Iron-, zinc-, and magnesium-rich field peas (Pisum sativum L.) with naturally low phytic acid: A potential food-based solution to global micronutrient malnutrition

Genome-wide identification, structural characterization and gene expression analysis of the WRKY transcription factor family in pea (Pisum sativum L.)

BACKGROUND

The WRKY gene family is one of the largest families of transcription factors in higher plants, and WRKY transcription factors play important roles in plant growth and development as well as in response to abiotic stresses; however, the WRKY gene family in pea has not been systematically reported.

RESULTS

In this study, 89 pea WRKY genes were identified and named according to the random distribution of PsWRKY genes on seven chromosomes. The gene family was found to have nine pairs of tandem duplicates and 19 pairs of segment duplicates. Phylogenetic analyses of the PsWRKY and 60 Arabidopsis WRKY proteins were performed to determine their homology, and the PsWRKYs were classified into seven subfamilies. Analysis of the physicochemical properties, motif composition, and gene structure of pea WRKYs revealed significant differences in the physicochemical properties within the PsWRKY family; however, their gene structure and protein-conserved motifs were highly conserved among the subfamilies. To further investigate the evolutionary relationships of the PsWRKY family, we constructed comparative syntenic maps of pea with representative monocotyledonous and dicotyledonous plants and found that it was most recently homologous to the dicotyledonous WRKY gene families. Cis-acting element analysis of PsWRKY genes revealed that this gene family can respond to hormones, such as abscisic acid (ABA), indole-3-acetic acid (IAA), gibberellin (GA), methyl jasmonate (MeJA), and salicylic acid (SA). Further analysis of the expression of 14 PsWRKY genes from different subfamilies in different tissues and fruit developmental stages, as well as under five different hormone treatments, revealed differences in their expression patterns in the different tissues and fruit developmental stages, as well as under hormone treatments, suggesting that PsWRKY genes may have different physiological functions and respond to hormones.

CONCLUSIONS

In this study, we systematically identified WRKY genes in pea for the first time and further investigated their physicochemical properties, evolution, and expression patterns, providing a theoretical basis for future studies on the functional characterization of pea WRKY genes during plant growth and development.

Advanced backcross QTL analysis and comparative mapping with RIL QTL studies and GWAS provide an overview of QTL and marker haplotype diversity for resistance to Aphanomyces root rot in pea (Pisum sativum)

Aphanomyces euteiches is the most damaging soilborne pea pathogen in France. Breeding of pea resistant varieties combining a diversity of quantitative trait loci (QTL) is a promising strategy considering previous research achievements in dissecting polygenic resistance to A. euteiches. The objective of this study was to provide an overview of the diversity of QTL and marker haplotypes for resistance to A. euteiches, by integrating a novel QTL mapping study in advanced backcross (AB) populations with previous QTL analyses and genome-wide association study (GWAS) using common markers. QTL analysis was performed in two AB populations derived from the cross between the susceptible spring pea variety "Eden" and the two new sources of partial resistance "E11" and "LISA". The two AB populations were genotyped using 993 and 478 single nucleotide polymorphism (SNP) markers, respectively, and phenotyped for resistance to A. euteiches in controlled conditions and in infested fields at two locations. GWAS and QTL mapping previously reported in the pea-Aphanomyces collection and from four recombinant inbred line (RIL) populations, respectively, were updated using a total of 1,850 additional markers, including the markers used in the Eden x E11 and Eden x LISA populations analysis. A total of 29 resistance-associated SNPs and 171 resistance QTL were identified by GWAS and RIL or AB QTL analyses, respectively, which highlighted 10 consistent genetic regions confirming the previously reported QTL. No new consistent resistance QTL was detected from both Eden x E11 and Eden x LISA AB populations. However, a high diversity of resistance haplotypes was identified at 11 linkage disequilibrium (LD) blocks underlying consistent genetic regions, especially in 14 new sources of resistance from the pea-Aphanomyces collection. An accumulation of favorable haplotypes at these 11 blocks was confirmed in the most resistant pea lines of the collection. This study provides new SNP markers and rare haplotypes associated with the diversity of Aphanomyces root rot resistance QTL investigated, which will be useful for QTL pyramiding strategies to increase resistance levels in future pea varieties.

