Table 1.
Status of selenium fortification in food crops (vegetables) across the globe.
| Sr. No. | Species | Study objectives/plant species | Findings | Conclusive remarks | References |
|---|---|---|---|---|---|
| 1 | Wheat (Triticum aestivum L.), corn (Zea mays L.), rice (Oryza sativa L.), broccoli (Brassica oleracea var. italica), garlic (Allium sativum L.), onion (Allium cepa L.), leek (Allium ampeloprasum var. porrum), Indian mustard (Brassica juncea), and hyperaccumulators (e.g., Astragalus bisulcatus) | To review strategies for selenium (Se) biofortification in staple crops and Se-accumulating plants to address global Se malnutrition. | Agronomic biofortification: Foliar Se application increased Se concentrations in wheat (42-67 µg kg-1) and corn (19-36 µg kg-1); rice Se content varied widely (5–1370 ng g-1) depending on soil type. Genetic biofortification: Overexpression of genes (APS, SMT, CgS) enhanced Se accumulation and tolerance in crops (e.g., Indian mustard, tomato). Soil dynamics: Se bioavailability is higher in selenate-treated aerobic soils than selenite-treated anaerobic soils; water management (e.g., drainage) optimizes grain Se retention. Health/economic impact: Biofortified crops reduce Se deficiency-related diseases (e.g., Keshan disease) and healthcare costs, improving productivity. |
Se biofortification (via agronomic practices, genetic engineering, and soil management) is critical for combating global Se malnutrition, especially in rice-dependent regions. Future priorities: Enhance Se bioavailability, optimize genetic traits for Se accumulation in edible parts, and address challenges (e.g., consumer acceptance, heavy metal co-uptake). Multidisciplinary collaboration and policy frameworks are essential for scaling biofortification and ensuring long-term food/nutrient security |
Ranawake et al., 2025 |
| 2 | Maize (Zea mays L.), millet (Pennisetum glaucum), sorghum (Sorghum bicolor L.), and cassava (Manihot esculenta) | To assess the impact of Se-deficiency on human health in Sub-Saharan Africa. Evaluate biofortification strategies (especially agronomic biofortification) to improve selenium intake through local crops. Understand soil-plant-human transfer pathways of selenium in the region. |
Selenium deficiency is widespread across Sub-Saharan Africa, contributing to increased vulnerability to diseases, including viral infections and immune dysfunction. The selenium content in crops is highly variable due to soil type, climate, and agricultural practices. Biofortification (adding selenium to fertilizers) has shown promising results in increasing crop selenium content, particularly in Ethiopia and Malawi; Agronomic biofortification is more immediately effective compared to genetic methods or food fortification. |
Selenium deficiency is a public health challenge in Sub-Saharan Africa, deeply linked to soil quality and crop composition; Targeted interventions, especially agronomic biofortification, offer a cost-effective and scalable solution; Policymaking should prioritize integrated strategies involving agriculture, health, and nutrition to address selenium malnutrition. |
Botha et al., 2024 |
| 3 | Teff (Eragrostis tef), wheat (Triticum aestivum L.), and maize (Zea mays L.) | To estimate the health burden of selenium deficiency in Ethiopia. To assess the cost-effectiveness of agronomic biofortification (applying selenium fertilizers) in staple crops. |
Selenium deficiency contributes significantly to disease burden, particularly by weakening immune function and increasing susceptibility to infections. Agronomic biofortification could significantly reduce disability-adjusted life years (DALYs) at a relatively low cost. Regions with very low soil selenium are most at risk and benefit the most from intervention. |
Agronomic biofortification is a cost-effective intervention for improving selenium status in Ethiopia. Targeting high-risk areas and scaling up fertilization practices could yield meaningful public health improvements. Integrating this strategy into broader agricultural and nutrition programs is highly recommended. |
Abdu et al., 2023 |
| 4 | Focus is on plants role in Se management | Review selenium dynamics in agroecosystems: uptake, transport, toxicity, and sustainable management. Evaluate phytotechnologies as eco-friendly strategies to manage Se levels. |
Traditional Se remediation methods are expensive and environmentally harmful, making phytotechnologies a more sustainable alternative. There is a need for interdisciplinary collaboration to better understand Se dynamics in agricultural systems. |
A sustainable balance is needed between correcting Se deficiency and avoiding toxicity. Phytotechnologies offer viable solutions, but require more interdisciplinary research and field optimization. The review highlights the potential for eco-friendly, cost-effective strategies to manage Se in agricultural systems and improve public health. |
Somagattu et al., 2024 |
