摘要Compound leaf development requires the coordi-nation of genetic factors,hormones,and other signals.In this study,we explored the functions of Class Ⅱ KNOTTED-like homeobox(KNOXII)genes in the model leguminous plant Medicago truncatula.Phenotypic and genetic analyses sug-gest that MtKNOX4,5 are able to repress leaflet formation,while MtKNOX3,9,10 are not involved in this developmental process.Further inves-tigations have shown that MtKNOX4 represses the CK signal transduction,which is downstream of MtKNOXI-mediated CK biosynthesis.Additionally,two boundary genes,FUSED COMPOUND LEAF1(orthologue of Arabidopsis Class M KNOX)and NO APICAL MERISTEM(orthologue of Arabidopsis CUP-SHAPED COTYLEDON),are necessary for MtKNOX4-mediated compound leaf formation.These findings suggest,that among the members of MtKNOXII,MtKNOX4 plays a crucial role in in-tegrating the CK pathway and boundary regulators,providing new insights into the roles of MtKNOXII in regulating the elaboration of compound leaves in M.truncatula.