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.

Lentinula edodes (L. edodes), one of the most popular edible mushrooms in China, is adversely affected by high temperature. Heat shock proteins (HSPs) play a crucial role in regulating the defense responses against the abiotic stresses in L. edodes. Some HSPs in L. edodes have been described previously, but a genome-wide analysis of these proteins is still lacking. Here, the HSP genes across the entire genome of the L. edodes mushroom were identified. The 34 LeHSP genes were subsequently classified into six subfamilies according to their molecular weights and the phylogenetic analysis. Sequence analysis showed that LeHSP proteins from the same subfamily have conserved domains and one to five similar motifs. Except for Chr 5 and 9, 34 LeHSPs genes were distributed on the other eight chromosomes. Three pairs of paralogs were identified because of sequence alignment and were confirmed as arising from segmental duplication. In LeHSPs’ promoters, different numbers of heat shock elements (HSEs) were predicted. The expression profiles of LeHSPs in 18N44 and 18 suggested that the thermo-tolerance of strain 18N44 might be related to high levels of LeHSPs transcript in response to heat stress. The quantitative real-time PCR (qRT-PCR) analysis of the 16 LeHSP genes in strains Le015 and Le027 verified their stress-inducible expression patterns under heat stress. Therefore, these comprehensive findings provide useful in-depth information on the evolution and function of LeHSPs and lay a theoretical foundation in breeding thermotolerant L. edodes varieties.

Floccularia luteovirens is one of the rare edible fungi with high nutritional value found on the Qinghai-Tibet Plateau. However, research at the molecular level on this species is currently constrained due to the lack of reliable reference genes for this species. Thirteen potential reference genes (ACT, GAPDH, EF-Tu, SAMDC, UBI, CLN1, β-TUB, γ-TUB, GTP, H3, UBC, UBC-E2, and GTPBP1) were chosen for the present study, and their expression under various abiotic conditions was investigated. Stability of gene expression was tested using GeNorm, NormFinder, BestKeeper, Delta-Ct, and RefFinder. The results showed that the most suitable reference genes for salt treatment were ACT and EF-Tu. Under drought stress, γ-TUB and UBC-E2 would be suitable for normalization. Under oxidative stress, the reference genes H3 and GAPDH worked well. Under heat stress, the reference genes EF-Tu and γ-TUB were suggested. Under extreme pH stress, UBC-E2 and H3 were appropriate reference genes. Under cadmium stress, the reference genes ACT and UBC-E2 functioned well. In different tissues, H3 and GTPBP1 were appropriate reference genes. The optimal internal reference genes when analyzing all samples were H3 and SAMDC. The expression level of HSP90 was studied to further validate the applicability of the genes identified in this study.

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.

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.

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.