Biofortification of Six Varieties of Lettuce (Lactuca sativa L.) With Iodine and Selenium in Combination With the Application of Salicylic Acid

Biofortification as a solution for addressing nutrient deficiencies and malnutrition

Malnutrition, defined as both undernutrition and overnutrition, is a major global health concern affecting millions of people. One possible way to address nutrient deficiency and combat malnutrition is through biofortification. A comprehensive review of the literature was conducted to explore the current state of biofortification research, including techniques, applications, effectiveness and challenges. Biofortification is a promising strategy for enhancing the nutritional condition of at-risk populations. Biofortified varieties of basic crops, including rice, wheat, maize and beans, with elevated amounts of vital micronutrients, such as iron, zinc, vitamin A and vitamin C, have been successfully developed using conventional and advanced technologies. Additionally, the ability to specifically modify crop genomes to improve their nutritional profiles has been made possible by recent developments in genetic engineering, such as CRISPR-Cas9 technology. The health conditions of people have been shown to improve and nutrient deficiencies were reduced when biofortified crops were grown. Particularly in environments with limited resources, biofortification showed considerable promise as a long-term and economical solution to nutrient shortages and malnutrition. To fully exploit the potential of biofortified crops to enhance public health and global nutrition, issues such as consumer acceptance, regulatory permitting and production and distribution scaling up need to be resolved. Collaboration among governments, researchers, non-governmental organizations and the private sector is essential to overcome these challenges and promote the widespread adoption of biofortification as a key part of global food security and nutrition strategies.

The Effect of Functionalized Multiwall Carbon Nanotubes with Fe and Mn Oxides on Lactuca sativa L

The aim of this work was to evaluate the effect of six nanomaterials, namely CNT-COOH, CNT-MnO2, CNT-Fe3O4, CNT-MnO2-Fe3O4, MnO2, and Fe3O4 on lettuceTo determine the impact of nanomaterials on lettuce, the results obtained were compared with those for the control plant, grown in the same conditions of light, temperature, and humidity but without the addition of nanomaterial. The study found that the content of bioactive compounds and the antioxidant capacity varied in the treated plants compared to the control ones, depending on the nanomaterial. The use of CNTs functionalized with metal oxides increases the elemental concentration of lettuce leaves for the majority of the elements. On the contrary, metal oxide nanoparticles and CNT functionalized with carboxyl groups induce a decrease in the concentration of many elements. Soil amending with MnO2 affects the content of more than ten elements in leaves. Simultaneous application of CNT and MnO2 stimulates the elemental translocation of all elements from roots to leaves, but the simultaneous use of CNT and Fe3O4 leads to the most intense translocation compared to the control other than Mo.

Current Strategies for Selenium and Iodine Biofortification in Crop Plants

Selenium and iodine are essential trace elements for both humans and animals. Among other things, they have an essential role in thyroid function and the production of important hormones by the thyroid gland. Unfortunately, in many areas, soils are deficient in selenium and iodine, and their amount is insufficient to produce crops with adequate contents to cover the recommended daily intake; thus, deficiencies have an endemic character. With the introduction of iodized table salt in the food industry, the thyroid status of the population has improved, but several areas remain iodine deficient. Furthermore, due to the strong relationship between iodine and selenium in metabolic processes, selenium deficiency often compromises the desired positive impact of salt iodization efforts. Therefore, a considerable number of studies have looked for alternative methods for the simultaneous supplementation of selenium and iodine in foodstuff. In most cases, the subject of these studies is crops; recently, meat has also been a subject of interest. This paper reviews the most recent strategies in agriculture to fortify selenium and iodine in crop plants, their effect on the quality of the plant species used, and the potential impact of food processing on their stability in fortified crops.

Salsola soda as selenium biofortification crop under high saline and boron growing conditions

In California, there is a shortage of good quality water available for irrigated agriculture due to severe drought. Consequently, saline groundwaters and drainage waters containing natural-occurring selenium (Se) and boron (B) salts are being considered as alternative sources of water for irrigation on salt and B tolerant crops like the edible halophyte-agretti (Salsola soda L.). In this multi-year field study, we evaluated agretti grown as a Se-biofortification crop in typical saline/B-laden soils (10 dS m^-1 and 12 mg B/L) and irrigated with saline (3-8 dS m^-1) and low-saline water (<1 d/S m) containing B (3-6 mg B/L) and Se (0.02-0.25 mg Se/L) at different evaporation transpiration (Et _o ) rates (100, 75, and 50 %, respectively). During the four-year study, fresh biomass yields ranged from 1 to 3 kg/m² and were generally highest with irrigation at 100 % Et _o with either saline or low-saline water. Tissue Se concentrations ranged from 2 to 3.2 mg Se / kg DW and 0.4-0.5 mg Se/kg DW with saline and low-saline irrigation, respectively. Selenium speciation in plant tissue showed the following: selenomethionine (SeMet) > selenate (SeO₄) > methylselenocysteine (MeSeCy _s ), irrespective of any treatment (i.e., year of planting, saline or low saline irrigation, rate of water application, direct seeding or transplanted). Agretti did not exhibit any toxicity symptoms as indicated by changes in total phenolic concentrations. Total phenolics ranged from 180 to 257 GAE/L and showed no significant differences among all treatments, although they were generally higher at the lowest water treatment (50% Et _o ). In regard to toxic ion accumulation, agretti tolerated excessive sodium (Na) and boron (B) and tissue concentrations ranging from 5.5 to 8.8% Na and 60 to 235 mg B/kg DW, respectively. Results from this multi-year study have identified a unique Se-biofortification strategy for producing Se-enriched agretti using saline, B- and Se-laden soil and irrigating with saline and low-saline water, respectively. Successful production of this crop may promote Se- biofortification strategies in poor quality regions where natural- occurring Se is present in soils and in waters used for irrigation.

