Transcriptome-level dissection provides unique insights into the salt tolerance in spelt (Triticum spelta L.)

BACKGROUND: Soil salinity severely limits wheat production. Spelt (Triticum spelta. L.) represents a valuable genetic resource for improving the salt tolerance of common wheat, but its underlying mechanisms remains poorly understood. RESULTS: Field evaluation of 22 spelt accessions identified 12 salt-tolerant genotypes. Further screening under a NaCl gradient (0-200 mM) selected three superior accessions CWI44398, CWI78968, and CWI44183. Under 150 mM NaCl, these three accessions exhibited greater shoot growth than the salt-tolerant control Jimai 22, while root development was more sensitive. Transcriptomic analysis revealed distinct expression patterns among genotypes, with common pathways including abiotic stress response and MAPK signaling, alongside genotype-specific pathways such as sulfur metabolism and fatty acid elongation. Expression patterns analysis under salt stress further confirmed the RNA-seq results, identifying four positively regulated genes. CONCLUSIONS: This study identified three salt-tolerant spelt accessions and elucidated conserved and genotype-specific molecular mechanisms, providing valuable resources for salt tolerance breeding in wheat.