Species Of Wood-decaying Fungi Research Articles

Axenic Culture and DNA Barcode Identification of Wood Decay Fungi from the Maltese Islands

Wood-decaying fungi are important study subjects for their ecological role as well as for their biotechnological applications. They break down lignin, cellulose, and hemicelluloses using enzymes that modify the chemical structure of these complex macromolecules. Due to their ability to degrade wood, these fungi can create structural damage to wooden structures and to trees, especially those with very low level of fitness. Previous studies on wood decay fungi in the Maltese Islands are limited to records and checklists described by a handful of authors. The aim of this study was to provide a comprehensive description of wood decay fungal diversity in the Maltese Islands including an updated checklist based on DNA barcoding, as well as to establish the first wood-decay fungal culture collection at the Biology Department Seed Bank of the University of Malta. Several surveys were carried out during the rainy season along wooded areas of the Maltese Islands as well as in historical gardens. Isolates were identified using macro- and micro-morphological features, dichotomous keys, as well as molecular data. Basidiomes were recorded growing on 14 different host plant species, 11 axenic cultures have been made and 9 species of wood decay fungi have been conclusively identified by DNA barcoding. The collection of the axenic isolates includes one of Aurificaria cf. euphoria, three of Ganoderma resinaceum sl., two of Laetiporus sulphureus, one of Inonotus sp., one of Inonotus rickii anamorph, one of Inocutis tamaricis, one of Stereum hirsutum, and one of Pleurotus eryngii. However, the mycelium of Coriolopsis gallica, though collected and identified, could not be isolated.

Intraspecific interactions among wood-decay fungi alter decay rates and dynamics of interspecific interactions

Interactions among wood-decay fungi can have a profound effect on fungal community composition, decay rates and ultimately the chemical composition of the material remaining after the decay process. Interspecific interactions among fungi as they decay wood have been well-studied but almost nothing is known about the effect of intraspecific interactions between individual genets on the decay process. In this study we examine the effect of both intra- and interspecific competition on wood mass-loss for five species of wood-decay fungi: Cerrena unicolor, Fuscoporia gilva, Irpex lacteus, Stereum ostrea and Trametes versicolor. Four of the five species studied showed a significant increase in mass loss when five individual isolates (genets) of the same species simultaneously colonized aspen test wafers in vitro. The dynamics of interspecific interactions were also significantly impacted by the presence of multiple genets of each species. Taken together, these results demonstrate that intraspecific interactions can change the outcome of interspecific interactions and thus the functioning of the overall community.

Nematodes Consume Four Species of a Common, Wood-Decay Fungus

Since nitrogen is in short supply in wood yet relatively plentiful in the bodies of nematodes, wood-decay fungi have been thought to be nematophagous. In an earlier study, we confirmed the nematophagy of two species of wood-decay fungi (Pleurotus ostreatus and P. pulmonarius), although we also found nematode species that could turn the tables and consume Pleurotus. In this study, we tested interactions between nematode species and Fomitopsis, another genus of common wood-decay fungi. Four geographically distinct isolates, or provenances, within each of four species (i.e., the European F. pinicola and three North American species: F. ochracea, F. schrenkii, and F. mounceae) were confronted with a total of twenty nematode species (twenty-four strains) in four experiments. Nematophagy was observed much less frequently in Fomitopsis than in Pleurotus: only 31 of the 516 interactions (6%), overall, resulted in nematophagy by a Fomitopsis isolate, whereas with Pleurotus, the result was 16 of 28 (57%). In contrast, all 20 species of nematode here were capable of mycophagy and dominated interactions with all isolates of Fomitopsis overall. Clearly, not all wood-decay fungi are as strongly nematophagous as the Pleurotus species. Perhaps arboreal nematodes even tend towards mycophagy, given the limiting nitrogen in wood.

Retraction Note: Evolution of substrate-specific gene expression and RNA editing in brown rot wood-decaying fungi.

Fungi that decay wood have characteristic associations with certain tree species, but the mechanistic bases for these associations are poorly understood. We studied substrate-specific gene expression and RNA editing in six species of wood-decaying fungi from the 'Antrodia clade' (Polyporales, Agaricomycetes) on three different wood substrates (pine, spruce, and aspen) in submerged cultures. We identified dozens to hundreds of substrate-biased genes (i.e., genes that are significantly upregulated in one substrate relative to the other two substrates) in each species, and these biased genes are correlated with their host ranges. Evolution of substrate-biased genes is associated with gene family expansion, gain and loss of genes, and variation in cis- and trans- regulatory elements, rather than changes in protein coding sequences. We also demonstrated widespread RNA editing events in the Antrodia clade, which differ from those observed in the Ascomycota in their distribution, substitution types, and the genomic environment. Moreover, we found that substrates could affect editing positions and frequency, including editing events occurring in mRNA transcribed from wood-decay-related genes. This work shows the extent to which gene expression and RNA editing differ among species and substrates, and provides clues into mechanisms by which wood-decaying fungi may adapt to different hosts.

