Integrated Transcriptomics and Metabolomics Provide Insight into Degeneration-Related Molecular Mechanisms of Morchella importuna During Repeated Subculturing

Author: mycolabadmin
5/30/2025
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Summary

Morel mushrooms are prized edible fungi that unfortunately degrade when repeatedly cultured in the laboratory, becoming slower-growing and less productive. Researchers used advanced genetic and chemical analysis to discover that degeneration occurs when the mushroom stops producing flavonoids, natural antioxidants that protect cells from damage. A specific gene called NR-PKS is responsible for making these protective flavonoids, and it shuts down in degraded strains. The study suggests that preservation methods using cold storage or adding antioxidants could help maintain healthy, productive morel cultures.

Background

Morchella importuna is a highly valued edible fungus that undergoes strain degeneration during repeated subculturing, characterized by reduced mycelial growth, altered pigmentation, and decreased productivity. Previous studies on strain degeneration have identified various mechanisms including viral infections, reduced enzyme synthesis, and accumulation of harmful substances, but the specific molecular mechanisms in M. importuna remain poorly understood.

Objective

This study aimed to investigate the molecular mechanisms underlying strain degeneration in M. importuna during repeated subculturing using integrated transcriptomics and metabolomics approaches. The research sought to identify key genes and metabolic pathways involved in the degeneration process and to elucidate the role of secondary metabolites, particularly flavonoids, in strain viability.

Results

Analysis identified 699 differentially expressed metabolites and 2691 differentially expressed genes between normal and degenerated strains. DEMs were predominantly enriched in secondary metabolite biosynthesis pathways, particularly flavonoids and indole alkaloids, while DEGs were mainly associated with metabolic pathways and genetic information processing. A non-reducing polyketide synthase (NR-PKS) gene was identified as critical for flavonoid biosynthesis, showing significantly reduced expression in degenerated strains, correlating with markedly decreased flavonoid content (15 compounds showed significant reduction).

Conclusion

M. importuna degeneration results from systemic dysregulation of gene expression networks and metabolic pathway reorganization, with reduced intracellular flavonoid synthesis weakening antioxidant capacity and causing oxidative damage. The findings suggest that avoiding frequent subculturing, implementing low-temperature dormancy, or supplementing with antioxidants could slow degeneration, though further investigation of the NR-PKS gene’s specific functions and regulation is warranted.

Published in:Journal of Fungi (Basel),
Study Type:Experimental Research,
Source: PMID: 40558932, DOI: 10.3390/jof11060420