EAGER: Plant-microbe interactions in a changing world: indirect effects of environmental change in a heterogeneous landscape

环境变化对植物有直接影响，因为植物的生长取决于氮、温度和干旱等因素。然而，环境变化也可能产生“间接影响”，通过改变共生物种的丰富度，对正在研究的植物产生积极或消极的影响。虽然通过植物竞争对手和动物食草动物产生的间接影响已经得到了很好的研究，但通过微生物(包括真菌和细菌)产生的间接影响却很少受到关注。大量的微生物存在于所有的植物中，它们有各种各样的影响：一些微生物会导致疾病，而另一些微生物则是有益的，并促进植物健康。环境变化可能会改变致病或有益微生物的数量，这将通过间接影响对植物生长产生影响。该项目将评估落基山脉高山冻土带环境变化、微生物和植物之间的联系。更深入地了解微生物将如何受到环境条件变化的影响，以及对未来植物生长的影响，对于管理我们的自然资源非常重要。在落基山脉尤其如此，这是一个备受欢迎的旅游目的地，支持着许多野生动物。这项工作还可能导致识别未来可能增加的植物疾病，或者可能对恢复有用的有益微生物。为了测试环境变化如何影响微生物群落和植物生长，研究人员将在以下方面测量植物的表现(生长、花朵生产)以及微生物丰度和多样性(土壤和植物根部)：1)对高山冻土带不同环境的实地调查，包括凉爽/潮湿到温暖/干燥条件；2)操纵生长季节长度和温度的田间实验。通径分析将被用来评估环境变化对植物表现的直接影响和间接影响。这项调查和实验在阿尔卑斯山的一系列环境条件下重复进行，以评估间接影响的强度和方向是否在不同的地形上有所不同。为了了解改变微生物群落组成和多样性的机制，研究人员将在调查和实验中测量非生物(例如土壤水分、雪深)和生物(例如植物胁迫)因素，并将它们与微生物群落结构联系起来。通过使用现有数据库将微生物分类为病原体、互助者或分解者，并使用基于培养的实验室接种实验测量一些微生物分类群的功能，将探索该系统中重要微生物参与者的功能。该奖项反映了NSF的法定使命，并已通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Environmental change has direct impacts on plants since plant growth depends on factors like nitrogen, temperature, and drought. However, environmental change can also have “indirect effects”, by altering the abundance of co-occurring species that either positively or negatively affect the plant being studied. While indirect effects through plant competitors and animal herbivores have been well studied, indirect effects via microbes (including fungi and bacteria) have received little attention. A vast array of microbes inhabits all plants, and they have a variety of effects: some microbes cause disease while others are beneficial and promote plant health. Environmental change may alter the amount of disease-causing or beneficial microbes, which will have consequences for plant growth via indirect effects. This project will assess linkages among environmental change, microbes, and plants in the alpine tundra in the Rocky Mountains. A deeper understanding of how microbes will be affected by changing environmental conditions, and implications for plant growth in the future, is important for managing our natural resources. This is especially true in the Rocky Mountains, a much-loved tourist destination that supports a lot of wildlife. This work may also lead to identification of plant diseases that may increase in the future, or beneficial microbes that may be useful for restoration. This project includes training opportunities for graduate and undergraduate students as well as outreach to middle school students and teachers.To test how environmental change may influence microbial communities and plant growth, the researchers will measure plant performance (growth, flower production) and microbes abundance and diversity (in soil and plant roots) in: 1) a field survey across different environments in the alpine tundra encompassing cool/wet to warm/dry conditions and 2) a field-based experiment that manipulates growing season length and temperature. Path analysis will be used to evaluate direct vs. indirect effects of environmental change on plant performance. The survey and experiment are replicated across a range of environmental conditions in the alpine in order to assess whether the strength and direction of indirect effects vary across a heterogeneous landscape. To understand mechanisms that alter microbial community composition and diversity, the researchers will measure abiotic (e.g., soil moisture, snow depth) and biotic (e.g., plant stress) factors in the survey and experiment and relate them to microbial community structure. Functions of important microbial players in this system will be explored by classifying microbes as pathogen, mutualist, or decomposer using existing databases, and by measuring the function of some microbial taxa using culture-based lab inoculation experiments.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.