Microalgal selenium biofortification drives molecular reconfiguration of fructan metabolism in Helianthus tuberosus

Inulin-type fructans are distinctive β-(2→1)-linked fructan polymers that function as both prebiotic dietary fibers and multifunctional food ingredients, providing health-promoting effects through selective modulation of gut microbiota and offering valuable techno-functional properties for food applications. Helianthus tuberosus (Jerusalem artichoke) represents one of the richest plant sources of inulin; however, fructan accumulation is strongly influenced by genotype, environmental conditions, and metabolic regulation. Selenium (Se), an essential trace element with important roles in redox homeostasis and stress adaptation, has recently emerged as a promising biofortification target, while selenium-enriched microalgae provide a sustainable platform for converting inorganic Se into bioavailable organic forms. This review summarizes recent advances in microalgal selenium biofortification of H. tuberosus , focusing on Se uptake and metabolism, redox-mediated regulation of carbon allocation, and the molecular control of fructan biosynthesis involving key enzymes such as sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 1-fructosyltransferase (1-FFT). We further discuss how multi-omics approaches, fluxomics, CRISPR-based genome engineering, nanotechnology, and artificial intelligence-driven modeling can reveal regulatory networks underlying Se-induced inulin accumulation. Finally, we propose a precision biofortification framework integrating algal biotechnology and plant metabolic engineering to improve functional crop quality and support sustainable production of inulin-rich foods.