Proteomic reprogramming underlies climate-associated variation in seed dormancy and germination of European beech

The ability of seeds to survive until dormancy recedes and the germination requirements are met is an adaptive strategy. Proteomics improves our understanding of the mechanisms that control the adaptation to environmental heterogeneity. In this study, we investigated two European beech populations from different habitats that differed in dormancy and germination traits. We found that the populations exhibited different germination strategies, which were reflected in coordinated but quantitatively different proteomic reprogramming. The Miękinia population exhibited stronger accumulation of proteins involved in nucleotide sugar biosynthesis, S-adenosylmethionine metabolism, and flavonoid biosynthesis. Enhanced nucleotide sugar biosynthesis indicates more intensive cell wall remodelling and carbohydrate metabolism, which support embryo growth and faster germination. Increased S-adenosylmethionine metabolism suggests the epigenetic and hormonal regulation of germination differences between populations. Higher flavonoid biosynthesis indicates an enhanced antioxidant capacity associated with environmental protection. In contrast, the Wisła population showed stronger accumulation of proteins involved in RNA processing, suggesting tighter post-transcriptional regulation and proteome reorganization during germination. Consistent with its deeper dormancy and later germination, the Wisła population appears to rely more on RNA-level regulation, whereas the Miękinia population prioritizes metabolic activation. These contrasting proteomic profiles likely reflect population-specific physiological strategies associated with dormancy depth and adaptation to different climatic conditions.