Dissertation Research: Partner Variability and Fitness in a Legume-Rhizobium Mutualism

生物互惠是物种之间的相互作用，其中两个物种都受益。 这些相互作用在自然界中无处不在。 这些互惠关系中研究得最好且具有经济重要性的一种发生在豆科植物和根瘤菌之间，在这种互惠关系中，植物为细菌提供食物和庇护所，而细菌为植物提供氮。 然而，人们对维持这些伙伴之间合作的进化力量知之甚少。 本项目将研究模式植物蒺藜苜蓿与共生菌苜蓿中华根瘤菌之间的协同进化。 操纵温室实验将用于研究共生对双方繁殖成功的影响。 这些数据将使我们能够确定互惠是否对双方都有利，或者在有益和寄生之间波动。这项研究将推进我们对互惠在自然界中如何进化的认识，并有助于理解基本的进化过程。 这些知识将提高我们管理互惠互动的能力，因为它们通常在作物生产和生态系统恢复中发挥重要作用。 此外，深入了解这些关系将提高我们的理解的影响，自然和人为的环境条件的变化对互惠稳定。

Biological mutualisms are interactions between species in which both species benefit. These interactions are ubiquitous in nature. One of the best studied and economically important of these mutualisms occurs between legume plants and rhizobial bacteria, a mutualism in which plants provide food and shelter to the bacteria and the bacteria provide nitrogen to the plant. Little is known, however, about the evolutionary forces that maintain cooperation between these partners. This project will investigate coevolution between the model plant Medicago truncatula and its symbiotic bacterium Sinorhizobium meliloti. Manipulative greenhouse experiments will be used to study the effects of symbiosis on the reproductive success of both partners. These data will allow us to determine if mutualisms are optimally beneficial for both parties or fluctuate between being beneficial and parasitic.This research will advance our knowledge of how mutualisms evolve in nature as well as contribute to an understanding of basic evolutionary processes. This knowledge will increase our ability to manage mutualistic interactions, as they often play important roles in both crop production and ecosystem restoration. Moreover, insight into these relationships will improve our understanding of the effects natural and anthropogenic changes in environmental conditions have on mutualism stability.