Abstract
Nitrate transporters play important roles in nitrogen (N) uptake and utilization in plants. The function of nitrate transporter 2 (NRT2) in model plants under low-N (LN) conditions has been studied, but there are few studies on non-model plants, including Tartary buckwheat (an important medicinal and edible crop). In this study, seven NRT2 genes were identified in Tartary buckwheat genome. All the FtNRT2 proteins were localized to the cell membrane with 10-12 transmembrane domains, and have the common structural characteristics of NRT2. Expression analysis showed FtNRT2.1 was expressed in all tissues, FtNRT2.3/2.4 were specifically expressed in roots, and FtNRT2.6/2.7 were specifically expressed in seeds. Under LN, the expression of FtNRT2.1/2.4 was induced, while FtNRT2.3 was suppressed. The root-specific expressed gene FtNRT2.4 may be the key NRT2 member for regulating LN response by sequence, molecular docking, and expression analysis. Overexpression of FtNRT2.4 in tobacco improved plant growth and N uptake under 0 and 5 mM N conditions. An ancillary protein of FtNRT2.4, FtNRT3.2, was characterized by yeast two-hybrid and firefly luciferase complementation assays. In addition, 14 transcription factors (TFs) may involve in the regulation of FtNRT2.4 expression by co-expression analysis. FtNF-YB8, a TF localized in cytoplasm and nucleus, can bind to the promoter of FtNRT2.4 by yeast one-hybrid analysis. Dual-luciferase reporter analysis showed that FtNF-YB8 improved the expression of FtNRT2.4. These findings indicated the important role of FtNRT2.4 in LN response and provide new insights into the regulatory function of NRT2. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-025-01670-7.