Biotechnological Approaches for Generating Zinc-Enriched Crops to Combat Malnutrition

An Ex-Ante Analysis of the Impact of Biofortified Zinc Rice on Dietary Zinc Inadequacy: Evidence from Bangladesh, Indonesia, and the Philippines

BACKGROUND

South, East and Southeast Asia are among regions of the world with the highest estimated prevalence of inadequate zinc intake. Because populations in those regions eat rice as their main staple, zinc biofortification of rice has the potential to improve zinc intake especially among the most vulnerable OBJECTIVE: We modeled the impact of consumption of zinc-biofortified rice on zinc intake and inadequacy among women of childbearing age and young children nationally in Indonesia, and the Philippines, and at a sub-national level in Bangladesh METHODS: We conducted an ex-ante analysis by applying increments of zinc content in rice, from a baseline level of 16 parts per million (ppm) to 100 ppm, and based on rice consumption data to substitute levels of conventional rice with zinc-biofortified rice varying between 10% and 70% RESULTS: Among all datasets evaluated from these three countries, the prevalence of dietary zinc inadequacy at baseline was 94 to 99% among women of childbearing age, 77 to 100% among children 4-5 years old and 27 to 78% among children 1-3 years old. At the current breeding target of 28 ppm, zinc-biofortified rice has the potential to decrease zinc inadequacy by up to 50 percent among women and children in rural Bangladesh and among children in the Philippines where consumption of rice is higher compared to Indonesia CONCLUSIONS: Our analysis shows that increasing zinc content in rice up to 45 ppm reduces the burden of zinc inadequacy substantially, after which we encourage programs to increase coverage to reach the highest number of beneficiaries.

Combined effect of endophytic Bacillus mycoides and rock phosphate on the amelioration of heavy metal stress in wheat plants

BACKGROUND

Zinc (Zn) and nickel (Ni) are nutrients that are crucial for plant growth; however, when they are present at higher concentrations, they can cause toxicity in plants. The present study aimed to isolate plant growth promoting endophytic bacteria from Viburnum grandiflorum and assess its plant and defense promoting potential alone and in combination with RP in zinc (Zn) and nickel (Ni) toxic soil. The isolated endophytic bacteria were identified using 16s rRNA gene sequencing. For the experiment, twelve different treatments were applied using Zn, Ni, isolated endophytic Bacillus mycoides (Accession # MW979613), and rock phosphate (RP). The Ni, Zn and RP were used at the rate of (100 mg/kg) and (0.2 g/kg) respectively. A pot experiment with three replicates of each treatment was conducted using a complete randomized design (CRD).

RESULTS

The results indicated that Ni (T5 = seed + 100 mg/kg Ni and T9 = seed + 100 mg/kg Zn) and Zn concentrations inhibited plant growth, but the intensity of growth inhibition was higher in Ni-contaminated soil. Bacillus mycoides and RP at 100 mg/Kg Zn (T12 = inoculated seed + 100 mg/kg Zn + RP0.2 g/kg.) increased the shoot length, leaf width, protein and sugar content by 57%, 13%, 20% and 34%, respectively, compared to the control. The antioxidant enzymes superoxide dismutases (SOD), peroxidase (POD) were decreased in contaminated soil. Furthermore, Ni and Zn accumulation was inhibited in T11 (seed + 100 mg/kg Zn + RP0.2 g/Kg) and T12 (inoculated seed + 100 mg/kg Zn + RP0.2 g/Kg) by 62 and 63% respectively. The Cu, Ca, and K, contents increased by 128, 219 and 85, Mn, Na, and K by 326, 449, and 84% in (T3 = inoculated seed) and (T4 = inoculated seed + RP 0.2 g/Kg) respectively.

CONCLUSIONS

Ni was more toxic to plants than Zn, but endophytic bacteria isolated from Viburnum grandiflorum, helped wheat (Triticum aestivum) plants and reduced the toxic effects of Ni and Zn. The effect of Bacillus mycoides was more prominent in combination with RP which promoted and suppressed heavy-metal toxicity. The reported combination of Bacillus mycoides and RP may be useful for improving plant growth and overcoming metal stress.

