The PuMYB93–PuGSTF12 regulatory module promotes anthocyanin accumulation in ‘Nanhong’ pear fruit

Anthocyanins are important flavonoid pigments in the coloration of fruits. To identify candidate genes involved in anthocyanin accumulation, metabolic and transcriptome analyses were conducted in ‘Nanguo’ pear and its red sport cultivar ‘Nanhong’ pear. The results showed that ‘Nanhong’ pear had significantly higher anthocyanin and flavonol contents. Additionally, transcriptomic analysis showed that there were significant differences in the expression of genes involved in phenylpropanoid and flavonoid biosynthesis pathways between the two cultivars, with PuGSTF12 being the most upregulated gene in the ‘Nanhong’ cultivar. Further analysis identified a novel MYB transcription factor (PuMYB93), and its silencing repressed PuGSTF12 expression and anthocyanin accumulation, suggesting it plays an essential role in the regulation of anthocyanin biosynthesis. Moreover, yeast one-hybrid analysis, electrophoretic mobility shift assay, and β-glucuronidase assay indicated that PuMYB93 can directly bind to the PuGSTF12 promoter to positively regulate its expression. Additionally, PuGSTF12 silencing suppressed the coloration of PuMYB93-OE peels, suggesting that PuGSTF12 act downstream of PuMYB93. Overall, the findings of this study show that PuMYB93 promotes anthocyanin transport in pears by regulating PuGSTF12 expression to further enhance anthocyanin accumulation.