Proteome analysis of papaya at low temperatures reveals adaptations in cell wall metabolism in response to chilling injury

Abstract BACKGROUND Papaya is susceptible to chilling injury (CI) during low‐temperature storage. However, it is noteworthy that papaya stored at 1 °C exhibits milder CI symptoms, potentially attributed to alterations in cell wall metabolism. To unravel the cellular wall metabolic pathways underlying this abnormal CI response in papaya, our research conducted proteomic analysis on fruit stored at 1 and 6 °C for 12, 24 and 36 days. RESULTS Analysis of differentially expressed proteins (DEPs) revealed temperature as the primary driver of expression divergence, with 122 DEPs (115 downregulated, 7 upregulated) identified across three comparison groups (1–12 versus 6–12, 1–24 versus 6–24, 1–36 versus 6–36). Enrichment showed significant involvement in carbohydrate metabolism, cell wall biogenesis and β ‐galactosidase activity, with galactose metabolism as a key pathway. Further screening based on proteomic data identified 20 DEPs specifically linked to cell wall metabolism. Protein–protein interaction analyses highlighted the crucial roles of these DEPs in lignin synthesis, responses to biological stresses and overall cell wall metabolism. CONCLUSION The findings reveal that papaya stored at 1 °C modulates the expression of proteins related to cell wall metabolism, inhibiting the degradation of cell wall components. This, in turn, fortifies cell wall stability, maintains tissue integrity and ultimately mitigates the progression of CI. © 2025 Society of Chemical Industry.