Yeast twohybrid assay and bimolecular fluorescence complementation assay (BiFC) were performed to identify the interaction of these transcription factors IPN2,NSP2,CYCLOPS,and DELLA involved in regulating the expression of the symbiotic gene during nodulation in the model legume Lotus japonicus. The results showed that Lotus DELLA interacted with IPN2,NSP2,and CYCLOPS,indicating that IPN2 and DELLA may form a large protein complex to regulate the spatialtemporal expression of the nodule inception gene in legumes.