Phosphorus(P)is an essential element for plant growth and development,and is also easily fixed by soil particles due to its chemical properties.To cope with low P stress,plants have developed a wide range of adaptive strategies.In this study,we investigated the possible mechanisms and genetic strategies to improve P efficiency in leguminous crops,especially in soybean.Our results highlight the novel techniques to reconstruct 3D root architecture and in situ dynamically quantify its changes.We found that shallower root system contributes largely to enhanced soluble phosphorus(phosphate,Pi)acquisition in crops,probably due to the heterogeneous distribution of Pi along soil profile.Accompanied with changes of root morphology and architecture,increased secretion of malate and acid phosphatases(APases)in leguminous crops also facilitates mobilization of the fixed P forms in soils.Furthermore,functional analysis of SPX members led to find that the adaptive strategies in leguminous crops are well conserved and tightly mediated by the P signaling network.