Improvement of photosynthetic efficiency by introduction of high kcat Rubisco from Poaseae.

通过引入来自禾本科的高 kcat Rubisco 来提高光合作用效率。

基本信息

批准号：
20580014
负责人：
FUKAYAMA Hiroshi
金额：
$ 2.91万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2011
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-20580014/
关键词：
酵素遺伝子光合成作物学 Rubisco 酵素特性遺伝子組換えイネ相同組換

项目摘要

The activity of Rubisco is a major limitation of photosynthetic CO_2 assimilation rate in C_3 plants. In order to find useful Rubisco for improvement of photosynthesis in rice under elevated CO_2, the catalytic turnover rate(k_<cat>) of Rubisco was analyzed in Poaceae including C_3 alpine plants, C_3 cold resistant plants and C_4 plants. Rubisco in these plants showed 1. 1-to 2. 8-fold higher k_<cat> than that in rice. Among plants analyzed, Rubisco in Festuca ovina, Phleum pratense and Sorghum showed relatively high k_<cat> to Kc. In our estimation, the expression of high k_<cat> Rubisco of F. ovina and S. bicolor in rice could significantly enhance CO_2 assimilation rates under elevated CO_2. We introduced the small subunit(RbcS) of Sorghum and it was found that Sorghum RbcS significantly enhances k_<cat> of Rubisco in transgenic rice(Oryza sativa). These results suggest that Rubisco in rice transformed with sorghum RbcS partially acquires the catalytic properties of sorghum Rubisco. Rubisco content in transgenic lines was significantly increased over wild type levels but Rubisco activation was slightly decreased. The expression of sorghum RbcS did not affect CO_2 assimilation rates under a range of CO_2 partial pressures. The J_<max>/V_<cmax> ratio was significantly lower in transgenic line compared to the nontransgenic plants. These observations suggest that the capacity of electron transport is not sufficient to support the increased Rubisco capacity in transgenic rice. Although the photosynthetic rate was not enhanced, the strategy presented in this study opens the way to engineering Rubisco for improvement of photosynthesis and productivity in the future.

Rubisco的活性是C_3植物中光合CO_2同化速率的主要局限性。为了找到有用的rubisco来改善升高的co_2下的水稻光合作用，在包括C_3高山植物，C_3冷耐药植物和C_4植物的毒虫中分析了Rubisco的催化转换率（K_ <CAT>）。这些植物中的Rubisco显示出比大米中的1-1至2。K_<CAT>高8倍。在分析的植物中，rubisco在festuca ovina中，植植物和高粱对KC的k_ <cat>显示出相对较高的k_ <cat>。在我们的估计中，大米中的卵虫和双色菌的高k_ <cat> rubisco的表达可以显着提高CO_2升高下的CO_2同化速率。我们引入了高粱的小亚基（RBC），发现高粱RBC在转基因大米（Oryza sativa）中显着增强了Rubisco的K_ <CAT>。这些结果表明，用高粱RBC转化的水稻中的Rubisco部分获得了高粱Rubisco的催化特性。在野生型水平上，转基因线中的Rubisco含量显着增加，但Rubisco激活略有下降。高粱RBC的表达不会影响CO_2的co_2部分压力下的CO_2同化速率。与非转基因植物相比，转基因线的J_ <max>/v_ <cmax>比率明显降低。这些观察结果表明，电子传输的能力不足以支持转基因大米中鲁比斯科的能力增加。尽管没有提高光合作用率，但这项研究中提出的策略为鲁比斯科工程提供了改善光合作用和生产率的方式。