Li Hong-Liang, Liu Ran-Xin, Wu Xiang, Guo Xin-Long, Li Shan-Shan, Wang Tian-Tian, Guo Yan-Yan, Wang Xiao-Fei, You Chun-Xiang
State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, National Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China.
Mol Hortic. 2025 Sep 3;5(1):57. doi: 10.1186/s43897-025-00172-0.
Nitrogen (N) is essential for the physiological metabolism, growth, and development of plants. Plants have evolved a complex regulatory network for the efficient regulation of N uptake and utilization to adapt to fluctuations in environmental N levels. However, the mechanisms underlying the regulation of N absorption and utilization in apple remain unclear. Here, we identified MdILR3 (IAA-LEUCINE RESISTANT3) as an upstream regulator of MdNRT2.4 through yeast one-hybrid (Y1H) screening. MdILR3 overexpression significantly up-regulated the expression of MdNRT2.3/2.4 and MdNIA1, resulting in an increase in nitrate content and nitrate reductase activity. Y1H and EMSA assays revealed that MdILR3 directly interacted with the promoters of MdNRT2.3/2.4 and MdNIA1. Furthermore, MdILR3 can directly bind to the promoter of MdSWEET12 and activate its expression, thereby regulating sucrose transport to provide energy for N uptake in roots. In summary, we provide physiological and molecular evidence suggesting that MdILR3 may positively regulate nitrate response by activating the expression of genes related to N uptake and sugar transport. Our findings suggest that genetic improvements in apple could enhance its ability to absorb and utilize N.
氮(N)对于植物的生理代谢、生长和发育至关重要。植物已经进化出一个复杂的调控网络,用于有效调节氮的吸收和利用,以适应环境氮水平的波动。然而,苹果中氮吸收和利用的调控机制仍不清楚。在这里,我们通过酵母单杂交(Y1H)筛选鉴定出MdILR3(异亮氨酸抗性3)作为MdNRT2.4的上游调节因子。MdILR3过表达显著上调了MdNRT2.3/2.4和MdNIA1的表达,导致硝酸盐含量和硝酸还原酶活性增加。Y1H和电泳迁移率变动分析(EMSA)实验表明,MdILR3直接与MdNRT2.3/2.4和MdNIA1的启动子相互作用。此外,MdILR3可以直接结合到MdSWEET12的启动子上并激活其表达,从而调节蔗糖转运,为根系吸收氮提供能量。总之,我们提供了生理和分子证据,表明MdILR3可能通过激活与氮吸收和糖转运相关的基因表达来正向调节硝酸盐响应。我们的研究结果表明,苹果的遗传改良可以提高其吸收和利用氮的能力。