丹参miR828和miR858参与次生代谢调控的分子机制

丹参是传统中药材，正成为模式药用植物。丹参全基因组序列测定已基本完成，次生代谢产物丹参酮和酚酸等合成途径的关键酶基因研究也已取得进展，但其分子调控机理还很不清楚。基于前期对丹参次生代谢产物生物合成相关基因、miRNA和MYB转录因子的研究结果，我们认为miR828和miR858是丹参次生代谢的重要调控因子。为了验证这一假设，本项目将构建miR828和miR858过表达载体，转化丹参，比较分析转基因和非转基因丹参主要次生代谢产物含量的变化，高通量分析丹参降解组和转录组数字表达谱，从组学水平找出受miR828和miR858直接调控或间接影响的基因，揭示miR828和miR858与蛋白质编码基因和主要次生代谢产物之间的关系，构建miR828和miR858的调控网络并探讨其作用机制，为彻底揭示丹参药用活性成分生物合成的遗传控制机制和利用基因工程手段获得药用活性成分含量高的新品系奠定基础。

Salvia miltiorrhiza Bunge is a well-known material of traditional Chinese medicine (TCM). It is also an emerging model plant for TCM studies. The genome of S. miltiorrhiza has been preliminarily decoded and significant research progress has been made in key enzyme genes involved in the biosynthesis of secondary metabolites, such as tanshinones and phenolic acids; however, the regulatory mechanism of secondary metabolism is largely unknown. Based on our results from the studies on secondary metabolite biosynthesis-related genes, miRNAs and MYB transcription factors, we assume that miR828 and miR858 play significant regulatory roles in the biosynthesis of secondary metabolites in S. miltiorrhiza. With the aim to test this hypothesis, we propose to construct miR828 and miR858 overexpression vectors and then introduce them into S. miltiorrhiza. The content of main secondary metabolites in transgenics and non-transgenics will be analyzed comparatively. High-throughput degradome sequencing and RNA-seq will be performed for transcriptome-wide analysis of genes directly cleaved or indirectly regulated by miR828 and miR858. All of the data obtained will be further comprehensively analyzed for elucidating the relationships among miR828, miR858, protein-coding genes, and the production of main secondary metabolites in S. miltiorrhiza. We expect that the regulatory network of miR828 and miR858 in secondary metabolism will be constructed and the regulatory mechanism will be finally elucidated. The results will provide useful information for understanding the genetic regulatory mechanism in the biosynthesis of S. miltiorrhiza bioactive compounds and will serve as a basis for development of new S. miltiorrhiza lines with high bioactive compound content through genetic engineering approaches.