Mutation of the plastidial α-glucan phosphorylase gene in rice affects the synthesis and structure of starch in the endosperm
Mutation of the plastidial α-glucan phosphorylase gene in rice affects the synthesis and structure of starch in the endosperm
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DOI：
10.1105/tpc.107.054007
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发表时间：
2008-07-01
期刊：
影响因子：
11.6
通讯作者：
Nakamura, Yasunori
中科院分区：
文献类型：
--
作者：
Satoh, Hikaru;Shibahara, Kensuke;Nakamura, Yasunori
质体磷酸化酶（Pho 1）占水稻种子发育中总磷酸化酶活性的96%。从N-甲基-N-亚硝基脲处理诱导的突变体股票，我们确定了植物与突变的Pho 1基因缺陷的Pho 1。引人注目的是，这些突变体的成熟种子的大小和淀粉含量表现出相当大的变化，从萎缩到正常。损失的Pho 1引起较小的淀粉颗粒积累和修改的支链淀粉结构。单个种子的形态和生化表型的变化是共同的所有15 pho 1独立纯合突变株系研究，表明这种表型是完全由遗传缺陷引起的。pho 1突变的表型是温度依赖性的。虽然在30摄氏度下生长的突变体植物在成熟时主要产生饱满的种子，但在20摄氏度下生长的植物的大多数种子都是皱缩的，其中显着比例显示淀粉积累严重减少。这些结果强烈表明，Pho 1在低温下水稻胚乳淀粉合成中起着至关重要的作用，并且一个或多个其他因素可以在高温下补充Pho 1的功能。
Plastidial phosphorylase (Pho1) accounts for; 96% of the total phosphorylase activity in developing rice (Oryza sativa) seeds. From mutant stocks induced by N-methyl-N-nitrosourea treatment, we identified plants with mutations in the Pho1 gene that are deficient in Pho1. Strikingly, the size of mature seeds and the starch content in these mutants showed considerable variation, ranging from shrunken to pseudonormal. The loss of Pho1 caused smaller starch granules to accumulate and modified the amylopectin structure. Variation in the morphological and biochemical phenotype of individual seeds was common to all 15 pho1-independent homozygous mutant lines studied, indicating that this phenotype was caused solely by the genetic defect. The phenotype of the pho1 mutation was temperature dependent. While the mutant plants grown at 30 degrees C produced mainly plump seeds at maturity, most of the seeds from plants grown at 20 degrees C were shrunken, with a significant proportion showing severe reduction in starch accumulation. These results strongly suggest that Pho1 plays a crucial role in starch biosynthesis in rice endosperm at low temperatures and that one or more other factors can complement the function of Pho1 at high temperatures.