Characterization of blueberry glutathione S-transferase (GST) genes and functional analysis of VcGSTF8 reveal the role of ‘MYB/bHLH-GSTF’ module in anthocyanin accumulation

Blueberries (Vaccinium corymbosum) are renowned for their rich anthocyanin content, which not only endows them with exceptional nutritional and health benefits but also holds significant potential for industrial applications. Glutathione S-transferases (GSTs) have emerged as pivotal players in the transportation and accumulation of anthocyanins across various plant species. To identify GSTs associated with blueberry anthocyanin dynamics, we performed a comprehensive genomic and transcriptomic survey of blueberry GST genes. We further explored the role of a promising candidate, VcGSTF8, through a transgenic complementation approach in the Arabidopsis tt19 mutant. Additionally, we delved into the regulatory interactions between anthocyanin biosynthesis transcription factors (TFs), namely VcMYB-1 and VcAN1, and the VcGSTF8 promoter using yeast one-hybrid (Y1H) assays. Totally, we identified 104 VcGSTs encoding proteins containing both GST_C and GST_N domains. Three Phi (F) subfamily VcGSTs (VcGSTF8, VcGSTF19 and VcGSTF21) were identified as key candidates linked to anthocyanin metabolism. VcGSTF8, showing the highest homology to the Arabidopsis AtTT19, was able to restore anthocyanin levels in the tt19 mutant upon heterologous overexpression. Furthermore, we found that both VcMYB-1 and VcAN1 could bind to the VcGSTF8 promoter, suggesting the expression of VcGSTF8 is regulated by anthocyanin biosynthesis TFs. This study not only uncovers the GST genes pivotal to anthocyanin metabolism in blueberries but also elucidates the significant contribution of the ‘MYB/bHLH-GSTF’ module to the orchestration of anthocyanin accumulation. [Display omitted] •VcGSTF8, VcGSTF19 and VcGSTF21 are anthocyanin-related GSTs in blueberry.•Heterologous overexpression of VcGSTF8 can restore the anthocyanin accumulation of the Arabidopsis tt19 mutant.•The ‘MYB/bHLH-GSTF’ module contributes greatly to anthocyanin accumulation.