植物细胞培养过程中次生代谢产物产量不稳定，是制约其产业化的“瓶颈”。解析红豆杉细胞紫杉醇生物合成机制有助于提高细胞培养生产紫杉醇的产业化水平。miRNA是在转录后水平作用的调控因子，参与很多重要发育及代谢过程。我们前期研究发现一个特异性miRNA（miR5298b），其可能是通过调控多个转录因子来极显著调控紫杉醇合成。本研究拟以长期继代低产细胞系CA及新诱导高产细胞系NA为研究材料，首先利用降解组测序和RACE等技术鉴定miR5298b的靶标基因（转录因子）和途径，进而深入研究这些靶标转录因子调控紫杉醇合成机制，明确miR5298b-转录因子调控紫杉醇合成的节点和网络，最后构建miR5298b及其关键靶标基因的共表达转基因细胞系，并评价其应用潜力。研究结果不仅可以丰富紫杉醇生物合成的转录调控理论，还将为红豆杉细胞系的基因工程改良提供依据。项目的完成对于其它药用植物细胞培养有很好的指导意义。

Plant-cell technology is a promising way to produce precious secondary metabolites, while the industrial process was limited by the instability production of taxol during subculture process. The exploration of the taxol synthesis mechanism in cells is helpful to improve the culture level of industrialization. As we all know, miRNA is an important post-transcriptional regulators involving in regulating biosynthesis of metabolites in plants. In our previous studies, a conserved miRNA, miR5298b was identified as an effective regulator of taxol biosynthesis, network analysis indicated that miR5298b was more likely to affect the expression level of transcription factors to regulate the taxol biosynthesis. Here, we use two subcultured cell lines, CA (low-content of taxol) and NA (high-content of taxol) for further study. Firstly, degradome and RACE are used to identify target transcription factors of miR5298b. Then these targets are functionally analyzed to select the key transcription factors and clarify their regulation mechanisms on taxol biosynthesis. Afterwards, the regulation mechanism of miR5298b-transcription factors-taxol biosynthesis is concluded. Finally, a transgenic cell line, that both miR5298b and the key factor are genetic modified, is constructed to evaluate the industrial value on producing taxol. Our results would not only enlarge the understanding of taxol regulation system, but also provide advices for genetically engineering of Taxus cells. It is very meaningful for plant-cell technology to produce other secondary metabolites.