Identification of two ERF17 genes in the apple genome. A, Phylogenetic analysis of homologous ERF17 transcription factors. MDP0000704216 and MDP0000649022 locate on apple chromosome 2 (Chr2) and chromosome 15 (Chr15), respectively. The numbers on the tree represent nucleotide substitutions. B, Relative expression of MDP0000704216 (left) and MDP0000649022 (right) in peels of cv Red Fuji (gray) and cv Zisai Pearl (black) various days after flower blossom (DAFB). An actin fragment was amplified as an internal control. Values are means ± sd (n = 3). Asterisks indicate statistically significant differences by Student’s t test (*, P < 0.05 and **, P < 0.01) compared with cv Red Fuji peel. ND, Not detected.