In this study, we analyzed the behavior of several neglected, ancestral, and domesticated wheat genotypes, including Ae. triuncialis, Ae. neglecta, Ae. caudata, Ae. umbellulata, Ae. tauschii, Ae. speltoides, T. boeoticum, T. urartu, T. durum, and T. aestivum under control and salinity stress to assess the mechanisms involved in salinity tolerance. Physiological and biochemical traits including root/shoot biomasses, root/shoot ion concentrations, activity of antioxidant enzymes APX, SOD, and GXP, and the relative expression of TaHKT1;5, TaSOS1, APX, GXP, and MnSOD genes were measured. Analysis of variance (ANOVA) revealed significant effects of the salinity treatments and genotypes for all evaluated traits. Salinity stress (350 mM NaCl) significantly decreased root/shoot biomasses, K ? concentration in root/shoot, and root/shoot K ? /Na ? ratios. In contrast, salinity stress significantly increased Na ? concentration in root and shoot, activity of antioxidant enzymes (APX, SOD, and GPX) and relative expression of salt tolerance-related genes (TaHKT1;5, TaSOS1, APX, GPX, and MnSOD). Based on heat map and principal component analysis, the relationships among physiological traits and relative expression of salt-responsive genes were investigated. Remarkably, we observed a significant association between the relative expression of TaHKT1;5 with root K ? concentration and K ? /Na ? ratio and with TaSOS1. Taken together, our study revealed that two neglected (Ae. triuncialis) and ancestral (Ae. tauschii) wheat genotypes responded better to salinity stress than other genotypes. Further molecular tasks are therefore essential to specify the pathways linked with salinity tolerance in these genotypes. Keywords Antioxidant enzymes Á Na ? transporter genes Á Salt tolerance Á Wild relatives of wheat Abbreviations SFW Shoot fresh weight RFW Root fresh weight SDW Shoot dry weight RDW Root dry weight LN Leaf Na ? concentration LK Leaf K ? concentration RN Root Na ? concentration RK Root K ? concentration LKN K ? /Na ? ratio of leaf RKN K ? /Na ? ratio of root APX activity Ascorbate peroxidase activity GPX activity Guaiacol peroxidase activity SOD activity Superoxide dismutase activity APX gene APX gene expression GPX gene GPX gene expression SOD gene MnSOD gene expression SOS1 gene TaSOS1 gene expression TaHKT1;5 gene TaHKT1;5 gene expression
