Xu Zhao

The rare edible and medicinal mushroom Floccularia luteovirens faces challenges from limited wild resources and low triterpenoid yield in submerged fermentation. To address this, we systematically optimized the fermentation medium using one-factor-at-a-time experiments combined with Response Surface Methodology (RSM). Wheat flour, peptone, and KH₂PO₄ were identified as the optimal carbon, nitrogen, and inorganic salt sources, respectively. Subsequently, we developed and validated distinct, highly predictive mathematical models for intracellular (R² = 0.9989) and extracellular (R² = 0.9984) triterpenoid production. This yielded two optimized media: one designed to maximize intracellular accumulation (29.71 g/L wheat flour, 2.03 g/L peptone, 1.02 g/L KH₂PO₄), achieving a yield of 18.83 mg/g, and another tailored for high extracellular secretion (30.28 g/L wheat flour, 2.08 g/L peptone, 1.05 g/L KH₂PO₄), achieving a titer of 0.63 g/L. The experimental results for both targets closely matched the model predictions. Thus, this study not only significantly enhanced overall triterpenoid production but also delineated nutrient-specific strategies for targeting different product locales. The findings provide a reliable technical and theoretical foundation for the scalable and sustainable production of these bioactive compounds.

Floccularia luteovirens is an edible and medicinal fungus with great development value on the Qinghai–Tibet Plateau, but its artificial domestication and cultivation are limited by the lack of systematic research on cultivation substrate formulas and key parameters. This study adopted the technical route of “preliminary screening—single-factor optimization—response surface collaborative optimization” to conduct research on the screening and optimization of its domestication cultivation substrate. Firstly, through the preliminary screening of 26 groups of formulas, a basic cultivation substrate formula with compatible complex nutrition and physical structure was determined. Secondly, single-factor experiments clarified that mixed sawdust was the optimal main substrate, corn flour was the optimal auxiliary substrate, the suitable substrate-to-water ratio was 1:1.6, and the suitable compactness was a substrate surface height of 12–12.5 cm (corresponding to a bulk density of 1.10–1.15 g/cm³ and a porosity of 60.6–63.3%). Finally, based on the response surface Box–Behnken model, with the main substrate, substrate-to-water ratio, and compactness as independent variables, and the total mycelial growth in 30 days as the response value, response surface optimization was performed to obtain the optimal formula: main substrate 76.002%, substrate-to-water ratio 1:1.721, and compactness 12.845 cm. Under these conditions, the mycelial growth reached 28.75 mm, which was highly consistent with the model’s predicted value (28.012 mm), and the constructed quadratic regression model showed excellent fitness (R² = 0.9920, p = 0.0008). This study clarified the core influencing factors and adaptation mechanism of the cultivation substrate for Floccularia luteovirens, filled the research gap in the domestication cultivation substrate of this fungus, and provided basic technical parameters for its large-scale artificial cultivation.

Floccularia luteovirens is a rare and edible fungus endemic to the Qinghai–Tibet Plateau. Traditional viewpoints have inferred it to be a mycorrhizal fungus based on its spatial association with Kobresia, yet direct morphological evidence (e.g., Hartig net) and molecular evidence is lacking. Through a systematic review of the existing literature, this study found that all current evidence supporting a mycorrhizal relationship is merely indirect inference. In contrast, experiments conducted by our research team demonstrated that this fungus colonizes well on sawdust-based substrates, which is compatible with saprobic growth capacity and does not exclude the possibility of conditional mycorrhizal symbiosis in natural environments. Based on these findings, we propose that F. luteovirens may adopt a facultative nutritional mode to adapt to the alpine environment. Genomic analysis revealed that the CAZyme repertoire of F. luteovirens (including key enzyme families such as GH6, GH7, and AA1) shows high similarity to that of the saprobic fungus Agaricus bisporus and appears to be more comprehensive than that of the ectomycorrhizal fungus Boletus edulis, based on current annotation data. This pattern suggests its potential capacity for lignocellulose degradation. The successful cultivation of its closely related species Lepista sordida on various lignocellulosic substrates further supports this functional potential. This study proposes that F. luteovirens employs a ‘facultative nutrition’ strategy, which presents an alternative perspective to the traditional view of obligate dependence on mycorrhizal symbiosis. These findings contribute to our understanding of fungal adaptation in alpine environments and may inform strategies for artificial domestication of this valuable species.

Floccularia luteovirens is a rare edible and medicinal fungus endemic to the Qinghai–Tibet Plateau, prized for its abundance of high-value bioactive metabolites such as polysaccharides, terpenoids, and ergothioneine, which exhibit a variety of biological activities including immunomodulatory, antioxidant, and antitumor effects. Due to the current lack of successful domestication and limited wild resources, liquid fermentation technology has become an important strategy for the large-scale production of its mycelium and bioactive components. This review systematically summarizes the biological characteristics of F. luteovirens, the diversity of its metabolites, biosynthetic pathways, regulatory mechanisms influenced by environmental factors, and the application of multi-omics technologies in related research. It is suggested that future studies should integrate multi-omics approaches to elucidate its stress response and metabolic regulatory networks, and achieve high-value utilization of this resource through stress-resistant breeding and optimization of fermentation processes.