Effects of Individual and Simultaneous Selenium and Iodine Biofortification of Baby-Leaf Lettuce Plants Grown in Two Different Hydroponic Systems

The iodine (I) and selenium (Se) deficiencies affect approximately 30% and 15%, respectively, of the global population. The biofortification of vegetables is a valid way to increase the intake of iodine and selenium through the diet. This study was carried out on baby-leaf lettuce to investigate the effects on plant growth, leaf quality, and leaf I and Se accumulation of adding potassium iodide and sodium selenate, separately and simultaneously, to the nutrient solution in a floating system and aeroponics. The effect of I and Se biofortification on post-harvest quality of lettuce leaves was also evaluated. Our results evidenced that the Se and I treatments increased the content of the two microelements in lettuce leaves without any negative interactions in the plants, when applied either separately or simultaneously. Both hydroponic systems proved to be suitable for producing Se and/or I enriched lettuce. Biofortification with Se was more effective when performed in aeroponics, whereas I biofortification was more effective in the floating system. Quality of leaves during post-harvest storage was not affected by neither of the treatments. Lettuce leaves enriched with 13 µM Se and 5 µMI could be good dietary sources of Se and I without inducing toxic effects in humans.

Joint Biofortification of Plants with Selenium and Iodine: New Field of Discoveries

The essentiality of selenium (Se) and iodine (I) to human beings and the widespread areas of selenium and iodine deficiency determine the high significance of functional food production with high levels of these elements. In this respect, joint biofortification of agricultural crops with Se and I is especially attractive. Nevertheless, in practice this topic has raised many problems connected with the possible utilization of many Se and I chemical forms, different doses and biofortification methods, and the existence of wide species and varietal differences. The limited reports relevant to this subject and the multiplicity of unsolved questions urge the need for an adequate evaluation of the results obtained up-to-date, useful for developing further future investigations. The present review discusses the outcome of joint plant Se-I biofortification, as well as factors affecting Se and I accumulation in plants, paying special attention to unsolved issues. A particular focus has been given to the prospects of herb sprouts production enriched with Se and I, as well as the interactions between the latter microelements and arbuscular-mycorrhizal fungi (AMF).

New Aspects of Uptake and Metabolism of Non-organic and Organic Iodine Compounds-The Role of Vanadium and Plant-Derived Thyroid Hormone Analogs in Lettuce

The process of uptake and translocation of non-organic iodine (I) ions, I^- and IO₃ ^-, has been relatively well-described in literature. The situation is different for low-molecular-weight organic aromatic I compounds, as data on their uptake or metabolic pathway is only fragmentary. The aim of this study was to determine the process of uptake, transport, and metabolism of I applied to lettuce plants by fertigation as KIO₃, KIO₃ + salicylic acid (KIO₃+SA), and iodosalicylates, 5-iodosalicylic acid (5-ISA) and 3,5-diiodosalicylic acid (3,5-diISA), depending on whether additional fertilization with vanadium (V) was used. Each I compound was applied at a dose of 10 μM, SA at a dose of 10 μM, and V at a dose of 0.1 μM. Three independent 2-year-long experiments were carried out with lettuce; two with pot systems using a peat substrate and mineral soil and one with hydroponic lettuce. The effectiveness of I uptake and translocation from the roots to leaves was as follows: 5-ISA > 3,5-diISA > KIO₃. Iodosalicylates, 5-ISA and 3,5-diISA, were naturally synthesized in plants, similarly to other organic iodine metabolites, i.e., iodotyrosine, as well as plant-derived thyroid hormone analogs (PDTHA), triiodothyronine (T3) and thyroxine (T4). T3 and T4 were synthesized in roots with the participation of endogenous and exogenous 5-ISA and 3,5-diISA and then transported to leaves. The level of plant enrichment in I was safe for consumers. Several genes were shown to perform physiological functions, i.e., per64-like, samdmt, msams5, and cipk6.

