Soils of coniferous forest ecosystems are important for the global carbon cycle, and the identification of active microbial decomposers is essential for understanding organic matter transformation in these ecosystems. By the independent analysis of DNA and RNA, whole communities of bacteria and fungi and its active members were compared in topsoil of a Picea abies forest during a period of organic matter decomposition. Fungi quantitatively dominate the microbial community in the litter horizon, while the organic horizon shows comparable amount of fungal and bacterial biomasses. Active microbial populations obtained by RNA analysis exhibit similar diversity as DNA-derived populations, but significantly differ in the composition of microbial taxa. Several highly active taxa, especially fungal ones, show low abundance or even absence in the DNA pool. Bacteria and especially fungi are often distinctly associated with a particular soil horizon. Fungal communities are less even than bacterial ones and show higher relative abundances of dominant species. While dominant bacterial species are distributed across the studied ecosystem, distribution of dominant fungi is often spatially restricted as they are only recovered at some locations. The sequences of cbhI gene encoding for cellobiohydrolase (exocellulase), an essential enzyme for cellulose decomposition, were compared in soil metagenome and metatranscriptome and assigned to their producers. Litter horizon exhibits higher diversity and higher proportion of expressed sequences than organic horizon. Cellulose decomposition is mediated by highly diverse fungal populations largely distinct between soil horizons. The results indicate that low-abundance species make an important contribution to decomposition processes in soils.

Novel species of fungi described in the present study include the following from Australia: Vermiculariopsiella eucalypti, Mulderomyces natalis (incl. Mulderomyces gen. nov.), Fusicladium paraamoenum, Neotrimmatostroma paraexcentricum, and Pseudophloeospora eucalyptorum on leaves of Eucalyptus spp., Anungitea grevilleae (on leaves of Grevillea sp.), Pyrenochaeta acaciae (on leaves of Acacia sp.), and Brunneocarpos banksiae (incl. Brunneocarpos gen. nov.) on cones of Banksia attenuata. Novel foliicolous taxa from South Africa include Neosulcatispora strelitziae (on Strelitzia nicolai), Colletotrichum ledebouriae (on Ledebouria floridunda), Cylindrosympodioides brabejum (incl. Cylindrosympodioides gen. nov.) on Brabejum stellatifolium, Sclerostagonospora ericae (on Erica sp.), Setophoma cyperi (on Cyperus sphaerocephala), and Phaeosphaeria breonadiae (on Breonadia microcephala). Novelties described from Robben Island (South Africa) include Wojnowiciella cissampeli and Diaporthe cissampeli (both on Cissampelos capensis), Phaeotheca salicorniae (on Salicornia meyeriana), Paracylindrocarpon aloicola (incl. Paracylindrocarpon gen. nov.) on Aloe sp., and Libertasomyces myopori (incl. Libertasomyces gen. nov.) on Myoporum serratum. Several novelties are recorded from La Réunion (France), namely Phaeosphaeriopsis agapanthi (on Agapanthus sp.), Roussoella solani (on Solanum mauritianum), Vermiculariopsiella acaciae (on Acacia heterophylla), Dothiorella acacicola (on Acacia mearnsii), Chalara clidemiae (on Clidemia hirta), Cytospora tibouchinae (on Tibouchina semidecandra), Diaporthe ocoteae (on Ocotea obtusata), Castanediella