| 5 | Rice (Oryza sativa L.) | To assess Se-biofortification strategies focusing on market surveys, field sampling, and controlled experiments. | Global rice Se concentrations were 0.079 mg kg-1. 70% of East Asian paddy soils have insufficient Se bioavailability to meet global rice Se standards. Soil iron oxide content influence rice Se enrichment. Activating native soil Se (vs. exogenous addition) and water management are effective biofortification strategies. |
Prioritize activating native soil Se and optimizing water management rice Se-enrichment Address low Se bioavailability in soils and leverage farmland-to-table insights to combat Se hidden hunger. Emphasize region-specific strategies and future research on bioavailability optimization and agronomic practices. |
Ma et al., 2024 |
| 6 | Winter wheat Triticum aestivum L. | To enhance selenium (Se) content in winter wheat grains through genetic biofortification to address human Se deficiency, focusing on breeding and genetic engineering approaches. | Genetic biofortification is more sustainable than agronomic methods. Wild wheat relatives (e.g., T. dicoccoides) exhibit higher Se accumulation potential. QTLs for Se content mapped on chromosomes 3D, 5B, and others; chromosome 3D shows significant effects on Se uptake via root traits. Transgenic approaches (e.g., introducing SMT gene) increase Se accumulation but face regulatory/ethical challenges. |
Genetic biofortification offers a promising long-term solution to improve Se content in wheat. Further research is needed to validate QTLs, explore wild relatives, and address safety concerns in transgenic strategies. Combining genetic breeding with microbial-mediated biofortification may optimize outcomes. | Sunic and Spanic, 2024 |
| 7 | Various crop plants (e.g., cereals, vegetables) | To investigate optimal conditions for agronomic biofortification of iodine and selenium in crop plants to address human deficiencies. | Agronomic biofortification effectively increases iodine/selenium in crops. Optimal application methods (e.g., foliar/soil) and doses are critical for success. Awareness among producers/consumers is essential for implementation. Limited data exist on bioavailability and long-term efficacy of biofortified foods. |
Agronomic biofortification shows promise to combat iodine/selenium deficiencies, but standardized protocols and human bioavailability studies are needed. Public education and collaboration between stakeholders are key for scalability. | Oztekin and Buyuktuncer, 2024 |
| 8 | Cereals (e.g., maize (Zea mays L.), wheat (Triticum aestivum L.), rice (Oryza sativa L.) Legumes (e.g., lentil (Lens culinaris), soybeans (Glycine max L.) Vegetables (e.g., lettuce (Lactuca sativa), tomato (Solanum lycopersicum) Forages (e.g., alfalfa (Medicago sativa), ryegrass (Lolium perenne) Medicinal plants (e.g., Atractylodes macrocephala) |
To evaluate key factors influencing selenium (Se) biofortification via fertilization and optimize Se application strategies to enhance Se content in crops while minimizing yield reduction. Focused on cereals, legumes, vegetables, forages, and medicinal plants. | Plant type and Se fertilization rate are primary factors affecting Se content and yield. Se content increases with fertilization up to thresholds (164 g ha-1 for cereals, 103 g ha-1 for forages). High Se doses reduce yields, particularly in cereals. Foliar application is more effective than soil application; selenate and selenite show similar efficacy. Initial soil Se content, organic carbon, pH, and climate (temperature, precipitation) also influence outcomes. |
Balanced Se fertilization strategies (80–100 g ha-1) are critical for biofortification without yield loss. Long-term ecological monitoring and bioavailability studies are needed. Plant type-specific approaches and consideration of soil/climate factors can optimize Se biofortification. | Huang et al., 2024 |
| 9 | Major food crops (e.g., cereals, legumes, vegetables). | To evaluate the role of nanoparticles (NPs) in enhancing biofortification of food crops (e.g., cereals, legumes) to address malnutrition, focusing on NP-based strategies for increasing micronutrients (Zn, Cu, Fe, Se) in crops while minimizing environmental and health risks. | Nanotechnology is an environmentally friendly technique for enhancing nutritional value in crops. Nutrient-based nanoparticles (NPs) can increase essential micronutrients in food crops. NPs of zinc, copper, iron, and selenium are effective in boosting human immune systems against viral infections and health threats. Traditional methods like chemical fertilizers have drawbacks, including environmental degradation and reduced food quality. Nanoparticles offer a sustainable alternative to traditional fertilizers, improving both crop yield and nutritional quality. |
Nanotechnology offers sustainable biofortification solutions to combat malnutrition by improving crop nutrient content and safety. Integrating genetic/agronomic approaches with NP-based strategies can optimize crop yield, quality, and human health outcomes. Further research and adoption are needed to scale these methods globally. | Zahid et al., 2025 |
