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

气候模型预测未来气温更高，降水量变化更大，极端天气事件也更多。在这种变化的环境下，基础植物物种可以促进其他物种的稳定条件，支持基本的生态系统过程，可能会受益于微生物伙伴，这些合作伙伴可以在极端气候下提高植物的生存能力。然而，微生物伙伴是否能够帮助缓冲生态系统免受气候变化的影响仍是个未知数。这项研究调查了一组广泛存在但鲜为人知的真菌，这些真菌通常生长在优势牧草的根部。该项目确定了这些真菌的益处如何随着干旱和高温胁迫的梯度而变化，在不同草种之间的差异，以及在不同地理区域之间的变化。这项工作在识别帮助植物在紧张的气候中生存和生长的真菌方面前景光明。这个团队将共同将研究活动整合到一个新的高中教师培训计划中，该计划侧重于服务不足的社区和一套中学研讨会的实验室模块。研究结果将揭示微生物伙伴在维持草原和牧场生产力方面的作用，提高在未来气候中保护、管理和恢复这些重要地区的能力。对根内生植物生物学的深入了解有可能改变人们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得养分的范式一样。该项目测试了根伴生真菌是否有利于优势草原植物物种，这可能会缓解干旱和热浪期间净初级生产力的损失。这项工作解决了以下问题：(1)寄主物种特性与地理和气候梯度在解释共生菌丰度和组成变化方面的相对重要性是什么？(2)寄主物种特性和地理来源对高温和干旱胁迫梯度的共生体效益的影响有多大？(3)共生体介导的胁迫改善能否从实验室环境中推广出来，以预测田间结果？活动包括沿纬度梯度的实地调查、新一代根真菌高通量测序、大型真菌培养集合的开发、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地点降雨试验的实地试验。该项目的新方面包括：沿着纬度梯度表征与根相关的真菌组成，检验共生体在非生物胁迫增加时对植物更有利的假说，以及确定田间条件下内生根真菌如何影响植物寄主。

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.