Basidiomycete Research Articles

Mating-Type Locus Organization and Mating-Type Chromosome Differentiation in the Bipolar Edible Button Mushroom Agaricus bisporus.

In heterothallic basidiomycete fungi, sexual compatibility is restricted by mating types, typically controlled by two loci: PR, encoding pheromone precursors and pheromone receptors, and HD, encoding two types of homeodomain transcription factors. We analysed the single mating-type locus of the commercial button mushroom variety, Agaricus bisporus var. bisporus, and of the related variety burnettii. We identified the location of the mating-type locus using genetic map and genome information, corresponding to the HD locus, the PR locus having lost its mating-type role. We found the mip1 and β-fg genes flanking the HD genes as in several Agaricomycetes, two copies of the β-fg gene, an additional HD2 copy in the reference genome of A. bisporus var. bisporus and an additional HD1 copy in the reference genome of A. bisporus var. burnettii. We detected a 140 kb-long inversion between mating types in an A. bisporus var. burnettii heterokaryon, trapping the HD genes, the mip1 gene and fragments of additional genes. The two varieties had islands of transposable elements at the mating-type locus, spanning 35 kb in the A. bisporus var. burnettii reference genome. Linkage analyses showed a region with low recombination in the mating-type locus region in the A. bisporus var. burnettii variety. We found high differentiation between β-fg alleles in both varieties, indicating an ancient event of recombination suppression, followed more recently by a suppression of recombination at the mip1 gene through the inversion in A. bisporus var. burnettii and a suppression of recombination across whole chromosomes in A. bisporus var. bisporus, constituting stepwise recombination suppression as in many other mating-type chromosomes and sex chromosomes.

Direct Ethanol Production from Xylan and Acorn Using the Starch-Fermenting Basidiomycete Fungus Phlebia acerina

During our search for ethanol-producing basidiomycete fungi for a wide range of substrates, we isolated Phlebia acerina, which is a white rot basidiomycete fungus. It favorably converted starch into ethanol with approximately 70% yield. Although the yield decreased as the starch concentration increased, growth and fermentation were observed even at 200 g/L of starch. P. acerina produced ethanol from glucose, galactose, mannose, xylose, cellobiose, and maltose with 93%, 91%, 86%, 72%, 92%, and 68% yields, respectively. Additionally, P. acerina, which secreted xylanase and xylosidase, was capable of assimilating xylan and directly converting it to ethanol with a yield of 63%. Furthermore, P. acerina produced ethanol directly from acorns, which are plant fruits containing starch and tannins, with a yield of 70%. Tannin delayed mycelia growth, thus prolonging ethanol production; however, this did not particularly affect the yield. These results were similar to those of fermentation in a medium with the same amounts of starch and tannin as the target crop acorn, thus suggesting that P. acerina could successfully produce environmentally friendly ethanol from starch-containing lignocellulosic biomass, unlike previously reported ethanol-producing basidiomycete fungi.

Symbiotic nitrogen fixation in the reproductive structures of a basidiomycete fungus

Nitrogen (N) fixation is a driving force for the formation of symbiotic associations between N2-fixing bacteria and eukaryotes.1 Limited examples of these associations are known in fungi, and none with sexual structures of non-lichenized species.2-6 The basidiomycete Guyanagaster necrorhizus is a sequestrate fungus endemic to the Guiana Shield.7 Like the root rot-causing species in its sister genera Armillaria and Desarmillaria, G.necrorhizus sporocarps fruit from roots of decaying trees (Figures 1A-1C),8 and genome sequencing is consistent with observations that G.necrorhizus is a white-rotting decomposer. This species also represents the first documentation of an arthropod-dispersed sequestrate fungus. Numerous species of distantly related wood-feeding termites, which scavenge for N-rich food, feed on the mature spore-bearing tissue, or gleba, of G.necrorhizus. During feeding, mature spores adhere to termites for subsequent dispersal.9 Using chemical assays, isotope analysis, and high-throughput sequencing, we show that the sporocarps harbor actively N2-fixing Enterobacteriaceae species and that the N content within fungal tissue increases with maturation. Untargeted proteomic profiling suggests that ATP generation in the gleba is accomplished via fermentation. The use of fermentation-an anaerobic process-indicates that the sporocarp environment is anoxic, likely an adaptation to protect the oxygen-sensitive nitrogenase enzyme. Sporocarps also have a thick outer covering, possibly to limit oxygen diffusion. The enriched N content within mature sporocarps may offer a dietary inducement for termites in exchange for spore dispersal. These results show that the flexible metabolic capacity of fungi may facilitate N2-fixing associations, as well as higher-level organismal associations.

