Biofortification Of Rice Research Articles

Rice Germplasm: Source of Iron and Zinc for Nutritional Security

Rice is the most important food crop, more than half (½) of the world’s population depends on it for their sustainable livelihood. Population growth is increasing day by day and it will reach more than > 9 billion by 2050, and to feed the overpopulation we need to produce nearly double amount of food grains to fulfil the demand. It was projected that Global rice yields and consumption rate will rise by 12% and 13% respectively by the year 2027 (FAO 2018). The Green Revolution has played a prime role in the 1960s -1970s to increase agricultural productivity worldwide to make many countries in food self-sufficiency leading to food secured world. The present situation is posing serious challenge for global food security in coming decades due to climate change, limited availability of arable land and water, more over other natural resources are continued to exhaustion. Rice is consumed as sole source of energy mainly in South and Southeast Asia, Africa, and Latin America which causes micronutrients deficiency leading to chronic malnutrition. Malnutrition due to inadequate intake of micronutrients mostly iron and zinc can lead to ‘Hidden Hunger’, which is responsible for many diseases. Important micronutrients Fe and Zn deficiencies in rice promoting the hidden hunger and causes anemia, stunted growth, poor cognitive development for iron deficiency and for zinc deficiency that causes reduced immunity, diarrhea, lesions on skin, mental lethargy. Approximately 2 billion people are suffering from malnutrition deficiencies for iron and zinc. Micronutrient elements Fe and Zn are available in various local rice varieties which ranged from 6.3-24.4 mg/kg Fe and 13.53- 58.4 mg/kg Zn. Biofortification of rice can assist to alleviate malnutrition associated diseases among the poor people those who are depended on rice as staple food for 40-70% daily caloric intake. Nutritional studies recommended that 24–28 mg/ kg Zn and 13 mg/ kg Fe concentration in polished grain is vital to attain the 30% of human estimated average requirement. Biofortification of cereal foods through conventional breeding can be a good opportunity to improve micronutrient deficiency in the diets. Wild rice accessions (Oryza rufipogon, O.nivara, O. latifolia and O. officinalis) may be used to improve the mineral nutrition in rice grain through breeding and conserve as important resources.

An economic analysis of biofortified rice varieties

Rice provides up to 60 per cent of the daily energy requirement. The current popular rice varieties grown in India have an incomplete amino acid profile and limited zinc. The development of high zinc rice varieties by ICAR-Indian Institute of Rice Research and high protein variety by ICAR-National Rice Research Institute is an effort to address malnutrition through biofortification in rice. This study was undertaken to assess the economic performance of zinc biofortified rice varieties and to analyse the technology efficacy of protein biofortification in rice. Information on input-output details, cost of production, yields and output prices and other variables pertaining to DRR Dhan 45 for the kharif season of 2017 were collected through a survey from 150 farmers of Telangana. The results revealed that the economic performance of the zinc biofortifed rice varieties was at par with Samba Mahsuri, a popular variety of the study area. The study also revealed that the technology efficacy of the protein biofortification of rice was in the range of 31 to 39 per cent and 62 to 74 per cent under pessimistic and optimistic scenarios, respectively. Large scale adoption of biofortified rice varieties depend on the availability of seed, certification and premium market price for the biofortified products.

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.

Genomic marker assisted identification of genetic loci and genes associated with variation of grain zinc concentration in rice

