日本结缕草‘胶东青’DREB2.2基因克隆及表达模式研究

Cloning and Expression Profile of DREB2.2 Gene from Zoysia japonica var. pallida cv Jiaodong

DREB(dehydration responsive element binding protein)是植物中普遍存在的一类重要转录因子,参与植物逆境响应和生长发育过程。以日本结缕草‘胶东青’为材料,克隆获得了DREB2.2基因的编码区序列,分析了该基因的生物信息学特征,通过半定量PCR技术检测其逆境表达模式。测序结果表明,‘胶东青’DREB2.2基因存在长、短两个转录本。长转录本DREB2.2-L编码区长1 067 bp,多含一个长50 bp的序列,阅读框提前终止,仅推测编码65个氨基酸。短转录本DREB2.2-S编码区长1 017 bp,推测编码338个氨基酸,蛋白质分子量37.3 KD,等电点p I为4.86,含有一个保守的AP2结构域和核定位序列,属于DREB亚家族A-2组成员。半定量PCR结果显示,DREB2.2-S和DREB2.2-L在正常生长条件下有表达,低温胁迫时表达量上调,胁迫2 h时最高,干旱胁迫2 h和24 h时轻度上调表达,高盐胁迫下表达量无显著变化。在相同条件下,DREB2.2-L的表达量均略高于DREB2.2-S。

DREB（dehydration responsive element binding protein）is a type of transcription factor commonly existing in higher plants, and involves in abiotic stress response and the process of growth and development. In this study, using Zoysia japonica var. pallida cv Jiaodong as material, the coding sequence of gene DREB2.2 was cloned, then the bioinformatics were analyzed, and the expression profile of the gene in the stress environment was detected by semi-quantitative PCR technique. Sequencing analysis indicated that DREB2.2 had 2 transcripts of long and short. The long transcript, DREB2.2-L, was 1 067 bp in length, with a premature ORF because of a 50 bp insertion sequence, and putatively encoding 65 amino acids. The short one, DREB2.2-S, was 1 017 bp in length, encoding 338 amino acids;the putative protein was 37.3 k D, p I was 4.86, and it belonged to the A-2 group of DREB subfamily, containing an AP2 conservative structure domain and nuclear localization sequence. The results of semi-quantitative PCR showed that both DREB2.2-S and DREB2.2-L were expressed in normal condition, the expressions were up-regulated under low temperature stress with the highest level at 2 h exposure, and were slightly up-regulated during the 2 h and 24 h of drought stress, but showed no response to high salt stress. In both normal and stress conditions, the m RNA amount of DREB2.2-L was slightly higher than that of DREB2.2-S.