14-PSIL Combining Algal and Plant Photosynthesis

在大多数植物中，生长速度受到光合作用过程中从大气中吸收二氧化碳并转化为糖的速度的限制。负责这一过程的第一步的酶Rubisco在目前大气中存在的二氧化碳水平下不能发挥其潜在的最大效率。如果水平高得多，光合作用就会增强，植物生产力就会更高。迫切需要提高作物生产率，为地球上不断增长的人口提供粮食。我们的项目解决了这个问题。我们正在研究一种存在于单细胞绿藻中的机制，这种机制会导致光合作用细胞内高浓度的二氧化碳(称为二氧化碳浓缩机制，或CCM)，使Rubisco能够以最高效率工作。在最初的CAPP1计划中，我们发现了关于这一机制的重要新信息，并使用新的快速方法确定了新的藻类基因和额外的调节成分，使CCM能够与称为蛋白核的特定微隔室一起工作。我们还成功地将其中一些成分引入到模式高等植物拟南芥中，并成功地引入了一种修饰形式的Rubisco，它可能有助于凝聚到类蛋白核中。CAPP2扩展的雄心勃勃的目标将是将CCM和类蛋白核在高级植物中的表达结合起来。首先，我们将继续鉴定藻类在细胞内实现高浓度二氧化碳所需的基因，并开发新的标记和传感器来揭示这些基因在高等植物中表达时的位置和活性。其次，我们将确定形成类蛋白核所需的额外调控元件，以及探索对Rubisco酶效率和光利用的影响。第三，我们将继续在我们的先进工厂模型中引入连续的组份，以“堆积”CCM组分的活动，并检查与CCM相关的类蛋白核形成和提高生产率的程度。这项工作将为植物和藻类如何从大气中获取和利用二氧化碳提供新的见解，对于预测和应对当前大气和气候的快速变化具有重要意义。这项工作还将有助于加强全球粮食安全的战略，因为它将指明提高作物生产率的新方法。

In most plants, growth rate is limited by the rate at which carbon dioxide (CO2) from the atmosphere is taken up and converted to sugars in the process of photosynthesis. The enzyme responsible for the first step in this process, Rubisco, does not work at its potential maximum efficiency at the current levels of carbon dioxide present in the atmosphere. If levels were much higher, photosynthesis would be increased and plant productivity would be higher. There is an immediate requirement for increased crop productivity to provide food for the rising population of the planet. Our project addresses this problem. We are studying a mechanism present in unicellular green algae that results in high concentrations of carbon dioxide inside their photosynthesising cells (called a CO2- Concentrating Mechanism, or CCM), enabling Rubisco to work at maximum efficiency. During the initial CAPP1 programme, we discovered important new information about this mechanism, and using new and rapid methods we have identified novel algal genes and additional regulatory components which allow the CCM to operate in association with a specific micro-compartment called a pyrenoid. We have also successfully introduced some of these components into a model higher plant, Arabidopsis, and also successfully introduced a modified form of Rubisco which may facilitate aggregation into the pyrenoid. The ambitious goals of the CAPP2 extension will be to combine the expression of the CCM and pyrenoid in the Advanced Plant. Firstly, we will continue to identify genes required by the algae to achieve high concentrations of carbon dioxide inside the cells, and develop new markers and sensors to reveal the location and activity of these genes when expressed in the higher plant. Secondly, we will identify additional regulatory elements needed to form a pyrenoid, as well as exploring the impact on Rubisco enzyme efficiency and light utilisation. Thirdly, we will continue to introduce successive components into our model Advanced Plant so as to "stack" up the activities of CCM components and examine the extent of pyrenoid formation and enhanced productivity associated with the CCM. This work will provide new insights into how plants and algae acquire and use carbon dioxide from the atmosphere, of great importance in predicting and coping with the current rapid changes in the atmosphere and hence in climate. The work will also contribute to strategies to increase global food security, because it will indicate new ways in which crop productivity can be increased.