DNA damage response (DDR) contributes to seed quality by guarding genome integrity in the delicate phases of pre- and post-germination. As a key determinant of stress tolerance and resilience, DDR has notable implications on the wider scale of the agroecosystems challenged by harsh climatic events. The present review focuses on the existing and documented links that interconnect DDR efficiency with an array of molecular hallmarks with biochemical, molecular, and physiological valence within the seed metabolic networks. The expression of genes encoding DDR sensors, transducers, mediators, and effectors is interpreted as a source of conserved hallmarks, along with markers of oxidative damage reflecting the seed’s ability to germinate. Similarly, the accumulation patterns of proteins and metabolites that contribute to DNA stability are predictive of seed quality traits. While a list of candidates is presented from multiple models and crop species, their interaction with chromatin dynamics, cell cycle progression, and hormonal regulation provides further levels of analysis to investigate the seed stress response holistically. The identification of novel hallmarks of DDR in seeds constitutes a framework to prompt validation with different experimental systems, to refine the current models of pre-germinative metabolism, and to promote targeted approaches for seed quality evaluation.
DNA damage response (DDR), a complex network of cellular pathways that cooperate to sense and repair DNA lesions, is regulated by several mechanisms, including microRNAs. As small, single-stranded RNA molecules, miRNAs post-transcriptionally regulate their target genes by mRNA cleavage or translation inhibition. Knowledge regarding miRNAs influence on DDR-associated genes is still scanty in plants. In this work, an in silico analysis was performed to identify putative miRNAs that could target DDR sensors, signal transducers and effector genes in wheat. Selected putative miRNA-gene pairs were tested in an experimental system where seeds from two wheat mutant lines were irradiated with 50 Gy and 300 Gy gamma(γ)-rays. To evaluate the effect of the treatments on wheat germination, phenotypic and molecular (DNA damage, ROS accumulation, gene/miRNA expression profile) analyses have been carried out. The results showed that in dry seeds ROS accumulated immediately after irradiation and decayed soon after while the negative impact on seedling growth was supported by enhanced accumulation of DNA damage. When a qRT-PCR analysis was performed, the selected miRNAs and DDR-related genes were differentially modulated by the γ-rays treatments in a dose-, time- and genotype-dependent manner. A significant negative correlation was observed between the expression of tae-miR5086 and the RAD50 gene, involved in double-strand break sensing and homologous recombination repair, one of the main processes that repairs DNA breaks induced by γ-rays. The results hereby reported can be relevant for wheat breeding programs and screening of the radiation response and tolerance of novel wheat varieties.