超表達谷子DREB類轉錄因子SiDREB2A能增強植物

李叢 于靜娟

摘 要：DREB類（脫水響應元件結合蛋白類）轉錄因子通過結合DRE/CRT元件來調節脅迫響應相關基因的表達。過表達DREB類轉錄因子能增強轉基因植物的脅迫耐受性。谷子脫水響應元件結合蛋白2A（SiDREB2A）是一個新克隆得到的DREB類轉錄因子。SiDREB2A的功能研究通過分析過表達轉基因植株的表型來進行。利用實時定量PCR的方法來檢測SiDREB2A的靶基因的表達情況。EMSA實驗及酵母單雜交實驗表明ABA響應元件結合蛋白（AREB）的轉錄因子可能參與調控SiDREB2A。SiDREB2A的表達量受干旱、高鹽、ABA脅迫以及低溫脅迫誘導升高。過表達SiDREB2A不經能顯著的增強植物的抗逆能力，同時在轉基因擬南芥和谷子中能激活下游靶基因的表達。SiDREB2A的啟動子區含兩個ABRE核心元件，且克隆得到的兩個AREB類轉錄因子，SiAREB1和SiAREB2，能結合SiDREB2A啟動子區的兩個ABRE核心元件。以上結果表明SiDREB2A參與到不同的信號通路中，包括了非生物脅迫響應的ABA-依賴和ABA-不依賴的途徑，并且在植物脅迫響應過程中具有重要作用。

關鍵詞：非生物脅迫 谷子 SiDREB SiAREB 轉錄因子

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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