Genetic biofortification: advancing crop nutrition to tackle hidden hunger

Malnutrition, often termed "hidden hunger," represents a pervasive global issue carrying significant implications for health, development, and socioeconomic conditions. Addressing the challenge of inadequate essential nutrients, despite sufficient caloric intake, is crucial. Biofortification emerges as a promising solution by enhance the presence of vital nutrients like iron, zinc, iodine, and vitamin A in edible parts of different crop plants. Crop biofortification can be attained through either agronomic methods or genetic breeding techniques. Agronomic strategies for biofortification encompass the application of mineral fertilizers through foliar or soil methods, as well as leveraging microbe-mediated mechanisms to enhance nutrient uptake. On the other hand, genetic biofortification involves the strategic crossing of plants to achieve a desired combination of genes, promoting balanced nutrient uptake and bioavailability. Additionally, genetic biofortification encompasses innovative methods such as speed breeding, transgenic approaches, genome editing techniques, and integrated omics approaches. These diverse strategies collectively contribute to enhancing the nutritional profile of crops. This review highlights the above-said genetic biofortification strategies and it also covers the aspect of reduction in antinutritional components in food through genetic biofortification.

Zn application through seed priming improves productivity and grain nutritional quality of silage corn

The micronutrient application in agriculture takes place through soil application, foliar spraying or added as seed treatments. The latter method, the nutri-priming, is an appealing option due to the easiness in handling it, environment-friendly, cost effectiveness and efficient against multiple environmental stressors. To assess the feasibility of Zn-priming technique on seeds germination, two experiments were conducted and assessed the efficiency on the growth rate, yield and biofortification on the forage maize (Zea mays L.). The first laboratory experiment assessed the effect of Zn-priming for three-time exposures (i.e., 8, 16 and 24 h) on germination parameters. The second experiment was done in a greenhouse, by using the 10 seeds obtained from 24 h priming. Five seed pretreatments were studied (0, 0.1, 0.5, 1 and 11 2 % of zinc sulfate heptahydrate (ZnSO₄·7H₂O)) compared to the recommended dose (5 ppm of Zn at 5–9 leaf stage) provided by soil application. The obtained results revealed that all seed priming, including hydro-priming, improve seed germination performance. Zn-priming increased the grain yield and helped to enrich the seeds in this element, especially seedlings treated with 0.5 % Zn sulphate for 24 h leading to an increase in yield by 47 % and in Zn content by 15 %. The comparison of the results from both techniques showed that Zn-priming could be was very effective than the traditional direct application in soil.

Prolific contribution of Pseudomonas protegens in Zn biofortification of wheat by modulating multifaceted physiological response under saline and non-saline conditions

The current study aimed to characterize the contribution of bacterium CP17 in zinc (Zn) biofortification in wheat under saline and non-saline conditions. This bacterial strain effectively solubilized Zn and tolerated up to 20% NaCl concentration. The Zn-solubilization potential was also quantified using AAS in a liquid broth supplemented with zinc oxide and zinc carbonate at various NaCl concentrations. Lowering the pH of liquid broth and analyzing a wide range of organic acids (thioacetic acid, glutamic acid, carboxylic acid, propionic acid, and so on) using UPLC-MS provided mechanistic insight for zinc solubilization. This strain was also shown to possess plant probiotic characteristics like phosphate solubilization, production of siderophore, indole acetic acid (IAA), exopolysaccharide (EPS), ACC deaminase, and ammonia. CP17 was identified as a Pseudomonas protegens based on the 16S rRNA gene analysis. In addition, the amplified product of the ACC deaminase producing gene (acdS) provided a molecular indication of the strain's endurance towards stress. The towel paper assay confirmed that the inoculation of Pseudomonas protegens CP17 significantly increased wheat seedlings' germination, growth, and biomass under different NaCl concentrations (0 mM, 100 mM, and 150 mM). Afterward, In situ pot experiment study was designed with the inoculation of Pseudomonas protegens in wheat under saline and non-saline conditions. The harvested wheat plants showed an elevated pattern of zinc content in the grain (i.e. 24.33 and 29.33mg/kg), straw (i.e. 45.73 and 50.23mg/kg) and soil (i.e. 0.978 and 1.32mg/kg) under saline and non-saline conditions, respectively and shown significant improvement over control. The results of the pot study revealed the amelioration in plant health, yield and uptake of available zinc from rhizospheric soil to straw and grain, along with enhanced dehydrogenase and phosphatase activities of rhizospheric soil under saline and non-saline conditions. This study supports the integrative role of Pseudomonas protegens CP17 as a bioinoculant for the efficacious strategy of zinc biofortification and growth promotion in wheat and ensures sustainable nutrient quality production under salinity stress.

