Potential metabolic mechanisms for inhibited chloroplast nitrogen assimilation under high CO2.
Potential metabolic mechanisms for inhibited chloroplast nitrogen assimilation under high CO2.
复制标题
高CO2条件下抑制叶绿体氮同化的潜在代谢机制
DOI：
10.1093/plphys/kiab345
复制
发表时间：
2021-11-03
期刊：
影响因子：
7.4
通讯作者：
Zhu XG
中科院分区：
文献类型：
--
作者：
Zhao HL;Chang TG;Xiao Y;Zhu XG
改善光合作用被认为是显著提高作物产量潜力的主要和可行的选择。大气中CO2浓度的增加通常会刺激光合作用和作物产量，但会降低主要C3谷类作物的蛋白质含量。作物中蛋白质含量的减少限制了CO2升高对作物产量的好处，并影响了它们对人类的营养价值。为了支持光合氮同化及其与光合碳代谢的复杂相互作用的研究，作物改良，我们建立了一个植物初级代谢的动力学系统模型，包括卡尔文-本森循环，光呼吸途径，淀粉合成，糖酵解-异生，三羧酸循环，叶绿体氮同化。该模型成功地捕捉到了光合CO2净吸收速率（A）、呼吸速率和氮同化速率对不同光照和CO2水平的响应。然后，我们用这个模型来预测在CO2浓度升高的氮同化抑制。利用该模型进一步探讨了CO2浓度升高抑制氮同化的可能机制。模拟表明，增加α-酮戊二酸的供应是一种潜在的策略，以保持高速率的氮同化CO2浓度升高。该模型可以作为一种启发式工具，支持光合作用，呼吸和氮同化之间的相互作用的研究。它还提供了一个基本框架，以支持设计和工程的C3植物初级代谢，提高光合效率和氮同化在未来的高CO2世界。C3初级代谢动力学系统模型的模拟表明，减少供应的还原当量和2-酮基谷氨酸导致减少氮同化CO2浓度升高。
Improving photosynthesis is considered a major and feasible option to dramatically increase crop yield potential. Increased atmospheric CO2 concentration often stimulates both photosynthesis and crop yield, but decreases protein content in the main C3 cereal crops. This decreased protein content in crops constrains the benefits of elevated CO2 on crop yield and affects their nutritional value for humans. To support studies of photosynthetic nitrogen assimilation and its complex interaction with photosynthetic carbon metabolism for crop improvement, we developed a dynamic systems model of plant primary metabolism, which includes the Calvin–Benson cycle, the photorespiration pathway, starch synthesis, glycolysis–gluconeogenesis, the tricarboxylic acid cycle, and chloroplastic nitrogen assimilation. This model successfully captures responses of net photosynthetic CO2 uptake rate (A), respiration rate, and nitrogen assimilation rate to different irradiance and CO2 levels. We then used this model to predict inhibition of nitrogen assimilation under elevated CO2. The potential mechanisms underlying inhibited nitrogen assimilation under elevated CO2 were further explored with this model. Simulations suggest that enhancing the supply of α-ketoglutarate is a potential strategy to maintain high rates of nitrogen assimilation under elevated CO2. This model can be used as a heuristic tool to support research on interactions between photosynthesis, respiration, and nitrogen assimilation. It also provides a basic framework to support the design and engineering of C3 plant primary metabolism for enhanced photosynthetic efficiency and nitrogen assimilation in the coming high-CO2 world. Simulations with a dynamic systems model of C3 primary metabolism show that the decreased supply of reducing equivalent and 2-oxoglutaric acid cause decreased nitrogen assimilation under elevated CO2.
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影响因子：
6.9
作者：
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