Li Zou

Poria cocos (syn. Wolfiporia cocos) is an obligate saprophytic fungus that can produce sclerotia only when cultivated on pine wood. Despite its wide cultivation, the nutritional adaptation of this fungus to pine substrate and the host defensive responses triggered during colonization remain poorly characterized. Elucidating how Poria cocos colonizes pine and triggers host defenses is critical to uncover its nutrient dependence. GO and KEGG analyses revealed that protein degradation, carbon metabolism, protein processing in the endoplasmic reticulum, and proteasome pathways were the major enriched pathways, indicating that a large amount of pine wood protein was degraded after Poria cocos colonization. Consistent with these omics signatures, the fungus acquired its primary nitrogen source via breakdown of pine structural and metabolic proteins, while pine carbohydrates acted as its main carbon source. Nutritional profiling confirmed the depletion of soluble protein and total sugars in pine wood, alongside elevated defensive polyphenols and flavonoids, reflecting an active stress response from viable pine parenchyma cells upon colonization. No significant shifts in mineral element concentrations were detected in colonized pine wood, indicating that Poria cocos selectively absorbs target minerals without altering the overall mineral pool of host wood tissue. Collectively, this work elucidates the core nutritional strategy of Poria cocos during pine colonization and identifies key molecular clues to advance optimized artificial cultivation, laying a solid theoretical foundation for revealing its obligate saprophytic lifestyle.

Sanghuangporus baumii, a medicinal macrofungus, remains unexplored in its response to aluminum stress, despite the widespread environmental relevance of this metal. This study investigated the dose-dependent effects of Al³⁺ on mycelial growth and metabolic regulation. Exposure to 1 mM Al³⁺ moderately stimulated growth (1.11-fold of control) and induced mild oxidative stress, which activated an effective antioxidant response—including increased SOD, CAT, and POD activities and elevated reduced glutathione content—thereby maintaining redox balance and increasing soluble sugar content. In contrast, 10 mM Al³⁺ led to pronounced intracellular Al³⁺ accumulation, severe growth inhibition, and marked oxidative damage, accompanied by impairment of the antioxidant system, yet a marked increase in total triterpenoid content (1.72-fold). Transcriptomic analysis identified 642 and 3019 differentially expressed genes (DEGs) in the 1 and 10 mM Al³⁺ treatments, respectively. KEGG enrichment analysis revealed concentration-dependent alterations in pathways related to peroxisome function, glutathione metabolism, starch and sucrose metabolism, and terpenoid backbone biosynthesis. Collectively, these findings suggest that Al³⁺ modulates S. baumii growth and metabolism in a dose-dependent manner, with redox remodeling as a potential mechanism, offering novel insights into fungal metal adaptation and the targeted modulation of medicinal metabolite production.

Geastrum is a typical saprotrophic genus with nearly 130 species distributed worldwide, yet its infrageneric classification has traditionally relied on morphological characteristics whose phylogenetic significance remains uncertain. Here, we revisit infrageneric concepts in Geastrum using Chinese material, integrating detailed morphological observations with multi-locus phylogenetic analyses. Eight specimens collected from temperate forests in Northeast and East China yielded three new species: G. capillitiononramosum sp. nov ., G. villopannosum sp. nov ., and G. kunyuense sp. nov . These species share a sessile endoperidial body lacking a collar and apophysis, a distinctly delimited fibrillose peristome, and globose to subglobose basidiospores with columnar ornamentation but differ mainly in the structure of the mycelial layer and the branching and ornamentation of capillitial hyphae. Phylogenetic analyses based on a concatenated ITS–nrLSU– rpb1 dataset recovered 12 well-supported clades and confirmed the distinct phylogenetic positions of the three new species. The resulting topology further demonstrates that several traditional infrageneric groupings defined by key morphological traits, such as the hygroscopic behavior of the exoperidium and debris-encrusted mycelial layers, are only partially congruent with molecular relationships, reflecting repeated character evolution across distant lineages. Nevertheless, specific combinations of peristome structure, mycelial layer features, and capillitial morphology remain informative at the species level. With the descriptions of three new species and an updated key to 43 Chinese taxa, this study refines current knowledge of Geastrum diversity in China and provides new evidence for reassessing infrageneric classification within the genus.

