Fig. 1.

Sucrose induces anthocyanin and PA accumulation by promoting the expression of the regulatory and biosynthetic genes. (A, B) Anthocyanin pigmentation phenotype (A) and anthocyanin contents (B) of 20-day-old in vitro apple shoot cultures treated with different concentrations (1, 3, and 6%) of sucrose and mannitol. (C, D) PA staining and content determination in apple leaves of the shoot cultures in (A). In (B) and (D), FW, fresh weight. Error bars represent the SDs, which were analyzed based on >9 replicates. (E, F) Expression analysis of anthocyanin- and PA-related genes with qRT-PCR in the plants shown in (A). 18S was used as the internal control. Error bars represent the SD based on three independent replicates. In (B), (D), (E), and (F), statistical significance was calculated by the LSD test with DPS software, P<0.05.