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Induced mutagenesis is a quick and effective breeding strategy to enhance genetic variability, an important prerequisite for the genetic improvement of existing lentil cultivars. Lentil is an important cool season food legume with low productivity due to the low yielding potential of existing lentil cultivars. The present study aimed at increasing the yielding potential, resulted in the isolation of six high-yielding mutant lines with dense micronutrients.Two lentil varieties were treated with different doses of ethyl methanesulphonate, hydrazine hydrate, and sodium azide, followed by phenotypic selection for consecutive three generations. In the MThe isolated high-yielding mutant lines with dense micronutrients that serve as rich genetic resources could be subjected to further breeding trials. After attaining yield stability, these might be registered and released as new improved lentil varieties.

During their lifespan, sessile plants have to cope with bioavailability of the suboptimal nutrient concentration and have to constantly sense/evolve the connecting web of signal cascades for efficient nutrient uptake, storage, and translocation for proper growth and metabolism. However, environmental fluctuations and escalating anthropogenic activities are making it a formidable challenge for plants. This is adding to (micro)nutrient-deficient crops and nutritional insecurity. Biofortification is emerging as a sustainable and efficacious approach which can be utilized to combat the micronutrient malnutrition. A biofortified crop has an enriched level of desired nutrients developed using conventional breeding, agronomic practices, or advanced biotechnological tools. Nutrient homeostasis gets hampered under nutrient stress, which involves disturbance in short-distance and long-distance cell-cell/cell-organ communications involving multiple cellular and molecular components. Advanced sequencing platforms coupled with bioinformatics pipelines and databases have suggested the potential roles of tiny signaling molecules and post-transcriptional regulators, the microRNAs (miRNAs) in key plant phenomena including nutrient homeostasis. miRNAs are seen as emerging targets for biotechnology-based biofortification programs. Thus, understanding the mechanistic insights and regulatory role of miRNAs could open new windows for exploring them in developing nutrient-efficient biofortified crops. This review discusses significance and roles of miRNAs in plant nutrition and nutrient homeostasis and how they play key roles in plant responses to nutrient imbalances/deficiencies/toxicities covering major nutrients-nitrogen (N), phosphorus (P), sulfur (S), magnesium (Mg), iron (Fe), and zinc (Zn). A perspective view has been given on developing miRNA-engineered biofortified crops with recent success stories. Current challenges and future strategies have also been discussed.

Key message A genomic prediction model successfully predicted grain Zn concentrations in 3000 gene bank accessions and this was verified experimentally with selected potential donors having high on-farm grain-Zn in Madagascar. Abstract Increasing zinc (Zn) concentrations in edible parts of food crops, an approach termed Zn-biofortification, is a global breeding objective to alleviate micro-nutrient malnutrition. In particular, infants in countries like Madagascar are at risk of Zn deficiency because their dominant food source, rice, contains insufficient Zn. Biofortified rice varieties with increased grain Zn concentrations would offer a solution and our objective is to explore the genotypic variation present among rice gene bank accessions and to possibly identify underlying genetic factors through genomic prediction and genome-wide association studies (GWAS). A training set of 253 rice accessions was grown at two field sites in Madagascar to determine grain Zn concentrations and grain yield. A multi-locus GWAS analysis identified eight loci. Among these, QTN_11.3 had the largest effect and a rare allele increased grain Zn concentrations by 15%. A genomic prediction model was developed from the above training set to predict Zn concentrations of 3000 sequenced rice accessions. Predicted concentrations ranged from 17.1 to 40.2 ppm with a prediction accuracy of 0.51. An independent confirmation with 61 gene bank seed samples provided high correlations (r = 0.74) between measured and predicted values. Accessions from the aus sub-species had the highest predicted grain Zn concentrations and these were confirmed in additional field experiments, with one potential donor having more than twice the grain Zn compared to a local check variety. We conclude utilizing donors from the aus sub-species and employing genomic selection during the breeding process is the most promising approach to raise grain Zn concentrations in rice.

Made available in DSpace on 2022-05-01T13:57:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Hidden hunger, known as micronutrient deficiency in humans, affects about 2 billion people worldwide. One of the ways to minimize hidden hunger is through genetic biofortification. This study aimed to evaluate the natural genotypic variation of micronutrients in upland rice grains and agronomic traits to select genetic material for further agronomic and genetic biofortification aiming high density of micronutrients in grains. The experimental design used was randomized blocks, with treatments consisting of 8 upland rice genotypes. The agronomic traits and the content of iron, zinc and copper in the rice genotypes grains were evaluated. The genotypes OSVR15001, OSVR15029, OSVR15038 and OSVR15047 did not differ statistically from the commercial cultivar IAC 203 in the two agricultural years and can be used as a complement in the production of upland rice. The OSVR15047 genotype maintained high Cu content in the grains and elevated grain yield in the two years of cultivation, being able to be used in genetic improvement for the emergence of superior genotypes. The OSVR15042 genotype was the only one that maintained a high Zn concentration in the grains in both years, also being able to be used for genetic biofortification. Our results contribute to the selection of genotypes that have good yield and good nutritional content in grains, which can help to minimize the effects of hidden hunger and increase the health of the population. Departament of Crop Production College of Agricultural and Technological Sciences São Paulo State University (UNESP), Rod. Cmte João Ribeiro de Barros, km 651 - Bairro das Antas, SP College of Agricultural and Veterinary Sciences São Paulo State University (UNESP), SP Department of Plant Science Food Technology and Economic Partner School of Natural Sciences and Engineering São Paulo State University (Unesp), SP Departament of Crop Production College of Agricultural and Technological Sciences São Paulo State University (UNESP), Rod. Cmte João Ribeiro de Barros, km 651 - Bairro das Antas, SP College of Agricultural and Veterinary Sciences São Paulo State University (UNESP), SP Department of Plant Science Food Technology and Economic Partner School of Natural Sciences and Engineering São Paulo State University (Unesp), SP

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.

Malnutrition causes diseases, immune system disorders, deterioration in physical growth, mental development, and learning capacity worldwide. Micronutrient deficiency, known as hidden hunger, is a serious global problem. Biofortification is a cost-effective and sustainable agricultural strategy for increasing the concentrations or bioavailability of essential elements in the edible parts of plants, minimizing the risks of toxic metals, and thus reducing malnutrition. It has the advantage of delivering micronutrient-dense food crops to a large part of the global population, especially poor populations. Agronomic biofortification and biofertilization, traditional plant breeding, and optimized fertilizer applications are more globally accepted methods today; however, genetic biofortification based on genetic engineering such as increasing or manipulating (such as CRISPR-Cas9) the expression of genes that affect the regulation of metal homeostasis and carrier proteins that serve to increase the micronutrient content for higher nutrient concentration and greater productivity or that affect bioavailability is also seen as a promising high-potential strategy in solving this micronutrient deficiency problem. Data that micronutrients can help strengthen the immune system against the COVID-19 pandemic and other diseases has highlighted the importance of tackling micronutrient deficiencies. In this study, biofortification approaches such as plant breeding, agronomic techniques, microbial fertilization, and some genetic and nanotechnological methods used in the fight against micronutrient deficiency worldwide were compiled.

Zinc and iron play a vital role in the plant growth and development process because they act as a cofactor for different enzymes that are involved in various important metabolic activities like photosynthesis, respiration, chlorophyll, and carotenoid synthesis. There are various mechanisms evolved by crop plants for uptake, transportation, absorption, and accumulation of iron (Fe) and zinc (Zn) in plant parts that are further utilized for nourishing humans. Furthermore, it is estimated that about three billion people in developing countries are suffering from iron and zinc deficiency which is generally observed in the case of children and women. Biofortification includes various techniques that increase the concentration of different micronutrients and vitamins in edible plants and increasing the bioavailability by decreasing anti-nutritional factors. Iron and zinc biofortified crops will provide a ray of hope in combating nutritional deficiency disorder across developing countries. This review article describes the biofortification of Poaceae crops like wheat, rice, and oats for high Fe and Zn content by utilizing plant breeding and biotechnological approaches.

