四合木抗逆相关的转录因子TmAP2-1基因的克隆及功能分析

Cloning and Characterization of an AP2/EREBP Gene TmAP2-1 from Tetraena mongolica

AP2/EREBP家族的转录因子在调控植物生长发育和应答环境胁迫方面具有重要作用。利用同源克隆结合RACE(rapid-amplification of cDNA ends)技术,从四合木(Tetraena mongolica)中克隆了AP2/EREBP家族的基因,将其命名为TmAP2-1(GenBank登录号:JQ676996)。序列分析结果表明,该基因的开放阅读框长度为1452bp,编码483个氨基酸;比对结果显示TmAP2-1有2个AP2/ERF结构域,属于AP2/EREBP转录因子家族的AP2亚家族。亚细胞定位实验结果表明,TmAP2-1定位在细胞核中。该基因编码的蛋白在酵母中没有转录激活活性。利用Real-timePCR检测发现该基因在根、茎、叶等器官中均表达,且在叶中表达量最高。此外,TmAP2-1还受到NaCl、低温、PEG和ABA的强烈诱导,推测TmAP2-1可能参与四合木的逆境胁迫响应。在四合木愈伤组织中过表达该基因能够降低四合木愈伤组织中油脂的含量,同时提高可溶性糖的含量,暗示该基因可能通过影响糖代谢过程参与逆境胁迫响应。

AP2/EREBP transcription factors play important roles in plant morphology, development, and stress re- sponses. We cloned and characterized a putative AP2/ERF domain-containing gene from Tetraena mongo/ica by ho- mology-based cloning and rapid amplification of cDNA ends. This gene, designated TmAP2-1 （accession no. JQ676996）, encodes a protein of 483 amino acids with 2 copies of AP2 DNA binding domain. Subcellular localization analysis re- vealed that TmAP2-1 protein localized in the nucleus. TmAP2-1 protein has no transactivation activity in yeast. The ex- pression of TmAP2-1 is induced by cold, salt, polyethylene glycol and abscisic acid. TmAP2-1 is detected in roots, shoots and leaves of T. mongolica, with the highest expression in leaves. Overexpression of TmAP2-1, accumulation of more soluble sugars in T. mongolica callus, but in reduced lipid content. TmAP2-1 probably represents an AP2/EREBP gene that plays a regulatory role in tolerance of T. mongolica to abiotic stresses by affecting accumulation of soluble sugars.