环境因子对药用植物次生代谢的调控作用是中药材疗效品质形成的重要基础。然而，目前对环境因子调控药用植物次生代谢的机制尚不十分清楚。太阳光UVB对植物黄酮合成具有广泛调控作用，是研究环境因子调控植物次生代谢机制的重要模型。我们前期研究发现，由NIA1基因触发的NO迸发是介导UVB诱发植物黄酮合成的重要信号转导途径，但是目前对该途径的其它信号转导成员所知甚少。最近研究表明，小RNA可以响应外界UVB刺激并参与药用植物次生代谢的调控作用。然而，目前尚不清楚小RNA与NO是否可以通过相同信号通路介导UVB诱发药用植物黄酮合成。本项目拟以银杏细胞为材料，采用靶基因定向匹配分析、体外验证及细胞内功能试验等手段发掘与NO通过相同通路介导UVB诱发银杏黄酮合成的小RNA，解析其与NO在介导UVB诱发银杏黄酮合成中的信号转导关系。研究结果对深入理解UVB调控药用植物黄酮合成的信号转导机制具有重要意义。

Regulation of secondary metabolism of medical plants by environmental factors plays important roles in formation of curative quality of the traditional Chinese medicine. However, the mechanisms involved in the regulation of secondary metabolism of medical plants by environmental factors are still largely unknown so far. Biosynthesis of flavonoids in plants is widely influenced by solar UVB, which is, therefore, considered to be a ideal model to investigate the mechanisms of the regulation of secondary metabolism of medical plants by environmental factors. In previous studies, we found that NO signaling triggered by NIA1 gene play a key role in mediating UVB-induced flavonoid biosynthesis in plants. However, the other signaling members of the pathway are still unknown. Recently, microRNAs have been reported to be involved in responding the biotic and abiotic stresses and in regulating secondary metabolism of medical plants. However, it is still unclear that whether microRNAs could mediate UVB-induced flavonoid biosynthesis through the NO-dependent signaling pathway. In this project, we plan to discover the microRNAs that mediate UVB-induced flavonoid biosynthesis via the same signaling pathway as NO and explore the relationship between microRNAs and NO in mediating UVB-induced flavonoid accumulation of Ginkgo biloba cells using the strategy of gain and loss of functions and deep sequencing technology. The results will be of great importance for understanding the molecular mechanisms in the regulation of secondary metabolism of medical plants by environmental factors.