State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, PR China.
BMC Genomics. 2011 Jul 15;12:367. doi: 10.1186/1471-2164-12-367.
MicroRNAs (miRNAs) are small, endogenous RNAs that play important regulatory roles in development and stress response in plants by negatively affecting gene expression post-transcriptionally. Identification of miRNAs at the global genome-level by high-throughout sequencing is essential to functionally characterize miRNAs in plants. Drought is one of the common environmental stresses limiting plant growth and development. To understand the role of miRNAs in response of plants to drought stress, drought-responsive miRNAs were identified by high-throughput sequencing in a legume model plant, Medicago truncatula.
Two hundreds eighty three and 293 known miRNAs were identified from the control and drought stress libraries, respectively. In addition, 238 potential candidate miRNAs were identified, and among them 14 new miRNAs and 15 new members of known miRNA families whose complementary miRNA*s were also detected. Both high-throughput sequencing and RT-qPCR confirmed that 22 members of 4 miRNA families were up-regulated and 10 members of 6 miRNA families were down-regulated in response to drought stress. Among the 29 new miRNAs/new members of known miRNA families, 8 miRNAs were responsive to drought stress with both 4 miRNAs being up- and down-regulated, respectively. The known and predicted targets of the drought-responsive miRNAs were found to be involved in diverse cellular processes in plants, including development, transcription, protein degradation, detoxification, nutrient status and cross adaptation.
We identified 32 known members of 10 miRNA families and 8 new miRNAs/new members of known miRNA families that were responsive to drought stress by high-throughput sequencing of small RNAs from M. truncatula. These findings are of importance for our understanding of the roles played by miRNAs in response of plants to abiotic stress in general and drought stress in particular.
microRNAs (miRNAs) 是内源性小分子 RNA，通过负调控基因的转录后表达，在植物的发育和应激反应中发挥重要的调控作用。高通量测序技术在全基因组水平上鉴定 miRNAs 对于植物中 miRNAs 的功能特征分析至关重要。干旱是限制植物生长和发育的常见环境胁迫之一。为了了解 miRNAs 在植物应对干旱胁迫中的作用，我们通过高通量测序鉴定了豆科模式植物苜蓿中的干旱响应 miRNAs。
从对照和干旱胁迫文库中分别鉴定出 283 个和 293 个已知 miRNAs。此外，还鉴定出 238 个潜在的候选 miRNAs，其中包括 14 个新的 miRNAs 和 15 个已知 miRNA 家族的新成员，其互补 miRNA*也被检测到。高通量测序和 RT-qPCR 均证实，在响应干旱胁迫时，有 4 个 miRNA 家族的 22 个成员上调，6 个 miRNA 家族的 10 个成员下调。在 29 个新的 miRNAs/已知 miRNA 家族的新成员中，有 8 个 miRNAs 对干旱胁迫有响应，其中 4 个 miRNAs 分别上调和下调。干旱响应 miRNAs 的已知和预测靶标被发现参与植物的多种细胞过程，包括发育、转录、蛋白质降解、解毒、营养状态和交叉适应。
通过对苜蓿中小 RNA 的高通量测序，我们鉴定了 32 个已知的 miRNA 家族成员和 10 个 miRNA 家族的新成员，以及 8 个新的 miRNAs/已知 miRNA 家族的新成员，它们对干旱胁迫有响应。这些发现对于我们理解 miRNAs 在植物应对非生物胁迫特别是干旱胁迫中的作用具有重要意义。
