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Selenium (Se) and zinc (Zn) deficiencies have become serious global food security and public health problems. Biofortification through foliar fertilizer is a nonspecific, low-tech, and cost-effective strategy. Se and Zn have overlapping physiological roles and interacting relationships in plants. Mung bean is superior for Se enrichment and an excellent Zn carrier. However, the molecular mechanism underlying the interaction between Se and Zn in the mung bean remains unclear. Herein, Se and Zn accumulation, antioxidant activities, physiological determination, and transcriptomic analysis were performed under both Se and Zn treatments. Common essential roles of Se and Zn in mung bean were reflected by the comprehensively altered ten physiological indexes under both Se2 (24 g·ha -1 ) and Zn1 (1.2 kg·ha -1 ) treatments. Overlapping transcriptome changes and common DEGs in two compared groups revealed that the upregulated expression of sulfate transporters (SULTRs), phosphate transporters (PHTs), and Zinc-regulated/Iron-regulated-like protein (ZIP) family genes under Se and Zn treatments directly promoted both Se and Zn intakes. Furthermore, the altered Se/Sulfur, nitrogen, and carbohydrate metabolisms are closely interlinked with the uptake and assimilation of Se and Zn via the 20 key genes that we filtered through the protein-protein interaction (PPI) network analysis. Further analysis indicated that l-methionine γ-lyase (E 4.4.1.11) genes may play an important role in the transamination of selenomethionine and its derivatives; glutamine synthetase (GS), nitrate reductase (NR), and starch synthase (SS) genes may regulate the nitrogen assimilation and carbohydrate metabolism, which provide more carriers for Se and Zn; glutathione peroxidase (GPx), glutamate-cysteine ligase catalytic subunit (GCLC), and serine acetyltransferase (SAT) genes may accelerate the GSH-GSSH cycle and promote Se and Zn storages. This study provides new molecular insights into the comprehensive improvement of the nutritional quality of mung beans in Se and Zn biofortification productions.

Zinc (Zn) plays a crucial role in metabolism in both plant and animal life. Zn deficiency is a worldwide problem that has recently gotten worse. This micronutrient shortage can be largely attributed to eating foods that are poor in zinc. If biofortification methods were widely used, Zn enrichment of the organ or tissue of interest would increase dramatically. However, Zn absorption mechanisms in rice plants must be understood on a fundamental level before these methods can be used effectively. Plant systems' Zn transporters and metal chelators play a major role in regulating this intricate physiological characteristic. The Zn efficiency of specific species is affected by a variety of factors, including the plant's growth stage, edaphic conditions, the time of year, and more. Both old and new ways of breeding plants can be used for biofortification. We have highlighted the significance of recombinant and genetic approaches to biofortifying in rice. In this review, we have the metabolic role of zinc in rice, and the different transporter families involved in the transportation of zinc in rice. We have also discussed the combined approaches of agronomic and genetic in zinc biofortification in rice and potential outcomes and future predictions., Competing Interests: Declaration of competing interest All the authors declare no conflict of interest., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

This study aimed to evaluate the potential of zinc oxide nanoparticles (ZnO NPs) in the biofortification of lentil seedlings and subsequently improve the Zn status in rats. In the first phase of the study, the effects of various ZnO NPs concentrations (0, 10, 20, 40, 80, and 160 ppm) on the lentil growth, Zn accumulation, and other physiological parameters were investigated. Subsequently, the rats were fed ZnO NP-biofortified lentil seedlings (20 and 160 ppm) to assess their impact on animal health and Zn status. The results highlighted a concentration-dependent response of lentil seedlings to ZnO NPs, with optimal growth observed at 20 ppm, whereas higher concentrations inhibited lentil growth. Pigment and biochemical analyses revealed a complex interplay between chlorophyll, carotenoids, soluble sugars, and proteins with distinct responses to nanoparticle concentrations. Elevated levels of hydrogen peroxide and malondialdehyde of lentil seedlings at high concentrations of ZnO NPs suggest oxidative stress, countered by the upregulation of antioxidant enzymes and increased phenolic compounds. On the other hand. animal studies have showed that ZnO NP-biofortified lentil seedlings enhance serum zinc and magnesium levels in rats without affecting body weight. While serum triglyceride levels of rats decreased in both treatment groups, an elevation in creatinine and a marked increase in aspartate aminotransferase (AST) levels were observed at a higher ZnO NP concentration (160 ppm), indicative of potential kidney and liver stress. Paradoxically, serum iron levels were lower in all groups consuming lentil seedlings than in the control group, suggesting a potential interaction between lentil components and iron metabolism. These findings suggest that ZnO NP-biofortified lentils may be a promising approach to enhance Zn nutrition; however, further investigation is needed to optimize ZnO NPs concentration and assess long-term safety., (© 2024. The Author(s).)

Micronutrient deficiencies are a critical factor in the development of obesity. This work aimed to determine the Se and Zn bioaccessibility on biofortified chickpea flour and evaluate their impact on the antioxidant and anti-inflammatory activities. The greatest increase (235 %) in isoflavones was observed in the ZnSO 4 -treatment compared to the control. Malonylated-formononetin-glucoside was the major isoflavone (43 %-50 %) found in the treatments. Na 2 SeO 3 -treated seeds showed the highest Se accumulation, while the greatest Zn accumulation was found in ZnSO 4 -treated seeds. Se bioaccesibility followed the order: Germinated Control>ZnSO 4  > ZnSeO 3  > ZnSO₄ + Na 2 SeO 3  > Na 2 SeO 3, while in the seeds biofortified with Zn salts showed the order: Germinated Control>ZnSeO 3  > ZnSO₄ + Na 2 SeO 3  > Na 2 SeO 3  > ZnSO 4 . All treatments showed antioxidant activity. Na 2 SeO 3 -treatment (15.625 μg/mL) showed a significant reduction of 52 % in NO production compared to the Germinated Control. These findings demonstrated the biological value of food biofortification in providing minerals in the diet to combat the oxidative stress characteristic of obesity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Zinc (Zn) content is of great importance in healthy human diet, crop productivity and stress tolerance in soils with zinc deficiency. The genes used to increase yield per unit area such as semi-dwarf 1 ( sdw1 ) is commonly considered to reduce mineral content of grain., Methods: In the present study, influence of sdw1.d , a widely used allele for short plant height in barley breeding, on zinc accumulation and tolerance to zinc deficiency were investigated. A near isogenic line of sdw1.d allele, its recurrent parent Tokak 157/37 and donor parent Triumph were grown in zinc-deficient and-sufficient hydroponic cultures. Two experiments were conducted until heading stage and physiological maturity., Results: In zinc-deficient conditions, sdw1.d allele increased shoot dry weight by 112.4 mg plant -1 , shoot Zn concentration by 0.9 ppm, but decreased root Zn concentration by 6.6 ppm. It did not affect grain characteristics, but increased grain Zn content. In zinc-sufficient conditions, sdw1.d allele increased shoot Zn content, and decreased root Zn content. sdw1.d did not affect grain weight but increased grain Zn concentration by about 30% under zinc-sufficient conditions. The results showed that sdw1.d allele has no negative effect on tolerance to zinc deficiency, and even promotes tolerance to zinc deficiency by more Zn translocation. It was revealed that sdw1.d allele improves Zn accumulation under both zinc-deficient and zinc-sufficient condition. The sdw1.d allele could contribute to solving the problems in plant growth and development caused by zinc-deficiency via improving tolerance to zinc-deficiency. It could also provide a better Zn biofortification., Competing Interests: The author declare that I have no competing interests., (© 2024 Saygili.)

