Selenium Accumulation Research Articles

Effect of Paenibacillus favisporus CHP14 inoculation on selenium accumulation and tolerance of Pakchoi (Brassica chinensis L.) under exogenous selenite treatments

The effects of Paenibacillus favisporus CHP14 inoculation on selenium (Se) accumulation and Se tolerance of Pakchoi were studied by a pot experiment conducted in greenhouse. The results revealed that the growth traits such as plant height, root length, and biomass were significantly elevated during CHP14 treatment at 0 ∼ 8.0 mg·kg−1 Se(IV) levels. CHP14-inoculated plants accumulated more Se in root and shoot, which were 24.1%∼57.3% and 7.5%∼50.9% higher than those of non-inoculated plants. The contents of leaf nitrogen (N), phosphorus (P), magnesium (Mg), and iron (Fe), as well as the ratio of indoleacetic acid and abscisic acid contents (IAA/ABA) were increased by CHP14 inoculation, and positively associated with photosynthetic pigment contents (p < 0.05). At ≥ 4.0 mg·kg−1 Se(IV) levels, superoxide dismutase, peroxidase, and glutathione peroxidase activities of Pakchoi roots were increased with CHP14 inoculation, by 9.9%∼17.1%, 28.4%∼40.7%, and 7.4%∼15.3%, respectively. Moreover, CHP14 inoculation enhanced ascorbate-glutathione (AsA-GSH) metabolism in roots by upregulating the related enzymes activities and antioxidant contents under excess Se(IV) stress. These findings suggest that CHP14 is beneficial to improve plant growth and enhance Se(IV) resistance of Pakchoi, and can be exploited as potential inoculants for phytoremediation process in Se contaminated soil.

Arbuscular Mycorrhizal Fungi Ameliorate Selenium Stress and Increase Antioxidant Potential of Zea mays in Seleniferous Soil.

The indigenous arbuscular mycorrhizal fungi (AMF) spores were isolated from rhizosphere soil associated with maize plants grown in natural selenium-impacted agricultural soils present in north-eastern region of Punjab, India (32°46' N, 74°46' N), with selenium concentration ranging from 2.1 to 6.1 mg kg-1 dry weight, and their role in plant growth promotion, mitigation of selenium stress and phytochemical and antioxidant potential of host maize plants in natural seleniferous soil were examined. Soils with selenium content between 2 and 200 mg kg-1 and producing plants with 45 mg selenium kg-1 dry weight are considered seleniferous soils. AMF inoculum consisting of indigenous AMF spores multiplied in pot cultures were inoculated to maize seeds at the time of sowing alongside control maize seeds in a total of 12 plots (6 replicates) made in seleniferous agricultural fields and sampled at maturity, i.e. 3 months. Asignificant difference was observed in plant growth parameters between control and AMF-inoculated maize plants. AMF-inoculated plants had 24.0 cm and 101.1 cm higher root and shoot length along with 27.2 g, 119.4 g and 28.1 g higher root, shoot and maize cob biomass in comparison to control plants. Se uptake studies through measurement of the emission spectrum of piazselenol complex by fluorescence spectrometry revealed that AMF inoculation led to 6.3 µg g-1 more selenium accumulation in mycorrhizal maize roots in comparison to control roots but lesser translocation to shoots and seeds, i.e. 17.17 µg g-1 and 19.58 µg g-1 lesser. AMF increased total phenolic content by 13 µg GAE mg-1 and total flavonoid content by 13.4 µg QE mg-1 in inoculated maize plants when compared to control plants. Antioxidant studies revealed that AMF inoculation also led to significant rise in enzyme activities by a difference of 115 and 193 EU g-1 in catalase, 140 and 93 EU g-1 in superoxide dismutase, 15 and 37 EU g-1 in ascorbate peroxidase and 19.8 and 23.6% higher DPPH radical scavenging activities, respectively, in shoots and roots of plants with AMF inoculation. The findingsof this study imply that AMF inoculated to maize plants in seleniferous field boost their plant growth and phytochemical and antioxidant properties, as well as minimize Se bioaccumulation in shoots and seeds of plants inoculated with AMF in comparison to control plants.

