Abstract:

With the increase of population and the decrease of cultivated land, human demand for food is increasing. Therefore, it is particularly important to ensure adequate food supply. Photosynthesis is the most important chemical reaction on the earth, which converts inorganic matter into organic matter through light reaction and carbon assimilation. More than 90% of plant dry matter comes from the carbon fixation reaction of photosynthesis. The assimilated organic matter of photosynthesis is the material basis for the formation of crop yield. Therefore, improving the efficiency of crop light energy utilization is an important way to improve crop yield. In recent years, the rapid development of synthetic biology in the fields of energy, materials, health and environment has provided new opportunities for improving plant photosynthetic efficiency. This paper highlights the research progress of synthetic biology in improving the carbon assimilation efficiency of photosynthesis, mainly focusing on: (1) Improving the carboxylation activity of Rubisco enzymes, including identifying Rubisco enzymes with high carboxylation activity, optimizing gene expression regulatory sequences on Rubisco, and co-expressing Rubisco chaperone proteins; (2) Introducing CO₂ concentrating mechanisms, including C₄ photosynthetic enzymes, cyanobacterial transporter proteins, and cyanobacterial carboxysomes; (3) Reducing photorespiration through the introduction of four photorespiratory branches: chloroplast glycerate bypass, peroxisomal glycerate bypass, chloroplast glycolate oxidation bypass, and 3-hydroxypropionate bypass, and the exploration of new branches of photorespiration; Finally, the new photosynthetic carbon fixation circuit is discussed. The design, transformation, optimization and reorganization of photosynthetic carbon assimilation module through synthetic biology will effectively improve the efficiency of carbon assimilation and ultimately improve crop yield.

Key words: photosynthesis, photosynthetic efficiency, synthetic biology, carbon assimilation

摘要：

随着人口增多及耕地面积的减少，人类对粮食的需求日益增加，因此保障足够的粮食供给尤为重要。光合作用通过光反应和碳同化把无机物转换成有机物，是地球上最重要的化学反应。90%以上的植物干物质来源于光合作用固碳反应，光合作用同化的有机物是作物产量形成的物质基础，因此提高作物光能利用效率是提高作物产量的重要途径。近年来，合成生物学在能源、材料、健康和环境等多领域的快速发展，为提高植物光合效率提供了新的机遇。本文着重讨论了合成生物学在提高光合作用碳同化效率方面的研究进展，主要集中在提高Rubisco酶的羧化活性、引进CO₂浓缩机制、降低光呼吸等方面；最后，对新型光合固碳回路进行探讨，通过合成生物学对光合作用碳同化模块进行设计、改造、优化和重组，必将有效提高碳同化效率，最终提高作物产量。

关键词: 光合作用, 光合作用效率, 合成生物学, 碳同化