Unraveling wheat's response to salt stress during early growth stages through transcriptomic analysis and co-expression network profiling.

ABSTRACT

BACKGROUND: Soil salinization is one of the vital factors threatening the world's food security. To reveal the biological mechanism of response to salt stress in wheat, this study was conducted to resolve the transcription level difference to salt stress between CM6005 (salt-tolerant) and KN9204 (salt-sensitive) at the germination and seedling stage. RESULTS: To investigate the molecular mechanism underlying salt tolerance in wheat, we conducted comprehensive transcriptome analyses at the seedling and germination stages. Two wheat cultivars, CM6005 (salt-tolerant) and KN9204 (salt-sensitive) were subjected to salt treatment, resulting in a total of 24 transcriptomes. Through expression-network analysis, we identified 17 modules, 16 and 13 of which highly correlate with salt tolerance-related phenotypes in the germination and seedling stages, respectively. Moreover, we identified candidate Hub genes associated with specific modules and explored their regulatory relationships using co-expression data. Enrichment analysis revealed specific enrichment of gibberellin-related terms and pathways in CM6005, highlighting the potential importance of gibberellin regulation in enhancing salt tolerance. In contrast, KN9204 exhibited specific enrichment in glutathione-related terms and activities, suggesting the involvement of glutathione-mediated antioxidant mechanisms in conferring resistance to salt stress. Additionally, glucose transport was found to be a fundamental mechanism for salt tolerance during wheat seedling and germination stages, indicating its potential universality in wheat. Wheat plants improve their resilience and productivity by utilizing adaptive mechanisms like adjusting osmotic balance, bolstering antioxidant defenses, accumulating compatible solutes, altering root morphology, and regulating hormones, enabling them to better withstand extended periods of salt stress. CONCLUSION: Through utilizing transcriptome-level analysis employing WGCNA, we have revealed a potential regulatory mechanism that governs the response to salt stress and recovery in wheat cultivars. Furthermore, we have identified key candidate central genes that play a crucial role in this mechanism. These central genes are likely to be vital components within the gene expression network associated with salt tolerance. The findings of this study strongly support the molecular breeding of salt-tolerant wheat, particularly by utilizing the genetic advancements based on CM6005 and KN9204.