Iron (Fe) and Zinc (Zn) are vital micronutrients for plants and their deficiency causes severe impairments in physiological and biochemical responses of plants. In response to stress emerging due to their deficiency, plants evolve different strategies to regulate the homeostasis network to ensure optimum Fe and Zn uptake. Fe and Zn biofortification of food crops offer a promising approach to alleviate the malnutrition caused due to their deficiency. However, the complex mechanism underlying the fine-tuned processes of mineral uptake, transport and accumulation in seeds involve a multitude of regulatory insights including alteration in root morphology, nutrient partitioning and subsequent accumulation in seeds mediated by different transporters, chelators, transcription factors and post transcriptional regulation which act in a coordinated manner to elicit responses in plants regulating Fe and Zn acquisition. These insights into the regulatory mechanisms will provide a better understanding for improving the Fe- and Zn- use efficiencies, maximization of Fe and Zn bioavailability in edible parts, the deficiency tolerance attributes and subsequent Fe and Zn- biofortification in plants.

This study investigated the effect of selenium (Se) biofortification on the mineral composition, phenolic content and antioxidant properties of Jute leaf (Corchorus olitorius). Jute seeds were cultivated in four groups containing 0%, 0.01%, 0.05% and 0.1% Se-fortified organic fertilizer. The leaves were harvested at maturity and the mineral content, total phenol and flavonoid contents were determined. In vitro antioxidant properties of the leaves shown by their free radical scavenging abilities, reducing property, Fe2+ chelating ability, inhibition of Fenton reaction and lipid peroxidation were also assayed. Se content significantly increased from 0.18 ± 0.01 mg/100 g in 0% fortification group to 0.4 ± 0.03 mg/100 g in 0.1% fortification. Total phenol and flavonoid contents with the antioxidants properties increased at 0.05% fortification but reduced at 0.1% fortification. The result suggests that Jute leaf bioaccumulation of Se at 0.05% Se biofortification optimally influenced its mineral, phenolic contents and antioxidant properties.

Plant growth promoting selenorhizobacteria have the multi-capacity to colonize the leguminous plant roots for promoting their growth by certain mechanisms. Present study was carried out to evaluate selenium biofortification in Phaseolus vulgaris under pot study through selenocysteine methyltransferase (SMT) gene expression. Isolation and identification through 16 S rRNA gene sequencing identified MPJ9 as Pantoea dispersa, which was also found to have the capacity to enhance selenium content (3.27-fold) in P. vulgaris as compared to control plants. Fourier-transform infrared (FTIR) spectroscopy analysis of selenium enriched plant revealed the presence of selenocompound in plant and showing the absorption peaks at 996.93 cm−1 and 2310.80 cm−1 indicating existence of C=Se and Se-H groups, respectively. Thin layer chromatography (TLC) analysis of selenium enriched plant for presence of S MT activity was found with Rf value 0.58. Quantitative real-time polymerase chain reaction results of test plant revealed the relative SMT expression in different parts of selenium enriched plants to be in the range of 1.24-fold to 2.80-fold. The maximum SMT expression level was observed 2.80-fold in leaves of selenium enriched plant. Results indicating that the leaves of selenium enriched plant had more capacity to accumulate selenium as selenocompound. Overall growth of plants through inoculation was significantly greater than the control plant, indicating the positive effect of selenorhizobacteria for sustainable crop improvement.

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

The foliar application of selenium (Se) is an effective method for biofortification of Se in crop grains in order to provide sufficient Se for human health. As a staple food in China, the foxtail millet (Setaria italica L.), which had been Se biofortification, would be helpful to overcome Se deficiency in the diet. The Se fertilizer and its application technology are vital for reducing environmental risk while enriching selenium. Hence, the Se-rich nutrient solution developed by ourselves was used, and the effect of its amount and growth stage applied on the accumulation of Se in grains of foxtail millet (Setaria italica L.) was studied in the present study. The results were as follows: (1) the Se concentration in grains increased with the Se application rate increasing, and the highest Se concentration in grains was 1.83 mg kg-1 at the sprayed concentration of 61.5 gSe hm-2; (2) the accumulation of Se sprayed in the grain-filling stage was 1.3-1.6 times higher than that in the joint stage; and (3) the organ damage could be found under low Se/S ratio, which happened in the rice leaves when the Se rate was higher than 76.875 gSe m-2 with the low sulfate application compared with the formulation. This Se-rich nutrient solution could be used to produce the Se-rich millet grains and foliar application in the reproductive stage to produce qualified Se-rich millet.

More than 2 billion people worldwide suffer from micronutrient malnutrition, sometimes known as hidden hunger. Zn malnutrition affects around a third of the world's population. The physicochemical features of soil, which limit the availability of Zn to plants, cause Zn deficiency. The eating habits of certain populations are more depended on Zn-deficient staple foods. Due to the high expense and certain interventions such as diet diversification, zinc supplementation and food fortification cannot be achieved in disadvantaged populations. Biofortification is the most practical technique for alleviating Zn malnutrition. Seed priming with nutrients is a promising biofortification approach for edible crops. Seed nutripriming with zinc is a cost-effective and environmentally benign approach of biofortification. Seeds can be nutriprimed with Zn using a variety of methods such as Zn fertilisers, Zn chelated compounds and Zn nanoparticles. Nutripriming with nanoparticles is gaining popularity these days due to its numerous advantages and vast biofortification potential. Seeds enriched with Zn also aid plant performance in Zn-deficient soil. Zn an essential trace element can regulate physiological, biochemical and molecular processes of plant cells and thus can enhance germination, growth, yield and bioavailable Zn in edible crops. Moreover, zinc emerges as an important element of choice for the management of COVID-19 symptoms.

The dessert bananas genotype are typically AA, AAA, and AAB, while ABB is classified as cooking bananas. Their nutritional content can be accessed much better than cooking bananas by the human body because they can be consumed directly without processing. This present study aimed to investigate the metabolite profiles of the ripe pulp of ten Indonesian dessert bananas cultivars represents the commercial interest and unpopular cultivars groups by UHPLC-Q-Orbitrap HRMS. They were Ambon Putih, Ambon Kuning, Ambon Badak, Ambon Lumut, Raja Sereh, Raja Bulu, Lampung, Papan, Rejang, and Udang. Nineteen metabolites were putatively identified in all of the cultivars studied. The main groups were fatty acids and the others catecholamine, quinone, phenol, flavonoid, cinnamic acid, organic acid, indole, and amino acid groups. Some of them were important bioactive compounds such as linolenic acid, palmitelaidic acid, linoleic acid, p-coumaric acid, dopamine, myricetin-deoxyhexose-hexoside, eugenol, 1,4-benzoquinone, and antroquinonol. The PCA score and loading plot showed the ten cultivars were separated into two groups based on linolenic acid as the first (PC1, 57%) and p-coumaric acid (PC2, 38%) as the second principal component with the 95% total variance explained. There was no relationship between PCA grouping and the genome group in terms of composition and metabolite content. These results provide valuable information for plant breeding programs, especially in banana biofortification for the future.

Agronomic selenium (Se) biofortification of grain crops is considered the best method for increasing human Se intake, which may help people alleviate Se-deficiency. To investigate the efficiency of agronomic Se biofortification of oat, four Se fertilizer application treatments were tested: topsoil (T), foliar (S), the combination of T and S (TS), and control without Se application (CK). Compared with CK, TS significantly increased the 1000-grain weight, grain yield, Se contents in all parts of oats, contents of soil available N, K, and organic matter by 18%, 8.70%, 19.7-60.2%, 6.00%, 8.02%, and 17.95%, respectively. Leaves, roots, and ears had the highest conversion rate of exogenous Se in S (644.63%), T (416.00%), and TS (273.20%), respectively. TS also increased the activities of soil urease, alkaline phosphatase, and sucrose and the diversity of soil bacterial communities. TS and T increased the relative abundance of bacteria involved in the decomposition of organic matter, such as Actinobacteria, Gemmatimonadetes, Chloroflexi, and Bacteroidetes positively correlated with soil nutrients and enzyme activities, and reduced Proteobacteria and Firmicutes negatively correlated with them, Granulicella, Bacillus, Raoultella, Lactococcus, Klebsiella, and Pseudomonas. Furthermore, TS significantly increased the relative abundance of Planctomycetes, Chlorobi, Nitrospinae, Nitrospirae, Aciditeromonas, Gemmatimonas, Geobacter, and Thiobacter. T significantly increased the abundance of Lysobacter, Holophaga, Candidatus-Koribacter, Povalibacter, and Pyrinomonas. S did not significantly change the bacterial communities. Thus, a combined foliar and soil Se fertilizer proved conducive for achieving higher yield, grain Se content, and improving Se transport, the diversity of rhizosphere bacterial community, and bacterial functions in oats.

