茶树病原真菌和内生真菌的多样性及其分布规律

Tea (Camellia sinensis) diseases caused serious economic losses. However, as the basis of disease diagnosis and effective prevention, accurate identification of pathogen has not been satisfactorily solved. Taxonomy based on morphology and disease symptom causes chaos in the study of tea plant pathogens in the past years, which therefore needs accurate re-identification according to modern species concept and species identification protocols. Endophytic fungi compose another important microbial community in tea plant, whose taxonomy, biodiversity and distribution are in lack of systematic and comprehensive study. This project aims to study the pathogenic and endophytic fungi associated with tea plant using combined morphological and molecular techniques; clarify their species distribution and diversity, and their relationship with ecological environment. The obtained cultures in this project will provide good resources for screening of new antagonistic fungi and new structure of biologically active compounds. It also lays the foundation for further study of the relationship between pathogenic and endophytic fungi. This project has important scientific significance in the control and management of plant diseases, and the conservation and utilization of endophytic fungi.

植物病原真菌引起的茶树病害每年造成严重的经济损失，然而作为病害诊断及有效防治的基础，即病原菌的准确鉴定问题一直没有得到科学的解决；内生真菌作为茶树上的另一重要的微生物群落，其分类学、生物多样性和分布规律目前尚缺乏系统全面的研究。本项目拟采用形态学和分子生物学相结合的方法，对我国茶树病原真菌和内生真菌群落进行系统研究，明确病原和内生真菌的物种分布及多样性；阐明内生真菌的分布规律及其与地理分布的相关性。收集大量菌株，为进一步开展新拮抗菌、新结构生物活性物质的筛选和其它生物学研究提供丰富的菌种资源。本项目在植物病害防治、农业可持续发展、内生真菌资源的开发利用等诸多领域都具有重要的科学意义。

对中国12省（广西、广东、云南、贵州、江西、河南、浙江、湖南、安徽、福建、西藏、四川）的57个茶树种植区进行了大规模的茶树病害调查和样本采集，以及健康组织样本的采集，共收集到植物标本1500余份，采用单孢分离和组织分离方法共分离获得茶树病原菌988株、内生菌279株。运用分子生物学和形态学观察相结合的方法，将病原菌和内生菌归为20目、38科、68属的162种。其中，优势病原菌包括刺盘孢属Colletotrichum (25.7%)、间座壳属Diaporthe (10.5%)、拟盘多毛孢属Pestalotiopsis (10.7%)、叶点霉属Phyllosticta (9.1%)、黑孢属Nigrospora (5%)等。进一步对上述几个类群进行多基因系统演化分析和形态学观察，结果显示，引起茶树相应病害的几大类病原菌并非单一物种，且广泛分布、不具备地理特异性。比如，引起茶树炭疽病的刺盘孢属真菌包括11种，引起叶斑病的间座壳属真菌9种和引起轮纹病的拟盘多毛孢属15种，几乎分布在每个采样地。正式发表新物种20个。主成分分析结果显示，我国江南（浙江、江西、安徽）、西南（云南、贵州）和华南（广西、广东、福建）三大茶区的茶树病原菌无明显的群落结构分化，江西（江南茶区）和云南（西南茶区）茶树内生菌的群落结构也无明显的分化。本研究揭示了茶树病原菌的极大多样性，将已知茶树病原菌的物种数量从280个上升至383个。获得的内生菌菌株将为进一步开展新拮抗菌、新结构生物活性物质的筛选提供丰富的菌种资源。