Greater Fungal Diversity Research Articles

Fungal Diversity in the Wounded Tissues of Gyrinops walla Trees and the Surrounding

Gyrinops walla (Gaertn) of family Thymelaeaceae, is believed to be endemic to Sri Lanka and is mainly found in the lowland wet zone where the elevation is lower than 1,000 m and the annual rainfall is between 2,000 to 3,000 mm. This species is known for producing a valuable resin called agarwood in its trunk after being infected by pathogens, mainly fungi. Over 20 capable fungal species have been identified to stimulate agarwood formation in the trees of the agarwood- producing genus, Aquilaria. However, since such information is lacking for G. walla, this study aimed to determine the fungal taxa that induce agarwood formation in G. walla and to compare the fungal diversity between G. walla tissues, surrounding trees, and the soil. Samples were taken from four locations in the wet zone, Olugala, Morapitiya, Weragala, and Elpitiya, and one location in the intermediate zone, Kirimetimulla. Collected naturally wounded tissues from G. walla trees of those locations were surface sterilized before culturing. In addition, the stem samples were taken from the surrounding trees at 5 m radius from the sampled G. walla trees. Soil samples were collected at each location at 2.5 m distance along the north south directions of sampled G. walla trees which is from the sub-surface. A standard dilution series up to 1:10,000 was prepared for soil culturing. All the fungal colonies emerging from initial soil, stem cultures were isolated as pure cultures in separate PDA plates. Based on the colony morphology and growth parameters, all the pure cultures were categorized into 13 fungal isolates. Morphological and microscopic characteristics were used to identify the fungal isolates. Out of the 13, six isolates were identified as Aspergillus sp. (1, 2, 3), Rhizopus sp., Trichoderma sp., and Mucor sp. The unidentified isolates, due to the lack of reproductive structures, were named as morphotypes 5, 7, 8, 9, 11, 12 and 13. After identification, their presence and frequency of occurrence in different sample types i.e. resinous tissues and nonresinous tissues of G. walla, surrounding tree tissues and soil were evaluated in all five locations. For the comparison, diagrams were built. Thereby, predominant fungal isolates in each of the sample types were identified. Based on the occurrence of fungal isolates in each location, Olugala had the greatest fungal diversity, while Morapitiya had the lowest. Morphotype 07 was identified as the dominant isolate in resinous tissues of G. walla due to the presence of 15 isolates. Rhizopus sp. was also found as a common fungal isolate in the wounded tissues of all five locations. Trichoderma sp. was more abundant in the surrounding, while Aspergillus sp (1) was dominant in soil. Fungal isolates in resinous tissues were also present either in the non-resinous tissues of G. walla, surrounding tree tissues, or soil. Therefore, inocula are believed to enter the wounded tissues from nearby trees or from the soil, and spores from water, wind or carriers like insects. 
 Keywords: Gyrinops walla, Fungal isolates, Surrounding trees, Soil

Aquatic fungi diversity of upper lake and Hathaikheda reservoir of Bhopal Madhya Pradesh

The fungal flora of two water bodies Upper Lake and Hathaikheda Reservoir of Bhopal Madhya Pradesh were isolated during the course of study from January 2017 to December 2018. During the present study, total 600 isolates, comprising of 17 genera and 24 species of aquatic and terrestrial fungi were recorded from two water bodies. These fungi belonged to various orders of the group Oomycota, Ascomycota and Zygomycota. Members of Saprolegniales were dominant over the rest of the orders of fungi at both the water bodies. Upper Lake showed a great fungal diversity compared to that of Hataikheda Reservoir as total 332 isolated of fungi were isolated from Upper Lake, while as only 268 isolated of fungi were isolated from Hathaikheda Reservoir. Majority of the fungal species were common at both the water bodies, but Aphanomyces laevis, Aphanomyces invades, Saprolegnia hypogyanna, Pythium undulatum and Aspergillus terrus were only specific to Upper Lake.

Illumina-Based Analysis Yields New Insights Into the Fungal Contamination Associated With the Processed Products of Crataegi Fructus.

