RAPID: From microbes to new tropical forests: an experimental test of fungal specialization on host tree genotypes in the context of a reforestation experiment

土壤真菌被认为是热带树木育苗最重要的因素之一。致病的土壤真菌可以导致幼苗死亡，而其他土壤真菌与幼苗形成有益的共生关系，通过获得土壤中的关键养分来帮助它们茁壮成长。该项目的目标是在重新造林项目的背景下，更好地了解真菌促进树苗生长和保持树种多样性的背景。成年树之间的关联度将是这项工作的一个特别重点，假设当幼苗种植在与自身基因更不同的成年树附近时，它们将与更有益的真菌相互作用。该项目将在厄瓜多尔进行，厄瓜多尔是一个物种丰富的地区，面临着日益严重的森林砍伐威胁，这会向大气中释放碳。相比之下，重新造林为许多濒危物种创造了一个碳汇和栖息地。这项关于苗木-真菌相互作用的研究可以帮助设计重新造林的努力。更广泛的影响还包括培养一名美国博士后助理和研究生。该项目提供了一种新颖的多物种测试，通过对更常见的基因类型进行选择，并有利于更稀有的基因类型的生存，致病土壤真菌的种内专门化促进和维持植物物种内的遗传多样性。同时，研究还探讨了土壤真菌群落是否以及在什么情况下对苗木产生积极影响。为了做到这一点，该团队将实施一项荫棚实验，这是由厄瓜多尔的一个大规模重新造林项目实现的。研究设计允许评估苗木的表现，作为给定苗木的母体树与种植苗木的土壤的同种树的关联程度的函数。该设计允许36个种内配对比较，每个重复8个，分别针对16个不同的树种，以及灭菌接种剂的对照。树木的遗传亲缘关系以及真菌群落组成和功能的概况将通过高通量测序进行评估。这项工作有望提供新的数据，说明土壤真菌在多大程度上发生种内专化；同种母树之间的遗传相似性在多大程度上预测了土壤真菌对苗木表现的影响的大小和方向；以及土壤和根部真菌群落的具体组合如何影响苗木表现。这些发现有望促进我们对控制热带树木多样性的生态和微进化因素的理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Soil fungi are thought to be one of the most important factors for establishment of tropical tree seedlings. Pathogenic soil fungi can cause seedlings to die while other soil fungi form beneficial symbiosis with seedlings that can help them thrive by obtaining key nutrients in the soil. The goal of this project is to better understand the contexts in which fungi promote seedling growth and maintain tree species diversity, in the context of a reforestation project. Degree of relatedness between adult trees will be a particular focus of this work, with the hypothesis that seedlings will interact with more beneficial fungi when they are planted near adult trees that are more genetically different from themselves. This project will take place in Ecuador, in a species-rich region that is increasingly threatened with deforestation, which releases carbon into the atmosphere. Reforestation, in contrast, creates a sink for carbon and habitat for many endangered species. This research on seedling-fungal interactions can aid in designing reforestation efforts. The broader impacts further include training a U.S. based post-doctoral associate and graduate student.This project provides a novel, multi-species test of the idea that, by selecting against more common genotypes and favoring survival of rarer genotypes, within-species specialization by pathogenic soil fungi promotes and maintains genetic diversity within plant species. At the same time, the research also explores whether and in what contexts soil fungal communities have positive impacts on seedlings. To do so, the team will implement a shade house experiment made possible by a large-scale reforestation project in Ecuador. The study design allows an assessment of seedling performance as a function of how related a given seedling’s maternal tree is to the conspecific tree in whose soil the seedling is planted. The design allows 36 within-species pairwise comparisons with 8 replicates each, for each of 16 different tree species, as well as controls with sterilized inoculum. Genetic relatedness of trees and profiles of fungal community composition and function will be assessed via high-throughput sequencing. This work is expected to provide novel data on the extent to which within-species specialization by soil fungi occurs; the degree to which genetic similarity between conspecific maternal trees predicts magnitude and direction of soil fungal impacts on seedling performance; and how specific combinations of soil and root fungal communities impact seedling performance. These findings are expected to advance our understanding of the ecological and microevolutionary factors that control the diversity of tropical treesThis 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.