NHX-Type Na/H Antiporter Gene Expression Under Different Salt Levels and Allelic Diversity of in Wild and Cultivated Barleys.

Salinity tolerance is a multifaceted trait attributed to various mechanisms. Wild barley is highly specialized to grow under severe environmental conditions of Tibet and is well-known for its diverse germplasm with high tolerance to abiotic stresses. The present study focused on determining the profile of the expression of isoforms of the gene in 36 wild and two cultivated barley under salt stress. Our findings revealed that in leaves and roots, expression of and in XZ16 and CM72 was upregulated at all times as compared with sensitive ones. The and isoforms were also induced by salt stress, although not to the same extent as and Gene expression analysis revealed that and are the candidate genes that could have the function of regulators of ions by sequestration of Na in the vacuole. and showed a wide range of sequence variations in an amplicon, identified single-nucleotide polymorphisms (SNPs). Evaluation of the sequencing data of 38 barley genotypes, including Tibetan wild and cultivated varieties, showed polymorphisms, including SNPs, and small insertion and deletion (INDEL) sites in the targeted genes and . Comprehensive analysis of the results revealed that Tibetan wild barley has distinctive alleles of and which confer tolerance to salinity. Furthermore, less sodium accumulation was observed in the root of XZ16 than the other genotypes as visualized by CoroNa-Green, a sodium-specific fluorophore. XZ16 is the tolerant genotype, showing least reduction of root and leaf dry weight under moderate (150 mM) and severe (300 mM) NaCl stress. Evaluation of genetic variation and identification of salt tolerance mechanism in wild barley could be promoting approaches to unravel the novel alleles involved in salinity tolerance.