Enhancement of exercise-induced fatigue alleviation and liver selenium regulation through in situ nanoselenium synthesis by Lactobacillus rhamnosus cells, empowered by Ganoderma lucidum spore loading.

Given the increasing awareness of the negative effects of fatigue on daily activities, mental health, and quality of life, antifatigue supplements are becoming increasingly popular among consumers. Selenium has been found to have antifatigue potential in high dosage, but may cause toxicity effects to the body. In this study, inorganic selenium was first converted to nanoselenium particles via in situ synthesis by Lactobacillus rhamnosus SHA113 (Se-LRS), and then loaded by Ganoderma lucidum spores (GLS). The resulting products were not only assessed for their antioxidant activities, but also the antifatigue potential in mice. As a result, both Se-LRS and the Se-LRS/GLS complex exhibited higher antioxidant and antibacterial activities in simulated gastrointestinal fluids compared to isolated selenium nanoparticles. The Se-LRS/GLS complex demonstrated sustained release of selenium in simulated gastrointestinal fluids and showed significant alleviation of exercise-induced fatigue indicators, but relatively lower liver selenium accumulation in the mice, surpassing the effects of isolated nanoselenium. No toxicity was found to Caco-2 cells for Se-LRS/GLS complex at 2µg/mL. This is a novel approach to enhance the antifatigue potential of selenium without causing extra toxicity.

Transcriptome analysis of high- and low-selenium genotypes identifies genes responsible for selenium absorption, translocation, and accumulation.

Selenium is an essential micronutrient the human body requires, which is closely linked to health. Rice, a primary staple food globally, is a major source of human selenium intake. To develop selenium-enriched rice varieties, it is imperative to understand the mechanisms behind selenium's absorption and transport within rice, alongside identifying the key genes involved in selenium uptake, transport, and transformation within the plant. This study conducted transcriptome sequencing on four types of rice materials (two with low-selenium and two with high-selenium contents) across roots, stems, leaves, and panicles to analyze the gene expression differences. Differential gene expression was observed in the various tissues, identifying 5,815, 6,169, 7,609, and 10,223 distinct genes in roots, stems, leaves, and panicles, respectively. To delve into these differentially expressed genes and identify the hub genes linked to selenium contents, weighted gene co-expression network analysis (WGCNA) was performed. Ultimately, 10, 8, 7, and 6 hub genes in the roots, stems, leaves, and panicles, respectively, were identified. The identification of these hub genes substantially aids in advancing our understanding of the molecular mechanisms involved in selenium absorption and transport during the growth of rice.

Identification, characterization, and expression analysis of WRKY transcription factors in Cardamine violifolia reveal the key genes involved in regulating selenium accumulation

BackgroundCardamine violifolia is a significant Brassicaceae plant known for its high selenium (Se) accumulation capacity, serving as an essential source of Se for both humans and animals. WRKY transcription factors play crucial roles in plant responses to various biotic and abiotic stresses, including cadmium stress, iron deficiency, and Se tolerance. However, the molecular mechanism of CvWRKY in Se accumulation is not completely clear.ResultsIn this study, 120 WRKYs with conserved domains were identified from C. violifolia and classified into three groups based on phylogenetic relationships, with Group II further subdivided into five subgroups. Gene structure analysis revealed WRKY variations and mutations within the CvWRKYs. Segmental duplication events were identified as the primary driving force behind the expansion of the CvWRKY family, with numerous stress-responsive cis-acting elements found in the promoters of CvWRKYs. Transcriptome analysis of plants treated with exogenous Se and determination of Se levels revealed a strong positive correlation between the expression levels of CvWRKY034 and the Se content. Moreover, CvWRKY021 and CvWRKY099 exhibited high homology with AtWRKY47, a gene involved in regulating Se accumulation in Arabidopsis thaliana. The WRKY domains of CvWRKY021 and AtWRKY47 were highly conserved, and transcriptome data analysis revealed that CvWRKY021 responded to Na2SeO4 induction, showing a positive correlation with the concentration of Na2SeO4 treatment. Under the induction of Na2SeO3, CvWRKY021 and CvWRKY034 were significantly upregulated in the roots but downregulated in the shoots, and the Se content in the roots increased significantly and was mainly concentrated in the roots. CvWRKY021 and CvWRKY034 may be involved in the accumulation of Se in roots.ConclusionsThe results of this study elucidate the evolution of CvWRKYs in the C. violifolia genome and provide valuable resources for further understanding the functional characteristics of WRKYs related to Se hyperaccumulation in C. violifolia.

