In nature, organisms often work together in mutually beneficial ways. However, while theory predicts these beneficial relationships reduce variation in both partners, real-world evidence often contradicts this, especially for bacteria that can thrive with or without plant hosts. This project investigates whether plant host presence over time and space helps maintain bacterial variation. The focus is on an ecologically, agriculturally, and economically important interaction between leguminous plants and their mutualistic bacteria, which convert atmospheric nitrogen into a usable form inside structures on plant roots called nodules. This proposal will benefit agricultural production and ecological conservation, prepare the future scientific and agricultural workforce, and connect students at multiple educational levels with ecological and evolutionary concepts, as well as artificial intelligence-enabled image, statistical, and modeling analysis tools. The nitrogen-fixing symbiosis studied here is one of the most ecologically, agriculturally, and economically important plant-bacteria symbioses. Understanding the host drivers of bacterial variation will inform better decision-making in agriculture and restoration projects, boosting the effectiveness of nitrogen-fixing bacteria, which are crucial for eco-friendly farming. Educational programs will develop curricula that foster project-based learning in Pennsylvania high schools through a “Community Symbiosis Curriculum” aligned with new science standards and in undergraduate plant science courses with plant distribution models to build quantitative and computational skills. This initiative supports workforce development by offering hands-on training with educational experts and creating near-peer mentors for high school students, inspiring more young people to pursue careers in agriculture and biotechnology. In nature, organisms interact in complex ways. This project examines mutualism, where both organisms benefit, a