Background/Objectives: Grapes (Vitis vinifera), particularly ‘Shine Muscat’, are prone to postharvest quality loss mainly due to poor storage tolerance. Actinomycetes are microbial resources that produce secondary metabolites that exhibit notable functional properties. Methods: This study explored the use of Streptomyces albulus Ah11601 fermentation broth (SFB) as a postharvest treatment to preserve ‘Shine Muscat’ grape quality during 6 days of room temperature storage using physiological, transcriptomic, and bioinformatics analyses to elucidate the underlying regulatory mechanism. Results: The results demonstrated that, compared to the control group stored at room temperature (25 °C) for 6 days (6D), the SFB-treated group (T6D) presented a significant delay in the decrease in fruit hardness and vitamin C content. Further investigations revealed that the 6D treatment significantly elevated lipoxygenase activity, MDA content, O₂⁻ generation rate, and H₂O₂ levels. In addition, both the 6D and T6D treatments significantly increased the activities of SOD and APX. Functional enrichment analysis revealed that the upregulated DEGs in the 6D group were predominantly enriched in pathways such as phenylpropanoid biosynthesis; flavonoid biosynthesis; phenylalanine metabolism; and stilbenoid, diarylheptanoid, and gingerol biosynthesis. The downregulated DEGs were enriched primarily in the endoplasmic reticulum protein processing pathway. In the T6D group, the upregulated DEGs were predominantly enriched in the zeatin biosynthesis pathway. In addition, significant alterations in the expression of genes associated with the ethylene and abscisic acid signaling pathways were detected. Conclusions: In conclusion, SFB treatment effectively mitigated the deterioration of the postharvest quality of ‘Shine Muscat’ grapes by preserving the cellular redox balance, regulating cytokinin and ethylene biosynthesis, and optimizing the regulation of ethylene and abscisic acid signaling.

Background: The JinEr mushroom results from the heterogeneous symbiosis of Naematelia aurantialba and Stereum hirsutum, with low-temperature storage being key for postharvest quality preservation. However, the species-specific low-temperature response patterns remain unclear. Methods: An integrated approach combining metabolomics, transcriptomics (dual-genome alignment), and spatially resolved enzyme assays was used to dissect responses at 0 °C and 4 °C. Results: The two fungi displayed distinct stress response tendencies under the studied conditions. N. aurantialba showed enhanced stress defense (DNA repair, antioxidant pathways) with defense-related enzyme activities concentrated in its apical/middle enrichment regions. S. hirsutum was observed to maintain overall metabolic activity at the pathway level, and its metabolic enzyme activities were predominant in the basal region. The symbiotic system exhibited temperature-dependent plasticity stress responses. Storage at 0 °C induced a survival-oriented response with slower crude polysaccharide degradation. In contrast, storage at 4 °C supported active metabolic defense coordination but more pronounced polysaccharide loss. Conclusions: These observed defense- and metabolism-biased differential responses suggest a cold stress-specific coordination working model within the symbiotic system under postharvest cold stress. A temperature of 0 °C is more suitable for enabling JinEr mushroom postharvest storage to retain polysaccharides. This study advances our understanding of heterogeneous symbiotic fungi’s postharvest biology and provides a temperature-targeted theoretical basis for storage optimization.