Key message Root-specific expression of a cytokinin-degrading CKX gene in maize roots causes formation of a larger root system leading to higher element content in shoot organs. Abstract The size and architecture of the root system is functionally relevant for the access to water and soil nutrients. A great number of mostly unknown genes are involved in regulating root architecture complicating targeted breeding of plants with a larger root system. Here, we have explored whether root-specific degradation of the hormone cytokinin, which is a negative regulator of root growth, can be used to genetically engineer maize (Zea mays L.) plants with a larger root system. Root-specific expression of a CYTOKININ OXIDASE/DEHYDROGENASE (CKX) gene of Arabidopsis caused the formation of up to 46% more root dry weight while shoot growth of these transgenic lines was similar as in non-transgenic control plants. The concentration of several elements, in particular of those with low soil mobility (K, P, Mo, Zn), was increased in leaves of transgenic lines. In kernels, the changes in concentration of most elements were less pronounced, but the concentrations of Cu, Mn and Zn were significantly increased in at least one of the three independent lines. Our data illustrate the potential of an increased root system as part of efforts towards achieving biofortification. Taken together, this work has shown that root-specific expression of a CKX gene can be used to engineer the root system of maize and alter shoot element composition.

Carbon profiling of heterotrophic microbial inoculants is worthwhile strategy for formulating consortium-based biofertilizers. Consortium-based biofertilizers are better than single strain-based biofertilizers for sustaining agricultural productivity and enhancing micronutrient concentration in grains. Currently, we investigated catabolic diversity among microbes using different carbon sources and certain enzyme activities. A field experiment was also carried to evaluate the synergistic effect of selected lentil Rhizobia and plant growth promoting rhizobacteria strains on lentil growth, yield, nitrogen fixation, and Fe-content in seeds. On the basis of carbon profiling Bacillus sp. RB1 and Pseudomonas sp. RP1 were selected for synergistic study with lentil Rhizobium-Rhizobium leguminosarum subsp. viciae RR1. Co-inoculation of Rhizobium with Bacillus sp. RB1 and Pseudomonas sp. RP1 significantly enhanced the plant height, number of pods per plant, seed yield, number of nodules per plant, nitrogenase activity and Fe biofortification in seed over the single Rhizobium inoculation or dual combination of Rhizobium + RB1 or RP1.The response of single Rhizobium inoculation or co-inoculation of Rhizobium with RB1 and/or RP1 at 50% RDF was almost similar or higher than full dose of recommended N:P:K with respect to lentil yield and Fe biofortification in seed. This deciphered grouping of microbial strains for formulation of microbial consortia-based biofertilizers and revealed the promise of consortium of Rhizobium and plant growth promoting rhizobacteria in improving the biological yield and enhancing the Fe content of lentil seed.

Zinc (Zn) deficiency is a widespread micro-nutritional disorder in humans. The present research aimed at investigating the enzymatic and physiological roles of zinc solubilizing bacteria (ZnSB) to solubilize the insoluble form of Zn and in increasing Zn content in chickpea. Bacterial strains (50) were isolated from chickpea rhizosphere and were screened in vitro for their Zn solubilizing efficiency by culturing on Tris-minimal agar medium supplemented with insoluble Zn compounds (ZnO and ZnCO3). Initially, six potential ZnSB (ZnSB7, Paenibacillus polymyxa; ZnSB11, Ochrobactrum intermedium; ZnSB13, Bacillus cereus; ZnSB21, Streptomyces; ZnSB24, Stenotrophomonas maltophilia; and ZnSB25, Arthrobacter globiformi) were selected based on Zn solubilization halo, Zn solubilization efficiency, and quantitative solubilized Zn. These strains were further assayed for higher phosphate solubilizing index, available phosphorus, and IAA production, and characterized by 16S rRNA gene sequence analysis. A pot experiment was then conducted to assess the effects of six promising ZnSB as seed inoculation on growth traits and Zn contents in chickpea. Seed inoculation of ZnSB13 exhibited maximum phosphatase, dehydrogenase, and microbial activities in plant rhizosphere, thereby, caused a maximum availability of soil Zn. The positive effects of ZnSB13 inoculation were also revealed on maintained higher net photosynthetic rate, transpiration rate, and stomatal conductance and water use efficiency that responsible for considerable increase in dry biomass, nodulation, and yield of chickpea. Furthermore, inoculation of ZnSB13 exhibited maximum increase in grain N, grain P, and Zn contents in root, shoot, and grains of chickpea. Thus, ZnSB inoculation could be an effective approach to solubilize the unavailable soil Zn, and making them valuable for improving Zn biofortification in chickpea.

Iron deficiency is a serious global issue, particularly in developing countries. Individuals are suffering from iron deficiency due to monotonous consumption of cereal based diets, which are unable to provide adequate amounts of iron. The majority of these people cannot afford a diversified diet, iron supplements and iron fortified food products. The development of iron biofortified potatoes could provide a sustainable solution to this problem. The leading strategies for crop biofortification include agronomic practices, plant breeding and transgenic approaches. Previous reports have highlighted that agronomic practices are not very effective for iron biofortification of potato. However, extensive genetic variability for iron content in potato gene pool makes it an ideal crop for iron biofortification through genetic approaches. Therefore, genotypes with high iron content could be used as parental lines in potato breeding programs. The screening of genes or QTLs responsible for high iron content in these genotypes could pave the way for the development of iron biofortified potatoes through marker-assisted selection, speed breeding and transgenic approaches.

AimAgronomic biofortification of fruit with iodine (I) has become an innovative approach in contemporary agriculture. In this study, we evaluated the influence of soil- and foliar I applications on absorption of this nutrient by apple (Malus domesticaBorth.) trees, as well as on growth and yield responses of the plants.MethodsIn 2018–2019, ‘Red Jonaprince’ apple trees, grown on sandy loam soil, were treated with potassium iodide (KI) or K-iodate (KIO3) through soil application (at a rate of 4 kg, 8 kg or 12 kg I ha−1) or preharvest sprays (at a rate of 0.5 kg, 1 kg or 1.5 kg I ha−1).ResultsThe I sprays increased apple I contents to the targeted range of 50–100 µg 100 g−1fresh weight and even to the recommended daily intake of I for adults (the KI sprays at rates of 1 kg and 1.5 kg I ha−1). Although the I sprays caused leaf injuries, they did not affect tree growth and yield. However, the spray of KI and KIO3at the highest rate decreased the soluble solid concentration in fruit. For soil-supplied trees with I, an increase in apple I concentration was found only in the first year of the study.ConclusionsApple tree is a suitable target plant for agronomic I biofortification, and from the economic point of view, the spray of KI or KIO3at a rate of 0.5 kg I ha−1should be recommended in orchards.