Background: South, East, and Southeast Asia are among the 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 can potentially improve zinc intake, especially among the most vulnerable., Objectives: We modeled the impact of the consumption of zinc-biofortified rice on zinc intake and inadequacy among women of childbearing age and young children nationally in Indonesia, the Philippines, and at a subnational 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 3 countries, the prevalence of dietary zinc inadequacy at baseline was 94%-99% among women of childbearing age, 77%-100% among children 4-5 y old, and 27%-78% among children 1-3 y old. At the current breeding target of 28 ppm, zinc-biofortified rice has the potential to decrease zinc inadequacy by ≤50% among women and children in rural Bangladesh and among children in the Philippines where consumption of rice is higher compared with Indonesia., Conclusions: Our analysis shows that increasing zinc content in rice ≤45 ppm reduces the burden of zinc inadequacy substantially, after which we encourage programs to increase coverage to reach the highest number of beneficiaries., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Zinc (Zn) deficiency in humans is of worldwide concern. The objective of this study was to investigate the Zn intake gap in Chinese adults and identify the potential role of biofortification technologies for wheat and rice, including crop nutrient management and breeding, in filling the gap., Results: We use data from the China Health and Nutrition Survey in 2011 to identify food consumption patterns and dietary Zn intake of 4512 adults to define and quantify the Zn intake gap in the population. The dietary Zn intake gap of surveyed adults ranged from -0.8 to 6.53 mg day -1 across nine provinces and differences were associated with differences in food consumption patterns. Both dietary Zn intake and Zn gap for males were higher than for females. The potential of changes in five management strategies (improved nitrogen fertilization, improved phosphorus fertilization, foliar Zn fertilization, improved water management and growing varieties reaching the grain Zn breeding target) was analyzed. Breeding and foliar Zn fertilization were shown to be the two most effective management strategies that could increase dietary intake by 1.29 to 5 mg Zn day -1 dependent on sex and province., Conclusion: This study shows that the Zn gap varied across regions in China, with some large enough to warrant interventions. Wheat and rice as two major Zn sources could be targeted without a direct need for dietary diversification. By promoting both biofortification breeding of wheat and rice and Zn fertilization, dietary Zn intake could be enhanced to contribute to human health improvement in China. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Zinc (Zn) deficiency is a worldwide problem, and this review presents an overview of the magnitude of Zn deficiency with a particular emphasis on present global challenges, current recommendations for Zn intake, and factors that affect dietary requirements. The challenges of monitoring Zn status are clarified together with the discussion of relevant Zn bioaccessibility and bioavailability issues. Modern lifestyle factors that may exacerbate Zn deficiency and new strategies of reducing its effects are presented. Biofortification, as a potentially useful strategy for improving Zn status in sensitive populations, is discussed. The review proposes potential actions that could deliver promising results both in terms of monitoring dietary and physiological Zn status as well as in alleviating dietary Zn deficiency in affected populations.

Background: Increasing the concentration of zinc (Zn) in a widely consumed staple food, such as Chinese steamed bread (CSB), is a promising strategy for alleviating Zn malnutrition in humans. The aim of this study, which was based on a 2-year field experiment, was to evaluate the effectiveness of spraying Zn fertilizer combined with commonly applied (i) pesticides and/or (ii) KH 2 PO 4 (PK) to increase the concentration of Zn and its bioavailability in wheat grain and the CSB derived from it., Results: All the foliar Zn applications (foliar Zn alone or combined with pesticides and PK) significantly increased the concentration of Zn in grain and derived CSB by 69.1% and 63.1%, respectively. Milling caused an 86-88% loss of Zn, while the process of producing CSB caused an 11-26% increase in the concentration of Zn. A net gain of 2.5-8.3 mg Zn kg -1 of CSB was achieved owing to foliar applications of Zn. The concentration of phytic acid (PA) decreased dramatically during milling (89-90%) and the production of CSB (69-72%). As a result, the Zn bioavailability was greater in the CSB than in grain. Foliar applications of Zn also increased the estimated Zn bioavailability of CSB to be as high as 5.5-7.8 mg, which is adequate for human nutrition. Enrichment with Zn had no adverse effects on the quality of CSB., Conclusion: The mixture of foliar Zn with pesticides and PK represents a useful approach to improve the bioavailable Zn of CSB without altering its quality. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

A pot experiment was conducted in an open greenhouse to explore the use of citrate-coated cobalt ferrite nanoparticles (CoFe 2 O 4 NPs) as a source for Fe fortification of three wheat lines ( Triticum aestivum L.). Two of the three wheat lines tested differ in their efficiency concerning Zn storage in their grains (efficient and inefficient), and one had inefficient P-absorption. The NPs were supplied by foliar or soil application of Fe at 330 mg L -1 , and 46 or 68 mg kg -1 soil, respectively. A positive control (Fe-EDTA salt, a conventional iron fertilizer) and a negative control (no fertilization) were also included to compare the efficiency of NP fertilization. Soil fertilization with NPs improved the grain yield and Fe concentration in the grains compared with the foliar application of NPs and conventional Fe fertilizer. Application of soil NPs at 68 mg kg -1 increased the grain yield by 52% and 21% compared with the control and soil Fe-EDTA treatments, respectively. Likewise, grain Fe concentration increased by 96% and 72% compared with the control and soil Fe-EDTA treatments, respectively. The phytic acid concentration in grains and the phytic acid:Fe ratio decreased by 6% and 62%, respectively, due to the soil application of NPs (68 mg Fe per kg). The Fe grain concentration of lines inefficient for Zn storage and P-uptake in plants from soil fertilized with NPs (68 mg Fe per kg) was 1.37 and 0.26 fold above the target biofortification concentration (60 mg Fe per kg). Cobalt concentration in grains ranged from 9 to 16 mg kg -1 . These concentrations were below the maximum allowable limit of Co in grains (50 mg kg -1 ) recommended by FAO and the WHO. Our results showed that Fe supplied as NPs may improve the nutritional quality of wheat grains, and the economic yield. However, there remains a long way to go to achieve effective and economic use of nanotechnology for the nutritional development of wheat.

Background: Wheat is a staple cereal food around the globe. It provides a significant source of proteins, carbohydrates, and other micronutrients to humans. When grown on cadmium (Cd) contaminated soils, the uptake of trace elements e.g ., iron (Fe) and zinc (Zn) has also been affected drastically that in turn affected the wheat grain., Methods: In this study, wheat accessions were used to investigate the impact of soil application of Zn (5 mg/kg, 20 mg/kg) and Cd (0 mg/kg, 10 mg/kg) on accumulation of these elements in wheat grains. A total of 45 Fe, Zn, and Cd transporter-related genes were used to design 101 gene-specific SSR (simple sequence repeat) markers., Results: In response to Cd stress, application of 20 mg/Kg Zn improved Fe (64.6 ug/g) and Zn (48.3 ug/g) accumulation in wheat grains as well as agronomic traits. Marker trait association revealed that SSR markers based on NAM-B1 gene (PR01 and PR02) were associated with Zn accumulation. Similarly, SSR markers based on TaVTL5-2B_5 (PR19 PR20), TaVTL5-2B_2 (PR25, PR26), TaVTL5-2D_3 (PR30), TaVTL2-2A (PR31), TaVTL1-6A (PR32), and TaVTL2-2D_1 (PR37) were significantly associated with Fe accumulation, while HMA3-5B1 (PR62) and TaNRAMP3-7D (PR89) were linked to Cd accumulation in grains. The highly associated markers may be used in marker-assisted selection of suitable wheat genotypes for breeding bio-fortified varieties with low Cd accumulation., Competing Interests: Farrukh Azeem is an Academic Editor for PeerJ., (© 2023 Rasheed et al.)