A study was conducted to examine the genetic divergence and to determine the genetic loci and genes associated with natural variation of grain zinc (Zn) concentration among 28 landraces, improved varieties and advanced breeding lines of rice using candidate gene specific primers. Field evaluation of the experimental material was conducted in randomized block design with three replications and Zn content in unpolished grains of the entries was determined by addition of nitric acid and perchloric acid (1:3) following the procedure of diacid digestion method. Statistical analysis revealed the exploitable extent of variability with respect to grain Zn concentration among the entries. Eighteen entries were selected from the two extremes of grain Zn distribution range and subjected to molecular profiling using a panel of 14 candidate genes specific 12 reported and 14 designed primer pairs. Only eight (OsZIP1-1, OsZIP3a, OsZIP4a, OsZIP5-3, OsZIP7-2, OsZIP8b, OsNRAMP7 and OsNAAT1) reported and eight (OsZIP3K, OsZIP4K, OsZIP5K, OsZIP7K, OsNRAMP7K, OsNAAT1K, OsNACK and OsYSL14K) designed primers generated polymorphic amplified products showing sequence length variation due to targeted amplification of candidate genes specific genomic regions. Ample genetic differentiation and divergence were revealed among the entries, which were accommodated into similarity coefficient-based six clusters, remarkably consistent with grain Zn concentration of the entries. Hierarchical classification pattern of entries was almost completely corroborated by principal co-ordinate analysis based spatial distribution pattern of their genetic profiles. Molecular analysis based on candidate genes specific primers appeared to be an efficient approach for the elucidation of genetic differentiation and divergence in relation to variation of grain Zn concentration among entries. Hence, these markers can be effectively and efficiently utilized for grain Zn concentration related discrimination of rice genotypes and selection of parental genotypes for grain Zn biofortification. Microsatellites were detected within the candidate genes and amplicons, thereby providing a basis to deduce that the repeat sequence length variation in candidate genes may be a role player in the differential grain Zn accumulation in rice varieties. Single marker analysis established the association of OsNACK, OsZIP1-1, OsNRAMP7 and OsNRAMP7K with grain Zn concentration. Thus, these four markers can be effectively used in marker-assisted selection programme for grain Zn biofortification in rice.

Combined zinc and nitrogen applications at panicle initiation for zinc biofortification in rice

Background and purpose: Increasing zinc (Zn) concentration in rice grains can help improve Zn nutrition of people. The combinations of Zn and nitrogen (N) applications at panicle initiation were investigated for Zn biofortification in rice. Materials and methods: Rice (cv. Super Basmati) seedling were grown in pots having a calcareous soil. All possible combinations of four Zn (control, Soil 6 mg Zn kg–1, foliar 2 × 0.2% Zn and soil + foliar Zn) and three N (control, soil 20 mg N kg–1 and foliar 0.5% N) levels were imposed at panicle initiation. At maturity, grains were analysed for Zn and proteins. Results: Grain protein concentration was significantly increased with foliar Zn treatments, and with soil and foliar N. Maximum grain Zn concertation (30 mg kg–1) was achieved with application of soil Zn + foliar Zn + foliar N. At each N level, Zn application by either method significantly increased grain Zn concentration over control. This increase in grain Zn concertation at N levels was 36 to 54% with soil Zn + foliar Zn, 27 to 45% with foliar Zn and 9 to 15% with soil Zn over its control level. Conclusions: Grain Zn concentration was significantly increased with soil N when combined with soil Zn, and with foliar N when combined with foliar Zn treatments. Conclusively, foliar N combined with soil + foliar Zn is the best combination of late Zn and N application for agronomic Zn biofortification in rice.

Agronomic biofortification of rice (Oryza sativa L.) with selenium and its effect on element distributions in biofortified grains

Taking into account the relevance of biofortification of crop plants with selenium (Se) - an essential element for humans and animals -, this study assessed the effect of adding Se in the soil (as selenate) on: i) rice grains yield; ii) Se contents in polished rice grains; iii) physiological traits in rice leaves; and, iv) spatial distribution of Se and other elements in biofortified grains. A field trial was conducted using five Se rates (12, 21, 38, 68, and 120 g ha−1). Physiologic and enzymatic evaluations were carried out in rice leaves. Rice grain yield and Se contents were assessed. Spatial distributions of Se and other elements were visualized mapping the biofortified rice grains with μXRF at Brazilian Synchrotron Light Source. Results showed that soil Se application was effective in producing rice grains with higher Se contents, yet no effects were verified on rice yield. Antioxidant enzyme activities and gas exchanges in rice leaves changed following the application of Se. The spatial distribution of different elements in biofortified grains varied, with Se being accumulated mainly in the rice endosperm. Our results suggest that soil application of 47 and 36 g ha−1 of Se (as sodium selenate) may guarantee the production of rice grains with adequate Se levels for human consumption in Brazil and worldwide, respectively.

Zinc and Iron Nutrition Status in the Philippines Population and Local Soils.