Preface

The 2nd International Conference on Sustainable Development and Environmental Science (ICSDES2021) was held on June 18-20, 2021 as a virtual conference due to the growing concerns over the coronavirus outbreak (COVID-19), and in order to protect the well-being of our attendees, partners, and staff as our number one priority. ICSDES2021 was organized by Academic Exchange Information Center. The aim of the conference is to provide a platform for researchers, engineers and students from industries and universities to exchange their ideas and technologies on Sustainable Development and Environmental Science.This scientific event brings together more than 60 national and international researchers in related research area. On top of the local participants coming from different national universities, international participants are also registered from different countries, namely Singapore, Malaysia, Norway and Nigeria. During the conference, the conference model was divided into three sessions, including oral presentations, keynote speeches, and online Q&A discussion. In the first part, some scholars, whose submissions were selected as the excellent papers, were given about 5-10 minutes to perform their oral presentations one by one. Then in the second part, keynote speakers were each allocated 30-45 minutes to hold their speeches.In the second part, we invited five professors as our keynote speakers. Prof. Shuntian Qiu, from School of Environmental Science and Engineering, Tianjin University, China, performed a speech: Integrated modelling of urban development and environmental pollution. And then we had Prof. Ying Feng, from Zhejiang University, China. She presented an insightful speech: The interaction mechanism between endophytic microorganisms and hyperaccumulators. Prof. Chunfeng Song, from School of Environmental Science and Engineering, Tianjin University, China. He delivered a wonderful speech: Green CO2 mitigation Strategy: Towards to a Carbon Neutral Future. In this speech, the status and development of current dominant CO2 capture and utilization techniques were presented. Prof. Caixia Chen, Department of Chemical Engineering for Energy, East China University of Science and Technology, China, performed a speech: A Comprehensive Two-fluid Model for Industrial Moving Grate MSW Incinerators. Our finale keynote speaker, A. Prof. Tony Hadibarata, from Curtin University, Sarawak, Malaysia. He presented an insightful speech: Biodegradation of polycyclic aromatic hydrocarbons by high - laccase basidiomycetes fungi isolated from tropical forest of Borneo. Their insightful speeches had triggered heated discussion in the third session of the conference. Every participant praised this conference for disseminating useful and insightful knowledge.The proceedings are a compilation of the accepted papers and represent an interesting outcome of the conference. Topics include but are not limited to the following areas: Environmental Chemistry, Environmental economics, Air pollution and control, Environment and health, Sustainable economy and more related topics. All the papers have been through rigorous review and process to meet the requirements of International publication standard.We would like to acknowledge all of those who supported ICSDES2021. The help and contribution of each individual and institution was instrumental in the success of the conference. In particular, we would like to thank the organizing committee for its valuable inputs in shaping the conference program and reviewing the submitted papers.List of Committee member, General Chair, Organizing Committees, TPC Chair, Technical Program Committees are available in this pdf.

Host Susceptibility Modulates Escovopsis Pathogenic Potential in the Fungiculture of Higher Attine Ants

Health and disease emerge from intricate interactions between genotypes, phenotypes, and environmental features. The outcomes of such interactions are context-dependent, existing as a dynamic continuum ranging from benefits to damage. In host-microbial interactions, both the host and environmental conditions modulate the pathogenic potential of a microorganism. Microbial interactions are the core of the agricultural systems of ants in the subtribe Attina, which cultivate basidiomycete fungi for food. The fungiculture environment harbors a diverse microbial community, including fungi in the genus Escovopsis that has been studied as damage-causing agent. Here, we consider the ant colony as a host and investigate to what extent its health impacts the dynamics and outcomes of host-Escovopsis interactions. We found that different ant fungal cultivars vary in susceptibility to the same Escovopsis strains in plate-assays interactions. In subcolony-Escovopsis interactions, while healthy subcolonies gradually recover from infection with different concentrations of Escovopsis conidia, insecticide-treated subcolonies evidenced traits of infection and died within 7 days. The opportunistic nature of Escovopsis infections indicates that diseases in attine fungiculture are a consequence of host susceptibility, rather than the effect of a single microbial agent. By addressing the host susceptibility as a major modulator of Escovopsis pathogenesis, our findings expand the understanding of disease dynamics within attine colonies.

