Genetic associations unravel genomic regions/candidate genes of salt stress memory via enhancing antioxidant defense system in wheat.

The concept of stress memory where plants "remember" previous exposure to stress and react more robustly upon subsequent exposures has gained traction in recent years. Therefore, this study successfully identifies key genetic loci and alleles that enhance stress memory in wheat, specifically focusing on germination parameters and antioxidant activities using a genome-wide association study (GWAS) under salt stress. Our study revealed that salt-stressed wheat genotypes showed highly significant increases in all germination traits and antioxidants compared to non-stressed wheat plants. For salt-stressed wheat genotypes, SOD showed highly significant positive correlations with DW, APX, and GR (r = 0.99***, 0.99***, 0.70***), respectively. These strong correlations suggest that SOD, along with APX and GR, plays a critical role in maintaining growth and enhancing antioxidant defense mechanisms in wheat under salinity stress conditions. Inside the linkage disequilibrium, 81 significant SNP markers were detected to be associated with our trait of interest. Furthermore, the study's exploration of several potential candidate genes involved in the "stress memory" effect provides a novel perspective on the adaptive responses of wheat to salinity stress. For instance, the gene TraesCS2B02G194200 is annotated as glycosyltransferase activity. Interestingly, glycosyltransferases play a critical role in mediating salt stress tolerance in cereal crops by modulating key metabolic pathways and enhancing the stability of cellular components. The presence of the G allele in this SNP was associated with higher antioxidant content in wheat genotypes compared to those carrying the A allele, indicating that selecting wheat genotypes with the G allele could enhance antioxidant defense, potentially leading to improved tolerance to salt stress. Identifying genes associated with this effect sheds light on the molecular mechanisms that enable plants to retain and pass on adaptive responses across generations and opens new avenues for targeted breeding and genetic engineering. These genes could serve as valuable targets for developing wheat varieties with enhanced salinity tolerance, providing a means to harness and enhance natural adaptive processes through crop improvement strategies.