eucalypticola, Phaeophleospora eucalypticola and Fusicladium eucalypticola (on Eucalyptus robusta), Lareunionomyces syzygii (incl. Lareunionomyces gen. nov.) and Parawiesneriomyces syzygii (incl. Parawiesneriomyces gen. nov.) on leaves of Syzygium jambos. Novel taxa from the USA include Meristemomyces arctostaphylos (on Arctostaphylos patula), Ochroconis dracaenae (on Dracaena reflexa), Rasamsonia columbiensis (air of a hotel conference room), Paecilomyces tabacinus (on Nicotiana tabacum), Toxicocladosporium hominis (from human broncoalveolar lavage fluid), Nothophoma macrospora (from respiratory secretion of a patient with pneumonia), and Penidiellopsis radicularis (incl. Penidiellopsis gen. nov.) from a human nail. Novel taxa described from Malaysia include Prosopidicola albizziae (on Albizzia falcataria), Proxipyricularia asari (on Asarum sp.), Diaporthe passifloricola (on Passiflora foetida), Paramycoleptodiscus albizziae (incl. Paramycoleptodiscus gen. nov.) on Albizzia falcataria, and Malaysiasca phaii (incl. Malaysiasca gen. nov.) on Phaius reflexipetalus. Two species are newly described from human patients in the Czech Republic, namely Microascus longicollis (from toenails of patient with suspected onychomycosis), and Chrysosporium echinulatum (from sole skin of patient). Furthermore, Alternaria quercicola is described on leaves of Quercus brantii (Iran), Stemphylium beticola on leaves of Beta vulgaris (The Netherlands), Scleroderma capeverdeanum on soil (Cape Verde Islands), Scleroderma dunensis on soil, and Blastobotrys meliponae from bee honey (Brazil), Ganoderma mbrekobenum on angiosperms (Ghana), Geoglossum raitviirii and Entoloma kruticianum on soil (Russia), Priceomyces vitoshaensis on Pterostichus melas (Carabidae) (Bulgaria) is the only one for which the family is listed, Ganoderma ecuadoriense on decaying wood (Ecuador), Thyrostroma cornicola on Cornus officinalis (Korea), Cercophora vinosa on decorticated branch of Salix sp. (France), Coprinus pinetorum, Coprinus littoralis and Xerocomellus poederi on soil (Spain). Two new genera from Colombia include Helminthosporiella and Uwemyces on leaves of Elaeis oleifera. Two species are described from India, namely Russula intervenosa (ectomycorrhizal with Shorea robusta), and Crinipellis odorata (on bark of Mytragyna parviflora). Novelties from Thailand include Cyphellophora gamsii (on leaf litter), Pisolithus aureosericeus and Corynascus citrinus (on soil). Two species are newly described from Citrus in Italy, namely Dendryphiella paravinosa on Citrus sinensis, and Ramularia citricola on Citrus floridana. Morphological and culture characteristics along with ITS nrDNA barcodes are provided for all taxa.

Novel species of fungi described in this study include those from various countries as follows:Australia,Chaetopsina eucalyptionEucalyptusleaf litter,Colletotrichum cobbittiensefromCordyline stricta×C. australishybrid,Cyanodermella banksiaeonBanksia ericifoliasubsp.macrantha, Discosia macrozamiaeonMacrozamia miquelii, Elsinoë banksiigenaonBanksia marginata, Elsinoë elaeocarpionElaeocarpussp.,Elsinoë leucopogonisonLeucopogonsp.,Helminthosporium livistonaeonLivistona australis,Idriellomyces eucalypti(incl.Idriellomycesgen. nov.) onEucalyptus obliqua,Lareunionomyces eucalyptionEucalyptussp.,Myrotheciomyces corymbiae(incl.Myrotheciomycesgen. nov.,Myrotheciomycetaceaefam. nov.),Neolauriomyces