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为了深入研究小麦中NAC家族转录因子基因,针对NAC基因家族成员,设计了覆盖其全长编码区的1对特异引物,从陕253小麦品种中克隆了2条大小分别为1 463、1549 bp的片段,命名为TaNAC2、TaNAC4(GenBank登录号为HQ872050-HQ872051)。序列分析表明,这2个序列包含典型NAC的完整编码序列,包括两个内含子,具有完整的开放阅读框;推导的氨基酸序列分别为383、405个,这2个基因在N-端均具有NAC基因的典型DNA结合结构域,即NAC结构域,且氨基酸序列在该结构域的A、B、C、D、E5个亚区高度保守,仅在C亚区出现一个氨基酸的差异L-M,而且在C-D区出现罕见的半胱氨酸变异,此发现对于小麦品质的研究非常重要。同时发现这2个NAC类转录因子都不含有核定位信号(NLS),但是有相关的转录调控功能区域。通过系统进化树分析,证实克隆序列属于NAC基因家族成员,并且发现的TaNAC4属于NAC转录因子家族的NAM亚组,TaNAC2属于NAC转录因子家族的CUC亚组。
In order to further study the NAC family transcription factor genes in wheat, a pair of specific primers covering the full-length coding region of NAC gene family members were designed. Two wheat genotypes with a size of 1 463 and 1549 bp The fragments were named TaNAC2 and TaNAC4 (GenBank Accession No. HQ872050-HQ872051). Sequence analysis showed that these two sequences contained the complete coding sequence of typical NAC, including two introns with a complete open reading frame. The deduced amino acid sequences were 383,405, respectively. These two genes were N-terminal The NAC domain, a typical DNA binding domain of NAC gene, is highly conserved in the A, B, C, D, and E subregions of the amino acid sequence of the NAC domain, and has an amino acid difference of only LM in the C subregion. In addition, a rare cysteine mutation appeared in the CD region. This finding is very important for the study of wheat quality. At the same time, it was found that none of the two NAC-type transcription factors contained nuclear localization signal (NLS), but there were related functional regions of transcriptional regulation. Phylogenetic tree analysis confirmed that the cloned sequences belong to the NAC gene family. TaNAC4 was found to belong to NAM subgroup of NAC transcription factor family, and TaNAC2 belongs to CUC subgroup of NAC transcription factor family.