Genome-wide identification and gene expression analysis of AhNHXs in peanut

Abstract Background The Na⁺/H⁺ antiporter (NHX) family plays a crucial role in regulating intracellular Na and H homeostasis in plants. This study conducted a genome-wide analysis and expression assessment of peanut NHXs under different stress conditions. Results Fourteen AhNHXs were identified based on the Na⁺/H⁺ exchange domain, and all contained the amiloride-binding site that inhibits Na+ transport in plants. Phylogenetic analysis grouped these genes into three subfamilies. Cis-regulatory element analysis identified elements associated with hormone signaling, stress responses, and tissue-specific expression. qRT-PCR results indicated their roles in salt stress, selenium stress, and tolerance to metal ion toxicity such as cadmium, manganese, and aluminum. For instance, AhNHX4, AhNHX5, and AhNHX7 were upregulated in roots under salt, cadmium, and aluminum treatments, whereas AhNHX7 was downregulated in roots under selenium and manganese stress and in leaves under all stress conditions. Conclusions This study examined the evolutionary, structural, and functional characteristics of the AhNHX family and highlighted their roles in multiple stress responses in peanut. These findings provide insight into potential applications for improving crop tolerance to abiotic stress.