Selenium biofortification in field-grown tomatoes as affected by Stanleya pinnata-derived organic Se application, biochar and irrigation

Authors: Banuelos, Gary; CENTOFANTI, TIZIANA - Central European University; ZAMBRANO, MARIA - California State University; Arroyo, Irvin; Wang, Dong

Submitted to: Journal of Agriculture and Food Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2025
Publication Date: 7/8/2025
Citation: Banuelos, G.S., Centofanti, T., Zambrano, M.C., Arroyo, I.S., Wang, D. 2025. Selenium biofortification in field-grown tomatoes as affected by Stanleya pinnata-derived organic Se application, biochar and irrigation. Journal of Agriculture and Food Research. 23. Article 102162. https://doi.org/10.1016/j.jafr.2025.102162.
DOI: https://doi.org/10.1016/j.jafr.2025.102162

Interpretive Summary: Selenium (Se) biofortification is a plant-based strategy to increase Se content in edible crops by adding inorganic or organic Se to the soil or to the crop. The subsequent production and consumption of Se-enriched crops can increase Se intake for people worldwide experiencing mild to moderate Se deficiencies in low Se containing regions. In this 2-year biofortification study, Se accumulation was evaluated in field-grown tomatoes after the soil addition of organic Se as Se-enriched plant material in year 1, and after the soil addition of extractable organic Se from plant material in year 2. In addition, the soil was amended prior to study with or without biochar and irrigated with three different rates of water application for each respective year. Results showed that the combination of biochar and deficit irrigation reduced tomato fruit fresh weight but had no effect on the accumulation of Se in the fruit. However, Se concentrations increased in tomato fruit grown with both the soil application of Se-enriched plant tissue and with the soil application of extractable Se from plant tissue, irrespective of biochar and irrigation treatment. Selenium speciation of the tomato fruit showed high concentrations of beneficial organic Se species. In conclusion, biochar did not significantly contribute to Se biofortification. The soil application of Se-enriched plant material with 100% irrigation without biochar was the most effective biofortification treatment for increasing total Se and organic Se contents in tomato fruits grown in a light textured soil.

Technical Abstract: Reportedly, more than one billion of the world’s population suffers from some degree of Se-deficiency in many regions of the world. Selenium an essential micronutrient and is involved in the immune system, regulation of the thyroid gland, and can function as an antioxidant in a detoxification capacity. Plant food products are a primary dietary source of Se for humans; however, many crops are generally low in Se not only because they are grown in soils low in Se because Se uptake and its accumulation varies among plant species. To promote intake, an agricultural strategy called “Se biofortification” has been developed for increasing the Se concentration in the edible parts of the crop or crop products. In this two-year field study, we evaluated Se biofortification and Se speciation of Se in the fruit of tomato plants (Solanum Lycopersicon) grown in light-textured soils amended with and without biochar, exposed to water treatments (50,75 and 100% Eto) and received organic Se treatments from soil applied Se-enriched (350 mg Se kg-1 DW) Prince Plum (S. pinnata) at three rates (100, 200, and 400 g ha-1) in year 1 and received extractable Se from S. pinnata at rates of 50 and 100 g ha-1 in year 2. Results showed that the combination of biochar and deficit irrigation at 50% ETo, significantly reduced tomato fruit fresh weight compared to other treatments. Selenium concentrations were as high as 0.40 mg Se/kg DW in tomato fruit grown with soil application of S. pinnata in year 1 and 0.15 mg Se/kg DW with soil application of extractable Se from S. pinnata, irrespective of addition of biochar or water treatment. Selenium speciation of the tomato fruit showed that selenomethionine (SeMet) and gamma-glutamyl-Se-selenomethyl-selenocysteine ('-glu-MeSeCys) were the two major seleno-amino acids significantly detected at the highest levels in the tomato fruit, followed by SeCys2, selenite, selenate, irrespective of treatments. In conclusion, biochar did not play a significant role in Se biofortification tin tomatoes. Soil application of S. pinnata at rate of 400 g ha-1 at 100% ETo, without biochar was the most effective treatment for increasing Se content and '-glu-MeSeCys composition in tomato fruits grown in a light textured soil.