小兰屿蝴蝶兰(Phalaenopsis equestris)NAC转录因子家族的全基因组序列鉴定及其进化分析

Identification,characterization and evolution of NAC transcription factors in Phalaenopsis equestris

兰科植物具有多样的生物学特性和重要的商品特性。其中,小兰屿蝴蝶兰是第一个全基因测序的兰科植物,对其中重要基因家族的发掘是进行兰科植物基因组水平研究的重要环节。文章采用BLAST方法从小兰屿蝴蝶兰全基因组序列中筛选出NAC转录因子,并对这些转录因子进行进化分析、保守结构域和基因结构的分析。经过结构域确认,总共鉴定出86个含有典型的NAM结构域的NAC转录因子;其中,PEQU_23244和PEQU_40419两个基因的C-端各预测出1个跨膜区,属于MTFs(membrane-bound transcription factors)。多序列比对分析结果显示,其中16个基因的NAM结构域并不完整。将其余70个基因与拟南芥的NAC转录因子一起构建进化树,结果表明,这些基因可以分为group A和group B两大类,分别包含3个和12个亚家族。小兰屿蝴蝶兰group A的基因间蛋白序列和基因结构差异较大,而group B中的基因间则相对保守。对NAM亚家族基因的分析表明,该亚家族基因的NAM结构域高度保守,且与拟南芥CUC1、CUC2、CUC3高度同源。

Orchid species show variable biological characters and important commodity characteristics .Phalaenopsis equestris is the first species in Orchidaceae whose whole-genome sequencing has been finished .It＇s essential to mine important gene families in Phalaenopsis equestris for genomics research of orchidaceae .In this paper , NCBI blast search was adopted to identify NAC transcription factors in Phalaenopsis equestris, and then phylogenetic relation-ships, conserved domain and gene structure analysis of these genes were performed .After removing redundant and mismatch sequences , 86 genes in Phalaenopsis equestris were identified as PeNACs, all of which contained a typical NAM domain.Two of them （PEQU23244 and PEQU40419）, predicted to have a transmembrane motif in C-termi-nal sequence , belonged to MTFs （ membrane-bound transcription factors ） .Sixteen of all 86 PeNACs only contained parts of the consensus sequence for NAM domain .The rest 70 PeNACs were used to construct phylogenetic tree with AtNACs.According to phylogenetic analysis , all these genes could be divided into A and B two major groups , and each of them were further classified into 3 and 12 subfamilies.The gene and protein structure of PeNACs were more diverse in group A than in group B .Members of NAM subfamily in PeNACs were highly homologous with Arabidopsis CUC1, CUC2 and CUC3.