Zinc Biofortification Research Articles

Cross Talk Between Zinc-Solubilizing Bacteria and Plants: A Short Tale of Bacterial-Assisted Zinc Biofortification

A contemporary approach to bacterially mediated zinc (Zn) biofortification offers a new dimension in the crop improvement program with better Zn uptake in plants to curb Zn malnutrition. The implication of Zn solubilizing bacteria (ZSB) represents an inexpensive and optional strategy for Zn biofortification, with an ultimate green solution to enlivening sustainable agriculture. ZSB dwelling in the rhizospheric hub or internal plant tissues shows their competence to solubilize Zn via a variety of strategies. The admirable method is the deposition of organic acids (OAs), which acidify the surrounding soil environment. The secretion of siderophores as a metal chelating molecule, chelating ligands, and the manifestation of an oxidative–reductive system on the bacterial cell membrane are further tactics of bacterially mediated Zn solubilization. The inoculation of plants with ZSB is probably a more effective tactic for enhanced Zn translocation in various comestible plant parts. ZSB with plant growth-enhancing properties can be used as bioelicitors for sustainable plant growth via the different approaches that are crucial for plant health and its productivity. This article provides an overview of the functional properties of ZSB-mediated Zn localization in the edible portions of food crops and provides an impetus to explore such plant probiotics as natural biofortification agents.

Accumulation of zinc, iron and selenium in wheat as affected by phosphorus supply in salinised condition

Biofortification of zinc (Zn), iron (Fe) and selenium (Se) in crops could be affected by environmental factors such as soil salinity and phosphorus supply levels, as well as by the genotypic effect. Two pot experiments were conducted with one examined the effects of P supply and salinity on plant growth and Zn, Fe and Se uptake in wheat, and the other examined genotypic differences in Zn, Fe and Se accumulation among 20 wheat genotypes. The results of the first pot study showed significant interactive effects between P supply and salinity on Zn, Fe and Se accumulation. Increasing salinity at the same P supply level increased shoot Zn concentrations, but significantly decreased total shoot Zn amount owing to decreased aboveground biomass. An increased accumulation of total shoot Fe and Se in P-added treatments, relative to the no-P treatments, was mainly due to increased aboveground biomass. The results of the second pot study showed substantial genotypic variations in Zn, Fe and Se accumulation; principal component analysis (PCA) suggested that agronomic traits and nutrient accumulation were controlled by independent genetic mechanisms. These results indicated that the amount of P supply is a key factor regulating biomass and accumulation of Zn, Fe and Se in certain saline soils; the sizable genotypic difference in Zn, Fe and Se accumulation observed in salinised conditions has provided potential scope for genetic improvement by breeding strategies.

Quantitative Trait Loci and Candidate Genes for Iron and Zinc Bio-Fortification in Genetically Diverse Germplasm of Maize (Zea Mays L): A Review

Quantitative Trait Loci and Candidate Genes for Iron and Zinc Bio-Fortification in Genetically Diverse Germplasm of Maize (Zea Mays L): A Review

Improvement of Processing Quality and Yield while Sustaining Consumer Acceptability of Cobb Broiler Meat through Zinc Biofortification

Improvement of Processing Quality and Yield while Sustaining Consumer Acceptability of Cobb Broiler Meat through Zinc Biofortification

Effect of zinc biofortification on yield, nutrient uptake and economics of pearl millet

Effect of zinc biofortification on yield, nutrient uptake and economics of pearl millet

Multi-year field evaluation of nicotianamine biofortified bread wheat.

Conventional breeding efforts for iron (Fe) and zinc (Zn) biofortification of bread wheat (Triticum aestivum L.) have been hindered by a lack of genetic variation for these traits and a negative correlation between grain Fe and Zn concentrations and yield. We have employed genetic engineering to constitutively express (CE) the rice (Oryza sativa) nicotianamine synthase 2 (OsNAS2) gene and upregulate biosynthesis of two metal chelators - nicotianamine (NA) and 2'-deoxymugineic acid (DMA) - in bread wheat, resulting in increased Fe and Zn concentrations in wholemeal and white flour. Here we describe multi-location confined field trial (CFT) evaluation of a low-copy transgenic CE-OsNAS2 wheat event (CE-1) over 3 years and demonstrate higher concentrations of NA, DMA, Fe, and Zn in CE-1 wholemeal flour, white flour, and white bread and higher Fe bioavailability in CE-1 white flour relative to a null segregant (NS) control. Multi-environment models of agronomic and grain nutrition traits revealed a negative correlation between grain yield and grain Fe, Zn, and total protein concentrations, yet no correlation between grain yield and grain NA and DMA concentrations. White flour Fe bioavailability was positively correlated with white flour NA concentration, suggesting that NA-chelated Fe should be targeted in wheat Fe biofortification efforts.