Towards a Natural Classification of Hyphodontia Sensu Lato and the Trait Evolution of Basidiocarps within Hymenochaetales (Basidiomycota).

Hyphodontia sensu lato, belonging to Hymenochaetales, accommodates corticioid wood-inhabiting basidiomycetous fungi with resupinate basidiocarps and diverse hymenophoral characters. Species diversity of Hyphodontia sensu lato has been extensively explored worldwide, but in previous studies the six accepted genera in Hyphodontia sensu lato, viz. Fasciodontia, Hastodontia, Hyphodontia, Kneiffiella, Lyomyces and Xylodon were not all strongly supported from a phylogenetic perspective. Moreover, the relationships among these six genera in Hyphodontia sensu lato and other lineages within Hymenochaetales are not clear. In this study, we performed comprehensive phylogenetic analyses on the basis of multiple loci. For the first time, the independence of each of the six genera receives strong phylogenetic support. The six genera are separated in four clades within Hymenochaetales: Fasciodontia, Lyomyces and Xylodon are accepted as members of a previously known family Schizoporaceae, Kneiffiella and Hyphodontia are, respectively, placed in two monotypic families, viz. a previous name Chaetoporellaceae and a newly introduced name Hyphodontiaceae, and Hastodontia is considered to be a genus with an uncertain taxonomic position at the family rank within Hymenochaetales. The three families emerged between 61.51 and 195.87 million years ago. Compared to other families in the Hymenochaetales, these ages are more or less similar to those of Coltriciaceae, Hymenochaetaceae and Oxyporaceae, but much older than those of the two families Neoantrodiellaceae and Nigrofomitaceae. In regard to species, two, one, three and 10 species are newly described from Hyphodontia, Kneiffiella, Lyomyces and Xylodon, respectively. The taxonomic status of additional 30 species names from these four genera is briefly discussed; an epitype is designated for X. australis. The resupinate habit and poroid hymenophoral configuration were evaluated as the ancestral state of basidiocarps within Hymenochaetales. The resupinate habit mainly remains, while the hymenophoral configuration mainly evolves to the grandinioid-odontioid state and also back to the poroid state at the family level. Generally, a taxonomic framework for Hymenochaetales with an emphasis on members belonging to Hyphodontia sensu lato is constructed, and trait evolution of basidiocarps within Hymenochaetales is revealed accordingly.

Cytoplasmic Mixing, Not Nuclear Coexistence, Can Explain Somatic Incompatibility in Basidiomycetes.

Nonself recognition leading to somatic incompatibility (SI) is commonly used by mycologists to distinguish fungal individuals. Despite this, the process remains poorly understood in basidiomycetes as all current models of SI are based on genetic and molecular research in ascomycete fungi. Ascomycete fungi are mainly found in a monokaryotic stage, with a single type of haploid nuclei, and only briefly during mating do two genomes coexist in heterokaryotic cells. The sister phylum, Basidiomycota, differs in several relevant aspects. Basidiomycete fungi have an extended heterokaryotic stage, and SI is generally observed between heterokaryons instead of between homokaryons. Additionally, considerable nuclear migration occurs during a basidiomycete mating reaction, introducing a nucleus into a resident homokaryon with cytoplasmic mixing limited to the fused or neighboring cells. To accommodate these differences, we describe a basidiomycete model for nonself recognition using post-translational modification, based on a reader-writer system as found in other organisms. This post-translational modification combined with nuclear migration allows for the coexistence of two genomes in one individual while maintaining nonself recognition during all life stages. Somewhat surprisingly, this model predicts localized cell death during mating, which is consistent with previous observations but differs from the general assumptions of basidiomycete mating. This model will help guide future research into the mechanisms behind basidiomycete nonself recognition.

