南京农业大学揭示miRNA调控铅胁迫应答

摘要 : 南京农业大学柳李旺教授带领的研究团队在新研究中，从分子水平揭示萝卜在铅(Pb)胁迫萝卜在铅(Pb)胁迫下的调控网络和反应机制，研究结果也为植物应答Pb胁迫时miRNA介导的调控网络和分子机制提供了基本见解。相关文章发表于近期的《Plant Molecular Biology Reporter》杂志上。

萝卜是一种重要的根菜类蔬菜作物，其肉质直根为可食用部分。重金属胁迫对萝卜的种植和生产有重大影响。越来越多的证据显示，micrornA(miRNA)介导的基因调控在重金属胁迫应答中起着重要作用。不过，目前几乎没有信息是关于在铅毒性应答时植物miRNA的表达模式或调控作用的。

南京农业大学柳李旺教授带领的研究团队从分子水平上对萝卜在铅(Pb)胁迫下的调控网络和反应机制进行了研究，研究成果发表在7月刊的Plant molecular Biology Reporter上。

研究人员通过高通量测序和降解组分析(降解组测序项目由联川生物承担完成)，对Pb胁迫下的萝卜进行了全基因组水平的miRNA鉴定并探讨了miRNA调控的靶基因。实验从两个萝卜根文库中(一个是未经处理的萝卜根，另一个是Pb胁迫的萝卜根)共鉴定出74个已知的和173个潜在的新miRNAs。其中，25个已知的和9个新发现的miRNAs有显著差异表达，并鉴定为Pb应答miRNAs。降解组分析显示，1979对miRNA-mRNA靶向转录本很有可能被剪切。

GO分析表明，这些靶向转录本主要参与转录调控，防御反应和结合相关的功能。Pb应答miRNAs调控的靶基因主要参与胁迫相关信号的感知和传导，特定金属的吸收，以及体内平衡机制。另外，研究人员通过实时荧光定量PCR(qRT-PCR)技术，对20个Pb应答miRNAs和6个靶基因的表达模式进行了验证。

此研究结果表明，miRNA在Pb胁迫时，发生显著地差异表达，在Pb应答过程中起到调控作用。研究结果也为植物应答Pb胁迫时miRNA介导的调控网络和分子机制提供了基本见解。

原文摘要：

Identification of Radish (Raphanus sativus L.) miRNAs and Their Target Genes to Explore miRNA-Mediated Regulatory Networks in Lead (Pb) Stress Responses by High-Throughput Sequencing and Degradome Analysis

Yan Wang, Wei Liu, Hong Shen, Xianwen Zhu, Lulu Zhai, Liang Xu, Ronghua Wang, YIQin Gong,Cecilia Limera, Liwang Liu

Increasing evidence has revealed that microRNA (miRNA)-mediated gene regulation plays a significant role in response to heavy metal stresses. However, there is little information available about the expression patterns or roles of miRNAs under lead toxicity stress in plants. The radish is an important root vegetable crop with a fleshy taproot as the edible part. It was of vital importance to investigate the response mechanisms and explore the regulatory network at the molecular level under the heavy metal stresses in radish. In the present study, using high-throughput sequencing and degradome analysis, a genome-wide identification of radish miRNA and their targets under the exposure of Pb stress was conducted. A total of 74 known and 173 potential novel miRNAs were successfully identified from two radish root libraries of one untreated control (CK) and one Pb-stressed (Pb500). Of these, 25 known and nine novel miRNAs were significantly differentially expressed and identified as Pb-responsive miRNAs. Degradome analysis revealed that 1,979 miRNA-mRNA target transcripts could potentially be cleaved. Gene Ontology (GO) analysis revealed that these target transcripts were predominately involved in the regulation of transcription, defense responses, and binding related terms. The identified target genes for Pb-responsive miRNAs were mainly involved in stress-related signal sensing and transduction, specific metal uptake and homeostasis mechanisms. Additionally, the expression patterns of 20 Pb-responsive miRNAs and six target genes were validated by quantitative Real-Time PCR (qRT-PCR). These results provide fundamental insights into the miRNA-mediated regulatory networks and molecular mechanisms underlying plant responsiveness to Pb stresses.

作者：联川生物

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