Many developing countries are facing a silent increase in deficiency of micronutrients in forage crops that results in decreased levels of essential nutrients in animals. Micronutrients are essential not only for basic metabolic processes of forage crops but also for sustaining animal health. Forage productivity and quality are severely affected by soil micronutrients deficiencies, especially zinc and copper. This review summarizes the literature highlighting the significance of different methodologies used to increase the biomass and quality of forage so as to enhance the micronutrient content of the forage crops through biofortification. Biofortification is a promising and sustainable agriculture-based strategy to reduce micronutrient deficiency in crops. The experiments and trials conducted at different locations of the world showed that copper and zinc concentrations in animal fodders can be enhanced through the process of foliar application. Additionally, agronomic biofortification showed more promising results, and thus is an outstanding, fast, and cost-effective technique for the immediate enrichment of forage in order to overcome malnutrition in animals. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)

Over three billion people suffer from various health issues due to the low supply of zinc (Zn) and iron (Fe) in their food. Low supply of micronutrients is the main cause of malnutrition and biofortification could help to solve this issue. Understanding the molecular mechanisms of biofortification is challenging. The membrane transporters are involved in the uptake, transport, storage, and redistribution of Zn and Fe in plants. These transporters are also involved in biofortification and help to load the Zn and Fe into the endosperm of the seeds. Very little knowledge is available on the role and functions of membrane transporters involved in seed biofortification. Understanding the mechanism and role of membrane transporters could be helpful to improve biofortification. In this review, we provide the details on membrane transporters involved in the uptake, transport, storage, and redistribution of Zn and Fe. We also discuss available information on transporters involved in seed biofortification. This review will help plant breeders and molecular biologists understand the importance and implications of membrane transporters for seed biofortification., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Biofortified foods are a new approach to increase minerals in the diet, and evidence suggests that zinc (Zn) biofortification can improve Zn physiological status in humans. This systematic review aimed to answer the question: "What are the effects of the consumption of Zn biofortified foods on Zn status in humans?". This review was conducted according to PRISMA guidelines and registered in PROSPERO (CRD42021250566). PubMed, Cochrane, Scopus and Science Direct databases were searched for studies that evaluated the effects of Zn biofortified foods on Zn absorption. Of 4282 articles identified, nine remained after inclusion/exclusion criteria were applied. Limitations in study quality, external and internal validity (bias/confounding), and study power were evaluated. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was used to assess the certainty of evidence. Of the nine articles included, five observed an increase in total Zn absorption, and one showed that Zn participated in the conversion of linoleic acid to dihomo-γ-linolenic acid. By increasing the amount of Zn in the food, Zn biofortification can reduce the phytate:Zn molar ratio and improve Zn absorption in humans. More studies are needed to clarify what portion of Zn biofortified foods/day is needed to achieve a significant effect on Zn status.

Zinc, through its structural and cofactor roles, affects a broad range of critical physiological functions, including growth, metabolism, immune and neurological functions. Zinc deficiency is widespread among populations around the world, and it may, therefore, underlie much of the global burden of malnutrition. Current zinc fortification strategies include biofortification and fortification with zinc salts with a primary focus on staple foods, such as wheat or rice and their products. However, zinc fortification presents unique challenges. Due to the influences of phytate and protein on zinc absorption, successful zinc fortification strategies should consider the impact on zinc bioavailability in the whole diet. When zinc is absorbed with food, shifts in plasma zinc concentrations are minor. However, co-absorbing zinc with food may preferentially direct zinc to cellular compartments where zinc-dependent metabolic processes primarily occur. Although the current lack of sensitive biomarkers of zinc nutritional status reduces the capacity to assess the impact of fortifying foods with zinc, new approaches for assessing zinc utilization are increasing. In this article, we review the tools available for assessing bioavailable zinc, approaches for evaluating the zinc nutritional status of populations consuming zinc fortified foods, and recent trends in fortification strategies to increase zinc absorption.

Biofortification of wheat is potentially a sustainable strategy to improve zinc intake; however, evidence of its effectiveness is needed. A household-based, double-blind, cluster-randomized controlled trial (RCT) was conducted in rural Pakistan. The primary objective was to examine the effects of consuming zinc-biofortified wheat flour on the zinc status of adolescent girls aged 10−16 years (n = 517). Households received either zinc-biofortified flour or control flour for 25 weeks; blood samples and 24-h dietary recalls were collected for mineral status and zinc intake assessment. Plasma concentrations of zinc (PZC), selenium and copper were measured via inductively coupled plasma mass spectrometry and serum ferritin (SF), transferrin receptor, alpha 1-acid glycoprotein and C-reactive protein by immunoassay. Consumption of the zinc-biofortified flour resulted in a moderate increase in intakes of zinc (1.5 mg/day) and iron (1.2 mg/day). This had no significant effect on PZC (control 641.6 ± 95.3 µg/L vs. intervention 643.8 ± 106.2 µg/L; p = 0.455), however there was an overall reduction in the rate of storage iron deficiency (SF < 15 µg/L; control 11.8% vs. 1.0% intervention). Consumption of zinc-biofortified flour increased zinc intake (21%) but was not associated with an increase in PZC. Establishing a sensitive biomarker of zinc status is an ongoing priority.

Zinc-biofortified flour may be a cost-effective approach to improve zinc status of populations in low-resource settings. The success of biofortification programmes is subject to acceptability and uptake by consumers. This study explored community leaders' and community members' ( n = 72) experiences and attitudes towards the flour provided during a cluster randomised controlled trial of zinc biofortified wheat in rural Pakistan (BiZiFED2). Focus group discussions ( n = 12) were conducted and thematic analysis applied using an inductive, semantic, contextualist approach. Five themes were identified: (1) Contribution to food security; (2) Better sensory and baking properties than local flour; (3) Perceived health benefits; (4) Willingness to pay for the flour; and (5) Importance of trusted promoters/suppliers. Although the participants were blind to whether they had received control or biofortified flour, referred to collectively as "study flour", the results indicated that the study flour performed well in terms of its taste and bread making qualities, with no adverse reports from participants in either arm of the BIZIFED2 RCT. Participants suggested that they would buy the biofortified wheat if this was available at a fair price due to perceived health benefits, reporting positive sensory characteristics and cooking attributes when compared to the flour available in the local markets. Overall, there was a positive reception of the programme and flour among the participants, and members of the community hoped for its continuation and expansion.

Background: Zinc-biofortified rice could contribute to zinc intake in deficient populations, but processing it into parboiled rice could affect this potential benefit. Zinc and iron true retention (TR) in milled rice produced under conditions resembling household and commercial parboiled methods was evaluated. Zinc and iron TR in milled rice obtained from biofortified and non-biofortified rice subjected to different soaking temperatures during parboiling was also evaluated., Results: Conditions resembling commercial parboiling methods resulted in 52.2-59.7% zinc TR and 55.4-79.1% iron TR, whereas those used for household parboiling resulted in 70.7-79.6% zinc TR and 78.2-119.8% iron TR. Zinc TR in milled (8-16% bran removal) biofortified and non-biofortified parboiled rice was 50.6-66.8% when soaking rough rice at 20 °C and 29.9-56.0% when soaking rough rice at 65 °C; both had lower zinc TR than non-parboiled rice (58.0-80.6%). Iron TR was generally similar between milled non-parboiled and parboiled rice (26.2-67.6%) and between parboiled biofortified and non-biofortified milled rice., Conclusion: Parboiling conditions used to obtain milled rice targeted for own household consumption resulted in higher zinc and iron TR compared to parboiling conditions used for milled rice targeted for markets. More zinc from the inner endosperm moved towards the outer layers at high soaking temperature, resulting in lower zinc TR for milled parboiled rice soaked in hotter water. Parboiled rice soaked at temperatures used in households could provide more zinc to diets compared to rice soaked in hotter water commonly used in large rice mills, especially when rice is extensively milled. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Zinc plays many essential roles in life. As a strong Lewis acid that lacks redox activity under environmental and cellular conditions, the Zn 2+ cation is central in determining protein structure and catalytic function of nearly 10% of most eukaryotic proteomes. While specific functions of zinc have been elucidated at a molecular level in a number of plant proteins, wider issues abound with respect to the acquisition and distribution of zinc by plants. An important challenge is to understand how plants balance between Zn supply in soil and their own nutritional requirement for zinc, particularly where edaphic factors lead to a lack of bioavailable zinc or, conversely, an excess of zinc that bears a major risk of phytotoxicity. Plants are the ultimate source of zinc in the human diet, and human Zn deficiency accounts for over 400 000 deaths annually. Here, we review the current understanding of zinc homeostasis in plants from the molecular and physiological perspectives. We provide an overview of approaches pursued so far in Zn biofortification of crops. Finally, we outline a "push-pull" model of zinc nutrition in plants as a simplifying concept. In summary, this review discusses avenues that can potentially deliver wider benefits for both plant and human Zn nutrition., (Copyright © 2021 The Author. Published by Elsevier Inc. All rights reserved.)