Carbon and nitrogen acquisition strategies by wood decay fungi influence their isotopic signatures in Picea abies forests

We examined whether sporocarp carbon and nitrogen isotope ratios (δ 13 C and δ 15 N values) reflected different functional strategies in 15 species of wood decay fungi. In Finnish Picea abies forests, we compared sporocarp δ 13 C and δ 15 N against log diameter, proximity to ground, and three wood decay types, specifically brown rot, nonselective white rot, and selective white rot (targeting hemicellulose and lignin preferentially). In regression analysis (adjusted r 2 = 0.576), species accounted for 31% of variability in δ 13 C, with factors influencing wood δ 13 C accounting for the remainder. Brown rot fungi and three white rot fungi that selectively attacked hemicellulose ( Heterobasidion parviporum , Phellopilus nigrolimitatus , and Trichaptum abietinum ) were higher in δ 13 C than nonselective white rot fungi. This was attributed to greater assimilation of 13 C-enriched pentoses from hemicellulose by these fungi. The pathogenic white rot fungus Heterobasidion parviporum had higher δ 15 N with proximity to ground and increasing log diameter. This suggested that 15 N-enriched soil N contributed to decomposing logs and that Heterobasidion growing from a bigger resource base had increased access to soil N. These isotopic patterns accordingly reflected both functional diversity of wood decay fungi and site-specific factors. • We investigated strategies of C and N use in wood decay fungi using stable isotopes. • Selective white rot fungi were higher in δ 13 C than nonselective white rot fungi. • Taxa of uncertain white rot type resembled nonselective white rot fungi in δ 13 C. • Spatial arrangements of hemicellulose and cellulose fibers influenced fungal δ 13 C. • If close to ground on big logs, Heterobasidion parviporum accessed soil N.

Substrate specialization and distribution of fungi of the genus <i>Trametes</i> in the southeast of Western Siberia

The authors have studied the features of the substrate specificity of fungi of the genus Trametes s.l. in the southeast of Western Siberia, where this taxon has 10 species. Most species of fungi have a wide substrate spectrum, represented by the wood of various types of woody plants. Fungal species with a wide distribution and a high frequency of occurrence develop a wide range of substrates. Fungal species that are rare and common only in some localities are not numerous; they are characterized by a narrow substrate spectrum. Most species of fungi develop on hardwood, but only a few species can grow on coniferous wood in mountainous areas. Fungal substrates are represented by wood of sixteen species of angiosperms and one species of gymnosperms of woody plants. These ten species of fungi of the Trametes genus have been identified in natural plant communities in the southeast of Western Siberia, while only eight species have been found in anthropogenic habitats. The largest number of fungal species develops on large-sized tree species found in plant communities that are common in the studied region. The number of species of wood-decay fungi on shrubs is insignificant. A small range of species of wood-decay fungi is typical of introduced species (Linden, Oak, Manchurian Walnut, Apple, Ash, Mulberry) growing in urban plantings and in Botanical gardens. Species of fungi with a wide ecological amplitude can develop on the wood of introduced plants.

Effect of burgundy solid extracted from Eastern Red Cedar heartwood on subterranean termites and Wood-decay fungi

