Transcriptome profiling and field evaluation reveal salt tolerance mechanisms in a novel wheat mutant

To analyze salt-tolerant genes and related metabolic pathways in wheat and to screen for salt-tolerant germplasm resources, the common wheat variety ‘Ningchun No. 4’ and its mutant Mutant-6 were used as experimental materials. Seedlings were subjected to 250 mmol/L salt stress for 0 h, 12 h, and 24 h. Transcriptome expression changes were analyzed, and salt tolerance was evaluated through field trials conducted in saline-alkali soil. After 12 h of salt stress, 2,350 and 755 differentially expressed genes were activated in Ningchun No. 4 and the mutant, respectively. After 24 h of treatment, the numbers increased to 7,223 and 15,286 differentially expressed genes. KEGG enrichment analysis showed that Ningchun No. 4 exhibited significant enrichment in signal transduction pathways at 12 h, which shifted to basal metabolism pathways by 24 h. In contrast, the mutant showed sustained enrichment in secondary metabolism pathways throughout the treatment period. Protein interaction network analysis further identified eight core genes involved in the salt stress response. Field phenotyping in saline-alkali soil revealed that the mutant had significantly greater plant height, flag leaf length, tiller number, and grain number per spike compared to Ningchun No. 4, while no significant differences were observed in spike length, internode length below the spike, flag leaf width, spikelet number, or grains per spikelet. This study provides theoretical support for elucidating the regulatory pathways of salt tolerance in wheat and lays a foundation for establishing a field-based system for identifying salt tolerance.