Ganoderma lucidum is used widely in oriental medicine to treat obesity and metabolic diseases. Bioactive substances extracted from G. lucidum have been shown to ameliorate dyslipidemia, insulin resistance, and type 2 diabetes in mice via multiple 5′ AMP-activated protein kinase (AMPK)-mediated mechanisms; however, further studies are required to elucidate the anti-obesity effects of G. lucidum in vivo. In this study, we demonstrated that 3% G. lucidum extract powder (GEP) can be used to prevent obesity and insulin resistance in a mouse model. C57BL/6 mice were provided with a normal diet (ND) or a high-fat diet (HFD) supplemented with 1, 3, or 5% GEP for 12 weeks and the effect of GEP on body weight, liver, adipose tissue, adipokines, insulin and glucose tolerance (ITT and GTT), glucose uptake, glucose-metabolism related proteins, and lipogenesis related genes was examined. GEP administration was found to reduce weight gain in the liver and fat tissues of the mice. In addition, serum parameters were significantly lower in the 3% and 5% GEP mice groups than in those fed a HFD alone, whereas adiponectin levels were significantly higher. We also observed that GEP improved glucose metabolism, reduced lipid accumulation in the liver, and reduced adipocyte size. These effects may have been mediated by enhanced AMPK activation, which attenuated the transcription and translation of lipogenic genes such as fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1), and sterol regulatory element-binding protein-1c (SREBP1c). Moreover, AMP-activated protein kinase (AMPK) activation increased acetyl-CoA carboxylase (ACC), insulin receptor (IR), IR substrate 1 (IRS1), and Akt protein expression and activation, as well as glucose transporter type 1/4 (GLUT1/4) protein production, thereby improving insulin sensitivity and glucose metabolism. Together, these findings demonstrate that G. lucidum may effectively prevent obesity and suppress obesity-induced insulin resistance via AMPK activation.

Tricholoma matsutake is an ectomycorrhizal fungus that has obligate symbiotic relationships with Pinus densiflora. Its fruiting body has a distinctive flavor and is traded at a high price. Thus, it has been a significant source of income for rural communities in Korea. We hypothesized that biotic factors considerably influence the formation of the T. matsutake mushroom, and the soils producing T. matsutake share similar microbial characteristics. Therefore, the present study aimed to detect the specific fungal and bacterial groups in T. matsutake production soils (shiro+) and nonproduction soils (shiro−) of the Bonghwa and Yanyang regions via next-generation sequencing. In a total of 15 phyla, 36 classes, 234 genera of bacteria, six phyla, 29 classes, and 164 genera of fungi were detected from four samples at both sites. The species diversity of shiro+ soils was lower than the shiro− samples in both the fungal and bacterial groups. In addition, we did not find high similarities in the microbial communities between the shiro+ soils of the two regions. However, in the resulting differences between the fungal communities categorized by their trophic assembly, we found a distinguishable compositional pattern in the fungal communities from the shiro+ soils and the shiro− soils of the two sites. Thus, the similarity among the microbial communities in the forest soils may be due to the fact that the microbial communities in the T. matsutake dominant soils are closely associated with biotic factors and abiotic factors such as soil properties.

Various fungi including Cordyceps farinosa, an entomopathogenic fungus, can produce steroidal triterpenoids. Protostadienol (protosta-17(20)Z,24-dien-3β-ol) is a precursor of steroidal triterpenoid compounds. To identify oxidosqualene cyclase (OSC) gene candidates involved in triterpenoid biosynthesis, genome mining was performed using Illumina sequencing platform. In the sequence database, two OSC genes, CfaOSC1 and CfaOSC2, in the genome of C. farinosa were identified. Predicted amino-acid sequences of CfaOSC2 shared 66% similarities with protostadienol synthase (OSPC) of Aspergillus fumigatus. Phylogenetic analysis showed a clear grouping of CfaOSC2 in the OSPC clade. Function of CfaOSC2 was examined using a yeast INVSc1 heterologous expression system to endogenously synthesize 2,3-oxidosqualene. GC–MS analysis indicated that CfaOSC2 produced protosta-13(17),24-dien-3β-ol and protostadienol at a 5:95 ratio. Our results demonstrate that CfaOSC2 is a multifunctional triterpene synthase yielding a predominant protostadienol together with a minor triterpenoid. These results will facilitate a greater understanding of biosynthetic mechanisms underlying steroidal triterpenoid biosynthesis in C. farinosa and other fungi.

Tricholoma matsutake has been the most valuable ectomycorrhizal fungi in Asia because of its unique flavor and taste. However, due to the difficulty of artificial cultivation, the cultivation of T. matsutake has relied on natural growth in forests. To cultivate the T. matsutake artificially, microorganisms in fairy rings were introduced. In this study, we isolated 30 fungal species of microfungi from the soil of fairy rings. Among them, one single fungal strain showed a promoting effect on the growth of T. matsutake. The growth effect was confirmed by measuring the growth area of T. matsutake and enzyme activities including α-amylase, cellulase, and β-glucosidase. In comparison with control, microfungal metabolite increased the growth area of T. matsutake by 213% and the enzyme activity of T. matsutake by 110–200%. The isolated fungal strain was identified as Penicillium citreonigrum by BLAST on the NCBI database. The Discovery of this microfungal strain is expected to contribute to artificial cultivation of T. matsutake.

Pseudomonas tolaasii, the causal agent of bacterial brown blotch disease, is a major threat to the yield and quality of oyster mushroom (Pleurotus ostreatus). To investigate the molecular basis of cultivar-dependent resistance, we performed comparative transcriptome analysis using the resistant cultivar ‘Aenutari’ (KMCC01220; AE) and the susceptible cultivar ‘Dahyun’ (KMCC04942; DH) under P. tolaasii challenge. The two cultivars showed contrasting phenotypic and transcriptomic responses after pathogen inoculation. DH exhibited visible disease symptoms and severe mycelial growth inhibition, with relative mycelial growth reduced to 33.97 ± 2.53% of the control, whereas AE maintained a relatively resistant phenotype and higher mycelial growth under pathogen challenge, reaching 51.19 ± 3.72% of the control. Consistent with these phenotypic differences, DH showed extensive transcriptional reprogramming, with 3585 up-regulated and 4377 down-regulated differentially expressed genes (DEGs). In contrast, AE showed a much narrower transcriptional response, with 181 up-regulated and 71 down-regulated DEGs. Functional enrichment analysis indicated that pathogen-responsive DEGs in AE were mainly associated with carbohydrate metabolism, extracellular regions, redox-related processes, and ion transport. In cultivar-wise comparisons under pathogen-inoculated conditions, genes highly expressed in AE were enriched in RNA splicing, mRNA processing, mitochondrial organization, mitochondrial gene expression, transmembrane transport, oxidoreductase activity, and sterol-related metabolism. These results indicate that the resistant phenotype of AE is associated with a more limited pathogen-induced transcriptional perturbation and the relative enrichment of gene modules related to RNA processing, mitochondrial organization and gene expression, membrane transport, redox-related processes, and sterol metabolism. This study provides a transcriptomic framework for understanding cultivar-dependent responses to bacterial brown blotch disease in oyster mushroom.