杭白菊MicroRNA156参与介导UV-B诱发黄酮合成的调控机制研究

Regulation of secondary metabolism by environmental factors plays important roles in formation of curative quality of the traditional Chinese medicine. Biosynthesis of flavonoids in plants is widely influenced by solar UV-B, which is, therefore, considered to be an ideal model. However, the regulation mechanism of this pathway is not clear. Our previous study showed that microRNA156 was induced by UV-B treatment and regulated UV-B-induced flavonoid biosynthesis in Chrysanthemum morifolium Ramat. Thus it is a newly found important regulatory gene in this pathway. In this study, Chrysanthemum morifolium Ramat is used as the research object. The expression pattern of miR156 and the target gene CmSPL9 under UV-B treatment will be examined. Transgenic plants of miR156 overexpression, miR156 target mimicry and cleavage site mutation of CmSPL9 will be constructed. The accumulation of flavonoids during UV-B treatment will be detected, and the flavonoid biosynthesis related genes which is regulated by this pathway will be screened. Furthermore, the regulation of miR156-CmSPL9 in UVR8 signaling pathway will be checked using VIGS technology. Finally, the regulatory mechanism of miR156-CmSPL9 involved in mediating UVB-induced flavonoid biosynthesis will be revealed. The results will be of great importance for further understanding the molecular mechanisms in the regulation of flavonoids by UV-B in medical plants.

环境因子通过调控次生产物的合成影响中药材疗效品质，太阳光UV-B调控黄酮合成是其中的重要模型，但其调控机制尚不清楚。申请人前期研究发现，杭白菊miR156受UV-B诱导表达，参与介导UV-B诱发黄酮合成，是该途径中新发现的重要调控因子。本项目拟以杭白菊为研究对象，检测UV-B处理时miR156与靶基因CmSPL9的表达量，研究其表达调控模式；获得miR156过表达、靶基因模拟与CmSPL9剪切位点突变转基因材料，检测UV-B处理时黄酮积累量的变化，筛选受调控的黄酮合成相关基因，探明miR156-CmSPL9对UV-B诱发黄酮合成的影响及其调控模式；采用VIGS技术考查miR156-CmSPL9在UV-B受体UVR8信号途径中的作用机制；进而揭示miR156-CmSPL9参与介导UV-B诱发黄酮合成的调控机制。研究结果对进一步理解UV-B调控药用植物黄酮合成的作用机制具有重要意义。

环境因子通过调控次生产物的合成影响中药材疗效品质，太阳光UV-B调控黄酮合成是其中的重要模型，但其调控机制尚不清楚。本项目以杭白菊为研究对象，研究miR156通过靶基因CmSPL9参与介导UV-B诱发黄酮合成的调控机制。通过检测UV-B处理时miR156与靶基因CmSPL9转录因子的表达量，研究其表达调控模式；通过双荧光素酶报告基因检测，研究miR156与靶基因CmSPL9转录因子的相互关系；获得miR156过表达、靶基因模拟与CmSPL9剪切位点突变转基因材料，检测UV-B处理时黄酮积累量的变化，筛选受调控的黄酮合成相关基因与关键转录因子，探明miR156-CmSPL9对UV-B诱发黄酮合成的影响及其调控模式；采用VIGS技术考查miR156-CmSPL9在UV-B受体UVR8信号途径中的作用机制。本项目的研究结果表明杭白菊miR156与靶基因CmSPL9依赖于UVR8信号通路参与介导UV-B诱发杭白菊黄酮合成。miR156-CmSPL9通过对晚期黄酮合成相关基因CmFLS3、CmF3’H、CmDFR与关键转录因子CmPAP1、CmTT8-1、CmGL3-1转录因子基因的表达调控，在UV-B信号通路中调控杭白菊黄酮合成。本项目解析了miR156通过靶基因CmSPL9参与介导UV-B诱发黄酮合成的信号通路，发掘了调控杭白菊黄酮合成代谢的miR156、CmSPL9、CmFLS3、CmF3’H、CmDFR、CmPAP1、CmTT8-1、CmGL3-1等多个分子改良靶点，为杭白菊疗效品质提升的分子育种打下基础，研究结果对进一步理解UV-B调控药用植物黄酮合成的作用机制具有重要意义。