植物种属小分子RNA（miRNAs）通过转录后和翻译水平调节，在介导植株抵御非生物逆境过程中发挥着重要作用。申请人前期对小麦miRNA家族成员应答低钾胁迫的研究发现，TaMIR1118在低钾处理下表达水平显著上调，而其作用靶基因钙调素TaCaM2家族基因TaCaM2-1~TaCaM2-3应答低钾特征与该miRNA相反，表明TaMIR1118/TaCaM2模块在介导植株应答低钾胁迫中发挥重要功能。本项研究以该miRNA功能模块为基础，利用RLM-RACE 和PPM-RACE技术，鉴定供试miRNA靶基因TaCaM2-1~TaCaM2-3转录本剪切特征；采用基因过表达和RNAi干涉技术，系统研究上述模块成员介导植株抵御低钾逆境能力；采用转录组测序和蛋白谱检测技术，鉴定TaMIR1118调控的低钾响应基因、分子网络和生化代谢途径。通过本研究解析TaMIR1118介导植株抵御低钾胁迫的分子机理。

Through regulation of the target genes at posttranscriptional and translational levels, microRNAs (miRNAs) play critical roles in mediating plant abiotic stress responses via modifying the target transcripts abundance. Our previous expression studies on wheat miRNA family members responding to potassium deprivation revealed that a miRNA member TaMIR1118 showed significantly upregulated expression upon low-K stress. In contrast, its target genes including camodulin encoding genes TaCaM2-1, TaCaM2-2, and TaCaM2-3 exhibited reverse expression patterns in response to potassium deficiency contrasting with TaMIR1118, suggesting that the TaMIR1118/TaCaM2-1~TaCaM2-3 module functions largely in mediating plant low-K stress tolerance. In this current project, by using RLM-RACE and PPM-RACE techniques, we will experimentally assay the cleaved characterization of the target genes TaCaM2-1, TaCaM2-2, and TaCaM2-3 under TaMIR1118. By adopting gene overexpression and RNAi gene knockdown approaches, we will elucidate the function of module members in mediating plant low-K stress tolerance. In addition, high throughput RNA-seq and proteomics techniques will be applied to identify the differential genes associated with plant potassium deprivation tolerance under the control of the miRNA member, by which to establish the corresponding molecular networks and biochemical metabolic pathways that contribute to the miRNA/target module-modulated low-K stress tolerance. This project will unravel the molecular mechanism as to how TaMIR1118 mediates the low-K stress tolerance of plants in wheat.