Genetic study on the mutants for protein body in rice endosperm to improve the grain quality.

水稻奇异蛋白主要存在于PB- <I>和PB <II>两种蛋白体中，它们在形态和多肽组成上存在差异。本研究对水稻胚乳蛋白体突变体进行筛选、鉴定和遗传分析，为水稻贮藏蛋白质的改良获取遗传资源。结果表明：1)通过对分离的PB- < 1 >的分析，明确了其多肽组成和消化率。2)用MNU处理受精卵细胞，从3000个左右的突变系中筛选出17个蛋白体突变系，用SDS-PAGE从2000多个水稻品种中筛选出46个蛋白体突变系。3)根据多肽相对含量的变化，将其分为四种类型。4)对突变体淀粉胚乳中提取蛋白的测定结果显示，突变体淀粉胚乳中蛋白和谷蛋白含量发生变化，而球蛋白含量未发生变化。5)对4种突变体胚乳分离的蛋白体进行SDS-PAGE分析，确定3种突变体与PB- < 1 >有关。6)对3种突变体的基因分析表明，它们各自受不同的单隐性基因控制。三体分析表明，突变多肽基因rsp-1和rsp-2分别位于第9和第10染色体上。7)通过免疫反应获得蛋白体各多肽定量变化的突变体。

The rice strage proteins deposite in the two types of protein bodies, PB- <I> and PB <II> , which are characterized from each other by differences in the morphology and the polypeptide composition. This study deals with the screening of mutants for protein bodies in rice endosperm, and characterization and genetic analysis of the mutants to obtain genetic resources for qualitative improvement of rice storage protein. The results are given as follows:1) From the results of the analysis of the isolated PB- <I> , its polypeptide composition and digestibility were cleared.2) Seventeen mutant lines for protein body were selected from about 3000 mutant lines induced by the treatment of the fertilized egg cell with MNU and fourty six varieties were obtained from about 2000 rice varieties by SDS-PAGE.3) They have been classified into four types on the basis of variation of the relative content of the polypeptide.4) In determination of extracted protein in the starchy endosperm of the mutants, it was revealed that the content of prolamin and glutelin but not globulin were brought on a change.5) By the SDS-PAGE analysis of protein bodies isolated from the endosperm of four types of mutants, it was clarified that three were concerned with PB- <I> .6) Gene analysis of three types of mutants showed that each of them was controlled by different single recessive genes. The trisomic analysis indicated that two genes for mutated polypeptide, rsp-1 and rsp-2, located on chromosome 9 and 10 respectively.7) The mutants for quantitative changes in each polypeptide of protein body were obtained by immune react.