Effects of exogenous nitric oxide on antioxidation and DNA methylation of Dendrobium huoshanense grown under drought stress
Effects of exogenous nitric oxide on antioxidation and DNA methylation of Dendrobium huoshanense grown under drought stress
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DOI：
10.1007/s11240-011-0096-3
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发表时间：
2012-05-01
影响因子：
3
通讯作者：
Lin, Yi
中科院分区：
文献类型：
--
作者：
Fan, Honghong;Li, Tingchun;Lin, Yi
一氧化氮（NO）是植物体内重要的生物信使，参与了植物对非生物胁迫的反应。为了研究外源NO对霍山石斛管苗干旱胁迫的影响，选用10%聚乙二醇（PEG-6000）处理霍山石斛管苗，模拟干旱胁迫。施用硝普钠（SNP）后，测定其相对含水量（RWC）和抗氧化酶活性。结果表明，在50 μ mol L-1 SNP处理下，植株保持了较高的RWC水平和较低的丙二醛（MDA）含量。抗氧化酶活性明显增强。而SNP浓度越高（100 μ mol L-1），植株的干旱胁迫效应越强。为了进一步分析外源NO的响应机制，利用甲基化敏感扩增多态性（methyl- sensitive amplification polymorphism， MSAP）技术研究了DNA甲基化的变化。在霍山石斛幼苗中添加含有10% PEG-6000的50 μ mol L-1 SNP处理后，霍山石斛整体DNA甲基化水平降低。然而，甲基化位点的去甲基化率增加，占总甲基化位点的12.5%。这些结果表明，霍山石斛对NO引发的干旱胁迫的响应过程中有部分表达基因参与。
Nitric oxide (NO) is an important biological messenger in plants, which has been implicated in response to abiotic stress. To study the effects of exogenous NO on drought menace, the tube seedlings of Dendrobium huoshanense were selected and treated with 10% polyethylene glycol (PEG-6000) to simulate drought stress. After application of sodium nitroprusside (SNP), the relative water content (RWC) and antioxidant enzyme activities were determined. As a result, plant treated with 50 mu mol L-1 of SNP maintained high level of RWC and lower content of malondialdehyde (MDA). Furthermore, the antioxidant enzyme activities were obviously enhanced. However, the higher concentration of SNP (100 mu mol L-1) enhanced the effects of drought stress for plant. For further analysis of the response mechanism to exogenous NO, the methylation-sensitive amplified polymorphism (MSAP) technique was used to investigate the changes of DNA methylation. When the seedlings of Dendrobium huoshanense were treated with 50 mu mol L-1 SNP containing 10% PEG-6000, levels of global DNA methylation of Dendrobium huoshanense were decreased. Nevertheless, the demethylation rate of methylated sites increased, accounting for 12.5% of total methylation sites. These results implied that some expressed genes were involved in the response process to drought stress triggered by NO in Dendrobium huoshanense.