Eastern red cedar (ERC) is an abundant natural resource in the U.S. and has been investigated for the extraction of cedarwood oil (CWO) and CWO bioactivity, particularly its use to protect wood against termites and decay fungi. Methanol extraction of ERC sawdust gives a burgundy-colored oil (BO) that is comprised of both CWO and a burgundy solid (BS). The BO was significantly more inhibitory against two species of white-rot decay fungi than CWO alone, suggesting the BS itself might have inhibitory bioactivity. This study investigated the wood preservation properties of the BS alone, in combination with CWO and in conjunction with an amylose inclusion complex (AIC) against termites, brown-rot decay fungi and white-rot decay fungi. Wood was treated by vacuum/pressure impregnation and tested for resistance to subterranean termites and four species of decay fungi. The AIC alone made wood less palatable (16% mass loss versus 32% for H2O) and more toxic (32% mortality versus 26% for H2O) to termites but did not inhibit either brown-rot fungi nor the white-rot Trametes versicolor but did inhibit the white-rot Irpex lacteus (49% mass loss versus 65% for H2O). The CWO led to both lower wood mass loss by termites and higher termite mortality as well as having an inhibitory effect on the white-rot decay fungi. However, a combination of AIC and CWO was necessary to have an inhibitory effect on the brown-rot fungi. The addition of BS to the AIC had a minor inhibitory effect on wood mass loss by termites (11% versus 16% for AIC) but did not inhibit either brown-rot fungi nor the white-rot I. lacteus. The addition of BS to the AIC decreased wood mass loss by the white-rot T. versicolor (38% versus 49% for AIC). Wood blocks impregnated with the combination of the AIC, CWO and BS resulted in the highest termite mortality (i.e., 100%), lowest percentage wood mass loss for the termites (i.e., 6%) and lowest percentage wood mass losses for all four species of wood decay fungi studied (less than 20% overall).

Evolution of substrate-specific gene expression and RNA editing in brown rot wood-decaying fungi.

Fungi that decay wood have characteristic associations with certain tree species, but the mechanistic bases for these associations are poorly understood. We studied substrate-specific gene expression and RNA editing in six species of wood-decaying fungi from the 'Antrodia clade' (Polyporales, Agaricomycetes) on three different wood substrates (pine, spruce, and aspen) in submerged cultures. We identified dozens to hundreds of substrate-biased genes (i.e., genes that are significantly upregulated in one substrate relative to the other two substrates) in each species, and these biased genes are correlated with their host ranges. Evolution of substrate-biased genes is associated with gene family expansion, gain and loss of genes, and variation in cis- and trans- regulatory elements, rather than changes in protein coding sequences. We also demonstrated widespread RNA editing events in the Antrodia clade, which differ from those observed in the Ascomycota in their distribution, substitution types, and the genomic environment. Moreover, we found that substrates could affect editing positions and frequency, including editing events occurring in mRNA transcribed from wood-decay-related genes. This work shows the extent to which gene expression and RNA editing differ among species and substrates, and provides clues into mechanisms by which wood-decaying fungi may adapt to different hosts.

Genomics and Development of Lentinus tigrinus: A White-Rot Wood-Decaying Mushroom with Dimorphic Fruiting Bodies.

Lentinus tigrinus is a species of wood-decaying fungi (Polyporales) that has an agaricoid form (a gilled mushroom) and a secotioid form (puffball-like, with enclosed spore-bearing structures). Previous studies suggested that the secotioid form is conferred by a recessive allele of a single locus. We sequenced the genomes of one agaricoid (Aga) strain and one secotioid (Sec) strain (39.53–39.88 Mb, with 15,581–15,380 genes, respectively). We mated the Sec and Aga monokaryons, genotyped the progeny, and performed bulked segregant analysis (BSA). We also fruited three Sec/Sec and three Aga/Aga dikaryons, and sampled transcriptomes at four developmental stages. Using BSA, we identified 105 top candidate genes with nonsynonymous SNPs that cosegregate with fruiting body phenotype. Transcriptome analyses of Sec/Sec versus Aga/Aga dikaryons identified 907 differentially expressed genes (DEGs) along four developmental stages. On the basis of BSA and DEGs, the top 25 candidate genes related to fruiting body development span 1.5 Mb (4% of the genome), possibly on a single chromosome, although the precise locus that controls the secotioid phenotype is unresolved. The top candidates include genes encoding a cytochrome P450 and an ATP-dependent RNA helicase, which may play a role in development, based on studies in other fungi.

Visual cues for woodpeckers: light reflectance of decayed wood varies by decay fungus

ABSTRACT The appearance of wood substrates is likely relevant to bird species with life histories that require regular interactions with wood for food and shelter. Woodpeckers detect decayed wood for cavity placement or foraging, and some species may be capable of detecting trees decayed by specific fungi; however, a mechanism allowing for such specificity remains unidentified. We hypothesized that decay fungi associated with woodpecker cavity sites alter the substrate reflectance in a species-specific manner that is visually discriminable by woodpeckers. We grew 10 species of wood decay fungi from pure cultures on sterile wood substrates of 3 tree species. We then measured the relative reflectance spectra of decayed and control wood wafers and compared them using the receptor noise-limited (RNL) color discrimination model. The RNL model has been used in studies of feather coloration, egg shells, flowers, and fruit to model how the colors of objects appear to birds. Our analyses indicated 6 of 10 decayed ...

