Myoung-Jun Jang

As LEDs are increasingly used in mushroom production, understanding the blue-light response characteristics of the pathogenic fungus Trichoderma harzianum is important for mushroom cultivation management. In this study, T. harzianum was cultured under blue LED conditions (460 nm), with darkness as the control, and its growth, morphology, and transcriptomic responses were compared. Blue LED exposure reduced colony diameter by 21.6% and 25.2% on days 1 and 2 of cultivation, respectively, and induced sporulation on day 3. RNA-seq Trinity gene-level features were quantified, and 23,086 and 34,839 genes showed higher and lower expression under blue LED illumination, respectively. Gene Ontology (GO) analysis of candidates selected using the criteria TPM ≥ 15 and |log2FC| ≥ 1 showed that the candidates with increased expression blue LED illumination were associated with transport and xenobiotic transport, whereas the candidates with decreased expression were associated with filamentous growth, cell wall polysaccharide biosynthetic process, and UDP-glucosyltransferase activity. Among the highly responsive candidates selected using the criteria TPM ≥ 15 and |log2FC| ≥ 3, carbohydrate-active enzyme (CA-Zyme)-related genes were identified, including glycosyltransferase family (GT) 8, GT35, glycoside hydrolase family (GH) 16, GH18, GH76, and multicopper oxidase. In contrast, the candidates with decreased expression included GT2, GT20, GT35, carbohydrate esterase family 5, and GMC oxidoreductase. RT-qPCR analysis of the selected candidate genes supported the RNA-seq-based expression trends. In addition, in the RNA-seq dataset, the expression levels of the blue light response-related genes BLR-1, BLR-2, and ENV1 increased by 2.8-, 1.9-, and 4.2-fold, respectively. These findings provide phenotypic and molecular candidates for future functional studies of the blue-light response in T. harzianum.

This study explored disease symptom development and changes in relative volatile organic compound (VOC) profiles after inoculation of Trichoderma atroviride onto Lentinula edodes pilei. Phylogenetic analyses based on ITS and tef1 sequences supported identification of the inoculated strain as T. atroviride. Inoculation caused surface depression and browning, while discoloration extended from the surface into internal tissues. At 3 days after inoculation, the inoculated strain was re-isolated from T1–T3 tissues, confirming the presence of viable fungi at all sampling positions. Relative VOC profiles were compared among untreated pilei, wound-treated samples, T. atroviride cultures (TA), and samples collected from different positions after inoculation (T1–T3). PCA and heatmap analyses revealed descriptive VOC variation among treatment groups and T1–T3, although no individual VOCs differed significantly among T1–T3 after FDR correction. 6-Pentyl-2H-pyran-2-one showed the highest relative peak area percentage in TA, whereas 2(3H)-naphthalenone was consistently detected only in TA. In inoculated pilei, ylangene was detected at all positions, whereas γ-muurolene, α-muurolene, 1-naphthalenol, 3-octanone, and 1,2,4-trithiolane showed different detection patterns and relative peak area percentages among T1–T3. These findings provide a basis for quantitative validation of inoculation-associated VOC changes and potential spatial variation within the pileus.

This study investigated gene expression patterns associated with the browning of mushroom fruiting bodies caused by Pseudomonas tolaasii infection. To address this, Pleurotus ostreatus, Agaricus bisporus , and Lentinula edodes were inoculated with P. tolaasii , and morphological changes were examined, followed by transcriptome analysis to identify common and differentially expressed genes across the three species. Hydrophobin and glycoside hydrolase family 13 genes, associated with α-glucan metabolism and cell wall-related processes, were commonly downregulated, whereas laccase- and histidine kinase-related genes involved in melanin biosynthesis were significantly upregulated (log2 fold change ≥ 2, p ≤ 0.05). Notably, laccase induction represented a conserved transcriptional response to P. tolaasii infection, although the magnitude of induction varied among species. These findings provide molecular evidence linking mushroom browning to the transcriptional activation of defense-related genes and highlight laccase as a key, yet species-dependent, component of the response to P. tolaasii infection.

