The semi-determinate stem growth habit in leguminous crops,similar to the green revolution semi-dwarf trait in cereals,is a key plant architecture trait that affects several other traits determining grain yield.In soybean semi-determinacy is modulated by a post-domestication gain-of-function mutation in the gene,Dt2,which encodes an MADS-box transcription factor.However,its role in systemic modification of stem growth and other traits is unknown.In this study,we show that Dt2 functions not only as a direct repressor of Dt1,which prevents terminal flowering,but also as a direct activator of putative floral integrator/identity genes including GmSOC1,GmAP1,and GmFUL,which likely promote flowering.We also demonstrate that Dt2 functions as a direct repressor of the putative drought-responsive transcription factor gene GmDREB1D,and as a direct activator of GmSPCH and GmGRP7,which are potentially associated with asymmetric division of young epidermal cells and stomatal opening,respectively,and may affect the plant’s water-use efficiency (WUE).Intriguingly,Dt2 was found to be a direct activator or repressor of the precursors of eight microRNAs targeting genes potentially associated with meristem maintenance,flowering time,stomatal density,WUE,and/or stress responses.This study thus reveals the molecular basis of pleiotropy associated with plant productivity,adaptability,and environmental resilience.