Combining NDVI and Bacterial Blight Score to Predict Grain Yield in Field Pea

Field pea is the most commonly grown temperate pulse crop, with close to 15 million tons produced globally in 2020. Varieties improved through breeding are important to ensure ongoing improvements in yield and disease resistance. Genomic selection (GS) is a modern breeding approach that could substantially improve the rate of genetic gain for grain yield, and its deployment depends on the prediction accuracy (PA) that can be achieved. In our study, four yield trials representing breeding lines' advancement stages of the breeding program (S0, S1, S2, and S3) were assessed with grain yield, aerial high-throughput phenotyping (normalized difference vegetation index, NDVI), and bacterial blight disease scores (BBSC). Low-to-moderate broad-sense heritability (0.31-0.71) and narrow-sense heritability (0.13-0.71) were observed, as the estimated additive and non-additive genetic components for the three traits varied with the different models fitted. The genetic correlations among the three traits were high, particularly in the S0-S2 stages. NDVI and BBSC were combined to investigate the PA for grain yield by univariate and multivariate GS models, and multivariate models showed higher PA than univariate models in both cross-validation and forward prediction methods. A 6-50% improvement in PA was achieved when multivariate models were deployed. The highest PA was indicated in the forward prediction scenario when the training population consisted of early generation breeding stages with the multivariate models. Both NDVI and BBSC are commonly used traits that could be measured in the early growth stage; however, our study suggested that NDVI is a more useful trait to predict grain yield with high accuracy in the field pea breeding program, especially in diseased trials, through its incorporation into multivariate models.

Organic dry pea (Pisum sativum L.) biofortification for better human health

A primary criticism of organic agriculture is its lower yield and nutritional quality compared to conventional systems. Nutritionally, dry pea (Pisum sativum L.) is a rich source of low digestible carbohydrates, protein, and micronutrients. This study aimed to evaluate dry pea cultivars and advanced breeding lines using on-farm field selections to inform the development of biofortified organic cultivars with increased yield and nutritional quality. A total of 44 dry pea entries were grown in two USDA-certified organic on-farm locations in South Carolina (SC), United States of America (USA) for two years. Seed yield and protein for dry pea ranged from 61 to 3833 kg ha-1 and 12.6 to 34.2 g/100 g, respectively, with low heritability estimates. Total prebiotic carbohydrate concentration ranged from 14.7 to 26.6 g/100 g. A 100-g serving of organic dry pea provides 73.5 to 133% of the recommended daily allowance (%RDA) of prebiotic carbohydrates. Heritability estimates for individual prebiotic carbohydrates ranged from 0.27 to 0.82. Organic dry peas are rich in minerals [iron (Fe): 1.9-26.2 mg/100 g; zinc (Zn): 1.1-7.5 mg/100 g] and have low to moderate concentrations of phytic acid (PA:18.8-516 mg/100 g). The significant cultivar, location, and year effects were evident for grain yield, thousand seed weight (1000-seed weight), and protein, but results for other nutritional traits varied with genotype, environment, and interactions. "AAC Carver," "Jetset," and "Mystique" were the best-adapted cultivars with high yield, and "CDC Striker," "Fiddle," and "Hampton" had the highest protein concentration. These cultivars are the best performing cultivars that should be incorporated into organic dry pea breeding programs to develop cultivars suitable for organic production. In conclusion, organic dry pea has potential as a winter cash crop in southern climates. Still, it will require selecting diverse genetic material and location sourcing to develop improved cultivars with a higher yield, disease resistance, and nutritional quality.

Transient Nutrient Deficiencies in Pea: Consequences on Nutrient Uptake, Remobilization, and Seed Quality

Legume plants, such as peas, are of significant nutritional interest for both humans and animals. However, plant nutrition and thus, seed composition, depends on soil mineral nutrient availability. Understanding the impact of their deprivation on the plant mineral nutrient content, net uptake, and remobilization is of key importance but remains complex as the elements of the plant ionome are linked in intricate networks, one element deprivation impacting uptake and remobilization of other nutrients. To get a better insight into pea mineral nutrition, the transitory deprivations of 13 mineral nutrients were imposed during the vegetative growth phase. Thereafter, plants were grown under optimal mineral conditions until physiological maturity. Plant nutritional status and seed quality impacts caused by the deprivations were characterized using measurement of mineral nutrient concentration and plant biomass allocation. Our results highlight: (i) the preferential allocation of dry weight and elements to shoots at the expense of the roots under non-limiting conditions, and more particularly to the tendrils in comparison to the other shoot organs, (ii) the positive and/or negative impact of one mineral nutrient deprivation on other elements of the ionome, (iii) four different remobilization strategies for eight mineral nutrients, and (iv) possible strategies to improve seed quality via fine control of fertilization during a period of mineral nutrient deficiency.

