谢瓦曲霉Aspergillus chevalieri BYST01中大黄素甲醚的生物合成机制

大黄素甲醚是主要存在于中药大黄中的天然蒽醌化合物，已被我国自主开发为新型植物源杀菌剂，但大黄中大黄素甲醚含量低，生产成本高。微生物代谢工程技术可以提高代谢产物产量，构建高产大黄素甲醚工程菌株具有重要意义。申请人前期从黑翅土白蚁肠道中发现一株高产大黄素甲醚(28 mg/L)真菌谢瓦曲霉Aspergillus chevalieri BYST01，并通过基因组分析获得参与大黄素甲醚生物合成的候选基因。在此基础上，本项目拟通过米曲霉真核异源表达体系验证大黄素甲醚生物合成通路；利用原核异源表达和酶活性分析等方法，研究关键酶的体外催化功能；进一步通过基因敲除技术，挖掘出合成基因簇中影响大黄素甲醚含量积累的其它基因。项目的实施将明确大黄素甲醚的生物合成途径，为BYST01菌中大黄素甲醚产量的提高奠定一定的基础，具有潜在的经济和社会效益。

Physcion is a natural anthraquinone, which is mainly found in the traditional Chinese medicine materials (Rheum palmatum L). It has been independently developed as a new plant-derived fungicide by our country. However, the physcion from plant materials has high production costs for the low content in R. palmatum. The metabolic engineering technology of microorganisms can greatly increase the yield of their bioactive metabolites. It is of great significance to construct an engineering strain with high physcion yield. In our previous studies, a fungus of Aspergillus chevalieri BYST01 was isolated from the gut of Odontotermes formosanus with a high yield of physcion (28 mg/L). Furthermore, the candidate genes involved in the biosynthesis of physcion were obtained by genome analysis. On this basis, this project intends to verify the biosynthesis pathway of physcion by using the eukaryotic heterologous expression system of Aspergillus oryzae. We will further study the catalytic function of key enzymes in vitro by the methods of prokaryotic heterologous expression and enzyme activity analysis. Finally, other genes that affect the accumulation of physcion in the synthetic gene cluster will be explored through gene knockout technology. The project will clarify the biosynthesis pathway of physcion and lay a foundation for the increase of physcion yield in BYST01. It has potential economic and social benefits.