Transcriptome and Metabolomics Analysis of Sugar and Acid Metabolism Regulated by Different Storage Temperatures in Prunus domestica × armeniaca Fruits.

The flavor quality of postharvest Prunus domestica × armeniaca fruits is closely related to storage temperature and sugar and acid metabolism, but the synergistic regulation mechanism of key gene modules is not clear. In order to understand how flavor quality and sugar-acid metabolism regulate and interact, "Fengweihuanghou" was used as the material and stored at 0°C and 4°C for 45 days, respectively. The data of physiological indexes, transcriptome, metabolomics, and weighted gene co-expression network analysis (WGCNA) were integrated. Physiological results showed that 0°C accelerated fruit browning, whereas 4°C effectively maintained the appearance quality within 30 days. Transcriptome showed that multiple key coding enzyme genes in glycolysis and tricarboxylic acid cycle (TCA) cycle were downregulated at 0°C, and aerobic metabolism was weakened as a whole. Storing at 4°C promoted the upregulation of multiple key coding enzyme genes and enhanced the synthesis of sugar and organic acids. Metabolomics showed that the accumulation of sucrose and glucose-6-phosphate was significantly positively correlated with the expression of key genes, and 4°C was beneficial to sucrose accumulation. Module genes, such as MEturquoise, are closely related to sugar and acid components, and their expression is temperature and time dependent. In summary, 4°C positively regulates the key genes of central carbon metabolism and activates specific co-expression modules, which can better maintain the balance of sugar and acid metabolism and flavor quality within 30 days. Both temperatures are not suitable for storage for up to 45 days. Therefore, 4°C is suitable for short-term storage.