Saini Deepak, Bharath Pulimamidi, Gahir Shashibhushan, Raghavendra Agepati S
School of Life Sciences, Department of Plant Sciences, University of Hyderabad, Hyderabad, 500046 India.
Physiol Mol Biol Plants. 2023 Dec;29(12):1851-1861. doi: 10.1007/s12298-023-01388-4. Epub 2023 Nov 22.
Photorespiration, an essential component of plant metabolism, was upregulated under abiotic stress conditions, such as high light or drought. One of the signals for such upregulation was the rise in reactive oxygen species (ROS). Photorespiration was expected to mitigate oxidative stress by reducing ROS levels. However, it was unclear if ROS levels would increase when photorespiration was lowered. Our goal was to examine the redox status in leaves when photorespiratory metabolism was restricted under low O (medium flushed with N gas) or by adding aminooxyacetic acid (AOA), a photorespiratory inhibitor. We examined the impact of low O and AOA in leaves of under dark, moderate, or high light. Downregulation of typical photorespiratory enzymes, including catalase (CAT), glycolate oxidase (GO), and phosphoglycolate phosphatase (PGLP) under low O or with AOA confirmed the lowering of photorespiratory metabolism. A marked increase in ROS levels (superoxide and HO) indicated the induction of oxidative stress. Thus, our results demonstrated for the first time that restricted photorespiratory conditions increased the extent of oxidative stress. We propose that photorespiration is essential to sustain normal ROS levels and optimize metabolism in cellular compartments of leaves.
The online version contains supplementary material available at 10.1007/s12298-023-01388-4.
光呼吸是植物新陈代谢的重要组成部分，在非生物胁迫条件下（如高光或干旱）会被上调。这种上调的信号之一是活性氧（ROS）的增加。光呼吸有望通过降低ROS水平来减轻氧化胁迫。然而，尚不清楚当光呼吸降低时ROS水平是否会升高。我们的目标是在低氧（用氮气冲洗培养基）或添加光呼吸抑制剂氨基氧乙酸（AOA）从而限制光呼吸代谢时，检测叶片中的氧化还原状态。我们研究了低氧和AOA在黑暗、中等光照或高光条件下对叶片的影响。在低氧或使用AOA的情况下，典型光呼吸酶（包括过氧化氢酶（CAT）、乙醇酸氧化酶（GO）和磷酸乙醇酸磷酸酶（PGLP））的下调证实了光呼吸代谢的降低。ROS水平（超氧化物和过氧化氢）的显著增加表明氧化胁迫的诱导。因此，我们的结果首次证明，受限的光呼吸条件会增加氧化胁迫的程度。我们提出，光呼吸对于维持正常的ROS水平和优化叶片细胞区室中的代谢至关重要。
在线版本包含可在10.1007/s12298-023-01388-4获取的补充材料。
