Abstract
Abiotic stress exerts significant impact on plant’s growth, development, and productivity. Productivity of crop plants under salt stress is lagging behind because of our limited knowledge about physiological, biochemical, epigenetic, and molecular mechanisms of salt tolerance in plants. This study aimed to investigate physio-biochemical, molecular indices and defense responses of selected wheat cultivars to identify the most contrasting salt-responsive genotypes and the mechanisms associated with their differential responses. Physio-biochemical traits specifically membrane stability index, antioxidant potential, osmoprotectants and chlorophyll contents, measured at vegetative stage, were used for multivariate analysis to identify the most contrasting genotypes. Genetic and epigenetic analyses indicated the possible mechanisms associated with differential response of the wheat genotypes under salt stress. Better antioxidant potential, membrane stability, increased accumulation of osmolytes/phytophenolics, and higher K+/Na+ ratio under 200 mM NaCl stress identified Kharchia-65 to be the most salt-tolerant cultivar. By contrast, increased MDA level, reduced soluble sugar, proline, total chlorophyll, total phenolics contents, and lower antioxidant potential in HD-2329 marked it to be sensitive to the stress. Genetic and bioinformatics analyses of HKT1;4 of contrasting genotypes (Kharchia-65 and HD-2329) revealed deletions, transitions, and transversions resulting into altered structure, loss of conserved motifs (Ser-Gly-Gly-Gly and Gly-Arg) and function in salt-sensitive (HD-2329) genotype. Expression analysis of HKTs rationalized the observed responses. Epigenetic variations in cytosine methylation explained tissue- and genotype-specific differential expression of HKT2;1 and HKT2;3.
Highlights
Wheat is one of the most important cereal crops having global production of >700 million tones, and provides 20% of the daily protein requirements, and calories for 4.5 billion people globally (Arzani and Ashraf, 2017)
Morphological, biochemical, and physiological responses of the wheat genotypes showed that stress treatment with 200 mM NaCl for 14 days was most appropriate for studies on stress responses of wheat genotypes associated with physio-biochemical traits and defense pathways (Figure 1 and Supplementary Table S1)
Comparative analyses of the salt-modulated various changes occurring in the wheat genotypes and assessment of their ability to acclimatization under the stress was carried out by imposing the stress with 200 mM NaCl for 14 days only
Summary
Wheat is one of the most important cereal crops having global production of >700 million tones, and provides 20% of the daily protein requirements, and calories for 4.5 billion people globally (Arzani and Ashraf, 2017). Limited success in growing wheat on salt-affected soils has been achieved because only a few salt-tolerant bread wheat genotypes have been identified (Sairam et al, 2002). Responses of Wheat under Salt Stress few bread wheat genotypes showing tolerance to salinity and sodicity stresses. Salt stress reduce the expected yield of crops and affects metabolic processes in plants through impairment of water potential of cells, ion toxicity, membrane integrity and function, and uptake of essential mineral nutrients (Arzani and Ashraf, 2016). An enhanced knowledge of about biochemical, physiological, genetic and epigenetic aspects of salt tolerance will be helpful in cloning of the genes involved in salt tolerance, development of transgenics and better breeding programs, and in screening germplasm toward breeding for saline conditions (Sairam et al, 2002)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