Pearl millet is a major staple cereal crop worldwide and genetic biofortification with enhanced grain iron (Fe) and zinc (Zn) concentrations are ongoing efforts to combat micronutrient malnutrition. There is limited information on the nature and magnitude of gene action for Fe and Zn densities, yield and its component traits in pearl millet. Therefore, generation mean analysis was carried out with six basic generations viz., P1, P2, F1, F2, BC1 and BC2 derived from nine crosses using 18 parental lines of diverse pedigree. Analysis of variance revealed that genotypes were significant for days to flowering, days to maturity, panicle length, panicle girth, plant height, number of productive tillers per plant, grain yield per plant, 1000 grain weight, grain iron content and grain zinc content in all the crosses while, non significant for days to maturity and 1000 grain weight in crosses J 2340 × 30291 and ICMB 10444 × ICMB 97222, respectively. Generation mean analysis studies revealed that inheritance of grain yield per plant and contributing traits were governed by additive, dominance and varied types of nonallelic interactions. The additive and varied nonallelic interactions were observed in few crosses for days to maturity, plant height, panicle girth, 1000 grain weight and grain iron content. Similarly, dominance and varied types of nonallelic interactions were present in limited crosses for days to flowering, days to maturity, plant height, number of productive tillers per plant, panicle length and panicle girth. The dominance gene action was observed in cross J 2372 × 30610 for number of productive tillers per plant and J 2454 × 30348 for panicle length while, additive gene action was exhibited in cross 30727 × J 2523 for days to maturity and J 2340 × 30291 for panicle length in pearl millet. Presence of duplicate epistasis in most of the crosses for all the traits except number of productive tillers per plant indicated prevalence of greater genetic diversity. While, complementary epistasis was restricted to limited crosses for days to flowering, plant height, number of productive tillers per plant, panicle length and grain yield per plant. For grain Fe and Zn content varied nonallellic interactions in combination with additive and dominance gene actions played a major role in influencing the trait. However, nonallelic gene interactions with only additive (d) gene actions played a major role in genetic control of grain iron content in crosses J 2340 × 30291, 30127 × J 2556, ICMB 10444 × ICMB 97222 and 30843 × ICMB 98222. Moreover, one cross 30725 × ICMB 05333 showed only additive gene effect and additive × dominance component of genic interaction for grain zinc content. This information can be utilized in developing pearl millet lines with high grain Fe and Zn content.

QTNs significantly associated to nine mineral content in grains of common bean were identified. The accumulation of favorable alleles was associated with a gradually increasing nutrient content in the grain. Biofortification is one of the strategies developed to address malnutrition in developing countries, the aim of which is to improve the nutritional content of crops. The common bean (Phaseolus vulgaris L.), a staple food in several African and Latin American countries, has excellent nutritional attributes and is considered a strong candidate for biofortification. The objective of this study was to identify genomic regions associated with nutritional content in common bean grains using 178 Mesoamerican accessions belonging to a Brazilian Diversity Panel (BDP) and 25,011 good-quality single nucleotide polymorphisms. The BDP was phenotyped in three environments for nine nutrients (phosphorus, potassium, calcium, magnesium, copper, manganese, sulfur, zinc, and iron) using four genome-wide association multi-locus methods. To obtain more accurate results, only quantitative trait nucleotides (QTNs) that showed repeatability (i.e., those detected at least twice using different methods or environments) were considered. Forty-eight QTNs detected for the nine minerals showed repeatability and were considered reliable. Pleiotropic QTNs and overlapping genomic regions surrounding the QTNs were identified, demonstrating the possible association between the deposition mechanisms of different nutrients in grains. The accumulation of favorable alleles in the same accession was associated with a gradually increasing nutrient content in the grain. The BDP proved to be a valuable source for association studies. The investigation of different methods and environments showed the reliability of markers associated with minerals. The loci identified in this study will potentially contribute to the improvement of Mesoamerican common beans, particularly carioca and black beans, the main groups consumed in Brazil.

Staple grains with low levels of provitamin A carotenoids contribute to the global prevalence of vitamin A deficiency and therefore are the main targets for provitamin A biofortification. However, carotenoid stability during both seed maturation and postharvest storage is a serious concern for the full benefits of carotenoid biofortified grains. In this study, we utilized Arabidopsis as a model to establish carotenoid biofortification strategies in seeds. We discovered that manipulation of carotenoid biosynthetic activity by seed-specific expression of Phytoene synthase (PSY) increases both provitamin A and total carotenoid levels but the increased carotenoids are prone to degradation during seed maturation and storage, consistent with previous studies of provitamin A biofortified grains. In contrast, stacking with Orange (ORHis), a gene that initiates chromoplast biogenesis, dramatically enhances provitamin A and total carotenoid content and stability. Up to 65- and 10-fold increases of β-carotene and total carotenoids, respectively, with provitamin A carotenoids composing over 63% were observed in the seeds containing ORHis and PSY. Co-expression of Homogentisate geranylgeranyl transferase (HGGT) with ORHis and PSY further increases carotenoid accumulation and stability during seed maturation and storage. Moreover, knocking-out of β-carotene hydroxylase 2 (BCH2) by CRISPR/Cas9 not only potentially facilitates β-carotene accumulation but also minimizes the negative effect of carotenoid over production on seed germination. Our findings provide new insights into various processes on carotenoid accumulation and stability in seeds and establish a multiplexed strategy to simultaneously target carotenoid biosynthesis, turnover, and stable storage for carotenoid biofortification in crop seeds.

Iron deficiency is one of the most prevailing micronutrient deficiencies throughout the globe. Iron malnutrition affects billions of people around the world especially children and pregnant women. Its deficiencies can be overcome through microbial biofortification: a process of deliberately increasing desirable nutrients in crop plants. Plant growth-promoting rhizobacteria (PGPR) can improve iron content in edible plant tissues through different direct and indirect mechanisms. Adding plant growth regulators along with rhizobacteria makes it a novel fortification approach. In the current experiment, the interactive effect of two bacterial isolates (O-13 & K-10) alone and in consortium with l-tryptophan in the presence of iron sulfate was evaluated on growth, physiology, tuber characteristics, and iron concentration in potato (Solanum tuberosum L.). Results revealed that inoculation with PGPR and plant growth regulator (PGR) significantly improved the plant height, straw yield, and the number of tubers per plant. Potato (Solanum tuberosum L.) tuber characteristics (starch content, vitamin-C, relative water content) were also improved significantly. O-13, K-10, and l-tryptophan had significantly improved the iron concentration up to 20.59, 33.12, and 28.95%, respectively. However, inoculation with the microbial consortium and l-tryptophan showed a significant increase of up to one-fold in the iron concentration of potato (Solanum tuberosum L.) as compared with uninoculated control. The results suggest that rhizobacteria can help the plant to uptake nutrients from the soil. These findings concluded on the fact that the interactive effect of microbial assisted biofortification and plant growth regulator is a novel, promising, and cost-effective approach to mitigate micronutrient deficiencies especially in resource-limited countries.

Zinc biofortification through agronomic and/or genetic approaches is one of the strategies to enrich food with this essential element to fulfil nutritional requirements in poor diets. This study aimed to unravel the physiological basis of differential tuber-Zn concentration between potato cultivars and to identify the major source(s) of Zn to the tubers. Two potato cultivars, accumulating high (Lady Rosetta) and low (Cara) tuber-Zn, were evaluated and the patterns of biomass and Zn accumulation between organs assessed over the growth period. Furthermore, Zn partition in reciprocal grafted plants and in sixteen F1 genotypes following a cross between those cultivars was assessed at harvest. The cultivars differed in Zn-concentration, Zn-content and biomass partitioning between organs, although total plant-Zn content was comparable (4.7 and 5.1 mg Zn/plant for Cara and Lady Rosetta, respectively). At harvest the relative amount of Zn retained in roots, stems, leaves and tubers was 2 %,25 %,5 % and 68 % for Cara and 1 %,17 %,5 % and 77 % for Lady Rosetta. The differential tuber-Zn was associated with internal Zn distribution between shoots and tubers. Lady Rosetta translocated higher amounts of Zn to the tubers while Cara accumulated relatively more Zn in the stems associated with higher stem biomass. Remobilization of Zn from leaves and stems, and continuous root to xylem-phloem transfers during tuber bulking were the major sources of Zn supply to the tubers. This study suggests that the potato stem plays an important role in regulating Zn distribution and also as a site for Zn deposition.

