Liu Xiaoqian, Cai Yupeng, Yao Weiwei, Chen Li, Hou Wensheng
State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
National Center for Soybean Improvement, National Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing 210095, China.
Plant Physiol. 2024 Dec 23;197(1). doi: 10.1093/plphys/kiae478.
Soybean (Glycine max) is a globally important crop; however, its productivity is severely impacted by phosphorus (P) deficiency. Understanding the transcriptional regulation of low P (LP) response mechanisms is essential for enhancing soybean P use efficiency. In this study, we found that the Nuclear Factor-Y (NF-Y) transcription factor GmNF-YC4, in addition to its previously discovered role in regulating flowering time, possesses other functions in modulating root morphology and P uptake. Knockout of GmNF-YC4 notably boosted root proliferation and P uptake while also influencing the expression of genes related to LP stress. GmNF-YC4 acts as a specific DNA-binding transcriptional repressor, modulating the expression of the soybean α-EXPANSIN 7 (GmEXPA7) gene, which encodes a cell-wall-loosening factor, through direct binding to its promoter region. Further investigation revealed that GmEXPA7 expression is predominantly root-specific and induced by LP. Moreover, overexpression of GmEXPA7 in soybean hairy roots enhanced LP tolerance by stimulating root growth and P uptake. We further screened and obtained more potential target genes of GmNF-YC4 via DNA affinity purification sequencing, including those related to LP stress. These findings underscore the pivotal role of the GmNF-YC4-GmEXPA7 module as a key regulator in mitigating LP stress in soybeans.
大豆（Glycine max）是一种全球重要的作物；然而，其生产力受到磷（P）缺乏的严重影响。了解低磷（LP）响应机制的转录调控对于提高大豆磷利用效率至关重要。在本研究中，我们发现核因子-Y（NF-Y）转录因子GmNF-YC4，除了其先前发现的调控开花时间的作用外，在调节根形态和磷吸收方面还具有其他功能。敲除GmNF-YC4显著促进了根的增殖和磷吸收，同时也影响了与LP胁迫相关基因的表达。GmNF-YC4作为一种特异性DNA结合转录抑制因子，通过直接结合大豆α-扩张蛋白7（GmEXPA7）基因的启动子区域来调节其表达，该基因编码一种细胞壁松弛因子。进一步研究表明，GmEXPA7的表达主要在根中特异性表达，并受LP诱导。此外，在大豆毛状根中过表达GmEXPA7通过刺激根生长和磷吸收增强了对LP的耐受性。我们通过DNA亲和纯化测序进一步筛选并获得了更多GmNF-YC4的潜在靶基因，包括与LP胁迫相关的基因。这些发现强调了GmNF-YC4-GmEXPA7模块作为缓解大豆LP胁迫的关键调节因子的关键作用。