Isolation and characterization of plant growth promoting rhizobacteria isolated from organically grown high yielding pole type native pea (Pisum sativum L.) variety Dentami of Sikkim, India

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The present research showcases the significant findings pertaining to the assessment and report of the first ever study on the isolation and identification of plant growth promoting rhizobacterial diversity of organic farming pea variety (Dentami) of Sikkim. Proteobacteria dominated the rhizospheric soil whereas the bulk soil was governed by Actinobacteria. Bacillus cereus P8 (66.5 µg ml⁻¹) and Bacillus mycoides PP1 (45.1 µg ml⁻¹) were the highest IAA producer and also showed other plant growth promoting and biocontrol traits, such as phosphorous and potassium solubilization, nitrogen-fixing activity and siderophore production. As, Sikkim is the first state in India to practice organic agriculture farming, hence, such study on the soil microbiology is of immense significance. In these rhizospheric soil, it was dominated by the Proteobacteria and similar bacterial isolates, suggesting that these soil flora might be playing significant roles to enhancing the crop production and soil fertility.

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Culture-dependent technique was used to assess plant growth promoting rhizobacterial diversity of pole type pea variety (Dentami) of Sikkim.

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The dominant phylum was Proteobacteria (56%) from rhizosphere soil and Actinobacteria (58%) from bulk soil.

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PCA analysis showed that Firmicutes (bulk soil) were positively correlated to SOC, and available K, whereas, Proteobacteria (rhizosphere soil) exhibited a high correlation to pH, and available P.

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Bacillus cereus P8, Arthrobacter woluwensis DP2, Paenarthrobacter nitroguajacolicus UP1, and Bacillus mycoides PP1 showed plant growth promotion and bio-control traits.

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Bacillus cereus P8 (66.5 µg mL⁻¹) and Bacillus mycoides PP1 (45.1 µg mL⁻¹) was thehighest IAA producer.

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Pot experiment confirmed that these isolates can be potential plant growth promoter under the agro-climatic conditions of Sikkim, India.

Organic farming is an eco-friendly and sustainable farming practice that enhances soil fertility and helps in improving soil quality. But with the commencement of more sophisticated advances in agricultural techniques, organic farming has gradually become limited in the world. Culture-dependent plant growth-promoting bacterial isolates were isolated from the bulk and rhizospheric soil, of the native high yielding pole type organic pea (Pisum sativum L.) cultivar Dentami of Dentam, West Sikkim, India. Based on the 16S rRNA gene sequencing identification of these isolates, it was found that from the bulk soil, Actinobacteria (58%) was the dominant phyla followed by Firmicutes (28%), and Proteobacteria (14%). In the rhizospheric soil it was dominated by Proteobacteria (56%), followed by Firmicutes (33%), and Bacteriodetes (11%). A total of 40 bacterial isolates were initially screened for the plant growth-promoting (PGP) activity and out of them only four bacterial isolates i.e., Bacillus cereus P8, Arthrobacter woluwensis DP2, Paenarthrobacter nitroguajacolicus PP3, and Bacillus mycoides PP10 with accession numbers MN589697, MN559516, MN519462 and MN589696 respectively were found to possess higher PGP activity (i.e. phosphorous, potassium solubilization and nitrogen-fixing activity) as compared to the other bacteria present in the soil. Based on the indole-3-acetic acid (IAA) quantitative assay and siderophore production assay, it was found that Bacillus cereus (MN589697) produced the highest IAA (65.5 µg mL⁻¹) and siderophore (71%) when compared with the other isolates. The statistical correlation suggests that pH and available phosphorus were the strongest influencing factors for the distribution of Proteobacteria in the rhizospheric soil. The results indicate that these isolates can be potential plant growth promoter under the agro-climatic conditions of Sikkim, India. To the best of our knowledge the present study is the first report of its kind and showcases significant findings pertaining to the assessment of diversity, isolation and identification of plant growth-promoting rhizobacteria of organic pea grown in Sikkim.

