The promotion of legume nodulation in plant-soil-microbe systems under phosphorus-limited conditions

Background Legume plants can establish symbiotic interactions with rhizobia to form nodules, in which atmosphere dinitrogen (N ) is reduced to ammonium (NH) as a nitrogen (N) source for legume plants. This process is called biological nitrogen fixation (BNF). It is widely believed that BNF in legumes is phosphorus (P)-demanding and might be limited by P availability. Scope Here, we first discuss the overlooked role of plant P-acquisition/-use strategies in maintaining legume nodulation and BNF, then summarize the identified genes or regulatory mechanisms supporting this. Secondly, we synthesize emerging evidences showing how microbial strategies and soil management promote legume nodulation and BNF. Finally, we propose studying legume nodulation and BNF in a plant-soil-microbe system under low-P conditions. Conclusions Such a system perspective of plant, soil, and microbial strategies will provide valuable insights into mechanisms underlying nodulation under nutrient-limited soil conditions and how to explore belowground interactions for sustainable development in terrestrial ecosystems.