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 510642, PR China.
College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, PR China.
J Hazard Mater. 2024 Dec 5;480:136074. doi: 10.1016/j.jhazmat.2024.136074. Epub 2024 Oct 6.
Aluminum (Al) toxicity is a significant limiting factor for crop production in acid soils. The functions and regulatory mechanisms of transcription factor STOP1 (Sensitive to Proton Rhizotoxicity 1) family genes in Al-tolerance have been widely studied in many plant species, except for soybean. Here, expression of GmSTOP1-3 was significantly enhanced by Al stress in soybean roots. Overexpression of GmSTOP1-3 resulted in enhanced root elongation and decreased Al content, which was accompanied by increased antioxidant capacity under Al treatment. Furthermore, RNA-seq identified 498 downstream genes of GmSTOP1-3, including genes involved in flavonoid biosynthesis. Among them, the expression of chalcone synthase (GmCHS) and isoflavone synthase (GmIFS) were highly enhanced by GmSTOP1-3 overexpression. Further quantitative flavonoid metabolome analysis showed that overexpression of GmSTOP1-3 significantly increased the content of naringenin chalcone, naringenin, and genistein in soybean roots under Al treatment, which positively correlated with the expression level of the genes relative to flavonoid biosynthesis. Notably, genistein had a significant positive correlation with the expression levels of GmIFS. Combination of Dual Luciferase Complementation (LUC) and Electrophoretic Mobility Shift Assays (EMSA) revealed that GmSTOP1-3 directly bound to the promoters of GmCHS/GmIFS and activated both genes' transcription. Taken together, these results suggest that GmSTOP1-3 enhances soybean Al tolerance partially through regulating the flavonoid synthesis.
铝（Al）毒性是酸性土壤中作物生产的一个重要限制因素。除了大豆之外，在许多植物物种中，转录因子 STOP1（对质子根毒性敏感 1）家族基因在耐铝性中的功能和调控机制已经得到了广泛的研究。在这里，Al 胁迫显著增强了大豆根系中 GmSTOP1-3 的表达。GmSTOP1-3 的过表达导致根伸长增强，Al 含量降低，同时在 Al 处理下抗氧化能力增强。此外，RNA-seq 鉴定了 GmSTOP1-3 的 498 个下游基因，包括参与类黄酮生物合成的基因。其中，查尔酮合酶（GmCHS）和异黄酮合酶（GmIFS）的表达在 GmSTOP1-3 的过表达下被高度增强。进一步的黄酮类代谢组定量分析表明，GmSTOP1-3 的过表达显著增加了 Al 处理下大豆根系中柚皮素查尔酮、柚皮素和染料木黄酮的含量，这与相对于类黄酮生物合成的基因表达水平呈正相关。值得注意的是，染料木黄酮与 GmIFS 的表达水平呈显著正相关。双荧光素酶互补（LUC）和电泳迁移率变动分析（EMSA）的组合表明，GmSTOP1-3 直接结合到 GmCHS/GmIFS 的启动子上，并激活这两个基因的转录。综上所述，这些结果表明，GmSTOP1-3 通过调节类黄酮的合成部分增强了大豆的耐铝性。
