Genome-wide identification of high-affinity nitrate transporter 2 (NRT2) gene family in alfalfa (Medicago sativa)

Abstract The high-affinity nitrate transporter 2 (NRT2) proteins plays an important role in nitrate uptake and transport in plants. In this study, the NRT2s gene family was systematically analyzed in alfalfa. We showed that a total of three NRT2 members were identified from the genome database, according to their chromosomal location, they were named MsNRT2.1-2.3. The phylogenetic tree revealed that NRT2 proteins were categorized into two main subgroups, which was further confirmed by their gene structure and conserved motifs. Three MsNRT2 genes distributed on 2 chromosomes. Furthermore, we studied the expression pattern of MsNRT2 gene in six tissues based on RNA-sequencing data from the Short Read Archive (SRA) database of NCBI, and the results showed that MsNRT2 gene was widely expressed in six tissues. After treatment with drought, salt, abscisic acid (ABA) and salicylic acid (SA), We used quantitative RT-PCR to analyze the expression levels of MsNRT2 genes and the results showed that most of the MsNRT2 genes responded to these stresses. However, the individual genes play a major role under the different treatment conditions. In summary, MsNRT2 plays an irreplaceable role in the growth, development and stress response of alfalfa, and this study provides valuable information and theoretical basis for future research on MsNRT2 function.