Unraveling salinity stress responses in ancestral and neglected wheat species at early growth stage: A baseline for utilization in future wheat improvement programs

Abstract

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

Effects of salinity stress on seedling biomass, physiochemical properties, and grain yield in different breeding wheat genotypes

“…Hence, the K + /Na + ratio is considered one of the main physiological strategies adopted by plants to resist salt stress (Singh et al 2019). Our results suggest that ion concentrations and high K + /Na + ratios may be useful selection indices for salt tolerance, consistent with the ndings of Genc et al (2010), Xu et al (2012), Masoudi et al (2015), and Ahmadi et al (2020). We observed that genotypes G5 and G20 showed the lowest SN and highest RK, SK, RKN, and SKN.…”

“…Several studies revealed that fresh and dry weights of both roots and shoots of wheat seedlings were negatively affected by different levels of salinity (Athar et al 2007; Afzal et al 2008;Ghiyasi et al 2008;Akbarimoghaddam et al 2011). Reduction of photosynthetic processes and its related parameters under salinity conditions were also reported by Guo et al (2015), Zou et al (2016), and Ahmadi et al (2020).…”

MGIDI and WAASB indices: The useful approaches for selection of salt-tolerant barley genotype at the early growth and maturity stages

“…However, some genotypes with the minimum reduction in growth and physiological features showed a relative ability to cope with salinity effects (Tables 2-4). Several studies reported similar results in barley and other crops (Tavakkoli et al 2010;Ahmadi et al 2018;Rajeswari et al 2019;Ahmadi et al 2020). The root system is the first plant organ that encounter directly in contact with the saline solutions in the soil and gets damage (Alam et al 2015;Rasel et al 2020).…”

Evaluating and Screening of Agro-Physiological Indices for Salinity Stress Tolerance in Wheat at the Seedling Stage

“…It has been argued that AKT1 overexpression improves osmotic and stress tolerance by increasing tissue levels of K + ( Ahmad et al, 2016 ). With advances in molecular biology and biotechnology tools, the roles of TaHKT1;5 and TaSOS1 in Na + exclusion and its mechanisms have been exhaustively characterized in previous research ( Zhu et al, 2016a ; Wu et al, 2018 ; Ahmadi et al, 2020 ). However, there are few studies on TaAKT1 , and its mechanism in maintaining K + homeostasis under salt stress needs further research.…”