Genome reduction and relaxed selection is associated with the transition to symbiosis in the basidiomycete genus Podaxis

SummaryInsights into the genomic consequences of symbiosis for basidiomycete fungi associated with social insects remain sparse. Capitalizing on viability of spores from centuries-old herbarium specimens of free-living, facultative, and specialist termite-associated Podaxis fungi, we obtained genomes of 10 specimens, including two type species described by Linnaeus >240 years ago. We document that the transition to termite association was accompanied by significant reductions in genome size and gene content, accelerated evolution in protein-coding genes, and reduced functional capacities for oxidative stress responses and lignin degradation. Functional testing confirmed that termite specialists perform worse under oxidative stress, while all lineages retained some capacity to cleave lignin. Mitochondrial genomes of termite associates were significantly larger; possibly driven by smaller population sizes or reduced competition, supported by apparent loss of certain biosynthetic gene clusters. Our findings point to relaxed selection that mirrors genome traits observed among obligate endosymbiotic bacteria of many insects.

The Assembled and Annotated Genome of the Fairy-Ring Fungus Marasmius oreades.

Marasmius oreades is a basidiomycete fungus that grows in so called “fairy rings,” which are circular, underground mycelia common in lawns across temperate areas of the world. Fairy rings can be thought of as natural, long-term evolutionary experiments. As each ring has a common origin and expands radially outwards over many years, different sectors will independently accumulate mutations during growth. The genotype can be followed to the next generation, as mushrooms producing the sexual spores are formed seasonally at the edge of the ring. Here, we present new genomic data from 95 single-spore isolates of the species, which we used to construct a genetic linkage map and an updated version of the genome assembly. The 44-Mb assembly was anchored to 11 linkage groups, producing chromosome-length scaffolds. Gene annotation revealed 13,891 genes, 55% of which contained a pfam domain. The repetitive fraction of the genome was 22%, and dominated by retrotransposons and DNA elements of the KDZ and Plavaka groups. The level of assembly contiguity we present is so far rare in mushroom-forming fungi, and we expect studies of genomics, transposons, phylogenetics, and evolution to be facilitated by the data we present here of the iconic fairy-ring mushroom.

Enhanced polyethylene glycol (PEG)-mediated protoplast transformation system for the phytopathogenic fungus, Ganoderma boninense.

The basidiomycete fungus, Ganoderma boninense, has been identified as the main causal agent of oil palm basal stem rot (BSR) disease which has caused significant economic losses to the industry especially in Malaysia and Indonesia. Various efforts have been initiated to understand the disease and this plant pathogen especially at the molecular level. This is the first study of its kind on the development of a polyethylene glycol (PEG)-mediated protoplast transformation system for G. boninense. Based on the minimal inhibitory concentration study, 60µg/mL and above of hygromycin were effective to completely inhibit G. boninense growth. Approximately 5.145×107cells/mL of protoplasts with the viability of 97.24% was successfully obtained from G. boninense mycelium tissue. The PEG-mediated G. boninense protoplast transformation using 1µg of transformation vector, 25% of PEG solution, 10min of pre-transformation incubation, and 30min of post-transformation incubation has improved the transformation rate as compared with the previous reported protocols for other basidiomycete fungi. Optimization of four transformation parameters has improved the transformation efficiency of G. boninense from an average of 2 to 67 putative transformants. The presence of hygromycin phosphotransferase (hpt) and enhanced green fluorescent protein (eGFP) genes in the putative transformants was detected by PCR and verified by gene sequence analysis. Southern hybridization result further confirmed the integration of hpt gene in G. boninense transformants, and the green fluorescent signal was detected in the G. boninense transformants under the microscopic analysis. The establishment of this transformation system will accelerate the gene function studies of G. boninense especially those genes that may contribute to the pathogenesis of this fungus in oil palm.

Consoramides A–C, New Zwitterionic Alkaloids from the Fungus Irpex consors

In our ongoing search for new secondary metabolites from fungi, a basidiomycete fungus Irpex consors was selected for mycochemical investigation, and three new zwitterionic alkaloids (1-3) and five known compounds (4-8) were isolated from the culture broth (16 l) of I. consors. The culture filtrate was fractionated by a series of column chromatography including Diaion HP-20, silica gel, and Sephadex LH-20, Sep-Pak C18 cartridge, medium pressure liquid chromatography (MPLC), and high pressure liquid chromatography (HPLC) to yield eight compounds (1-8). The structures of the isolated compounds were elucidated by the interpretation of nuclear magnetic resonance (NMR) spectra and high-resolution mass spectrometry (HR-MS). Their antioxidant and antibacterial activities were examined. The zwitterionic structures of three new sesquiterpene alkaloids (1-3) were determined together with five known compounds identified as stereumamide E (4), stereumamide G (5), stereumamide H (6), stereumamide D (7), and sterostrein H (8). This is the first report of the zwitterionic alkaloids in the culture broth of I. consors. Three new zwitterionic alkaloids were named as consoramides A–C (1-3).

