珠眉海棠(Malus zumi Mats)盐应答MzDREBb基因的克隆与功能研究

Cloning and characterization of salt-responding MzDREBb gene from Malus zumi Mats

通过microarray(微列阵芯片)分析,从珠眉海棠盐胁迫cDNA文库中分离得到盐诱导的MzDREBb基因全长cDNA序列,研究苹果属植物DREB转录因子在胁迫中的作用。结果表明:MzDREBb全长1 185bp,开放阅读框共714bp,5′-UTR和3′-UTR的长度分别是121和350bp;MzDREBb编码237个氨基酸,有一个AP2/ERF结构域;系统分类将MzDREBb归入DREB家族的A-5亚组;MzDREBb定位在细胞核中,具有转录激活活性;半定量RT-PCR表明MzDREBb基因受到盐诱导。超表达MzDREBb基因的拟南芥耐盐能力增强。以上结果表明MzDREBb基因在盐胁迫应答中起重要作用。

The DREBs are transcription factors which play central roles in abiotic stress response.Malus zumi,an apple rootstock,can survive 0.6% NaCl.The full-length cDNA sequence of MzDREBb gene was isolated from a cDNA library of Malus zumi by microarray analysis.The full-length cDNA of MzDREBb was 1 190 bp.Its open reading frame of 714 bp encoded a protein of 237 amino acids.The 5＇-UTR and the 3＇-UTR were 121 and 355 bp respectively.Base on multiple sequence alignment and phylogenetic characterization,MzDREBb was classified into A-5 subgroup of the DREB subfamily.The MzDREBb was localized in the nucleus,which exhibited transactivation activity in yeast two-hybrid system.MzDREBb was induced by either stress of high salinity or low temperature,but not by abscisic acid（ABA）.Transgenic Arabidopsis over-expressing MzDREBb could enhance salt tolerance.In conclusion,MzDREBb is involved in salt response through an ABA-independent pathway in Malus zumi.