Biofortification is a nutritional strategy used to enhance nutrients in a variety of staple foods. As bananas and plantains (Musa spp.) are considered staple food in many developing countries, monitoring zinc (Zn) content in biofortified bananas is crucial to ensure this mineral intake. Bananas were biofortified by injecting Zn sulfate heptahydrate (ZnSO 4 ·7H 2 O) solutions into banana trees' pseudostem (1%, 2%, and 4%) compared with the control treatment. Zinc content was estimated using energy-dispersive X-ray fluorescence (EDXRF) and multivariate calibration using partial least squares (PLS). The impressive result is the possibility of high throughput analysis of Zn in bananas after biofortification to guarantee the quality when eaten as a central portion of the diet., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Micronutrients deficiency in soil-plant and human is well-addressed; however, little is known about their spatial distribution, magnitude of deficiency and biological nexus. Zinc deficiency (ZnD) and iron-deficiency anemia (FeD) are two serious nutritional concerns which are negatively affecting human health. Herein, a survey-based case study was conducted in major wheat-based cropping system of east-central Pakistan. Soil and grain samples were collected from 125 field-grown wheat from 25 distinct sites/villages and GPS coordinates were taken for mapping. The collected samples were tags according to the names of 25 sites, i.e., UCs (union councils; an administrative unit). The quantified amount of zinc (Zn) or iron (Fe) in soil-wheat grains was compared with their recommended concentrations (RCZn, RCFe) for human nutrition. Additionally, clinical features of ZnD and FeD were diagnosed among local farmers who used to consume these grains, throughout the year, cultivated on their farm, and quantified their deficiency prevalence (ZnDP, FeDP). Results revealed, the collected 64% (0.54 to 5.25 mg kg -1 ) soils, and 96% (1.4 to 31 mg kg -1 ) grain samples are Zn-deficient (RCZn) along with ZnDP recorded among 68% of population. Meanwhile, FeD is quantified in 76% (1.86 to 15 mg kg -1 ) soil, 72% grain (2.1 to 134 mg kg -1 ) samples, and FeDP is found among 84% of studied population. A strong and positive correlation is developed in the Zn-or FeDP with their deficiencies in soil and grain by plotting multivariate analysis. In line with spatial distribution pattern, the UCs, namely, 141, 151, 159 and 132 are quantified severe deficient in Zn and Fe, and others are marginal or approaching to deficient level. Our findings rationalize the biological nexus of Zn and Fe, and accordingly, draw attention in the biofortification of staple crop as a win-win approach to combat the rising malnutrition concerns., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Biofortification is a novel method for improving the nutritional value of grains. Wheat is widely consumed worldwide. Thus, wheat zinc biofortification may improve the zinc status of populations., Objectives: We determined the effect of consuming zinc-biofortified wheat on plasma zinc concentrations and biomarkers of zinc-dependent functions in a controlled feeding study., Methods: Thirty-six healthy adult men, aged 18 to 51 y, participated in a 10-wk zinc-controlled feeding trial. After a 2-wk run-in period [metabolic period (MP) 1] (9.3 mg zinc/d and 2.1 g total phytate/d) to standardize zinc status, the participants consumed bread made from zinc-biofortified wheat (10.9 mg zinc/d) with no additional phytate (0.6 g/d total phytate) for 6 wk (MP2). During the final 2 wk (MP3), half of the men took a 25-mg zinc supplement daily to determine if the supplement further altered zinc status biomarkers. Repeated-measures linear regression methods were used to compare plasma zinc concentrations, fatty acid desaturase (FADS) activities, glutathione (GSH) concentrations, and DNA strand breaks assessed at enrollment and the end of each metabolic period., Results: Plasma zinc concentrations did not change throughout the study. From the end of MP1 to the end of MP2, the conversion of linoleic acid to γ-linolenic acid (FADS2 activity) increased from 0.020 to 0.025 (P = 0.02), and the conversion of dihomo-γ-linolenic acid to arachidonic acid (FADS1 activity) decreased from 6.37 to 5.53 (P = 0.01). GSH concentrations and DNA strand breaks did not change. Zinc supplementation (25 mg/d) in MP3 did not alter any of the endpoints., Conclusions: In healthy adult men, a 1.6-mg/d increase in dietary zinc from biofortified wheat modified FADS2 and FADS1 activities without changing DNA damage, plasma zinc, or GSH concentrations, demonstrating that FADS activities are more sensitive to small changes in zinc consumed with a meal. This trial was registered at clinicaltrials.gov as NCT03451214., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

This work presents new findings on the nutritional quality of recently introduced biofortified and non-biofortified cowpea cultivars as well as some common beans. ICP-MS was used for the measurements. Biofortified cowpea cultivars showed high levels of Fe and Zn, greater than 60 and 40 mg kg -1 dry weight, respectively. The in vitro digestion protocol enabled simultaneous evaluation of bioaccessibility and bioavailability. Fe levels in cowpea cultivars were ca. 2.5-fold higher than in common beans. Cowpea seeds also had higher Zn levels, reaching 50.1% bioaccessibility and 44.2% bioavailability. Cooking improved the availability of micronutrients in bean seeds. The cooked biofortified Aracê cowpea showed a high Zn bioavailability above 60%. Consumption of 50 g of Aracê would contribute 27% and 48% of the Fe and Zn DRI for 1-3-year-old children. The new cowpea cultivars biofortified are a potential vehicle for improving the Fe and Zn status in groups in which the micronutrient deficiency is prevalent., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

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.

The future of food and sustainability of the staple food crops are of utmost importance in the 21st century. Micronutrient deficiency, for example, in iron and zinc, is a common cause of human diseases. Mineral content of the staple food crops has therefore crosscutting importance for food engineering and planetary health. Finger millet, a staple food of agricultural importance worldwide, is rich in iron and zinc, and an ideal model to study the prospects of biofortified foods in times of climate change. We report here a multiomics study of the iron and zinc homeostasis in the finger millet. We identified and characterized 15 candidate genes potentially involved in iron and zinc homeostasis pathways in the finger millet. Structural and functional annotation of the candidate genes revealed a high similarity index with their respective homologs ( Oryza sativa , Triticum aestivum , Zea mays , Hordeum vulgare , and Setaria italica ). Transcriptome-wide expression analysis showed that genes involved in uptake and translocation of iron and zinc are highly expressed in the GP-1 genotype, while those involved in bioavailability of iron and zinc are expressed more in the GP-45 genotype of the finger millet. In conclusion, finger millet, being a stress-resilient crop, utilizes a combination of strategies in iron and zinc homeostasis pathway, which appear to play an important role in food crop acquisition of iron and zinc, despite environmentally limiting conditions. These data offer molecular insights on iron and zinc accumulation and paves the way for new strategies toward staple food crop with mineral biofortification.

Zinc deficiency is a major public health problem in vulnerable populations of Latin America and the Caribbean. Biofortification of rice (Oryza sativa L.) with zinc has the potential to alleviate zinc deficiencies. However, as plant breeding processes can alter grain culinary quality and favorable sensory attributes, grain quality and consumer acceptability need to be assessed prior to releasing a variety to the public. A grain quality characterization and a sensory acceptability analysis were carried out with two varieties of zinc biofortified rice and a local control both in Bolivia and Colombia. The aim of this study was to evaluate the physicochemical parameters that are significant in consumer acceptance and to determine the acceptability of zinc biofortified rice by consumers. Results of physicochemical parameters were analyzed using ANOVA. The sensory acceptability was evaluated in 243 adults utilizing a 7-point hedonic scale and a Wilcoxon's signed rank test was used to determine the overall acceptability of the varieties. Biofortified rice variety T2-11 and MAC-18 -control 1- were equally accepted by consumers in Bolivia with no significant differences (p<0.05). The grain quality analysis reported that both presented long and slender rice grains (L>7.5 mm and L/B>3), an intermediate to high amylose content (>25%) and a similar level of chalkiness. In Colombia, the biofortified variety 035 presented a higher score in overall acceptance in comparison to biofortified variety 021 and the local variety CICA4 -control 2-. However, no significant differences were observed (p<0.05). Conversely to the other two varieties, the biofortified variety 035 presented the largest size grain (L/B = 2.97), a lower chalkiness and an amylose content above 25%. This study shows that the grain quality properties of rice have an influence on acceptability and that zinc biofortified rice varieties are accepted by consumers., Competing Interests: The authors have declared that no competing interests exist.

