Genome-Wide Identification of the AMT Gene Family and Its Expression Profiling under Ammonium Nutrition and Pathogen in Wheat

Background: Ammonium nitrogen (NH₄⁺) serves as a vital nitrogen source, playing pivotal regulatory roles in plant growth, development, and high-yield formation. Ammonium transporters (AMTs), encoded by the AMT gene family, are central to NH4+ transport. However, the functional roles of AMT genes in wheat remain poorly understood. Methods: In this study, a total of 21 TaAMT members were identified. A comprehensive genome-wide analysis was conducted, encompassing investigations into gene structure, protein motif composition, gene duplication events, collinearity relationships, and cis-acting regulatory elements. Furthermore, the expression patterns of distinct TaAMT members were examined under varying ammonium supply conditions and pathogen stress. Results: All TaAMT proteins exhibited hydrophobic characteristics and localized to the plasma membrane. Phylogenetic analysis clustered these genes into four distinct subgroups. Comparative analyses of gene structure and conserved motifs revealed conserved domain composition and motif organization within each subgroup. Interspecific synteny analysis highlighted evolutionary conservation across species. Promoter region analysis identified multiple cis-regulatory elements associated with hormone signaling, light responsiveness, and abiotic stress adaptation. Expression profiling demonstrated that TaAMT members exhibit both tissue-specific and constitutive expression patterns across developmental stages. RT-qPCR further revealed that the expression of TaAMT members responds to varying concentrations of ammonium nitrogen supply, as well as infection stresses caused by stripe rust and powdery mildew. Conclusions: Collectively, this study provides the useful molecular information into the roles of TaAMT members in nitrogen use efficiency and disease resistance, offering valuable genetic resources for wheat breeding programs aimed at enhancing agronomic traits.