Symbiotic nitrogen fixation is an energy-expensive process, and the light available to plants has been proposed to be a primary influencer. We demonstrate that the light-induced soybean TGACG-motif binding factor 3/4 (GmSTF3/4) and FLOWERING LOCUS T (GmFTs), which move from shoots to roots, interdependently induce nodule organogenesis. Rhizobium-activated calcium- and calmodulin-dependent protein kinase (CCaMK) phosphorylates GmSTF3, triggering GmSTF3–GmFT2a complex formation, which directly activates expression of nodule inception (NIN) and nuclear factor Y (NF-YA1 and NF-YB1). Accordingly, the CCaMK–STF–FT module integrates aboveground light signals with underground symbiotic signaling, ensuring that the host plant informs its roots that the aboveground environment is prepared to sustainably supply the carbohydrate necessary for symbiosis. These results suggest approaches that could enhance the balance of carbon and nitrogen in the biosphere.

中文翻译：

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芽中光诱导的移动因子调节根瘤菌引发的大豆根结瘤

共生固氮是一个耗能的过程，植物可用的光被认为是主要影响因素。我们证明光诱导的大豆 TGACG 基序结合因子 3/4 (GmSTF3/4) 和 FLOWERING LOCUS T (GmFTs) 从芽转移到根，相互依赖地诱导根瘤器官发生。根瘤菌激活的钙和钙调蛋白依赖性蛋白激酶 (CCaMK) 磷酸化 GmSTF3，触发 GmSTF3-GmFT2a 复合物形成，从而直接激活结节起始 (NIN) 和核因子Y（NF - YA1和NF-YB1）的表达。因此，CCaMK-STF-FT模块将地上光信号与地下共生信号相结合，确保宿主植物告知其根，地上环境已准备好可持续地供应共生所需的碳水化合物。这些结果提出了可以增强生物圈中碳和氮平衡的方法。