Breeding and engineering of biofortified crops will benefit from a better understanding of bottlenecks controlling micronutrient loading within the seeds. However, few studies have addressed the changes in micronutrient concentrations, localization, and speciation occurring over time. Therefore, we studied spatial patterns of zinc and iron accumulation during grain development in two barley lines with contrasting grain zinc concentrations. Microparticle-induced-X-ray emission and laser ablation-inductively coupled plasma mass spectrometry were used to determine tissue-specific accumulation of zinc, iron, phosphorus, and sulfur. Differences in zinc accumulation between the lines were most evident in the endosperm and aleurone. A gradual decrease in zinc concentrations from the aleurone to the underlying endosperm was observed, while iron and phosphorus concentrations decreased sharply. Iron co-localized with phosphorus in the aleurone, whereas zinc co-localized with sulfur in the sub-aleurone. We hypothesize that differences in grain zinc are largely explained by the endosperm storage capacity. Engineering attempts should be targeted accordingly.

Rice is critical for sustainable food and nutritional security; however, nominal micronutrient quantities in grains aggravate malnutrition in rice-eating poor populations. In this study, we evaluated genetic diversity in grain iron (Fe) and zinc (Zn) contents using trait-linked simple sequence repeat (SSR) markers in the representative subset of a large collection of local and exotic rice germplasm. Results demonstrated that aromatic fine grain accessions contained relatively higher Fe and Zn contents in brown rice (BR) than coarse grain accessions and a strong positive correlation between both mineral elements. Genotyping with 24 trait-linked SSR markers identified 21 polymorphic markers, among which 17 demonstrated higher gene diversity and polymorphism information content (PIC) values, strongly indicating that markers used in current research were moderate to highly informative for evaluating the genetic diversity. Population structure, principal coordinate and phylogenetic analyses classified studied rice accessions into two fine grain specific and one fine and coarse grain admixture subpopulations. Single marker analysis recognized four ZnBR and single FeBR significant marker-trait associations (MTAs) contributing 15.41-39.72% in total observed phenotypic variance. Furthermore, high grain Fe and Zn contents linked marker alleles from significant MTAs were also identified. Collectively, these results indicate a wide genetic diversity exist in grain Fe and Zn contents of studied rice accessions and reveal perspective for marker-assisted biofortification breeding., Competing Interests: The authors have declared that no competing interests exist.

In the present study, transcriptomic analysis of 10-days old baby kernels of two contrasting maize genotypes, namely VQL-2 (high kernel Zn accumulator) and CM-145 (low kernel Zn accumulator), under low- and optimum- soil Zn conditions generated 1948 differentially expressed transcripts. Among these, 666 and 437 transcripts were up-regulated and down-regulated respectively in VQL-2; whereas, 437 and 408 transcripts were up-regulated and down-regulated respectively in CM-145. Remarkably, 135 transcription factors and 77 known Zn transporters expressed differentially. By comparing the transcripts differentially expressed between the optimum-Zn and low-Zn libraries of the contrasting genotypes, we identified 21,986 and 26,871 SNPs, respectively. Similarly, 6810 and 8192 InDels were found between optimum- and low-Zn growing conditions, respectively. Further, 21 differentially expressed genes were co-localized with already known QTLs associated with Zn uptake, such as qZn10, CQZnK9-1 and YNZnK6. These findings will be useful to develop high Zn-accumulator maize through marker-assisted breeding in future., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2020. Published by Elsevier Inc.)

Background: Intake of food low in essential minerals, like zinc (Zn), is one of the major reasons of malnutrition. Development of genotypes with grains enriched in essential minerals may help to solve the issue of malnutrition. In this study, 16 chickpea genotypes (eight each of desi and kabuli types) of Pakistani origin were evaluated for genetic diversity and grain Zn biofortification potential with and without Zn fertilization., Results: A wide variation was noted for agronomic, physiological, agro-physiological, utilization, and apparent recovery efficiencies of Zn in the chickpea genotypes tested. Genotypes also differed for grain Zn concentration (37.5-48.6 mg kg -1 ), bioavailable Zn (3.72-4.42 mg day -1 ), and grain yield. The highest grain Zn concentration and bioavailable Zn were noted in genotypes NIAB-CH-2016 (47.1 mg kg -1 and 4.30 mg day -1 respectively) and Noor-2013 (48.6 mg kg -1 and 4.38 mg day -1 respectively) among the desi and kabuli types respectively. The same genotypes were the highest yielders. Cluster analysis showed that all (eight) kabuli genotypes grouped together, whereas most (six) of the desi genotypes clustered in a separate group. There was low to moderate genetic diversity (0.149 for desi and 0.104 for kabuli types) and a low level of genetic differentiation between the two chickpea types (0.098)., Conclusion: Two populations of chickpea had low to moderate genetic diversity, with consistent gene flow. This genetic diversity in both chickpea types allows the breeding gains for improving the grain yield and grain Zn biofortification potential of chickpea genotypes. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Background: Nutrient deficiency in humans, especially in children and lactating women, is a major concern. Increasing the micronutrient concentration in staple crops like rice is one way to overcome this. The micronutrient content in rice, especially the iron (Fe) and zinc (Zn) content, is highly variable. The identification of rice genotypes in which there are naturally high Fe and Zn concentrations across environments is an important target towards the production of biofortified rice., Results: Phenotypic correlations between grain Fe and Zn content were positive and significant in all environments but a significant negative association was observed between grain yield and grain Fe and Zn. Promising breeding lines with higher Zn or Fe content, or both, were: IR 82475-110-2-2-1-2 (Zn: 20.24-37.33 mg kg -1 ; Fe: 7.47-14.65 mg kg -1 ); IR 83294-66-2-2-3-2 (Zn: 22-37-41.97 mg kg -1 ; Fe: 9.43-17.16); IR 83668-35-2-2-2 (Zn: 27.15-42.73 mg kg -1 ; Fe: 6.01-14.71); IR 68144-2B-2-2-3-1-166 (Zn: 23.53-40.30 mg kg -1 ; Fe: 10.53-17.80 mg kg -1 ) and RP Bio 5478-185M7 (Zn: 22.60-40.07 mg kg -1 ; Fe: 7.64-14.73 mg kg -1 ). Among these, IR82475-110-2-2-1-2 (Zn: 20.24-37.33 mg kg -1 ; Fe: 7.47-14.65 mg kg -1 ) is also high yielding with 3.75 t ha -1 . Kelhrie Cha (Zn: 17.76-36.45 mg kg -1 ; Fe: 7.17-14.77 mg kg -1 ), Dzuluorhe (Zn: 17.48-39.68 mg kg -1 ; Fe: 7.89-19.90 mg kg -1 ), Nedu (Zn: 18.97-43.55 mg kg -1 Fe: 8.01-19.51 mg kg -1 ), Kuhusoi-Ri-Sareku (Zn: 17.37-44.14 mg kg -1 ; Fe: 8.99-14.30 mg kg -1 ) and Mima (Zn: 17.10-45.64 mg kg -1 ; Fe: 9.97-17.40 mg kg -1 ) were traditional donor genotypes that possessed both high grain Fe and high Zn content., Conclusion: Significant genotype × location (G × L) effects were observed in all traits except Fe. Genetic variance was significant and was considerably larger than the variance of G × L for grain Zn and Fe content traits, except grain yield. The G × L × year variance component was significant in all cases. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Grain yield and mineral nutrient concentration in cereal crops are usually inversely correlated, undermining biofortification efforts. Here, sink size, expressed as kernel number per cob, was manipulated by controlling the time when the silks of sweetcorn (Zea mays) cv. Hybrix 5 and var. HiZeax 103146 were exposed to pollen. Twelve other varieties were manually pollinated to achieve the maximum potential kernel number per cob, and kernel Zn concentration was correlated with kernel number and kernel mass. As kernel number increased, kernel Zn concentration decreased, with the decrease occurring to similar extents in the embryo tissue and the rest of the kernel. However, total kernel Zn accumulated per cob increased with increasing kernel number, as the small decreases in individual kernel Zn concentration were more than offset by increases in kernel number. When both kernel number and mass were considered, 90% of the variation in kernel Zn concentration was accounted for. Differential distribution of assimilates and Zn to sweetcorn cobs led to significant decreases in kernel Zn concentration with increasing kernel number. This suggests there will be challenges to achieving high kernel Zn concentrations in modern high-yielding sweetcorn varieties unless genotypes with higher Zn translocation rates into kernels can be identified., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

