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真核翻译起始因子eIF2α在真核生物蛋白合成中起到了重要的调节作用。本研究采用PCR方法克隆了栽培烟草(Nicotiana tabacum)K326的NteIF2α的ORF序列,并用RT-qPCR对该基因在烟草不同组织以及胁迫下的表达进行了分析。结果表明,栽培烟草K326中包含了NteIF2α-1(GenBank登录号KR184725)和NteIF2α-2(GenBank登录号KR184726)两个拷贝,核苷酸序列相似性为98.3%,氨基酸序列相似性为99.7%。氨基酸序列包含了典型的eIF2α功能域、保守的磷酸化调节位点和eIF2B作用位点。进化分析表明,NteIF2α-1和NteIF2α-2可能分别来自2个二倍体亲本林烟草(N.sylvestris)和绒毛状烟草(N.tomentosiformis),且与茄科进化关系更近。磷酸化位点分析表明,NteIF2α蛋白的56位丝氨酸是蛋白激酶潜在的磷酸化位点,可能参与蛋白合成的调节。此外,NteIF2α在烟草K326不同组织中的表达结果显示,NteIF2α-1和NteIF2α-2在不同组织器官中都有表达,且2种类型的NteIF2α呈现的表达模式不同,其中NteIF2α-2的表达量较高,这表明不同器官中eIF2α家族成员间的优势程度不同。水杨酸(SA)和茉莉酸甲酯(MeJA)可以诱导NteIF2α的表达,表明NteIF2α参与了植物对食草昆虫的应答过程。
Eukaryotic translation initiation factor eIF2α plays an important regulatory role in eukaryotic protein synthesis. In this study, the ORF of NteIF2α of Nicotiana tabacum K326 was cloned by PCR and analyzed by RT-qPCR in different tissues and under stress of tobacco. The results showed that two copies of NteIF2α-1 (GenBank accession number KR184725) and NteIF2α-2 (GenBank accession number KR184726) were contained in the cultivated tobacco K326, the nucleotide sequence similarity was 98.3% and the amino acid sequence similarity was 99.7%. The amino acid sequence contains a typical eIF2α domain, a conserved phosphorylation site and an eIF2B site. Phylogenetic analysis showed that NteIF2α-1 and NteIF2α-2 may originate from two diploid parents, N. sylvestris and N. tomentosiformis respectively, and they are more closely related to Solanaceae. Phosphorylation site analysis showed that the 56th serine of NteIF2α protein is a potential phosphorylation site of protein kinase and may be involved in the regulation of protein synthesis. In addition, NteIF2α expression in different tissues of tobacco K326 showed that NteIF2α-1 and NteIF2α-2 were expressed in different tissues and organs, and the expression patterns of the two types of NteIF2α were different. The expression level of NteIF2α-2 was higher than that of NteIF2α-2 High, indicating that the degree of advantage among the members of the eIF2α family in different organs is different. Salicylic acid (SA) and methyl jasmonate (MeJA) induced NteIF2α expression, indicating that NteIF2α is involved in plant response to herbivore insects.