Potential roles of iron nanomaterials in enhancing growth and nitrogen fixation and modulating rhizomicrobiome in alfalfa (Medicago sativa L.)

Iron (Fe) is one of the essential nutrient elements for plant growth and development. However, the potential roles of iron nanomaterials in regulating growth and nitrogen fixation and modulating rhizomicrobiome in legume plants are poorly known. In this study, we reported that 10 mg L-1 is the optimal concentration for the application of iron nanoparticles (FeNPs) and seed soaking plus leaf spraying is the optimal application method of FeNPs in alfalfa (Medicago sativa L.); FeNPs had more positive effects on the growth and nitrogen fixation capability in alfalfa than FeCl2; FeNPs enhanced the intensity of corporations and competitions among rhizosphere fungal taxa of alfalfa. This work provides insights into the regulation mechanism of FeNPs on growth, nitrogen fixation, and the composition and function of rhizosphere microbial community in legume plants as well as the potential application value of FeNPs in agriculture system.