Cloning and spatiotemporal expression analysis of NtAMT1.1 in Nicotiana tabacum

Abstract Ammonium transporters (AMTs) play important roles in tobacco growth, development, and nitrogen utilization. To investigate the expression patterns and potential roles of AMTs in tobacco, the NtAMT1.1 gene was cloned from the cultivated tobacco variety K326, and bioinformatics, subcellular localization, and expression pattern analyses were conducted. The CDS of NtAMT1.1 is 1473 bp, encoding 490 amino acids. The tertiary structure of the NtAMT1.1 protein is mainly composed of α-helices and random coils. The evolutionary analysis revealed that NtAMT1.1 belongs to subgroup I and is most closely related to NbAMT1.1 in N . benthamiana . The subcellular localization analysis indicated that NtAMT1.1 is localized in the endoplasmic reticulum, and the tissue expression pattern analysis showed that NtAMT1.1 is highly expressed in senescent or mature leaves, and veins of the leaves, and the lowest expression is in flowers. The expression of NtAMT1.1 in leaves is also related to the nitrogen concentration and growth stage, with the highest expression observed in low-nitrogen leaves at the budding stage. Additionally, the expression of NtAMT1.1 is induced by various phytohormones and exhibited different expression patterns. Furthermore, transient overexpression of NtAMT1.1 in N. benthamiana leaves significantly increased the expression of nitrogen assimilation related genes. Overall, this study broadens our understanding of the nutritional physiology of ammonium nitrogen in tobacco and provides preliminary evidence for subsequent research on the mechanisms of ammonium transport genes in tobacco.