中文摘要：

W6基因是由普通小麦地方品种小白麦cDNA文库中克隆获得的ERF类转录因子,属于ERF IV家族。将W6基因构建在由组成型CaMV35S强启动子控制的双子叶转化载体pBI121上,通过农杆菌介导法将其转入烟草新华1号。利用RT-PCR技术分析W6基因的过量表达对下游抗性基因表达水平的影响,并测定高盐胁迫下转基因烟草的SOD酶活性和叶绿素含量。结果显示,所检测的转基因烟草阳性株中W6基因均有不同程度的表达,其耐盐性明显提高。W6基因的表达诱导并增强了含有GCC box的PR（pathogenesis-related）基因和含有DRE/CRT元件的COR/RD基因的表达。在高盐胁迫下,转基因烟草的SOD酶活性和叶绿素含量明显高于对照。W6基因既能诱导抗病相关的PR基因表达又能诱导与提高非生物胁迫能力的COR/RD基因表达,可能与生物胁迫和非生物胁迫相关,证实转录因子W6参与了耐盐胁迫相关基因的调节,W6基因的过表达提高了转基因烟草的耐盐性。

英文摘要：

Ethylene responsive factors （ERFs） are important plant-specific transcription factors. Some of them have been identified to interact with the ethylene-responsive GCC box and the dehydration responsive element （DRE）. They usually play very important regulatory roles in response to biotic and abiotic stresses in plants. In our study, an ERF gene W6 was isolated from wheat （Xiao baimai） cDNA library, which belongs to ERF IV subfamily. Full-length W6 cDNA encoded an ERF protein containing a conserved ERF DNA-binding motif, two putative nuclear localization sequences and a C-terminal acidic transcription activation domain. W6 expression in wheat can be induced by various treatments such as cold, drought, salt, ABA and fungal pathogens. We constructed transgenic vector （35S：：pBI121：：W6） containing CaMV 35S promoter and then obtained W6-overexpresed tobacco plants by Agrobacterium-mediated transformation in order to identify the function of W6. Under the treatment with 200 mmol L^-1 NaCl for 50 d, the transgenic plants grew well but the control plants nearly died. The root length of transgenic tobacco plants was between 1.40 cm and 3.93 cm, while that of the control only 0.20 cm. The root weight of transgenic tobacco plants was between 2.41 g and 7.79 g, while that of the control only 0.06 g. SOD activity and chlorophyll content in transgenic plants increased markedly compared to the control. All results the above showed that the overexpression of W6 improved tobacco＇s salt tolerance, and W6 may act as a connector among different signal transduction pathways. The overexpression of W6 activated the expression of GCC box-containing genes PR2, PR3, PR5, and DRE/CRT genes NtERDIOA and NtERDIOC under normal growth conditions, and the tolerance to salt stress was improved in transgenic tobacco plants, which suggested that W6 regulates osmotic tolerance by activation of downstream gene expression through interaction with the GCC box or DRE,