Abstract:

In this study, a full\|length cDNA sequence of DREB transcription factor gene, HhDREB2 (Genbank No.: EU872018), was isolated from Halimodendron halodendron. Voss by homology\|based cloning and RACE (rapid amplification of cDNA end) technology. Sequence analysis showed that the cDNA sequence is 873 bp without introns and has a maximum open reading frame from 108 to 626 bp, encoding 172 amino acid residues. Molecular weight of the gene encoding protein is 19.702 kDa, isoelectric point is 8.92. Phylogenetic tree and homologous sequence alignment analyses indicated that this protein contained a typical AP2/ERF conservative domain, and was most closely related to soybean GmDREB2, belonging to the A5 subgroups. Yeast one\|hybrid experiment demonstrated that HhDREB2 gene encodes a transcription activator. In addition, subcellular localization analysis of a construct with the transient expression vector of the HhDREB2 gene showed that the HhDREB2 protein was localized in the nucleus. The expression level of HhDREB2 gene was greatly induced by high salt, drought and low temperature through semi\|quantitative RT\|PCR, and had no significant change with GA3, NAA, ABA and 6BA treatments.

Key words: Halimodendron halodendron. Voss, DREB transcription factor, RACE technology, yeast one\, hybrid, semi\, quantitative RT\, PCR, subcellular localization

摘要：

利用同源克隆和RACE(rapid amplification of cDNA end)技术从豆科铃铛刺属灌木铃铛刺中分离了一个DREB类转录因子基因的全长cDNA序列，命名为HhDREB2（Genbank No.:EU872018）。序列分析表明，该基因全长为873 bp，在108~626 bp处为开放阅读框，无内含子，编码172个氨基酸残基，分子质量为19.702 kDa，等电点8.92。系统进化树和同源序列比对分析结果显示，该基因编码的蛋白含有一个典型的AP2/ERF保守结构域，并与大豆GmDREB1和GmDREB2的亲缘关系较近，属于A5亚组。通过酵母单杂交试验，发现HhDREB2基因编码的蛋白具有转录激活的功能。此外，在洋葱表皮细胞中进行该基因的瞬时表达，证实了HhDREB2蛋白定位于细胞核。半定量RT\|PCR检测发现，HhDREB2基因受干旱、高盐和低温的诱导表达，而对GA3、NAA、ABA和6BA的处理无明显的变化。

关键词: 铃铛刺；DREB转录因子；RACE技术；酵母单杂交；半定量RT\, PCR；亚细胞定位