Ketocarotenoid–biofortified crops are required as natural additives with respect to their Rubi-like reddish color and strong antioxidative properties for foods and feeds. They can be an alternative means of microalgal and bacterial systems and do not depend on chemical synthesis, providing safe, sustainable, and processing-free platforms. To reach sufficient commercial demands, different metabolic engineering strategies have been used in diverse crop plants. In this study, we summarized the current achievements for de novo production of ketocarotenoids in major crops and described host crop-specific tactics to optimize the ketocarotenoid biosynthetic pathway, considering the following different levels and types of carotenoid being accumulated as precursors: lutein and zeaxanthin in maize seeds; lutein in rice seeds, canola seeds, soybean seeds, and tobacco flowers; zeaxanthin in potato tubers; β–carotene in carrot roots; and lycopene in tomato fruits. This study suggests prospects for the advanced performance of ketocarotenoid biofortification in crops in two crucial points: host crop cultivar and the elaborately designed genetic strategies. The latter includes an increase in the total carotenoid capacity by co-consideration to supply precursors and stabilizers, the prevention of metabolite loss in competing or catabolic pathways or both pathways, and the sensible choice of genes and genetic elements for optimal expression. Furthermore, progresses in synthetic biology and new biotechnology, such as genome editing, could accelerate the development of high-valued “Rubi Crops,” which satisfy the nutritional and functional needs of humans and animals.

Background and aims This study explores the use of energy dispersive x-ray fluorescence (EDXRF) for screening micronutrient concentrations in lentil and sorghum grain for biofortification breeding programs. Methods Lentil and sorghum seed was provided from biofortification breeding programs and analysed with inductively coupled plasma mass spectrometry (ICP-MS) to determine the reference concentration levels of Ca, Mn, Fe, Cu and Zn. A subset of these samples was used to establish the EDXRF calibration and another subset used for validation of the method. Results The results show the EDXRF analyses of the lentil and sorghum are not significantly different to the reference ICP-MS for all elements analysed, except for Mn with %RSD of replicate analysis Conclusions EDXRF analysis enables rapid and accurate analysis of Ca, Mn, Fe, Cu and Zn in lentil and sorghum.

Nutritional status of people can be improved by enhancing zinc (Zn) and iron (Fe) content in cereals used as staple mainly in poor resource countries. Zinc and Fe were applied through soil and foliage in a study to biofortify wheat grains. Foliar application of both micronutrients increased the growth and grain vigor as compared to soil application and control. Also, foliar application significantly enhanced Zn and Fe concentration in grain pre-dominantly localized in aleurone layer. Exogeneous application of Fe and Zn was found beneficial for plant growth and enhanced Fe and Zn concentrations in grain, however aleurone layer and embryonic region of the grain showed higher accumulations than that in endosperm. Therefore, understanding of physiological and molecular pathways for uptake and localization of Fe and Zn in wheat grains need to be critically examined to improve their concentration in grain to achieve the biofortification targets.

Improving the chemical and physical properties of saline soils is crucial for the sustainable production of sugar beet and efficient processing of beet sugar. Here, the impacts of the application of treated filter cake on sugar beet biofortification under saline soil and sugar losses into molasses during beet sugar processing were evaluated for the first time. The application of treated filter cake significantly reduced K%, Na% and α-amino-N while enhanced sucrose content and quality index of beet root juice. Consequently, sugar loss percentage, sugar loss yield and relative sugar loss yield were reduced, whereas recoverable sugar yield was enhanced. Linear regression analysis revealed that quality index and sugar loss yield were increased, whereas sugar loss percentage and relative sugar loss yield were reduced in response to the reduction of soil Na + content accompanied with increasing Ca 2+ content in the soil increased. The results provide treated filter cake as a promising amendment for saline soils remediation for improving biofortification of sugar beet and reducing sugar losses during beet sugar processing.

Children’s diets can have major implications for a wide range of diseases and their development outcomes. In Africa, micronutrient deficiency remains a major challenge and affects the health and development of vulnerable populations, especially children. A major effort to combat micronutrient deficiency has targeted biofortification of staple foods, with greatest potential being registered in the enrichment of, among others, sweetpotato with beta carotene—a precursor for vitamin A. However, overcoming vitamin A deficiency is made all the more complicated by children’s general resistance to unfamiliar foods. We report the results of a field experiment in Nigerian schools designed to use behavioral techniques to promote consumption of an unfamiliar food: the pro-vitamin A rich orange-fleshed sweetpotato. We find that children eat more, on average, when the sweetpotato is introduced alongside behavioral nudges such as songs or association with aspirational figures. These results appear to conform to results found in a developed country context.

Zinc-solubilizing bacteria (ZSB) are potential and ideal substitutes for Zn supplement. Currently, limited reports are available on the bacteria displaying capability to transform insoluble forms of zinc (Zn) to an available form. Therefore, attempts were made to identify and characterize Zn-solubilizing strains from chickpea rhizosphere for growth promotion and Zn biofortification. Sixty-one bacteria isolated from rhizosphere of chickpea from different parts of Indo-Gangetic plains (IGP) of India were screened for Zn-solubilizing capabilities by cultivating on BTG medium supplemented with ZnO, Zn3(PO4)2, and ZnCO3. Two potential ZSB (BT3 and CT8) were chosen based on their zinc solubilization index and zinc solubilization efficiency and later identified by 16S rRNA gene sequence analysis. In vitro assays were performed to determine their plant growth-promoting attributes. PCR assay was performed to confirm the presence of zinc uptake regulator (zur) gene in potential strains. Pot experiments were carried out to evaluate the effect of two potential ZSB (BT3 and CT8) on growth promotion and Zn biofortification in chickpea. Atomic absorption spectroscopy was employed to determine the Zn content in the plants. Out of twenty-four ZSB, only two strains (BT3 and CT8) were able to solubilize all the three Zn sources. Isolate, BT3 released maximum concentration of Zn from ZnCO3 (150.2 ± 1.1 mg l−1), while CT8 released maximum from ZnO (130.2 ± 1.2 mg l−1) and Zn3(PO4)2 (116.5 ± 1.2 mg l−1), respectively. The pH of medium was strongly acidic which ranged from 5.2 to 3.9, and the organic acid analysis revealed hexanoic acid, pentanoic acid, and mandelic acids as prime organic acids produced by isolates. The presence of zur genes indicated the involvement of zur-mediated molecular mechanisms in these strains. These isolates also showed plant growth-promoting traits such as production of indole acetic acid (IAA), ammonia, siderophores, and phosphate solubilization. The 16S rRNA sequence analysis revealed that both the isolates had close similarity with Bacillus altitudinis. Inoculation of isolates BT3 and CT8 improved the growth parameters of chickpea and increased the plant’s Zn uptake by 3.9–6.0%. B. altitudinis strains (BT3 and CT8) show excellent capabilities to solubilize insoluble Zn compounds like oxides, phosphates, and carbonates of Zn, making them valuable source for improving Zn uptake and growth of chickpea.

Background and Aim Success in agronomic biofortification of maize and wheat is highly variable. This study aimed to elucidate the differences in uptake and translocation of foliar-applied zinc (Zn) in maize (Zea mays L.) and wheat (Triticum aestivum L.) using different experimental approaches. Methods Old leaves of plants cultured with low or adequate Zn supply in soil were treated with natural Zn (as ZnSO4) or enriched stable isotope Zn-70 as SO4 salt. Treated leaves, and the remaining untreated shoot and roots were analyzed for Zn using quantitative (ICP-OES and ICP-MS after acid digestion) and qualitative (fluorescence microscopy after Zinpyr-1 staining) techniques. Results Application of Zn to a single old leaf resulted in significantly higher increments in Zn concentration of the treated leaf, remaining untreated shoot and roots in wheat than in maize, particularly under low Zn supply. The relative Zn uptake (i.e., the portion of Zn-70 taken up by the treated leaf) was also estimated to be significantly higher in wheat than maize, irrespective of the rate of Zn supply to plants. Higher uptake and translocation of Zn in wheat compared to maize was also visualized and demonstrated by using Zinpyr-1 fluorescent dye. Conclusions Our results conclude that wheat is superior to maize in terms of leaf penetration and uptake, as well as subsequent translocation of foliar-applied Zn, therefore, the agronomic biofortification potential is better for wheat than for maize.

