Decoding the material basis and regulatory mechanism of aroma loss in 'Xuxiang' kiwifruit during cold storage: Insights from multi-omics analysis.

Long-term cold storage typically induces substantial loss of characteristic aroma and deterioration of sensory quality in kiwifruit; however, the underlying material basis and regulatory mechanisms remain poorly understood. In this study, an integrated approach combining intelligent sensory evaluation, quantitative descriptive analysis (QDA), and sensomics was employed to delineate the material basis of cold storage-induced aroma loss in 'Xuxiang' kiwifruit. Metabolomic and transcriptomic profiling was subsequently performed to elucidate the regulatory mechanisms. Results showed that short-term cold storage (≤ 4 weeks) significantly enhanced the "fruity" note and improved aroma quality, whereas long-term cold storage markedly attenuated the characteristic "fruity" and "grassy" notes and progressively reduced overall odor acceptability. Sensomics analysis identified 14 differential key odorants (DKOs), among which the pronounced decreases in (Z)-3-hexenal, (Z)-3-hexen-1-ol, ethyl butyrate, and linalool constituted the core material basis for aroma loss. Further integrated multi-omics analysis revealed that long-term cold storage suppressed the expression of key aroma biosynthetic genes, including AchLOX2, AchDXS, AchGGPS1, AchTPS3, and AchNCED, thereby impairing the biosynthesis of DKOs via fatty acid-derived and terpenoid pathways. Upstream regulatory analysis indicated that the marked reduction in endogenous jasmonic acid (JA) content during cold storage likely attenuated the transcriptional activation activity of NAC and WRKY transcription factors (TFs), while enhancing the repressive effect of TIFY TFs. This synergistic regulation may contribute to the downregulation of key aroma biosynthetic genes, ultimately leading to impaired aroma metabolism and the loss of DKOs. These findings provide a theoretical foundation for the elucidation of the molecular mechanisms of cold storage-induced aroma loss in kiwifruit and the development of targeted postharvest regulation strategies.