Integrated mRNA and microRNA expression analysis of root response to phosphate deficiency in Medicago sativa

The deficiency of available phosphate significantly limits plant growth and development. This study sought to investigate how alfalfa (Medicago sativa), a high-yielding and high-quality forage widely cultivated worldwide, responds to phosphate deficiency stress by integrating transcriptional and post-transcriptional data. In this study, 6,041 differentially expressed genes (DEGs) were identified in alfalfa roots under phosphate deficiency conditions. Furthermore, psRNATarget, RNAhybrid, and TargetFinder were used to predict the target genes of 137 differentially expressed miRNAs (DEMs) in the root. In total, 3,912 DEGs were predicted as target genes. Pearson correlation analysis revealed 423 pairs of miRNA-mRNA regulatory relationships. MiRNA negatively regulates mRNA involved in regulatory pathways of phosphate deficiency responses in alfalfa. miR156e targeted squamosa promoter-binding-like protein 13A (SPL13), miR160c targeted auxin response factor 18 (ARF18), and miR2587a controlled glycolysis and citrate cycle via Phosphoenolpyruvate carboxykinase (ATP) (PCKA). Novel-miR27 regulated SPX domain-containing protein that controls phosphate transport in alfalfa root, novel-miR3-targeted sulfoquinovosyl transferase SQD2 controlled sulfolipid synthesis and glutathione S-transferase (GST; mediated by miR169j/k and novel-miR159) regulated glutathione metabolism. miR399l regulated auxin-responsive protein SAUR72 involved in IAA signal transduction, while abscisic acid receptor PYL4 (regulated by novel-miR205 and novel-miR83) participated in ABA signal transduction. Combined miRNA-mRNA enrichment analysis showed that most miRNAs regulate the phosphate starvation response of alfalfa by modulating target genes involved in carbohydrate metabolism, sulfolipid metabolism, glutathione metabolism, and hormone signal transduction. Therefore, this study provides new insights into the post-transcriptional regulation mechanism of phosphate deficiency responses and new perspectives on phosphate assimilation pathways in alfalfa and other legumes.

Pleiotropic effect analysis and marker development for grain zinc and iron concentrations in spring wheat

Wheat (Triticum aestivum L.) is one of the main food crops in the world and a primary source of zinc (Zn) and iron (Fe) in the human body. The genetic mechanisms underlying related traits have been clarified, thereby providing a molecular theoretical foundation for the development of germplasm resources. In this study, a total of 23,536 high-quality DArT markers was used to map quantitative trait loci (QTL) of grain Zn (GZn) and grain Fe (GFe) concentrations in recombinant inbred lines crossed by Avocet/Chilero. A total of 17 QTLs was located on chromosomes 1BL, 2BL, 3BL, 4AL, 4BS, 5AL, 5DL, 6AS, 6BS, 6DS, and 7AS accounting for 0.38-16.62% of the phenotypic variance. QGZn.haust-4AL, QGZn.haust-7AS.1, and QGFe.haust-6BS were detected on chromosomes 4AL, 6BS, and 7AS, accounting for 10.63-16.62% of the phenotypic variance. Four stable QTLs, QGZn.haust-4AL, QGFe.haust-1BL, QGFe.haust-4AL, and QGFe.haust-5DL, were located on chromosomes 1BL, 4AL, and 5DL. Three pleiotropic effects loci for GZn and GFe concentrations were located on chromosomes 1BL, 4AL, and 5DL. Two high-throughput Kompetitive Allele Specific PCR markers were developed by closely linking single-nucleotide polymorphisms on chromosomes 4AL and 5DL, which were validated by a germplasm panel. Therefore, it is the most important that quantitative trait loci and KASP marker for grain zinc and iron concentrations were developed for utilizing in marker-assisted breeding and biofortification of wheat grain in breeding programs.

Genotypic variations for tuber nutrient content, dry matter and agronomic traits in tetraploid potato germplasm