Green magnesium oxide nanoparticles-based modulation of cellular oxidative repair mechanisms to reduce arsenic uptake and translocation in rice (Oryza sativa L.) plants

Arsenic (As) accumulation catastrophically disturbs the stability of agricultural systems and human health. Rice easily accumulates a high amount of As from agriculture fields as compare with other cereal crops. Hence, innovative soil remediation methods are needed to deal with the detrimental effects of As on human health causing food security challenges. Here, we report the green synthesis and characterization of magnesium oxide nanoparticles (MgO-NPs) from a native Enterobacter sp. strain RTN2, which was genetically identified through 16S rRNA gene sequence analysis. The biosynthesis of MgO-NPs in reaction mixture was confirmed by UV-vis spectral analysis. X-ray diffraction (XRD) and fourier transform-infrared spectroscopy (FTIR) analysis showed the crystalline nature and surface properties of MgO-NPs, respectively. Moreover, electron microscopy (SEM-EDS, and TEM) imaging confirmed the synthesis of spherical shape of MgO-NPs with variable NPs sizes ranging from 38 to 57 nm. The results revealed that application of MgO-NPs (200 mg kg^-1) in As contaminated soil significantly increased the plant biomass, antioxidant enzymatic contents, and decreased reactive oxygen species and acropetal As translocation as compared with control treatment. The study concluded that biogenic MgO-NPs could be used to formulate a potent nanofertilizer for sustainable rice production in metal contaminated soils.

Genome-wide association studies of mineral and phytic acid concentrations in pea (Pisum sativum L.) to evaluate biofortification potential

Pea (Pisum sativum L.) is an important cool season food legume for sustainable food production and human nutrition due to its nitrogen fixation capabilities and nutrient-dense seed. However, minimal breeding research has been conducted to improve the nutritional quality of the seed for biofortification, and most genomic-assisted breeding studies utilize small populations with few single nucleotide polymorphisms (SNPs). Genomic resources for pea have lagged behind those of other grain crops, but the recent release of the Pea Single Plant Plus Collection (PSPPC) and the pea reference genome provide new tools to study nutritional traits for biofortification. Calcium, phosphorus, potassium, iron, zinc, and phytic acid concentrations were measured in a study population of 299 different accessions grown under greenhouse conditions. Broad phenotypic variation was detected for all parameters except phytic acid. Calcium exhibited moderate broad-sense heritability (H2) estimates, at 50%, while all other minerals exhibited low heritability. Of the accessions used, 267 were previously genotyped in the PSPPC release by the USDA, and we mapped the genotyping data to the pea reference genome for the first time. This study generated 54,344 high-quality SNPs used to investigate the population structure of the PSPPC and perform a genome-wide association study to identify genomic loci associated with mineral concentrations in mature pea seed. Overall, we were able to identify multiple significant SNPs and candidate genes for iron, phosphorus, and zinc. These results can be used for genetic improvement in pea for nutritional traits and biofortification, and the candidate genes provide insight into mineral metabolism.

Biofortification of pea (Pisum sativum L.): a review

Biofortification refers to an approach to increase micronutrient concentrations in the edible parts of plants with increased bioavailability to the human population. Conventional, agronomic and transgenic breeding methods can be used to develop these biofortified crops, offering sustainable and cost-effective strategies. Pea has long been recognized as a valuable, nutritious food for the human diet, but there is a limited amount of information about it, which prevents the full micronutrient enrichment potential of this pulse crop to be reached. Considerations must include not only micronutrient concentrations but also the amount of the nutrient that can be absorbed by the consumer, after processing and cooking. Development of biofortified pea that retains nutrients during cooking and processing is not only essential for fighting micronutrient malnutrition, but also necessary to improve agricultural productivity. © 2021 Society of Chemical Industry.

Combined Selenium and Zinc Biofortification of Bread-Making Wheat under Mediterranean Conditions

Millions of people worldwide have an inadequate intake of selenium (Se) and zinc (Zn), and agronomic biofortification may minimise these problems. To evaluate the efficacy of combined foliar Se and Zn fertilisation in bread making wheat (Triticum aestivum L.), a two-year field experiment was established in southern Spain under semi-arid Mediterranean conditions, by following a split-split-plot design. The study year (2017/2018, 2018/2019) was considered as the main-plot factor, soil Zn application (50 kg Zn ha−1, nor Zn) as a subplot factor and foliar application (nor Se, 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 best treatment to increase both Zn and Se concentration in both straw, 12.3- and 2.7-fold respectively, and grain, 1.3- and 4.3-fold respectively, was the combined foliar application of Zn and Se. This combined Zn and Se application also increased on average the yield of grain, main product of this crop, by almost 7%. Therefore, bread-making wheat seems to be a very suitable crop to be used in biofortification programs with Zn and Se to alleviate their deficiency in both, people when using its grain and livestock when using its straw.

