Breeding of low prolamin rice

低醇溶蛋白突变体的筛选从诱变处理的后代中筛选出低醇溶蛋白突变株系。从一些国家采集的约2000份地方稻种中检测到醇溶蛋白多肽的多样性变异。低醇溶蛋白突变体ESP2在小试中表现出较低的酸度和较低的氨基酸含量，但具有很高的溶解度。低醇溶蛋白基因的分离根据低醇溶蛋白突变体的连锁分析结果，将ESP1基因定位在4号染色体上1.4 cM的区域，构建ESP1基因的高密度连锁图谱。利用水稻品种‘Kinmaze’种子发育过程中构建的cDNA文库，克隆了与醇溶蛋白向pBI积累相关的pDI和Bip基因。低醇溶蛋白突变体的细胞化学分析低醇溶蛋白突变体由两类组成，即半胱氨酸残基较差的醇溶蛋白(Cys-P醇溶蛋白)和富含半胱氨酸残基的醇溶蛋白(Cys-R醇溶蛋白)。对低醇溶蛋白突变体esp3和esp4的分析表明，Cys-R和Cys-P醇溶蛋白分别在种子发育的早期和后期积累到PBI中。对每一类醇溶蛋白抗体的分析表明，Cys-P和Cys-R醇溶蛋白分别积聚在PBI的中心和外围。认为Cys-P醇溶蛋白作为核心起重要作用，Cys-R起到填充PBI内壁的作用。

Screening of low prolamin mutantsLow prolamin mutant lines were selected from the progeny of the mutagenesis treatment. The diverse variation for prolamin polypeptides were detected from the native rice varieties, about 2000, collected from some countries. The crossing among low prolamin varieties was done, the progeny is being analyzed.Brewing prosperity of low prolamin mutantThe low prolamin mutant, esp2, showed the low acid degree and low amino acid degree by small scale brewing test, though the mutant showed very high dissolving degree. The results will be helpful on the efficient utilization of the materials.Isolation of the gene for low prolaminBy the results of the linkage analysis of the low prolamin mutant, esp1 gene is positioned within the 1.4 cM region on chromosome 4. The high-density linkage map of esp1 gene will be constructed.The genes of PDI and BiP, related to the accumulation of the prolamin into PBI, were cloned using the cDNA library constructed from the developing seed of rice cultivar 'Kinmaze'. The specific antibodies were prepared based on the cDNA clone.Cytochemical analysis of the low prolamin mutantsProlamin consists of two classes, the cysteine residue poor prolamin (Cys-P prolamin) and the cysteine residue rich prolamin (Cys-R prolamin). The analysis of low prolamin mutants esp3 and Esp4 indicates that Cys-R and Cys-P prolamins are accumulated into PBI at the early and late stages, respectively, during seed development. The analysis by the antibodies to each prolamin classes indicates that Cys-P and Cys-R prolamins accumulate in the center and the periphery of PBI, respectively. It is thought that Cys-P prolamin plays an important role as a core and Cys-R plays the role of filling the inside of PBI.