Macrosynteny analysis between Lentinula edodes and Lentinula novae-zelandiae reveals signals of domestication in Lentinula edodes

The basidiomycete fungus Lentinula novae-zelandiae is endemic to New Zealand and is a sister taxon to Lentinula edodes, the second most cultivated mushroom in the world. To explore the biology of this organism, a high-quality chromosome level reference genome of L. novae-zelandiae was produced. Macrosyntenic comparisons between the genome assembly of L. novae-zelandiae, L. edodes and a set of three genome assemblies of diverse species from the Agaricomycota reveal a high degree of macrosyntenic restructuring within L. edodes consistent with signal of domestication. These results show L. edodes has undergone significant genomic change during the course of its evolutionary history, likely a result of its cultivation and domestication over the last 1000 years.

A small Ustilago maydis effector acts as a novel adhesin for hyphal aggregation in plant tumors

The biotrophic basidiomycete fungus Ustilago maydis causes smut disease in maize. Hallmarks of the disease are characteristic large tumors in which dark pigmented spores are formed. Here, we functionally characterized a novel core effector lep1 (late effector protein 1) which is highly expressed during tumor formation and contributes to virulence. We characterize lep1 mutants, localize the protein, determine phenotypic consequences upon deletion as well as constitutive expression and analyze relationships with the repellent protein Rep1 and hydrophobins. In tumors, lep1 mutants show attenuated hyphal aggregation, fail to undergo massive late proliferation and produce only few spores. Upon constitutive expression, cell aggregation is induced and the surface of filamentous colonies display enhanced hydrophobicity. Lep1 is bound to the cell wall of biotrophic hyphae and associates with Rep1 when constitutively expressed in hyphae. We conclude that Lep1 acts as a novel kind of cell adhesin which functions together with other surface-active proteins to allow proliferation of diploid hyphae as well as for induction of the morphological changes associated with spore formation.

An endophytic Schizophyllum commune Fr. exhibits in-vitro and in-vivo antidiabetic activity in streptozotocin induced diabetic rats

The present study aimed at isolation of endophytic basidiomycetous fungi and evaluation of their in-vitro and in-vivo antidiabetic potential. Preliminary screening for in-vitro activity was carried out using α-glucosidase inhibition assay. An endophytic isolate Sch1 (isolated from Aloe vera), identified to be Schizophyllum commune Fr. on molecular basis, exhibiting more than 90% α-glucosidase inhibitiory activity was selected for further studies. Detailed in-vivo investigations for antidiabetic potential of ethyl acetate extract of S. commune (Sch1), at two different doses, were carried out in streptozotocin induced diabetic Wistar rats. Treatment of diabetic rats with S. commune extract caused significant decrease in blood glucose level and increase in body weight after 14 days experimental period. It significantly restored renal parameters including creatinine, blood urea nitrogen, fractional excretion of sodium, and potassium level in diabetic rats. Improvement in lipid profile and level of antioxidant parameters viz. reduced glutathione, thiobarbituric acid reactive species, and superoxide anion generation was also observed after treatment. Liver enzymes (serum glutamic pyruvic transaminase, serum glutamic-oxaloacetic transaminases, and alkaline phosphatase) homeostasis was found to be markedly improved in diabetic rats administered with S. commune extract. The effects were more pronounced at higher concentration and comparable to acarbose which was used as positive control. Phytochemical analysis revealed the presence of phenolics and terpenoids in the ethyl acetate extract. This is the first report highlighting the therapeutic potential of an endophytic S. commune in the management of diabetes.

