Nitrogen fertilizer increases crop yields to meet growing food demands, but because less than 50 percent of applied nitrogen fertilizer is used by plants, the excess fertilizer can threaten environmental and human health. Legume crops can create their own nitrogen through root nodule symbiosis with certain microbes. While research efforts are underway to engineer popular cereal crops to form root nodules, there is not a strong effort to generate a compatible microbial partner for these crops. This research is investigating root nodule symbiosis to develop microbes that can thrive in the cereal microbiome, initiate nodule formation and self-adapt for efficient nitrogen fixation and nutrient exchange with their host plant.