Combinatorial accumulation, stress response, detoxification and synaptic transmission effects of cadmium and selenium in clams Ruditapes philippinarum

This study investigated the toxicological effects and mechanisms of cadmium (Cd) (5 and 50 μg/L) and selenium (Se) (3 and 30 μg/L) at environmentally relevant concentrations on the gills and digestive glands of clams Ruditapes philippinarum. Results indicated that Cd and Se could tissue-specifically impact osmoregulation, energy metabolism, and synaptic transmission in the gills and digestive glands of clams. After exposure to 50 μg/L Cd, the digestive glands of clams up-regulated the expression of methionine-gamma-lyase and metallothionein for detoxification. Clam digestive glands exposed to 3 μg/L Se up-regulated the expression of catalase and glutathione peroxidase to alleviate oxidative stress, and down-regulated the expression of selenide-water dikinase to reduce the conversion of inorganic Se. Additionally, the interaction mode between Cd and Se largely depended on their molar ratio, with a ratio of 11.71 (50 μg/L Cd + 3 μg/L Se) demonstrated to be particularly harmful, as manifested by significantly more lesions, oxidative stress, and detoxification demand in clams than those exposed to Cd or Se alone. Collectively, this study revealed the complex interaction patterns and mechanisms of Cd and Se on clams, providing a reference for exploring their single and combined toxicity.

Integrated analysis of transcriptome, proteome and non-targeted metabolome for exploring the mechanism of selenium biotransformation in Pichia kudriavzevii

Pichia kudriavzevii could resist high concentrations of sodium selenite and efficiently biotransform over 80% of the absorbed selenium. However, the specific molecular mechanisms underlying this biotransformation remain unclear. This study aimed to investigate the mechanism of selenium biotransformation focusing on selenium transport, detoxification, reduction, and the formation of organic selenium compounds through a comprehensive approach combining transcriptomic, proteomic, and non-targeted metabolomic analyze. Results showed that the JEN1 gene was responsible for selenium transport, while the upregulation of cysJ, CYSK, TRXB1 and sat genes as well as the involvement of glutathione, are crucial for the accumulation of organic selenium. Furthermore, GSTY2, TRXB1 and GPX3 were pivotal genes in Se(IV) reduction and their corresponding proteins were key proteins. Additionally, the enhanced expression of genes related to antioxidant enzymes (GSTY2, TRXB1, and GPX3), ABC transports, heat shock proteins and antioxidant enzymes proteins (GSTY2, TRXB1, and GPX3) collectively contributed to selenium tolerance, detoxification and protection against oxidative damage. GO and KEGG analysis highlighted alterations in amino acid metabolism, carbohydrate metabolism, and energy metabolism in the selenium biotransformation process. These findings provide novel insight into the mechanisms of selenium biotransformation in P. kudriavzevii and its application in the fields of the food industry.

Prevotella copri Improves Selenium Deposition and Meat Quality in the longissimus dorsi Muscle of Fattening Pigs.

Selenium is among the important trace elements that influence the quality of meat. Although it has been established that the gut microbiota is closely associated with selenium metabolism, it has yet to be determined whether these microbes influence the accumulation of selenium in muscles. To identify gut microbiota that potentially influence the deposition of selenium in muscles, we compared the colonic microbial composition of pigs characterized by high and low contents of selenium in the longissimus dorsi muscle and accordingly detected a higher abundance of the bacterium Prevotella copri (P. copri) in pigs with a higher muscle selenium content. To verify the effect of P. copri, 16 pigs weighing approximately 61kg were fed either a basal diet or a basal diet supplemented with P. copri (1.0 × 1010CFU/kg feed) for 45days. The results revealed significant increases in the contents of selenium and selenoprotein in the serum and longissimus dorsi muscle of fattening pigs fed the P. copri-supplemented diet. Moreover, supplementing the feed of pigs with P. copri was observed to promote significant improvement in the antioxidant capacity and quality of meat, including drip loss, pH, and meat color. In conclusion, our findings in this study indicate that P. copri has potential utility as a dietary supplement for improving the selenium status and meat quality in fattening pigs.