Crataegi Fructus, a medicinal and edible herb in China, has been considered a popular dietary supplement globally. It is used for the treatment of dyspepsia and chronic heart failure according to the Chinese Pharmacopoeia (2020). However, fungal contamination in Crataegi Fructus affects its quality and safety, thus preventing its global promotion. In this study, we comprehensively studied the fungal community in processed products of Crataegi Fructus by high-throughput sequencing. A total of 21 Crataegi Fructus samples were collected from five provinces in China, and the samples were divided into five groups based on collection areas, as well as into three groups based on processing methods. We then targeted the internal transcribed spacer 2 sequence through the Illumina Miseq PE300 platform to investigate fungal composition and diversity. Results showed that all 21 samples were detected with fungal contamination, and Ascomycota was dominant at the phylum level. In the groups based on collection areas, Dothideomycetes, Pleosporaceae, and Alternaria were dominant at the class, family, and genus levels, respectively. In the groups based on processing methods, Dothideomycetes, Aspergillaceae, and Alternaria were the most abundant at the class, family, and genus levels, respectively. Differences in fungal communities between various groups were also observed. Furthermore, a total of 115 species were identified, among which seven were potential toxigenic, namely, Trichothecium roseum, Alternaria tenuissima, Aspergillus carbonarius, Penicillium brevicompactum, Aspergillus fumigatus, Rhizopus microspores, and Pichia fermentans. In conclusion, this study reveals great fungal richness and diversity of Crataegi Fructus, providing references for the prevention and control of fungal contamination of Crataegi Fructus in practical production.

Fungal diversity and mycotoxins detected in maize stored in silo-bags: a review.

Silo-bags are hermetic storage systems that inhibit fungal growth because of their atmosphere with low humidity, as well as low pH and O2 concentrations, and a high CO2 concentration. If a silo-bag with stored maize loses its hermetic nature, it favors the development of fungi and the production of mycotoxins. To the best of our knowledge, this is the first review on the diversity of fungal species and mycotoxins that were reported in maize stored under the environmental conditions provided by silo-bags. The genera Penicillium, Aspergillus and Fusarium were found more frequently, whereas Acremonium spp., Alternaria sp., Candida sp., Cladosporium sp., Debaryomyces spp., Epiconum sp., Eupenicillium spp., Eurotium sp., Eurotium amstelodami, Hyphopichia spp., Hyphopichia burtonii, Moniliella sp., Wallemia sp. and genera within the orden Mucorales were reported less recurrently. Despite finding a great fungal diversity, all of the studies focused their investigations on a small group of toxins: fumonisins (FBs), aflatoxins (AFs), deoxynivalenol (DON), zearalenone (ZEA), patulin (PAT), toxin T2 (T2) and ochratoxin (OT). Of the FBs, fumonisin B1 and fumonisin B2 presented higher incidence percentages, followed by fumonisin B3 . Of the AFs, the only one reported was aflatoxin B1. The mycotoxins DON, ZEA and OT were found with lower incidences, whereas PAT and T2 were not detected. Good management practices of the silo-bags are necessary to achieve a hermetically sealed environment, without exchange of gases and water with the external environment during the storage period. © 2022 Society of Chemical Industry.

Deep-sea hydrothermal vent sediments reveal diverse fungi with antibacterial activities.

Relatively little is known about the diversity of fungi in deep-sea, hydrothermal sediments. Less thoroughly explored environments are likely untapped reservoirs of unique biodiversity with the potential to augment our current arsenal of microbial compounds with biomedical and/or industrial applications. In this study, we applied traditional culture-based methods to examine a subset of the morphological and phylogenetic diversity of filamentous fungi and yeasts present in 11 hydrothermally influenced sediment samples collected from eight sites on the seafloor of Guaymas Basin, Mexico. A total of 12 unique isolates affiliating with Ascomycota and Basidiomycota were obtained and taxonomically identified on the basis of morphological features and analyses of marker genes including actin, β-tubulin, small subunit ribosomal DNA (18S rRNA), internal transcribed spacer (ITS) and large subunit ribosomal DNA (26S rRNA) D1/D2 domain sequences (depending on taxon). A total of 11 isolates possess congeners previously detected in, or recovered from, deep-sea environments. A total of seven isolates exhibited antibacterial activity against human bacterial pathogens Staphylococcus aureus ATCC-35556 and/or Escherichia coli ATCC-25922. This first investigation suggests that hydrothermal environments may serve as promising reservoirs of much greater fungal diversity, some of which may produce biomedically useful metabolites.

The Mycobiota of the Deep Sea: What Omics Can Offer.

