大豆ERF转录因子基因GmERF8的克隆与表达分析

ERF转录因子广泛存在于植物中并且参与植物应对生物及非生物胁迫的响应。本研究利用RT-PCR技术从大豆中克隆获得1个新的ERF转录因子基因Gm ERF8,开放阅读框全长627 bp,编码1个由208个氨基酸残基组成的分子量为23.43 k D的蛋白。蛋白结构预测发现,该蛋白含有1个典型的AP2/ERF结合域,2个预测的核定位信号和1个保守的EAR抑制元件。进化分析表明Gm ERF8蛋白与烟草Nt ERF3蛋白的同源性最高。实时荧光定量PCR表明,Gm ERF8在大豆的根和叶中表达量较高。ABA、高盐和低温处理均使Gm ERF8表达量下降;乙烯(ET)和干旱处理则使Gm ERF8的表达量先下降后升高。转录调节能力分析结果显示,Gm ERF8可以抑制报告基因的表达。上述实验结果表明,Gm ERF8可能作为转录抑制子参与大豆对环境胁迫的应答。     

大豆转录因子GmERF5的克隆、表达及功能分析

ERF转录因子是植物中特有的转录因子家族之一, 在植物响应生物和非生物胁迫过程中发挥重要的调控作用。通过对大豆(Glycine max)吉林32未成熟胚的表达谱分析, 利用RT-PCR技术从大豆中克隆了1个新的ERF转录因子GmERF5。GmERF5具有237个氨基酸残基, 分子量为26.09 kDa, 等电点为6.85, 其开放阅读框长714 bp。该转录因子蛋白与Gh-ERF2蛋白的同源性最高, 它们同属ERF亚家族的第IV亚类。实时荧光定量PCR分析表明, 该蛋白基因在大豆的根中表达量最高, 且受干旱、高盐、低温及乙烯、脱落酸和茉莉酸甲酯的诱导上调表达。亚细胞定位实验结果表明, GmERF5蛋白定位于细胞核中。转录激活能力分析结果显示, GmERF5可以激活报告基因的表达, 为转录激活子。综合以上结果, 认为GmERF5可能作为转录调控因子参与大豆生物和非生物胁迫的应答。     

Overexpression of soybean <Emphasis Type="Italic">GmERF9</Emphasis> enhances the tolerance to drought and cold in the transgenic tobacco

Ethylene response factors (ERFs) are widespread in plants, which are widely involved in plant response to biotic and abiotic stress. In this research, a soybean gene, GmERF9, was identified and the function was characterized. The results showed that GmERF9 contained a typical AP2/ERF binding domain and a putative nuclear localization signal sequence. The real-time fluorescence quantitative PCR (qPCR) revealed that the expression of GmERF9 could be induced by ethylene (ET), abscisic acid (ABA), drought, salt and cold stresses. GmERF9 protein could specifically bind to the GCC-box and activate the expression of the reporter gene in the yeast cells and tobacco leaves. Overexpression of GmERF9 enhanced the expression of pathogenesis-related (PR) genes, including PR1, PR2, Osmotin (PR5), and SAR8.2. Also, the overexpression of GmERF9 increased the accumulation of proline and soluble carbohydrate, and decreased the accumulation of malondialdehyde under drought and cold stresses in the transgenic tobacco compared to the wild type (WT) tobacco, which indicated that GmERF9 enhanced the tolerance to drought and cold stresses in the transgenic tobacco. In summary, the function of GmERF9 is involved in the response to environmental stresses for plants, which can be used as a candidate gene for genetic engineering of crops.