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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.

Hidden hunger, or micronutrient deficiency, is a worldwide problem. Several approaches are employed to alleviate its effects (e.g., promoting diet diversity, use of dietary supplements, chemical fortification of processed food), and among these, biofortification is considered as one of the most cost-effective and highly sustainable. Rice is one of the best targets for biofortification since it is a staple food for almost half of the world’s population as a high-energy source but with low nutritional value. Multiple biofortified rice lines have been produced during the past decades, while few studies also reported modifications in germination behavior (in terms of enhanced or decreased germination percentage or speed). It is important to underline that rapid, uniform germination, and seedling establishment are essential prerequisites for crop productivity. Combining the two traits, biofortified, highly-nutritious seeds with improved germination behavior can be envisaged as a highly-desired target for rice breeding. To this purpose, information gathered from transcriptomics studies can reveal useful insights to unveil the molecular players governing both traits. The present review aims to provide an overview of transcriptomics studies applied at the crossroad between biofortification and seed germination, pointing out potential candidates for trait pyramiding.

Drought poses a significant threat to global food security, particularly impacting rice cultivation during the germination stage. In this study, a soil-based system that utilizes soil moisture content was used to simulate optimal and stress conditions to assess the effect of the specific seed priming protocols on germination. Eleven rice varieties, representative of indica and japonica subspecies, grown in different ecosystems and having diverse nutrient contents, were treated with water or solutions of either poly-gamma-glutamic acid (γ-PGA) or denatured γ-PGA. Collected data regarding germinability and stress indices revealed different drought sensitivity between japonica and indica subspecies and genotype-specific responses to priming. Particularly, γ-PGA improved germination of highly susceptible indica varieties whereas water soaking was more effective for the moderately sensitive japonica varieties. Integrative analyses evidenced differences between biofortified and non-biofortified rice under γ-PGA treatment, suggesting a possible correlation between γ-PGA efficacy and Zn/Fe seed content. These findings underline that priming strategies should be tailored based on genotype and therefore this factor should be always taken under consideration for future works. The current study provides relevant information for optimizing seed priming techniques to sustain the development of drought-resilient crops as a sustainable strategy to address agricultural resilience and safeguard food security amidst environmental challenges.

More than two billion people are micronutrient deficient. Polished grains of popular rice varieties have concentration of approximately 2 μg g−1 iron (Fe) and 16 μg g−1 zinc (Zn). The HarvestPlus breeding programs for biofortified rice target 13 μg g−1 Fe and 28 μg g−1 Zn to reach approximately 30% of the estimated average requirement (EAR). Reports on engineering Fe content in rice have shown an increase up to 18 μg g−1 in glasshouse settings; in contrast, under field conditions, 4 μg g−1 was the highest reported concentration. Here, we report on selected transgenic events, field evaluated in two countries, showing 15 μg g−1 Fe and 45.7 μg g−1 Zn in polished grain. Rigorous selection was applied to 1,689 IR64 transgenic events for insert cleanliness and, trait and agronomic performances. Event NASFer-274 containing rice nicotianamine synthase (OsNAS2) and soybean ferritin (SferH-1) genes showed a single locus insertion without a yield penalty or altered grain quality. Endosperm Fe and Zn enrichment was visualized by X-ray fluorescence imaging. The Caco-2 cell assay indicated that Fe is bioavailable. No harmful heavy metals were detected in the grain. The trait remained stable in different genotype backgrounds.

Climate change poses major challenges to the agri-food sector, with drought episodes, defined as extended periods of limited water availability, representing one of the most damaging stress factors. While drought tolerance has been extensively studied during vegetative and reproductive stages, its effects on seed germination remain comparatively underexplored. This is particularly relevant for maize ( Zea mays ), a globally relevant staple crop whose productivity is highly sensitive to water deficit, making the identification of drought-tolerant varieties a high priority. Addressing this challenge requires sustainable agricultural practices. Plant-based biostimulants (PBs), derived from natural sources, are gaining attention for their ability to promote plant growth, enhance stress resilience, and reduce reliance on synthetic fertilizers, thus supporting both bioeconomy and environmental sustainability. Similarly, seed priming, a pre-sowing technique that improves germination efficiency, offers an additional strategy to strengthen crop resilience. In this study, 26 Italian maize genotypes were evaluated for their drought-tolerance potential. Biostimulants produced from plant waste by-products (red chicory and cauliflower extracts) were applied as seed priming agents and the germination performance under drought stress was monitored over a 14 days period. The germination behavior was evaluated by calculating several parameters, including germination percentage, speed, seedling growth, and stress tolerance index. In addition, reactive oxygen species (ROS) accumulation was quantified in the dry seeds of selected genotypes, alongside the expression of genes involved in ROS homeostasis and drought response. The obtained results reveal genotype-dependent responses to drought and demonstrate that priming treatments enhanced both drought tolerance and germination performance in several maize genotypes. This study emphasizes the value of genetic diversity and highlights the potential of seed priming with plant-based biostimulants as a sustainable strategy within the framework of circular bioeconomy and climate-resilient agriculture.