Zinc-Coated Urea for Enhanced Zinc Biofortification, Nitrogen Use Efficiency and Yield of Basmati Rice under Typic Fluvents

Deficiency of Zn in human diet is an emerging health issue in many developing countries across the globe. Agronomic Zn biofortification using diverse Zn fertilization options is being advised for enhancing Zn concentration in the edible portion of rice.A field study was carried out to find out the Zn fertilization effects on biofortification of basmati rice and nutrient use efficiencies in the Himalayan foothills region. Amongst the Zn nutrition treatments, 4.0% Zn-coated urea (ZnCU) + 0.2% Zn foliar spray (FS) using ZnSO4·7H2O recorded the highest grain (3.46 t/ha) and straw (7.93 t/ha) yield of basmati rice. On average, the rice productivity increase due to ZnCU application was ~25.4% over Commercial Urea. Likewise, the same Zn fertilization treatment also resulted in the maximum Zn (35.93 and 81.64 mg/kg) and N (1.19 and 0.45%) concentration in grain and straw of rice, respectively. Moreover, N use efficiency (NUE) was also highest when ZnCU was applied at 4.0% (ZnSO4·7H2O) in comparison to soil application. From the grain quality viewpoint, Zn ferti-fortification had significant effect on elongation ratio and protein concentration of grain only and respective Zn fertilization treatment recorded highest quality parameters 1.90 and 7.44%, respectively. Therefore, ZnCU would be an important low-cost and useful strategy for enhancing yield, NUE and biofortification, and also in minimizing the Zn malnutrition related challenges in human diet in many developing economies.

Spraying high concentrations of chelated zinc enhances zinc biofortification in wheat grain.

Foliar application of highly concentrated ZnSO4 fertilizer improves Zn biofortification in wheat grains. However, excess ZnSO4 ·7H2 O concentration (≥5g kg-1 , w v-1 ) has been associated with leaf burn and yield loss, necessitating Zn sources with a high threshold concentration. The aim of this study, based on a 2 year field experiment conducted on wheat cultivated in acidic and alkaline soil, was to identify a suitable Zn formulation with a high Zn concentration or efficient adjuvant to achieve optimal Zn biofortification levels without compromising agronomic performance. There was a continued increase in the Zn concentration in wheat grains and a decrease in grain yield with an increase in the concentration of the Zn foliar sprays in both soil types examined. Wheats treated with chelated Zn foliar sprays - Zn glycine chelate (ZnGly) and Zn-ethylenediaminetetraacetic acid (ZnEDTA) - had less foliar injury than those treated with unchelated Zn fertilizers. Furthermore, irrespective of wheat cultivars and soil types, ZnEDTA applied to wheat at a concentration of 10g kg-1 achieved the highest grain Zn concentration without negatively affecting the wheat performance. Adjuvant type and concentration caused no significant variation in grain Zn concentration. Overall, without foliar burn, wheat treated with 10g kg-1 ZnEDTA foliar spray had the best performance with regard to grain Zn concentration and grain yield, which could have considerable implications for Zn biofortification of wheat grain. © 2021 Society of Chemical Industry.

Genetic Approaches for Iron and Zinc Biofortification and Arsenic Decrease in Oryza sativa L. Grains.

Rice is the staple diet to half of the world's population, being a major source of carbohydrates, vitamins, and some essential elements. However, rice naturally contains low amounts of essential minerals such as iron (Fe) and zinc (Zn), which are drastically decreased after milling. Thus, populations that consume mostly rice may have micronutrient deficiency, which is associated with different diseases. On the other hand, rice irrigated by flooding has a high ability to accumulate arsenic (As) in the grain. Therefore, when rice is grown in areas with contaminated soil or irrigation water, it represents a risk factor for consumers, since As is associated with cancer and other diseases. Different strategies have been used to mitigate micronutrient deficiencies such as Fe and Zn and to prevent As from entering the food chain. Each strategy has its positive and its negative sides. The development of genetically biofortified rice plants with Fe and Zn and with low As accumulation is one of the most promising strategies, since it does not represent an additional cost for farmers, and gives benefits to consumers as well. Considering the importance of genetic improvement (traditional or molecular) to decrease the impact of micronutrient deficiencies such as Fe and Zn and contamination with As, this review aimed to summarize the major efforts, advances, and challenges for genetic biofortification of Fe and Zn and decrease in As content in rice grains.

