Anthocyanin biosynthesis in goji berry is inactivated by deletion in a bHLH transcription factor LrLAN1b promoter.

This article investigates the molecular basis for the loss of anthocyanin pigmentation in white goji berry (Lycium ruthenicum Murray), a natural variant of black goji berry known for its rich anthocyanin content. The study identifies a 229 base pair deletion in the promoter region of the bHLH transcription factor gene LrAN1b in white goji, which removes critical MYB- and bHLH-binding elements necessary for LrAN1b expression. This deletion disrupts the formation of MYB–bHLH–WD40 (MBW) transcriptional complexes involving LrAN2-like (a MYB factor), LrJAF13 (a bHLH factor), and LrAN11 (a WD40 protein), thereby inactivating anthocyanin biosynthesis. Functional assays, including transient complementation and virus-induced gene silencing, confirm that LrAN1b positively regulates anthocyanin accumulation, and its loss leads to the white fruit phenotype. The findings elucidate a hierarchical regulatory network controlling anthocyanin biosynthesis in black goji berry and provide insights into natural variation affecting fruit coloration.