In this work, methyl jasmonate (MeJA), as an exogenous elicitor, was used to investigate the feasibility of enhancing triterpenoid biosynthesis in Inonotus baumii. The results showed that the appropriate concentration of MeJA to be added was 150 μmol/L, and the triterpenoid yield was 12.61 mg/g dry weight (DW), which was 4.05-fold higher than that in the control with water. Moreover, quantitative real-time polymerase chain reaction was performed to measure the transcript levels of several genes in the triterpenoid pathway, including those encoding hydroxy-3-methylglutaryl-Coenzyme A synthase (hmgs), hydroxy-3-methylglutaryl-Coenzyme A reductase (hmgr), farnesyl pyrophosphate synthase (fpps), squalene synthase (sqs), squalene epoxidase (se) and lanosterol synthase (ls). The results demonstrated that these genes were mostly up-regulated by MeJA, although the levels of induction differed. For hmgs, hmgr, fpps and se, the highest transcript levels were at 150 μmol/L MeJA, and were approximately 3.0, 2.5, 2.0 and 2.0-fold higher than those in the control, respectively. However, the sqs and ls genes appeared to be repressed by MeJA. To the best of our knowledge, this is the first time to assess the use of MeJA to elicit triterpenoid biosynthesis in I. baumii, and the results indicated that MeJA was indeed a potent inducer of 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.

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.

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.

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.

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.