Edible and medicinal fungi are a general term for large fungi with both edible and medicinal values. As a unique wild edible and medicinal fungus in the Qinghai-Tibet Plateau, the ‘Four Medical Classics’ of the Tang Dynasty has recorded Floccularia luteovirens effects of external application and internal administration on swelling, cold disease, and neck stiffness. At present, it has not been artificially domesticated and has significant development potential. The mushroom is rich in nutrients. The crude protein content of 100 g dried product is 33~39% (up to 38.71 g, about 2.2 times that of Flammulina velutipes). It contains 19 amino acids (including 8 essential amino acids for the human body; tryptophan accounts for 21.55~22.63%). It is also rich in minerals such as selenium, zinc (0.09 g/kg), and iron (0.3 g/kg) and vitamins B1 (0.10 mg), B2 (1.10 mg), C (4.50 mg), and E (6.20 mg). Among the functional active substances, polysaccharides (containing 20.1% β-glucan and 5.7% mannan-oligosaccharide) had antioxidant and immunomodulatory effects, which could alleviate the weight loss of diabetic rats. The IC50 of DPPH free radical scavenging rate of phenolics (ferulic acid, etc.; total phenolic content of 4.21 ± 0.06 mg/g) was 43.85 μg/mL; there was also adenosine, volatile oil, and other components. Pharmacologically, the DPPH free radical scavenging rate of the extract was 65 ± 0.46%, the tumor inhibition rate of the polysaccharide on the tumor-bearing mice was 42.48%, the gastrodin was biocatalyzed (conversion rate 85.2%), and the extracellular polysaccharide could inhibit the color change in shrimp to achieve preservation. This paper reviews its related research progress and provides a reference for its development in the fields of healthy food and biomedicine.

To comprehensively investigate the physiological characteristics and metabolic processes of the mycelium of Floccularia luteovirens (F. luteovirens), a wild edible fungus unique to the plateau region, we conducted an in-depth analysis of the mycelium enzyme activity and metabolites during different culture periods. The activity of seven enzymes all followed a trend of initially increasing and then decreasing. The intra- and extracellular activity peaks of three hydrolases—amylase, protease, and cellulase—all occurred on the 20th day, except for the extracellular amylase, which peaked on the 15th day. In contrast, the peak activity of laccase occurred on the 10th day. Moreover, three types of oxidoreductases in the mycelium (catalase (CAT), superoxide dismutase (SOD), and 2,3,5-triphenyltetrazolium chloride (TTC)-dehydrogenase (TTC-DH)) also exhibited significant changes in activity. CAT and SOD activity reached their maximum on the 20th day, whereas TTC-DH showed high activity on both the 10th and 20th days. Through a comprehensive assessment of the evolving trends of these physiological parameters, we determined that the optimal cultivation cycle for F. luteovirens liquid spawn is 20 days. An untargeted metabolomic analysis revealed that 3569 metabolites were detected in the F. luteovirens mycelium, including a variety of secondary metabolites and functional components, with terpenoids being particularly abundant, accounting for 148 types. By comparing three different culture stages (10 days, 20 days, and 30 days), 299, 291, and 381 metabolites, respectively, showed different accumulation patterns in the comparison groups of 10d vs. 20d, 20d vs. 30d, and 10d vs. 30d. These differential metabolites were primarily concentrated in carboxylic acids and their derivatives, fatty acyl groups, organic oxygen compounds, and lipid compounds. In addition, there were several amino acids whose abundance continued to grow during culturing. The metabolism of amino acids greatly affects mycelium growth and development. This research delineates the interplay between mycelium growth and metabolism, offering empirical support for a cultivation strategy for liquid F. luteovirens, and an exploration of its metabolites for potential applications.

Through whole-genome re-sequencing of 18 Hymenopellis radicata germplasm resources collected from diverse regions in China, we identified significant variations in the form of Single Nucleotide Polymorphisms (SNPs) and Insertions and Deletions (InDels). These variations were comprehensively annotated, shedding light on the mutation types present in the entire genome of the H. radicata germplasm. This analysis revealed the number and position information of each mutation and provided insights into the overall genomic landscape of H. radicata germplasm. Utilizing SNP data, we delved into the population structure of the 18 H. radicata germplasm resources. The results indicated the presence of 2,335,179 Indel sites and 12,050,448 SNP sites. The population structure analysis unveiled two distinct subgroups among the H. radicata germplasm resources. Phenotypic statistics, principal component analysis, and phylogenetic tree results echoed the findings of the population structure analysis. Different strains of H. radicata from various regions in China exhibited notable differences in genetic diversity, mycelial growth rate, yield, and fruiting body characteristics. Significant disparities were observed between the two subgroups, while strains within each subgroup shared common characteristics. This research establishes a solid foundation for integrating H. radicata into diverse breeding programs. The data underscore the potential of H. radicata for genetic improvement and exploitation in breeding initiatives, paving the way for future advancements in this field.

Floccularia luteovirens, a rare wild edible and medicinal fungus, is endemic to the Tibetan plateau. However, attempts to artificially domesticate this species have not been successful, resulting in extremely limited utilization of this valuable resource. This paper presents the geographical distribution of F. luteovirens, along with its ecological and biological characteristics. It explores population relations, symbiotic relationships, soil microbial community relations, fruiting body occurrence conditions, nutritional metabolism, and reproductive patterns. The cultivation techniques, as well as the edible and medicinal value of this mushroom, are also reviewed. Through an overall analysis of the physiological characteristics and current research status of F. luteovirens, the paper discusses its development prospects. The aim is to provide a reference for other researchers and promote its artificial domestication, resource development, and utilization.