Nutrient deficiencies lead to various health issues and are common worldwide. Potato germplasm is a rich source of natural variations and genetic variability present in it can be exploited for developing nutrient-rich high-yielding potato varieties. In this study, variations in the yield, dry matter (DM) and mineral nutrients concentrations were evaluated in both peeled and unpeeled tubers of 243 highly diverse tetraploid potato accessions. These were raised under field conditions for two consecutive years. The germplasm studied has a wider range of variations in peeled tubers DM (13.71-27.80%), Fe (17.08-71.03 mg/kg), Zn (9.55-34.78 mg/kg), Cu (2.13-13.25 mg/kg), Mn (7.04-25.15), Ca (117.4-922.5 mg/kg), Mg (656.6-1510.6 mg/kg), S (1121.3-3765.8 mg/kg), K (1.20-3.09%), P (0.21-0.50%) and Mo (53.6-1164.0 ppb) concentrations compared to popular Indian potato varieties. Higher nutrient concentrations in whole tubers compared to tuber flesh suggest that these are present in high concentration in the tuber peripheral layers and peeling off the tubers results in the loss of nutrients. Highest loss due to peeling off the tubers was observed in Fe (35.63%) followed by Cu (22.80%), Mn (21.69%), Ca (21.27%), Mg (12.89%), K (12.75%), Zn (10.13%), and Mo (9.87%). The GCV and PCV for all the traits in peeled tubers ranged from 9.67 to 29.91%, and 13.84 to 43.32%, respectively. Several significant positive correlations were observed among the parameters and the first two principal components accounted for 39.37% of total variations. The results of this study will pave a way for the development of nutrient-rich high-yielding potato varieties.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-022-01197-1.

Potato biofortification: an effective way to fight global hidden hunger

Hidden hunger is leading to extensive health problems in the developing world. Several strategies could be used to reduce the micronutrient deficiencies by increasing the dietary uptake of essential micronutrients. These include diet diversification, pharmaceutical supplementation, food fortification and crop biofortification. Among all, crop biofortification is the most sustainable and acceptable strategy to overcome the global issue of hidden hunger. Since most of the people suffering from micronutrient deficiencies, have monetary issues and are dependent on staple crops to fulfil their recommended daily requirements of various essential micronutrients. Therefore, increasing the micronutrient concentrations in cost effective staple crops seems to be an effective solution. Potato being the world's most consumed non-grain staple crop with enormous industrial demand appears to be an ideal candidate for biofortification. It can be grown in different climatic conditions, provide high yield, nutrition and dry matter in lesser time. In addition, huge potato germplasm have natural variations related to micronutrient concentrations, which can be utilized for its biofortification. This review discuss the current scenario of micronutrient malnutrition and various strategies that could be used to overcome it. The review also shed a light on the genetic variations present in potato germplasm and suggest effective ways to incorporate them into modern high yielding potato varieties.

Enhancing health benefits of milled rice: current status and future perspectives

Milled rice is an essential part of the regular diet for approximately half of the world's population. Its remarkable commercial value and consumer acceptance are mostly due to its promising cooking qualities, appealing sensory properties, and longer shelf life. However, the significant loss of the nutrient-rich bran layer during milling makes it less nutritious than the whole grain. Thus, enhancing the nutritive value of milled rice is vital in improving the health and wellbeing of rice consumers, particularly for those residing in the low-economic zones where rice is the primary source of calories and nutrition. This article provides a critical review on multiple frontiers of recent interventions, such as (1) infusing the genetic diversity to enrich amylose and resistant starch to reduce glycaemic index, (2) enhancing the minerals and vitamins through complementary fortification and biofortification as short and long-term interventions, and (3) developing transgenic solutions to improve the nutrient levels of milled rice. Additionally, the review highlights the benefits of functional ingredients of milled rice to human health and the potential of enhancing them in rice to address the triple burden of malnutrition. The potential merit of milled rice concerning food safety is also reviewed in this article.

Tracking of Zinc Ferrite Nanoparticle Effects on Pea (Pisum sativum L.) Plant Growth, Pigments, Mineral Content and Arbuscular Mycorrhizal Colonization

Important gaps in knowledge remain regarding the potential of nanoparticles (NPs) for plants, particularly the existence of helpful microorganisms, for instance, arbuscular mycorrhizal (AM) fungi present in the soil. Hence, more profound studies are required to distinguish the impact of NPs on plant growth inoculated with AM fungi and their role in NP uptake to develop smart nanotechnology implementations in crop improvement. Zinc ferrite (ZnFe₂O₄) NPs are prepared via the citrate technique and defined by X-ray diffraction (XRD) as well as transmission electron microscopy for several physical properties. The analysis of the XRD pattern confirmed the creation of a nanocrystalline structure with a crystallite size equal to 25.4 nm. The effects of ZnFe₂O₄ NP on AM fungi, growth and pigment content as well as nutrient uptake of pea (Pisum sativum) plants were assessed. ZnFe₂O₄ NP application caused a slight decrease in root colonization. However, its application showed an augmentation of 74.36% and 91.89% in AM pea plant shoots and roots’ fresh weights, respectively, compared to the control. Moreover, the synthesized ZnFe₂O₄ NP uptake by plant roots and their contents were enhanced by AM fungi. These findings suggest the safe use of ZnFe₂O₄ NPs in nano-agricultural applications for plant development with AM fungi.

