Fig. 1: The contents of soluble sugars and anthocyanin and the relative expression levels of genes encoding transcription factors involved in the biosynthesis of anthocyanin in ‘Hongcui 1’ apple during fruit development.

a Flesh cross-sectional view of ‘Hongcui 1’ apple during development. b The contents of soluble sugars and anthocyanin. c The relative transcript levels of genes encoding transcription factors involved in the biosynthesis of anthocyanin.