利用异源表达激活丝状真菌中的沉默天然产物生物合成基因/基因簇，是一条行之有效地定向发现新天然产物的途径。然而，受异源宿主和表达载体的局限性，使得该方法的应用，尤其在表达大片段（>50 kb）基因簇时遇到了很大的困难。我们预实验首次针对米曲霉构建的丝状真菌人工染色体可以在大肠杆菌和米曲霉中自由穿梭。为此我们提出假说：米曲霉丝状真菌人工染色体系统或可解决真菌大片段沉默基因簇异源表达的难题。为了验证这一假说，我们将利用构建好的人工染色体系统针对一株来源于药用植物滇重楼的内生杂色曲霉构建基因组文库，结合生物信息学分析杂曲霉基因组，并对文库进行筛选，定位潜在的沉默基因簇，最后将携带基因簇的质粒转化到米曲霉中进行异源表达，挖掘全新的天然产物。本研究将从米曲霉人工染色体异源表达药用植物内生真菌大片段基因簇，挖掘新天然产物这个新视点为激活丝状真菌沉默基因簇，定向发现新活性天然产物提供一定的思路。

Heterologous expression is one of the best way to activate of the silent Natural Product Biosynthesis Gene Cluster (NPBGC) for guiding isolation of novel natural products from the filamentous fungi. However, it is very difficult to use this method to express large fragment NPBGC (>50 kb) for the limited heterologous host and vector. The pre-experimental results showed that the Fungal Artificial Chromosomes (FAC) could be successfully shuttled between Escherichia coli and the heterologous expression host Aspergillus oryzae. This is the first time to construct a FAC based on heterologous expression host Aspergillus oryzae in the world. Therefore, we hypothesized that the FAC constructed by us might be used to heterologous express of the large fragment NPBGC originated from filamentous fungi. In order to verify this hypothesis, we firstly intend to construct a gDNA library for one strain of endophytic Aspergillus versicolor isolated from Paris polyphylla var. yunnanensis. Secondly, we will use bioinformatics method to analyze the genome sequence of the Aspergillus versicolor and then filtering the gDNA library and finding the cryptic NPBGC. Lastly, we will use PEG guided protoplast transformation method to transform the selected NPBGC into the heterologous expression host Aspergillus oryzae to find the novel natural product. This project will firstly use FAC constructed based on the Aspergillus oryzae heterologous expression host to activate of the large fragment silent NPBGC originated from endophytic fungi isolated from medicinal plant to find novel natural product. In addition, we also hope that this project could provide new ideas for guiding discovering novel bioactive natural product from natural source.