Comparative analysis of transcrptome profiling to identify genes involved in bulged surface of pear fruits (Pyrus bretschneideri Rehd. cv. Yuluxiangli)

Background: Pear (Pyrus spp.) belongs to the genus Pyrus, in the family Rosaceae. Some varieties of pear fruits exhibit bulged surface, which seriously affect the quality and commodity value. In this study, we performed anatomical, physiological and transcriptomic analysis, to explore the mechanism of paclobutrazol (PBZ) on the bulged surface of pear fruits. Results: The vascular bundles of flesh were more evenly distributed and the cells arranged more compactly with smaller size. However, the auxin (IAA) content of flesh decreased significantly when treated with PBZ. Further, the GO and KEGG analysis of differentially expressed genes (DEGs) showed that auxin, phenylpropanoid metabolic pathways and transcriptional factor genes were significantly enriched on the relieved bulged surface of pear fruits. The promoter region analysis of selected DEGs showed that some genes contained auxin responded cis-elements. Conclusion: We conclude that PBZ might play a negative role in the cell division, cell elongation and vascular bundle development on bulged surface of pear fruits through the involvement of auxin related genes. This study will provide theoretical basis for the regulation of bulged surface of pear fruits by growth retardant agent.