Transcriptome-Based WGCNA Analysis Reveals the Mechanism of Cold Resistance in Chinese Caterpillar Mushroom Ophiocordyceps sinensis (Ascomycota)

Ophiocordyceps sinensis, the dominant asexual-stage fungus in Chinese cordyceps, exhibits growth inhibition under cold stress. Understanding its cold adaptation mechanisms is therefore crucial for advancing artificial cultivation. In this study, O. sinensis was subjected to -2°C for varying durations (0, 10, 30, 50, and 70 d) to investigate cold stress effects on growth, physiological responses, and transcriptomic profiles. Prolonged low-temperature exposure induced transient growth promotion followed by sustained inhibition. Key stress indicators including H2O2 (1.75-7.1-fold increase) and O2- (0.5-6.5-fold increase) were significantly elevated. Both enzymatic antioxidants (SOD, CAT) and non-enzymatic metabolites (polysaccharides, mannitol, betaine, melanin) demonstrated critical roles in mitigating cold stress damage. Transcriptome analysis identified 10,291 significantly differentially expressed genes. Weighted gene co-expression network analysis (WGCNA) further revealed 8 hub genes (HK, DDC, COMT, PRDX5, TREH, CAT, POD, TYR), predominantly enriched in tyrosine metabolism, carbohydrate metabolism, peroxisomal pathways, and betalain biosynthesis. These findings provide molecular insights into the cold resistance mechanisms of O. sinensis, facilitating the industrialization of Chinese Cordyceps cultivation.