DISSERTATION RESEARCH: Phylogeny, Specificity, and Biogeography of Endophytic Xylariaceae in Liverworts

真菌内生菌是生长在活的植物体内的真菌，对宿主没有明显的伤害。 虽然内生菌已被发现在各种各样的植物，大多数内生关系的生态学仍然是未知的。 在世界各地的宿主植物的广泛多样性中，经常将炭角菌科中的真菌鉴定为内生菌，但几乎不知道它们是否是宿主特异性的，或者内生菌的特定物种在地理上如何分布。 本计画将著重于地钱内生真菌的生态学与遗传关系。由于植物内生真菌很难通过形态学进行鉴定，因此将采用分子生物学方法从DNA序列上对真菌进行鉴定。 初步研究表明，与许多其他植物一样，炭角菌科是地钱中占优势的内生菌。地钱是最早在陆地上定居的植物类群之一，大约在4亿年前，有人认为真菌有助于促进陆地生物进化中的这一重要步骤。内生菌将从北美、加勒比地区、南美、欧洲和新西兰收集的植物中培养。将通过其与已知真菌的相似性来鉴定来自内生菌的DNA序列;将与GenBank（国家生物技术信息中心）中包含的数据和杜克大学可获得的数据库进行比较。地理，生态和遗传信息将被整合，以使宿主特异性，地理结构，以及内生和非内生炭角菌科和其他真菌之间的关系的推断。该项目的完成将有助于培养一名博士生，并增加我们对全球真菌生物多样性的了解，也许可以揭示以前未描述的物种。 这项研究也将为未来的工作提供基础，旨在了解这种潜在的重要植物-真菌相互作用的生态学和进化。作为这项研究的结果获得的培养物将提交给美国典型组织收集，在那里他们可以访问其他科学家的未来实验和比较研究。

Fungal endophytes are fungi that grow inside living plants, causing no apparent harm to the host. Although endophytes have been revealed in a wide variety of plants, the ecology of most endophytic relationships remains unexplored. Fungi in the family Xylariaceae are regularly identified as endophytes in a broad diversity of host plants throughout the world, yet almost nothing is known about whether they are host specific, or how particular species of endophytes are distributed geographically. This project will focus on the ecology and genetic relationships of fungi living endophytically in liverworts. It is difficult to identify endophytic fungi based on morphology, so molecular methods will be used to identify the fungi from their DNA sequences. Preliminary research has shown that Xylariaceae are dominant endophytes in liverworts, as in many other plants. Liverworts comprise one of the earliest groups of plants to colonize land, some 400 million years ago, and it has been suggested that fungi helped to facilitate this important step in the evolution of terrestrial organisms. Endophytes will be cultured from plants collected in North America, the Caribbean region, South America, Europe, and New Zealand. DNA sequences from endophytes will be identified by their similarity to known fungi; comparisons will be made against data contained in GenBank (National Center for Biotechnology Information), and databases available at Duke University. Geographic, ecological, and genetic information will be integrated in order to make inferences about host specificity, geographic structure, and relationships within and among endophytic and non-endophytic Xylariaceae and other fungi. Completion of this project will contribute to training a doctoral student and increase our knowledge of global fungal biodiversity, perhaps revealing previously undescribed species. This research will also provide a foundation for future work aimed at understanding the ecology and evolution of this potentially important plant-fungus interaction. The cultures obtained as a result of this research will be submitted to the American Type Tissue Collection , where they can be accessed for future experimental and comparative studies by other scientists.