The abundance and diversity of Basidiomycetes fungi in sago bark waste

This study was aimed to determine the abundance and diversity of Basidiomycetes fungi on sago bark waste. This research was conducted in January-February 2020 at Tondok Alla village, Telluwanua district, Palopo city (as location I) and Kalotok village, South Sabbang district, North Luwu regency (as location II). Climate data for the study period were obtained from the BMKG online website. The morphology of the fungi obtained from the sago bark waste was observed and identified morphologically for stalk color, cap structure and cap colour. The number of identified Basidiomycetes were analyzed to obtain relative abundance, species richness, evenness, Shannon Wiener diversity index, Simpson dominance index, and community similarity index. The climate observation results showed that, the average temperature was 27.74 (° C), 80.36% humidity, 12.37 mm of rainfall, and 4 hours / day of sun exposure. The fungi observation results showed that, several species of Basidiomycetes fungi was observed at both locations. Schizophyllum commune is the dominant species at both sites, and Ganoderma sp. the least. The species richness index, species evenness index, and diversity index at location I were higher than location II, while the Simpson dominance index was the highest in location II. Both locations have the same community structure based on the similarity index.

Modified culture assay to obtain a diversity of hyphal structures of Ceratobasidium theobromae-VSD pathogen on cocoa

Abstract. Junaid M, Guest D. 2021. Modified culture assay to obtain a diversity of hyphal structures of Ceratobasidium theobromae, VSD pathogen on cocoa. Biodiversitas 22: 1879-1886. Ceratobasidium theobromae, a causal agent of vascular streak dieback (VSD) disease, is a fastidious Basidiomycete fungus devastating cocoa in Southeast Asia Melanesia. One sought-after in vitro technique is pathogen subculture. As an obligate parasite, growing the pathogen onto an artificial medium is always problematic. In this paper, a new design is demonstrated to obtain a single colony of the pathogen with hyphal diversity. Putative C. theobromae is obtained from infected leaves and petioles of cocoa using rigorous surface sterilization before culturing on standard water agar (WA) medium. Once the fungus grows out from the tissue, the infected plant tissue is then removed carefully, leaving mycelium's uninterrupted growth. About 200 mL of liquid Corticium culture medium (CCM) is injected to submerge the solid medium layer, nurture hyphae development, and allow generative structure formation. Molecular amplification with a pair primer of ITS 1B (forward) and 4B (reverse) specific for fungal Basidiomycete DNA with a touchdown undertook thermal cycler program. PCR product amplification successfully confirmed the presence of C. theobromae DNA collected from the samples with VSD symptomatic lesions and identified a diversity of hyphal and branching formations.

Biosorción y tolerancia de Pb, Cr y Cd por la biomasa de Pleurotus ostreatus (Jacq. Ex Fr.) P. Kumm

A nivel mundial, el uso indiscriminado de productos metálicos vertidos en agua utilizada en la agricultura ha generado una grave contaminación, por lo tanto, es importante establecer una metodología para su descontaminación a través de procesos biológicos, con hongos basidiomicetos ya que se ha demostrado que pueden degradar una serie de contaminantes orgánicos persistentes utilizando enzimas extracelulares, además de eliminar metales disueltos del agua mediante biosorción, actuando, como un intercambiador natural. Los objetivos de este trabajo fueron determinar entre tres metales (Pb, Cr y Cd) cuál fue removido más eficientemente de la solución acuosa por el micelio del hongo Pleurotus ostreatus, así como evaluar su tolerancia y describir los efectos causados por cada uno sobre su estructura celular. La adsorción de metales por el micelio en medio líquido se evaluó utilizando medio Kirk modificado, se cuantificaron las concentraciones retenidas durante 8 días en solución de 20 mg L-1 de cada elemento, los resultados indicaron que la adsorción de Pb (75%) fue la más eficiente, seguida de Cr (42%) y Cd (2.25%). En los resultados en medio de cultivo sólido (PDA) ninguna concentración de Pb y Cr inhibió el crecimiento del micelio, sin embargo, con Cd se inhibió a partir de 60 mg L-1; no obstante, los tres elementos causaron en el micelio alteraciones a nivel estructural. En conclusión, la cepa de P. ostreatus presento tolerancia y biosorción significativa (p≤ 0.05) para

A comparative study on the laccase activity of four basidiomycete fungi with different lignocellulosic residues via solid-state fermentation

