Cellular glutathione redox homeostasis plays an important role in the brassinosteroid-induced increase in CO2 assimilation in Cucumis sativus
Cellular glutathione redox homeostasis plays an important role in the brassinosteroid-induced increase in CO2 assimilation in Cucumis sativus
复制标题
细胞谷胱甘肽氧化还原稳态在油菜素类固醇诱导的黄瓜 CO2 同化增加中发挥重要作用
DOI：
10.1111/j.1469-8137.2012.04111.x
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发表时间：
2012-06-01
期刊：
影响因子：
9.4
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
类甾醇（BRs）在植物生长、抗逆性和生产力方面起着重要作用。在这里，参与BR的调节CO2同化和细胞氧化还原稳态进行了研究。采用组织化学、细胞化学和分光光度法测定H2 O2、谷胱甘肽和光合相关酶的活性，采用Western blot和免疫金标记法测定Rubisco活化酶（RCA）活性，研究了BR对黄瓜CO2同化的影响。外源BR增加质外体H2 O2的积累，还原型氧化型谷胱甘肽（GSH：GSSG）和CO2同化的比例，而BR生物合成抑制剂有相反的效果。BR诱导的CO2同化减少H2 O2清除剂或抑制H2 O2的产生，GSH的生物合成和NADPH生成戊糖磷酸途径。BR-，H2 O2-或GSH诱导的CO2同化与本森卡尔文循环中的酶的活性增加。免疫胶体金标记和蛋白质印迹法显示，BR增加RCA的含量，这种作用被氧化还原稳态抑制剂阻断。这些结果强烈表明，BR诱导的光合作用涉及H2 O2介导的GSH：GSSG比例的增加，这可能是积极调节碳固定的氧化还原敏感酶的合成和激活。
Brassinosteroids (BRs) play a vital role in plant growth, stress tolerance and productivity. Here, the involvement of BRs in the regulation of CO2 assimilation and cellular redox homeostasis was studied. The effects of BRs on CO2 assimilation were studied in cucumber (Cucumis sativus) through the analysis of the accumulation of H2O2 and glutathione and photosynthesis-related enzyme activities using histochemical and cytochemical detection or a spectrophotometric assay, and Rubisco activase (RCA) using western blot analysis and immunogold labeling. Exogenous BR increased apoplastic H2O2 accumulation, the ratio of reduced to oxidized glutathione (GSH:GSSG) and CO2 assimilation, whereas a BR biosynthetic inhibitor had the opposite effects. BR-induced CO2 assimilation was decreased by a H2O2 scavenger or inhibition of H2O2 generation, GSH biosynthesis and the NADPH-generating pentose phosphate pathway. BR-, H2O2- or GSH-induced CO2 assimilation was associated with increased activity of enzymes in the BensonCalvin cycle. Immunogold labeling and western blotting showed that BR increased the content of RCA and this effect was blocked by inhibitors of redox homeostasis. These results strongly suggest that BR-induced photosynthesis involves an H2O2-mediated increase in the GSH:GSSG ratio, which may positively regulate the synthesis and activation of redox-sensitive enzymes in carbon fixation.