Human zinc (Zn) deficiency is prevalent in areas where cereals dominate in the diet. Soil Zn application may enhance the concentration of Zn in wheat grains and dietary Zn intake by target populations. However, its value has never been practically quantified in Zn nutrition of any population group. We, therefore, studied farming families in rural Punjab (Pakistan). The selected adults (n = 156, grouped based on age and gender) were Zn undernourished (as assessed by estimated Zn bioavailability in their diet) and their plasma Zn levels also indicated Zn deficiency. On average, wheat consumption by the adults contributed about 68% in total Zn and 93% in total phytate intakes. Soil Zn application to wheat fields significantly increased Zn and decreased phytate concentration in chapati (flatbread made of whole-wheat flour). From dietary phytate intakes by the adults, we calculated desired chapati Zn concentration and dietary Zn intake that would meet their daily Zn requirement. The physiological Zn requirements of adult women and men were estimated to be achieved by intake of, respectively, 10.4-15.3 mg Zn d -1 (37-46 mg Zn kg -1 in chapati) and 14.4-23.3 mg Zn d -1 (41-52 mg Zn kg -1 in chapati). It was evident that soil Zn application aiming at optimum grain yield of wheat significantly improved Zn nutrition of the studied adults, but not up to desired levels. High Zn applications (via soil and/or foliage) to wheat and growing cultivars specifically selected for Zn biofortification may be needed to optimise Zn nutrition in rural Pakistan.

Wheat (T. aestivum L.) is the second most important staple food crop consumed in the form of various end-use products across the world. However, it contains lower concentrations of Fe and Zn leading to micronutrient deficiency in human beings where wheat is the sole diet. Therefore, increasing grain Fe/Zn content in wheat has become priority in wheat breeding programmes across the world. Understanding the molecular mechanism of Fe/Zn transport and accumulation in grains is required to expedite the breeding process. For this purpose, whole seedling transcriptome analysis was conducted in four wheat genotypes (CRP 1660, Sonora 64, Vinata, : high, and DBW17: low) differing in grain Fe/Zn content under controlled and Fe/Zn deficient conditions. Twenty eight key transcripts involved in phytosiderophore biosynthesis, Fe/Zn uptake and transport were identified. Expression analysis of 12 of the transcripts using qPCR was conducted in seedling stage and flag leaf which exhibited greater differential accumulation in CRP 1660 followed by Vinata, Sonora 64 and DBW 17 in both flag leaf and seedling. However, there was significantly higher differential accumulation of the transcripts in flag leaf as compared to seedling. In CRP 1660, transcripts pertaining to phytosiderophore biosynthesis like DMAS1-B, NRAMP2 and NAAT2-D showed greater accumulation. Additionally, corresponding miRNAs were also identified for these 28 transcripts. The findings will help in better understanding of molecular basis of Fe/Zn transport and accumulation in grain and subsequent utilization in breeding to improve Fe/Zn content in wheat grain., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Biofortification is an effective method to improve the nutritional content of crops and nutritional intake. Breeding for higher micronutrient mineral content in beans is correlated with an increase in phytic acid, a main inhibitor of mineral absorption in humans. Low phytic acid ( lpa ) beans have a 90% lower phytic acid content compared to conventional beans. This is the first study to investigate mineral and total phytic acid retention after preparing common household recipes from conventional, biofortified and lpa beans. Mineral retention was determined for two conventional, three biofortified and two lpa bean genotypes. Treatments included soaking, boiling (boiled beans) and refrying (bean paste). The average true retention of iron after boiling was 77.2-91.3%; for zinc 41.2-84.0%; and for phytic acid 49.9-85.9%. Soaking led to a significant decrease in zinc and total phytic acid after boiling and refrying, whereas for iron no significant differences were found. lpa beans did not exhibit a consistent pattern of difference in iron and phytic acid retention compared to the other groups of beans. However, lpa beans had a significantly lower retention of zinc compared to conventional and biofortified varieties ( p < 0.05). More research is needed to understand the underlying factors responsible for the differences in retention between the groups of beans, especially the low retention of zinc. Combining the lpa and biofortification traits could further improve the nutritional benefits of biofortified beans, by decreasing the phytic acid:iron and zinc ratio in beans., Competing Interests: The authors declare no conflict of interest.

Pleurotus eryngii (DC:Fr.) Quel. is a cultivated mushroom of high culinary value and medicinal properties. Mycelium of P. eryngii is characterized by the ability of effective bio-elements absorption from growth media so it could be biofortified with trace elements with a functional activity in the human body. In this study, the ability of P. eryngii mycelia from in vitro cultures as well as fruiting bodies were investigated in terms of their effectiveness in zinc and selenium accumulation. The effect of Se and Zn biofortification on productivity, chemical compounds, and bio-elements content of P. eryngii was determined as well. To enhance Se and Zn content in P. eryngii fruiting bodies and mycelia, substrates were supplemented with sodium selenite, at a concentration of 50 mg L -1 , zinc sulfate, and zinc hydro-aspartate at a concentration of 87.2 and 100.0 mg L -1 , respectively. Mentioned Zn concentrations contained the same amount of zinc(II) ions, namely 20 mg L -1 . The content of organic compounds include phenolic compounds and lovastatin, which were determined by a high-performance liquid chromatography with diode-array detector (HPLC-DAD) and reverse phase high-performance liquid chromatography (RP-HPLC) method with UV detection. The ability of P. eryngii to accumulate zinc and selenium from the culture medium was demonstrated. The degree of accumulation of zinc turned out to be different depending on the type of salt used. The present study also showed that conducting mycelium of P. eryngii in in vitro culture, with a higher content of zinc ions, can result in obtaining the materials with better antioxidant ability. The results of this study can be used to develop the composition of growing media, which ensures the production of biomass with the desired composition of elements.

Enrichment of food crops with iodine is an option to alleviate dietary deficiencies. Therefore, foliar iodine fertilizer was applied on wheat and rice, in the presence and absence of the other micronutrients zinc and selenium. This treatment increased the concentration of iodine, as well as zinc and selenium, in the staple grains. Subsequently, potential iodine losses during preparation of foodstuffs with the enriched grains were studied. Oven-heating did not affect the iodine content in bread. Extraction of bran from flour lowered the iodine in white bread compared to wholegrain bread, but it was still markedly higher compared to the control. During subsequent in vitro gastrointestinal digestion, a higher percentage of iodine was released from foods based on extracted flour (82-92%) compared to wholegrain foods (50-76%). The foliar fertilization of wheat was found to be adequate to alleviate iodine deficiency in a population with a moderate to high intake of bread.