Tempeh: A semicentennial review on its health benefits, fermentation, safety, processing, sustainability, and affordability

Tempeh is a fermented food made of mainly soybeans and is a nutritious, affordable, and sustainable functional source of protein. Globally, tempeh is a widely accepted fermented product. Although there is a growing body of literature on tempeh, most research has focused on unfermented soybeans, thus the impact of tempeh fermentation on biological properties of soybeans has been largely left scattered. The objective of this review is to summarize the literature of tempeh fermentation over the past 60 years. A search of articles on tempeh published from 1960 to 2020 was performed using the Cochrane Library, Web of Science, EBSCOhost FSTA database, and Google Scholar. References from identified articles were reviewed for additional sources. In total, 321 papers were selected for this review, of which 64 papers were related to the health benefits of tempeh. This review concluded that sufficient evidence exists in the literature supporting tempeh fermentation as a low-cost, health-promoting, and sustainable food processing technology to produce protein-rich foods using various beans, legumes, and grains. This comprehensive review suggests further studies are needed on tempeh fermentation and its impact on human health; research and standardization of nonsoy tempeh; assessment of food safety-improving modification in tempeh production system; and initiatives supporting the sourcing of local ingredients in tempeh production.

Perspectives on the genetic improvement of health- and nutrition-related traits in pea

Pea (Pisum sativum L.) is a widely grown pulse crop that is a source of protein, starch and micronutrients in both human diets and livestock feeds. There is currently a strong global focus on making agriculture and food production systems more sustainable, and pea has one of the smallest carbon footprints of all crops. Multiple genetic loci have been identified that influence pea seed protein content, but protein composition is also important nutritionally. Studies have previously identified gene families encoding individual seed protein classes, now documented in a reference pea genome assembly. Much is also known about loci affecting starch metabolism in pea, with research especially focusing on improving concentrations of resistant starch, which has a positive effect on maintaining blood glucose homeostasis. Diversity in natural germplasm for micronutrient concentrations and mineral hyperaccumulation mutants have been discovered, with quantitative trait loci on multiple linkage groups identified for seed micronutrient concentrations. Antinutrients, which affect nutrient bioavailability, must also be considered; mutants in which the concentrations of important antinutrients including phytate and trypsin inhibitors are reduced have already been discovered. Current knowledge on the genetics of nutritional traits in pea will greatly assist with crop improvement for specific end uses, and further identification of genes involved will help advance our knowledge of the control of the synthesis of seed compounds.

Field pea (Pisum sativum L.) shows genetic variation in phosphorus use efficiency in different P environments

Field pea is important to agriculture as a nutritionally dense legume, able to fix nitrogen from the atmosphere and supply it back to the soil. However, field pea requires more phosphorus (P) than other crops. Identifying field pea cultivars with high phosphorus use efficiency (PUE) is highly desirable for organic pulse crop biofortification. This study identified field pea accessions with high PUE by determining (1) the variation in P remobilization rate, (2) correlations between P and phytic acid (PA), and (3) broad-sense heritability estimates of P concentrations. Fifty field pea accessions were grown in a completely randomized design in a greenhouse with two replicates under normal (7551 ppm) and reduced (4459 ppm) P fertilizer conditions and harvested at two time points (mid-pod and full-pod). P concentrations ranged from 332 to 9520 ppm under normal P and from 83 to 8473 ppm under reduced P conditions across all tissues and both time points. Field pea accessions showed variation in remobilization rates, with PI 125840 and PI 137119 increasing remobilization of P under normal P conditions. Field pea accessions PI 411142 and PI 413683 increased P remobilization under the reduced P treatment. No correlation was evident between tissue P concentration and seed PA concentration (8-61 ppm). Finally, seed P concentration under limited P conditions was highly heritable (H2 = 0.85), as was mid-pod lower leaf P concentrations under normal P conditions (H2 = 0.81). In conclusion, breeding for PUE in field pea is possible by selecting for higher P remobilization accessions in low P soils with genetic and location sourcing.

