When the host is the ecosystem: linking presence of a keystone fungal symbiont to mycobiome structure and function in a changing world

植物被各种微观真菌定殖，这些真菌可以促进植物生长，保护植物免受疾病或害虫的侵害，并帮助植物耐受压力环境。虽然许多种类的真菌在植物体内共同生活，但科学家们仍在试图了解不同类型的真菌如何相互作用，这些相互作用如何影响植物，以及这些真菌相互作用是否可以被操纵以帮助植物在不断变化的世界中茁壮成长。这项研究将使用强大的遗传和数学工具来调查生活在五大湖地区常见的沙丘建筑植物美国滨草的叶子和根部的真菌。研究人员将研究真菌如何在植物内部相互作用，导致植物宿主发生物理和化学变化，从而影响植物的生存。此外，研究人员还将测试环境变化（如空气污染增加）是否会影响这些相互作用的性质。这项研究将为生活在植物内部的微生物的复杂世界提供重要的见解，并对沙丘和沿海生态系统的栖息地恢复产生影响，这对美国的经济和环境健康至关重要。最后，该项目将为下一代科学家提供培训。研究人员将启动“生物桥”计划，这是一个基于实地的经验，将为历史上被排斥和社会经济地位较低的生物学学生的成功奠定基础，同时建立社区和科学的归属感。这项研究的中心假设是，（Epichloë）通过改变宿主植物的化学和物理性状，作为基础沙丘草物种（Ammophila）的关键真菌生物群系工程师，对宿主和宏观生态系统功能产生级联影响。首先，将使用元条形码方法调查与Epichloë感染和未感染的Ammophila相关的叶和根内生真菌和丛枝菌根真菌。将建立生态网络，使地上地下物种相互作用的背景化，并对Epichloë如何通过网络结构的变化来改变多物种相互作用进行预测性理解。第二，一个长期的氮沉降实验将测试资源的可用性和Epichloë的殖民化影响Ammophila菌群的机制。物理和化学主机性状将被测量和用于构建结构方程模型，研究化学和物理植物性状之间的关系。最后，生长室实验将与田间实验相结合，以测试与Epichloë存在相关的真菌生物群系的变化是否直接导致Ammophila存活和生长的改善。这项工作将对沙丘和沿海生态系统的栖息地恢复产生影响，这对美国的经济和环境健康至关重要。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Plants are colonized by diverse microscopic fungi that can improve plant growth, protect plants from diseases or pests, and help plants tolerate stressful environments. While many kinds of fungi live together inside of plants, scientists are still trying to understand how different types of fungi interact, how those interactions affect plants, and whether these fungal interactions can be manipulated to help plants thrive in a changing world. This research will use powerful genetic and mathematical tools to investigate fungi living in the leaves and roots of the common dune-building plant, American Beachgrass, in the Great Lakes region. The researchers will examine how fungi interact inside plants to cause physical and chemical changes to the plant host, which can affect plant survival. Additionally, the researchers will test if environmental changes such as increased air pollution will affect the nature of these interactions. The research will provide crucial insights into the complex world of microorganisms living inside plants, and has implications for habitat restoration in dune and coastal ecosystems, which are critical to the economic and environmental health of the United States. Finally, this project will provide training to the next generation of scientists. The researchers will launch the “BioBridge” program, a field-based experience that will provide a foundation for the success of historically excluded and lower socioeconomic status biology students, while building community and a sense of belonging in the sciences.The central hypothesis of this research is that a vertically-transmitted endophyte (Epichloë) acts as a keystone mycobiome engineer of a foundational dune grass species (Ammophila) by modifying host plant chemical and physical traits, with cascading implications for host and macro-ecosystem function. First, a metabarcoding approach will be used to survey the leaf and root fungal endophytes and arbuscular mycorrhizal fungi associated with Epichloë-infected and uninfected Ammophila. Ecological networks will be built to contextualize aboveground-belowground species interactions and develop a predictive understanding of how Epichloë modifies multispecies interactions via changes to network structure. Second, a long-term nitrogen deposition experiment will test the mechanisms by which resource availability and colonization by Epichloë affect the Ammophila mycobiome. Physical and chemical host traits will be measured and used to construct structural equation models that examine relationships among chemical and physical plant traits. Finally, a growth chamber experiment will be coupled with a field experiment to test whether changes to the mycobiome associated with Epichloë presence are directly responsible for improved Ammophila survival and growth. This work will have implications for habitat restoration in dune and coastal ecosystems, which are critical to the economic and environmental health of the United States.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.