Accumulation and metabolism of selenium in the rare yeast Kazachstania unispora during the selenium enrichment process

Selenium (Se)-enriched yeast is a good nutritional source for human being. Kazachstania unispora (K. unispora) has shown the positive physiological functionality for human health, whose potential for Se enrichment, however, remains elusive. This study demonstrated the ability of K. unispora to convert inorganic Se to organic Se, and then comprehensively investigated the accumulation and metabolism of Se in K. unispora. The results indicated that K. unispora can effectively accumulate organic Se, of which 95% of absorbed Se was converted to organic forms. Among these organic Se, 46.17% of them was bound to protein and 16.78% was combined with polysaccharides. In addition, some of the organic Se was metabolized to selenomethionine (30.26%) and selenocystine (3.02%), during which four low-molecular weight selenometabolites were identified in K. unispora. These findings expand the scope of Se-enriched yeast species, and provide useful knowledge for further investigation of Se enrichment mechanism in K. unispora.

Overexpression of Wheat Selenium-Binding Protein Gene TaSBP-A Enhances Plant Growth and Grain Selenium Accumulation under Spraying Sodium Selenite.

Selenium (Se) is an essential trace element for humans. Low concentrations of Se can promote plant growth and development. Enhancing grain yield and crop Se content is significant, as major food crops generally have low Se content. Studies have shown that Se biofortification can significantly increase Se content in plant tissues. In this study, the genetic transformation of wheat was conducted to evaluate the agronomic traits of non-transgenic control and transgenic wheat before and after Se application. Se content, speciation, and transfer coefficients in wheat grains were detected. Molecular docking simulations and transcriptome data were utilized to explore the effects of selenium-binding protein-A TaSBP-A on wheat growth and grain Se accumulation and transport. The results showed that TaSBP-A gene overexpression significantly increased plant height (by 18.50%), number of spikelets (by 11.74%), and number of grains in a spike (by 35.66%) in wheat. Under normal growth conditions, Se content in transgenic wheat grains did not change significantly, but after applying sodium selenite, Se content in transgenic wheat grains significantly increased. Analysis of Se speciation revealed that organic forms of selenomethionine (SeMet) and selenocysteine (SeCys) predominated in both W48 and transgenic wheat grains. Moreover, TaSBP-A significantly increased the transfer coefficients of Se from solution to roots and from flag leaves to grains. Additionally, it was found that with the increase in TaSBP-A gene overexpression levels in transgenic wheat, the transfer coefficient of Se from flag leaves to grains also increased.

Inoculation with Funneliformis mosseae promotes selenium accumulation and transformation in pepper (Capsicum annuum L.)

Selenium (Se) is one of the fifteen essential nutrients required by the human body. Mycorrhizal microorganisms play a crucial role in enhancing selenium availability in plants. However, limited research exists on the impact of arbuscular mycorrhizal fungi (AMF) on selenium accumulation and transport in pepper plants. This study employed a pot experiment to investigate the changes in pepper plant growth, selenium accumulation, and transformation following inoculation with AMF and varying concentrations of exogenous selenium. The results indicate that exogenous selenium application in pepper has dual effects. At low concentrations (≤8 mg L⁻1), it promotes growth and nutrient accumulation, whereas high concentrations (>16 mg L⁻1) inhibit these processes. AMF inoculation positively influences selenium accumulation and transport in peppers, significantly increasing yield per plant by 17.89%, vitamin C content by 67.36%, flavonoid content by 43.26%, capsaicin content by 14.82%, DPPH radical scavenging rate by 18.18%, and ABTS radical scavenging rate by 27.81%. Additionally, it significantly reduces selenocysteine methyltransferase (SMT) enzyme activity, while minimally affecting ATP sulfurylase (ATPS) and adenosyl sulfate reductase (APR) enzyme activities. The combined treatment of AMF and 8 mg L⁻1 exogenous selenium has been proven to be the most effective for selenium enrichment in peppers, offering new insights into utilizing exogenous selenium and AMF inoculation to enhance selenium content in peppers.

