National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Rice Biology in Henan Province, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou 450002, China.
Key Laboratory of Rice Biology in Henan Province, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou 450002, China.
Mol Plant. 2023 Mar 6;16(3):588-598. doi: 10.1016/j.molp.2023.01.009. Epub 2023 Jan 21.
Modern semi-dwarf rice varieties of the "Green Revolution" require a high supply of nitrogen (N) fertilizer to produce high yields. A better understanding of the interplay between N metabolism and plant developmental processes is required for improved N-use efficiency and agricultural sustainability. Here, we show that strigolactones (SLs) modulate root metabolic and developmental adaptations to low N availability for ensuring efficient uptake and translocation of available N. The key repressor DWARF 53 (D53) of the SL signaling pathway interacts with the transcription factor GROWTH-REGULATING FACTOR 4 (GRF4) and prevents GRF4 from binding to its target gene promoters. N limitation induces the accumulation of SLs, which in turn promotes SL-mediated degradation of D53, leading to the release of GRF4 and thus promoting the expression of genes associated with N metabolism. N limitation also induces degradation of the DELLA protein SLENDER RICE 1 (SLR1) in an D14- and D53-dependent manner, effectively releasing GRF4 from competitive inhibition caused by SLR1. Collectively, our findings reveal a previously unrecognized mechanism underlying SL and gibberellin crosstalk in response to N availability, advancing our understanding of plant growth-metabolic coordination and facilitating the design of the strategies for improving N-use efficiency in high-yield crops.
现代半矮秆水稻品种是“绿色革命”的产物，为了获得高产，需要大量施用氮肥（N）。为了提高氮素利用效率和农业可持续性，我们需要更好地理解氮代谢和植物发育过程之间的相互作用。在这里，我们表明，独脚金内酯（SLs）可以调节根系代谢和发育，以适应低氮供应，从而确保有效吸收和转运可用氮。SL 信号通路的关键抑制因子 DWARF 53（D53）与转录因子 GROWTH-REGULATING FACTOR 4（GRF4）相互作用，防止 GRF4 结合到其靶基因启动子上。氮限制诱导 SLs 的积累，而 SLs 又促进 D53 的 SL 介导的降解，从而释放 GRF4，进而促进与氮代谢相关的基因表达。氮限制还以 D14 和 D53 依赖的方式诱导 DELLA 蛋白 SLENDER RICE 1（SLR1）的降解，有效地将 GRF4 从 SLR1 引起的竞争抑制中释放出来。总之，我们的发现揭示了氮供应响应中 SL 和赤霉素交叉对话的一个以前未被认识的机制，加深了我们对植物生长代谢协调的理解，并为提高高产作物的氮素利用效率提供了策略设计的依据。