Triterpenoids derived from Sanghuangporus baumii exhibit significant pharmacological activities. However, their production remains limited due to the naturally low yield of triterpenoids and insufficient knowledge of the biosynthetic pathway. S. baumii strain DL102 was isolated, and the effects of Mn²+ on its mycelial growth and metabolism were assessed. Treatment with 1 mM Mn²+ significantly enhanced mycelial biomass accumulation, increasing by 0.42 g/L compared to the Mn0 group. This increase was associated with enhanced soluble sugar content and the upregulation of the expression of key metabolic genes. Furthermore, total triterpenoids content peaked at 10 mM Mn²+ (28.7 ± 0.3 mg/g), representing a 2.03-fold increase relative to the Mn0 control group. This enhancement was primarily attributed to the activation of the terpenoid biosynthesis pathway, particularly through HMGS (3-hydroxy-3-methylglutaryl-CoA synthase) regulation by Mn²+. The heterologous expression of HMGS in Saccharomyces cerevisiae resulted in the overexpression strain Sc-HS1, which exhibited significantly higher squalene production compared to the Ck strain, regardless of the presence or absence of an inducer. Our findings highlight the critical role of HMGS in triterpenoid biosynthesis under Mn²+ treatment. These data provide a foundation for optimizing triterpenoids production, with potential applications in industrial-scale bioprocessing.

To investigate the effects and underlying mechanisms of sodium (Na⁺) on the growth characteristics of Sanghuangporus baumii mycelia, a single-factor Na⁺ addition experiment was performed. We found that treatment with 10 mmol/L Na⁺ (Na10) significantly increased the growth rate (0.41 ± 0.01 cm/d) and biomass (4.27 ± 0.05 g/L) of S. baumii mycelia, surpassing the control (Ck) group by 3.14% and 4.06%, respectively. In contrast, treatment with 100 mmol/L Na⁺ (Na100) resulted in a significant reduction in growth rate (0.34 ± 0.01 cm/d) and biomass (3.25 ± 0.02 g/L) of S. baumii mycelia compared to the Ck group. Transcriptome analysis further revealed that low Na⁺ concentrations (10 mmol/L) promoted the accumulation of soluble sugars (7.63 ± 0.54 mg/g) and upregulated the expression of pertinent genes, thereby accelerating mycelial growth. On the other hand, high Na⁺ concentrations (100 mmol/L) led to H₂O₂ accumulation (12.18 ± 0.24 μmol/g), causing toxicity in S. baumii mycelia. High Na⁺ concentrations also significantly boosted the production of valuable metabolites, such as triterpenoids (19.65 ± 0.22 mg/g), although the exact mechanisms remain to be elucidated. Overall, we suggest an effective approach for accelerating mycelial growth cycles and enhancing the production of high-value bioactive compounds from S. baumii.

Sanghuangporus baumii, a fungus used in traditional Chinese medicine, produces important pharmacological compounds such as triterpenoids, but at levels significantly lower than those required for medical use. This study investigated the effects of various concentrations of Ca²⁺ on S. baumii mycelial growth and the heterologous biosynthesis of S. baumii triterpenoids. Under induction by 10 mM Ca²⁺, the growth rate (0.39 cm/d) and biomass (4.48 g/L) of S. baumii mycelia were 1.03% and 10.05% higher than those in the 0 mM Ca²⁺-treatment group, respectively. In contrast, 200 mM Ca²⁺ significantly inhibited the growth rate and biomass of the mycelia. Notably, the total triterpenoid content reached its peak (17.71 mg/g) in the 200 mM Ca²⁺-treatment group, with a significant increase in the Ca²⁺ content (3869.97 µg/g) in the mycelia. Subsequently, the differential metabolic pathways and related genes between the S. baumii groups were examined using transcriptomic analysis. The results indicated that the increase in the growth rate and biomass of S. baumii mycelia was primarily due to elevated soluble sugar content, whereas the growth inhibition was associated with the toxic effects of H₂O₂. The observed differences in triterpenoid content were mainly attributed to the activation of the terpenoid backbone biosynthesis pathway and the AACT gene. Finally, the AACT gene was cloned and transformed into yeast cells, thus creating strain Sc-AA1. Upon treatment at the optimal Ca²⁺ concentration, the squalene content of strain Sc-AA1 reached 0.78 mg/g, 2.89-fold higher than that in the control group. These findings are significant for the heterologous biosynthesis of triterpenoids from S. baumii. Our study demonstrates the feasibility of producing triterpenoids in Saccharomyces cerevisiae and provides a foundation for future optimization toward achieving industrially relevant yields.

