DISSERTATION RESEARCH: Investigating life history and environmental drivers structuring host-associated assemblages of mycorrhizal and endophytic fungi in subalpine tree islands

在DNA测序技术取得最新进展之前，科学家们永远无法想象与每一种植物和动物相关的巨大微生物多样性。所有高等生物都是微生物和真菌的不同联合体的家园，而不是单个离散的生物体，这些微生物被称为微生物。从我们的嘴巴到植物的叶子，独特的微生物群落对高等生物的功能发挥着重要的作用。这项研究的重点是了解植物叶片相关真菌(叶内生真菌)和树木根部有益真菌(外生菌根真菌)群落结构的驱动机制。这项研究通过揭示真菌多样性具有广泛的社会影响，有助于改善树木健康、生态系统稳定性和对气候变化的适应能力。白皮松是本研究的重点树种之一，是亚高山环境中生态系统功能的核心基础树种。白皮松树受到水泡锈病、山松甲虫和气候变化的高度威胁。众所周知，叶面内生植物可以提高树木对气候变化引起的疾病和温度波动的抵抗力。因此，发现与这些树相关的叶内生植物的多样性有可能导致对这种濒危树种的有益治疗。此外，该项目还具有强大的教育和宣传内容。参与这项拟议工作的学生将获得实地工作和尖端DNA测序方法的经验。尽管这些真菌是植物群落组成和生态系统功能的极其重要的驱动力，但人们对这些真菌的基本生物学或多样性模式知之甚少。该项目将尖端的下一代测序技术应用于约塞米蒂国家公园的松树，以回答有关这些真菌的群落结构、多样性和基本生物学的重要问题。在这里，一个简单的寄主-岛屿设置被用来测试扩散距离、寄主类型、环境(寄主生理、土壤化学和季节)对两个寄主依赖的真菌协会的群落结构的影响。这项建议的主要目的是比较寄主相关真菌的两个功能行会中生态位组装和分散组装的相对效果。

Prior to recent advances in DNA sequencing technologies, scientists could never have imagined the vast microbial diversity associated with each individual plant and animal. Rather than individual discrete organisms, all higher organisms are home to diverse consortia of microscopic bacteria and fungi, called microbes. From our mouths to plants' leaves, unique communities of microorganisms play important roles in higher organisms'ability to function. This research focuses on understanding the mechanisms driving the community structure of the fungi associated with the leaves of plants (foliar endophytes) and beneficial fungi associated with the roots of trees (ectomycorrhizal fungi). This research has broad ranging societal impacts by uncovering fungal diversity that can be helpful to improving tree health, ecosystem stability, and resilience to climate change. One of the focal trees in this study, the white bark pine, is a foundation species central to ecosystem function in subalpine environments. White bark pine trees are highly threatened by a combination of blister rust, mountain pine beetles, and climate change. Foliar endophytes are known to improve the resistance of trees to both disease and temperature fluctuations caused by climate change. Thus, uncovering the diversity of foliar endophytes associated with these trees has the potential to lead to beneficial treatments for this endangered tree species. In addition, this project also has strong educational and outreach components. Students involved in the proposed work will gain experience with fieldwork and cutting edge DNA sequencing methods. Despite being incredibly important drivers of plant community composition and ecosystem function, little is known about the basic biology or patterns of diversity of these fungi. This project applies cutting edge next generation sequencing technologies to isolated pine trees located in Yosemite National Park to answer important questions about the community structure, diversity, and basic biology of these fungi. Here a simple host-island setting is used to test for the effect of dispersal distance, host type, environment (host physiology, soil chemistry & season), on community structure in two host-dependent guilds of fungi. The main aim of this proposal is to compare the relative effects of niche versus dispersal assembly in two functional guilds of host-associated fungi.