CAREER:Novel interactions in novel conditions: consequences of disrupting historical plant-fungal interactions for tree responses to environmental variation

当一个植物物种在一个地区受到气候变暖或干燥的压力时，它有三种选择：迁移到一个具有合适气候的新地点，通过进化或驯化来适应新的气候，或者在该地区灭绝。然而，我们现在知道，所有植物都与高度多样的微生物（即真菌）群落相关联，这可以帮助植物获得土壤中的水分和养分。这项研究将调查树种是否可以利用真菌与他们的根区，以增加他们的耐受性干燥条件。这项研究还将测试破坏植物和与其根部相关的真菌之间的历史关系，是否会对在新地区建立的树苗有益或有害。此外，该项目将建立一个公民科学家网络，帮助收集美国东部几个树种的根系样本。然后，这些样本将用于一门新的本科课程，学生们将使用新兴的分子生物学和计算工具来识别和绘制森林土壤中真菌物种的当前分布。总之，这些新知识可能有助于预测温带森林将如何应对不断变化的环境，并可能导致新的工具，通过保护或操纵土壤微生物来促进森林健康。对于植物来说，根部及其周围的微生物群落可以调节土壤水分和养分的获取。这些社区的改变可能提供了一个替代来源的植物耐环境变化的表型变异。由于植物和微生物种群都改变了它们的分布，植物种群、微生物类群和非生物条件之间的历史关系将被破坏。该项目将研究新的植物-微生物相互作用如何影响当前范围内和范围外的树木建立。为了实现这一目标，研究人员将使用在现场和控制设置，操纵树苗源人口和土壤微生物群落，沿着和根际真菌群落的分子特征的实验相结合。具体而言，该项目将1）确定树木种群是否适应当地微生物群落，以及如何将其与适应气候和土壤梯度进行比较，2）测试根相关微生物群落是否在面对不断变化的环境时介导范围扩张和收缩，以及3）记录根际微生物类群目前如何在宿主范围内分布，以及这些分布在快速的环境变化下如何变化。

When a plant species is stressed by warming or drying climates in an area it has three options: move to a new location that has a suitable climate, develop tolerance to the new climate through evolution or acclimation, or go extinct in the area. However, we now know that all plants exist in association with a highly diverse community of microorganisms (i.e. fungi), which can help plants access water and nutrients in soil. This research will investigate whether tree species can utilize the fungi associated with their root zones to increase their tolerance to drying conditions. The study will also test whether disrupting the historical relationships between plants and the fungi associated with their roots, will benefit or harm tree seedlings as they establish in new areas. Additionally, this project will establish a network of citizen scientists who will aid in collecting root samples from several tree species across the eastern United States. These samples will then be used in a new undergraduate course in which the students use emerging molecular biology and computational tools to identify and map the current distribution of fungal species in forest soils. Together, this new knowledge may help predict how temperate forests will respond to changing environments, and potentially lead to new tools to promote forest health by conserving or manipulating soil microbes. For plants, microbial communities in and around roots can mediate access to soil moisture and nutrients. Alterations of these communities may provide an alternative source of phenotypic variation in plant tolerance to environmental changes. As both plant and microbial populations shift their distributions, historical relationships between plant populations, microbial taxa, and abiotic conditions will be disrupted. This project will investigate how novel plant-microbial interactions may affect tree establishment within and beyond current ranges. To accomplish this, the investigator will use a combination of experiments in the field and controlled settings which manipulate tree seedling source population and soil microbial communities, along with and molecular characterization of rhizosphere fungal communities. Specifically, the project will 1) determine whether tree populations are adapted to local microbial communities, and how this compares with adaptation to climatic and edaphic gradients, 2) test whether root-associated microbial communities mediate range expansion and contraction in the face of changing environments, and 3) document how rhizosphere microbial taxa are currently distributed across host ranges, and how these distributions may shift under rapid environmental changes.