Transmission of reductive cues from the photosynthetic electron transport chain to redox-regulated proteins plays a crucial role in activating chloroplast metabolism. However, deciphering the role of their counterbalanced oxidative signals is challenging due to monitoring difficulties. Here, we demonstrate the light-depended redox modification of chloroplast-targeted 2-Cys peroxiredoxins and introduce peroxiredoxin-based biosensors to monitor photosynthetically-derived oxidative signals. By employing a set of genetically encoded biosensors, we show the induction of oxidative signals under habitual light intensities and their inverse relationship with NADPH levels, unraveling the combined activity of reducing and oxidizing signals in fine-tuning chloroplast metabolism. A faster increase in carbon assimilation rates during photosynthesis induction phase was measured in plants deficient in 2-Cys peroxiredoxins compared to wild-type, suggesting the involvement of oxidative signals in attenuating photosynthesis under variable light environments. We suggest that oxidative signals measured by peroxiredoxin-based biosensors reflect the limitation to photosynthesis imposed by the redox regulatory system.

中文翻译：

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系统监测 2-Cys 过氧化物还蛋白衍生的氧化还原信号揭示其在减弱碳同化速率中的作用

从光合电子传递链到氧化还原调节蛋白的还原线索的传输在激活叶绿体代谢中起着至关重要的作用。然而，由于监测困难，破译其平衡氧化信号的作用具有挑战性。在这里，我们展示了叶绿体靶向 2-Cys 过氧化还原蛋白的光依赖氧化还原修饰，并引入了基于过氧化还原蛋白的生物传感器来监测光合衍生的氧化信号。通过使用一组基因编码的生物传感器，我们展示了在习惯光强度下氧化信号的诱导及其与 NADPH 水平的反比关系，揭示了微调叶绿体代谢中还原和氧化信号的组合活动。与野生型相比，在缺乏 2-Cys 过氧化还原蛋白的植物中，光合作用诱导阶段碳同化速率的增加更快，这表明氧化信号在可变光环境下减弱光合作用。我们建议基于过氧还蛋白的生物传感器测量的氧化信号反映了氧化还原调节系统对光合作用的限制。