Water stress brought about by climate change is among the major global concerns threatening food security. Rice is an important staple food which requires high water resources. Being a semi-aquatic plant, rice is particularly susceptible to drought. The aim of this work was to develop techniques directed to promote rice resilience to water deprivation stress during germination by implementing specific seed priming treatments. Five popular Italian rice varieties were subjected to priming treatments using novel, sustainable solutions, like poly-gamma-glutamic acid (γ-PGA), denatured γ-PGA (dPGA), and iron (Fe) pulsing, alone or in combination. The effect of the developed priming methods was tested under optimal conditions as well as under water deprivation stress imposed by polyethylene glycol (PEG) treatments. The priming efficacy was phenotypically determined in terms of germination behavior by measuring a series of parameters (germinability, germination index, mean germination time, seed vigor index, root and shoot length, germination stress tolerance index). Biochemical analyses were carried out to measure the levels of iron uptake and accumulation of reactive oxygen species (ROS). Integrative data analyses revealed that the rice varieties exhibited a strong genotype- and treatment-specific germination behavior. PEG strongly inhibited germination while most of the priming treatments were able to rescue it in all varieties tested except for Unico, which can be defined as highly stress sensitive. Molecular events (DNA repair, antioxidant response, iron homeostasis) associated with the transition from seed to seedling were monitored in terms of changes in gene expression profiles in two varieties sensitive to water deprivation stress with different responses to priming. The investigated genes appeared to be differentially expressed in a genotype-, priming treatment-, stress- and stage-dependent manner. The proposed seed priming treatments can be envisioned as sustainable and versatile agricultural practices that could help in addressing the impact of climate challenges on the agri-food system.

Biofortification of rice (Oryza sativa L.) using a transgenic approach to increase the amount of iron in the grain is proposed as a low-cost, reliable, and sustainable solution to help developing countries combat anemia. In this study, we generated and evaluated a large number of rice or soybean ferritin over-accumulators in rice mega-variety IR64, including marker-free events, by introducing soybean or rice ferritin genes into the endosperm for product development. Accumulation of the protein was confirmed by ELISA, in situ immunological detection, and Western blotting. As much as a 37- and 19-fold increase in the expression of ferritin gene in single and co-transformed plants, respectively, and a 3.4-fold increase in Fe content in the grain over the IR64 wild type was achieved using this approach. Agronomic characteristics of a total of 1,860 progenies from 58 IR64 single independent transgenic events and 768 progenies from 27 marker-free transgenic events were evaluated and most trait characteristics did not show a penalty. Grain quality evaluation of high-Fe IR64 transgenic events showed quality similar to that of the wild-type IR64. To understand the effect of transgenes on iron homeostasis, transcript analysis was conducted on a subset of genes involved in iron uptake and loading. Gene expression of the exogenous ferritin gene in grain correlates with protein accumulation and iron concentration. The expression of NAS2 and NAS3 metal transporters increased during the grain milky stage.

Developing nutritious rice with a higher yield is one approach to alleviating the problem of micronutrient deficiency in developing countries, especially human malnutrition involving zinc and iron (Fe) deficiency, and achieving better adoption. The transport of micronutrients such as Fe and Zn is mainly regulated via the nicotianamine synthase ( OsNAS ) gene family, whereas yield is a complex trait that involves multiple loci. Genome editing via CRISPR (clustered regularly interspaced short palindromic repeat)-Cas9, focusing on the OsNAS2 promoter, particularly the deletion of the cis -regulatory element ARR1AT at position −933, was conducted for an enhanced accumulation of Zn in the grain and per plant. The results showed that our promoter editing increased Zn concentration per plant. Evidence also showed that an improved spikelet number per main panicle led to increased grain per plant. The traits were inherited in “transgene-free” and homozygous plant progenies. Further investigation needs to be conducted to validate trait performance under field conditions and elucidate the cause of the spikelet increase.

Rice (Oryza sativa) cultivation is highly relevant for global food security, yet germination may be conditioned by the presence of the rice hull. Using hulled or dehulled rice seeds can affect germination because the hull acts as both a physical barrier and a source of inhibitory compounds. While dehulling may speed germination by improving water and gas exchange and removing allelochemicals, it also increases vulnerability to damage and pathogens. Specific seed treatments can help mitigate these challenges. This study investigated the effects of mechanical dehulling and seed soaking with different elicitors, including hydrogen peroxide (H2O2), Hammada scoparia extracts, and ferrous sulfate, on Vialone Nano rice seed emergence and early vigor. Key findings revealed that dehulled seeds presented better emergence compared to hulled seeds, likely due to the removal of physical barriers and improved water uptake. However, hulled seeds were more responsive to the treatments, showing marked improvements in emergence speed and seedling vigor. The results demonstrate that while dehulling provides a natural advantage, seed treatments with elicitors effectively bridges the performance gap for hulled seeds. These strategies may offer sustainable approaches to improve crop establishment and overall productivity in the local rice farming systems.

Background/Objectives: The increased frequency of extreme weather events related to climate change, including the occurrence of extreme temperatures, severely affects crop yields, impairing global food security. Heat stress resulting from temperatures above 30 °C is associated with poor germination performance and stand establishment. The combination of climate-resilient crop genotypes and tailored seed priming treatments might represent a reliable strategy to overcome such drawbacks. This work explores the potential of hydropriming as a tool to mitigate the heat-stress-mediated impact on germination performance in orphan legumes. Methods: For each tested species (Lathyrus sativus L., Pisum sativum var. arvense and Trigonella foenum-graecum L.), two accessions were investigated. Germination tests were performed at 25 °C, 30 °C, 35 °C and 40 °C to assess the heat stress tolerance threshold. Hydropriming was then applied and germination tests were performed at 40 °C to test the impact of the treatment on the seeds’ ability to cope with heat stress. An alkaline comet assay and Quantitative Real Time-Polymerase Chain Reaction were performed on embryos excised from primed and control seeds. Results: Phenotyping at the germination and seedling development stage highlighted the accession-specific beneficial impact of hydropriming under heat stress conditions. In L. sativus seeds, the alkaline comet assay revealed the dynamics of heat stress-induced DNA damage accumulation, as well as the repair patterns promoted by hydropriming. The expression patterns of genes involved in DNA repair and antioxidant response were consistently responsive to the hydropriming and heat wave conditions in L. sativus accessions.