稻米糊化温度的遗传与分子机理研究进展

糊化温度(gelatinization temperature, GT)是衡量稻米蒸煮品质和口感的重要参数之一。低GT稻米比高GT稻米蒸煮时需要较少的能量投入。支链淀粉的结构,特别是其分支链分布与GT密切相关,短链的含量越高,淀粉的GT越低。数量性状基因定位已经将GT相关基因定位在第6染色体的编码淀粉合酶IIa(SSⅡa)的alk基因位点。SSⅡa基因的若干功能性单核苷酸多态性(single nucleotide polymorphisms, SNPs)与GT和支链淀粉结构有关。这些SNPs已经用于标记辅助育种来改良稻米品质。提出了通过SSⅡa控制高或低GT的分子机理。

Research Progress on Genetics and Molecular Mechanism of Starch Gelatinization Temperature of Rice Grain

Gelatinization temperature (GT) is an important quality predictor that determines the cooking quality of rice. Low GT rice needs less energy input during cooking than high GT rice. The structure of amylopectin, especially its side-chain length distribution, has close relation to GT. The more amount of short chains, the lower starch GT. The quantitative trait locus (QTL) mapping has identified the alkali degenerate (alk) gene located on chromosome 6 as a major gene underlying the GT, which encodes the starch synthase IIa (SSⅡa). Functional single nucleotide polymorphisms (SNPs) found in SSⅡa are closely associated with GT and amylopectin structure. These SNPs are being used for marker assisted selection to improve rice quality. A molecular mechanism to control the variation in gelatinization temperature of rice starch by SSⅡa has also been put forward.