School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China.
Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai, China.
Nat Commun. 2020 Jun 26;11(1):3238. doi: 10.1038/s41467-020-17056-0.
The challenge of monitoring in planta dynamic changes of NADP(H) and NAD(H) redox states at the subcellular level is considered a major obstacle in plant bioenergetics studies. Here, we introduced two circularly permuted yellow fluorescent protein sensors, iNAP and SoNar, into Arabidopsis thaliana to monitor the dynamic changes in NADPH and the NADH/NAD ratio. In the light, photosynthesis and photorespiration are linked to the redox states of NAD(P)H and NAD(P) pools in several subcellular compartments connected by the malate-OAA shuttles. We show that the photosynthetic increases in stromal NADPH and NADH/NAD ratio, but not ATP, disappear when glycine decarboxylation is inhibited. These observations highlight the complex interplay between chloroplasts and mitochondria during photosynthesis and support the suggestions that, under normal conditions, photorespiration supplies a large amount of NADH to mitochondria, exceeding its NADH-dissipating capacity, and the surplus NADH is exported from the mitochondria to the cytosol through the malate-OAA shuttle.
监测植物生物能学研究中 NADP(H)和 NAD(H)氧化还原状态亚细胞水平动态变化的挑战被认为是一个主要障碍。在这里，我们将两个环状排列的黄色荧光蛋白传感器，iNAP 和 SoNar，引入拟南芥中，以监测 NADPH 和 NADH/NAD 比的动态变化。在光下，光合作用和光呼吸与通过苹果酸-OAA 穿梭连接的几个亚细胞隔室中的 NAD(P)H 和 NAD(P)池的氧化还原状态相关联。我们表明，当甘氨酸脱羧作用受到抑制时，基质 NADPH 和 NADH/NAD 比的光合作用增加，但 ATP 不会增加。这些观察结果强调了光合作用过程中叶绿体和线粒体之间的复杂相互作用，并支持以下观点，即在正常条件下，光呼吸为线粒体提供大量的 NADH，超过其 NADH 耗散能力，多余的 NADH 通过苹果酸-OAA 穿梭从线粒体输出到细胞质。