The Philippines is one of the major rice-producing and rice-consuming countries of Asia. A large portion of its population depends on rice for their daily caloric intake and nutritional needs. The lack of dietary diversity among poor communities has led to nutritional consequences, particularly micronutrient deficiencies. Iron-deficiency anemia (IDA) and zinc deficiency (ZnD) are two serious nutritional problems that affect the health and economic sector of the country. Since rice dominates the Filipino diet by default, biofortification of rice will help improve the micronutrient status. The Philippine government has proactively initiated various programs and policies to address micronutrient deficiencies, particularly through fortification of basic food commodities. Biofortification, the fortification of rice with micronutrients through breeding, is considered the most sustainable and cost-effective strategy that can benefit large vulnerable populations. However, developing promising genotypes with micronutrient-enriched grains should be coupled with improving micronutrient bioavailability in the soil in order to optimize biofortification. This review documents the prevailing soil Zn-deficiency problems in the major rice production areas in the Philippines that may influence the Zn nutritional status of the population. The article also reports on the biofortification efforts that have resulted in the development of two biofortified varieties approved for commercial release in the Philippines. As nutritional security is increasingly recognized as a priority area, greater efforts are required to develop biofortified rice varieties that suit both farmers' and consumers' preferences, and that can address these critical needs for human health in a sustainable and cost-effective manner.

Iron biofortification in rice: in search of morphological traits for indirect selection in breeding programs

Iron (Fe) deficiency is an important cause of health concern in developing countries, demanding mitigation strate­gies to fight this disorder. The biofortification of staple foods, such as rice ( Oryza sativa L.), could be achieved via the development of improved cultivars. Iron quantification is relatively costly and time-consuming, making its rou­tine use impracticable in breeding programs. Therefore, the identification of traits to be used in indirect selection strategies would be of high interest. This study aimed to find promising traits for use in indirect selection programs aiming Fe biofortification in rice grains. A diverse set of 95 rice genotypes, mostly Brazilian, was grown at South­ern Brazil, in 2016/2017, and Fe content in brown and polished grains, as well as other 12 morphological traits, were assayed. Analysis of variance, linear correlation, and path analysis were carried out. Different levels of asso­ciation between traits were found, being panicles per plant and caryopsis width the most promising for use in indi­rect selection aiming increased Fe content in both brown and polished rice. However, secondary traits, such as caryopsis length, have also to be considered when performing selection aiming Fe biofortification in the cereal.

Accumulation, mobilization, and transformation of selenium in rice grain provided with foliar sodium selenite.

Selenium is an indispensable trace element for humans and its deficiency can lead to serious health complications. Nearly 70% of the area of China faces selenium deficiency. To deal with this problem, selenium-enriched rice has been increasingly incorporated into everyday diets. However, there is a lack of in-depth studies of the absorption, translocation, and transformation of selenium in the different parts of the rice plant when sprayed with sodium selenite. Foliar sodium selenite applied at critical growth stages can significantly improve the total and organic selenium content of plants. Application of 10 mg L-1 sodium selenite led to the most organic selenium (0.03 mg kg-1 ) in polished rice. Correlation studies of sodium selenite applied to leaves and other plant parts showed that total selenium accumulated most in glume, followed by rice bran, then polished rice, and finally embryo. The behavior of organic selenium was different. Organic selenium accumulated most in polished rice, then embryo, then rice bran, and finally glume. Moreover, 75-85% of the Se found in polished rice and embryo was organic in nature. We propose that 10 mg L-1 sodium selenite can be recommended as appropriate for foliar fertilization in the organic selenium biofortification of Se-free rice. © 2018 Society of Chemical Industry.

Molecular processes in iron and zinc homeostasis and their modulation for biofortification in rice.

More than a billion people suffer from iron or zinc deficiencies globally. Rice (Oryza sativa L.) iron and zinc biofortification; i.e., intrinsic iron and zinc enrichment of rice grains, is considered the most effective way to tackle these deficiencies. However, rice iron biofortification, by means of conventional breeding, proves difficult due to lack of sufficient genetic variation. Meanwhile, genetic engineering has led to a significant increase in the iron concentration along with zinc concentration in rice grains. The design of impactful genetic engineering biofortification strategies relies upon vast scientific knowledge of precise functions of different genes involved in iron and zinc uptake, translocation and storage. In this review, we present an overview of molecular processes controlling iron and zinc homeostasis in rice. Further, the genetic engineering approaches adopted so far to increase the iron and zinc concentrations in polished rice grains are discussed in detail, highlighting the limitations and/or success of individual strategies. Recent insight suggests that a few genetic engineering strategies are commonly utilized for elevating iron and zinc concentrations in different genetic backgrounds, and thus, it is of great importance to accumulate scientific evidence for diverse genetic engineering strategies to expand the pool of options for biofortifying farmer-preferred cultivars.