Background: High yielding rice varieties are usually low in grain iron (Fe) and zinc (Zn) content. These two micronutrients are involved in many enzymatic activities, lack of which cause many disorders in human body. Bio-fortification is a cheaper and easier way to improve the content of these nutrients in rice grain., Results: A population panel was prepared representing all the phenotypic classes for grain Fe-Zn content from 485 germplasm lines. The panel was studied for genetic diversity, population structure and association mapping of grain Fe-Zn content in the milled rice. The population showed linkage disequilibrium showing deviation of Hardy-Weinberg's expectation for Fe-Zn content in rice. Population structure at K = 3 categorized the panel population into distinct sub-populations corroborating with their grain Fe-Zn content. STRUCTURE analysis revealed a common primary ancestor for each sub-population. Novel quantitative trait loci (QTLs) namely qFe3.3 and qFe7.3 for grain Fe and qZn2.2, qZn8.3 and qZn12.3 for Zn content were detected using association mapping. Four QTLs, namely qFe3.3, qFe7.3, qFe8.1 and qFe12.2 for grain Fe content were detected to be co-localized with qZn3.1, qZn7, qZn8.3 and qZn12.3 QTLs controlling grain Zn content, respectively. Additionally, some Fe-Zn controlling QTLs were co-localized with the yield component QTLs, qTBGW, OsSPL14 and qPN. The QTLs qFe1.1, qFe3.1, qFe5.1, qFe7.1, qFe8.1, qZn6, qZn7 and gRMm9-1 for grain Fe-Zn content reported in earlier studies were validated in this study., Conclusion: Novel QTLs, qFe3.3 and qFe7.3 for grain Fe and qZn2.2, qZn8.3 and qZn12.3 for Zn content were detected for these two traits. Four Fe-Zn controlling QTLs and few yield component QTLs were detected to be co-localized. The QTLs, qFe1.1, qFe3.1, qFe5.1, qFe7.1, qFe8.1, qFe3.3, qFe7.3, qZn6, qZn7, qZn2.2, qZn8.3 and qZn12.3 will be useful for biofortification of the micronutrients. Simultaneous enhancement of Fe-Zn content may be possible with yield component traits 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.

Nowadays, Zinc (Zn) deficiency is the most widespread micronutrient deficiency but simultaneously Zn toxicity is produced due to environmental pollution. A potential method to alleviate Zn deficiency and to reduce Zn concentration in soils is through the generation of plants with enhanced capacity for Zn accumulation and higher tolerance. This could be achieved through the modification of HMA4 transporter. BraA.hma4a-3 is a TILLING mutant plant that presents one modification in HMA4 transporter. Thus, in this study we analyzed the potential of BraA.hma4a-3 for Zn accumulation and Zn deficiency and toxicity tolerance. BraA.hma4a-3 and parental R-o-18 plants were grown with different Zn doses: 1 μM ZnSO 4 (Control), 0.01 μM ZnSO 4 (Zn deficiency) and 100 μM ZnSO 4 (Zn toxicity). Parameters of biomass, Zn concentration, photosynthesis, oxidative stress, N metabolism and amino acids (AAs) were measured. BraA.hma4a-3 did not affect plant biomass but did increase Zn accumulation in leaves under an adequate Zn supply and Fe under control and Zn deficiency doses. Regarding stress tolerance parameters and N metabolism, BraA.hma4a did not produce alterations under control conditions. In addition, under Zn toxicity, parameters suggest a greater tolerance. Briefly, the obtained results point to BraA.hma4a-3 as a useful mutant to increase Zn accumulation., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Cu, Fe, Mn, Mo, Selenium (Se), and Zn bioavailability from selenate- and selenite-enriched lettuce plants was studied by in vitro gastrointestinal digestion followed by an assay with Caco-2 cells. The plants were cultivated in the absence and presence of two concentrations (25 and 40 µmol/L of Se). After 28 days of cultivation, the plants were harvested, dried, and evaluated regarding the total concentration, bioaccessibility, and bioavailability of the analytes. The results showed that biofortification with selenate leads to higher Se absorption by the plant than biofortification with selenite. For the other nutrients, Mo showed high accumulation in the plants of selenate assays, and the presence of any Se species led to a reduction of the plant uptake of Cu and Fe. The accumulation of Zn and Mn was not strongly influenced by the presence of any Se species. The bioaccessibility values were approximately 71%, 10%, 52%, 84%, 71%, and 86% for Cu, Fe, Mn, Mo, Se, and Zn, respectively, and the contribution of the biofortified lettuce to the ingestion of these minerals is very small (except for Se and Mo). Due to the low concentrations of elements from digested plants, it was not possible to estimate the bioavailability for some elements, and for Mo and Zn, the values are below 6.9% and 3.4% of the total concentration, respectively. For Se, the bioavailability was greater for selenite-enriched than selenate-enriched plants (22% and 6.0%, respectively), because selenite is biotransformed by the plant to organic forms that are better assimilated by the cells., (© 2019 Institute of Food Technologists®.)

There is a growing recognition of the role of arbuscular mycorrhizal fungi (AMF) in food security, specifically the potential for AMF to enhance the yield and mineral nutrition-including phosphorus, zinc (Zn), and iron (Fe)-of food crops. However, the bioavailability of Zn and Fe for humans in the grain of cereal crops can be overestimated by failing to consider the abundance of phytic acid (PA). This is because PA can chelate the micronutrients, making them difficult to absorb. In order to understand the effect of an AM fungus and soil Zn concentration on the productivity and nutritional quality of food parts, this study examined the growth and nutritional responses of durum wheat, with and without inoculation with Rhizophagus irregularis, at five soil Zn concentrations. Growth and nutrient responses of the plants to soil Zn amendment was stronger than responses to AMF. However, the protective effect of AMF under soil Zn toxicity conditions was observed as reduced Zn concentration in the mycorrhizal durum wheat grain at Zn50. Here, AMF inoculation increased the concentration of PA in durum wheat grain but had no effect on the concentration of Zn and Fe; this consequently reduced the predicted bioavailability of grain Zn and Fe, which could lead to a decrease in nutritional quality of the grain. This research suggests that in soil with low (available) phosphorus and Zn concentrations, AMF may reduce the food quality of durum wheat because of an increase in PA concentration, and thus, a decrease in the bioavailability of Zn and Fe.

Background: Hexaploid wheat is an important cereal crop that has been targeted to enhance grain micronutrient content including zinc (Zn) and iron (Fe). In this direction, modulating the expression of plant transporters involved in Fe and Zn homeostasis has proven to be one of the promising approaches. The present work was undertaken to identify wheat zinc-induced facilitator-like (ZIFL) family of transporters. The wheat ZIFL genes were characterized for their transcriptional expression response during micronutrient fluctuations and exposure to multiple heavy metals., Results: The genome-wide analyses resulted in identification of fifteen putative TaZIFL-like genes, which were distributed only on Chromosome 3, 4 and 5. Wheat ZIFL proteins subjected to the phylogenetic analysis showed the uniform distribution along with rice, Arabidopsis and maize. In-silico analysis of the promoters of the wheat ZIFL genes demonstrated the presence of multiple metal binding sites including those which are involved in Fe and heavy metal homeostasis. Quantitative real-time PCR analysis of wheat ZIFL genes suggested the differential regulation of the transcripts in both roots and shoots under Zn surplus and also during Fe deficiency. Specifically, in roots, TaZIFL2.3, TaZIFL4.1, TaZIFL4.2, TaZIFL5, TaZIFL6.1 and TaZIFL6.2 were significantly up-regulated by both Zn and Fe. This suggested that ZIFL could possibly be regulated by both the nutrient stress in a tissue specific manner. When exposed to heavy metals, TaZIFL4.2 and TaZIFL7.1 show significant up-regulation, whereas TaZIFL5 and TaZIFL6.2 remained almost unaffected., Conclusion: This is the first report for detailed analysis of wheat ZIFL genes. ZIFL genes also encode for transporter of mugineic acid (TOM) proteins, that are involved in the release of phytosiderophores to enhance Fe/Zn uptake. The detailed expression analysis suggests the varying expression patterns during development of wheat seedlings and also against abiotic/biotic stresses. Overall, this study will lay foundation to prioritize functional assessment of the candidate ZIFL as a putative TOM protein in wheat.

