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DNA甲基化是一种重要的遗传修饰现象,植物中DNA甲基化主要是通过RNA介导的甲基化路径(RNA direct DNA methylation,Rd DM)而建立。其中ARGONAUTE 4(AGO4)和ARGONAUTE 6(AGO6)基因是该路径中重要的功能基因,它们能够结合24 nt的si RNA,目前烟草(Nicotiana tabacum L)中尚无这2个基因的报道。本文根据拟南芥(Arabidopsis thaliana)At AGO4及At AGO6的蛋白序列,通过同源比对烟草基因组数据库鉴定出烟草7个Nt AGO4及2个Nt AGO6候选基因。根据烟草基因组测序和转录组测序数据,预测了烟草Nt AGO4及Nt AGO6基因结构,结果表明候选基因具有相似的基因结构,均具有PIWI保守结构域。采用MEGA 6.0软件构建进化树,发现栽培烟草具有Nt AGO4及Nt AGO6候选基因。目前关于烟草基因信息的研究比较少,本研究丰富了对烟草AGO4及AGO6基因的认识。
DNA methylation is an important genetic modification phenomenon. DNA methylation in plants is mainly established by RNA direct DNA methylation (Rd DM). Among them, ARGONAUTE 4 (AGO4) and ARGONAUTE 6 (AGO6) genes are important functional genes in this pathway. They can bind to 24 nt of si RNA. There are no reports of these two genes in tobacco (Nicotiana tabacum L). In this study, we identified seven Nt AGO4 and two Nt AGO6 candidate genes in tobacco by homologous alignment of the tobacco genome database based on the protein sequences of At AGO4 and At AGO6 in Arabidopsis thaliana. Tobacco Nt AGO4 and Nt AGO6 gene structures were predicted based on the tobacco genome sequencing and transcriptome sequencing data. The results showed that the candidate genes had similar gene structure and all had the PIWI conserved domain. Using MEGA 6.0 software to construct phylogenetic tree, it was found that cultivated tobacco has Nt AGO4 and Nt AGO6 candidate genes. At present, there are few researches on tobacco genetic information. This study enriches the understanding of AGO4 and AGO6 genes in tobacco.