烟草NtKEA4基因的克隆、生物信息学及表达分析

Cloning, Bioinformatics and Expression Analysis of NtKEA4 Gene in Tobacco

K^+efflux antiporter (KEA)是一类钾离子反向转运蛋白,属于一价阳离子/质子反向转运体超家族,对植物细胞钾离子的积累和平衡具有重要作用。从烟草品种K326中利用同源克隆的方法获得一个钾离子反向转运蛋白基因,序列分析表明该基因全长1 749 bp,编码一个由582个氨基酸残基组成的酸性疏水蛋白。生物信息学分析预测该蛋白分子量为62.1 kD,理论等电点为5.50,含有11个跨膜区。同源性分析结果显示,该基因编码蛋白与美花烟草(Nicotiana sylvestris)钾离子转运体KEA4、辣椒(Capsicum baccatum)钾离子转运体KEA4等具有较高的同源性,所以将该基因命名为NtKEA4。表达模式分析表明,NtKEA4基因在组织中均有表达,但主要在烟草茎中表达,其表达受低钾、高盐、脱落酸(ABA)、低温等非生物胁迫条件的诱导。

K^+efflux antiporter(KEA) belong to monovalent cation/proton antiporters superfamily and it was im portant for plants to accumulate and balance potassium ion. We obtained a gene of K^+efflux antiporters from tobacco that variety ’K326’ by homologous cloning, sequence analysis showed that the gene contained 1 749 bp and encoded a stable acidic hydrophobic protein which consisted of 582 amino acids. Bioinformatics analysis suggested that the protein molecular weight was 62.1 kD, the theoretical isoelectric point was 5.50, consisting 11 trans membrane domains. Homology analysis suggested that the protein had a high homology with the K^+efflux an tiporter 4 of both Nicotiana sylvestris and Capsicum baccatum, so it was named as NtKEA4. Expression analysis showed that the gene expressed in roots, stems, leaves and flowers, but the highest expression level was observed in the stems, in addition, the gene expression were induced by abiotic stress such as low-potassium, high-salinity,ABA, low-temperature and so on.