Heavy metal contaminants and nutrient deficiencies in soil negatively affect crop growth and human health. The plant cadmium resistance (PCR) protein transports heavy metals. The abundance of PCR is correlated with that of cell number regulator (CNR) protein, and the two proteins have similar conserved domains. Hence, CNR might also participate in heavy metal transport. We isolated and analyzed TaCNR5 from wheat ( Triticum aestivum ). The expression level of TaCNR5 in the shoots of wheat increased under cadmium (Cd), zinc (Zn), or manganese (Mn) treatments. Transgenic plants expressing TaCNR5 showed enhanced tolerance to Zn and Mn. Overexpression of TaCNR5 in Arabidopsis increased Cd, Zn, and Mn translocation from roots to shoots. The concentrations of Zn and Mn in rice grains were increased in transgenic plants expressing TaCNR5 . These roles of TaCNR5 in the translocation and distribution of heavy metals mean that it has potential as a genetic biofortification tool to fortify cereal grains with micronutrients.

Zinc (Zn) and iron (Fe) are essential micronutrients for plant growth. Thus, it is important to understand the mechanisms of uptake, transport and accumulation of these micronutrients in maize to improve crop nutritional quality. Members of the zinc-regulated transporters, iron-regulated transporter-like protein (ZIP) family are responsible for the uptake and transport of divalent metal ions in plant. Previously, we showed that ZmZIP5 functionally complemented the Zn uptake double mutant zrt1zrt2, Fe-uptake double mutant fet3fet4 in yeast. In our β-glucuronidase (GUS) assay, the germinated seeds, young sheaths, and stems of ZmZIP5-promoter-GUS transgenic plants were stained. We generated and compared two maize lines for this study: Ubi-ZmZIP5, in which ZmZIP5 was constitutively overexpressed, and ZmZIP5i, a RNAi line. At the seedling stage, high levels of Zn and Fe were found in the roots and shoots of Ubi-ZmZIP5 plants, whereas low levels were found in the ZmZIP5i plants. Zn and Fe contents decreased in the seeds of Ubi-ZmZIP5 plants and remained unchanged in the seeds of ZmZIP5i plants. The seeds of Leg-ZmZIP5 plants, in which ZmZIP5 overexpression is specific to the endosperm, had higher levels of Zn and Fe. Our results imply that ZmZIP5 may play a role in Zn and Fe uptake and root-to-shoot translocation. Endosperm-specific ZmZIP5 overexpression could be useful for Zn and Fe biofortification of cereal grains., (� The Author(s) 2019. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Iron (Fe) and zinc (Zn) deficiencies are wide spread in South Asia and Africa. Biofortification of food crops is a viable means of addressing micronutrient deficiencies. Lentil is an important pulse crop that provides affordable source of proteins, minerals, fibre and carbohydrates for micronutrient deficient countries. An association mapping (AM) panel of 96 diverse lentil genotypes from India and Mediterranean region was evaluated for three seasons and genotyped using 80 polymorphic simple-sequence repeat (SSR) markers for identification of the markers associated with grain Fe and Zn concentrations. A Bayesian model based clustering identified five subpopulations, adequately explaining the genetic structure of the AM panel. The linkage disequilibrium (LD) analysis using mixed linear model (MLM) identified two SSR markers, GLLC106 and GLLC108, associated with grain Fe concentration explaining 17% and 6% phenotypic variation, respectively and three SSR markers (PBALC 364, PBALC 92 and GLLC592) associated with grain Zn concentration, explaining 6%, 8% and 13% phenotypic variation, respectively. The identified SSRs exhibited consistent performance across three seasons and have potential for utilization in lentil molecular breeding programme.

The present work evaluated the effect of different processes in relation to mineral content and its bioavailability, as well as the effect of phytate and oxalate contents in biofortified beans. The following treatments were evaluated: raw beans (RB), cooked and oven-dried soaked beans (BOS), cooked and freeze-dried soaked beans (BFS), cooked and oven-dried beans without soaking (BOWS) and cooked and freeze-dried beans without soaking (BFWS). The mineral contents (mg per 100 g) varied between 3.56 and 5.80 (iron), 20.26 and 89.32 (calcium) and 1.56 and 2.38 (zinc). The oxalate content varied from 3.74 to 10.54 mg per 100 g. The total phytate content ranged from 1803.23 to 2.301 mg per 100 g. Regarding mineral bioavailability in Caco-2 cells, iron retention ranged from 8.89 to 17.85% and uptake was from 12.07 to 13.74 μg. On the other hand, the zinc retention was from 92.27 to 98.6% and uptake ranged from 24.68 to 36.26 μg. The different forms of bean processing can contribute to the mineral profile of this legume, in addition to increasing the bioavailability of some minerals, such as iron and zinc.

Field experiments were conducted on wheat to study the effects of foliar-applied iodine(I) alone, Zn (zinc) alone, and a micronutrient cocktail solution containing I, Zn, Se (selenium), and Fe (iron) on grain yield and grain concentrations of micronutrients. Plants were grown over 2 years in China, India, Mexico, Pakistan, South Africa, and Turkey. Grain-Zn was increased from 28.6 mg kg -1 to 46.0 mg -1 kg with Zn-spray and 47.1 mg -1 kg with micronutrient cocktail spray. Foliar-applied I and micronutrient cocktail increased grain I from 24 μg kg -1 to 361 μg kg -1 and 249 μg kg -1 , respectively. Micronutrient cocktail also increased grain-Se from 90 μg kg -1 to 338 μg kg -1 in all countries. Average increase in grain-Fe by micronutrient cocktail solution was about 12%. The results obtained demonstrated that foliar application of a cocktail micronutrient solution represents an effective strategy to biofortify wheat simultaneously with Zn, I, Se and partly with Fe without yield trade-off in wheat.

Background: Intensive cropping systems have caused widespread Zn deficiency, low nutritional quality of cereals and environmental problems. The aim of the microplot field experiment reported in this paper was to assess the option of using Zn in conjunction with urea fertilization in order to reduce N rate and to maintain the yield level and grain quality but minimizing environmental risks. Barley (Hordeum vulgare L.) was cultivated in a calcareous soil under semi-realistic conditions. Combinations of four Zn levels, applied by spraying aqueous solutions of ZnSO 4 , and three N levels, applied by spreading granular urea, were tested., Results: Zn and N showed a synergistic effect, increasing yield and Zn content in all plant parts and protein content in grain. A low Zn dosage of 5 kg ha -1 was sufficient to significantly increase the amount of bioavailable Zn in soil and significantly raise its concentration in plant material and also the protein content in grain. The remobilization of Zn from leaf tissue to grain was dependent on the availability of Zn and was only crucial when its bioavailability was low., Conclusions: A Zn dosage of 5 kg ha -1 enhanced the agronomic efficiency of N by 15.5 kg grain kg -1 N. The Zn applied to the soil permitted a reduction in the rate of N with only a small decrease in barley grain yield and nutritional value. However, due to the interannual variability in rainfall, which is characteristic of Mediterranean climates, further studies will be necessary to confirm and extend these results. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Main Conclusion: In sweetcorn (Zea mays L.), embryo Zn is accumulated mainly as Zn-phytate, whereas endosperm Zn is complexed with a N- or S-containing ligand. Understanding the speciation of Zn in crop plants helps improve the effectiveness of biofortification efforts. Kernels of four sweetcorn (Zea mays L.) varieties were analysed for Zn concentration and content. We also assessed the speciation of the Zn in the embryo, endosperm, and pericarp in situ using synchrotron-based X-ray absorption spectroscopy. The majority of the Zn was in the endosperm and pericarp (72%), with the embryo contributing 28%. Approximately 79% of the Zn in the embryo accumulated as Zn-phytate, whereas in the endosperm most of the Zn was complexed with a N- or S-containing ligand, possibly as Zn-histidine and Zn-cysteine. This suggests that whilst the Zn in the endosperm and pericarp is likely to be bioavailable for humans, the Zn in the embryo is of low bioavailability. This study highlights the importance of targeting the endosperm of sweetcorn kernels as the tissue for increasing bioavailable Zn concentration.