The deep sea (>1000 m below sea level) represents one of the most extreme environments of the ocean. Despite exhibiting harsh abiotic conditions such as low temperatures, high hydrostatic pressure, high salinity concentrations, a low input of organic matter, and absence of light, the deep sea encompasses a great fungal diversity. For decades, most knowledge on the fungal diversity of the deep sea was obtained through culture-dependent techniques. More recently, with the latest advances of high-throughput next generation sequencing platforms, there has been a rapid increment in the number of studies using culture-independent techniques. This review brings into the spotlight the progress of the techniques used to assess the diversity and ecological role of the deep-sea mycobiota and provides an overview on how the omics technologies have contributed to gaining knowledge about fungi and their activity in poorly explored marine environments. Finally, current challenges and suggested coordinated efforts to overcome them are discussed.

Culturable root endophyte communities are shaped by both warming and plant host identity in the Rocky Mountains, USA

Abstract Understanding the biogeographic patterns of root-associated fungi and their sensitivity to temperature may improve predictions of future changes in terrestrial biodiversity and associated ecosystem processes, but data are currently limited. Anticipating change will require combining observational data, which predict how climatic factors limit current species distributions, with direct manipulations of climate, which can isolate responses to specific climate variables. Root endophytes are common symbionts of plants, particularly in arctic and alpine environments, yet their responses to climate warming are not resolved. Here, we directly cultured endophytic fungi from roots collected along altitudinal gradients in replicated mountain watersheds and from a 27 y field warming experiment in the Rocky Mountains, USA, to improve understanding of climate impacts on fungal root endophytes. Fungal taxa that were common at high elevations declined most under climate warming, whereas low elevation dominants responded neutrally or increased with experimental warming. Altitudinal gradients in fungal communities were strongly specific to the plant host species. Specifically, Poa species had 25–60% greater fungal isolate abundance and 25–38% greater fungal diversity at high elevations than at low elevation sites. In contrast, Festuca thurberi had 64% lower fungal diversity on roots at high elevation than at low elevation. Our results help to improve understanding of the potential for climate change to alter plant-fungal interactions in mountain ecosystems.

The mycobiomes and bacteriomes of sputum, saliva, and home dust.

Respiratory microbiome is an understudied area of research compared to other microbiomes of the human body. The respiratory tract is exposed to an array of environmental pollutants, including microbes. Yet, we know very little about the relationship between environmental and respiratory microbiome. The primary aim of our study was to compare the mycobiomes and bacteriomes between three sample types from the same participants, including home dust, saliva, and sputum. Samples were collected from 40 adolescents in a longitudinal cohort. We analyzed the samples using 16s bacterial rDNA and ITS fungal rDNA gene sequencing, as well as quantitative PCR with universal fungal and bacterial primers. Results showed that home dust had the greatest alpha diversity between the three sample types for both bacteria and fungi. Dust had the highest total fungal load and the lowest total bacterial load. Sputum had greater bacterial diversity than saliva, but saliva had greater fungal diversity than sputum. The distribution of major bacterial phyla differed between all sample types. However, the distribution of major fungal classes differed only between sputum and saliva. Future research should examine the biological significance of the taxa found in each sample type based on microbial ecology and associations with health effects.

Covering the Cover

Covering the Cover

Revegetation technique changes root mycorrhizal colonisation and root fungal communities: the advantage of direct seeding over transplanting tube-stock in riparian ecosystems

Riparian ecosystems are among the most degraded worldwide as they are subject to a range of human-mediated disturbances at different scales. As riparian vegetation plays a key role in maintaining waterway and landscape health, restoration often focuses on promoting riparian vegetation re-establishment. The role of below-ground processes and agents in the process of revegetation is often overlooked even though agents like mycorrhizal fungi enhance seedling establishment and plant growth. In this study we aimed to understand whether colonisation by local mycorrhizal fungi can be advantageous to the early phases of plant establishment during revegetation, whether revegetation technique influences the extent of this potential colonisation, and has the potential to enhance revegetation outcomes. We examined mycorrhizal colonisation rate and species composition of root fungal communities in direct seeded and tube-stock plants and compared them with local native vegetation in a retarding basin in Victoria, Australia, then modelled the relationship between root fungal community attributes and plant size. Results indicate that revegetation technique influenced the colonisation rate, diversity and composition of root fungal communities. Moreover, greater fungal diversity and greater similarity of fungal communities to the mycobiota of native vegetation were positively related with growth of seeded plants but showed negative or little relationship to size of tube-stock plants. High colonisation rates of plant species studied, and relationships between fungal community characteristics and plant growth of seeded plants provide the first evidence of the potential importance of mycorrhizal associations for these plant species in a revegetation context.