Checking Agriculture's Pulse: Field Pea (Pisum Sativum L.), Sustainability, and Phosphorus Use Efficiency

Investigations regarding the incorporation of better sustainable production strategies into current agricultural-food systems are necessary to grow crops that reduce negative impacts on the environment yet will meet the production and nutritional demand of 10 billion people by 2050. The introduction of organic, alternative staple food crops, such as nutrient-dense field pea (Pisum sativum L.), to the everyday diet, may alleviate micronutrient malnutrition and incorporate more sustainable agriculture practices globally. Varieties are grown in organic systems currently yield less than conventionally produced foods, with less bioavailable nutrients, due to poor soil nutrient content. One of the most limiting nutrients for field pea is phosphorus (P) because this legume crop requires significant inputs for nodule formation. Therefore, P use efficiency (PUE) should be a breeding target for sustainable agriculture and biofortification efforts; the important role of the soil microbiome in nutrient acquisition should also be examined. The objectives of this review are to highlight the benefits of field pea for organic agriculture and human health, and discuss nutritional breeding strategies to increase field pea production in organic systems. Field pea and other pulse crops are underrepresented in agricultural research, yet are important crops for a sustainable future and better food systems. Furthermore, because field pea is consumed globally by both developed and at-risk populations, research efforts could help increase global health overall and combat micronutrient malnutrition.

Improving pulse crops as a source of protein, starch and micronutrients

Pulse crops have been known for a long time to have beneficial nutritional profiles for human diets but have been neglected in terms of cultivation, consumption and scientific research in many parts of the world. Broad dietary shifts will be required if anthropogenic climate change is to be mitigated in the future, and pulse crops should be an important component of this change by providing an environmentally sustainable source of protein, resistant starch and micronutrients. Further enhancement of the nutritional composition of pulse crops could benefit human health, helping to alleviate micronutrient deficiencies and reduce risk of chronic diseases such as type 2 diabetes. This paper reviews current knowledge regarding the nutritional content of pea (Pisum sativum L.) and faba bean (Vicia faba L.), two major UK pulse crops, and discusses the potential for their genetic improvement.

Legume biofortification is an underexploited strategy for combatting hidden hunger

Legumes are the world's primary source of dietary protein and are particularly important for those in developing economies. However, the biofortification potential of legumes remains underexploited. Legumes offer a diversity of micronutrients and amino acids, exceeding or complementing the profiles of cereals. As such, the enhancement of legume nutritional composition presents an appealing target for addressing the "hidden hunger" of global micronutrient malnutrition. Affecting ~2 billion people, micronutrient malnutrition causes severe health effects ranging from stunted growth to reduced lifespan. An increased availability of micronutrient-enriched legumes, particularly to those in socio-economically deprived areas, would serve the dual functions of ameliorating hidden hunger and increasing the positive health effects associated with legumes. Here, we give an updated overview of breeding approaches for the nutritional improvement of legumes, and crucially, we highlight the importance of considering nutritional improvement in a wider ecological context. Specifically, we review the potential of the legume microbiome for agronomic trait improvement and highlight the need for increased genetic, biochemical, and environmental data resources. Finally, we state that such resources should be complemented by an international and multidisciplinary initiative that will drive crop improvement and, most importantly, ensure that research outcomes benefit those who need them most.

Genome-wide SNP identification, linkage map construction and QTL mapping for seed mineral concentrations and contents in pea (Pisum sativum L.)

BACKGROUND

Marker-assisted breeding is now routinely used in major crops to facilitate more efficient cultivar improvement. This has been significantly enabled by the use of next-generation sequencing technology to identify loci and markers associated with traits of interest. While rich in a range of nutritional components, such as protein, mineral nutrients, carbohydrates and several vitamins, pea (Pisum sativum L.), one of the oldest domesticated crops in the world, remains behind many other crops in the availability of genomic and genetic resources. To further improve mineral nutrient levels in pea seeds requires the development of genome-wide tools. The objectives of this research were to develop these tools by: identifying genome-wide single nucleotide polymorphisms (SNPs) using genotyping by sequencing (GBS); constructing a high-density linkage map and comparative maps with other legumes, and identifying quantitative trait loci (QTL) for levels of boron, calcium, iron, potassium, magnesium, manganese, molybdenum, phosphorous, sulfur, and zinc in the seed, as well as for seed weight.

RESULTS

In this study, 1609 high quality SNPs were found to be polymorphic between 'Kiflica' and 'Aragorn', two parents of an F6-derived recombinant inbred line (RIL) population. Mapping 1683 markers including 75 previously published markers and 1608 SNPs developed from the present study generated a linkage map of size 1310.1 cM. Comparative mapping with other legumes demonstrated that the highest level of synteny was observed between pea and the genome of Medicago truncatula. QTL analysis of the RIL population across two locations revealed at least one QTL for each of the mineral nutrient traits. In total, 46 seed mineral concentration QTLs, 37 seed mineral content QTLs, and 6 seed weight QTLs were discovered. The QTLs explained from 2.4% to 43.3% of the phenotypic variance.

