Harnessing the Rhizosphere Microbiome for Selenium Biofortification in Plants: Mechanisms, Applications and Future...

The rhizosphere microbiome plays a critical role in promoting crop health and productivity. Selenium (Se), a beneficial trace element for plants, not only enhances resistance to both abiotic and biotic stresses but also modulates soil microbial communities. Se biofortification of crops grown in seleniferous soils using selenobacteria represents an eco-friendly and sustainable biotechnological approach. Crops primarily absorb selenium from the soil in its oxidized forms, selenate and selenite, and subsequently convert it into organic Se compounds. However, the role of Se-oxidizing bacteria in soil Se transformation, bioavailability, and plant uptake remains poorly understood. In this review, systematic collection and analysis of research on selenobacteria, including both Se-oxidizing and Se-reducing bacteria, are therefore essential to elucidate their functions in enhancing crop growth and health. These insights can (i) deepen our mechanistic understanding of microbially mediated Se cycling and stress resilience and (ii) offer a novel framework for nanomicrobiome engineering aimed at promoting sustainable food production.