Down regulation of a heavy metal transporter gene influences several domestication traits and grain Fe-Zn content in rice

Biofortification of rice (Oryza sativa L.) would alleviate iron and zinc deficiencies in the target populations. We identified two alleles 261 and 284 of a Gramineae-specific heavy metal transporter gene OsHMA7 by analyzing expression patterns and sequences of genes within QTLs for high Fe & Zn, in Madhukar x Swarna recombinant inbred lines (RILs) with high (HL) or low (LL) grain Fe & Zn. Overexpression of 261 allele increased grain Fe and Zn but most of the transgenic plants either did not survive or did not yield enough seeds and could not be further characterized. Knocking down expression of OsHMA7 by RNAi silencing of endogenous gene resulted in plants with altered domestication traits such as plant height, tiller number, panicle size and architecture, grain color, shape, size, grain shattering, heading date and increased sensitivity to Fe and Zn deficiency. However, overexpression of 284 allele resulted in transgenic lines with either high grain Fe & Zn content (HL-ox) and tolerance to Fe and Zn deficiency or low grain Fe & Zn content (LL-ox) and phenotype similar to RNAi-lines. OsHMA7 transcript levels were five-fold higher in the HL-ox plants whereas LL-ox and RNAi plants showed 2–3 fold reduced levels compared to Kitaake control. Spraying LL-ox and RNAi lines with Fe & Zn at grain filling stage resulted in increased grain yield, significant increase in Fe & Zn content and brown pericarp. Altered expression of OsHMA7 influenced transcript levels of iron-responsive genes indicating cellular Fe-Zn homeostasis and also several domestication-related genes in rice. Our study shows that a novel heavy metal transporter gene influences yield and grain Fe & Zn content and has potential to improve rice production and biofortification.

Identification of genomic regions associated with agronomic and biofortification traits in DH populations of rice

Rice provides energy and nutrition to more than half of the world’s population. Breeding rice varieties with the increased levels of bioavailable micronutrients is one of the most sustainable approaches to tackle micronutrient malnutrition. So, high zinc and iron content in the grain are primary targets in rice biofortification breeding. In this study, we conducted QTL mapping using doubled haploid (DH) populations, PSBRc82 x Joryeongbyeo and PSBRc82 x IR69428, phenotyped for agronomic traits and micronutrients during two growing seasons and using genotypic information from analysis with the 6K SNP chip. A number of DH lines were identified as having high grain Zn and Fe content in polished rice. Importantly, we identified 20 QTLs for agronomic traits and 59 QTLs for a number of biofortification traits. Of the 79 QTLs, 12 were large-effect QTLs (>25% PVE), nine QTLs were consistent across seasons in either population, and one QTL was identified in both populations. Moreover, at least two QTLs were clustered in defined regions of chromosomes 1, 2, 3, 4, 5, 7 and 9. Eight epistatic interactions were detected for Cu, Mg, Na, and Zn in population 1. Furthermore, we identified several candidate genes near QTLs for grain Zn (OsNRAMP, OsNAS, OsZIP, OsYSL, OsFER, and OsZIFL family) and grain yield (OsSPL14 and OsSPL16). These new QTLs and candidate genes help to further elucidate the genetic basis for grain micronutrient concentration, and may prove useful for marker assisted breeding for this important trait.

Simultaneous Zinc and selenium biofortification in rice. Accumulation, localization and implications on the overall mineral content of the flour

Zinc (Zn) and selenium (Se) are essential mineral nutrients for humans, but their daily intake is often below adequate levels, particularly in developing countries. To increase these minerals amounts in the edible plant tissues, agronomic biofortification is an efficient strategy. Rice (Oryza sativa L.) is an important food crop, and a crucial source of mineral nutrients. Within the International Rice Research Institute (IRRI) program to guarantee food and nutritional security in Sub-Saharan Africa region, this work aims at evaluating Zn- and Se-biofortification capability of two Mozambican rice cultivars (Makassane and IR-87684-23-2-3-2), considering three Zn levels (0, 300, 600 g ha−1), and three Se levels (0, 150, 300 ha−1). Results showed that foliar Zn and Se application promoted higher accumulation of these minerals in the IR grains. Biofortification was more efficient in the whole grain than in polished grain, with mineral mapping images and quantification showing that Zn, Se, K, Ca, and S accumulation prevailed in the outer part of the grain irrespective of genotype. The 600 Zn and 150 Se g ha−1 dosage maximized Zn content in the flour, while provided Se values that reduced the Se antagonism with Zn, Ca, S and Mo. Still, Se doses can be lowered.

