Comparative Analysis of Agronomic Traits, Yield, and Effective Components of Main Cultivated Ganoderma Mushrooms (Agaricomycetes) in China.

To assess the strain resources and address production challenges in Ganoderma cultivation. 150 Ganoderma strains were collected from 13 provinces in China. A comparative analysis of agronomic traits and effective components was conducted. Among the 150 strains, key agronomic traits measured were: average stipe diameter (15.92 mm), average stipe length (37.46 mm), average cap horizontal diameter (94.97 mm), average cap vertical diameter (64.21 mm), average cap thickness (15.22 mm), and average fruiting body weight (14.30 g). Based on these agronomic traits, four promising strains, namely, L08, L12, Z21, and Z39, were recommended for further cultivation and breeding. The average crude polysaccharide content ranged from 0.048% to 0.977%, and triterpenoids ranged from 0.804% to 2.010%. In addition, 73 triterpenoid compounds were identified, constituting 47.1% of the total compounds. Using a distance discrimination method, the types, and relative contents of triterpenoid compounds in 150 Ganoderma strains were classified, achieving 98% accuracy in G. lingzhi identification. The 16 triterpenoid components used for G. lingzhi identification included oleanolic acid, ursolic acid, 3ß-acetoxyergosta-7,22-dien-5α-ol, ganoderic acid DM, ganoderiol B, ganorderol A, ganoderic acid GS-1, tsugaric acid A, ganoderic acid GS-2, ganoderenic acid D, ganoderic acid Mf, ganoderic acid A, ganoderic acid K, ganoderic acid V, ganoderic acid G, and leucocontextin J. This study provides valuable insights for exploring and utilizing Ganoderma resources and for the development of new varieties.

Population genetics provides insights into the important agronomic traits of Ganoderma cultivation varieties in China.

This study aimed to investigate the species diversity and genetic differentiation of the genome of the main cultivated strains of Ganoderma in China. Population genomics analysis was conducted based on 150 cultivated strains of Ganoderma collected nationwide. The results indicated that the main species currently cultivated in China were Ganoderma sichuanense and Ganoderma lucidum, with a minor proportion of Ganoderma sessile, Ganoderma weberianum, Ganoderma sinense, Ganoderma gibbosum and Ganoderma australe. A total of 336,506 high-quality single nucleotide polymorphism (SNP) loci were obtained through population evolution analysis. The Fst values were calculated using a 5-kb sliding window, which ranged from 0.11 to 0.74. This suggests varying degrees of genetic differentiation between populations and genetic exchange among varieties. On this basis, the genes related to the stipe length, cap color and branch phenotypes of Ganoderma were excavated, and the region with the top 1% ZFst value region was used as a candidate region. A total of 137, 270 and 222 candidate genes were identified in the aforementioned 3 phenotypes, respectively. Gene annotation revealed that genes associated with stipe length were mainly related to cell division and differentiation, including proteins such as Nse4 protein and DIM1 protein. The genes related to Ganoderma red color were mainly related to the metabolism of tryptophan and flavonoids. The genes related to the branch were mainly related to cytokinin synthesis, ABC transporter and cytochrome P450. This study provided 150 valuable genome resequencing data in assessing the diversity and genetic differentiation of Ganoderma and laid a foundation for agronomic trait analysis and the development of new varieties of Ganoderma.

Study on Characteristics of Triterpenoids and Hepatoprotective Effects of Fruit Body of Stout Camphor Mushroom, Taiwanofungus camphoratus (Agaricomycetes), Cultivated with Apple-Wood.

Taiwanofungus camphoratus is a parasite medicinal fungus with significant hepatoprotective activity that grows in Cinnamomum camphora, a class II protected tree species in Taiwan. Currently, commercial cultivation of T. camphoratus is limited by the resources of C. camphora. To broaden the range of substrates, this study investigated the feasibility of using apple-wood as a substrate for T. camphoratus cultivation and examined the content of fruit body triterpenoids and liver-protective activity as quality indicators. The triterpenoids were determined by ultra-performance liquid chromatography-mass spectrometry and compared with T. camphoratus cultivated in C. camphora. The ICR mouse acute alcoholic liver injury model was used to explore the hepatoprotective effects of the apple-wood cultivated fungus. T. camphoratus grew on apple-wood medium within 7 months; a total of 62 fungal triterpenoid components were detected, including the seven characteristic triterpenoids. Only three were higher in T. camphoratus cultured on C. camphora. The medium-dose fungal extracts (150 mg/kg) produced significant protective effects against acute alcoholic liver injury in mice. These results indicate that apple-wood cultivation is a feasible method compared to C. camphora for commercial cultivation of T. camphoratus.

