Unveiling into Genetic Architecture of Transgenerational Stress Memory via Promoting Drought Tolerance in Barley

Abstract

Understanding how transgenerational stress memory in a core collection of barley accessions influences seed germination and seedling parameters under drought stress conditions is essential to enhancing its adaptability and sustainability in the face of climate change. In our study, we used the Genome-Wide Association Scan (GWAS) to investigate the genetic architecture of causative alleles controlling drought stress memory in a diverse collection of 138 barley genotypes during early developmental stages. During the seed germination test, it was observed that all genotypes exhibited a decrease in both germination percentage (G%) and germination pace (GP) when comparing seeds from Non-Stressed Plants (NP) to seeds from Stressed Plants (SP). The decrease in G% was 19% and the decrease in GP was 67%. These findings suggest that Transgenerational Stress Memory (TSM) may result in a more enduring form of stress memory. The TSM genetic linkages revealed highly significant Quantitative Trait Loci (QTNs) for all traits. A significant quantitative trait nucleotide (QTN) at position 509,466,648 base pairs, has been identified in the candidate gene HORVU.MOREX.r3.5HG0502630. This QTN is responsible for regulating the variance in shoot weight (SP FW) and dry weight (DW) and is controlled by the E3 ubiquitin-protein ligase RNF123. Interestingly, E3s participate in dehydration-responsive element-binding protein 2 A (DREB2A) that mediates stress signaling, including drought. Therefore, identifying this potential key gene that is associated with TSM, might be pivotal for effective germination and seed establishment of barley under drought conditions.