中文摘要：

目的利用生物信息学手段预测黄芪Astragalus membranaceus的miRNA及其靶基因，应用定量PCR分析其干旱胁迫表达模式，为黄芪miRNA研究奠定基础。方法下载公共核酸数据库中的黄芪高通量测序序列，使用Trinity软件拼接获得转录本数据。利用生物信息学预测方法进行黄芪miRNA及其靶基因的预测，并对靶基因进行功能分类分析。利用茎环引物荧光定量PCR方法验证miRNA的存在，并分析miRNA在干旱胁迫下的表达模式。结果序列拼接获得88263条黄芪转录组数据。使用这些数据预测到分属于17个家族的17个miRNA序列以及相应的茎环结构前体。这些miRNA靶向的145个基因主要参与基因转录调控、物质代谢、信号转导、胁迫应答和蛋白翻译后修饰等生物学过程。随机选取8个miRNA进行茎环引物荧光定量PCR验证，其干旱逆境表达模式分析表明miR2118和miRl66可能参与了黄芪的干旱胁迫应答。结论预测的黄芪miRNA、靶基因以及干旱应答miRNA，为理解miRNA在黄芪中的生物学功能提供了重要数据。

英文摘要：

Objective To provide a good start for the study of miRNA in Astragalus membranaceus, the miRNAs and their targets were predicted using bioinformatics approach, then the drought-induced expression pattern was analyzed using quantitative RT-PCR. Methods The deep sequencing data downloaded from public database were assembled using Trinity to establish the transcriptome database. Bioinformatics method was employed to predict miRNAs and their targets, functional classification analyses of targets were conducted. Stem-loop fluorescence quantitative PCR method was used to validate miRNAs, and the drought-induced expression patterns of miRNA were also determined. Results A transcriptome database with 88 263 sequences was obtained. Based on the transcriptomic sequences, 17 miRNA, classified into 17 families, generated from 17 stem-loop precursors, were identified. A total of 145 genes were predicted to be regulated by these miRNAs, and these genes were involved into diversified biological processes including gene transcription regulation, substance metabolism, signal transduction, stress response, and post translational modification of protein. Eight miRNAs were randomly selected for expression analysis and the results indicated that miR2118 and miR166 might be involved in drought stress response. Conclusion The miRNAs, the corresponding targets and the drought response miRNAs identified in this study will provide a solid basis for understanding the biological functions of miRNAs in A. membranaceus.