2026年8月17日，中国科学院南京土壤研究所陈志长等合作在《遗传学报》发表了一项研究，他们揭示了GmNIGT2a/2b介导的转录级联可缓冲高氮引发的大豆根瘤衰老。。

研究人员鉴定了一对高N响应因子GmNIGT2a/2b（硝酸盐诱导的garp型转录抑制因子）。高氮条件下GmNIGT2a/2b被GmNLP4a/b （n -like protein）激活。GmNIGT2a/2b双突变体的结节表现出固氮酶活性的加剧降低和衰老的加速，以应对高氮。RNA-seq和ap -seq分析显示，GmNIGT2a/2b负调控一系列核心n诱导基因，包括NAC、WRKY和bZIP转录因子以及海藻糖代谢基因。GmNIGT2b结合SNAP3和NAC039的启动子并抑制其表达，从而延缓结节衰老。他们的研究结果表明，GmNIGT2a/2b介导的转录调控可防止高氮下结节过度衰老，突出了结节中环境适应转录重编程的复杂性。

据了解，土壤无机氮(N)有效性是共生固氮效率的关键决定因素，因此豆科植物对N波动的适当有效响应至关重要。

附：英文原文

Title: GmNIGT2a/2b-mediated transcriptional cascade buffers high-nitrogen-triggered nodule senescence in soybean

Author: anonymous

Issue&Volume: 2026/08/17

Abstract: Soil inorganic nitrogen (N) availability is a critical determinant of symbiotic nitrogen fixation efficiency, making it essential for legumes to respond appropriately and effectively to N fluctuations. Here, we identify a pair of high N response factors GmNIGT2a/2b (NITRATE-INDUCIBLE GARP-TYPE TRANSCRIPTIONAL REPRESSOR). GmNIGT2a/2b are activated by GmNLP4a/b (NIN-like proteins) under high N. The nodules of gmnigt2a/2b double mutants exhibit exacerbated reduction in nitrogenase activity and accelerated senescence in response to high N. Integration of RNA-seq and DAP-seq analyses reveals that GmNIGT2a/2b negatively regulate a suite of core N-induced genes, including NAC, WRKY, and bZIP transcription factors as well as trehalose metabolism genes. GmNIGT2b binds to the promoters of SNAP3 and NAC039 and represses their expression, thereby delaying nodule senescence. Our results suggest that GmNIGT2a/2b-mediated transcriptional regulation prevents excessive nodule senescence in response to high N, highlighting the complexity of transcriptional reprogramming for environmental adaptation in nodules.

DOI: 10.1016/j.jgg.2026.08.006

Source:https://www.sciencedirect.com/science/article/abs/pii/S1673852726002717