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.

豆类作物中半确定的茎生长习性，类似于谷物中的“绿色革命”半矮性状，是关键的植物结构性状，会影响其他决定谷物单产的性状。在大豆中，半确定性由基因Dt2的驯化后功能获得性突变调节，该基因编码MADS-box转录因子。然而，其在茎生长和其他性状的系统修饰中的作用尚不清楚。在这项研究中，我们表明Dt2不仅充当Dt1的直接阻遏物，从而阻止末端开花，而且还充当假定的花卉整合子/同一性基因（包括GmSOC1，GmAP1和GmFUL）的直接激活剂。，这可能会促进开花。我们还证明Dt2充当假定的干旱反应转录因子基因GmDREB1D的直接阻遏物，并充当GmSPCH和GmGRP7的直接激活物，这可能分别与年轻表皮细胞的不对称分裂和气孔开放有关，并且可能影响工厂的用水效率（WUE）。有趣的是，发现Dt2是八个microRNA的前体的直接激活物或阻遏物，其靶向可能与分生组织维持，开花时间，气孔密度，WUE和/或应激反应相关的基因。因此，这项研究揭示了与植物生产力，适应性和环境适应性相关的多效性的分子基础。