Transcriptomic and Metabolomic Studies Reveal Mechanisms of Effects of CPPU-Mediated Fruit-Setting on Attenuating Volatile Attributes of Melon Fruit

N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU), a synthetic cytokinin-active compound, is widely applied to induce parthenocarpic fruit set and enhance melon enlargement (Cucumis melo L.). CPPU may also influence quality; however, the mechanisms through which this occurs remain unknown. We investigated differences in volatile emissions between by (C) seeded artificial pollination (P). Gas chromatography–mass spectrometry (GC–MS) analysis revealed that six organic compounds (VOCs) emitted P-group fruits were not detected C-group fruits. The relative abundances of another 14 VOCs CPPU-treated less than those RNA sequencing indicated total 1027, 994, 743 differentially expressed genes (DEGs) C20 (treatment with 20 mg·L–1 CPPU) vs. P, P-C20 (pollination followed mg·L−1 treatment) treatments, respectively. Compared Gene Ontology (GO) Kyoto Encyclopedia Genes Genomes (KEGG) databases, DEGs related fatty acid degradation metabolism, contribute production, enriched. In particular, such as carotenoid cleavage dioxygenase (CCD)-, lipoxygenase (LOX)-, alcohol dehydrogenase (ADH)-, acyltransferase (ATT)-related closely formation volatiles. summary, our study provides metabolic transcriptomic atlas, reveals impact on VOCs, enhances understanding towards generally reducing quality fruit.