Starch content in leaf sheath controlled by CO2-responsive CCT protein is a potential determinant of photosynthetic capacity in rice
Starch content in leaf sheath controlled by CO2-responsive CCT protein is a potential determinant of photosynthetic capacity in rice
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CO2响应性CCT蛋白控制的叶鞘淀粉含量是水稻光合能力的潜在决定因素
DOI：
10.1093/pcp/pcw142
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Fukayama H
中科院分区：
文献类型：
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作者：
Morita R.;Inoue K.;Ikeda K.;Hatanaka T.;Misoo S.;Fukayama H
CO2响应CCT蛋白(CRCT)是营养器官，特别是水稻叶鞘中淀粉合成的正向调节因子。在这项研究中，我们利用CRCT过表达和RNA干扰技术，分析了在常温(38 pa)和高CO2(100 pa)条件下生长的转基因水稻叶片中淀粉水平对叶片光合作用速率的影响。在两种CO2条件下，叶鞘中的淀粉含量与CRCT的表达水平有明显的相关性。相反，在高CO2条件下生长的击倒系叶片中的可溶性糖和淀粉含量显著增加。CRCT的过度表达或RNAi敲除对在CO2环境下生长的转基因株系的光合作用没有造成很大的影响。然而，在CO2浓度升高的条件下，高表达品系的光合作用速率增强，而低表达品系的光合作用速率显著降低。光合作用速率与氮素含量呈弱相关，与总非结构性碳水化合物含量呈负相关。因此，受CRCT控制的叶鞘淀粉合成能力可以间接影响高CO2条件下水稻叶片的碳水化合物含量，进而影响叶片的光合作用速率。
CO2-responsive CCT protein (CRCT) is the suggested positive regulator of starch synthesis in vegetative organs, particularly the leaf sheath of rice. In this study, we analyzed the effects of the starch level in the leaf sheath on the photosynthetic rate in the leaf blade usingCRCToverexpression and RNA interference (RNAi) knockdown transgenic rice grown under ambient (38 Pa) or elevated (100 Pa) CO2conditions. In leaf sheath, the starch content was markedly changed in relation toCRCTexpression levels under both CO2conditions. In contrast, the soluble sugar and starch contents of the leaf blade were markedly increased in the knockdown line grown under elevated CO2conditions. The overexpression or RNAi knockdown ofCRCTdid not cause large effects on the photosynthetic rate of the transgenic lines grown under ambient CO2condition. However, the photosynthetic rate of the overexpression line was enhanced, while that of the knockdown line was substantially decreased under elevated CO2conditions. These photosynthetic rates were weakly correlated with the nitrogen contents and negatively correlated with the total non-structural carbohydrate contents. Thus, the capacity for starch synthesis in leaf sheath, which is controlled byCRCT, can indirectly affect the carbohydrate content, and then the photosynthetic rate in the leaf blade of rice grown under elevated CO2conditions.