Effects of different rootstocks grafting on selenium accumulation in Cyphomandra betacea Sendt. seedlings under selenium-contaminated soil

The effects of rootstocks tomato (Solanum lycopersicum L.), eggplant (Solanum melongena L.), and nightshade (Solanum nigrum L.) grafting on the growth and selenium (Se) accumulation of Cyphomandra betacea Sendt. seedlings were studied to identify the most suitable rootstock for increasing Se uptake of fruit trees grown in Se-contaminated soil. The rootstocks of tomato, eggplant, and nightshade grafting increased the scion biomass of C. betacea seedlings by 146.1%, 23.2%, and 94.5%, respectively, compared with the un-grafted seedlings. Moreover, tomato, eggplant, and nightshade rootstocks grafting increased the photosynthesis, superoxide dismutase activity, and peroxidase activity, while reducing the catalase activity and soluble protein content of C. betacea seedlings. Although all three rootstocks grafting decreased Se contents in rootstock roots and stems, only nightshade rootstock grafting increased Se content in the scions of C. betacea seedlings. Notably, root biomass, catalase activity, soluble protein content, rootstock root Se content, and rootstock stem Se content were closely related to the scion Se content. These findings suggest that only grafting onto nightshade rootstock significantly enhances Se uptake in C. betacea, whereas tomato and eggplant rootstocks grafting have no effect on Se uptake.

Selenium enhancement strategy under precise fertilization in foxtail millet rhizosphere

Enhancing selenium content in millet is a crucial strategy to address malnutrition due to selenium deficiency. Jingu 21 was used as the experimental material in this study. The effects of selenium fertilizer application amount, vertical position of fertilization, and horizontal position of fertilization on the selenium content in various millet organs were assessed using a three-factor, five-level quadratic rotation combination design. The results indicate that selenium fertilizer application amount, vertical fertilization position, and horizontal fertilization position significantly affected the selenium content in various millet organs. Analysis of the selenium accumulation for different millet organs show that the recommended optimal agronomic strategy for producing selenium-enriched millet comprises a selenium fertilizer application amount ranging from 100.65 to 120.15 kg/hm2, a vertical fertilization position of 10.28–11.76 cm, and a horizontal fertilization position of 6.74–7.29 cm. This study elucidates the patterns of selenium content accumulation under precise fertilization measures of millet and provides valuable insights for implementing selenium enhancement techniques in the production of selenium-enriched millet.

Enhancing Selenium Accumulation in Rhodotorula mucilaginosa Strain 6S Using a Proteomic Approach for Aquafeed Development.

It is known that selenium (Se) is an essential trace element, important for the growth and other biological functions of fish. One of its most important functions is to contribute to the preservation of certain biological components, such as DNA, proteins, and lipids, providing protection against free radicals resulting from normal metabolism. The objective of this study was to evaluate and optimize selenium accumulation in the native yeast Rhodotorula mucilaginosa 6S. Sodium selenite was evaluated at different concentrations (5-10-15-20-30-40 mg/L). Similarly, the effects of different concentrations of nitrogen sources and pH on cell growth and selenium accumulation in the yeast were analyzed. Subsequently, the best cultivation conditions were scaled up to a 2 L reactor with constant aeration, and the proteome of the yeast cultured with and without sodium selenite was evaluated. The optimal conditions for biomass generation and selenium accumulation were found with ammonium chloride and pH 5.5. Incorporating sodium selenite (30 mg/L) during the exponential phase in the bioreactor after 72 h of cultivation resulted in 10 g/L of biomass, with 0.25 mg total Se/g biomass, composed of 25% proteins, 15% lipids, and 0.850 mg total carotenoids/g biomass. The analysis of the proteomes associated with yeast cultivation with and without selenium revealed a total of 1871 proteins. The results obtained showed that the dynamic changes in the proteome, in response to selenium in the experimental medium, are directly related to catalytic activity and oxidoreductase activity in the yeast. R. mucilaginosa 6S could be an alternative for the generation of selenium-rich biomass with a composition of other nutritional compounds also of interest in aquaculture, such as proteins, lipids, and pigments.

Mercury and Selenium Accumulation in the Tissues of Stranded Bottlenose Dolphins (Tursiops truncatus) in Northeast Florida, 2013-2021.