Salt stress is a major environmental constraint affecting plant growth and productivity. Crop wild relatives provide valuable genetic resources for stress tolerance, yet transcriptomic information for forest-derived wild species remains limited. In this study, we analyzed transcriptional responses of V. hirsuta, a crop wild relative (CWR) of legumes, after seven days of salt stress using de novo transcriptome sequencing. Seedlings were exposed to salt stress, and differentially expressed genes (DEGs) were identified between control (Vh_S0) and salt-treated (Vh_S7) plants using an FDR-adjusted threshold (q < 0.05). Gene Ontology and KEGG enrichment analyses revealed that salt-responsive DEGs were mainly involved in regulatory signaling, metabolic adjustment, redox-related processes, and macromolecular organization. Up- and down-regulated DEGs showed distinct yet overlapping enrichment patterns, indicating complex transcriptional reprogramming under salt stress. Transcription factor analysis identified bHLH, MYB, bZIP, NAC, and WRKY families as major regulators, with many families containing both up- and down-regulated members. Notably, genes associated with Na⁺/K⁺ homeostasis were consistently up-regulated and validated by qRT-PCR. These results suggest that continuous seven days salt stress adaptation in V. hirsuta involves coordinated regulation of signaling pathways, transcriptional networks, and transporter-mediated ion homeostasis, providing a valuable transcriptomic resource for crop wild relatives.

Heat stress induces oxidative stress in Pleurotus ostreatus (P. ostreatus), inhibiting the growth of both mycelium and fruiting bodies. While various studies have analyzed the physiological responses of P. ostreatus under heat stress conditions, comprehensive research comparing physiological responses in mycelium and fruiting bodies through metabolomic analysis of volatile organic compounds has not been conducted. In this study, we invested the levels of volatile organic compounds (VOCs), the activity of VOC synthesis-related enzymes, and the expression of heat resistance-related genes in mycelium and fruiting bodies exposed to heat stress. The total VOC levels measured in mycelium increased, whereas those in fruiting bodies decreased, indicating contrasting responses. In fruiting bodies, following heat stress, the synthesis of 1-Octen-3-ol was inhibited by glutathione peroxidase (GPx), and its conversion to 3-Octanone was accelerated by alcohol dehydrogenase (ADH), resulting in a significant decrease in 1-Octen-3-ol levels. In mycelium, both GPx gene expression levels and ADH activity remained unchanged under heat stress conditions, and 1-Octen-3-ol levels did not decrease. Comparison of heat resistance-related gene expression through quantitative PCR revealed that in mycelium, the expression of genes related to trehalose and heat shock proteins increased, while in fruiting bodies, the expression of genes related to antioxidant enzymes, including GPx, increased. In conclusion, we identified distinct heat resistance responses in mycelium and fruiting bodies, which had different effects on VOC synthesis, leading to contrasting changes.

Reclaimed land refers to artificially created soil formed by filling in seawater, leading to rapid ecological changes. Undeveloped reclaimed areas offer opportunities to explore previously unknown soil ecological resources. The Shihwa reclaimed land is an undeveloped area where microbiome-based studies of the microbial community have not yet been conducted. The soil from the Sihwa reclaimed land (SR, SL) showed higher pH (8.9), EC (7.5 dS/m), and Na⁺ content (13.4 cmol⁺/kg), but lower levels of organic matter and phosphorus compared to typical agricultural soils (NL, NS). These unfavorable conditions had a negative effect on lettuce growth, as both fresh and dry weights in the SL treatment (32.5 g and 0.39 g, respectively) were significantly lower than those in the NL treatment (40.4 g and 0.45 g). At the phylum level, Actinobacteria (51.6%) dominated the original reclaimed soil (SR), but after lettuce cultivation (SL), there was an increase in Cyanobacteria (25.3%) and Proteobacteria (29.4%). At the order level, Streptomycetales (35.2%) and Bacillales (13.5%) were predominant in SR, whereas in SL, Oscillatoriales (23.5%)—which have photosynthetic ability—as well as organic matter-degrading orders such as Rhodobacterales and Flavobacteriales, became dominant. For the eukaryotic community at the phylum level, Ascomycota was predominant in all samples; however, in NL, the relative proportions of Chlorophyta (22%) and Mucoromycota (8.9%) were higher, indicating increased diversity. At the order level, Eurotiales (28.5%), Hypocreales (20.2%), and Wallemiales (14.4%) were predominant in SR, but after lettuce cultivation, Wallemiales disappeared and Eurotiales increased to 40.0%. Additionally, Glomerellales and Sordariomycetes_o were detected only in SL and NL, suggesting that symbiotic fungal activity in the rhizosphere was promoted.

