Bioinformatics Analysis Of NAC Gene Family And Molecular Cloning,Expression Analysis And Phylogenetic Analysis Of The NAC Genes In Gossypium Arboreum L

Cotton (Gossypium) is one of the most important cash crops in the world and is the main raw material of the textile industry. Publishing the Cotton A genome and D genome sequence to build AD genome sequence map provided important information for cotton research for fiber quality improvement, stress tolerance and disease resistance. It laid a foundation for cultivating new species that have good fiber quality, stress tolerance or disease resistance.Transcription factors (TFs) are protein molecules that have a specific DNA binding activity of eukaryotic promoters, or protein molecule having known structural features of DNA-binding domain, whose main function is to activate or repress gene transcription reactions, and play a vital role in many important regulatory networks during development in the plant. About 5.9% of genes of the model plant Arabidopsis thaliana encode transcription factors. Transcription factors play an important role and are widespread in plants. It has become a research area of the post-genomic era. According to the DNA binding domain of different plants, transcription factor can be divided into many families; NAC (NAM/ATAF/CUC) transcription factors that are unique to plants are the new type of transcription factors that have multiple biological functions. TFs Play an important role in many physiological processes, such as plant growth and stress tolerance. Currently, the function of various plants NAC transcription factors has been further elaborated.Recently, research has also shown that NAC transcription factors involved in the secondary cell wall development of inflorescence stems in Arabidopsis epidermal. As the cotton fiber strength mainly depends on the deposition secondary cell wall, and the cotton fiber development mode and Arabidopsis cell development mode are similar, so as to improve cotton fiber quality research, many scholars have launched a study of NAC transcription factors, and have achieved some results.In this research we got 143 GaNAC protein sequences through bioinformatic analysis from G. arboretum protein database. The family members,chromosome location,conserved structure domains,phylogenetic relationship and genes structure of NACs were predicted and analyzed with bioinformatics method.Expression pattern studied of NAC genes in the tissues and organs of A, D and AD genomes. Phylogenetic analysis of NACs, a preliminary predict the potentially important function of NAC transcription factors. The results are as follows:1. Genome-wide identification of NAC genes in G. arboretum. We have identified 143 GaNAC genes through bioinformatic analysis, based on 29729 EST sequences and genome sequence of Garboretum, combined G. raimondii NAC transcription factor family studies.2. Phylogenetic analysis of plant NAC proteins. According to the phylogenetic analysis of NAC-domain proteins, G. arboretum NAC proteins were classified into 9 groups.3. Gene duplications have played crucial roles in the expansion of G. arboretum NAC gene family. Gene structure, gene chromosomal location and synteny analysis of GaNAC genes within the cotton genome demonstrated that gene duplications have likely played critical roles in the expansion and evolution of the NAC gene family in G. arboretum, resμ lting in diversification of GaNAC genes quantitatively, structurally and functionally.4. Tissue-specific expression profiles of cotton NAC genes, and their function prediction. Based on comparative analysis of NAC genes and among different cotton species and the tissue-specific expression profiles, we generally predicted the roles of NAC genes in G. arboretum.5. RT-PCR was used to clone the full length cDNAs of the three NAC genes, namely GaNAC20, GaNAC09 and GaNAC69. Preliminary bioinformatic analysis found GaNAC20 and GaNAC09 genes contain three exons and two inner introns, GaNAC69 contains four exons and three introns, as a good basis for further research.6. In order to further the function analysis, GaNAC20, GaNAC09 and GaNAC69 genes were connected with the PBI121 vector respectively and placed under the control of a 35S strong promoter to construct over-expression vector. The recombinants were obtained successfully, which lay a good foundation for subsequent function validation and application of the gene in cotton breeding.