亚洲棉(Gossypium arboreum L.)纤维次生壁加厚期NAC基因的鉴定与表达分析

Molecular Cloning and Expression Analysis of NAC Genes Specifically Expressed in the Fibers of Gossypium arboreum L.

基于亚洲棉29729条纤维相关EST(Expressed sequence tag)序列和亚洲棉基因组序列,并结合雷蒙德氏棉(G.raimondii)NAC(NAM/ATAF/CUC)转录因子家族的研究结果,利用生物信息学方法,鉴定出143个亚洲棉NAC转录因子家族基因;利用实时荧光定量PCR技术对30个NAC转录因子构建表达图谱,鉴定出7个基因在亚洲棉纤维细胞次生壁加厚期优势表达,进一步明确了它们在亚洲棉、雷蒙德氏棉和陆地棉中的表达模式差异。利用RT-PCR(Reverse transcription-polymerase chain reaction)技术克隆得到了3个NAC基因全长c DNA,将其命名为Ga NAC20、Ga NAC09和Ga NAC69,初步的生物信息学分析发现Ga NAC20和Ga NAC09基因均含有3个外显子和2个内含子,Ga NAC69含有4个外显子和3个内含子,为进一步研究奠定了良好基础。

A total of 29,729 fiber-related expressed sequence tags and the genome sequence of Gossypium arboreum L. were combined with NAC transcription factor family research findings from G. raimondii using bioinformatics to identify 143 NAC transcription factor genes from G. arboreum L. Quantitative real-time PCR was used to analyze the expression patterns of 30 of these genes, and the expressions of seven fiber advantage expressed genes were analyzed in G. hirsutum L., G. arboreum L., and G. raimondii. These seven genes showed different expression patterns in cotton plants with different genomes, suggesting that significant changes have taken place in these genes during the evolution of the cotton genome. The full-length cDNAs of three of these genes（designated GaNAC20, GaNAC09, and GaNAC69） were cloned successfully. Bioinformatic analysis showed that GaNAC20 and GaNAC09 are composed of three exons and two introns, while GaNAC69 has four exons and three introns. The encoded proteins have an NAM domain structure, which is typical of the NAC family of proteins. Multiple sequence align- ment and phylogenetic tree analysis predicted the function of these proteins, and laid the foundation for the study of NAC tran- scription factors in the evolution of the cotton genome.