Dissection of Molecular Processes and Genetic Architecture Underlying Iron and Zinc Homeostasis for Biofortification: From Model Plants to Common Wheat

The micronutrients iron (Fe) and zinc (Zn) are not only essential for plant survival and proliferation but are crucial for human health. Increasing Fe and Zn levels in edible parts of plants, known as biofortification, is seen a sustainable approach to alleviate micronutrient deficiency in humans. Wheat, as one of the leading staple foods worldwide, is recognized as a prioritized choice for Fe and Zn biofortification. However, to date, limited molecular and physiological mechanisms have been elucidated for Fe and Zn homeostasis in wheat. The expanding molecular understanding of Fe and Zn homeostasis in model plants is providing invaluable resources to biofortify wheat. Recent advancements in NGS (next generation sequencing) technologies coupled with improved wheat genome assembly and high-throughput genotyping platforms have initiated a revolution in resources and approaches for wheat genetic investigations and breeding. Here, we summarize molecular processes and genes involved in Fe and Zn homeostasis in the model plants Arabidopsis and rice, identify their orthologs in the wheat genome, and relate them to known wheat Fe/Zn QTL (quantitative trait locus/loci) based on physical positions. The current study provides the first inventory of the genes regulating grain Fe and Zn homeostasis in wheat, which will benefit gene discovery and breeding, and thereby accelerate the release of Fe- and Zn-enriched wheats.

Neglected and Underutilized Crop Species: The Key to Improving Dietary Diversity and Fighting Hunger and Malnutrition in Asia and the Pacific

Asia continues to suffer from a high prevalence of malnutrition. Persistent malnutrition can be attributed to low dietary diversity, together with low production diversity. Dietary diversity represents a more healthy, balanced, and diverse diet, which ensures nutrient adequacy. The principle of dietary diversity is affirmed in all national food-based dietary guidelines. Food-based approaches that address malnutrition, especially micronutrient deficiencies, are embedded in evidence-based healthy diet patterns; however, they are disconnected from the current agricultural production system. Promising neglected and underutilized species (NUS) that are nutrient-dense, climate-resilient, profitable, and locally available/adaptable are fundamental to improving dietary and production diversity. The Future Smart Food Initiative, led by FAO's Regional Initiative on Zero Hunger, aims to harness the enormous benefits of NUS in the fight against hunger and malnutrition. Recognizing that NUS covers crops, livestock, fisheries and aquaculture, and forests, the FAO has set crops as an entry point for NUS to address hunger and malnutrition.

Rice Biofortification With Zinc and Selenium: A Transcriptomic Approach to Understand Mineral Accumulation in Flag Leaves

Human malnutrition due to micronutrient deficiencies, particularly with regards to Zinc (Zn) and Selenium (Se), affects millions of people around the world, and the enrichment of staple foods through biofortification has been successfully used to fight hidden hunger. Rice (Oryza sativa L.) is one of the staple foods most consumed in countries with high levels of malnutrition. However, it is poor in micronutrients, which are often removed during grain processing. In this study, we have analyzed the transcriptome of rice flag leaves biofortified with Zn (900 g ha-1), Se (500 g ha-1), and Zn-Se. Flag leaves play an important role in plant photosynthesis and provide sources of metal remobilization for developing grains. A total of 3170 differentially expressed genes (DEGs) were identified. The expression patterns and gene ontology of DEGs varied among the three sets of biofortified plants and were limited to specific metabolic pathways related to micronutrient mobilization and to the specific functions of Zn (i.e., its enzymatic co-factor/coenzyme function in the biosynthesis of nitrogenous compounds, carboxylic acids, organic acids, and amino acids) and Se (vitamin biosynthesis and ion homeostasis). The success of this approach should be followed in future studies to understand how landraces and other cultivars respond to biofortification.

Genetic Analysis of Agronomic Traits and Grain Iron and Zinc Concentrations in a Doubled Haploid Population of Rice (Oryza sativa L.)

