Transcriptomic and Gas Chromatography–MassSpectrometry Metabolomic Profiling Analysis of the Epidermis ProvidesInsights into Cuticular Wax Regulation in Developing ‘Yuluxiang’Pear Fruit

The layer of cuticular wax covering fruits plays important roles in protecting against disease, preventing nonstomatal water loss and extending shelf life. However, the molecular basis of cuticular wax biosynthesis in pear (Pyrus) fruits remains elusive. Our study thoroughly investigates cuticular wax biosynthesis during pear fruit development from morphologic, transcriptomic and gas chromatography-mass spectrometry (GC-MS) metabolomic perspectives. Our results showed that cuticular wax concentrations increased during the early stage (20-80 days after full bloom, DAFB) from 0.64 mg/cm2 (50 DAFB) to 1.75 mg/cm2 (80 DAFB), and then slightly decreased to 1.22 mg/cm2 during the fruit ripening period (80-140 DAFB). Scanning electron microscopy (SEM) imaging indicated that wax plate crystals increased, and wax structures varied during the pear fruit development. The combined transcriptomic and metabolomic profiling analysis revealed 27 genes, including 12 genes encoding transcription factors (TFs) and a new str...