EXAMINATION OF FUNGAL DIVERSITY PRESENT ON MEXICAN FREE-TAILED BATS, TADARIDA BRASILIENSIS MEXICANA, IN COLORADO

We surveyed a summer population of Tadarida brasiliensis mexicana in south-central Colorado to gain an initial characterization of the resident mycobiome (i.e., fungal biota) present on their body surfaces. We cultured fungal spores from bats captured in early and late summer and then conducted DNA barcoding analysis for taxonomic identification. Phylum Ascomycota dominated the ectomycotal (i.e., fungi present on body surfaces) community, with the most common genera including Aspergillus, Penicillium, Cladosporium, and Eurotium. Phylum Basidiomycota constituted a smaller proportion of fungal isolates and was composed primarily of Cryptococcus, Peniophora, Cystofilobasidium, and Sistotrema. We found seasonal differences in fungal community composition, with diversity and evenness increasing from June to August. There were notable differences in fungal communities present on adult vs. juvenile bats, with juveniles having a greater number of unique genera, greater fungal diversity, and lower species evenness compared with adults. We isolated a number of fungal species that are capable of growing at low temperatures, indicating that T. b. mexicana harbors viable psychrophilic fungi.

Field Fungal Diversity in Freshly Harvested Maize

Maize is a major crop in China and maize production in Heilongjiang Province ranks No.1 in the country in annual maize production in the whole country. Maize is prone to invasion by fungi and mycotoxins produced by these fungi are proven to be serious threats to animals as well as human health. Through high through-put sequencing we detected the dominant phylum to be Ascomycota; Dothideomycetes, Sordariomycetes, Eurotiomycetes and Tremellomycetes, Saccharomycetes were the dominant classes; Hypocreales, Eurotiales, Capnodiales, Saccharomycetales, Tremellales, and Pleosporales were the main orders; Nectriaceae, Trichocomaceae, Cladosporiaceae, Debaryomycetaceae, Tremellaceae, and Pleosporaceae were major families; Gibberella, Cladosporium, Papiliotrema, Penicillium, Scheffersomyces, Talaromyces, and Epicoccum were the most abundant phylotypes at the genus level. Epicoccum_nigrum, Gibberella_zeae, Papiliotrema_flavescens, and Scheffersomyces_shehatae were the dominant fungal species. Great fungal diversity was observed in the maize samples harvested in the five major maize-growing regions in Heilongjiang Province. Maize-1 in Nenjiang County was observed to have the greatest fungal diversity and abundance among the five regions. Since some of the fungal species are mycotoxin producing, it is necessary to take precautions to ensure the maize is stored under safe conditions to prevent the occurrence of mycotoxins and the growth and reproduction of other fungi which results in deterioration in the quality of maize.

Field Fungal Diversity in Freshly Harvested Japonica Rice

Rice is a major food crop in China and Japonica rice production in Heilongjiang Province ranks No.1 in total annual rice production in the country. Rice is prone to invasion by fungi and mycotoxins produced by the fungi are proven to be serious threats to human health. The objective of the present study was to investigate fungal diversity of freshly harvested rice in the four main cultivation regions of Heilongjiang Province in order to find the difference of dominant fungi among the four regions. Through high throughput sequencing we detected Ascomycota accounts for absolute dominant phylum; Dothideomycetes, Sordariomycetes, Tremellomycetes, Microbotryomycetes, and Eurotiomycetes were dominant classes; Capnodiales, Hypocreales, and Pleosporales were the main orders; Cladosporiaceae, Pleosporaceae, Nectriaceae, Clavicipitaceae, Tremellaceae, Phaeosphaeriaceae, Trimorphomycetaceae, Sporidiobolaceae, Bionectriaceae, and Trichocomaceae were major family; Cladosporium, Epicoccum, Fusarium, and Alternaria were the most abundant phylotypes at genus level; Epicoccum nigrum, Gibberella zeae, and Fusarium proliferatum were the dominant fungal species. Great fungal diversity was observed in the rice samples harvested in the four major Japonica rice-growing regions in Heilongjiang province. However, no significant difference in diversity was observed among the four regions, likely due to the relatively close geographical proximity leading to very similar climatic conditions. Since some of the fungal species produce mycotoxins, it is necessary to take precautions to ensure the rice is stored under safe conditions to prevent the production of mycotoxins. This is the first report on investigation of field fungal diversity in freshly harvested Japonica rice in Heilongjiang Province in China.