Mineral composition, chlorophyll fluorescence and zinc biofortification in Vigna unguiculata fertilized with bulk and nanoparticulate zinc oxides

Mineral composition, chlorophyll fluorescence and zinc biofortification in Vigna unguiculata fertilized with bulk and nanoparticulate zinc oxides

Next-generation technologies for iron and zinc biofortification and bioavailability in cereal grains

Iron (Fe) and zinc (Zn) are recognised as micronutrients of clinical significance to public health globally. Major staple crops (wheat, rice and maize) contain insufficient levels of these micronutrients. Baseline concentrations in wheat and maize grains are 30 µg/g for Fe and 25 µg/g for Zn, and in rice grains, 2 µg/g for Fe and 16 µg/g for Zn. However, wheat grains should contain 59 μg Fe/g and 38 μg Zn/g if they are to meet 30–40% of the average requirement of an adult diet. Scientists are addressing malnutrition problems by trying to enhance Fe and Zn accumulation in grains through conventional and next-generation techniques. This article explores the applicability and efficiency of novel genome editing tools compared with conventional breeding for Fe and Zn biofortification and for improving the bioavailability of cereal grains. Some wheat varieties with large increases in Zn concentration have been developed through conventional breeding (e.g. BHU1, BHU-6 and Zincol-2016, with 35–42 µg Zn/g); however, there has been little such success with Fe concentration. Similarly, no rice variety has been developed through conventional breeding with the required grain Fe concentration of 14.5 µg/g. Transgenic approaches have played a significant role for Fe and Zn improvement in cereal crops but have the limitations of low acceptance and strict regulatory processes. Precise editing by CRISPR-Cas9 will help to enhance the Fe and Zn content in cereals without any linkage drag and biosafety issues. We conclude that there is an urgent need to biofortify cereal crops with Fe and Zn by using efficient next-generation approaches such as CRISPR/Cas9 so that the malnutrition problem, especially in developing countries, can be addressed.

Agronomic bio-fortification of iron, zinc and selenium enhance growth, quality and uptake of different sorghum accessions

Agronomic bio-fortification is one of the main approaches for mitigation of micronutrient shortage in human populations and endorses sustainable production of food and feed. Studies related to agronomic bio-fortification of crops are mainly focused on single or rarely two micronutrients application, and no attempt has made to study the combined effect of zinc (Zn), iron (Fe) and selenium (Se) on forage sorghum. Therefore, this research was accomplished to evaluate the effect of Zn, Fe and Se bio-fortification on diverse sorghum accessions. The field experiments were conducted in a randomised complete block design with a split-plot arrangement. The treatments comprised of Zn (10 mg/L as ZnSO<sub>4</sub>∙5H<sub>2</sub>O), Fe (7 mg/L as FeSO<sub>4</sub>∙7H<sub>2</sub>O), Se (3 mg/L as SeSO<sub>4</sub>) and CK (control) were applied to five sorghum accessions: G<sub>1</sub> (Y-16), G<sub>2</sub> (YSH-166), G<sub>3</sub> (YSH-134), G<sub>4</sub> (YSS-98) and G<sub>5</sub> (YSH-132). According to our results, the sorghum accession G<sub>5</sub> showed superiority over all other accessions and produced maximum values of all growth and quality traits except grains number per panicle and 1 000-grain weight. All applied micronutrients (Zn, Fe and Se) enhanced the growth, quality and uptake of nutrients in sorghum accessions. However, Se recorded the highest plant height, stem diameter, 1 000-grain weight and Zn produced the maximum protein, oil and starch contents. Conclusively, it can be concluded that G<sub>5</sub> with Se must be used to achieve the optimum values of agronomic traits, while G<sub>5</sub> with Zn found more effective to improve the quality traits of sorghum.