| 10 | Rice (Oryza sativa L.), with regional cultivars like Longgeng, Jingliangyou 534, Zhongzheyou 1, and Yixiangyou 2115. | To evaluate selenium (Se) distribution in Chinese rice paddy soils, analyze cultivation practices affecting Se biofortification in rice, and propose strategies to enhance Se content in rice grains. | China’s rice-growing areas show varying degrees of selenium deficiency. Selenium fertilizer application increases Se in rice grains and improves yield and quality. Nitrogen fertilizer enhances selenium content, while phosphorus and potassium fertilizers have less impact. Water management practices, especially alternate wetting and drying (AWD) irrigation, significantly affect selenium bioavailability. Different rice varieties vary in selenium content due to genetic differences. |
Region-specific water/fertilizer management and varietal selection can enhance rice Se content. Prioritize breeding Se-enriched, high-yielding rice varieties and long-term monitoring of environmental impacts. Integrating agronomic practices and genetic improvements is critical for sustainable Se biofortification in China | Li et al., 2024 |
| 11 | Wheat (Triticum aestivum L.), rice (Oryza sativa L.), soybean (Glycine max), tomato (Solanum lycopersicum), lettuce (Lactuca sativa), and garlic (Allium sativum) etc. | To evaluate the role of selenium (Se) biofortification via effective microorganisms (EM) in enhancing crop tolerance to abiotic stresses (drought, salinity, heavy metals) and improving nutritional quality. Focused on leveraging microbial interactions to increase Se accumulation in crops like wheat, rice, and vegetables. | Selenium is essential for human health, acting as an antioxidant and supporting immune function. Selenium biofortification can enhance crop nutritional quality and help address micronutrient deficiencies. Effective microorganisms (EM) can promote selenium uptake in plants and improve stress tolerance. The application of selenium through foliar sprays, soil fertilizers, and nanoparticles shows promise for increasing crop yields and quality. Excessive selenium can lead to toxicity in plants and humans, highlighting the need for careful management. |
Selenium biofortification via EM offers a sustainable strategy to address micronutrient deficiencies and abiotic stress in crops. Integrating microbial inoculants (e.g., selenobacteria) with optimized Se application (foliar/nano-forms) enhances crop resilience and nutritional value. Future research should focus on microbial mechanisms, environmental impact assessment, and regulatory frameworks to balance benefits and risks. This approach aligns with global goals for food security and sustainable agriculture | Yadav, 2024 |
| 12 | Maize (Zea mays L.), wheat (Triticum aestivum L.), soybean (Glycine max), sunflower (Helianthus annuus L.), and forage grasses | To assess the selenium (Se) status in soils, crops, livestock, and humans across Southern Africa and evaluate biofortification strategies to address deficiencies. Focused on staple crops (maize, wheat) and forages as primary dietary sources of Se for both livestock and humans. | Selenium levels in Southern African soils are generally low, leading to selenium-deficient crops, particularly maize, which is a staple food. Selenium deficiency is widespread in human and animal populations, contributing to health issues such as impaired immune function and increased susceptibility to diseases. Biofortification of crops through selenium fertilization can significantly improve selenium content in grains and pasture. Selenium supplementation in animal feed enhances selenium levels in animal products, benefiting both animal health and human nutrition. |
Southern Africa faces critical Se deficiencies in soils, crops, and populations, necessitating urgent intervention. Biofortification of staple crops (e.g., maize) via Se fertilizers or transgenic breeding is a viable solution. Integration of microbial-mediated strategies and policy support (e.g., Finland’s model) could improve Se status sustainably. Further research is needed to optimize biofortification methods, monitor long-term impacts, and address socioeconomic barriers to implementation. | Chilala et al., 2024 |
| 13 | Common bean (Phaseolus vulgaris L.) | To evaluate the effects of Se-enriched urea and ammonium sulfate on agronomic, physiological, and nutritional traits | Se-enriched fertilizers enhanced seed yield by improving key physiological processes | Se-enriched urea was found to be more effective in increasing Se concentrations in common bean seeds, likely due to increased Se availability in the soil near the urea granule. | Namorato et al., 2025 |
| 14 | Barley (Hordeum vulgare L.) | To enhance selenium (Se) content through exogenous application for addressing Se deficiency in Tibetan Plateau diets. | Exogenous Se fertilizers improved barley Se fraction which was mostly accumulated in the aleurone layer outside the inner endosperm. Pearling processing led to significant losses of Se and other micronutrients, with the removal of pearling fractions P6 resulting in a 24.10% loss of Se. | Se biofortification combined with optimized processing (e.g., reduced pearling, thermal treatments) effectively maintains Se levels in highland barley within recommended ranges, offering a sustainable strategy to combat Se deficiency in Se-deficient regions like the Tibetan Plateau. Further research on processing–nutrient interactions is needed to maximize nutritional benefits. | Li et al., 2025 |
