Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University, 430070, Wuhan, China.
Nat Commun. 2023 Apr 25;14(1):2118. doi: 10.1038/s41467-023-37490-0.
The growth in world population, climate change, and resource scarcity necessitate a sustainable increase in crop productivity. Photosynthesis in major crops is limited by the inefficiency of the key CO-fixing enzyme Rubisco, owing to its low carboxylation rate and poor ability to discriminate between CO and O. In cyanobacteria and proteobacteria, carboxysomes function as the central CO-fixing organelles that elevate CO levels around encapsulated Rubisco to enhance carboxylation. There is growing interest in engineering carboxysomes into crop chloroplasts as a potential route for improving photosynthesis and crop yields. Here, we generate morphologically correct carboxysomes in tobacco chloroplasts by transforming nine carboxysome genetic components derived from a proteobacterium. The chloroplast-expressed carboxysomes display a structural and functional integrity comparable to native carboxysomes and support autotrophic growth and photosynthesis of the transplastomic plants at elevated CO. Our study provides proof-of-concept for a route to engineering fully functional CO-fixing modules and entire CO-concentrating mechanisms into chloroplasts to improve crop photosynthesis and productivity.
世界人口的增长、气候变化和资源短缺要求作物生产力的可持续提高。主要作物的光合作用受到关键的 CO 固定酶 Rubisco 效率低下的限制，这是由于其羧化速率低且对 CO 和 O 的区分能力差。在蓝细菌和变形菌中，羧化体作为中央 CO 固定细胞器发挥作用，可提高围绕包被的 Rubisco 的 CO 水平，从而增强羧化作用。将羧化体工程改造为作物叶绿体，以提高光合作用和作物产量，这一方法越来越受到关注。在这里，我们通过转化源自一种变形菌的九个羧化体遗传成分，在烟草叶绿体中产生形态正确的羧化体。叶绿体表达的羧化体显示出与天然羧化体相当的结构和功能完整性，并支持转叶绿体植物在高 CO 下的自养生长和光合作用。我们的研究为工程改造具有完整功能的 CO 固定模块和整个 CO 浓缩机制进入叶绿体以提高作物光合作用和生产力提供了概念验证。
