Sorghum is one of the most important crops providing food and feed in many of the world's harsher environments. Sorghum utilizes the C₄ pathway of photosynthesis in which a biochemical carbon-concentrating mechanism results in high CO₂ assimilation rates. Overexpressing the Rieske FeS subunit of the Cytochrome b₆f complex was previously shown to increase the rate of photosynthetic electron transport and stimulate CO₂ assimilation in the model C₄ plant Setaria viridis. To test whether productivity of C₄ crops could be improved by Rieske overexpression, we created transgenic Sorghum bicolor Tx430 plants with increased Rieske content. The transgenic plants showed no marked changes in abundances of other photosynthetic proteins or chlorophyll content. The steady-state rates of electron transport and CO₂ assimilation did not differ between the plants with increased Rieske abundance and control plants, suggesting that Cytochrome b₆f is not the only factor limiting electron transport in sorghum at high light and high CO₂. However, faster responses of non-photochemical quenching as well as an elevated quantum yield of Photosystem II and an increased CO₂ assimilation rate were observed from the plants overexpressing Rieske during the photosynthetic induction, a process of activation of photosynthesis upon the dark–light transition. As a consequence, sorghum with increased Rieske content produced more biomass and grain when grown in glasshouse conditions. Our results indicate that increasing Rieske content has potential to boost productivity of sorghum and other C₄ crops by improving the efficiency of light utilization and conversion to biomass through the faster induction of photosynthesis.

中文翻译：

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更快的光合作用诱导增加了温室种植的过表达 Rieske FeS 的转基因双色高粱的生物量和谷物产量

高粱是世界上许多严酷环境中提供食物和饲料的最重要作物之一。高粱利用C ₄光合作用途径，其中生化碳浓缩机制导致高CO ₂同化率。细胞色素b ₆ f复合物的 Rieske FeS 亚基的过表达先前显示可提高光合电子传输速率并刺激模型 C ₄植物Setaria viridis中的 CO ₂同化。为了测试 C ₄作物的生产力是否可以通过 Rieske 过表达来提高，我们创建了转基因双色高粱Rieske 含量增加的 Tx430 植物。转基因植物在其他光合蛋白的丰度或叶绿素含量方面没有显着变化。_{电子传输和 CO 2}同化的稳态速率在 Rieske 丰度增加的植物和对照植物之间没有差异，这表明细胞色素b ₆ f不是限制高粱在高光和高 CO _{2条件下电子传输的唯一因素}。然而，非光化学猝灭的更快响应以及光系统 II 的量子产率增加和 CO _2增加在光合作用诱导过程中，从过表达 Rieske 的植物中观察到同化率，光合作用是在暗光转换时激活光合作用的过程。因此，在温室条件下生长时，里斯克含量增加的高粱会产生更多的生物量和谷物。我们的结果表明，增加 Rieske 含量有可能通过提高光利用效率和通过更快的光合作用诱导转化为生物质来提高高粱和其他 C _{4作物的生产力。}