SummaryMesophyll conductance (gm) describes the ease with which CO2 passes from the sub‐stomatal cavities of the leaf to the primary carboxylase of photosynthesis, Rubisco. Increasing gm is suggested as a means to engineer increases in photosynthesis by increasing [CO2] at Rubisco, inhibiting oxygenation and accelerating carboxylation. Here, tobacco was transgenically up‐regulated with Arabidopsis Cotton Golgi‐related 3 (CGR3), a gene controlling methylesterification of pectin, as a strategy to increase CO2 diffusion across the cell wall and thereby increase gm. Across three independent events in tobacco strongly expressing AtCGR3, mesophyll cell wall thickness was decreased by 7%–13%, wall porosity increased by 75% and gm measured by carbon isotope discrimination increased by 28%. Importantly, field‐grown plants showed an average 8% increase in leaf photosynthetic CO2 uptake. Up‐regulating CGR3 provides a new strategy for increasing gm in dicotyledonous crops, leading to higher CO2 assimilation and a potential means to sustainable crop yield improvement.

中文翻译：

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通过在烟草中表达 AtCGR3 改变细胞壁孔隙度和厚度，在田间提高叶肉导度和叶片光合作用

摘要叶肉电导（G米）描述了 CO 的容易程度2从叶子的气孔下腔传递到光合作用的初级羧化酶 Rubisco。增加G米建议作为通过增加[CO2] 在 Rubisco，抑制氧化并加速羧化。在这里，烟草通过转基因上调拟南芥棉花高尔基体相关 3 (CGR3），一种控制果胶甲基酯化的基因，作为增加二氧化碳的策略2穿过细胞壁扩散，从而增加G米。在烟草领域的三个独立事件中强烈表达AtCGR3，叶肉细胞壁厚度减少7%~13%，细胞壁孔隙率增加75%，G米通过碳同位素辨别测量增加了28%。重要的是，田间种植的植物叶片光合二氧化碳平均增加了 8%2吸收。上调CGR3提供了一个新的策略来增加G米双子叶作物中，导致二氧化碳排放量更高2同化和可持续作物产量提高的潜在手段。