The broader impact/commercial potential of this Small Business Innovation Research (SBIR) project is the development of a probiotic that can replace up to $5B of chemical fertilizers used in domestic corn production. This novel probiotic would reduce water pollution from fertilizer runoff, lower greenhouse gas emissions, and conserve energy resources through lower production costs. Globally, this product could have an impact in regions like China and India where fertilizer demand outpaces available supply. This technology platform may be used to rapidly create new probiotics for other crops, and focus on applications beyond nitrogen fertilizer, in the future.<br/><br/>This SBIR Phase I project proposes to develop probiotic endophytes that provide fixed nitrogen to crops as an alternative to chemical fertilizers. Microbes silence genes for nitrogen fixation in response to fertilizer to conserve energy. This project aims to disrupt the genetic link between sensing fertilizer and microbial nitrogen fixation, so that a probiotic can produce nitrogen in fields today. This work will evaluate the persistence of evolved microbes in field soils while assessing formulation strategies that confer effective crop colonization and improved shelf life. If successful, this work will provide a foundation for routine development of fertilizers from plant endophytes. Further, these endophytes could serve as a model for understanding how microbes establish robust relationships with plants and the surrounding microbial community.