【摘要】 碱性亮氨酸拉链(basic leucine zipper,b ZIP)是植物中广泛存在的一类转录因子,参与多种胁迫响应与生长发育过程。本研究从小麦(Triticum aestivum)中克隆到一个热胁迫诱导的b ZIP家族转录因子基因Tab ZIP28(Gen Bank登录号:KT753298.1),ORF长度为1 713 bp,编码570个氨基酸。生物信息学分析结果表明,Tab ZIP28与拟南芥b ZIP家族转录因子中B亚组的3个基因Atb ZIP17、Atb ZIP28和Atb ZIP49归为一类。氨基酸序列比对结果表明,该蛋白具有b ZIP和跨膜结构域(transmembrane domain,TMD)两个保守结构域以及规范的位点1蛋白酶(site 1 protease,S1P)剪切位点。对该基因起始密码子ATG上游1 699bp的序列进行顺式作用元件分析,发现该基因的启动子区域包含众多激素和逆境胁迫响应元件。通过q RT-PCR对该基因在逆境胁迫下的表达模式进行分析,结果表明,Tab ZIP28在热胁迫处理1 h即上调表达且达到最大值;用20%PEG 6000模拟干旱环境处理小麦幼苗后,Tab ZIP28在处理6 h达到最大值,并在12 h时急剧下降;对5 mmol/L H2O2处理响应比较缓慢,在处理12 h才上调表达;该基因不受到二硫苏糖醇(dithiothreitol,DTT)处理的诱导表达。在拟南芥(Arabidopsis thaliana)中过量表达Tab ZIP28基因,转基因株系在高温胁迫后的成活率和种子发芽率较野生型明显提高,说明该基因可能对植物的耐热性有贡献,可以作为耐热性育种的候选基因。更多还原

【Abstract】 Basic leucine zipper(bZIP) transcription factor family widely distributes in plant and involves in multiple stress response and developmental stages. In this study,we cloned a heat induced transcription factor gene Tab ZIP28(Gen Bank accession No. KT753298.1) from wheat(Triticum aestivum),the length of ORF was 1 713 bp,encoding a protein of 570 amino acid residues. Sequence analysis indicated that Tab ZIP28 possessed a conserved b ZIP domain,a transmembrane domain(TMD) and a canonical site 1 protease(S1P)cleavage site. The promoter region of Tab ZIP28 contained several stress related cis- element. The expression patterns of Tab ZIP28 were analyzed by q RT-PCR under stress conditions. The results showed that Tab ZIP28 was induced by heat and peaked at 1 h; the transcript level of Tab ZIP28 was increased to the highest level by 20% PEG treatment for 6 h and reduced rapidly after 12 h; Tab ZIP28 was found to be slightly up-regulated by treatment of 5 mmol/L H2O2 for 12 h and Tab ZIP28 could not be induced by DTT treatment. To investigate the function of Tab ZIP28,we overexpressed Tab ZIP28 in Arabidopsis thaliana and assessed the thermotolerance of the transgenic lines. The results showed that the survival rate and germination rate of transgenic lines after heat stress were statistically higher than the wild type. This indicated that Tab ZIP28 could contribute to heat stress tolerance and could be used as a candidate gene for breeding of thermotolerant cultivars.更多还原