Systematic identification, evolution and expression analyses of Brachypodium distachyon NHX gene family in response to salinity

Salinity stress is a major abiotic factor affecting plant cultivation and productivity worldwide. Brachypodium distachyon emerged as a model for understanding stress adaptation mechanisms in grasses. Here, Sodium/Hydrogen antiporter gene (NHX) family in B. distachyon (BdNHX) was systemically identified, characterized and their expression pattern was assessed in response to salinity by Real Time q-PCR. Overall, 8 NHX genes were identified in the B. distachyon genome ( BdNHX1-8 ). Phylogenetic, motifs and gene structure analyses allowed the classification of BdNHX genes into 3 groups as a function of their subcellular localization: Vacuole (Vac-Class), endosomal (Endo-Class) and plasma membrane (PM-Class). Protein-protein interactions (PPIs) network determination indicated that several BdNHX proteins interacts with CIPK24, CBL4 and KEA4, implying their involvement in CBL-CIPK pathway. Expression studies using Real Time quantitative-PCR (RT q-PCR) revealed the upregulation of specific BdNHX genes under salinity in both leaves and roots, suggesting their involvement in salinity tolerance mechanisms in B. distachyon. Collectively, these results provided valuable targets of B. distachyon NHX members for genetic engineering to improve grasses resilience to salinity.