miRNA-mediated post-transcriptional regulation of gene expression in ABR17 transgenic Arabidopsis thaliana under salt stress. Arabidopsis thaliana

Micro RNAs (miRNAs) are a class of small endogenous RNAs conserved in eukaryotic organisms including plants. They suppress gene expression post-transcriptionally in many different biological processes. Previously, we reported salinity-induced changes in gene expression in transgenic Arabidopsis thaliana plants that constitutively expressed a pea abscisic acid-responsive (ABR17) gene. In the current study, we used a microarray to investigate the role of miRNA-mediated post-transcriptional gene regulation in these same transgenic plants in the presence and absence of salinity stress. We identified nine miRNAs that were significantly modulated due to ABR17 gene expression, and seven miRNAs that were modulated in response to salt stress. The target genes regulated by these miRNAs were identified using starBase (sRNA target Base) Degradome analysis and through 5' RNA Ligase Mediated-Rapid Amplification of cDNA Ends (RLM-RACE). Our findings revealed miRNA:mRNA interactions comprising regulatory networks of Auxin Response Factor (ARF), ARGONAUTE 1, (AGO1), Dicer-like proteins 1 (DCL1), Squamosa Promoter Binding (SPB), NAC, APETALA 2 (AP2), Nuclear Factor-Y (NFY), RNA binding proteins, Arabidopsis thaliana vacuolar phyrophosphate 1 (AVP1) and Pentatricopetide repeat (PPR) in ABR17 transgenic A. thaliana, which control physiological, biochemical and stress signalling cascades due to the imposition of salt stress. Our results are discussed within the context of the effect of the transgene, ABR17, and the roles miRNA expression may play in mediating plant responses to salinity. Overall design: In this miRNA-microarray experiment, a total of 4 samples were analyzed with their 3 biological replicates. Two samples, WT and ABR17 control (without salt treatment), were used as reference controls.

微RNA（micro RNAs, miRNAs）是一类广泛存在于包括植物在内的真核生物中的小型内源RNA，可在诸多生物学过程中通过转录后调控机制抑制基因表达。此前本团队曾报道，组成型表达豌豆脱落酸响应（ABR17）基因的转基因拟南芥（Arabidopsis thaliana）在盐胁迫下的基因表达变化。本研究采用基因芯片（microarray）技术，探究了盐胁迫与非盐胁迫条件下，miRNA介导的转录后基因调控在上述转基因拟南芥中的作用。我们共鉴定出9个受ABR17基因表达显著调控的miRNA，以及7个响应盐胁迫的miRNA。通过starBase（小RNA靶标数据库，sRNA target Base）降解组分析，结合5' RNA连接酶介导的cDNA末端快速扩增技术（RLM-RACE），我们鉴定了这些miRNA的靶基因。研究结果揭示了由这些miRNA与mRNA相互作用构成的调控网络，其涉及的靶基因包括生长素响应因子（ARF）、ARGONAUTE 1（AGO1）、Dicer样蛋白1（DCL1）、Squamosa启动子结合蛋白（SPB）、NAC转录因子、APETALA 2（AP2）、核因子Y（NFY）、RNA结合蛋白、拟南芥液泡焦磷酸酶1（AVP1）以及五肽重复蛋白（PPR），这些靶基因可介导盐胁迫下植物的生理、生化及应激信号通路调控。本研究结果围绕转基因ABR17的作用效应，以及miRNA表达在介导植物响应盐胁迫过程中可能发挥的功能展开讨论。实验整体设计：本miRNA基因芯片实验共分析4组样本，每组设置3次生物学重复。其中野生型（WT）与ABR17对照（未施加盐处理）两组作为参考对照。