Liu Guoxuan, Chen Qianqian, Li Dongqian, Mai Huafu, Zhou Yuming, Lin Maoxin, Feng Xiaonan, Lin Xiaoying, Lu Xing, Chen Kang, Tian Jiang, Liang Cuiyue
Root Biology Center, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, P. R. China.
Plant Cell Environ. 2025 Mar;48(3):1812-1828. doi: 10.1111/pce.15254. Epub 2024 Nov 4.
Mineral nutrient deficiencies and metal ion toxicities coexist on acid soils. Phosphorus (P) deficiency in plants is generally accompanied with significant levels of leaf manganese (Mn) accumulation. However, the molecular regulatory mechanisms underpinning remain unclear. The present study found that P-deficient soybean plants accumulated more Mn compared to P-sufficient ones on acid soils in both field and greenhouse experiments. Meanwhile, both P deficiency and Mn toxicity enhanced the expression of GmSTOP1-3. Over-expressing GmSTOP1-3 enhanced Mn accumulation in transgenic soybean hairy roots, but RNA-interference did not show obvious differences. Moreover, transgenic soybeans with GmSTOP1-3-overexpression showed enhanced root citrate exudation and augmented Mn accumulation. RNA-sequence identified four downstream genes of GmSTOP1-3, including multidrug and toxic compound extrusion (GmMATE2/13) and metal transporter genes (GmZIP6/GmIREG3), which encode plasma membrane proteins. GmSTOP1-3 activated the transcription of these four genes by directly binding to their promoter regions. In addition, both GmZIP6 and GmIREG3 functioned in Mn uptake as manifested by the higher Mn concentration and decreased growth of soybean hairy roots with their overexpression. Taken together, it is suggested that upregulation of GmSTOP1-3 by low P stress on acid soils activates transcripts of GmMATE2/13 and GmZIP6/GmIREG3, which consequently result in enhanced Mn accumulation in soybean.
在酸性土壤中，矿质养分缺乏和金属离子毒性并存。植物中的磷（P）缺乏通常伴随着叶片锰（Mn）的大量积累。然而，其潜在的分子调控机制仍不清楚。本研究发现，在田间和温室试验中，与磷充足的大豆植株相比，酸性土壤上缺磷的大豆植株积累了更多的锰。同时，缺磷和锰毒性均增强了GmSTOP1-3的表达。过表达GmSTOP1-3增强了转基因大豆毛状根中的锰积累，但RNA干扰未显示出明显差异。此外，过表达GmSTOP1-3的转基因大豆表现出根系柠檬酸分泌增加和锰积累增加。RNA测序鉴定出GmSTOP1-3的四个下游基因，包括多药和有毒化合物外排基因（GmMATE2/13）和金属转运蛋白基因（GmZIP6/GmIREG3），它们编码质膜蛋白。GmSTOP1-3通过直接结合其启动子区域激活这四个基因的转录。此外，GmZIP6和GmIREG3均在锰吸收中起作用，过表达它们会导致大豆毛状根中锰浓度升高和生长受抑制。综上所述，酸性土壤上低磷胁迫上调GmSTOP1-3激活了GmMATE2/13和GmZIP6/GmIREG3的转录，从而导致大豆中锰积累增加。
