Expression of UBC genes from P. bretschneideri and P. communis during fruit development and ripening, including Fruit_stage1 (15 days after full blooming (DAB)), Fruit_stage2 (30 DAB), Fruit_stage3 (55 DAB), Fruit_stage4 (85 DAB), Fruit_stage5 (115 DAB), Fruit_stage6 (mature stage), and Fruit_stage7 (fruit senescence stage). The color scale represents normalized log 2-transformed, where grey indicates a medium level, blue indicates a low level, and red indicates a high level. Circos software was used to visualize the heat map. The FPKM values of PbrUBCs and PcpUBCs are presented in Table S3. The outermost ring represents Fruit_stage7, followed by Fruit_stage6, Fruit_stage5, Fruit_stage4, Fruit_stage3, and Fruit_stage2, and the innermost ring represents Fruit_stage1.