Biofortification with Selenium: Implications for the Resilience and Nutritional Value of Plants Under Changing Climate Conditions

Selenium (Se) is an essential trace element in animals and humans, usually acquired via nutrition and thus often dependent on the Se content of the soil from where the food crops originate. The uneven distribution of Se in soils may therefore result in regional Se deficiencies, often further exacerbated due to climate change and its subsequent effects on Se speciation (i.e., the chemical forms in which Se occurs) and the element’s mobility. In recent years, biofortification has emerged as a promising approach to address this issue. This review provides an overview of how climate-driven changes in Se cycling influence soil Se availability and discusses the resulting implications for plant resilience, crop biofortification and dietary Se supply. Although plants do not require Se per se, an increased Se content of plants may improve their yields, antioxidant defences, and tolerance to various—climate (change)-related—stresses such as drought, salinity, and oxidative stress at low concentrations. So far, selenite (SeO32−) and selenate (SeO42−) are the most commonly employed Se species in agriculture, often via foliar and soil applications, and due to their excellent solubility in water are subject to leaching or other weather-related limitations. Alternative Se compounds, such as Se nanoparticles (SeNPs) and selenium sulfide (SeS2) present promising approaches that may enable a more controlled Se release in soils. Nonetheless, their long-term agronomic performance and environmental behaviour require further investigations.