Improvement of photosynthesis by modification of light harvesting systems

通过修改光捕获系统来改善光合作用

基本信息

批准号：
12354009
负责人：
TANAKA Ayumi
金额：
$ 24.19万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12354009/
关键词：
CAO photosynthesis chlorophyll light energy light-harvesting apparatus

项目摘要

Photosynthetic organisms can proceed photosynthesis under various light conditions on the Earth. Plants employ two strategies to adapt light intensities, one is the dissipation of excess light energy as heat and the other mechanism is the regulation of light harvesting apparatus. Capturing light energy is the first step of photosynthesis and the regulation of the amount of harvesting light energy directly influences the rate of photosynthesis. There are many reports on the employment of genetic engineering for the improvement of agricultural production . Most typical successes were to improve the resistances to virus infection and insect attack. However, these genetic engineerings do not increase productivity itself. In order to increase the productivity of the plants, the ability of photosynthesis must be modified. The aims of this project are 1) to clarify the mechanisms of the acclimation of antenna size to light intensities, 2) modification of antenna size to improve productivities. Green plants have large antenna size under low light conditions in order to capture light energy for photosynthesis. In this case, the level of CAO mRNA was high and chlorophyll b was actively synthesized. However, in CAO over expressed lines of Arabidopsis thaliana, the level of CAO mRNA and the antenna size was almost same under wide range of light intensities. We concluded from the above experiments that CAO plays a central role in regulating the antenna size under various light intensities. We also found CAO over-expressed mutants grow well under low light intensities compared to wild type. It indicates that modifications of photosynthesis are potentially powerful tool to increase the productivities of the plants.

光合生物可以在地球上各种光照条件下进行光合作用。植物采用两种策略来适应光强度，一种是将多余的光能以热量的形式耗散，另一种机制是光捕获装置的调节。捕获光能是光合作用的第一步，光能捕获量的调节直接影响光合作用的速率。关于利用基因工程改进农业生产的报道有很多。最典型的成功是提高对病毒感染和昆虫攻击的抵抗力。然而，这些基因工程本身并不能提高生产力。为了提高植物的生产力，必须改变光合作用的能力。该项目的目的是 1) 阐明天线尺寸适应光强度的机制，2) 修改天线尺寸以提高生产率。绿色植物在弱光条件下具有较大的天线尺寸，以捕获光能进行光合作用。在这种情况下，CAO mRNA 水平较高，叶绿素 b 合成活跃。然而，在CAO过表达的拟南芥品系中，在宽范围的光强度下，CAO mRNA水平和触角尺寸几乎相同。我们从上述实验得出结论，CAO 在调节不同光强下的天线尺寸方面发挥着核心作用。我们还发现与野生型相比，CAO 过表达突变体在低光强度下生长良好。它表明光合作用的改变是提高植物生产力的潜在强大工具。