Preliminary Studies on the Effects of Oyster Mushroom Spherical Virus China Strain on the Mycelial Growth and Fruiting Body Yield of the Edible Mushroom Pleurotus ostreatus.

Oyster mushroom spherical virus (OMSV) is a positive-sense single-stranded RNA mycovirus which is associated with a devastating oyster mushroom die-back disease. However, little is known about its diversity, and the effects of OMSV infection on its fungal host are not well understood. In this study, we determined the nearly complete nucleotide sequence of OMSV isolated from cultivated oyster mushrooms in China. Sequence analysis suggested that the virus represents a new strain of OMSV (referred to here as OMSV-Ch). A GenBank BLAST search of the genomic sequences demonstrated that the OMSV-Ch had the highest identity (74.9%) with the OMSV from Korea (OMSV-Kr). At the amino acid-sequence level, these two strains shared 84.1% identity in putative replication protein (RP) and 94.1% identity in coat protein (CP). Phylogenetic analysis based on RP showed that OMSV-Ch clustered with OMSV-Kr, closely related to Tymoviridae. Phylogenetic analysis based on both the RP and CP showed that OMSV had a distant clade relationship with tymoviruses, marafiviruses, and maculaviruses. We obtained the OMSV-Ch-free Pleurotus ostreatus strain via single hyphal tip cultures combined with high-temperature treatment. Preliminary studies indicate that OMSV-Ch can significantly inhibit mycelial growth, cause malformations of the fruiting bodies, and reduce the yield of P. ostreatus. Co-cultivation resulted in horizontal transmission of the OMSV-Ch to a virus-cured strain. The findings of our study contribute to the prevention and control of mycoviral diseases in the future.

New Species of Talaromyces (Fungi) Isolated from Soil in Southwestern China.

Southwestern China belongs among the global biodiversity hotspots and the Daba Mountains are recognized as one of the priority conservation areas. During the exploration of fungal biodiversity from soil samples collected from Mount Daba, two species of Talaromyces were discovered as new to science based on phylogenetic analyses and morphological comparisons. Talaromyces chongqingensis sp. nov. is a sister taxon of T. minioluteus and T. minnesotensis in the section Trachyspermi; and T. wushanicus sp. nov., affiliated to the section Talaromyces, is closely related to T. cnidii and T. siamensis. The new species differ from their sisters in DNA sequences, growth rates, and morphological characteristics. Descriptions and illustrations of them are provided in detail.

DNA Barcoding Mushroom Spawn Using EF-1α Barcodes: A Case Study in Oyster Mushrooms (Pleurotus).

Oyster mushrooms (genus Pleurotus) are widespread and comprise the most commonly cultivated edible mushrooms in the world. Species identification of oyster mushroom spawn based on cultural, morphological, and cultivated characteristics is time consuming and can be extraordinarily difficult, which has impeded mushroom breeding and caused economic loss for mushroom growers. To explore a precise and concise approach for species identification, the nuclear ribosomal internal transcribed spacer (ITS), 28S rDNA, and the widely used protein-coding marker translation elongation factor 1α (EF-1α) gene were evaluated as candidate DNA barcode markers to investigate their feasibility in identifying 13 oyster mushroom species. A total of 160 sequences of the candidate loci were analyzed. Intra- and interspecific divergences and the ease of nucleotide sequence acquisition were the criteria used to evaluate the candidate genes. EF-1α showed the best intra- and interspecific variation among the candidate markers and discriminated 84.6% of the species tested, only being unable to distinguish two closely related species Pleurotus citrinopileatus and Pleurotus cornucopiae. Furthermore, EF-1α was more likely to be acquired than ITS or 28S rDNA, with an 84% success rate of PCR amplification and sequencing. For ITS and 28S rDNA, the intraspecific differences of several species were distinctly larger than the interspecific differences, and the species identification efficiency of the two candidate markers was worse (61.5 and 46.2%, respectively). In addition, these markers had some sequencing problems, with 55 and 76% success rates of sequencing, respectively. Hence, we propose EF-1α as a possible DNA barcode marker for oyster mushroom spawn.

Overexpression of the NDR1/HIN1-Like Gene NHL6 Modifies Seed Germination in Response to Abscisic Acid and Abiotic Stresses in Arabidopsis.

