一个全新miRNA PC-3p-1在甘薯盐胁迫响应中的功能及调控机理研究

Soil salinity severely restricts the development of sweet potato agriculture and other relative industries. MicroRNAs (miRNAs) play an essential role in the abiotic stress responses in plants. However, miRNAs involved in salt tolerance in sweet potato have not been reported yet. By using small RNA sequencing, transcription profiling and degradome sequencing, we have identified a novel salt responsive miRNA PC-3p-1 in sweet potato. And miRNA PC-3p-1 has not been reported in other plant species so far. The analysis of degradome sequencing and RACE-PCR indicated that the IbRBP47C is the target gene of PC-3p-1. This project aims to study the function of the salt induced miRNA PC-3p-1 and its target gene in sweet potato. The PC-3p-1 silencing, the PC-3p-1 over-expression and IbRBP47C over-expression transgenic sweet potato lines will be generated. The morphological phenotype and physiological characteristics of transgenic sweet potato lines will be analyzed to explore the function of miRNA PC-3p-1 and its target under salt stress. The downstream regulatory network of miRNA PC-3p-1 and its target will be analyzed as well. This study will extend our knowledge in the aspect of understanding the regulatory mechanism of sweet potato miRNAs in response to salt stress, and accomplishment of this project will provide theoretical basis and novel strategies for trait improvement of sweet potato under adversity stresses.

土壤盐渍化严重制约着甘薯农业及其相关产业的发展。miRNA在植物逆境胁迫响应过程中发挥着重要的调控作用。然而，在甘薯中仍未见盐胁迫响应miRNA的相关研究报道。本实验室通过分析甘薯小RNA文库、转录组和降解组文库，鉴定到一个在其他物种中未见报道的参与盐胁迫响应的特异miRNA PC-3p-1。降解组测序及嵌套RACE-PCR的结果显示PC-3p-1的靶基因为IbRBP47C。本项目将通过沉默miRNA PC-3p-1表达、过表达miRNA PC-3p-1、过表达RBP47C等分子生物学和遗传学手段，检测不同转基因甘薯株系对盐胁迫的耐受性和相应生理生化指标，分析miRNA PC-3p-1在甘薯耐盐过程中的功能及其作用机理，探究miRNA下游基因的表达调控网络。本研究的开展将有助于理解和阐明miRNA响应盐胁迫的网络调控机制，同时为甘薯在逆境胁迫下的性状改良提供理论依据和新途径。

土壤盐渍化严重制约着甘薯农业及其相关产业的发展。miRNA在植物逆境胁迫响应过程中发挥着重要的调控作用。然而，在甘薯中盐胁迫响应miRNA的相关研究报道非常少。本课题以甘薯为试验材料，利用高通量测序技术鉴定了Xu32和Xu22两个甘薯品种中已知的miRNA和新的miRNA；结合甘薯miRNA在盐胁迫和非胁迫条件下的表达谱，找出与盐胁迫响应相关的miRNA；通过降解组和实时荧光定量PCR数据的分析，鉴定甘薯响应盐胁迫的miRNA的靶基因，并利用GO和KEGG进一步分析了它们的网络调控关系；同时，在两个不同基因型的甘薯品种中分析并挖掘出数个与耐盐性状关系密切的miRNA。本研究阐明了响应盐胁迫的甘薯miRNA与其靶基因之间的调控网络关系，为进一步揭示甘薯盐胁迫抗性的分子机制和培育出高耐盐性甘薯品种奠定了坚实的理论基础。