A flavonoid 3’-hydroxylase regulates pink tuber skin in potato

The Pink locus, responsible for pink tuber skin in potato, was fine-mapped to chromosome 3, and the anthocyanin biosynthesis gene StF3′H was identified as the causal gene. Promoter variations in StF3′H regulate its expression and determine pink pigmentation, and the Red ( R ) locus acts epistatically over the Pink locus. The tubers of potato ( Solanum tuberosum L.) exhibit diverse colors, primarily resulting from different levels of anthocyanin pigments. While the loci regulating the accumulation of red and purple pigments have been reported, the regulatory mechanism underlying the biosynthesis of pink anthocyanins in potato remains unclear. In this study, we identified the pink tuber skin locus Pink through a bulked-segregant analysis sequencing approach using a BC 1 S 1 population segregating for tubers with red, pink, or yellow skin. We narrowed down the location of Pink to a 265-kb interval on chromosome 3. Metabolomic and transcriptomic analyses revealed the anthocyanin biosynthesis gene Flavonoid 3’-hydroxylase ( StF3’H ) as the candidate gene. Genetic transformation assays demonstrated that StF3’H is essential for the production of tubers with pink skin. Furthermore, we showed that the red tuber skin locus ( R ) is epistatic to Pink . These findings provide a new theoretical basis for the development of colored potatoes through molecular breeding and offer an important reference for exploring the complex regulatory mechanisms of anthocyanin biosynthesis in potatoes.