The aims of this work were (i) to find a soil indicator to predict durum wheat yield response to Zn fertilization, (ii) to compare the effect of various Zn fertilization strategies on wheat yield and Zn biofortification in calcareous Vertisols of southern Spain, and (iii) to assess the effect of these Zn fertilization strategies on crop P uptake (durum and bread wheat). Different Zn fertilization strategies, soil application (0.3–10 kg ha−1) and foliar spraying (two rates, different growth stages), were tested in wheat crops under field conditions in the period 2012–2019. A simple soil indicator failed to predict durum wheat response to Zn fertilization. Only one of the combinations tested increased wheat yield in the 11 field experiments carried out. Zinc foliar spraying (1.28 kg ha−1) was effective for wheat biofortification when applied at early booting (durum wheat) or flowering, and also when splitting this application between stem elongation and flowering stages (bread wheat). The foliar treatments produced the highest zinc use efficiencies (6–19%) and soil applications the lowest (0.2–1.3%). Moreover, foliar treatments increased grain Zn concentrations by 12–51% while soil application increased such concentrations by only 4–13%. None of the Zn fertilization strategies altered P uptake. No yield increase in wheat is expected from Zn fertilization for the application methods and rates used here and the soils studied (calcareous Vertisols under Mediterranean climate). However, foliar applications at and after early booting stage are promising for durum and bread wheat biofortification.

The investigation was undertaken with the aim of studying the effect of individual and tank mix applications of zinc sulphate (ZnSO4), ferrous sulphate (FeSO4) and urea on zinc (Zn) and iron (Fe) biofortification of chickpea. A field experiment was conducted in 2015–2016 and 2016–2017 with treatments comprising individual and tank mix applications of ZnSO4 (0.5%), FeSO4 (0.5%) and urea (2%) at flowering and pod formation stages along with control (no nutrient application). Tank mix foliar application of ZnSO4 (0.5%) + FeSO4 (0.5%) + urea (2%) resulted in similar Zn (44.01 and 43.01 mg Zn kg−1 grain in the first and second year of study) and Fe (71.08 and 73.91 mg Fe kg−1 grain) content as in case of individual application of these nutrients (45.08 and 45.00 mg Zn kg−1 and 71.41 and 74.16 mg Fe kg−1 grain) thus showing a positive impact over unsprayed control (25.08 and 25.53 mg Zn kg−1 and 47.58 and 48.66 mg Fe kg−1 grain). Addition of urea (2%) helped in further improvement of Zn and Fe contents over ZnSO4 (0.5%) + FeSO4 (0.5%) spray only. Both tank mix application and individual application of these nutrients recorded significantly higher grain yield and protein content over sole application and control. Tank mix application of ZnSO4 (0.5%), FeSO4 (0.5%) and urea (2%) at flowering and pod formation stages of chickpea is a new method of biofortification which improves Zn and Fe contents and needs a special attention for improving malnutrition in humans.

Zinc (Zn) and phosphorus (P) often interact negatively with each other in soil-plant systems. We investigated the effects of P-Zn interaction on Zn and P accumulation and partitioning in alfalfa. Plants were grown in a calcareous soil supplied with different rates of Zn (0, 200, and 800 mg kg−1) and P (0, 20, and 80 mg kg−1). Plant dry mass, Zn and P concentrations in shoots and roots, bulk soil and rhizosheath pH, rhizosheath carboxylates, and DTPA-extractable Zn concentration in the bulk soil were determined. Phosphorus-Zn interaction significantly affected DTPA-extractable Zn concentration, plant dry mass, accumulation of Zn and P, and partitioning of Zn in alfalfa, but did not affect rhizosheath pH or the amounts of rhizosheath carboxylates. Increasing P rate promoted plant growth at all soil Zn rates and might enhance the plants’ capacity to cope with excessive Zn; it resulted in a lower rhizosheath pH, which likely contributed to greater Zn and P uptake. Zinc deficiency enhanced exudation of citrate, malonate and malate, while the release of tartrate was related with P deficiency. There are strong P-Zn interactions in calcareous soil-plant system, such interactions significantly affect Zn bioavailability, plant growth, accumulation of Zn and P, and partitioning of Zn in alfalfa. Rational P fertilization should be considered for efficient Zn biofortification on Zn-deficient soils and phytoremediation of Zn-contaminated soils.

Soil microbial communities are key players in the development of sustainable food production systems. These soil microbes are responsible for macronutrient and micronutrient mineralization and solubilization in soil. Local effective microorganisms (LEM) are a locally sourced bio-inoculate, made from a fermented mixture of actively decomposing forest litter and a nutrient rich growing media containing carbohydrate, milk, and water. It can be made on farm and have a suite of bacterial communities that includes phototrophic bacteria, phosphorous-solubilizers, ammonia-oxidizers, nitrogen fixers, and actinomycetes. The goal of our research was to (a) investigate microbial diversity in LEM and F-LEM bio-inocula; (b) identify bacterial and archaeal communities in soil after bio-inoculation with LEM, F-LEM, or Control; (c) assess inorganic nitrogen in the soil; and (d) evaluate Ca, Mg, K, and Zn nutrient density in edamame bean (Glycine max) grown with composted broiler litter inoculated with LEM, F-LEM, or Water (Control). Treatments were arranged in a completely randomized block design with four replications on twelve, 18 m2 organically managed plots. Results of microbial characterization indicated greater biodiversity of functional groups in the LEM inoculum. Inorganic N was significantly greater in LEM plots compared to Control in second (2016) and third (2017) years of the study. Biofortification of calcium, magnesium, and zinc density of LEM grown edamame was significantly greater compared to both Control and False-LEM grown edamame (*P

Micronutrient malnutrition or hidden hunger remains a major global challenge for human health and wellness. The problem results from soil micro- and macro-nutrient deficiencies combined with imbalanced fertilizer use. Micronutrient-embedded NPK (MNENPK) complex fertilizers have been developed to overcome the macro- and micro-element deficiencies to enhance the yield and nutritive value of key crop products. We investigated the effect of foliar applications of an MNENPK fertilizer containing N, P, K, Fe, Zn and B in combination with traditional basal NPK fertilizers in terms of eggplant yield, fruit nutritive quality and on soil biological properties. Applying a multi-element foliar fertilizer improved the nutritional quality of eggplant fruit, with a significant increases in the concentration of Fe (+ 26%), Zn (+ 34%), K (+ 6%), Cu (+ 24%), and Mn (+ 27%), all of which are essential for human health. Increasing supply of essential micronutrients during the plant reproductive stages increased fruit yield, as a result of improved yield parameters. The positive effect of foliar fertilizing with MNENPK on soil biological parameters (soil microbial biomass carbon, dehydrogenase, alkaline phosphatase) also demonstrated its capacity to enhance soil fertility. This study suggests that foliar fertilizing with a multi-nutrient product such as MNENPK at eggplant flowering and fruiting stages, combined with the recommended-doses of NPK fertilizers is the optimal strategy to improve the nutritional quality of eggplant fruits and increase crop yields, both of which will contribute to reduce micronutrient malnutrition and hunger globally.

Knowledge of genetic variation, genetics, physiology/molecular basis and breeding (including biotechnological approaches) for biofortification and bioavailability for Zn, Fe and Se will help in developing nutritionally improved wheat. Biofortification of wheat cultivars for micronutrients is a priority research area for wheat geneticists and breeders. It is known that during breeding of wheat cultivars for productivity and quality, a loss of grain micronutrient contents occurred, leading to decline in nutritional quality of wheat grain. Keeping this in view, major efforts have been made during the last two decades for achieving biofortification and bioavailability of wheat grain for micronutrients including Zn, Fe and Se. The studies conducted so far included evaluation of gene pools for contents of not only grain micronutrients as above, but also for phytic acid (PA) or phytate and phytase, so that, while breeding for the micronutrients, bioavailability is also improved. For this purpose, QTL interval mapping and GWAS were carried out to identify QTLs/genes and associated markers that were subsequently used for marker-assisted selection (MAS) during breeding for biofortification. Studies have also been conducted to understand the physiology and molecular basis of biofortification, which also allowed identification of genes for uptake, transport and storage of micronutrients. Transgenics using transgenes have also been produced. The breeding efforts led to the development of at least a dozen cultivars with improved contents of grain micronutrients, although land area occupied by these biofortified cultivars is still marginal. In this review, the available information on different aspects of biofortification and bioavailability of micronutrients including Zn, Fe and Se in wheat has been reviewed for the benefit of those, who plan to start work or already conducting research in this area.