| 15 | Cow pea (Vigna unguiculata (L.) Walp. | The study aimed to determine the genotypic variability of cowpea in response to selenium (Se) application to develop agronomic biofortification strategies. The plant species studied was cowpea. | Genotypic variation: 20 cowpea genotypes exhibited differences in yield and nitrogen efficiency. Se fertilization: Soil/foliar application of sodium selenate (0–150 g ha-1) influenced physiological traits (photosynthesis, antioxidant activity) and nutrient accumulation. Nutrient distribution: Se biofortification increased essential/beneficial elements in grains while monitoring antinutrients. Responsive genotypes showed higher Se accumulation without yield penalties. |
The results may contribute to the selection of responsive cowpea genotypes for biofortification programs and the determination of safe Se doses. This could help combat nutritional deficiencies through agronomic strategies, potentially addressing hidden hunger by enhancing the nutritional content of cowpea grains. | Lanza, 2024 |
| 16 | Allium species viz. Garlic (Allium sativum L.), onion (Allium cepa L.), leek (Allium ampeloprasum L.), chives (Allium schoenoprasum L.), and shallot (Allium cepa var. aggregatum) | To evaluate the potential of selenium (Se) biofortification in Allium crops for functional food production, focusing on genetic traits, Se chemical forms (selenate, selenite, nano-Se), application methods (soil/foliar), sulfur (S) and arbuscular mycorrhizal fungi (AMF) interactions, and hormonal regulation. Additionally, to explore the development of Se-enriched functional foods (e.g., bread with leek powder, microgreens, black garlic) and optimize cultivation strategies to enhance anti-carcinogenic properties. | The study found that Se treatment positively influenced the accumulation of secondary metabolites and plant yield in Allium species. | Allium crops exhibit high potential for Se biofortification, but responses vary due to genotype and environmental factors. Optimization strategies (e.g., biochar, Si compounds, AMF inoculation) and novel Se forms (nano/organic) are needed to enhance Se accumulation and stress resilience. These advancements could position Se-enriched Allium products as functional foods with medicinal value, addressing nutritional deficiencies and supporting sustainable agriculture. Future research should prioritize cost-effective, scalable methods and long-term safety assessments. | Golubkina et al., 2024b |
| 17 | Wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), rice (Oryza sativa L.), corn (Zea mays L.), oilseed rape (Brassica napus L.), and leafy vegetables e.g., pakchoi (Brassica rapa subsp. Chinensis), and Se hyperaccumulators like Stanleya pinnata. | To enhance selenium (Se) transfer from soil to plants via optimized agronomic strategies, focusing on improving Se bioavailability in crops (e.g., cereals, leafy greens) to address human dietary deficiencies. The review emphasizes mechanisms of Se mobilization, soil–plant interactions, and metabolic pathways in plants. | Selenium in soil exists in various chemical forms, with plants absorbing selenite and selenate. Key factors influencing Se bioavailability include redox potential, pH, organic matter, moisture, and microbial activity. Strategies to boost Se transfer involve adjusting these factors and promoting beneficial microbes. Plants can convert inorganic Se into organic forms beneficial for humans. Foliar Se application is effective but requires careful timing and concentration. | Integrated soil management (e.g., redox/pH optimization, microbial inoculation) and targeted Se application (foliar/soil) can significantly improve Se biofortification. Challenges include complex soil-plant interactions and variability in Se speciation. Future research should prioritize genotype-specific approaches, microbial consortia, and advanced technologies (e.g., nanotechnology) to maximize Se transfer and sustainability, ensuring Se-rich crops contribute to global nutritional security | Liao et al., 2024 |
| 18 | Rice (Oryza sativa L.) | To evaluate the effects of Se on rice grown in Cd-contaminated soil | The Se supplementation significantly reduced Cd accumulation in rice roots, shoots, and grain by 16.3%, 24.6%, and 37.3%, respectively. Additionally, Se influenced Cd accumulation by regulating expression of Cd transporter genes leading to phytoremediation. | Se supplementation is a promising strategy to simultaneously reduce Cd toxicity and biofortify rice with Se, particularly in lightly contaminated soils. Future research should optimize Se application methods, explore long-term environmental impacts, and investigate genotype-specific responses to maximize efficacy and sustainability. | Huang et al., 2024 |