番杏TtASR基因的克隆及其抗逆功能分析

ASR(ABA, Stress and Ripening)蛋白是植物中特有的亲水性小分子蛋白,在植物细胞失水条件下对细胞器起保护性作用。本研究在构建番杏[Tetragonia tetragonioides (Pall.) Kuntze]全长cDNA文库中通过随机克隆测序分析基础上,获得了一个编码番杏ASR蛋白的全长cDNA序列,命名为TtASR(GenBank登录号:MH454101)。TtASR的cDNA全长序列包含一个为723 bp完整开放阅读框,编码蛋白TtASR含有240个氨基酸,等电点为5.26,分子量为25.29 ku。对TtASR与其他植物中同源蛋白的进化分析表明,与辽宁碱蓬SlASR和海蓬子SbASR-1亲缘关系较近。将TtASR的cDNA阅读框插入到原核表达载体pGEX6p-1中,通过转化大肠杆菌进行原核表达分析。结果表明,重组大肠杆菌菌株能表现出良好地抗逆性,特别是对NaCl、高渗透压和氧化胁迫的抗逆性增强。

Cloning and Functional Characterization for Abiotic Stress Tolerance of TtASR Gene from Tetragonia tetragonioides

ABA, stress and ripening (ASR) protein belongs to a plant-specific small family of proteins with low molecular weight and high hydrophobicity, and is supposed to play protective roles in plant cells under abiotic stresses. An ASR gene, designated as TtASR (GenBank accession no.: MH454101), was isolated from a cDNA library prepared from Tetragonia tetragonioides (Pall.) Kuntze and both the nucleotide and the deduced protein sequences were analyzed. The full length cDNA of TtASR contained a 723 bp long open reading frame, which would encode a peptide of 240 amino acid residues with a molecular weight of 25.29 ku and an isoelectric point of 5.26. TtASR shared a high amino acid sequence homology with the ASRs from Suaeda liaotungensis (SlASR) and Salicornia brachiata (SbASR-1). The open reading frame of TtASR was inserted into the prokaryotic expression vector of pGEX 6p-1 and transformed into E. coli. The E. coli cells under the induction of IPTG showed higher tolerance to NaCl, osmotic stress and oxidative stress than control cells.