Background: Basic helix–loop–helix (bHLH) transcription factors (TFs) widely exist in eukaryotic organisms and play a key role in plant growth and development in response to environmental stresses. Sanghuangporus baumii, an important medicinal mushroom known for its anticancer properties, has limited research on the bHLH gene family. Methods: This research utilized the genomic data from S. baumii to identify bHLH family members, and their gene structure, conserved motifs, and phylogenetic relationship were characterized. Additionally, we conducted an analysis of promoter cis-elements and predicted protein interaction networks. We also examined the expression profiles of bHLH genes during different developmental stages and in response to four abiotic stresses: heat, cold, oxidative stress, and heavy metal exposure. Finally, we overexpressed the candidate gene SbbHLH3 in yeast to assess its tolerance to these different stress conditions. Results: A total of 12 SbbHLH genes were identified in S. baumii, and the members of the bHLH gene family displayed a variety of physicochemical characteristics, reflecting their diverse array of functions. Based on homology, the SbbHLH proteins are more closely related to those found in Lentinula edodes and Pleurotus ostreatus. The analysis of promoter cis-elements showed that SbbHLHs contain several elements associated with abiotic stress response, and a network prediction identified 28 bHLH-interacting proteins. Expression pattern analysis revealed that most SbbHLH genes exhibited a positive response to different developmental stages and abiotic stresses. Notably, the overexpression of SbbHLH3 significantly enhanced stress tolerance in yeast. Conclusions: This study provides a comprehensive assessment of the bHLH family in S. baumii, delivering new genetic resources for breeding resistant varieties.

Crepidotus subg. Dochmiopus contributes to more than half of Crepidotus species and exhibits highly hidden diversity. However, C. subg. Dochmiopus is challenging to study because the basidiomata of C. subg. Dochmiopus species are usually small and white, inconspicuous interspecific distinctions, and possess a familiar complex. In this study, we utilized a variety of characteristics for species identification, including habitat, presence or absence of a stipe in mature specimens, pileipellis and cheilocystidia patterns, whether the lamellae edges are fimbriated, and other characteristics. Above all, cheilocystidia and pileipellis patterns will be important in C. subg. Dochmiopus research. Based on the present specimens, we constructed a multigene phylogenetic tree (ITS + LSU) and recognized four new species: C. lamellomaculatus sp. nov., C. capitatocystidiatus sp. nov., C. succineus sp. nov., C. clavocystidiatustustus sp. nov. Detailed morphological descriptions, photographs, line drawings and comparisons with closely related taxa for the new species are provided. The current phylogenetic analysis does not support the previously classifications, indicating that the classification of Crepidotus requires re-evaluation. But the existing molecular datasets and species’ descriptions are insufficient to fully resolve the classification. Further integration of new gene segments and a comprehensive review of morphological characteristics will reveal a natural classification for Crepidotus.

Triterpenoids are secondary metabolites produced by the fungus Sanghuangporus baumii that have important pharmacological activities. However, the yield of triterpenoids is low and cannot meet market demand. Here, we treated S. baumii with several concentrations of MeJA (methyl jasmonate) and found that the total triterpenoid content was highest (23.31 mg/g) when the MeJA concentration was 250 μmol/L. qRT-PCR was used to quantify the transcription of five key genes involved in triterpenoid biosynthesis. The results showed that the relative transcription of most genes increased with increasing MeJA concentration, indicating that MeJA is a potent inducer of triterpenoid biosynthesis in S. baumii. To further explore whether other terpenoid biosynthesis pathways are also involved in the accumulation of triterpenoids induced by MeJA, we measured the contents of cis-Zeatin (cZ), gibberellins (GAs), and the transcript levels of related biosynthesis genes. We found that MeJA significantly inhibited the biosynthesis of cZ, GAs, and the transcription of related genes. The repressive effects of MeJA on cZ and GA accumulation were further confirmed by growth rate and biomass assays. In conclusion, our study provides an effective method to enhance the triterpenoid content of S. baumii, and also provides novel insights into the mechanism of MeJA-induced triterpenoid biosynthesis.

Sanghuangporus baumii is a traditional medicinal fungus that produces pharmacological terpenoids, but natural resources are insufficient for applications, and its growth and development mechanisms are poorly understood. Combining metabolomic and transcriptomic analyses, we found four terpenoid hormones and a central gene, isopentenyl diphosphate isomerase (IDI), involved in growth and development. Additionally, an exogenous hormone test was used to further confirm the importance of the four terpenoid hormones. Finally, hormone content determination and qRT−PCR were performed to explore the growth and development mechanism; we found thatcis-zeatin (CZ) plays a major role in the mycelia stage, trans-zeatin (TZ) and gibberellin A4 (GA4) are important in the primordia stage, GA4 is crucial for the fruiting bodies stage, and abscisic acid (ABA) may be a marker of maturity. The IDI gene was also found to affectterpenoid hormone content by regulating the relative gene transcript levels, thereby controlling morphological changes in S. baumii. Our results revealthe growth and development mechanisms of S. baumii and may promote the breeding and utilisation of high-quality varieties.