Functional Analysis of the Anthocyanin-Associated Glutathione S-Transferase Gene StGST1 in Potato

Anthocyanins are biosynthesized on the cytoplasmic surface of the endoplasmic reticulum and then transported to the vacuole for storage. Glutathione S-transferases (GSTs) are involved in the transport of anthocyanins. However, the regulatory mechanism of GSTs in potato is unclear. In this study, the glutathione S-transferase gene StGST1 was isolated from potato and characterized. Expression analysis revealed that StGST1 transcript levels were higher in pigmented tubers than in white tubers. Overexpression of StGST1 promoted anthocyanin accumulation in the tuber. Transient luciferase analysis revealed that the promoter of StGST1 was activated by the transcription factors StAN2 and StAN11. These results indicated that StGST1 promotes anthocyanin accumulation in potato tubers. These findings have important implications for improvement of anthocyanin accumulation in pigmented potato tubers.