三株海南特有红树植物内生真菌抗炭疽病真菌的化学成分研究

Mangroves are trees or shrubs growing in saline coastal habitats in the tropics and subtropics. Owing to their unique ecological environment, they are promising sources for the isolation of endophytic fungi, which are considered to be bank of novel bioactive compounds. In our pilot work, we found the extracts of the fermentation broth of twelve strains of endophytic fungi isolated from Sonneratia hainanensis and Acrostichum specioum exhibited inhibitory activities against Colletrichum spp. Yet secondary metabolites of endophytic fungi from these two endemic mangrove in Hainan have not been studied. On that basis, the selected three talent strains will be induced, cultured, and large-scale fermented on the optimal conditions. Then screening for secondary metabolites with novel structures by HPLC-MS-UV and 1H-NMR methods will be conducted. The bioactive and new metabolites of endophytic fungi will be purified by various chromatographic methods and identified by NMR techniques under the anti-phytopathogen activity guided fractionation. After confirming the activity, we will investigated the structure modification of the bioactive novel compounds and their structure-activity relationship. The new research findings will offer new lead compounds for the development of biogenic natural pesticides and antistaling agent of tropical fruit, and provide important theoretical foundation for the application of endophytic fungi derived from endemic plants in Hainan into the research and development of bio-control products used in tropical agriculture..

红树林（mangrove）是热带亚热带海岸潮间带的特殊植物群落，其独特的生态环境使其内生真菌成为寻找生物活性物质的重要来源。海南海桑（Sonneratia hainanensis）和尖叶卤蕨（Acrostichum specioum）为海南特有红树植物，目前尚未见其内生真菌的活性天然产物研究报道。申请者前期已从中分离筛选得到12株具有抗橡胶、香蕉和芒果炭疽病真菌的内生真菌，本课题将选取其中3株活性较强的潜力菌株进行大规模发酵和诱导培养，在抗真菌活性追踪指导下，运用1H-NMR和HPLC-MS-UV方法进行产结构新颖性化合物筛选，利用现代分离分析技术从产物中分离鉴定出新活性成分，并进行活性确认、结构修饰和构效关系研究，从而为热区作物的真菌病害防治及热带水果保鲜用药提供新型先导化合物，为海南珍稀植物内生真菌资源运用于热带农业生物源农药研发提供理论依据。

由微生物产生的代谢物作为农药已成为微生物源农药主体之一，而创新微生物源农药的首要任务是寻找（新型）活性天然产物，其中，植物内生真菌是用于生物防治或提供对环境无害农药的一种重要新来源。红树林湿地是世界自然环境现存重要的生物基因库，蕴藏着大量的菌物资源，为挖掘海南特有红树内生真菌资源，保护珍贵红树植物，本项目对来源于海南红树植物海南海桑、尖叶卤蕨、角果木的6株内生真菌菌株次生代谢产物进行了分离纯化、结构鉴定与活性筛选，已从中分离鉴定了63个化合物，包括新（结构）天然产物23个，其结构类型多样，主要为新酸酐类、新倍半萜、新呋喃类结构。体外生物活性筛选发现其中一些（新）化合物具有较好的抗农业病原菌、杀虫、抗肿瘤及乙酰胆碱酯酶抑制活性。该研究结果进一步表明红树植物内生真菌是寻找新型活性天然产物的重要来源。