The development of micronutrient dense rice varieties with good agronomic traits is one of the sustainable and cost-effective approaches for reducing malnutrition. Identification of QTLs for high grain Fe and Zn, yield and yield components helps in precise and faster development of high Fe and Zn rice. We carried out a three-season evaluation using IR05F102 x IR69428 derived doubled-haploid population at IRRI. Inclusive composite interval mapping was carried out using SNP markers and Best Linear Unbiased Estimates of the phenotypic traits. A total of 23 QTLs were identified for eight agronomic traits and grain Fe and Zn concentration that explained 7.2 to 22.0% PV. A QTL by environment interaction analysis confirmed the stability of nine QTLs, including two QTLs for Zn on chromosomes 5 and 12. One epistatic interaction for plant height was significant with 28.4% PVE. Moreover, five QTLs were identified for Fe and Zn that harbor several candidate genes, e.g. OsZIP6 on QTL qZn_5.1. A number of QTLs were associated with a combination of greater yield and increased grain Zn levels. These results are useful for development of new rice varieties with good agronomic traits and high grain Zn using MAS, and identification of genetic resources with the novel QTLs for grain Zn.

Production and Implication of Bio-Activated Organic Fertilizer Enriched with Zinc-Solubilizing Bacteria to Boost up Maize (Zea mays L.) Production and Biofortification under Two Cropping Seasons

Bio-activated organic fertilizers (BOZ) were produced by enriching the zinc oxide (ZnO)-orange peel waste composite with Zn solubilizing bacteria (ZSB: Bacillus sp. AZ6) in various formulations (BOZ1 (9:1), BOZ2 (8:2), BOZ3 (7:3) and BOZ4 (6:4)). The produced BOZs, along with ZnO, ZnSO4, ZSB were applied to maize crop (Zea mays L.) under field conditions in two different cropping season and the growth, yield, physiology, plant Zn contents and quality of maize were investigated. Results revealed significant variation in the aforementioned parameters with the applied amendments. The BOZ4 performed outclass by exhibiting the highest plant growth, yield, physiology, Zn contents, and quality. On average, an increase of 53%, 49%, 19%, 22%, 10%, 4%, and 30% in plant height was noticed with BOZ4 application over control, ZnO, ZnSO4, BOZ1, BOZ2, BOZ3, and ZSB, respectively. BOZ4 enhanced the dry shoot-biomass 46% than control. Likewise, the photosynthetic rate, transpiration rate, stomatal conductance, chlorophyll contents, carotenoids, and carbonic anhydrase activity were increased by 47%, 42%, 45%, 57%, 17%, and 44%, respectively, under BOZ4 over control in both cropping seasons. However, BOZ4 reduced the electrolyte leakage by 38% as compared to control in both cropping seasons. BOZ4 increased the Zn contents of grain and shoot by 46% and 52%, respectively, while reduced the phytate contents by 73% as compared to control. Application of BOZ4 revealed highest average fat (4.79%), crude protein (12.86%), dry matter (92.03%), fiber (2.87%), gluten (11.925%) and mineral (1.53%) contents, as compared to control. In general, the impact of cropping seasons on maize growth, yield, physiology, Zn contents, and quality were non-significant (with few exceptions). Thus, bio-activation of ZnO with ZSB could serve as an efficient and economical strategy for boosting up the growth, yield, physiological, and quality parameters of maize under field conditions.

Rice Biofortification: High Iron, Zinc, and Vitamin-A to Fight against “Hidden Hunger”

One out of three humans suffer from micronutrient deficiencies called “hidden hunger”. Underprivileged people, including preschool children and women, suffer most from deficiency diseases and other health-related issues. Rice (Oryza sativa), a staple food, is their source of nutrients, contributing up to 70% of daily calories for more than half of the world’s population. Solving “hidden hunger” through rice biofortification would be a sustainable approach for those people who mainly consume rice and have limited access to diversified food. White milled rice grains lose essential nutrients through polishing. Therefore, seed-specific higher accumulation of essential nutrients is a necessity. Through the method of biofortification (via genetic engineering/molecular breeding), significant increases in iron and zinc with other essential minerals and provitamin-A (β-carotene) was achieved in rice grain. Many indica and japonica rice cultivars have been biofortified worldwide, being popularly known as ‘high iron rice’, ‘low phytate rice’, ‘high zinc rice’, and ‘high carotenoid rice’ (golden rice) varieties. Market availability of such varieties could reduce “hidden hunger”, and a large population of the world could be cured from iron deficiency anemia (IDA), zinc deficiency, and vitamin-A deficiency (VAD). In this review, different approaches of rice biofortification with their outcomes have been elaborated and discussed. Future strategies of nutrition improvement using genome editing (CRISPR/Cas9) and the need of policy support have been highlighted.