eucalypti(incl.Neolauriomycesgen. nov.,Neolauriomycetaceaefam. nov.) onEucalyptussp.,Nullicamyces eucalypti(incl.Nullicamycesgen. nov.) onEucalyptusleaf litter,Oidiodendron eucalyptionEucalyptus maidenii,Paracladophialophora cyperacearum(incl.Paracladophialophoraceaefam. nov.) andPericonia cyperacearumon leaves ofCyperaceae,Porodiplodia livistonae(incl.Porodiplodiagen. nov.,Porodiplodiaceaefam. nov.) onLivistona australis,Sporidesmium melaleucae(incl.Sporidesmialesord. nov.) onMelaleucasp.,Teratosphaeria sieberionEucalyptus sieberi,Thecaphora australiensisin capsules of a variant ofOxalis exilis.Brazil,Aspergillus serratalhadensisfrom soil,Diaporthe pseudoinconspicuafromPoincianella pyramidalis,Fomitiporella pertenuison dead wood,Geastrum magnosporumon soil,Marquesius aquaticus(incl.Marquesiusgen. nov.) from submerged decaying twig and leaves of unidentified plant,Mastigosporella pigmentatafrom leaves ofQualea parviflorae,Mucor souzaefrom soil,Mycocalia aquaphilaon decaying wood from tidal detritus,Preussia citrullinaas endophyte from leaves ofCitrullus lanatus,Queiroziella brasiliensis(incl.Queiroziellagen. nov.) as epiphytic yeast on leaves ofPortea leptantha,Quixadomyces cearensis(incl.Quixadomycesgen. nov.) on decaying bark,Xylophallus clavatuson rotten wood.Canada,Didymella carionCarum carviandCoriandrum sativum.Chile,Araucasphaeria foliorum(incl.Araucasphaeriagen. nov.) onAraucaria araucana,Aspergillus tumidusfrom soil,Lomentospora valparaisensisfrom soil.Colombia,Corynespora pseudocassiicolaonByrsonimasp.,Eucalyptostroma eucalyptorumonEucalyptus pellita,Neometulocladosporiella eucalypti(incl.Neometulocladosporiellagen. nov.) onEucalyptus grandis×urophylla,Tracylla eucalypti(incl.Tracyllaceaefam. nov.,Tracyllalalesord. nov.) onEucalyptus urophylla.Cyprus,Gyromitra anthracobia(incl.Gyromitrasubg.Pseudoverpa) on burned soil.Czech Republic,Lecanicillium restrictumfrom the surface of the wooden barrel,Lecanicillium testudineumfromscales ofTrachemys scripta elegans.Ecuador,Entoloma yanacolorandSaproamanita quitensison soil.France,Lentithecium carbonneanumfrom submerged decorticatedPopulusbranch.Hungary,Pleuromyces hungaricus(incl.Pleuromycesgen. nov.) from a largeFagus sylvaticalog.Iran,Zymoseptoria crescentaonAegilops triuncialis.Malaysia,Ochroconis musicolaonMusasp.Mexico,Cladosporium michoacanensefrom soil.New Zealand, Acrodontium metrosiderionMetrosideros excelsa, Polynema podocarpionPodocarpus totara, Pseudoarthrographis phlogis(incl.Pseudoarthrographisgen. nov.) onPhlox subulata.Nigeria,Coprinopsis afrocinereaon soil.Pakistan,Russula mansehraensison soil underPinus roxburghii.Russia,Baorangia alexandrion soil in deciduous forests withQuercus mongolica.South Africa,Didymocyrtis brachylaenaeonBrachylaena discolor.Spain,Alfaria dactylisfrom fruit ofPhoenix dactylifera, Dothiora infuscansfrom a blackened wall,Exophiala nidicolafrom the nest of an unidentified bird,Matsushimaea monilioidesfrom soil,Terfezia morenoion soil.United Arab Emirates,Tirmania honrubiaeon soil.USA,Arxotrichum wyomingense(incl.Arxotrichumgen. nov.) from soil,Hongkongmyces snookiorumfrom submerged detritus from a fresh water fen,Leratiomyces tesquorumfrom soil,Talaromyces tabacinusonleaves ofNicotiana tabacum.Vietnam,Afroboletus vietnamensison soil in an evergreen tropical forest,Colletotrichum condaoensefromIpomoea pes-caprae.Morphological and culture characteristics along with DNA barcodes are provided.

