the single-base deletion of the coding region of the gene caused frameshiftmutation.