Agronomic biofortification can be used to alleviate the deficient intake of selenium (Se) and zinc (Zn) by livestock. These two essential micronutrients for human and animals play an important role in many physiological functions and biological processes. The aim of the present study was to evaluate the suitability of forage peas, crop with an increasing importance as plant protein source, to be biofortified with a combined treatment of Zn (as ZnSO4-7H2O) and Se (as Na2SeO4). A 2-year field experiment was established in southern Spain under semiarid Mediterranean conditions, by following a split-split-plot design. The study year (2017/2018, 2018/2019) was considered the main-plot factor, soil Zn application (50 kg Zn ha−1, nil Zn) as a subplot factor, and foliar application (nil, 10 g Se ha−1, 8 kg Zn ha−1, 10 g Se ha−1 + 8 kg Zn ha−1) as a sub-subplot factor. The combined application of 50-kg soil Zn ha−1 and the foliar application of 10 g Se ha−1 + 8 kg Zn ha−1 was the most effective treatment to increase the concentration in forage of Zn and Se, 4-fold and 5-fold, respectively, as well as the Zn bioavailability, forage yield (close to 30%), and crude protein (~ 8%). Thus, forage peas could be considered a very suitable crop to be included in biofortification programs under Mediterranean conditions with Zn and Se as target minerals.

Phosphorus is the second most critical macronutrient after nitrogen required for metabolism, growth, and development of plants. Despite the abundance of phosphorus in both organic and inorganic forms in the soil, it is mostly unavailable for plant uptake due to its complexation with metal ions in the soil. The use of agrochemicals to satisfy the demand for phosphorus to improve crop yield has led to the deterioration of the ecosystem and soil health, as well as an imbalance in the soil microbiota. Consequently, there is a demand for an alternate cost-effective and eco-friendly strategy for the biofortification of phosphorus. One such strategy is the application of phosphate-solubilizing microorganisms which can solubilize insoluble phosphates in soil by different mechanisms like secretion of organic acids, enzyme production, and excretion of siderophores that can chelate the metal ions and form complexes, making phosphates available for plant uptake. These microbes not only solubilize phosphates but also promote plant growth and crop yield by producing plant-growth-promoting hormones like auxins, gibberellins, and cytokinins, antibiosis against pathogens, 1-aminocyclopropane-1-carboxylic acid deaminase which enhances plant growth under stress conditions, improving plant resistance to heavy metal toxicity, and so on. Pyrroloquinoline quinine (pqq) and glucose dehydrogenase (gcd) are the representative genes for phosphorus solubilization in microorganisms. The content presented in this review paper focuses on different mechanisms and modes of action of phosphate-solubilizing microorganisms, their contribution to phosphorus solubilization, growth-promoting attributes in plants, and the molecular aspects of phosphorus solubilization.

Agronomic biofortification is a process used to increase the concentration of essential elements in plants through fertilization and thus improve their nutritional quality. Increasing the content of Zn+2 in Stevia rebaudiana plants would imply adding value to the crop. The use of ZnO phytonanoparticles, in addition to increasing the content of Zn+2, can also generate an inductor effect that promotes the synthesis of metabolites of commercial interest. This study reports the effect of fertilization with ZnO phytonanoparticles on morphometric parameters of S. rebaudiana plants and the content of Zn+2, stevioside, rebaudioside A, total phenols, flavonoids and the antiradical activity of leaf extracts. Biofortification was carried out in a hydroponic culture using peat moss/agrolite as a support under a completely random experimental design. The green ZnO nanoparticles were added via root at different concentrations. The physiological and morphometric parameters of the plant were not affected with respect to the control by the use of phytonanoparticles. The biofortification of S. rebaudiana with ZnO phytonanoparticles at a concentration of 75 mg/L enhanced zinc content up to 406.8% with respect to the control. The total phenols (60.5%) and flavonoids (87.8%) were also increased without having a negative effect on plant growth. The biosynthetic pathway of steviol glycosides was not affected.

Iodine deficiency disorders (IDD) in sub-Saharan African countries are related to low dietary I intake and generally combatted through salt iodisation. Agronomic biofortification of food crops may be an alternative approach. This study assessed the effectiveness of I biofortification of green vegetables (Brassica napus L and Amaranthus retroflexus L.) grown in tropical soils with contrasting chemistry and fertility. Application rates of 0, 5 and 10 kg ha−1I applied to foliage or soil were assessed. Leaves were harvested fortnightly for ~ 2 months after I application before a second crop was grown to assess the availability of residual soil I. A separate experiment was used to investigate storage of I within the plants. Iodine concentration and uptake in sequential harvests showed a sharp drop within 28 days of I application in all soil types for all I application levels and methods. This rapid decline likely reflects I fixation in the soil. Iodine biofortification increased I uptake and concentration in the vegetables to a level useful for increasing dietary I intake and could be a feasible way to reduce IDD in tropical regions. However, biofortification of green vegetables which are subject to multiple harvests requires repeated I applications.

Manganese (Mn) deficiency in human nutrition is widespread in the rice–wheat cropping system where cereal grains are the staple food. Agronomic biofortification is an innovative and pragmatic approach to tackle Mn malnutrition. A 2-year field study was conducted to investigate the comparative effect of different Mn application methods: (1) No Mn application, (2) Mn seed coating (2 g kg−1 seed), (3) hydro-priming, (4) Mn seed priming (0.1 M Mn solution), (5) soil application (0.5 kg ha−1), (6) foliar water spray, and (7) foliar Mn spray (0.02 M Mn solution) in improving the productivity, profitability, biofortification and Mn-use efficiencies of rice in puddled transplanted flooded rice (FR) and direct-seeded aerobic rice (AR) production systems. Under AR system, soil physical and biological properties, as well as nutrient dynamics were improved. Averaged across 2 years, improvement in total soil porosity (9%), soil organic carbon (12%), soil microbial biomass carbon (6%), soil microbial biomass nitrogen (3%), total nitrogen (13.6%), available phosphorus (10.98%), and exchangeable potassium (7.1%) were noted in AR system over FR system. Regardless of application methods, Mn nutrition substantially improved the yield and related traits and grain Mn concentration in both production systems. Averaged across 2 years, the increase in grain yield under different Mn application treatments was in the order: foliar application (22%) > seed priming (16%) > soil application (12%) > seed coating (12%). Grain Mn concentration was the highest with foliar application of Mn (27% over control) in both production systems. Moreover, the maximum net benefits and benefit–cost ratio were obtained through Mn-foliar application in both production systems. In conclusion, Mn application by either method improved the productivity, profitability, biofortification and Mn-use efficiencies under FR and AR systems; nevertheless, foliar Mn application performed better for all the studied traits.

Maize is the predominant food source for the world population, but lack of lysine and tryptophan in maize endosperm cannot fulfill the nutritional requirements of humans. Hence, the improvement of lysine and tryptophan content is the ultimate goal of maize biofortification programs. In the present study, the marker-assisted backcross (MABC) breeding strategy was used to enhance the lysine and tryptophan content of the elite maize inbred line UMI1230 by introgressing opaque 2 (o2) gene from the VQL1. During the transfer of the gene into UMI1230, SSR marker umc1066 tightly associated with o2 used for foreground selection. Background recovery was estimated using 168 SSR markers. Phenotype screening for morphological traits was adopted to choose plants parallel to UMI1230. As a result, four BC2F3 improved lines (DBT5-1-14/25-5/25-8/25-8/25, DBT5-1-14/25-5/25-8/25-7/25, DBT5-1-14/25-5/25-8/25-10/25 and DBT5-1-14/25-5/25-8/25-12/25) with o2 were developed. The improved line’s background genome recovery varied between 90.60 and 94.80%. Also, the improved lines had better agronomic performance along with increased lysine (0.311–0.331%) and tryptophan (0.040–0.048%) contents. In summary, the MABC breeding strategy has successfully improved the levels of lysine and tryptophan in UMI1230 without affecting agronomic performance. The improved line’s hold great potential as donors in biofortification programs in maize.

