Abstract

Glycosylation, a biochemical process occurring on the endoplasmic reticulum (ER) and Golgi apparatus, contributes to anthocyanin stability and diversity in plants. This modification requires nucleotide sugars as activated glycosyl donors, which serve as essential substrates for glycosylation within these organelles. Nucleotide sugar transporters (NSTs) mediate cytosolic-to-lumen translocation of these donors; however, their functional role in sweetpotato remains unclear. Here, a key NST gene IbSLC35F1 was cloned and identified in sweetpotato. Subcellular localization revealed IbSLC35F1 distributed to the ER, harboring a signature NST transmembrane domain architecture. IbSLC35F1 expression levels exhibited a positive correlation with anthocyanin content in storage roots. Functional characterization confirmed its participation in translocating diverse sugars, demonstrating broad substrate specificity. Overexpression of IbSLC35F1 significantly elevated anthocyanin content in sweetpotato storage roots, whereas RNA interference (RNAi)-mediated suppression reduced accumulation. Binding assays demonstrated that IbMYB1 transcriptionally activates IbSLC35F1 , which in turn modulates anthocyanin accumulation by regulating the expression of anthocyanin biosynthetic genes as well as transport genes.