COLLABORATIVE RESEARCH: Parsing the effects of host specificity and geography on plant-fungal symbioses under climate change

气候模式预测未来气温升高、降水变化更大、极端天气事件更多。在这种变化的环境下，促进其他物种稳定条件和支持基础生态系统过程的基础植物物种可能受益于微生物伙伴，这些微生物伙伴可以提高植物在极端气候下的生存能力。然而，微生物伙伴是否能够帮助生态系统抵御气候变化仍然未知。这项研究调查了一种广泛存在但鲜为人知的真菌，它们通常生长在主要牧草的根部。该项目确定了这些真菌的益处如何沿着干旱和热胁迫的梯度变化，不同草种之间的差异以及跨地理区域的变化。这项工作对识别帮助植物在压力气候下生存和生长的真菌有很大的希望。这个团队将把研究活动整合到一个新的高中教师培训计划中，该计划将重点放在服务欠缺的社区，并为中学讲习班提供一套实验室模块。研究结果将揭示微生物伴侣在维持草地和牧场生产力，提高在未来气候条件下保护、管理和恢复这些重要地区的能力方面的新功能。对根内生菌生物学的深入了解有可能改变对植物如何应对干旱和高温的理解，就像对菌根真菌的研究颠覆了植物如何获取营养的范式一样。该项目测试根系相关真菌是否有利于优势草原植物物种，这可能会减缓干旱和热浪期间净初级产量的损失。这项工作解决了以下问题：(1)在解释共生丰度和组成的变化时，宿主物种身份与地理和气候梯度的相对重要性是什么？(2)寄主物种身份和地理来源对高温和干旱胁迫梯度下共生体效益的影响有多大？(3)共生介导的应激改善能否从实验室环境推广到现场预测结果？活动包括沿纬度梯度的实地调查，下一代根真菌的高通量测序，大型真菌培养收集的开发，操纵干旱和高温的多因素温室试验，以及利用现有的大型跨站点降雨试验的实地试验。该项目的新方面包括沿纬度梯度表征根相关真菌组成，验证共生在增加的非生物胁迫下对植物更有利的假设，以及确定内生根真菌在田间条件下如何影响植物宿主。

Climate models project higher temperatures, more variability in precipitation, and more extreme weather events in the future. Under such changing environments, foundation plant species, which promote stable conditions for other species and support fundamental ecosystem processes, may benefit from microbial partners that enhance plant survival during climate extremes. However, whether microbial partners can help buffer ecosystems against climate change remains unknown. This research investigates a widespread, but poorly known, group of fungi that commonly grow in the roots of dominant forage grasses. The project determines how the benefits of these fungi vary along gradients of drought and heat stress, differ among grass species, and shift across geographic regions. This work has high promise for identifying fungi that help plants survive and grow in stressful climates. Together, this team will integrate research activities into a new high school teacher training program that focuses on underserved communities and a set of laboratory modules for middle school workshops. Results will shed new light on the functions of microbial partners in maintaining grassland and rangeland productivity, improving the ability to conserve, manage, and restore these important areas in future climates.Deeper insight into the biology of root endophytes has the potential to transform understanding of how plants respond to drought and heat in the same way that studies on mycorrhizal fungi overturned paradigms about how plants acquire nutrients. This project tests whether root-associated fungi benefit dominant grassland plant species, which may moderate the loss of net primary production during droughts and heat waves. The work addresses the following questions: (1) What is the relative importance of host species identity versus geographic and climatic gradients in explaining variation in symbiont abundance and composition? (2) How strongly do host species identity and geographic origin influence the magnitude of symbiont benefits across gradients of heat and drought stress? (3) Can symbiont-mediated amelioration of stress be generalized from laboratory settings to predict outcomes in the field? Activities include field surveys along latitudinal gradients, next-generation high-throughput sequencing of root fungi, development of a large fungal culture collection, multi-factor greenhouse trials that manipulate drought and heat, and field tests that leverage existing, large, cross-site rainfall experiments. Novel aspects of this project include characterizing root-associated fungal composition along latitudinal gradients, testing the hypothesis that symbioses become more beneficial to plants under increased abiotic stress, and determining how endophytic root fungi affect plant hosts under field conditions.