Macrofungal diversity in an isolated and fragmented Mediterranean Forest ecosystem

Agricultural transformation has led to scarcity and fragmentation of Mediterranean forests with unknown effects on the fungal diversity they harbour. La Orbada forest is an isolated holm-oak forest in the province of Salamanca, in western Iberian Peninsula. This forest is threatened by various factors, mainly: habitat fragmentation, the possible barrier effects caused by geographical isolation and pressure from humans and livestock. In order to assess the state of conservation of the ecosystem’s macrofungal community and its ecological integrity, the fruitbodies of epigeous macromycetes were studied over a five-year time series (2009–2013). One hundred and eighty-nine species were identified, dominating Basidiomycetes (Tricholomataceae, Cortinariaceae and Russulaceae families). We also analysed: (i) the seasonal and annual behaviour of each species, ii) distribution of taxa according to their mode of nutrition, iii) the similarity of biodiversity between various plots inside the forest and with other ecosystems dominated by Quercus species. The data obtained indicate a greater fungal diversity than in other Mediterranean ecosystems and a good degree of conservation, with no signs of barrier or forest edge effects. One plot has been identified as a macrofungal biodiversity hotspot. The main factors threatening the area have been analysed and conservation measures proposed.

Effects of preparation of clear‐cut forest sites on the soil mycobiota with consequences for Scots pine growth and health

AbstractFungal abundance and diversity were assessed in two differently managed forest soils. In soil 1, chipped woody debris had been spread on the top soil and mixed with the soil by standard deep ploughing to 50 cm. In soil 2, woody debris was removed and there was no ground preparation. Ten years later, the different methods of management resulted in unexpectedly distinctive habitat heterogeneity with a high variation in structure of the mycobiota communities. Incorporation of woody debris into soil resulted in lower abundance of fungi but greater fungal diversity (which may enhance ecosystem stability) and was beneficial for the growth of Scots pines. Removal of post‐harvest woody debris from the surface of the clear‐cut site with no subsequent ground preparation, compared with incorporating chipped debris and deep ploughing, resulted in the soil of the subsequent 10‐year‐old Scots pine plantation having: (a) 159‐fold greater abundance of fungi, (b) lower fungal diversity, (c) different fungal community composition, (d) higher proportion of mycorrhizal fungi, (e) no root rot pathogens, (f) less tree biomass. The study showed that removal of post‐harvest woody debris and no ground preparation is potentially beneficial for the health of young coniferous trees.

Effect of elevated temperatures on composition and diversity of microfungal communities in natural and urban boreal soils, with emphasis on potentially pathogenic species

Elevated temperatures differentially affect the development of cultivated microfungal assemblages, including species potentially pathogenic for humans, in various natural and anthropogenic soils. For that reason it is important to know whether the relative abundance and diversity of fungal pathogenic species increase at elevated soil temperatures. We compared successional changes in microfungal species diversity in natural (Histic Leptosol, Umbric Albeluvisol) and anthropogenic (Urbic Technosol) soils of the boreal zone of European Russia at temperatures of 10, 20, 30, and 35°С, and at a water holding capacity of 60% using the soil dilution plate method. The greatest fungal diversity was detected at the lowest but common temperature (10°C) in the investigated regions. The most significant changes in the diversity of fungal assemblages in the process of succession occurred at 20°C. Elevated soil temperatures (30 and 35°С) induced a drastic decrease in species diversity compared with what was observed at 10°C.During the successions, microfungal assemblages in both types of natural soils had the most pronounced differences in species composition at minimal (10°С) and maximal (35°С) soil temperatures. In the anthropogenic soil, microfungal communities at varying stages of succession were more similar at different temperatures, with the exception of the final stages of succession at the highest temperature of 35°C. Independently of soil type, elevated temperature increased (up to 40–90%) the relative abundance of potentially pathogenic microfungal species dangerous for humans. Potentially pathogenic Aspergillus fumigatus was dominant in the natural soils, while Scedosporium aurantiacum dominated in the urban soil. Elevated soil temperatures in combination with high humidity due to climate warming may drastically accelerate the development of potentially pathogenic microfungal species.