Correction: Transporter genes identified in landraces associated with high zinc in polished rice through panicle transcriptome for biofortification.

[This corrects the article DOI: 10.1371/journal.pone.0192362.].

Joint Exploration of Favorable Haplotypes for Mineral Concentrations in Milled Grains of Rice (Oryza sativa L.).

Grain minerals in rice, especially those in milled grains, are important sources of micro-nutrition elements, such as iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), and selenium (Se), and of toxic heavy metal elements, especially cadmium (Cd), for populations consuming a rice diet. To date, the genetic mechanism underlying grain mineral concentrations (GMCs) in milled grain remains largely unknown. In this report, we adopted a set of 698 germplasms consisting of two subsets [indica/Xian (X-set) and japonica/Geng (G-set)], to detect quantitative trait loci (QTL) affecting GMC traits of Fe, Zn, Cd, Mn, Cu, and Se in milled grains. A total of 47 QTL regions, including 18 loci and 29 clusters (covering 62 Cd loci), responsible for the GMCs in milled grains were detected throughout the genome. A joint exploration of favorable haplotypes of candidate genes was carried out as follows: (1) By comparative mapping, 10 chromosome regions were found to be consistent with our previously detected QTL from linkage mapping. (2) Within eight of these regions on chromosomes 1, 4, 6, 7, and 8, candidate genes were identified in the genome annotation database. (3) A total of 192 candidate genes were then submitted to further haplotype analysis using million-scale single nucleotide polymorphisms (SNPs) from the X-set and the G-set. (4) Finally, 37 genes (19.3%) were found to be significant in the association between the QTL targeting traits and the haplotype variations by pair-wise comparison. (5) The phenotypic values for the haplotypes of each candidate were plotted. Three zinc finger (like) genes within two candidate QTL regions (qFe6-2 and qZn7), and three major GMC traits (Fe, Zn, and Cd) were picked as sample cases, in addition to non-exhausted cross validations, to elucidate this kind of association by trait value plotting. Taken together, our results, especially the 37 genes with favorable haplotype variations, will be useful for rice biofortification molecular breeding.

Selenium biofortification of rice grains and implications on macronutrients quality

Selenium is an essential element for human health but its intake is low. Accordingly, biofortified rice with this trace element can be prophylactic to consumers. In this context, this study aimed to develop an agronomic itinerary for rice biofortification with selenium, considering sodium selenite and selenate as foliar fertilizers. Since both forms of selenium fertilizers have different metabolic specificity among genotypes, the implications on sugars, fatty acids and proteins quality were also assessed. Biofortification was performed in field trials, in four target genotypes, applying both foliar fertilizers with concentrations ranging between 0 and 300 g Se ha−1. It was found that biofortification with sodium selenite caused, relatively to sodium selenate, a higher accumulation of selenium in the grain. Application of high concentrations of sodium selenite and selenate increased total lipids in all the genotypes, mostly oleic acid (C18:1), linoleic (C18:2) and palmitic acid (C16:0). Sugars (with the concentration pattern being sucrose > glucose > raffinose > fructose) and proteins showed a similar trend. It is concluded that biofortification of crops with selenium is more effective with 120–300 g Se ha−1, but macronutrients quality in the flour varies significantly within rice genotypes.

Transporter genes identified in landraces associated with high zinc in polished rice through panicle transcriptome for biofortification.

Polished rice is poor source of micronutrients, however wide genotypic variability exists for zinc uptake and remobilization and zinc content in brown and polished grains in rice. Two landraces (Chittimutyalu and Kala Jeera Joha) and one popular improved variety (BPT 5204) were grown under zinc sufficient soil and their analyses showed high zinc in straw of improved variety, but high zinc in polished rice in landraces suggesting better translocation ability of zinc into the grain in landraces. Transcriptome analyses of the panicle tissue showed 41182 novel transcripts across three samples. Out of 1011 differentially expressed exclusive transcripts by two landraces, 311 were up regulated and 534 were down regulated. Phosphate transporter-exporter (PHO), proton-coupled peptide transporters (POT) and vacuolar iron transporter (VIT) showed enhanced and significant differential expression in landraces. Out of 24 genes subjected to quantitative real time analyses for confirmation, eight genes showed significant differential expression in landraces. Through mapping, six rice microsatellite markers spanning the genomic regions of six differentially expressed genes were validated for their association with zinc in brown and polished rice using recombinant inbred lines (RIL) of BPT 5204/Chittimutyalu. Thus, this study reports repertoire of genes associated with high zinc in polished rice and a proof concept for deployment of transcriptome information for validation in mapping population and its use in marker assisted selection for biofortification of rice with zinc.

