Abstract: Small RNAs play important regulatory roles in response to environmental stress. However, miRNAs involve in the complex process of drought response and their regulatory mechanism remain to be further identified and explored. In this study, small RNA library of root, stem and leaf tissues from rice treated with drought was constructed and high throughput transcriptome was sequenced. The results showed that a total of 403 miRNAs were detected at genome-wide scale in all samples, including 352 known miRNAs and 51 new predicted miRNAs. There were 37, 35 and 56 miRNAs differentially expressed in roots, stems and leaves at 24 h after drought treatment, while 35, 62 and 65 miRNAs were differentially expressed in roots, stems and leaves at 96 h,  respectively. Moreover, 15 miRNAs were differentially expressed in each tissue at two time points after drought treatment, among which Osa-miR159f, Osa-miR164f, Osa-miR5082 and Osa-miR5493 were up-regulated during drought treatment. Thus, they might be key modulators in drought response. A total of 4 537 predicted target genes of miRNAs were obtained, and their functional annotation and GO/KEGG enrichment analysis were further carried out. Collectively, these results provided theoretical reference and data resource for the identification of new drought responsive miRNAs, and would contribute to the comprehensive mechanisms dissection of miRNAs involvement in drought tolerance regulation in plants.

Key words: rice, drought stress, small RNA, transcriptome, known miRNA, novel miRNA, target gene

摘要： small RNA在植物环境胁迫过程中起重要的调节作用。然而，参与干旱逆境响应复杂过程中的miRNAs及其调控机制仍有待于深入挖掘。对干旱胁迫处理不同时间的水稻根、茎和叶组织进行small RNA文库构建和转录组测序。所有样品共检测到403个miRNAs，其中已知miRNAs 352个，新预测miRNAs 51个。干旱处理后24 h的根、茎和叶中分别有37、35和56个差异表达miRNAs，而96 h的根、茎和叶中分别有35、62和65个差异表达miRNAs。15个miRNAs在干旱处理后两个时间点的根、茎和叶中均差异表达，其中，Osa-miR159f、Osa-miR164f、Osa-miR5082和Osa-miR5493受干旱诱导上调表达，是干旱响应中关键调控因子。预测到miRNAs靶基因4 537个，并进行了功能注释和富集分析。这些结果为鉴定干旱响应miRNAs并解析其参与抗旱的分子调控机理提供了理论和数据资源。

关键词: 水稻, 干旱胁迫, small RNA, 转录组, 已知miRNA, 新miRNA, 靶基因