Investigating biochemical changes and protein profile of salt-tolerant and salt-sensitive wheat cultivars in response to salinity stress

In a pot experiment, biochemical response of two wheat cultivars, KRL 1–4 and UP 2338 (Triticum aestivum L.), was assessed under varying salinity levels. Salinity was applied at three concentrations (100, 200, and 300 mM NaCl), and untreated plants served as controls. Samples were collected at 20, 30, and 40 days after sowing (DAS) to evaluate proline content, total reducing sugar content, total nitrogen content, and total protein content. SDS-PAGE was used for protein profiling. Results demonstrated that proline and reducing sugars increased with higher salinity, particularly in the tolerant KRL 1–4 cultivar. Conversely, total nitrogen and protein content decreased with rising salt concentrations, and sensitive UP 2338 cultivar exhibited more pronounced reductions. The impact of salinity on protein synthesis was investigated, revealing a new 17 kDa protein exclusively present in tolerant cultivar. Another new protein of approximately 87 kDa was observed in 100 mM NaCl-treated sample of sensitive cultivar. 23 kDa protein increased in 200 and 300 mM NaCl-treated sensitive cultivar, while it remained constant in the treated tolerant samples. Proteins within 20–30 kDa range were more abundant in tolerant cultivar, while both cultivars showed decreased levels of proteins at 68, 66, 44, and 38 kDa, with sensitive cultivar experiencing more significant reductions. These findings provide insights into biochemical responses of wheat cultivars to salinity stress and identify potential protein markers associated with salt tolerance.