DISSERTATION RESEARCH: The role of resource mutualisms in plant adaptation to abiotic environments

植物可以通过分散到压力较小的栖息地来克服环境压力，适应压力，或与其他生物（如微生物）结合，帮助减轻压力。尽管第三种应对压力的策略很少受到关注，但越来越多的证据表明，它既普遍又有效。被称为根瘤菌的土壤细菌就像天然肥料一样，将大气中的氮转化为至少一些植物可以利用的形式。作为回报，这些植物为根瘤菌提供能量。本研究的目的是确定根瘤菌是否有助于植物在极端水分胁迫下生存。这项研究很重要，因为在全球气候变化的影响下，预计世界大部分地区的干旱压力会增加，而根瘤菌是植物克服这种压力的最有可能的方式之一。这具有实际意义。例如，了解植物与根瘤菌的伙伴关系可能有助于减少农业系统中合成肥料的施用或不必要的用水。研究结果将通过在国家和区域会议、高中课堂以及自然学家和土地管理者的通讯上的报告广泛分享。研究人员还将为高中生创建和发布基于探究的活动，这些活动与大学先修课程（AP）生物学课程相一致。具体而言，本研究将探讨资源互惠主义者如何影响植物对土壤水分的适应。利用豆科植物与根瘤菌的共生关系作为模型系统，研究人员旨在扩大对当地适应机制的理解，物种相互作用如何影响当地适应，以及适应的基本特征。将解决三个具体问题：(1)植物是否适应当地的土壤湿度条件？(2)资源共生是否有助于植物对土壤水分的适应？(3)哪些植物性状驱动植物适应潮湿和干燥环境？这些问题将通过在不同土壤湿度的多个地点进行一套完整的互惠移植实验、操纵温室实验和分子分析来解决。

Plants can overcome environmental stress by dispersing to less stressful habitats, adapting to the stress, or associating with other organisms, such as microbes, that help reduce the stress. Although the third strategy of coping with stress has received very little attention, there is increasing evidence that it is both common and effective. Soil bacteria called rhizobia act like natural fertilizer by converting nitrogen in the atmosphere into a form that at least some plants can use. In return, those plants provide energy to the rhizobia. The goal of this study is to determine whether rhizobia help plants survive under extreme water stress. This research is important because increasing drought stress is predicted for much of the world under global climate change and rhizobia are one of the most likely ways that plants may overcome that stress. This has practical implications. For example, understanding the plant-rhizobium partnership may help reduce application of synthetic fertilizers or unnecessary use of water in agriculture systems. Results will be shared broadly through presentations at national and regional meetings as well as in high school classrooms and in newsletters for naturalists and land managers. The researchers will also create and publish inquiry-based activities for high school students that are aligned with the Advanced Placement (AP) biology Curriculum. Specifically, this research will investigate how resource mutualists influence plant adaptation to soil moisture in the field. Using the legume-rhizobia mutualism as a model system, investigators aim to expand understanding of the mechanisms contributing to local adaptation, how species interactions influence local adaptation, and the traits underlying adaptation. Three specific questions will be addressed: (1) Are plants locally adapted to soil moisture conditions? (2) Do resource mutualists contribute to plant adaptation to soil moisture? And, (3) what plant traits drive adaptation to wet vs. dry environments? These questions will be tackled with an integrated set of reciprocal transplant experiments across multiple sites differing in soil moisture, with manipulative greenhouse experiments, and with molecular analyses.