Sweet corn has emerged as a popular vegetable worldwide. Commercial shrunken2 (sh2)-based sweet corn lacks lysine, tryptophan and provitamin-A, deficiency of which cause various health problems. To overcome these problems, marker-assisted stacking of sh2, opaque2 (o2), β-carotene hydroxylase (crtRB1) and lycopene epsilon cyclase (lcyE) was attempted to combine nutritional quality traits in maize endosperm. Gene-based simple sequence marker (SSR) specific to o2, InDel-based marker for crtRB1 and lcyE, and SSR linked to sh2 were used in marker-assisted selection. Four backcross populations segregating for the alleles of crtRB1, lcyE, o2 and sh2 were developed. The favourable alleles of sh2 and o2 produced 103 and 150 bp amplicons, while the unfavourable alleles were 96 and 160 bp, respectively. CrtRB1 produced 543 bp favourable and 296 bp unfavourable allele, while the same for lcyE was 650 and 300 bp, respectively. To detect desirable alleles of the target genes simultaneously, multiplex-PCR (Mx-PCR) assay was developed and validated in BC2F2 populations. Mx-PCR assay successfully identified the favourable alleles of four genes simultaneously, and validated the results of individual uniplex-PCR assays. Mx-PCR assay saved 68% of cost and approximately 63% of time. This is the first report of multiplexing sh2, o2, crtRB1 and lcyE genes in maize. The information generated here would be immensely useful in molecular breeding programme.

Micronutrient deficiency affects billions of people, especially in countries where the diet is low in diversity with inadequate consumption of fruits, vegetables, and animal-source foods, and higher consumption of staple food, i.e., cereals, that have low concentrations of micronutrients. Genetic biofortification is a strategy to mitigate this problem and ensure nutritional security. Wheat is a target of genetic biofortification since it contributes significantly to the caloric requirement. The biofortification process involves a screening related to the presence of genetic variability for grain mineral content. Also, the accumulation of toxic elements must be considered to ensure food safety, because if ingested above the allowed concentrations, it represents health risks. In this sense, this study aimed to quantify the micronutrients iron, zinc, copper, selenium, and manganese and toxic elements arsenic and cadmium in a Brazilian wheat panel grown in Southern Brazil. The presence of genetic variability for the accumulation of micronutrients in the grain was detected; however, we observed that only the copper and manganese accumulation meet the human daily requirements. Iron, zinc, and selenium were detected in insufficient concentration to meet the daily demand. Arsenic and cadmium accumulation were not detected in wheat grain. The wheat genotypes grown in Brazil displayed a similar profile to that found in other countries which may be due to common high-yield breeding goals and the narrowing of the genetic variability, observed worldwide. Thus, the wheat genetic biofortification success in Brazil depends on the introduction of foreign genotypes, landraces, and wild relatives.

Boron (B) is a vital nutrient equally important for plants and human beings. The native soil fertility of arid and semi-arid regions of Pakistan is very low where chickpea is grown on large scale. In such soils, B deficiency is the leading constraint not only for profitable chickpea production but also lead to low B-enriched chickpea grains. Boron seed coating and inoculation with B-tolerant bacteria (BTB) can be effective to improve crop response grown on such soils. Chickpea seeds were coated with different levels of boron (0.0 control; 1.0, 1.5, 2.0, 2.5, and 3.0 g B/kg). Coated and uncoated seeds were divided in two portions and half of these seeds were inoculated with BTB, i.e., Bacillus sp. MN54 while the other half of these seeds were not inoculated with BTB, i.e., Bacillus sp. MN54. Boron seed coating improved seedling growth, nodulation, seed yield, and grain B concentration. Crop response for such characteristics was further augmented with the inoculation of BTB. It was found that seed coating with 1.5 g B kg−1 along with BTB inoculation was the best combination to improve seedling growth, nodulation, and grain yield of chickpea. Higher concentration of B in chickpea seeds was recorded at higher levels of B seed coating (3.0 g B kg−1 soil). Boron seed coating improved grain yield by 9–25% compared with the control treatment. Boron seed coating at lower rates (1.5 g kg−1) along with seed inoculation with BTB Bacillus sp. MN54 seemed a viable option to improve nodulation, growth, yield, and grain B biofortification of chickpea.

Seed priming with distilled water (hydropriming) and with micronutrients (nutripriming) can improve the agronomic performance of various crops. Iron (Fe) and Zinc (Zn) are essential micronutrients for plants and humans that have been widely used in wheat biofortification. However, the micronutrients excess can generate cyto- and phytotoxicity affecting the germination, cell division, development and yield. Seed priming is repeated in each generation, and its effects were never studied in the offspring of primed plants. Whether its advantages, cyto- or phytotoxicity are transmitted to the unprimed offspring are unknown. In this work, we used the first generation of seeds (S1) harvested in plants whose seeds (S0) were hydroprimed and nutriprimed with 4 mg L−1 and/or 8 mg L−1 of Fe and/or Zn. We aimed to study their germination, mitotic cell cycle and seven yield-related components in the adult plants, for further comparison with the data achieved in the S0 generation. A germination percentage of 100% was verified in all S1 offspring. Despite the higher values of the percentage of dividing cells with anomalies (%DCA) in S1 relative to S0, a lower number of types of mitotic irregularities, was found, suggesting cytotoxicity attenuation. The S1 surpassed the S0 for all the yield-related components. Our results suggested that the beneficial effects of hydropriming and Fe and/or Zn nutripriming performed in S0 seeds were enhanced in the S1 offspring via seed provisioning and by the epigenetic inheritance of DNA hypomethylation patterns previously detected in the S0 generation.

Mineral nutrition is one of the key factors determining plant productivity. In plants, metal homeostasis is achieved through the functioning of a complex system governing metal uptake, translocation, distribution, and sequestration, leading to the maintenance of a regulated delivery of micronutrients to metal-requiring processes as well as detoxification of excess or non-essential metals. Low-molecular-weight ligands, such as nicotianamine, histidine, phytochelatins, phytosiderophores, and organic acids, play an important role in metal transport and detoxification in plants. Nicotianamine and histidine are also involved in metal hyperaccumulation, which determines the ability of some plant species to accumulate a large amount of metals in their shoots. In this review we extensively summarize and discuss the current knowledge of the main pathways for the biosynthesis of these ligands, their involvement in metal uptake, radial and long-distance transport, as well as metal influx, isolation and sequestration in plant tissues and cell compartments. It is analyzed how diverse endogenous ligand levels in plants can determine their different tolerance to metal toxic effects. This review focuses on recent advances in understanding the physiological role of these compounds in metal homeostasis, which is an essential task of modern ionomics and plant physiology. It is of key importance in studying the influence of metal deficiency or excess on various physiological processes, which is a prerequisite to the improvement of micronutrient uptake efficiency and crop productivity and to the development of a variety of applications in phytoremediation, phytomining, biofortification, and nutritional crop safety.

There is widespread acknowledgement of the presence of vitamin D deficiency in the community and the pressing need to address this. From a public health perspective, emphasis has been placed on addressing vitamin D deficiency through dietary means. However, naturally rich food sources of vitamin D are few and infrequently consumed, and nutrition survey data from various countries have indicated that habitual vitamin D intakes in the community are much lower than the current vitamin D dietary guidelines. This review will briefly overview the extent of vitamin D deficiency within the community, its causes, and how our food chain, once its embraces the evidence-based practise of food fortification and potentially biofortification, can cater for meeting the dietary vitamin D needs of the community. Finally, international authorities, briefed with establishing vitamin D dietary guidelines over the past decade, have struggled with uncertainties and gaps in our understanding of the relative contribution of sunshine and diet to vitamin D status and vitamin D requirements for health maintenance. The review will also consider how emerging evidence of a possible minimal-risk UVB radiation exposure relative to skin cancer that also enables vitamin D production could greatly inform future vitamin D dietary guidelines.