Morphological and Physiological Responses of Wheat to Salt Stress: Enhancing Tolerance with Glycine Betaine and Identifying Key Genes via Comparative Transcriptome Analysis

Abstract

Abstract Salinity stress poses a critical challenge to global wheat production, especially in arid and semi-arid regions such as the Middle East, salinity poses a significant challenge to global agriculture, degrading vast areas of arable land and threatening crop productivity. Wheat, as a staple cereal crop, is particularly susceptible to its adverse effects, highlighting the urgent need for sustainable management strategies. Salinity stress adversely affects wheat at all growth stages, from germination to grain harvest, reducing vegetative growth, reproductive capacity, and ultimately grain yield. This study investigates the impact of elevated salinity (0–160 mM NaCl) on wheat germination, growth, and the molecular mechanisms of stress tolerance mechanisms. The protective role of glycine betaine (GB), a cellular osmolyte that mitigates salinity-induced stress by enhancing cellular osmolality and supporting osmotic adjustment, on plant performance and reprogramming the response transcriptome was evaluated. Besides discovering important genes and pathways involved in the salt stress tolerance of wheat (Triticum aestivum L.). Nine wheat varieties were screened for tolerance to salinity, revealing genotype-specific responses. Based on finding morphological, physiological and molecular wheat response salt-tolerant varieties were Sama, 32357, and 32271, 35326 and Alderon showed enhanced proline accumulation (>8 µmol/g) under high salinity, while others like 35540, 35276, Cochise, and Najran were most sensitive. Comparative transcriptome studies of GB treatment of salt-tolerant and salt-sensitive genotypes revealed hundreds of differentially expressed genes (DEGs) associated with oxidative stress, ion transport, and osmotic adjustment. Important functions include cell wall metabolism, fatty acid production, and cytoskeletal dynamics, all necessary for stress tolerance were found by GO (Gene ontology) enrichment studies. By raising wheat's resistance to salt, GB treatment affected stress responsive gene expression by means of improved physiological and molecular pathways for adaptation. These findings offer essential genetic insights that can support molecular breeding initiatives and agronomic practices to enhance wheat resilience and productivity in regions impacted by salinity, thereby fostering sustainable food security amidst global challenges. Themes: Glycine Betaine (GB), sustainability, Osmoprotectante & Environment, RNA sequencing, differentially expressed genes (DEGs), gene ontology (GO), salt stress & wheat.