内生菌与植物间互作影响内生菌多样性及植物活性成分积累，基于文献报道和前期相关研究积累，项目提出：铁皮石斛内生菌促进其活性成分积累是通过内生菌诱导石斛多糖和生物碱合成途径中关键酶表达而实现的假说，项目拟在探明内生菌多样性（种群、代谢物）基础上，开展铁皮石斛内生菌促进其活性成分积累的机理研究。研究思路：（1）通过PCR-DGGE及454焦磷酸测序技术分析铁皮石斛内生菌多样性，筛选功能菌株并分离鉴定功能菌的代谢物，探讨内生菌代谢物多样性。（2）应用植物细胞与组织培养方法，从细胞与植株两水平研究筛选并研究有益内生菌对铁皮石斛活性成分生物合成的诱导作用；（3）应用分子生物学、微生物学、现代波谱技术以及主成分分析(PCA)等方法研究有益内生菌对铁皮石斛活性成分合成途径关键酶的影响。揭示铁皮石斛内生菌促进其活性成分积累的机理，为从内生菌角度阐明中药材品质及道地性形成进行前期探索与实践。

The diversity of endophytes and accumulation of active components of the host plant are impacted by each other. Based on the reports and our pilot studies, our hypothesis is that endophytes induce the accumulation of the polysaccharides and alkaloids of Dendrobium officinale by impacting the key enzymes of the synthetic way of polysaccharides and alkaloids of Dendrobium officinale. The project will research the diversity of endophytes (species distribution, metabolites) and the mechanism which endophytes promote accumulation of active components of Dendrobium officinale. We will analysis diversity of endophytes through PCR-DGGE and 454 focal phosphoric acid sequencing technology, screen functional strains, isolate and identify the metabolites of endophytes, discusse the diversity of metabolites. We will study on how the endophytes induce accumulation of active components of Dendrobium officinale from cell and plant levels by plant cell and tissue culture method. We will research how the picked strains affect the key enzymes of the synthetic way of polysaccharides and alkaloids of Dendrobium officinale by application of molecular biology, microbiology, modern spectrum technology and principal component analysis. Reveal the mechanism of promoting the accumulation of active components and expound how the endophytes effect the quality of chinese herbal medicine.