Relationship of grain micronutrient concentrations and grain yield components in a doubled haploid bread wheat (

Bread wheat (Triticum aestivum L.) is an important cereal crop that provides >20% of the global calorie intake. Bread wheat contains micronutrients, and thus plays a significant role in nutritional and food securities especially in developing countries. However, its grains are inherently deficient in some micronutrients, particularly iron and zinc, which makes them important biofortification targets. Our objective was to investigate variations in micronutrients and their relationship with grain yield components in wheat under four environments in South Africa. A population of 139 doubled haploid lines derived from a cross between cvv. Tugela-DN and Elands was phenotyped for grain iron and grain zinc concentrations and grain yield components. Heat and drought conditions at Arlington resulted in higher grain zinc concentrations and lower yield component traits; the opposite trend was observed at Bethlehem and Harrismith for both micronutrients and yield components. All traits showed transgressive segregation. Grain iron and zinc concentrations were significantly positively correlated in all four environments. The correlations between these minerals and yield components were inconsistent and ranged from significant to insignificant depending on the environment, indicating that this relationship is non-genetic. The results demonstrate that biofortification of both grain iron and grain zinc can be included as part of the breeding objectives and will not necessarily have adverse relationships with grain yield components.

Feeding Zinc-Biofortified Wheat Improves Performance, Nutrient Digestibility, and Concentrations of Blood and Tissue Minerals in Quails.

The present study aimed to investigate the effects of feeding zinc (Zn)-biofortified wheat on performance, digestibility, and concentrations of minerals in quails. Zinc biofortification of wheat has been realized in the field by ergonomically applying Zn to foliar two and three times, which increased grain Zn from 18 mg/kg (control) to 34 and 64 mg/kg. A total of 180 quails were divided into six groups, each containing 30 birds, and fed diets containing wheat grain with either 18, 34, or 64 mg/kg with or without zinc picolinate (ZnPic) supplementation. Bodyweight, feed intake, feed efficiency, and cold carcass weights were greater (P = 0.0001) when the quails were fed a diet containing the biofortified wheat-containing 64 mg Zn/kg. Nitrogen, ash, Ca, P, Zn, Cu, and Fe retentions were greater with the Zn-biofortified wheat-containing 64 mg Zn/kg (P ≤ 0.026). The nutrient excretions were low with feeding a diet containing biofortified wheat-containing 64 mg Zn/kg (P ≤ 0.023). Serum, liver, and heart Zn concentrations increased with feeding biofortified wheat-containing 64 mg Zn/kg (P ≤ 0.002). Thigh meat Fe concentrations increased with increasing Zn concentrations of the wheat samples used (P = 0.0001), whereas the liver Cu concentrations decreased with feeding the wheat-containing 64 mg Zn/kg (P = 0.004). The Zn-biofortified wheat-containing greater Zn concentrations, particularly 64 mg Zn/kg, is a good replacement for corn in the poultry diet as long as its availability and low cost for better performance, greater digestibility, and elevated tissue Zn and Fe concentrations.

Agronomic Biofortification of Zinc in Chickpea Varieties in Calcareous Soil

Background: Pulses are wonderful gift of the nature to agriculture. They provide nutrition to human beings and animals as food and feed respectively. Among the pulses, chickpea is an important rabi season crop with high acceptability and wider use in nutritional food basket. A field experiment was carried out on medium black calcareous soil at Junagadh Agricultural University, Junagadh, Gujarat during rabi season 2017-18 under saurastra condition to evaluate agronomic biofortification of zinc in chickpea (Cicer arietinum L.) varieties through seed, soil and foliar application. Methods: The experiment was laid out in factorial randomized block design with three replications. The treatment combinations comprised two varieties viz., GG 1 (V1) and GJG 3 (V2) and six zinc fortification treatments viz., control, seed treatment ZnSO4 @ 3 g kg-1 seed, 0.5% ZnSO4 foliar spray, seed treatment ZnSO4 @ 3g kg-1 seed + 0.5% ZnSO4 foliar spray, soil application ZnSO4 @ 25 kg ha-1 and soil application ZnSO4 @ 25 kg ha-1 + 0.5% ZnSO4 foliar spray. The chickpea was grown with standard package of practices. Result: The results revealed that a significant improvement in 100-seed weight, seed yield, stover yield and biological yield were observed with chickpea variety GJG 3 over GG 1. Significantly higher numbers of pods per plant (45.83) was recorded with variety GG 1. Significantly, chickpea variety GJG 3 was found superior in zinc content and uptake in seed and stover. Under agronomic strategy, zinc fortification through soil application ZnSO4 @ 25 kg ha-1 + 0.5% ZnSO4 foliar spray at flowering and pod filling stages significantly improved yield attribute and yield viz., pods per plant (55.17), seed yield (2288 kg ha-1) and stover yield (3553 kg ha-1) and quality parameters viz., protein content in seed (22.89%) and protein yield (523 kg ha-1), zinc content and uptake in seed and stover (45.98 and 37.51 ppm and 104.87 and 133.35 g ha-1, respectively) over all other zinc biofortification treatments.

