超表达谷子DREB类转录因子SiDREB2A能增强植物

李丛 于静娟

摘 要：DREB类（脱水响应元件结合蛋白类）转录因子通过结合DRE/CRT元件来调节胁迫响应相关基因的表达。过表达DREB类转录因子能增强转基因植物的胁迫耐受性。谷子脱水响应元件结合蛋白2A（SiDREB2A）是一个新克隆得到的DREB类转录因子。SiDREB2A的功能研究通过分析过表达转基因植株的表型来进行。利用实时定量PCR的方法来检测SiDREB2A的靶基因的表达情况。EMSA实验及酵母单杂交实验表明ABA响应元件结合蛋白（AREB）的转录因子可能参与调控SiDREB2A。SiDREB2A的表达量受干旱、高盐、ABA胁迫以及低温胁迫诱导升高。过表达SiDREB2A不经能显著的增强植物的抗逆能力，同时在转基因拟南芥和谷子中能激活下游靶基因的表达。SiDREB2A的启动子区含两个ABRE核心元件，且克隆得到的两个AREB类转录因子，SiAREB1和SiAREB2，能结合SiDREB2A启动子区的两个ABRE核心元件。以上结果表明SiDREB2A参与到不同的信号通路中，包括了非生物胁迫响应的ABA-依赖和ABA-不依赖的途径，并且在植物胁迫响应过程中具有重要作用。

关键词：非生物胁迫 谷子 SiDREB SiAREB 转录因子

Abstract：The DREB （dehydration responsive element binding）-type transcription factors （TFs） regulate the expression of stress inducible genes by binding the DRE/CRT cis-element in the promoter regions. Overexpression of DREB-type TFs enhances abiotic stress tolerance in transgenic plants. Setaria italica dehydration responsive element binding protein 2A （SiDREB2A） is a newly cloned DREB-type TF.Over-expressing transgenic plants were used to analyze the function of SiDREB2A. The target genes of SiDREB2A were examined by quantitative real-time PCR （qRT-PCR）. An electrophoretic mobility shift assay （EMSA） and yeast one-hybrid assay demonstrated that the ABA-responsive element binding （AREB） -type proteins were involved in the regulation of SiDREB2A.The transcript level of SiDREB2A increased under drought， high salt， abscisic acid （ABA）， and low temperature treatments. Overexpression of SiDREB2A not only resulted in significant abiotic stress tolerance but also in the activation of the target genes in transgenic Arabidopsis and foxtail millet. Two ABRE core elements exist in the promoter region of SiDREB2A and two cloned AREB-type TFs， SiAREB1 and SiAREB2， bind to the ABRE core element in SiDREB2As promoter region. These results reveal that SiDREB2A is involved in different signal pathways， ABA-dependent and ABA-independent， and plays a critical role in the plantsabiotic stress response.

Key Words：Abiotic stress；Foxtail millet；SiDREB；SiAREB；Transcription facto

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