CONCLUSION

The genome-wide SNPs and the genetic linkage map developed in this study permitted QTL identification for pea seed mineral nutrients that will serve as important resources to enable marker-assisted selection (MAS) for nutritional quality traits in pea breeding programs.

Soil and foliar zinc biofortification in field pea (Pisum sativum L.): Grain accumulation and bioavailability in raw and cooked grains

To evaluate the potential of cooked field peas to be used in Zn biofortification programs, all combinations of soil Zn application of 0, 4 and 8mgZnSO4·7H2Okg(-1) and foliar Zn application of 0 and two sprays of 0.25% or 0.5% (w/v) ZnSO4·7H2O before flowering and at early grain-filling stage were tested. Soil Zn application increased Zn-DTPA concentration 3.7- to 5.6-times depending on the Zn soil treatments. Grain Zn concentrations higher than 60mgZnkg(-1) were obtained with all foliar Zn applications, alone or in combination with soil Zn applications, and grain Zn bioavailability was adequate (phytate:Zn ratios lower than 15). Processing (freezing and cooking) caused a decrease of about 30% in grain Zn concentration and a 17%-increase in phytate:Zn ratios (to ⩽9.5). The combined application of 8mgZnSO4·7H2Okg(-1) soil+0.25% (w/v) ZnSO4·7H2O foliarly could be a good option for biofortifying field peas.

Optimization of Ultrasound-Assisted Extraction, Preliminary Characterization and In Vitro Antioxidant Activity of Polysaccharides from Green Pea Pods

In this study, ultrasound-assisted extraction of green pea pod polysaccharide (GPPP) was investigated and optimized using a central composite response surface design coupled with a numerical optimization technique. The effects of ultrasonic power (50-150 W), sonication time (20-80 min), ratio of water to raw material (20:1-40:1 mL/g) and extraction temperature (40-80 °C) on polysaccharide extraction yield were studied. The maximum extraction yield was obtained with a sonication power of 135.34 W, extraction time of 48.61 min, ratio of water to raw material of 33.6:1 mL/g and extraction temperature of 68.25 °C. Under these conditions, the experimental yield was 7.37% ± 0.13%, which was in close agreement with the predicted value (7.20%). The GPPP has been analyzed in order to identify a variety of chemical properties. The FT-IR spectrum demonstrated obvious characteristic peaks of polysaccharides. Furthermore, antioxidant activity of GPPP was evaluated by various antioxidant assays in vitro. The results revealed that GPPP possessed considerable DPPH free radical scavenging activity (91.03%), reducing power (0.63) and ferric reducing antioxidant power (0.34 mmol/L) at a total amount of 0.9 mg/mL. These findings indicated that GPPP extracted using an ultrasound-assisted extraction technique has potential as a novel source of natural antioxidant agent for future applications.

Current Knowledge on Genetic Biofortification in Lentil

Micronutrient deficiency in the human body, popularly known as "hidden hunger", causes many health problems. It presently affects >2 billion people worldwide, especially in South Asia and sub-Saharan Africa. Biofortification of food crop varieties is one way to combat the problem of hidden hunger using conventional plant breeding and transgenic methods. Lentils are rich sources of protein, micronutrients, and vitamins including iron, zinc, selenium, folates, and carotenoids. Lentil genetic resources including germplasm and wild species showed genetic variability for these traits. Studies revealed that a single serving of lentils could provide a significant amount of the recommended daily allowance of micronutrients and vitamins for adults. Therefore, lentils have been identified as a food legume for biofortification, which could provide a whole food solution to the global micronutrient malnutrition. The present review discusses the current ongoing efforts toward genetic biofortification in lentils using classical breeding and molecular marker-assisted approaches.

The effects of Mg enrichment of vegetable sprouts on Mg concentration, yield and ROS generation

BACKGROUND

Two-thirds of the world's population do not consume the recommended amount of Mg, hence the demand for the production of Mg-enriched plants. Sprouts represent promising targets for enrichment. This study evaluated the effects of enriching broccoli, radish, alfalfa and mung bean sprouts with Mg (50-300 mg L(-1) ) on (i) the concentration of Mg and other ions, (ii) biomass accumulation, (iii) levels of reactive oxygen species (ROS), and (iv) the activity/content of enzymatic and non-enzymatic components of antioxidative systems.

RESULTS

Enrichment of sprouts with Mg led to a significant increase in Mg concentration, especially in alfalfa (increase of 23-152 %), without depletion of other ions. A higher Mg concentration had a minor effect on biomass accumulation, but increased, often significantly, ROS generation and affected enzymatic and non-enzymatic antioxidative systems. The level of O2 (•-) increased most in broccoli, by 59-158%, while OH(•) increased most in radish, by 200-350%.

