Formation of Semi-compound C-Type Starch Granule in High-Amylose Rice Developed by Antisense RNA Inhibition of Starch-Branching Enzyme
Formation of Semi-compound C-Type Starch Granule in High-Amylose Rice Developed by Antisense RNA Inhibition of Starch-Branching Enzyme
复制标题
淀粉分支酶反义RNA抑制高直链淀粉半复合C型淀粉颗粒的形成
DOI：
10.1021/jf1024533
复制
发表时间：
2010-10-27
影响因子：
6.1
通讯作者：
Liu, Qiaoquan
中科院分区：
文献类型：
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作者：
Wei, Cunxu;Qin, Fengling;Liu, Qiaoquan
高直链淀粉和抗性淀粉的淀粉颗粒通常具有不规则的形态和特殊的晶体结构，但其在籽粒发育过程中的形成尚不清楚。在我们以前的研究中，我们已经获得了富含直链淀粉和RS的转基因水稻品系（TRS），它含有显示C型晶体结构的半复合淀粉。本研究利用光学显微镜、扫描电镜、透射电镜和X射线粉末衍射等技术，对TRS胚乳发育过程中半复合C型淀粉粒的形成进行了研究。结果表明，TRS淀粉亚颗粒在淀粉体中独立起始，在淀粉粒发育的早期，其淀粉亚颗粒与野生型淀粉亚颗粒相似，均具有中央种脐，并呈A型晶体。但随着胚乳的发育，TRS胚乳淀粉中直链淀粉含量增加，B型淀粉晶体沉积在亚颗粒的周边，随后相邻的亚颗粒融合在一起，最后形成一个连续的外层带，将淀粉颗粒的整个周边包裹起来。据此，提出了半复合C型淀粉颗粒形成的机理模型。
Cereal starch granules with high-amylose and resistant starch (RS) always show irregular morphology and special crystalline structure, but their formation during grain development is not yet clear. In our previous studies, we had generated a transgenic rice line (TRS) enriched with amylose and RS, which contained semi-compound starch showing a C-type crystalline structure. In this study, the formation of semi-compound C-type starch granule during TRS endosperm development was carefully investigated with light, scanning electron, and transmission electron microscopes and X-ray powder diffraction. The results showed that the TRS starch subgranules, each with a central hilum, were individually initiated in amyloplast and showed an A-type crystal at the early stage of starch granule development, which was similar to that in its wild type. However, with the endosperm development, the amylose content in TRS endosperm starch increased and the B-type starch crystal was deposited in the periphery of subgranules; then, the adjacent subgranules fused together and finally formed a continuous outer layer band surrounding the entire circumference of the starch granule. Accordingly, a mechanistic model for the formation of semi-compound C-type starch granules is proposed.