Enhancing selenium biofortification: strategies for improving soil-to-plant transfer

Selenium (Se) is one of the essential trace elements for humans. Plants are the main source of Se for humans, while soil Se is the primary source of Se for plants. Biofortification, which involves the transfer of Se from soil to plants and animals, is currently recognized as the safest and most effective approach for Se supplementation for humans. However, Se in soil primarily exists in forms that plants cannot easily utilize, so enhancing Se transfer from soil to plants is crucial for optimal Se utilization. In this paper, we provided a comprehensive analysis of Se forms in soil. Then we summarized the strategies for enhancing Se transfer from soil to plants. These strategies include adjusting redox potential, managing soil moisture, modulating pH value, improving organic matter, optimizing ion competition, promoting beneficial microbes, and considering the synergy between plant rhizosphere and soil. Furthermore, we reviewed Se forms and metabolism after uptake into plants to better understand its role in human health. Finally, we came up with the challenges and perspectives, to provide new insights for further study in this area. This work also offers potential solutions for enhancing Se transformation from soil to plants and utilizing soil Se to produce naturally Se-rich products.