禾谷镰刀菌诱导海南龙血树血竭主要活性物质积累的分子机制

Dracaena cambodiana is the main important resource plant for dragon's blood production in China. As the Traditional Chinese Medicine, the dragon's blood from D.cambodiana has various pharmacological properties, such as invigorating the circulation of blood, anti-inflammatory, analgesic activities and so on. The medicine research and development about dragon's blood in China is limited by its formation slowly and very little, and the study about its formation mechanism in Dracaena will help us product more dragon's blood. The previous studies indicated that dragon's blood in Dracaena were effectively induced by Fusarium graminearum, whereas its inductive mechanism is still unknown. Our previous studies demonstrated that acetic acid and 6-BA could more effectively induce dragon's blood formation in D.cambodiana. Acetic acid and 6-BA are the important secretory elicitors of plant fungus, which might suggest that F.graminearum induce dragon's blood formation through its elicitors. Based on this phenomenon and hypothesis, transcriptomics and chemical fingerprint will be used for investigating the kinds and secretary features of elicitors in F. graminearum and their specific roles for dragon's blood formation in Dracaena interactive with them, eventually the regulatory mechanism of active substances accumulated of dragon's blood in D. cambodiana induced by F.graminearum and its elicitors will be furtherly studied. These studies present here will provide new insight of molecular mechanism research of dragon's blood formation and its major active substances accumulation, and also contribute to develop bionic inducer for dragon's blood formation with artificial induce technology. Ultimately, this project will afford critically theoretic and technological foundation for utilizing endangered D.cambodiana tree to product dragon's blood efficiently.

海南龙血树是国产血竭的重要基源植物，其血竭以良好的活血化瘀、消炎镇痛等药理作用成为珍贵的传统药物。血竭生成缓慢限制着我国血竭类药物的研发，而其生成机制的研究则是解决这一问题的关键。前人研究表明禾谷镰刀菌能有效诱导龙血树血竭的生成，但其诱导机制尚不清楚。课题组前期研究则发现真菌分泌的乙酸等诱导子能更为高效地诱导海南龙血树血竭生成，而禾谷镰刀菌是否是通过其诱导子介导海南龙血树血竭生成的研究鲜有报道。本项目拟以禾谷镰刀菌诱导龙血树血竭生成现象为切入点，通过分析禾谷镰刀菌诱导子的种类、分泌特征及其诱导效应，并结合化学指纹图谱和转录组学的方法重点探讨禾谷镰刀菌及其诱导子对海南龙血竭及其主要活性物质积累的调控机理。这些研究将为龙血树血竭及其主要活性成分积累研究提供分子生物学水平的证据，也为进一步合理利用这些特性研发血竭仿生诱导剂，最终实现濒危海南龙血树种质资源的高效利用提供重要的理论和技术支撑。

海南龙血树是国产血竭的重要基源植物，其血竭以良好的活血化瘀、消炎镇痛等药理作用成为珍贵的传统药物。血竭生成缓慢限制着我国血竭类药物的研发，而其生成机制的研究则是解决这一问题的关键。禾谷镰刀菌可诱导海南龙血树血竭的生成。本项目通过分析禾谷镰刀菌诱导子的种类及其诱导效应，并结合化合物含量和转录组学的方法研究了禾谷镰刀菌及其诱导子对海南龙血竭及其主要活性物质积累的调控机理。本研究将禾谷镰刀的菌的诱导子分为4类，茎干诱导实验发现禾谷镰刀菌孢子培养液上清液具有较好的诱导血竭生成效应；禾谷镰刀菌接种后的海南龙血树茎干的转录组测序分析表明健康茎干的基因表达模式与诱导后茎干的基因表达模式不同；进一步的富集分析发现酮类合成途径差异基因的数量及其比例均高于萜类合成途径，56%（112个）的苯丙烷途径途径基因和47%（116个）的植物-病原菌互作途径基因为差异表达，病程相关蛋白PR4家族和21个PR9成员在禾谷镰刀菌与海南龙血树的互作中显著上调表达，说明酮类合成及血竭生成的同时伴随着植物的防御反应的发生；4种诱导子处理后的qPCR发现，禾谷镰刀菌及其诱导子与海南龙血树互作前期优先激活了JA途径，而侵染的后期则触发了SA途径基因表达。海南龙血树防御途径的激活及其所产血竭中黄酮类化合物的抑菌活性说明血竭可能是海南龙血树防御反应的产物，该假说也在化学诱导实验的转录组数据和qPCR中得到验证。本项目执行过程中，发表学术论文4篇，其中SCI收录2篇，申请国家发明专利2项，培养硕士研究生1名。本项目的研究为龙血树血竭及其主要活性成分积累研究提供分子生物学水平的证据，也为进一步合理利用这些特性研发血竭诱导剂，最终实现濒危海南龙血树种质资源的高效利用提供重要的理论和技术支撑。