CONCLUSIONS

Enrichment of sprouts with Mg is possible, but attention must be paid to elevated ROS levels in food. Mung bean sprouts are best suited to enrichment as they make a considerable contribution to the daily supplementation of Mg, at still low levels of ROS in enriched plants. © 2015 Society of Chemical Industry.

Health benefits of legumes and pulses with a focus on Australian sweet lupins

BACKGROUND AND OBJECTIVES

The 68th United Nations General Assembly declared 2016 the International Year of Pulses. Therefore it is timely to review the current evidence of the benefits of legumes for human health with a focus on Australian sweet lupins.

METHODS AND STUDY DESIGN

Medline, Pubmed, Cochrane library were searched to identify cross-sectional/epidemiological studies, randomised controlled trials (RCTs) and systematic reviews.

RESULTS

The strongest evidence appears to be for links between eating legumes and reduced risk of colorectal cancer as well as eating soy foods and reduced LDL cholesterol. However, epidemiological studies and RCTs suggest that replacing several meat-based meals a week with legumes can have a positive impact on longevity, diabetes, cardiovascular disease and weight management, potentially via favourable effects on the gut microbiome. Sweet lupins are unique among legumes with one of the highest combined amounts of digestible plant protein (38%) and dietary fibre (30%). Unlike other legumes, their low amount of anti-nutritional factors negates the need for soaking/cooking and they can therefore be eaten uncooked. Sweet lupins may lower blood pressure, improve blood lipids and insulin sensitivity and favourably alter the gut microbiome. There is growing interest in pulses, especially sweet lupins, as ingredients to improve the nutritional value of baked goods (particularly gluten free) and to create novel products to replace meat.

CONCLUSION

Legumes form part of most traditional diets. They, including sweet lupins, can play a useful role in health maintenance.

Biofortification of maize with micronutrients by Spirulina

The aim of the present work was to examine the effect of the application of Spirulina platensis post-extraction residues enriched with Zn(II), Mn(II), Cu(II) via biosorption as micronutrient fertilizer for the biofortification of maize grains with micronutrients in field tests. As a nominal dose 2.5 kg ha-1 of zinc, 1.0 kg ha-1 of manganese and 0.5 kg ha-1 of copper were applied. The preparation was applied also in higher doses (150%, 200%) to investigate agronomic biofortification of maize grains.

In field trials, obtained grain yield (7.2 Mg ha-1 for Spirulina 100%) was higher than in control group (6.2 Mg ha-1) and commercial reference product (6.6 Mg ha-1). For the same dose of micronutrients, their bioavailability was higher for bio-preparations than for reference fertilizer. The highest content of micronutrients delivered to plants (2.15 mg kg-1 – Cu, 7.07 mg kg-1 – Mn, 29.0 mg kg-1 – Zn) was observed for maize grains fertilized with preparation of Spirulina 150%, which signifies that biofortified maize grain was obtained. Corn grains biofortified with micronutrients can be used as staple food or feed preventing from micronutrient malnutrition. The application of micronutrient biocomponents based on Spirulina biomass allows to manufacture a valuable fertilizer with bioavailable micronutrients.

The application of biosorption for production of micronutrient fertilizers based on waste biomass

In the present paper, new environmental-friendly fertilizer components were produced in biosorption process by the enrichment of the biomass with zinc, essential in plant cultivation. The obtained new preparations can be used as controlled release micronutrient fertilizers because microelements are bound to the functional groups present in the cell wall structures of the biomass. It is assumed that new fertilizing materials will be characterized by higher bioavailability, gradual release of micronutrients required by plants, and lower leaching to groundwater. The biological origin of the material used in plant fertilization results in the elimination of toxic effect towards plants and groundwater mainly caused by low biodegradability of fertilizers. Utilitarian properties of new formulations enable to reduce negative implications of fertilizers for environmental quality and influence ecological health. In this work, the utilitarian properties of materials such as peat, bark, seaweeds, seaweed post-extraction residues, and spent mushroom substrate enriched via biosorption with Zn(II) ions were examined in germination tests on Lepidium sativum. Obtained results were compared with conventional fertilizers—inorganic salt and chelate. It was shown that zinc fertilization led to biofortification of plant in these micronutrients. Moreover, the mass of plants fertilized with zinc was higher than in the control group.