The laccase producing abilities of four Basidiomycete fungi species were compared using solid-state fermentation using four different lignocellulosic residues. The biosynthetic potential of the Basidiomycetes was highly dependent on the type of fungi. In general, the laccase secreting ability of Cerrena unicolor Han 849 was greater than Lenzites betulinus Han 851, Stropharia rugosoannulata Han 1321, and Auricularia heimuer Han 1333. The maximum laccase production of C. unicolor Han 849 was approximately 11.25, 122.26, and 15.27 times higher than L. betulinus Han 851, S. rugosoannulata Han 1321 and A. heimuer Han 1333, respectively. Different species of fungi had a preference in lignocellulosic residues. The presence of Firmiana platanifolia was conducive to secreting laccase via C. unicolor Han 849 during solid-state fermentation. A continuous and stable laccase production via C. unicolor Han 849 was an obvious advantage of solid-state fermentation with any of the four lignocellulosic residues used. The maximum laccase production of C. unicolor Han 849 using Firmiana platanifolia was approximately 2.12, 1.68, and 6.13 times higher than Populus beijingensis, Sorghum bicolor, and Oryza sativa, respectively. These findings will be helpful for developing new productivity strains in industrial applications and selecting suitable lignocellulosic residues for laccase production.

Screening of endophytic fungi from oil palm (Elaeis guineensis) in producing exopolysaccharides

Abstract. Yurnaliza Y, Jamilah I, Hartanto A, Lutfia A. 2021. Screening of endophytic fungi from oil palm (Elaeis guineensis) in producing exopolysaccharides. Biodiversitas 22: 1467-1473. Exopolysaccharides (EPS) are microbial polysaccharides with a high biotechnological application in many fields due to their bioactivity and biocompatibility. Endophytic fungi are potential agents for producing EPS even though they remained under-exploited, especially those originating as indigenous strains from oil palm (Elaeis guineensis Jacq.). The present study reports on EPS production by a collection of endophytic fungi isolated from the petioles of oil palm under submerged fermentation. The culture medium was formulated with sucrose as C-source to trigger the secretion of EPS by the strains. Isolation of EPS was done through absolute ethanol precipitation in cold conditions. A total of 29 endophytic fungal strains was recovered from the foliar part of the plants. Molecular identification based on ITS-rDNA region and phylogenetic construction of each lineage revealed the dominant species from Pestalotiopsidaceae (syn. Amphisphaeriaceae), followed by Hypoxylaceae, Pleosporaceae, Didymosphaeriaceae, Sporocadaceae, and other minor families. In general, most isolates were ascomycetous fungi along with a basidiomycetous and zygomycetous fungus. After fermentation for 10 days, three fungal endophytes identified as Annulohypoxylon thailandicum P8 (Hypoxylaceae), Pseudopestalotiopsis simitheae P1 (Pestalotiopsidaceae), and Diaporthe eucalyptorum P11 (Diaporthaceae) secreted EPS higher in values than the others. The most prominent strain was A. thailandicum P8 with a yield of >50 mg/100 mL of filtrate solution. Based on FT-IR spectral analysis, the EPS product was detected to contain carboxyl, carbonyl, glycosidic bonds, and hydroxyl groups hereafter confirmed the characteristics of exopolysaccharides. The results demonstrated that the EPS may be evaluated for its bioactivity in a future study.

The characteristics of soil fungal community in degraded alpine meadow in the Three Rivers Source Region, China.

To clarify the variation of species composition, diversity, and functional structure of soil fungi community along alpine meadow degradation,we examined the characteristics and controlling factors of soil fungal communities in non-degraded, lightly degraded, moderately degraded, severely degraded and extremely degraded (black soil beach) alpine meadows at the Three Rivers Source Region, based on the high-throughput gene sequencing and FUNGuild functional prediction. The results showed that the dominant phyla in alpine meadow soil were Ascomycota, Basidiomycetes, and Mortierellomycota. Species composition of soil fungal community varied greatly in alpine meadow under different levels of degradation. The abundance of Cladosporium flabelliforme, Entoloma sodale, Hygrocybe conica, Inocybe sp. and Trichocladium opacum increased, while that of Gibberella tricincta and Dactylonectria macrodidyma decreased following grassland degradation. The meadow under severe degradation had higher soil fungal Chao1 index, while that under light degradation had lower Shannon index and Simpson index. The abundance of pathologic, symbiotic, and saprophytic types of fungi varied among different alpine meadows. Along with the grassland degradation, the abundance of soil symbiotic fungi decreased, while that of pathological fungi increased. The soil fungal community and functional compositions changed obviously with degradation in the alpine meadow. Plant aboveground biomass, soil water content, pH, total organic carbon, total nitrogen, ammonium nitrogen, available phosphate, total potassium and AN/AP (ratio of available nitrogen and available phosphorus) were the main driving factors for the variations in soil fungal community structure.