Integrated metabolomic and transcriptomic analysis revealed the role of PbrCYP94B in wax accumulation in pear fruit after bagging treatment.

Preharvest fruit bagging is a safe and environmentally friendly production measure. Cuticular wax, as the first protective layer on the fruit surface, has important functions. However, the effects of preharvest bagging on cuticular wax synthesis in pears and the related molecular mechanisms are still unclear. Here, the impact of fruit bagging with different materials on cuticular wax synthesis in pear fruit, and the underlying molecular mechanism, were revealed from metabolomic, transcriptomic, morphological, and molecular biological perspectives. Our results revealed that, compared with that in the not bagged (NB) treatment group (0.59 mg/cm), the total wax concentration was 1.32- and 1.37-fold greater in the single-layered white paper bag (WPB, 1.37 mg/cm) and double-layered yellow-white paper bag, (YWPB, 1.40 mg/cm) treatment groups, while it was slightly lower in the double-layered yellow-black paper bag (YBPB, 0.45 mg/cm) group, which was consistent with the scanning electron microscopy (SEM) results. Integrated metabolomic and transcriptomic analysis revealed 29 genes associated with cuticular wax synthesis. Overexpression of PbrCYP94B, which is a key gene in the wax synthesis pathway in pear fruit, increased the total wax and alkane contents. This study provides valuable insights for the creation of new pear germplasms with high wax contents.