Comparative physiological and transcriptomic analyses of wheat (Triticum aestivum L.) seedlings under salt stress reveal salt tolerance mechanisms

Abstract

Wheat is an important food crop, and salt stress severely affects its growth and development. However, the salt tolerance mechanisms in wheat remain poorly understood. In this study, the salt‑tolerant variety Cangmai6002 and the salt‑sensitive variety Jimai22 were used as experimental materials. We investigated the physiological and molecular mechanisms underlying the differential responses of the two genotypes to salt stress using high‑throughput RNA sequencing. The results showed that, under salt stress, Cangmai6002 maintained a higher germination rate, greater growth vigor, and higher antioxidant enzyme activities than Jimai22. In addition, Cangmai6002 exhibited lower Na⁺ influx and higher K⁺ influx compared with Jimai22 as salt concentration increased. RNA‑seq identified 9815 and 9595 differentially expressed genes (DEGs) in Cangmai6002 and Jimai22, respectively, when compared with their corresponding control groups. These DEGs were enriched in pathways including the MAPK signaling pathway – plant, glycolysis/gluconeogenesis, plant–pathogen interaction, and plant hormone signal transduction. Notably, we observed genotype‑specific expression changes in genes involved in reactive oxygen species scavenging (POD, SOD, CAT) and ion transport (HKT, KAT, ATPase), which were consistent with the physiological differences between the two varieties. These transcriptome data serve as a preliminary resource to decipher the molecular basis of salt adaptation in wheat, and offer potential candidate genes for salt-tolerance molecular breeding.