CO2 Responsive CCT Protein Stimulates the Ectopic Expression of Particular Starch Biosynthesis-Related Enzymes, which Markedly Change the Structure of Starch in the Leaf Sheaths of Rice
CO2 Responsive CCT Protein Stimulates the Ectopic Expression of Particular Starch Biosynthesis-Related Enzymes, which Markedly Change the Structure of Starch in the Leaf Sheaths of Rice
复制标题
CO2 响应性 CCT 蛋白刺激特定淀粉生物合成相关酶的异位表达，从而显着改变水稻叶鞘中淀粉的结构
DOI：
10.1093/pcp/pcz008
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发表时间：
2019
影响因子：
4.9
通讯作者：
Hiroshi Fukayama
中科院分区：
文献类型：
--
作者：
Ryutaro Morita;Naoko Croft;Naoki Shibatani;Satoko Miura;Yuko Hosaka;Naoko F. Oitome;Ken-ichi Ikeda;Naoko Fujita;Hiroshi Fukayama
CO2 响应性 CCT 蛋白（CRCT）被认为是水稻叶鞘中淀粉生物合成的正调节因子，调节淀粉生物合成相关基因的表达水平。本研究探讨CRCT表达水平对淀粉生物合成相关酶表达及淀粉品质的影响。利用非变性PAGE/活性染色和免疫印迹，我们发现淀粉合酶I、分支酶I、分支酶IIa、异淀粉酶1和磷酸化酶1的蛋白水平与CRCT转基因株系的叶鞘中的CRCT表达水平很大程度上相关。相反，CRCT表达水平很大程度上不影响叶片和胚乳组织中淀粉生物合成相关酶的表达水平和/或活性。对叶鞘中淀粉链长分布的分析表明，聚合度为5至14的短链在过表达品系中增加，而在敲低品系中减少。在过表达株系中，叶鞘中淀粉的直链淀粉含量大大增加。相反，过表达株系叶鞘中淀粉支链淀粉的分子量与非转基因水稻相比没有变化。这些结果表明CRCT可以通过调节特定淀粉生物合成相关酶的表达来控制叶鞘中淀粉的质量和数量。
CO2-responsive CCT protein (CRCT) is suggested to be a positive regulator of starch biosynthesis in the leaf sheaths of rice, regulating the expression levels of starch biosynthesis-related genes. In this study, the effects ofCRCTexpression levels on the expression of starch biosynthesis-related enzymes and the quality of starch were studied. Using native-PAGE/activity staining and immunoblotting, we found that the protein levels of starch synthase I, branching enzyme I, branching enzyme IIa, isoamylase 1 and phosphorylase 1 were largely correlated with theCRCTexpression levels in the leaf sheaths ofCRCTtransgenic lines. In contrast, theCRCTexpression levels largely did not affect the expression levels and/or activities of starch biosynthesis-related enzymes in the leaf blades and endosperm tissues. The analysis of the chain-length distribution of starch in the leaf sheaths showed that short chains with a degree of polymerization from 5 to 14 were increased in the overexpression lines but decreased in the knockdown lines. The amylose content of starch in the leaf sheath was greatly increased in the overexpression lines. In contrast, the molecular weight of the amylopectin of starch in the leaf sheath of overexpression lines did not change compared with those of the non-transgenic rice. These results suggest thatCRCTcan control the quality and the quantity of starch in the leaf sheath by regulating the expression of particular starch biosynthesis-related enzymes.