"以磷增氮"是豆科作物传统的高产栽培措施之一。磷直接参与调控根瘤固氮过程，但其内在的生理及分子调控机制尚未清楚。我们前期克隆了一个大豆根瘤特异、受低磷诱导表达的基因，GmNEF1。在大豆毛根中超量表达GmNEF1显著改善了大豆氮磷营养及结瘤状况，调控了大豆根瘤中部分磷饥饿响应基因的表达（如GmPT5等），暗示GmNEF1参与调控了根瘤对低磷胁迫的适应性。本研究拟获得超量或抑制GmNEF1表达的、稳定遗传的大豆整株转基因材料，通过RNA-seq技术，对转基因和野生型大豆根瘤基因表达谱进行比较分析；结合酵母双杂交技术，鉴定GmNEF1的互作蛋白并进行功能分析。以期明确GmNEF1调控根瘤响应低磷胁迫的分子调控网络，加强对豆科作物"以磷增氮"调控机制的理解，为进行大豆氮磷协同高效遗传改良提供理论依据和种质资源。

Phosphorus application facilitating nitrogen efficiency improvement is a technique of high-yield cultivation in legume crops. Phosphorus is directly involved in nitrogen fixation in nodules. However, physiological and molecular mechanisms underlying the process remain largely unknown. In our previous study, we have cloned a phosphate starvation induced and nodule specific gene, GmNEF1. Overexpressing GmNEF1 led to improving phosphorus and nitrogen content, as well as nodulation in soybean hairy roots. Furthermore, expression levels of some phosphate starvation responsive genes (e.g., GmPT5) were regulated by GmNEF1 in nodules, suggesting that GmNEF1 is directly involved in nodule adaptation to phosphorus deficiency. In the present study, we intend to obtain the stable genetic transgenic soybean plants with overexpressing or suppressing GmNEF1. Then, the transcriptomes of wild type and transgenic nodules will be investigated and compared via RAN-sequence; Using the yeast two-hybrid technique, the protein interacted with GmNEF1 will be identified and functionally analyzed. All the results together will demonstrate the phosphate responsive network as regulated by GmNEF1 in soybean nodules, result in further understandings of the mechanisms underlying phosphorus application facilitating nitrogen efficiency improvement, provide theoretic basis and germplasm for developing both phosphorus and nitrogen efficient soybean varieties through genetic breeding.