Soybean (Glycine max L.) is an important agricultural crop for human food and animal feed. Soybean yield is severely constrained by abiotic stresses such as salinity and drought, which affect large proportions of arable and irrigated lands worldwide. This necessitates the development of new soybean varieties tolerant to these stress factors. Mutation breeding is an effective approach to improve the stress tolerance of plants due to increased genetic diversity. In this study, two gamma-induced salinity and drought-tolerant soybean mutants (SM1 and SM3-1) were compared with the parental line S04-05 using GO and KEGG pathway enrichment analyses. GO enrichment analyses revealed extensive differential gene expression in the mutant lines under stress conditions, with significant enrichment of pathways related to photosynthesis, hormone signaling, carbohydrate metabolism, and flavonoid and isoflavonoid biosynthesis. Genotype-specific analyses indicated that the SM3-1 mutant exhibited a dynamic regulatory response associated with maintaining the photosynthetic apparatus and chloroplast homeostasis under stress, whereas the SM1 mutant showed an adaptation strategy based on metabolite-mediated osmotic adjustment and ROS scavenging. Compared to the parental variety S04-05, the mutants showed distinct metabolic regulation in phenylpropanoid/isoflavone metabolism, with upregulation of many isoflavone biosynthesis genes under salinity, drought, and untreated conditions, indicating a key and sustained role of this pathway in stress tolerance. Most SNPs identified in the isoflavone biosynthesis pathway consist of moderate-impact and modifier variations. These findings suggest that gamma mutagenesis and subsequent selection processes allow for the development of novel genetic variants that operate through different physiological and metabolic mechanisms but exhibit similar levels of tolerance. In this respect, the study reveals that mutation breeding is a potentially sustainable and effective breeding strategy for increasing abiotic stress tolerance in soybeans.

Aging is associated with various physiological and molecular changes, including epigenetic reprogramming and metabolic remodeling. N-alpha-acetyltransferase 40 (NAA40), encoded by naa40, has emerged as a key factor connecting chromatin dynamics to cellular metabolism among epigenetic regulators. NAA40 specifically acetylates the N-termini of histones H4 and H2A, thereby influencing gene expression and maintaining the metabolic balance. In mammalian systems, the depletion of NAA40 increases intracellular acetyl-CoA levels, which impacts lipid metabolism and stress response pathways. However, the overall effects of naa40 deletion in organisms are not fully understood. In this study, we examined the functional consequences of naa40 deletion in Schizosaccharomyces pombe by analyzing changes in chronological lifespan, glucose consumption, lipid metabolism, and oxidative stress. Our findings indicate that the loss of NAA40 significantly extends the lifespan, decreases glucose utilization, alters lipid distribution, and reduces lipid peroxidation. These metabolic changes are similar to the cellular adaptations observed under calorie restriction. Our results support a model in which naa40 deletion triggers chromatin remodeling and reprograms the metabolic pathways, ultimately leading cells to a quiescent-like state characterized by increased stress resistance and extended survival. These findings underscore the importance of NAA40 as a critical link between epigenetic regulation and the mechanisms that promote metabolic longevity.