Fungi have a high resistance to gamma radiation. Previous studies elucidating the resistance mechanisms to gamma radiation have mainly been conducted using yeast model organisms, but molecular-level mechanisms targeting fungi have been largely unexplored. In order to examine the response of A. auricula-judae to gamma radiation, we conducted comparative transcriptome analysis using RNA-Seq on fruit bodies derived from mycelium exposed with 200 Gray of gamma radiation. A total of 69,183 unigenes were generated, and annotation was performed through two libraries. According to GO analysis, catalytic activity, cell part, and cellular process groups were identified as the major groups responding to gamma radiation. Differentially expressed genes revealed inhibited expression in amino acid metabolism, carbohydrate metabolism, and cell cycle regulation genes. Furthermore, enhanced cell death promoted resistance by eliminating unstable cells. DNA repair genes were up-regulated, indicating a common defense mechanism of fungi that increases genome integrity by repairing DNA damaged by gamma radiation. Conversely, genes related to antioxidants and laccase were down-regulated, suggesting that resistance response through resolving oxidative stress induced by gamma radiation did not occur. Our study provides valuable data for understanding not only the response of A. auricula-judae to gamma radiation but also the resistance responses of edible mushrooms to gamma radiation.

This study was conducted to investigate the growth characteristics and morphology of Pleurotus ostreatus mycelium during co-cultivation with Pseudomonas putida. For selection of the most effective Pseudomonas species in coculture, Three strains of Pseudomonas putida and one strain of Pseudomonas fluorescens were co-cultured with heuktari, one of the varieties of P. ostreatus, on NPDA agar medium to observe the growth pattern of mycelium. It was found that the microorganism affecting mycelium growth during co-cultivation was P. putida KACC 10275, and co-cultivation of these two species resulted in enhanced mycelium growth on both NPDA and sawdust agar media. Furthermore, while primordium formation and fruit body development did not occur on plates inoculated only with heuktari, fruit bodies were observed only on plates where heuktari and P. putida were co-cultured, as confirmed by cultivation in the growth chamber for the same duration.

Laccase is an enzyme that plays an important role in fungi, including lignin degradation, stress defense, and formation of fruiting bodies. Auricularia auricula-judae is a white-rot fungus in the Basidiomycota phylum, capable of delignifying wood. In this study, seven genes belonging to the laccase family were identified through de novo sequencing, containing Cu-Oxidase, Cu-Oxidase_2, and Cu-Oxidase_3 domains. Subsequently, the physical characteristics, phylogenetic relationships, protein secondary structure, and tertiary structure of the laccase family (AaLac1–AaLac7) were analyzed. Prediction of N-glycosylation sites identified 2 to 10 sites in the laccase family, with AaLac7 having the highest number of sites at 10. Sequence alignment and analysis of the laccase family showed high consistency in signature sequences. Phylogenetic analysis confirmed the relationship among laccases within the family, with AaLac3–AaLac4 and AaLac5–AaLac6 being closely positioned on the tree, exhibiting high similarity in tertiary structure predictions. This study identified and analyzed laccase family genes in Auricularia auricula-judae using de novo sequencing, offering a simple method for identifying and analyzing the laccase family in organisms with unknown genetic information.

In this study, the α-amylase inhibitory activity, α-glucosidase inhibitory activity, pancreatic lipase inhibitory activity, and Xanthine Oxidase inhibitory activity of the fruiting body extracts of 5 varieties of Agaricus bisporus (AB) were confirmed. First, the α-amylase inhibitory activity of AB12, AB13, AB18, AB34, and AB40 methanol extracts was lower than that of acarbose, a positive control, in all concentration ranges. The α-glucosidase inhibitory activity of the AB40, AB13, and AB12 methanol extracts at the extract concentration of 1.0 mg/mL was 80.5%, 81.3%, and 78.5%, respectively, similar to that of acarbose, a positive control. The pancreatic lipase inhibitory activity of the methanol extract of Agaricus bisporus fruiting body was significantly lower than that of the positive control orlistat in the concentration range of 50 ∼ 1.000 (mg/mL). The Xanthine Oxidase inhibitory activity was 0.5 ∼ 8.0 mg/mL of each extract, which was significantly lower than that of the positive control allopurinol in the same concentration range. However, the Xanthine Oxidase inhibitory activity of AB13 and AB40 at 8.0 mg/mL was about 70%, which was higher than that of other mushrooms. In conclusion, five kinds of Agaricus bisporus fruiting bodies seem to have inhibitory effects on enzymes such as α-amylase, α-glucosidase, pancreatic lipase, and Xanthine Oxidase that degrade starch and protein. In particular, it has an inhibitory effect and a reduction effect on xanthine oxidase that causes gout, so it is expected that it can be developed and used as a food or health supplement with health functional properties through future research.