Qing Wen

Blue light is a critical signal that triggers fruiting body initiation in mushroom-forming fungi. Pleurotus ostreatus is a cultivated model mushroom. The molecular mechanisms linking light perception to primordia formation remain poorly understood. We functionally characterized the blue light receptor gene PoWC-1, a homolog of Neurospora crassa white collar 1, during morphogenesis. Antisense-mediated silencing of PoWC-1 caused a delay in primordia formation under light/dark cycles and complete arrest at the undifferentiated mycelial stage under continuous darkness, underscoring its role in developmental progression. In darkness, PoWC-1 silencing downregulated key developmental transcription factors, hom1, hom2, Pofst3, and fst4, suggesting that PoWC-1 may contribute to developmental competence independently of light. Comparative transcriptomics revealed PoWC-1 influences a range of metabolic pathways—such as glycolysis/gluconeogenesis, the pentose phosphate pathway, and amino sugar metabolism—that may support the energetic and biosynthetic demands of fruiting initiation. In addition, PoWC-1 appears to affect upstream signaling components, including the MAPK pathway and the two-component system, along with a suite of downstream transcription factors. These findings suggest that PoWC-1 functions as a key regulator integrating blue light signals into a multi-layered network involved in metabolic reprogramming, signal transduction, and transcriptional regulation during primordia formation in P. ostreatus. Collectively, this study provides a molecular framework for understanding photomorphogenesis in edible mushrooms.

Pleurotus ostreatus (Jacq.) P. Kumm is the second most cultivated edible mushroom worldwide. Temperature is one of the main environmental factors affecting the growth and fructification of mushrooms. However, the effects of ambient temperature on the growth, development, and production of bag-cultured P. ostreatus are still unclear. In this study, eight ambient temperatures (15 °C, 18 °C, 20 °C, 22 °C, 25 °C, 28 °C, 30 °C, and 32 °C) were used to cultivate P. ostreatus mycelia with cottonseed hull as substrate. Then, the agronomic traits and the activities of substrate-degrading and antioxidant enzymes were determined. The mycelial growth and fructification of P. ostreatus differed significantly under different temperatures, and 22 °C was the optimum temperature for mycelial culture when we comprehensively analyzed all the agronomic traits. The mycelial growth rate and the biological efficiency under 22 °C were 0.56 cm/d and 99.53%, respectively. Furthermore, there were also significant differences in the activities of substrate-degrading enzymes and antioxidant enzymes under different ambient temperatures. The highest activities of lignocellulose-degrading enzymes (laccase, xylanase, and cellulase), amylase, and proteinase at the vegetative growth stage occurred at 15–22 °C, 20–22 °C, and 22–30 °C, respectively. The highest activities of superoxide dismutase, peroxidase, and catalase at the vegetative growth stage occurred at 28–30 °C. This study provides a reference temperature for bag-cultured P. ostreatus.

Pleurotus ostreatus (Jacq.) P. Kumm has high medicinal value, but few studies exist on regulating secondary metabolite biosynthesis. Environmental factors play a substantial role in the accumulation of microbial secondary metabolites. In this study, the effects of heat stress (24 h) and salicylic acid (0.05 mmol/L) treatment on the secondary metabolism of P. ostreatus were analyzed by metabolome, transcriptome, and gene differential expression analysis. Metabolome and transcriptome analyses showed that salicylic acid significantly increased the accumulation of antibiotics and polyketones, while heat stress increased the accumulation of flavonoids, polyketones, terpenoids, and polysaccharides. The content and the biosynthetic genes expression of heparin were markedly increased by heat stress, and the former was increased by 4565.54-fold. This study provides a reference for future studies on secondary metabolite accumulation in edible fungi.

Pleurotus ostreatus (Jacq.) P. Kumm is cultivated worldwide, and its growth is seriously threatened by heat stress. Here, we performed a comprehensive analysis to investigate the influence of the phytohormone salicylic acid (SA) in P. ostreatus under HS. The results showed that the hyphal growth recovery rate and the antioxidant capacity of P. ostreatus increased with exogenous SA application (0.01 mmol/L and 0.05 mmol/L) after HS treatment. Metabolomic and transcriptomic analyses showed that SA application (0.05 mmol/L) weakened central carbon metabolism to allow cells to survive HS efficiently. In addition, SA shifted glycolysis to one-carbon metabolism to produce ROS scavengers (GSH and NADPH) and reduced ROS production by altering mitochondrial metabolism. SA also maintained nucleotide homeostasis, led to membrane lipid remodeling, activated the MAPK pathway, and promoted the synthesis of cell-wall components. This study provides a reference for further study of SA in microorganisms.