Global demand for food may rise by 60% mid-century. A central challenge is to meet this need using less land in a changing climate. Nearly all crop carbon is assimilated through Rubisco, which is catalytically slow, reactive with oxygen, and a major component of leaf nitrogen. Developing more efficient forms of Rubisco, or engineering CO₂ concentrating mechanisms into C₃ crops to competitively repress oxygenation, are major endeavors, which could hugely increase photosynthetic productivity (≥ 60%). New technologies are bringing this closer, but improvements remain in the discovery phase and have not been reduced to practice. A simpler shorter-term strategy that could fill this time gap, but with smaller productivity increases (c. 10%) is to increase leaf Rubisco content. This has been demonstrated in initial field trials, improving the productivity of C₃ and C₄ crops. Combining three-dimensional leaf canopies with metabolic models infers that a 20% increase in Rubisco increases canopy photosynthesis by 14% in sugarcane (C₄) and 9% in soybean (C₃). This is consistent with observed productivity increases in rice, maize, sorghum and sugarcane. Upregulation of Rubisco is calculated not to require more nitrogen per unit yield and although achieved transgenically to date, might be achieved using gene editing to produce transgene-free gain of function mutations or using breeding.

中文翻译：

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现在增加 Rubisco 作为一种在不降低氮利用效率的情况下增强光合作用和生产力的简单手段


全球对食品的需求可能会在本世纪中叶增长 60%。一个主要挑战是在不断变化的气候中使用更少的土地来满足这一需求。几乎所有的作物碳都通过 Rubisco 被同化，Rubisco 的催化速度很慢，与氧气反应，是叶氮的主要成分。开发更有效的 Rubisco 形式，或将 CO₂ 浓缩机制设计成 C₃ 作物以竞争性地抑制氧合，是一项重大努力，可以大大提高光合作用生产力 （≥ 60%）。新技术使这一目标更近了一步，但改进仍处于发现阶段，尚未付诸实践。一个更简单的短期策略可以填补这个时间空白，但生产率提高幅度较小（约 10%），即增加叶子 Rubisco 含量。这在最初的田间试验中得到了证明，提高了 C₃ 和 C₄ 作物的生产力。将三维叶冠与代谢模型相结合，推断 Rubisco 增加 20% 会增加甘蔗 （C₄） 和 9% 大豆 （C₃） 的冠层光合作用。这与观察到的水稻、玉米、高粱和甘蔗的生产力提高一致。Rubisco 的上调计算为每单位产量不需要更多的氮，尽管迄今为止通过转基因实现，但可能使用基因编辑产生无转基因功能突变的增益或使用育种来实现。