DISSERTATION RESEARCH: Early Evolution of Fungi and the Transition to a Terrestrial Lifestyle: Marine Habitats, the New Frontier

游动孢子真菌(通过可移动的孢子繁殖的真菌)代表了真菌生命树中最早的谱系；不幸的是，它们也是最鲜为人知的。这些真菌的样本有限，特别是来自海洋和河口生境的样本，限制了重建真菌王国早期进化的尝试。全面揭示游动孢子真菌多样性的主要障碍是历史上依赖培养的方法，导致只描述最丰富的类群，或者那些适合在实验室分离的类群。最近使用独立于培养的分子方法来表征陆地、淡水和极端环境中的真菌多样性和群落组成，揭示了新的早期发散的真菌谱系。此外，这些研究还发现，游动孢子真菌谱系往往是各自生态系统中的主要真菌成分。由于环境克隆研究具有较高的时间和供应成本，下一代测序已被推广为一种快速、经济有效的方法，用于表征以前被忽视的生境中的隐蔽微生物群落。现在有几个元基因组分析管道和参考数据库，以协助对从环境样品中恢复的分子序列进行分类和分类鉴定。然而，现有数据库中的大量序列来自以前的环境克隆研究，超出了系统发育框架，没有相应的分类，阻碍了对鲜为人知的群体进行分类的努力。为了解决这些问题，本文提出的研究旨在：1)使用非培养方法发现新的海洋真菌分类群；2)推断这些分类群与所有已知的游动孢子类群的系统发育关系，主要包括陆生和淡水真菌；和3)使用为目标2产生的系统发育数据集来确定真菌鞭毛的丢失日期，并估计在真菌进化中采用主要陆地生活方式的最小年龄(S)。拟议的研究将为积极的本科生提供培训，除了为两个当地科学博物馆(北卡罗来纳州生命与科学博物馆，北卡罗来纳州达勒姆；北卡罗来纳州自然科学博物馆，罗利市)提供以儿童为重点的真菌互动展览及其与植物和动物的共生互动的信息。

Zoosporic fungi (fungi that reproduce through motile spores) represent the earliest lineages in the fungal tree of life; unfortunately, they are also the most poorly understood. Limited sampling of these fungi, especially from marine and estuarine habitats, constrains attempts to reconstruct the early evolution of the kingdom Fungi. The primary hindrance to uncovering the full extent of zoosporic fungal diversity is the historical reliance on culture-dependent methods, resulting in the description of only the most abundant taxa, or those amenable to isolation in the laboratory. The recent use of culture-independent molecular methods to characterize fungal diversity and community composition in terrestrial, freshwater, and extreme environments has revealed novel early-diverging fungal lineages. Additionally, these studies have found that zoosporic fungal lineages are often the dominant fungal component of their respective ecosystems. As environmental cloning studies have high time and supply costs, next-generation sequencing has been promoted as a rapid, cost-effective method for characterizing communities of cryptic microorganisms in previously neglected habitats. Several metagenomic analysis pipelines and reference databases now exist to assist in the clustering and taxonomic identification of molecular sequences recovered from environmental samples. However, the available databases are populated with large numbers of sequences from previous environmental cloning studies outside a phylogenetic framework and without a corresponding taxonomic classification, hindering efforts to classify poorly known groups. To address these issues, the research proposed herein aims to: 1) use culture-independent methods to discover novel marine fungal taxa; 2) infer the phylogenetic relationships of these taxa with all known zoosporic counterparts, consisting primarily of terrestrial and freshwater fungi; and 3) use the phylogenetic dataset produced for objective 2 to date the loss(es) of the fungal flagellum and estimate the minimum age(s) of the adoption of a primarily terrestrial lifestyle in the evolution of the Fungi.The proposed research will provide training for a motivated undergraduate student, in addition to informing the development of child-focused interactive exhibits on fungi and their symbiotic interactions with plants and animals for two local science museums (North Carolina Museum of Life and Science, Durham, NC; North Carolina Museum of Natural Sciences, Raleigh, NC).