Glycine-chelated zinc rather than glycine-mixed zinc has lower foliar phytotoxicity than zinc sulfate and enhances zinc biofortification in waxy corn

To determine whether high spraying concentrations of Zn sources increase the Zn concentration in waxy corn (Zea mays L. var. ceratina Kulesh) seeds without compromising agronomic performance, field experiments were conducted between 2018 and 2020. Excess ZnSO4 application caused foliar burn, barren ear tip, and grain yield loss. ZnEDTA and Glycine-chelated Zn (ZnGly) caused less foliar burn, but Glycine-mixed Zn caused more foliar burn than ZnSO4. The seed Zn concentration increased with spraying Zn concentration. ZnEDTA (≤0.8%) had a higher threshold concentration than ZnGly (≤0.4%). Nevertheless, Zn biofortification efficacy did not significantly differ between 0.4% ZnGly and 0.8% ZnEDTA, and the grain Zn recovery rate of 0.4% ZnGly was much higher than that of 0.8% ZnEDTA. Additionally, dual-isotope labelling tests confirmed that 15N-glycine and 68Zn in ZnGly interacted. In the future, chelating technology is essential for developing new Zn fertilizers to optimize Zn biofortification efficacy.

Correction to: Zinc-Solubilizing Bacteria-Mediated Enzymatic and Physiological Regulations Confer Zinc Biofortification in Chickpea (Cicer arietinum L.)

Correction to: Zinc-Solubilizing Bacteria-Mediated Enzymatic and Physiological Regulations Confer Zinc Biofortification in Chickpea (Cicer arietinum L.)

Zinc-Solubilizing Bacteria-Mediated Enzymatic and Physiological Regulations Confer Zinc Biofortification in Chickpea (Cicer arietinum L.)

Zinc-Solubilizing Bacteria-Mediated Enzymatic and Physiological Regulations Confer Zinc Biofortification in Chickpea (Cicer arietinum L.)

Zinc biofortification potential of diverse mungbean [Vigna radiata (L.) Wilczek] genotypes under field conditions.

Zinc (Zn) is an important micronutrient for crop plants and essential for human health. The Zn-deficiency is an important malnutrition problem known globally. Biofortified foods could overcome Zn deficiency in humans. Mungbean [Vigna radiata (L.) Wilczek] is an important, pulse crop frequently grown in arid and semi-arid regions of the world. Mungbean could provide essential micronutrients, including Zn to humans. Therefore, it is very important to investigate the impact of Zn fertilization on the yield and grain biofortification of mungbean. Twelve mungbean genotypes (i.e., NM-28, NM-2011, NM-13-1, NM-2006, NM-51, NM-54, NM-19-19, NM-92, NM-121-25, NM-20-21, 7006, 7008) were assessed for their genetic diversity followed by Zn-biofortification, growth and yield under control (0 kg ha-1) and Zn-fertilized (10 kg ha-1) conditions. Data relating to allometric traits, yield components, grain yield and grain Zn contents were recorded. Zinc fertilization improved entire allometric and yield-related traits. Grain yield of different genotypes ranged from 439 to 904 kg ha-1 under control and 536 to 1462 kg ha-1 under Zn-fertilization. Zinc concentration in the grains varied from 15.50 to 45.60 mg kg-1 under control and 18.53 to 64.23 mg kg-1 under Zn-fertilized conditions. The tested genotypes differed in their Zn-biofortification potential. The highest and the lowest grain Zn contents were noted for genotypes NM-28 and NM-121-25, respectively. Significant variation in yield and Zn-biofortification indicated the potential for improvement in mungbean yield and grain Zn-biofortification. The genotypes NM-28 and NM-2006 could be used in breeding programs for improvement in grain Zn concentration due to their high Zn uptake potential. Nonetheless, all available genotypes in the country should be screened for their Zn-biofortification potential.

Avenues for biofortification of zinc in barley for human and animal health: a meta-analysis

Avenues for biofortification of zinc in barley for human and animal health: a meta-analysis