Hexadecyl ammonium chloride amylose inclusion complex to emulsify cedarwood oil and treat wood against termites and wood-decay fungi

Cedarwood oil (CWO) has a wide range of bioactivities, including insect repellency and toxicity, as well as conferring resistance against termites and wood-decay fungi. In previous work examining pressure treatment of wood, ethanol was used as the diluent/carrier for CWO. However, it is preferable to use a water-based carrier for environmental, safety and cost considerations. In this research, we describe the use of a hexadecyl ammonium chloride amylose inclusion complex/polyvinyl alcohol (AIC/PVOH) as an emulsifier for CWO to pressure treat wood. Wood samples were subsequently tested for resistance to termites and four species of wood-decay fungi. Wood was also compared for water absorption and swelling. In the termite test, the lowest wood mass losses were for the AIC/PVOH/CWO (5.4%) and EtOH/CWO (5.4%) treatments, which also had the highest termite mortalities (i.e., 100% and 97.6%, respectively). In general, for wood-decay fungi, wood mass losses were lowest for the EtOH/CWO and AIC/PVOH/CWO treatments and were highest for the Water, EtOH, and AIC/PVOH treatments. Wood blocks treated with AIC/PVOH repelled water as evidenced by higher contact angle, lower mass gain (both by submersion and water saturation) and lower swelling. The results indicated that the amylose inclusion complex makes an excellent emulsifier and the AIC/PVOH/CWO mixture inhibits both termites and wood-decay fungi. The amylose inclusion complex alone was as inhibitory as CWO against termites and also inhibits both water absorption and swelling in treated wood.

Three species of wood-decaying fungi in Polyporales new to China

Three wood-decaying fungi, Ceriporiopsis lagerheimii, Sebipora aquosa, and Tyromyces xuchilensis, are newly recorded in China. The identifications were based on morphological and molecular evidence. The phylogenetic tree inferred from ITS+nLSU sequences of 49 species of Polyporales nests C. lagerheimii within the phlebioid clade, S. aquosa within the gelatoporia clade, and T. xuchilensis within the residual polyporoid clade. The three species are described and illustrated based on Chinese material.

Resveratrol, piceatannol, and isorhapontigenin from Norway spruce (Picea abies) debarking wastewater as inhibitors on the growth of nine species of wood-decaying fungi

The diethyl ether extract obtained from solvent–solvent extraction of Norway spruce (Picea abies) debarking water, a byproduct from debarking of logs in the pulp and paper industry, was tested for inhibition of growth on agar plates of nine species of wood-decaying fungi: Antrodia sinuosa, Antrodia xantha, Coniophora puteana, Fomitopsis pinicola, Gloeophyllum sepiarium, Heterobasidion parviporum, Phlebiopsis gigantea, Serpula himantioides, and Serpula lacrymans. One fraction of the extract showed excellent antifungal activity for a majority of the species, with complete inhibition of growth for A. sinuosa, A. xantha, and G. sepiarium. The major constituents of the most active fraction were identified as the hydroxystilbenes resveratrol, isorhapontigenin (synonymous with methyl piceatannol), and piceatannol (synonymous with astringenin). The active compounds were isolated or synthesized and used individually for dose–response studies. It was found that isorhapontigenin and piceatannol inhibited all growth of A. sinuosa, A. xantha, and G. sepiarium in 0.35 % weight concentration. The hydroxystilbenes were the three most abundant substances in the debarking water and can be obtained as a mixture or in enriched forms. From some extraction steps of the raw debarking water, it would be possible to obtain the hydroxystilbenes in quantities that might be of commercial interest as efficient natural fungicides.

Effect of debarking water from Norway spruce (Picea abies) on the growth of five species of wood-decaying fungi.

Norway spruce (Picea abies) debarking water is an aqueous extract obtained as waste from the debarking of logs at paper mills. The debarking water contains a mixture of natural compounds that can exhibit diverse biological activities, potentially including fungicidal activity on some species of wood-decaying fungi. Thus, we investigated the growth rates of such fungi on agar plates to which debarking water extracts had been added. The experiment included five wood-decaying fungi, viz. Gloeophyllum sepiarium, Oligoporus lateritius, Ischnoderma benzoinum, Junghuhnia luteoalba, and Phlebia sp. Growth reduction was observed for all species at the highest tested concentrations of freeze-dried and ethanol-extracted debarking water, the ethyl acetate-soluble fraction and the diethyl ether-soluble fraction. However, the magnitude of the effect varied between different species and strains of individual species. The brown-rot fungi G. sepiarium and O. lateritius were generally the most sensitive species, with the growth of all tested strains being completely inhibited by the ethyl acetate-soluble fraction. These results indicate that development of antifungal wood-protecting agents from debarking water could potentially be a way to make use of a low-value industrial waste.