Small mammal mycophagy in hemiboreal forest communities of Lithuania

Abstract The diets of small mammals in different hemiboreal spruce-dominated, oak-dominated and mixed forests in western part of Lithuania were studied by examination of fungal spores in fresh fecal pellets of caught animals. In the diets of mice (Apodemus spp.), bank voles (Myodes glareolus), and common and pygmy shrews (Sorex araneus and S. minutus), 22 different fungal taxa were identified, 15 of which were hypogeous fungi. The sporocarp abundance and the spores in fecal samples of Elaphomyces fungi prevailed in study area during this investigation. Although most of the captured individuals consumed fungi, the consumption varied among small mammal species. The data show that the fungi were more frequent and taxonomically diverse in Myodes glareolus than in Apodemus spp. diets. The study provided evidence that the fungal component in the diets of insectivorous Sorex species is more diverse than previously known. The availability of sporocarps and the fungal component in the diets of small mammals showed seasonal effects. Annual hypogeous and epigeous sporocarp abundances did not vary significantly across forest types. The significant difference in mycophagy was observed across all forest cover types, with the greatest fungal diversity in fecal samples collected in mixed coniferous-deciduous tree stands.

Micobiota do solo de uma área de duna na Restinga da Marambaia, Rio de Janeiro, RJ

This study was carried out in order to evaluate soil mycobiota in different soil positions (shoulder, back slope, foot slope) in a dune, located in Restinga da Marambaia, RJ. The studied area of approximately 500 m2 was divided in three parts with vegetation ranging from the shrubs to trees. It was a 50 x 50 m enclosed plot where five 10 cm-deep mini trenches were opened for soil collection. Three composite samples formed by the gathering of five single samples were collected for analysis and characterization of the soil mycobiota. The highest aluminum content and the lowest nutrient content were observed in the foot slope position. The colony unit formation varied from 4.6 x 103 to 9.0 x 104 cuf.g-1. 49 fungi in a total of 85 isolated, belonging to 13 genders and 32 species – were found. Penicillium, Aspergillus and Trichoderma were the most frequent genders. The highest richness value was observed in the back slope position. Trichoderma pseudokoningi was the most common species found in the areas. This study implies that Restinga da Marambaia presents a great fungal diversity.

Genetic relationships among strains of the Aspergillus niger aggregate

We analyzed the genetic relationships between 51 fungal isolates previously identified as A. niger aggregate, obtained from dried fruit samples from worldwide origin and 7 A. tubingensis obtained from Brazilian coffee beans samples. Greater fungal diversity was found in black sultanas. Aspergillus niger sensu stricto was the most prevalent species. It was found in all fruit substrates of all geographical origins. Based on Random Amplification of Polymorphic DNA (RAPD) and β-tubulin sequences data two groups of A. niger were found. In spite of the small number of isolates from Group IV an association between extrolite patterns and molecular clustering is speculated. A. tubingensis were the second most frequent species and this species were clearly subdivided into two groups. The finding of two groups for A. tubingensis strains could not yet explain the contradictions found in the literature about the capability this species for ochratoxin production, because both of them were formed by only non-ochratoxin-producing strains.

Survey and phylogenetic analysis of culturable microbes in the oral secretions of three bark beetle species

AbstractIn a recent study, we reported a previously undescribed behavior in which a bark beetle exuded oral secretions containing bacteria that have antifungal properties, and hence defend their galleries against pervasive antagonistic Hyphomycete fungi. Actinobacteria, a group known for their antibiotic properties, were the most effective against fungi that invade the spruce beetle galleries. In the present study, we describe the isolation and identification of microorganisms from oral secretions of three bark beetles (Coleoptera: Curculionidae: Scolytinae): the spruce beetle, Dendroctonus rufipennis Kirby, the mountain pine beetle, Dendroctonus ponderosae Hopkins, and the pine engraver, Ips pini Say. Bacteria isolated from these three species span the major bacterial classes α‐, β‐, and γ‐Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, except for D. ponderosae, which yielded no α‐proteobacteria or Bacteroidetes isolates. Spruce beetles and pine engraver beetles had similar numbers of α‐proteobacteria isolates, but pine engravers yielded twice as many Bacteroidetes isolates as spruce beetles. In contrast, mountain pine beetles yielded more isolates in the β‐ and γ‐proteobacteria than spruce beetles and pine engravers. The highest percentage of Actinobacteria was obtained from spruce beetles, followed by pine engravers and mountain pine beetles. All of the fungal isolates obtained from the three beetle species were Ascomycetes. The greatest fungal diversity was obtained in spruce beetles, which had nine species, followed by pine engravers with five, and mountain pine beetles with one.