Brassinosteroid-induced CO2 assimilation is associated with increased stability of redox-sensitive photosynthetic enzymes in the chloroplasts in cucumber plants
Brassinosteroid-induced CO2 assimilation is associated with increased stability of redox-sensitive photosynthetic enzymes in the chloroplasts in cucumber plants
复制标题
油菜素类固醇诱导的二氧化碳同化与黄瓜植物叶绿体中氧化还原敏感光合酶的稳定性增加有关
DOI：
10.1016/j.bbrc.2012.08.100
复制
发表时间：
2012-09-28
影响因子：
3.1
通讯作者：
Yu, Jing Quan
中科院分区：
文献类型：
--
作者：
Jiang, Yu Ping;Cheng, Fei;Yu, Jing Quan
类维生素B6（BRs）在植物生长发育、光合作用和抗逆性等方面具有重要作用，但其促进光合作用的机制目前尚不清楚。在这里，我们提供的证据表明，BR水平的增加增加PSII的量子产率，Rubisco活化酶（RCA）和果糖-1，6-二磷酸酶（FBPase）的活动，和CO2同化。BRs上调了叶绿体中抗坏血酸-谷胱甘肽循环相关基因的转录水平和酶的活性，导致叶绿体中还原型（GSH）与氧化型（GSSG）谷胱甘肽的比例增加。GSH/GSSG比率的增加保护RCA免受蛋白水解消化，并增加叶绿体中氧化还原敏感酶的稳定性。这些结果有力地表明，BR是能够调节谷胱甘肽的氧化还原状态的叶绿体通过激活抗坏血酸-谷胱甘肽循环。叶绿体巯基还原状态的增加促进了CO2同化，至少部分是通过翻译后修饰增强氧化还原敏感性光合酶的稳定性和活性。(C)2012 Elsevier Inc. All rights reserved.
Brassinosteroids (BRs) play important roles in plant growth, development, photosynthesis and stress tolerance; however, the mechanism underlying BR-enhanced photosynthesis is currently unclear. Here, we provide evidence that an increase in the BR level increased the quantum yield of PSII, activities of Rubisco activase (RCA) and fructose-1,6-bisphosphatase (FBPase), and CO2 assimilation. BRs upregulated the transcript levels of genes and activity of enzymes involved in the ascorbate-glutathione cycle in the chloroplasts, leading to an increased ratio of reduced (GSH) to oxidized (GSSG) glutathione in the chloroplasts. An increased GSH/GSSG ratio protected RCA from proteolytic digestion and increased the stability of redox-sensitive enzymes in the chloroplasts. These results strongly suggest that BRs are capable of regulating the glutathione redox state in the chloroplasts through the activation of the ascorbate-glutathione cycle. The resulting increase in the chloroplast thiol reduction state promotes CO2 assimilation, at least in part, by enhancing the stability and activity of redox-sensitive photosynthetic enzymes through post-translational modifications. (C) 2012 Elsevier Inc. All rights reserved.