Progress in ZIP transporter gene family in rice.

Zinc and iron are essential mineral elements for the growth of Oryza sativa L. and also micronutrients for human health. Therefore, it is vital to study biofortification of rice with Zn and Fe in order to improve the yield and quality of rice, as well as to enhance nutritional states of humans. The zinc-regulated transporters and iron-regulated transporter-like proteins (the ZIP family) control the absorption and translocation of Zn and Fe and maintain their homeostasis in rice. Reciprocally, the expression of the ZIP family is induced by the concentration of Zn and Fe. There are abundant natural allelic variations of the ZIP genes, and some haplotypes only occur in indica or japonica, which could affect Zn and Fe accumulation levels between these subspecies. Currently, emerging functional studies of the accumulation mechanism of Zn and Fe in grains reveal that a lot still needs to be learned about the allele variations of ZIP genes. In fact, only OsZIP3 is functional characterized. In this review, we summarize the latest progress in the molecular characteristics of the ZIP transporters, including protein localization, gene expression patterns, transport mechanism, metal ion interaction, and natural allelic variations.

Agronomic biofortification of upland rice with selenium and nitrogen and its relation to grain quality

The objective of the present study was to evaluate agronomic biofortification with nitrogen (N) and selenium (Se) with the aim of increasing the daily Se intake by the population and the nutritional quality of the grain. A randomized block experimental design with a 5 × 2 factorial scheme was used; the factors were the five levels of N (0, 20, 40, 80, and 120 kg ha−1), applied as topdressing fertilization, and the two levels of Se (0 and 25 g ha−1). The reserve protein fractions in the seeds, glutelin, and globulin increased significantly when Se application was combined with N fertilization. Grain Se content varied from 0.03 to 0.35 mg kg−1, which was within the food safety limit of 0.3 mg kg−1 established by the Codex Alimentarius. The estimated daily Se intake originating from Se-biofortified rice varied between 2.05 and 24.7 μg per day, representing an increase from 3.72% to 44.9% of the daily Se requirement. Because the recommended Se daily intake for adults is 55 μg per day, the present study presents relevant information about agronomic biofortification to increase Se concentrations in edible plant parts, with possible benefits to human health.

How Could Agronomic Biofortification of Rice Be an Alternative Strategy with Higher Cost-Effectiveness for Human Iron and Zinc Deficiency in China?

Iron and zinc deficiencies affect human health globally, especially in developing countries. Agronomic biofortification, as a strategy for alleviating these issues, has been focused on small-scale field studies, and not widely applied while lacking of cost-effectiveness analysis (CEA). We conducted the CEA of agronomic biofortification, expressed as USD per disability-adjusted life years (DALYs) saved, to recommend a cost-effectiveness strategy that can be widely applied. The DALYs were applied to quantify the health burden due to Fe and/or Zn deficiency and health cost of agronomic biofortification via a single, dual, or triple foliar spray of Fe, Zn, and/or pesticide in 4 (northeast, central China, southeast, and southwest) major Chinese rice-based regions. The current health burden by Fe or Zn malnutrition was 0.45 to 1.45 or 0.14 to 0.84 million DALYs for these 4 regions. Compared to traditional rice diets, the daily Fe and/or Zn intake from Fe and/or Zn-biofortified rice increased, and the health burden of Fe and/or Zn deficiency decreased by 28% and 48%, respectively. The cost of saving 1 DALYs ranged from US$376 to US$4989, US$194 to US$2730, and US$37.6 to US$530.1 for the single, dual, and triple foliar Fe, Zn, and/or pesticide application, respectively, due to a substantial decrease in labor costs by the latter 2 applications. Agronomic biofortification of rice with the triple foliar spray of Fe, Zn, and pesticide is a rapidly effective and cost-effectiveness pathway to alleviate Fe and Zn deficiency for rice-based dietary populations.