离体模型指导下促沉香形成的真菌诱导子发现

Aquilaria sinensis is a rare and endangered medicinal plant in China. It is recognized that fungi activate its defense response to form agarwood, which is used as traditional medicine and perfume. Up to now, however, there are no reports about fungal elicitors which could promote agarwood formation. In our previous work, endophytic fungal strains, Fusarium sp. A2 and Botryosphaeria rhodina A13 were found to play an important role in agarwood formation, and Fimetariella rabenhorstii A20 could produce similar chemical constituents of agarwood. In this study, an in vitro model will be creatd by artificially inoculating excised twigs of Aquilaria sinensis with these strains. After a period of culture, characteristic components such as sesquiterpenoid and 2-(2-phenylethyl) chromone in twigs will be analyzed by using GC/MS and LC/MS. In order to find fungal elicitors, the strains will be cultured in liquid medium, and metabolities in fermentation extracts will be isolated, purified and identified, guided by using an in vitro model. This study will reveal the role of fugal elicitors in the process of agarwood formation and provide an important theoretical basis for analysis of agarwood formation mechnism. Therefore, it has guiding significance to control process of agarwood formation, to develop an efficient artificial technology for inducing agarwood formation, accelerating agarwood production and improving the quality of agarwood .

白木香是我国特有珍稀濒危药用植物，真菌能诱导其防御反应，生成传统中药和香料沉香，目前关于促进沉香形成的真菌诱导子研究未见报道。在我们前期研究中，发现内生真菌镰刀菌（Fusarium sp. A2）、葡萄座腔菌（Botryosphaeria rhodina A13）能显著促进白木香结香，Fimetariella rabenhorstii A20能生成沉香相似组分。本项目将以它们为研究材料，将菌株接种于离体白木香，建立离体模型，采用GC-MS、LC-MS技术分析产生的倍半萜类、2-2苯乙基色酮类沉香特征性成分，并通过在离体模型条件下的活性跟踪，对3个菌株进行发酵培养、分离纯化和结构鉴定，从中寻找促进沉香形成的诱导子。本研究将对揭示真菌诱导子在沉香形成过程中的作用，深入剖析沉香形成机理提供重要理论依据，也将对调控白木香结香过程，研究高效人工促香技术，加快沉香生产速度，提高沉香品质具有指导意义。

我们前期研究发现内生真菌镰刀菌（Fusarium sp. A2）、葡萄座腔菌（Botryosphaeria rhodina A13）能显著促进白木香结香，而菌株Fimetariella rabenhorstii A20则能生成沉香相似组分。本项目以它们为研究材料，将菌株接种于离体白木香枝条，建立离体模型，采用GC-MS、LC-MS技术分析产生的倍半萜类、2-2苯乙基色酮类沉香特征性成分。进而通过在离体模型条件下的活性跟踪，对3个菌株进行发酵培养、分离纯化和结构鉴定，共分离鉴定了32个单体化合物，其中11个色酮类物质为沉香的特征性成分，并且发现新结构化合物2个。通过离体枝条实验发现菌株A13的粗提物可促进结香，经GC-MS、LC-MS分析发现菌株A13经白木香木屑培养后的乙酸乙酯粗提物能够检测到沉香特征性成分倍半萜类化合物。因此，上述究结果为内生真菌诱导沉香的形成提供了重要理论依据，同时，对研究高效人工促香技术以及调控白木香结香过程具有指导意义。