College of Agronomy, Agricultural University of Hebei, Baoding, 071001, People's Republic of China.
Key Laboratory of Crop Growth Regulation of Hebei Province, Baoding, 071001, People's Republic of China.
Plant Cell Rep. 2018 Sep;37(9):1293-1309. doi: 10.1007/s00299-018-2313-6. Epub 2018 Jun 9.
Wheat miRNA member TaMIR1139 targets genes functional in various families and plays crucial roles in regulating plant Pi starvation tolerance. Through regulating target genes at posttranscriptional or translational level, plant miRNAs are involved in mediating diverse biological processes associated with growth, development, and responses to adverse stresses. In this study, we characterized the expression pattern and function of TaMIR1139, a miRNA member of wheat (T. aestivum) under Pi deprivation. TaMIR1139 precursor is also present in N. tabucum, suggesting the conserved nature of miR1139 across monocots and eudicots. TaMIR1139 targets seven genes within different families. The transcripts abundance of TaMIR1139 was induced upon Pi deprivation and the upregulated expression under Pi starvation was downregulated by the Pi recovery treatment, In contrast, the genes targeted by TaMIR1139 exhibited reduced transcripts upon Pi starvation and their downregulated expression was recovered by Pi-recovery condition, suggesting the regulation of them under TaMIR1139 through a cleavage mechanism. TaMIR1139 overexpression conferred the Pi-deprived plants improved phenotype, biomass, photosynthesis, and Pi acquisition. Transcriptome analysis identified numerous genes involving biological process, cellular components, and molecular function were differentially expressed in the TaMIR1139 overexpression lines, which suggests the TaMIR1139-mediated plant Pi starvation tolerance to be associated with the role of miRNA in extensively modulating the transcript profiling. A phosphate transporter (PT) gene NtPT showed significantly upregulated expression in TaMIR1139 overexpression lines; overexpression of it conferred plants improved Pi acquisition upon Pi starvation, suggesting its contribution to the TaMIR1139-mediated plant low-Pi stress resistance. Our investigation indicates that TaMIR1139 is critical in plant Pi starvation tolerance through transcriptionally regulating the target genes and modulating the Pi stress-defensiveness processes.
小麦 miRNA 成员 TaMIR1139 靶向功能多样的基因家族，并在调控植物磷饥饿耐受中发挥关键作用。通过在转录后或翻译水平调节靶基因，植物 miRNA 参与介导与生长、发育和应对不利胁迫相关的多种生物学过程。在本研究中，我们对 TaMIR1139 的表达模式和功能进行了表征，TaMIR1139 是小麦（T. aestivum）在缺磷条件下的 miRNA 成员。TaMIR1139 前体也存在于 N. tabucum 中，表明 miR1139 在单子叶植物和双子叶植物中具有保守性。TaMIR1139 靶向七个不同家族的基因。TaMIR1139 的转录物丰度在缺磷时被诱导，而在磷饥饿下的上调表达在磷恢复处理时被下调。相反，TaMIR1139 靶向的基因在磷饥饿时转录物丰度降低，其下调表达在磷恢复条件下恢复，表明它们在 TaMIR1139 调控下通过切割机制。TaMIR1139 过表达赋予缺磷植物改善的表型、生物量、光合作用和磷获取。转录组分析鉴定了许多参与生物学过程、细胞成分和分子功能的基因在 TaMIR1139 过表达系中差异表达，这表明 TaMIR1139 介导的植物磷饥饿耐受与 miRNA 在广泛调节转录谱中的作用有关。一个磷酸盐转运蛋白（PT）基因 NtPT 在 TaMIR1139 过表达系中表现出显著上调表达；过表达它赋予植物在磷饥饿时改善的磷获取能力，表明其对 TaMIR1139 介导的植物低磷胁迫抗性的贡献。我们的研究表明，TaMIR1139 通过转录调控靶基因和调节磷胁迫防御过程，在植物磷饥饿耐受中至关重要。