Bottlenose dolphins (Tursiops truncatus) are long-lived marine mammals, upper-level predators, and they inhabit near-shore environments, which increases their exposure to pollution. Mercury is a ubiquitous and persistent metal pollutant that can bioaccumulate and biomagnify up the food chain. Dolphins are known to accumulate mercury, and limited research has shown that mercury exposure can weaken the immune system of dolphins. The objectives of this study were to assess the mercury concentrations in the tissues (muscle, small intestine, liver) of stranded bottlenose dolphins and to compare the tissue mercury levels in dolphins that were stranded during the 2013-2015 morbillivirus Unusual Mortality Event (UME; immunosuppressed individuals) with the levels of those that were stranded at a normal rate (2016-2021). Selenium has been shown to reduce mercury toxicity in many animals; therefore, tissue selenium concentration and the molar ratio of selenium to mercury were also assessed. The tissue mercury (muscle, liver) and selenium (liver) concentrations increased with the age of the dolphins, with the liver accumulating the highest concentrations. No sex differences were observed in the mercury and selenium concentrations. While differences in tissue mercury concentrations were not observed due to the UME, the selenium accumulation profiles were significantly different between the two time periods. These results suggest that selenium may not have been as protective against mercury toxicity in the bottlenose dolphins that were stranded during the UME, possibly due to infection with morbillivirus.

The relationship between cellular protein content and selenium accumulation in freshwater microalgae.

Variability in the bioconcentration of selenium (Se) by primary producers at the base of the food web results in uncertainty in predictions of bioaccumulation and ecological risk to higher trophic level organisms. Water chemistry, speciation of Se, and periphyton community composition have all been suggested as factors that contribute to variability in bioconcentration by primary producers; however, the role of physiological composition of periphyton species in influencing the bioconcentration of Se has not been previously evaluated. To determine if a relationship exists between algal protein content and Se accumulation, Parachlorella kessleri, Chlorella vulgaris, and Raphidocelis subcapitata were exposed to Se (as selenate) and analyzed for total protein and tissue Se content in the exponential and stationary growth phases. Protein content and Se accumulation in R. subcapitata in the stationary phase were also measured under two light intensities. No relationship between cellular protein content and Se accumulation was found for algae in the exponential phase; however, a strong relationship was found in the stationary phase among species and for R. subcapitata under differing light intensities. Absolute Se accumulations by P. kessleri, C. vulgaris, and R. subcapitata in the stationary phase were statistically different; however, the concentrations of Se in protein were similar across species. These results suggest that cellular protein content in microalgae influences Se bioconcentration and that algal protein content may improve Se bioaccumulation modeling in food webs. Integr Environ Assess Manag 2024;00:1-10. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Exogenous indole-3-acetic acid promotes the plant growth and accumulation of selenium in grapevine under selenium stress

To alleviate the selenium (Se) stress in fruit trees and improve its accumulation, the effects of exogenous indole-3-acetic acid (IAA) on the growth and Se accumulation of grapevine under Se stress were studied. The application of exogenous IAA increased the biomass of grapevine, and the concentration of exogenous IAA had a regression relationship with the biomass. The root and shoot biomass were the maximum at 60 mg L− 1 IAA, increasing by 15.61% and 23.95%, respectively, compared with the control. Exogenous IAA also increased the photosynthetic pigments and the activities of superoxide dismutase and peroxidase in grapevine. Moreover, exogenous IAA increased the contents of total Se, organic Se, and inorganic Se, and the concentration of exogenous IAA had a regression relationship with the total Se content. The highest contents of root total Se and shoot total Se were accumulated at 90 mg L− 1 IAA, increasing by 29.94% and 55.77% respectively,. In addition, the correlation and path analyses revealed that the carotenoid content and root total Se content were closely associated with the shoot total Se content. Therefore, the application of exogenous IAA can alleviate the stress of Se to grape and promote its uptake and the most effective amount for the uptake of Se is 90 mg L− 1 IAA.