Nutrients and Trace Elements Content of Wood Decay Fungi Isolated from Oak (Quercus ilex)

The presence of chemical elements and the differences in their concentration in the fruiting bodies of wood decay fungi may reflect their activity either as saprobes or parasites and the intimate physiological relation with the substrate from which they extract their nutrients. In order to test this hypothesis, we carried out a systematic sampling of eight species of wood decay fungi on oak (Quercus ilex). The data show that the concentration of some elements exhibits a very wide range of values for the species tested, which could mean that the relative content of some elements may provide clues about the nature of the substrate and, moreover, about the nutritional physiology. The comparison between the foliar analysis (FA) and the elemental content of fungi may shed light on the specific physiological behaviour of the species. Potassium is an element accumulated in fungal biomass in higher quantities than in the FA. By contrast, calcium appears in foliar analysis in much higher quantities than in fungal fruiting bodies' biomass. Concerning this element, we have also found profound differences between the two species phylogenetic groups and lifestyle. Of all elements measured, we believe that the relative accumulation of K and Ca may be related to the close connection between fungi and the substrate on which they live and may also explain their physiological role as saprobes or parasites. When the lifestyle and the systematic position of the different species sampled were compared, differences also emerged in the content of Na and Ca.

IN VITRO SCREENING OF AN ANTAGONISTIC TRICHODERMA STRAIN AGAINST WOOD DECAY FUNGI

The objective of the in vitro studies was to identify a Trichoderma strain with a high antagonistic potential against the basidiomycetes Ganoderma adspersum, Ganoderma lipsiense, Inonotus hispidus, Polyporus squamosus and the ascomycete Kretzschmaria deusta. For this purpose dual culture and interaction tests in wood blocks as well as investigations on fungal growth and germination behavior of conidia under different conditions were performed. Hyphal interactions were observed by scanning electron microscopy (SEM). The effect of Trichoderma spp. on wood colonization and degradation of wood decay fungi were quantitatively analyzed by means of dry weight loss measurements of wood and qualitatively by histological studies. The different Trichoderma species all showed an antagonistic potential against wood decay fungi in the in vitro studies. However, significant differences between the species and strains were found (P<0.001). Trichoderma atroviride (T-15603.1) showed the highest competitive activity against most wood decay fungi. An influence of physical and chemical parameters, in particular temperature and water potential on growth and germination behavior of conidia was evident. The species of wood decay fungi showed significant differences in their sensitivity when challenged by Trichoderma. Polyporus squamosus showed an extensive resistance in most laboratory tests indicating that target specificity of the antagonist needs consideration.

Decomposition of Japanese beech wood by diverse fungi isolated from a cool temperate deciduous forest

We assessed 62 fungal strains in 31 species of wood decay fungi in the ability to decompose wood blocks of Japanese beech (Fagus crenata) under a pure culture condition. Fungi were collected in a cool temperate beech forest in Japan and isolated from the inside of beech logs and from sporocarps fruiting on logs and snags of beech that were different in diameter and decay class. Fungi in Holobasidiomycetidae showed marked decomposition of lignin and carbohydrate. These fungi were divided into three groups according to the pattern of lignin and carbohydrate utilization. Phanerochaete filamentosa decomposed lignin selectively. Lampteromyces japonicus, Steccherinum rhois, Trichaptum biforme, Stereum ostrea, Mycena haematopoda, Antrodiella albocinnamomea, Daedalea dickinsii, Daedaleopsis tricolor, Ganoderma tsunodae, and Trametes versicolor decomposed lignin and carbohydrates simultaneously. Psathyrella candolleana, Lenzites betulinus, and Trametes hirsuta decomposed carbohydrates selectively. Species in the Phragmobasidiomycetidae and in the Ascomycota caused low mass loss of wood.

Variation in germination percentage of basidiospores collected successively from wood decay fungi in culture

Successive collections of basidiospores, produced in culture from the same hymenial areas of four species of wood decay fungi, were tested for spore germination percentage on malt extract agar under controlled conditions. Spores from white rot fungi retained high germination levels after 5 weeks of spore production, but germination averages for brown rot fungi decreased by more than 50%. Such variation should be considered in wood pathology research using spore germination bioassay.