NHL (NDR1/HIN1-like) genes play crucial roles in pathogen induced plant responses to biotic stress. Here, we report the possible function of NHL6 in plant response to abscisic acid (ABA) and abiotic stress. NHL6 was highly expressed in non-germinated seeds, and its expression was strongly induced by ABA and multiple abiotic stress signals. Loss-of-function of NHL6 decreased sensitivity to ABA in the early developmental stages including seed germination and post-germination seedling growth of the nhl6 mutants. However, overexpression of NHL6 increased sensitivity to ABA, salt and osmotic stress of the transgenic plants. Further studies indicated that the increased sensitivity in the 35S::NHL6 overexpressing plants could be a result of both ABA hypersensitivity and increased endogenous ABA accumulation under the stress conditions. It was also seen that the ABA-responsive element binding factors AREB1, AREB2 and ABF3 could regulate NHL6 expression at transcriptional level. Our results indicate that NHL6 plays an important role in the abiotic stresses-induced ABA signaling and biosynthesis, particularly during seed germination and early seedling development in Arabidopsis.

Analysis of genetic diversity among Chinese Pleurotus citrinopileatus Singer cultivars using two molecular marker systems (ISSRs and SRAPs) and morphological traits.

To evaluate the genetic diversity of Pleurotus citrinopileatus Singer cultivars in China, 20 P. citrinopileatus strains were analyzed using morphological traits, inter-simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) molecular markers. Eleven ISSR primers amplified a total of 116 DNA fragments of which 96 (82.91%) were polymorphic, whereas 8 SRAP primer pairs amplified 69 fragments of which 65 (93.47%) were polymorphic. Phylogenetic trees constructed on the basis of ISSR, SRAP, and combined ISSR/SRAP analyses using the Unweighted Pair-group Method with Arithmetic Averages method distributed the 20 strains into three or six major groups. The grouping exhibited great similarity and was generally consistent with their morphological characters and antagonism test, which indicated a high level of genetic diversity among P. citrinopileatus Singer and relationship between each other. Based on the genetic analysis, the primary mini-core strains were constructed with progressive sampling method of the smallest genetic distance. The mini-core germplasm collection included 4 strains (strain 2, 5, 7 and 11). Our findings will provide a scientific fundament for facilitating parent selection for broadening genetic base, accelerating the genetic breeding, identification of cultivated strains and the development of bioactive products from this commercially important medicinal mushroom.

[Optimization of submerged culture condition for production of mycelial biomass by Armillaria mellea].

OBJECTIVE: To optimize the submerged culture conditions for the production of mycelial biomass by Amillaria mellea. METHODS: Using the statistically based experimental design in a shake flask culture, optimum concentration of each medium component was determined using the statistical method. RESULTS: Dextrin was the suitable carbon source, bean cake extract was the suitable nitrogen source. Both corn steep liquor and thiamin favored the mycelial growth. Ethanol also favored the mycelial growth. (NH4 )2SO4 and NaNO3 inhibited mycelial growth whereas KH2PO4 favored the mycelial growth. CONCLUSION: The optimal combination of the media concentrations for mycelial growth was as follows: bean cake extract 25%, corn steep liquor 2%, dextrin 2.5%, thiamin 0.06%, ethanol 1.0%, KH2PO4 0.3%, pH 6.0. Under the optimal culture condition, the production of mycelial biomass achieved 1.9g/100ml.

[Cultural characteristics of Armillaria mellea on solid media].

OBJECTIVE: To study the cultural characteristics of Armillaria mellea (A. mellea ) on solid media. METHODS: A. mellea was cultured on semi-solid agar medium in dark conditions. Effects of different media, carbon sources, nitrogen sources, and temperature on growth and morphology of A. mellea were observed. The contents of polysaccharide, mannitol, glucose, and reducing sugars in A. mellea during different stages of development were determined. RESULTS: The biomass and morphology of A. mellea were different in various media. Sugars were more effective carbon sources than the relevant sugar alcohols. Little molecular carbon sources such as alcohol and glycerol could be utilized by A. mellea, but starch only could be utilized slowly. Either organic or inorganic nitrogen sources could be uptaken and utilized effectively by A. mellea. No evidence was found that VitB1 affects the growth of A. mellea. The growth cycle on wort medium at 30 degrees C was shorter than that at 25 degrees C for 7 days. In logarithmic growth phase and stable phase, the polysaccharide contents of A. mellea were 9.24% and 4.70% respectively, while the mannitol contents were 10.08% and 10.58% respectively; glucose and reducing sugar contents remained low level in the whole growth stage. CONCLUSIONS: Carbon sources have a more remarked effect on the growth of A. mellea than the nitrogen sources do. Optimal temperature for the growth of A. mellea ranges 20-30 degrees C. Mannitol accumulates more than other little molecular carbohydrates in A. mellea.