C₄ crops of agricultural importance all belong to the NADP‐malic enzyme (ME) subtype, and this subtype has been the template for C₄ introductions into C₃ crops, like rice, to improve their productivity. However, the ATP cost for the C₄ cycle in both NADP‐ME and NAD‐ME subtypes accounts for > 40% of the total ATP requirement for CO₂ assimilation. These high ATP costs, and the associated need for intense cyclic electron transport and low intrinsic quantum yield , are major constraints in realizing strong improvements of canopy photosynthesis and crop productivity. Based on mathematical modelling, we propose a C₄ ideotype that utilizes low chloroplastic ATP requirements present in the nondomesticated phosphoenolpyruvate carboxykinase (PEP‐CK) subtype. The ideotype is a mixed form of NAD(P)‐ME and PEP‐CK types, requires no cyclic electron transport under low irradiances, and its theoretical is c. 25% higher than that of a C₄ crop type. Its cell‐type‐specific ATP and NADPH requirements can be fulfilled by local energy production. The ideotype is projected to have c. 10% yield advantage over NADP‐ME‐type crops and > 50% advantage over C₃ counterparts. The ideotype provides a unique (theoretical) case where could be improved, thereby paving a new avenue for improving photosynthesis in both C₃ and C₄ crops.

中文翻译：

---

利用 C4 亚型之间能量收支的差异来提高作物生产力

具有农业重要性的C ₄作物都属于 NADP-苹果酸酶 (ME) 亚型，该亚型已成为将 C ₄引入 C ₃作物（如水稻）以提高其生产力的模板。然而，在 NADP-ME 和 NAD-ME 亚型中，C ₄循环的 ATP 成本占 CO ₂同化所需的总 ATP 需求的 40% 以上。这些高 ATP 成本，以及对强烈循环电子传输和低固有量子产率的相关需求，是实现冠层光合作用和作物生产力大幅提高的主要制约因素。基于数学建模，我们提出了一个 C ₄利用非驯化磷酸烯醇丙酮酸羧激酶 (PEP-CK) 亚型中存在的低叶绿体 ATP 需求的理想型。ideotype 是 NAD(P)-ME 和 PEP-CK 类型的混合形式，在低辐照度下不需要循环电子传输，其理论值为c。比 C ₄作物类型高 25%。其细胞类型特定的 ATP 和 NADPH 需求可以通过当地的能源生产来满足。意识形态预计有c。与 NADP-ME 型作物相比，产量优势 10%，与 C ₃对应物相比，产量优势 > 50%。理念型提供了一个可以改进的独特（理论）案例，从而为改善两种 C 中的光合作用铺平了新的途径₃和 C ₄作物。