Biofortification of edible plants with selenium and iodine - A systematic literature review

Soil depletion with absorbed forms of microelements is a realistic problem leading to the formation of many human, plant, animal diseases related with micronutrient deficiencies. Searching for new ways to solve this problem is a crucial for the agro-chemical approach to food production. There are many research papers on plant micronutrient fertilization. However, there is still a lack of systematic review of the literature, which summarizes the most recent knowledge on biofortification of food of plant origin with microelements. This work is a systematic review which presents the various methodologies and compares the results of the applied doses and types of fertilizer formulation with the yield and micronutrient content of edible parts of plants. The PRISMA protocol-based review of the most recent literature data from the last 5 years (2015-2020) concerns enrichment of plants with selenium and iodine. These elements, in contrast to other microelements (zinc, manganese, iron, copper and others) are given to plants most often in anionic form: selenium - SeO₃^2- and SeO₄^2-, iodine - I^- and IO₃^-, making them a separate subgroup of microelements. The review focuses on original research papers (not reviews), collected in 3 popular scientific databases: Scopus, Web of Knowledge, PubMed. This study shows how to effectively cope with hidden hunger taking into account the significance of optimized fertilization. Based on the collected data, the best method of micronutrients administration an integrated fortification strategy for selected trace elements and prospects in research/action development was proposed. It was found that the best way to enrich plants with selenium is foliar fertilization with Se(VI), in increased doses. The effectiveness of fortification is supported by the balanced nutrients fertilization, the presence of microorganisms and selection of plant varieties. Foliar fertilization, in increased doses with iodide (I^-) is in turn an effective way to enrich plants with iodine.

Selenium and Nano-Selenium Biofortification for Human Health: Opportunities and Challenges

Selenium is an essential micronutrient required for the health of humans and lower plants, but its importance for higher plants is still being investigated. The biological functions of Se related to human health revolve around its presence in 25 known selenoproteins (e.g., selenocysteine or the 21st amino acid). Humans may receive their required Se through plant uptake of soil Se, foods enriched in Se, or Se dietary supplements. Selenium nanoparticles (Se-NPs) have been applied to biofortified foods and feeds. Due to low toxicity and high efficiency, Se-NPs are used in applications such as cancer therapy and nano-medicines. Selenium and nano-selenium may be able to support and enhance the productivity of cultivated plants and animals under stressful conditions because they are antimicrobial and anti-carcinogenic agents, with antioxidant capacity and immune-modulatory efficacy. Thus, nano-selenium could be inserted in the feeds of fish and livestock to improvise stress resilience and productivity. This review offers new insights in Se and Se-NPs biofortification for edible plants and farm animals under stressful environments. Further, extensive research on Se-NPs is required to identify possible adverse effects on humans and their cytotoxicity.

Biofortification with selenium and iodine changes morphological properties of Brassica oleracea L. var. gongylodes) and increases their contents in tubers

Kohlrabi (Brassica oleracea L. var. gongylodes L.) was biofortified with selenium (Se), as selenite and selenate, and iodine (I), as iodide and iodate, and their combinations through foliar spraying, to study absorption of these elements by the plants, separately and in combination. The effects on selected physiological and morphological traits and optical characteristics were monitored. Treatments with Se positively affected total chlorophylls and carotenoids, and leaf stomata dimensions. Addition of I decreased total chlorophylls and increased anthocyanins. In reflectance spectra of the leaves, specific colour regions differed significantly due to the different treatments. Reflectance in the UV correlated positively with Se and I contents of the leaves, which indicated lower demand for production of phenolic compounds. Differences in reflectance in UV part of the spectra could be a consequence of changes in the cuticle. The Se and I levels increased markedly in leaves and tubers, without loss of biomass or yield. Se had antagonistic effects on accumulation of I in leaves. The similar levels of Se and I in the leaves and tubers suggest that the transport of both elements in these plants occurs from the leaves to the tubers through the phloem. According to the Se and I contents in the kohlrabi tubers, biofortification with both elements simultaneously is feasible for human nutrition.

Combating Micronutrient Deficiency and Enhancing Food Functional Quality Through Selenium Fortification of Select Lettuce Genotypes Grown in a Closed Soilless System

Selenium (Se) is an essential trace element for human nutrition and a key component of selenoproteins having fundamental biological and nutraceutical functions. We currently examined lettuce biofortification with Se in an open-gas-exchange growth chamber using closed soilless cultivation for delivering Se-rich food. Morphometric traits, minerals, phenolic acids, and carotenoids of two differently pigmented Salanova cultivars were evaluated in response to six Se concentrations (0-40 μM) delivered as sodium selenate in the nutrient solution. All treatments reduced green lettuce fresh yield slightly (9%), while a decrease in red lettuce was observed only at 32 and 40 μM Se (11 and 21% respectively). Leaf Se content increased in both cultivars, with the red accumulating 57% more Se than the green. At 16 μM Se all detected phenolic acids increased, moreover a substantial increase in anthocyanins (184%) was recorded in red Salanova. Selenium applications slightly reduced the carotenoids content of green Salanova, whereas in red Salanova treated with 32 μM Se violaxanthin + neoxanthin, lutein and β-cryptoxanthin spiked by 38.6, 27.4, and 23.1%, respectively. Lettuce constitutes an ideal target crop for selenium biofortification and closed soilless cultivation comprises an effective tool for producing Se-enriched foods of high nutraceutical value.