Identification and functional characterization of ABC transporters for selenium accumulation and tolerance in soybean

ATP-binding cassette (ABC) transporters were crucial for various physiological processes like nutrition, development, and environmental interactions. Selenium (Se) is an essential micronutrient for humans, and its role in plants depends on applied dosage. ABC transporters are considered to participate in Se translocation in plants, but detailed studies in soybean are still lacking. We identified 196 ABC genes in soybean transcriptome under Se exposure using next-generation sequencing and single-molecule real-time sequencing technology. These proteins fell into eight subfamilies: 8 GmABCA, 51 GmABCB, 39 GmABCC, 5 GmABCD, 1 GmABCE, 10 GmABCF, 74 GmABCG, and 8 GmABCI, with amino acid length 121–3022 aa, molecular weight 13.50–341.04 kDa, and isoelectric point 4.06–9.82. We predicted a total of 15 motifs, some of which were specific to certain subfamilies (especially GmABCB, GmABCC, and GmABCG). We also found predicted alternative splicing in GmABCs: 60 events in selenium nanoparticles (SeNPs)-treated, 37 in sodium selenite (Na2SeO3)-treated samples. The GmABC genes showed differential expression in leaves and roots under different application of Se species and Se levels, most of which are belonged to GmABCB, GmABCC, and GmABCG subfamilies with functions in auxin transport, barrier formation, and detoxification. Protein-protein interaction and weighted gene co-expression network analysis suggested functional gene networks with hub ABC genes, contributing to our understanding of their biological functions. Our results illuminate the contributions of GmABC genes to Se accumulation and tolerance in soybean and provide insight for a better understanding of their roles in soybean as well as in other plants.

Generation of selenium-rich wheat mutants and exploration of responsive genes for selenium accumulation.

Salt tolerance, selenium accumulation and expression of the responsive genes were analyzed in the wheat high selenium mutants. Selenium is an essential trace element for the human body, and its deficiency can lead to various diseases such as Keshan disease and large bone disease. Wheat, being a major staple crop, plays a crucial role in providing dietary selenium supplementation to combat this deficiency. Despite progress in understanding the molecular regulation of selenium accumulation in certain crops, the molecular mechanisms governing selenium accumulation-related gene expression in wheat plants remain poorly understood. In this study, three mutant wheat lines with elevated selenium content were identified. Under the treatment of Na2SeO3 or NaCl, the selenium-rich wheat mutants exhibited decreased sensitivity to both selenium and NaCl compared to the wild type. Additionally, there was an increase in the activities of SOD and POD, while the content of MDA decreased. Through qRT-PCR analysis, the expression of selenium-related genes was affected, revealing that some of these genes not only regulate the response of wheat to salt stress, but also play a role in the process of selenium accumulation. The transcriptome results revealed that the important genes encoding glutathione S-transferases, peroxidases, superoxide dismutases, and UDP-glucosyltransferases may function in the regulation of salt tolerance and selenium accumulation in wheat. These findings significantly contribute to the current understanding of the molecular regulation of selenium accumulation in wheat crops, while also offering novel germplasm resources for cultivating selenium-rich and salt-tolerant wheat lines.

Microalgae enriched in selenium as a good source of micronutrients

Recently, the market for plant-based products has been growing rapidly growing due to the increasing popularity of so-called "novel foods". Many people choose to incorporate plant-based products into their diets because of the potential health benefits. Innovative food sources are also being sought to supply the body with essential nutrients. Microalgae, including Arthrospira platensis or Chlorella vulgaris, are examples of plant products that are valuable sources of proteins, vitamins, and minerals. Enriching commercially available microalgae with elements essential for humans may be the answer to addressing the deficiency of many elements in the diets of people worldwide.One of the elements whose deficiency in the diet is widely described in the literature is selenium. Therefore, the main objective of this work is the study of the identification of certain small molecular selenium-containing compounds in microalgae cultured on a selenium-enriched medium. High-performance liquid chromatography coupled with tandem mass spectrometry with inductively coupled plasma ionization (HPLC-ICP-MS/MS) and electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) were used as analytical techniques.The main conclusion and novelty of the research carried out was the confirmation of the possibility of selenium accumulation by microalgae and the presence of inorganic forms and the expected certain small organic forms, the bioavailability of which is beneficial for humans. The use of HPLC-ESI-MS/MS allowed for the identification of selenium compounds present in the studied microalgae - selenomethionine, selenohomolantionine, selenoadenosine and Se-adenosyl-L-homocysteine.