日本结缕草转录因子基因ZjDREB1.4的功能特征分析

Characteristics of a Transcription Factor Gene ZjDREB1.4 from Zoysia japonica

DREB1(dehydration-responsive element binding protein1)是植物中广泛存在的转录因子,在应答非生物胁迫中起重要作用。该研究根据转录组测序数据,从暖季型植物日本结缕草‘Meyer’( Zoysia japonica Steud.)中克隆得到1个DREB1类转录因子基因,命名为ZjDREB 1.4。结果表明:(1)该基因推测编码226个氨基酸,含有一个AP2结构域,其上下游具有DREB1组的典型特征序列。(2)半定量RT-PCR检测显示,在日本结缕草叶组织中, ZjDREB 1.4基因在4 ℃低温、高盐和干旱胁迫下均上调表达,其中受低温诱导上调最显著。(3)亚细胞定位分析显示,ZjDREB1.4-GFP融合蛋白主要定位在细胞核中。(4)酵母单杂交结果显示,ZjDREB1.4蛋白具有强的转录激活功能,但与以ACCGAC为核心序列的DRE元件结合功能较弱。(5)与野生型拟南芥相比,超表达 ZjDREB 1.4的拟南芥植株的营养生长无明显改变,仅抽薹时间推迟3~8 d,但是对高温和冷冻低温胁迫的耐受能力明显增强。 ZjDREB 1.4基因具有抗逆功能,对植株生长发育的负效应又小,其在植物育种中的应用潜力值得进一步探究。

DREB1 (dehydration-responsive element binding protein 1) belongs to a subfamily of transcription factors found in plants that plays a key role during the response to abiotic stresses. On the basis of transcriptome sequencing data, we report a DREB 1 gene, designated ZjDREB 1.4 in this study, that was isolated from zoysiagrass ( Zoysia japonica Steud.), a popular warm-season turfgrass.(1) The ZjDREB 1.4 gene encodes a protein that contains 226 amino acids and has an AP2 domain flanked by sequences characteristic of DREB1 proteins from other species.(2) The expression of ZjDREB 1.4 was significantly induced by 4℃-cold stress, moderately induced by high salt and slightly induced by drought stress.(3) The product of the fusion gene ZjDREB 1.4- GFP was primarily targeted to the nucleus.(4) Yeast one-hybrid assays indicated that ZjDREB1.4 showed strong transactivation activity but weak binding to the DRE in which ACCGAC was the core sequence.(5) Transgenic Arabidopsis plants overexpressing ZjDREB 1.4 showed similar growth to WT (wild type) with only a 3-8 day delay in bolting, but showed higher survival rates with high temperature or freezing temperature stress. Since ZjDREB 1.4 functions in stress tolerance with weak adverse effect on plant growth and development, the potential usage of it in plant breeding is worthy of further study.