Condition-Specific Transcriptional and Metabolic Divergence in the Dual-Fungal Symbiosis of JinEr Mushroom Under Postharvest Low-Temperature Stress

TL;DR

This study explores how two fungi in the JinEr mushroom respond differently to cold storage temperatures, affecting their survival and metabolism.

Contribution

The study reveals condition-specific transcriptional and metabolic divergence in a dual-fungal symbiosis under postharvest low-temperature stress.

Findings

N. aurantialba showed enhanced stress defense and antioxidant pathways at 0 °C.

S. hirsutum maintained metabolic activity and had enzyme activities in the basal region.

Storage at 0 °C preserved polysaccharides better than 4 °C.

Abstract

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.

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