李叢 于靜娟

摘 要：DREB類（脫水響應(yīng)元件結(jié)合蛋白類）轉(zhuǎn)錄因子通過結(jié)合DRE/CRT元件來調(diào)節(jié)脅迫響應(yīng)相關(guān)基因的表達(dá)。過表達(dá)DREB類轉(zhuǎn)錄因子能增強(qiáng)轉(zhuǎn)基因植物的脅迫耐受性。谷子脫水響應(yīng)元件結(jié)合蛋白2A（SiDREB2A）是一個(gè)新克隆得到的DREB類轉(zhuǎn)錄因子。SiDREB2A的功能研究通過分析過表達(dá)轉(zhuǎn)基因植株的表型來進(jìn)行。利用實(shí)時(shí)定量PCR的方法來檢測(cè)SiDREB2A的靶基因的表達(dá)情況。EMSA實(shí)驗(yàn)及酵母單雜交實(shí)驗(yàn)表明ABA響應(yīng)元件結(jié)合蛋白（AREB）的轉(zhuǎn)錄因子可能參與調(diào)控SiDREB2A。SiDREB2A的表達(dá)量受干旱、高鹽、ABA脅迫以及低溫脅迫誘導(dǎo)升高。過表達(dá)SiDREB2A不經(jīng)能顯著的增強(qiáng)植物的抗逆能力，同時(shí)在轉(zhuǎn)基因擬南芥和谷子中能激活下游靶基因的表達(dá)。SiDREB2A的啟動(dòng)子區(qū)含兩個(gè)ABRE核心元件，且克隆得到的兩個(gè)AREB類轉(zhuǎn)錄因子，SiAREB1和SiAREB2，能結(jié)合SiDREB2A啟動(dòng)子區(qū)的兩個(gè)ABRE核心元件。以上結(jié)果表明SiDREB2A參與到不同的信號(hào)通路中，包括了非生物脅迫響應(yīng)的ABA-依賴和ABA-不依賴的途徑，并且在植物脅迫響應(yīng)過程中具有重要作用。

關(guān)鍵詞：非生物脅迫 谷子 SiDREB SiAREB 轉(zhuǎn)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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