稻米蛋白质组分及总蛋白质含量与淀粉RVA谱特征值的关系

 利用低谷蛋白含量（low glutelin content， LGC）粳稻品种W1721与大面积应用的杂交粳稻恢复系轮回422构建了重组自交系群体。根据种子总蛋白质的SDS PAGE带型，推断各单株LGC位点的基因型。在排除脂肪的影响下，比较了基因型LGCLGC（谷蛋白含量较醇溶蛋白低）与基因型lgclgc（谷蛋白含量较醇溶蛋白高）在RVA谱特征值上的差异，以及同一基因型内总蛋白质含量与淀粉RVA谱特征值的关系。结果表明基因型LGCLGC的崩解值和回复值的平均值分别显著和极显著大于基因型lgclgc；LGC对崩解值和回复值的相对加性效应分别为3.91%和4.45%，贡献率分别为4.81%和12.81%。LGCLGC型的稻米，总蛋白质含量与崩解值和消减值分别存在显著的负线性回归和正线性回归关系，贡献率分别为9.86%和11.48%；lgclgc型的稻米，总蛋白质含量与消减值和回复值都存在极显著的负线性回归关系，贡献率分别为1341%和27.88%。结合前人研究认为，稻米食味品质受谷蛋白相对于醇溶蛋白的含量以及总蛋白质含量的影响；而总蛋白质含量对食味品质的影响因谷蛋白相对于醇溶蛋白的含量的不同而异。因此，育种工作中应当把谷蛋白相对于醇溶蛋白的含量以及总蛋白质含量同时作为选择指标。

Relationship Between Protein Composition and Total Protein Content and Starch RVA Profile Properties in Rice

A recombinant inbred line (RIL) population derived from the cross between two japonica rice, W1721 with low glutelin content (LGC) and Lunhui 422 with normal glutelin content, was developed to investigate the effect of LGC gene on RVA profile properties and relationship between total protein content and starch RVA profile properties. According to SDS PAGE band type, genotypes of individuals at LGC locus were estimated: LGCLGC with low glutelin content and high prolamin content, lgclgc with high glutelin content and low prolamin content in the RIL population. The RVA profile characteristics of defatted rice showed breakdown and consistence values of LGCLGC were extremely significantly higher than those of lgclgc. The LGC gene exhibited a highly significant relative additive effect on consistence value (4.45%), explaining 12.81% of the phenotypic variance, whereas the LGC exhibited a significant relative additive effect on breakdown value (3.91%), explaining 481% of the phenotypic variance. For the genotype LGCLGC, total protein content had a negative and positive linear regression relationship with breakdown value (P<0.045) and setback value (P<0.030), explaining 9.86% and 11.48% of the phenotypic variance, respectively, whereas for the genotype lgclgc, total protein content had a negative linear regression relationship with setback value (P<0.006) and consistence value (P<0.000), explaining 13.41% and 27.88% of the phenotypic variance, respectively. Combined with previous studies, it is deduced that eating quality of rice is determined, at least in part, by both the relative proportions of the two major protein fractions, glutelin and prolamin, and total protein content. Effect of total protein content on eating quality of rice varied with the relative proportions of glutelin and prolamin. Therefore, it may be possible to develop rice with desired levels of eating quality by breeding varieties with particular proportions of glutelin and prolamin and appropriate total protein content.