作为RNA诱导沉默复合体的核心元件,Argonaute(AGO)蛋白在植物生长发育过程中发挥着重要作用.以欧美杨和美洲黑杨不定根cDNA为模板,采用RT-PCR技术分离得到PeAG05和PdAG05基因的cDNA克隆,测序和序列分析结果表明2个目的cDNA片段均为2 809 bp,基因内部含有完整的开放阅读框,可编码907个氨基酸,预测蛋白质分子量分别为102.31 ku和102.34 ku,理论等电点(p1)分别为9.34和9.7.所推导的2个氨基酸序列之间仅有7个差异位点,含有3个保守的结构域,DUF1785、PAZ和Piwi结构域.它们与拟南芥AtAG05蛋白的相似性分别为64.8%和64.3%,故将其命名为PeAG05和PdAG05.系统进化分析发现,PeAG05和PdAG05,与拟南芥AtAG01,AtAG05和AtAG010蛋白同属一个进化分支.此外,采用实时定量PCR技术检测PeAG05基因在杨树硬枝插穗不定根发育过程中的表达模式,推测该基因参与不定根发育调控.%As the core component of RNA induced silencing complex ( RISC), Argonaute (AGO) proteins play an essential role in plant development and cellular metabolism. Our previous studies suggested that a predicted gene from Populus trichocarpa genome sequence, POPTR -0001s22120. 1, was preferentially expressed in adventitious root development of Populus cuttings. In this study, the target cDNA clones were isolated from the eDNA library prepared from adventitious roots of P.×euramericana and P. deltoides using RT-PCR technique, respectively. The two cDNAs were both 2 809 bp, and would encode for polypeptides of 907 amino acid residues with the molecular mass around 102.31 ku and 102.34 ku, the theoretical isoelectric point (pI) of 9.34 and 9.7, respectively. There is difference in seven distinct amino acid residues between the two deduced proteins which contain 3 conserved domains: DUF1785, PAZ and Piwi, and share 64.8％ and 64.3％ identify with AtAGO5 protein of Arabidopsis thaliana, respectively. They were, therefore,named as PeAGO5 and PdAGOS. Phylogenetic tree revealed that PeAGOS, PdAGOS, AtAGO1, AtAGO5 and AtAGO10 were assigned to the same clade. Quantitative real-time PCR analysis showed that PeAGO5 was differentially expressed during adventitious root development in hardwood cuttings of the poplars, indicating that PeAGO5 would be involved in adventitious root development.
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