云南野生稻籽粒淀粉合成关键酶活性测定

Activity assay of grain starch synthesis key enzymes in wild rice species of Yunnan

为研究云南3种野生稻直链淀粉合成机制并利用其直链淀粉含量较低的优良品质,以云南3种野生稻和4种当地栽培稻为材料,研究野生稻灌浆期籽粒4种淀粉合成关键酶(包括ADPG焦磷酸化酶、可溶性淀粉合成、颗粒凝结型淀粉合成酶、淀粉分支酶)活性变化。结果表明,野生稻中4种淀粉合成酶的变化趋势与栽培稻相似,但活性有较大差别。颗粒凝结型淀粉合成酶的活性与直链淀粉含量呈正相关,说明在野生稻中同样是由颗粒凝结型淀粉合成酶控制直链淀粉的合成。同时发现在同一灌浆期,同种材料中可溶性淀粉合成酶和淀粉分支酶的活性变化呈相反趋势,推测这两种酶之间可能在淀粉合成过程中存在某种反馈调节机制。

In order to investigate the amylose synthesis mechanism of the three wild rice species originating from Yunnan so as to utilize the good quality trait of the low amylose content of these wild rice species, four key enzymes（ADPG pyrophosphorylase （ADPGP）, soluble starch synthase （SSS）, granule bound starch synthase （ GBSS）, starch branching enzyme（Q-enzyme）） activities in three wild rice species and four cultivar rice varieties of Yunnan were assayed during grain filling stages. The result indicated that four key enzymes had similar change trend, but had big differences in the activity among the different wild rice species and the cultivars. It was found that GBSS activity assay in wild rice also had positive relation with amylose content. This indicted that in wild rice the seed amylsoe synthesis is also controlled by granule bound starch synthase. It is also found that SSS and Q-enzyme showed opposition change trend in terms of activity during the grain filling stage. It may suggest these two enzymes had some feedback suppression effect on regulation of starch synthesis.