Brassinosteroids promote photosynthesis and growth by enhancing activation of Rubisco and expression of photosynthetic genes in Cucumis sativus
Brassinosteroids promote photosynthesis and growth by enhancing activation of Rubisco and expression of photosynthetic genes in Cucumis sativus
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油菜素类固醇通过增强黄瓜中 Rubisco 的激活和光合基因的表达来促进光合作用和生长
DOI：
10.1007/s00425-009-1016-1
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发表时间：
2009-11-01
期刊：
影响因子：
4.3
通讯作者：
Yu, Jing-Quan
中科院分区：
文献类型：
--
作者：
Xia, Xiao-Jian;Huang, Li-Feng;Yu, Jing-Quan
植物甾醇类化合物（BRs）是一类新的促进植物生长和提高产量的植物生长物质。我们在这项研究中表明，24-表油菜素（EBR），一种活性BR处理后，黄瓜（黄瓜）植株的生长改善与增加的CO（2）同化和PSII（Phi（PSII））的量子产量有关。BR生物合成的特异性抑制剂Brz处理降低了植物生长，同时降低了CO（2）同化和Phi（PSII）。因此，BR的促生长活性可以至少部分地归因于增强的植物光合作用。为了了解BRs如何增强光合作用，我们分析了EBR和Brz对一些光合参数及其影响因素的影响，包括核酮糖-1，5-二磷酸羧化酶/加氧酶（Rubisco）的含量和活性。北方和Western印迹分析表明，EBR上调rbcL、rbcS等光合基因的表达，而Brz下调rbcL、rbcS等光合基因的表达。此外，EBR的基础上增加的最大Rubisco羧化速率（V（c，最大）），总Rubisco活性，并在更大程度上，初始Rubisco活性的Rubisco的激活有积极的影响。基于免疫金标记实验的Rubisco活化酶（RCA）的积累模式表明RCA在BR调节的Rubisco活化状态中的作用。EBR处理后编码其他卡尔文循环基因的基因的表达增强也可能在RuBP再生（J（max））中起积极作用，从而增加Rubisco的最大羧化速率（V（c，max））。因此，BR通过正向调节包括Rubisco在内的多种光合酶的合成和激活来促进黄瓜的光合作用和生长。
Brassinosteroids (BRs) are a new group of plant growth substances that promote plant growth and productivity. We showed in this study that improved growth of cucumber (Cucumis sativus) plants after treatment with 24-epibrassinolide (EBR), an active BR, was associated with increased CO(2) assimilation and quantum yield of PSII (Phi(PSII)). Treatment of brassinazole (Brz), a specific inhibitor for BR biosynthesis, reduced plant growth and at the same time decreased CO(2) assimilation and Phi(PSII). Thus, the growth-promoting activity of BRs can be, at least partly, attributed to enhanced plant photosynthesis. To understand how BRs enhance photosynthesis, we have analyzed the effects of EBR and Brz on a number of photosynthetic parameters and their affecting factors, including the contents and activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Northern and Western blotting demonstrated that EBR upregulated, while Brz downregulated, the expressions of rbcL, rbcS and other photosynthetic genes. In addition, EBR had a positive effect on the activation of Rubisco based on increased maximum Rubisco carboxylation rates (V (c,max)), total Rubisco activity and, to a greater extent, initial Rubisco activity. The accumulation patterns of Rubisco activase (RCA) based on immunogold-labeling experiments suggested a role of RCA in BR-regulated activation state of Rubisco. Enhanced expression of genes encoding other Calvin cycle genes after EBR treatment may also play a positive role in RuBP regeneration (J (max)), thereby increasing maximum carboxylation rate of Rubisco (V (c,max)). Thus, BRs promote photosynthesis and growth by positively regulating synthesis and activation of a variety of photosynthetic enzymes including Rubisco in cucumber.