Amyloplast Membrane Protein SUBSTANDARD STARCH GRAIN6 Controls Starch Grain Size in Rice Endosperm
Amyloplast Membrane Protein SUBSTANDARD STARCH GRAIN6 Controls Starch Grain Size in Rice Endosperm
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DOI：
10.1104/pp.15.01811
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发表时间：
2016-03-01
期刊：
影响因子：
7.4
通讯作者：
Sakamoto, Wataru
中科院分区：
文献类型：
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作者：
Matsushima, Ryo;Maekawa, Masahiko;Sakamoto, Wataru
淀粉是一种在生物学和商业上都很重要的葡萄糖聚合物。淀粉在造粉体内部形成淀粉粒（SGs）。淀粉粒的大小因植物种类而异，是淀粉工业应用的最重要因素之一。关于调控淀粉粒大小的遗传因素的信息有限。在这项研究中，我们报道了水稻（Oryza sativa）突变体不达标淀粉粒6（ssg6），其胚乳中形成增大的淀粉粒。从开花后3天开始观察到增大的淀粉粒。在胚乳发育过程中，一些较小的淀粉粒出现，并与增大的淀粉粒在同一细胞中共存。ssg6突变也影响花粉中的淀粉粒形态。通过图位克隆和微阵列分析鉴定出SSG6基因。SSG6编码一种与转氨酶同源的蛋白质。SSG6与其他水稻同源物的不同之处在于它具有一个跨膜结构域。SSG6 - 绿色荧光蛋白定位在水稻胚乳、花粉和果皮中围绕淀粉粒的造粉体膜上。这项研究的结果表明，SSG6是一种控制淀粉粒大小的新型蛋白质。SSG6将成为未来淀粉育种和应用的有用分子工具。
Starch is a biologically and commercially important polymer of glucose. Starch is organized into starch grains (SGs) inside amyloplasts. The SG size differs depending on the plant species and is one of the most important factors for industrial applications of starch. There is limited information on genetic factors regulating SG sizes. In this study, we report the rice (Oryza sativa) mutant substandard starch grain6 (ssg6), which develops enlarged SGs in endosperm. Enlarged SGs are observed starting at 3 d after flowering. During endosperm development, a number of smaller SGs appear and coexist with enlarged SGs in the same cells. The ssg6 mutation also affects SG morphologies in pollen. The SSG6 gene was identified by map-based cloning and microarray analysis. SSG6 encodes a protein homologous to aminotransferase. SSG6 differs from other rice homologs in that it has a transmembrane domain. SSG6-green fluorescent protein is localized in the amyloplast membrane surrounding SGs in rice endosperm, pollen, and pericarp. The results of this study suggest that SSG6 is a novel protein that controls SG size. SSG6 will be a useful molecular tool for future starch breeding and applications.