背景回顾：Legume-rhizobium symbiosis in root nodules fixes nitrogen to satisfy the plant’s nitrogen demands. The nodules’ demand for energy is thought to determine nitrogen fixation rates. 

Schematic diagram of carbon-nitrogen metabolism in legume nodules.

提出问题：How this energy state is sensed to modulate nitrogen fixation is unknown. 

主要发现：Here, we identified two soybean (Glycine max) cystathionine β-synthase domain–containing proteins, nodule AMP sensor 1 (GmNAS1) and NAS1-associated protein 1 (GmNAP1). 

结果1-NAS1+NAP1-NFYC10a：In the high–nodule energy state, GmNAS1 and GmNAP1 form homodimers that interact with the nuclear factor-Y C (NF-YC) subunit (GmNFYC10a) on mitochondria and reduce its nuclear accumulation. 

结果2-NFYC10a-磷酸烯醇式丙酮酸-氮固定：Less nuclear GmNFYC10a leads to lower expression of glycolytic genes involved in pyruvate production, which modulates phosphoenolpyruvate allocation to favor nitrogen fixation. 

结论：Insight into these pathways may help in the design of leguminous crops that have improved carbon use, nitrogen fixation, and growth.

The model of GmNAS1 and GmNAP1 regulating the response of nodule NFC to elevated NES.

根瘤中的豆科植物-根瘤菌共生系统能够固氮，从而满足植物对于氮素的需求。根瘤对于能量的需求被认为是固氮率的决定因素。但是，根瘤如何感知这种能量状态，从而调控氮固定，这一过程还不清楚。本文中，作者在大豆中鉴定到了两个含有胱硫醚β合成酶结构域的蛋白，即GmNAS1和GmNAP1。在根瘤处于高能量态时，GmNAS1和GmNAP1会在线粒体上形成同源二聚体，与NF-YC亚基GmNFYC10a上互作，减少后者在核中的积累。核内GmNFYC10a的减少会导致参与丙酮酸生产的糖酵解基因的表达下调，从而调控了磷酸烯醇式丙酮酸的分配，促进能量转向氮固定。本文所报道的研究结果将有助于未来设计出碳利用、氮固定以及生长性能改良的豆类作物。

** 王学路 **