Novel species of fungi described in the present study include the following from Australia: Neoseptorioides eucalypti gen. & sp. nov. from Eucalyptus radiata leaves, Phytophthora gondwanensis from soil, Diaporthe tulliensis from rotted stem ends of Theobroma cacao fruit, Diaporthe vawdreyi from fruit rot of Psidium guajava, Magnaporthiopsis agrostidis from rotted roots of Agrostis stolonifera and Semifissispora natalis from Eucalyptus leaf litter. Furthermore, Neopestalotiopsis egyptiaca is described from Mangifera indica leaves (Egypt), Roussoella mexicana from Coffea arabica leaves (Mexico), Calonectria monticola from soil (Thailand), Hygrocybe jackmanii from littoral sand dunes (Canada), Lindgomyces madisonensis from submerged decorticated wood (USA), Neofabraea brasiliensis from Malus domestica (Brazil), Geastrum diosiae from litter (Argentina), Ganoderma wiiroense on angiosperms (Ghana), Arthrinium gutiae from the gut of a grasshopper (India), Pyrenochaeta telephoni from the screen of a mobile phone (India) and Xenoleptographium phialoconidium gen. & sp. nov. on exposed xylem tissues of Gmelina arborea (Indonesia). Several novelties are introduced from Spain, namely Psathyrella complutensis on loamy soil, Chlorophyllum lusitanicum on nitrified grasslands (incl. Chlorophyllum arizonicum comb. nov.), Aspergillus citocrescens from cave sediment and Lotinia verna gen. & sp. nov. from muddy soil. Novel foliicolous taxa from South Africa include Phyllosticta carissicola from Carissa macrocarpa, Pseudopyricularia hagahagae from Cyperaceae and Zeloasperisporium searsiae from Searsia chirindensis. Furthermore, Neophaeococcomyces is introduced as a novel genus, with two new combinations, N. aloes and N. catenatus. Several foliicolous novelties are recorded from La Réunion, France, namely Ochroconis pandanicola from Pandanus utilis, Neosulcatispora agaves gen. & sp. nov. from Agave vera-cruz, Pilidium eucalyptorum from Eucalyptus robusta, Strelitziana syzygii from Syzygium jambos (incl. Strelitzianaceae fam. nov.) and Pseudobeltrania ocoteae from Ocotea obtusata (Beltraniaceae emend.). Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.

Novel species of fungi described in this study include those from various countries as follows: Australia: Banksiophoma australiensis (incl. Banksiophoma gen. nov.) on Banksia coccinea, Davidiellomyces australiensis (incl. Davidiellomyces gen. nov.) on Cyperaceae, Didymocyrtis banksiae on Banksia sessilis var. cygnorum, Disculoides calophyllae on Corymbia calophylla, Harknessia banksiae on Banksia sessilis, Harknessia banksiae-repens on Banksia repens, Harknessia banksiigena on Banksia sessilis var. cygnorum, Harknessia communis on Podocarpus sp., Harknessia platyphyllae on Eucalyptus platyphylla, Myrtacremonium eucalypti (incl. Myrtacremonium gen. nov.) on Eucalyptus globulus, Myrtapenidiella balenae on Eucalyptus sp., Myrtapenidiella eucalyptigena on Eucalyptus sp., Myrtapenidiella pleurocarpae on Eucalyptus pleurocarpa, Paraconiothyrium hakeae on Hakea sp., Paraphaeosphaeria xanthorrhoeae on Xanthorrhoea sp., Parateratosphaeria stirlingiae on Stirlingia sp., Perthomyces podocarpi (incl. Perthomyces gen. nov.) on Podocarpus sp., Readeriella ellipsoidea on Eucalyptus sp., Rosellinia australiensis on Banksia grandis, Tiarosporella corymbiae on Corymbia calophylla, Verrucoconiothyrium eucalyptigenum on Eucalyptus sp., Zasmidium commune on Xanthorrhoea sp., and Zasmidium podocarpi on Podocarpus sp. Brazil: Cyathus aurantogriseocarpus on decaying wood, Perenniporia brasiliensis on decayed wood, Perenniporia paraguyanensis on decayed wood, and Pseudocercospora leandrae-fragilis on Leandra fragilis. Chile: Phialocephala cladophialophoroides on human toe nail. Costa Rica: Psathyrella striatoannulata from soil. Czech Republic: Myotisia cremea (incl. Myotisia gen. nov.) on bat droppings. Ecuador: Humidicutis dictiocephala from soil, Hygrocybe macrosiparia from soil, Hygrocybe sangayensis from soil, and Polycephalomyces onorei on stem of Etlingera sp. France: Westerdykella centenaria from soil. Hungary: Tuber magentipunctatum from soil. India: Ganoderma mizoramense on decaying wood, Hodophilus indicus from soil, Keratinophyton turgidum in soil, and Russula arunii on Pterigota alata. Italy: Rhodocybe matesina from soil. Malaysia: Apoharknessia eucalyptorum, Harknessia malayensis, Harknessia pellitae, and Peyronellaea eucalypti on Eucalyptus pellita, Lectera capsici on Capsicum annuum, and Wallrothiella gmelinae on Gmelina arborea. Morocco: Neocordana musigena on Musa sp. New Zealand: Candida rongomai-pounamu on agaric mushroom surface, Candida vespimorsuum on cup fungus surface, Cylindrocladiella vitis on Vitis vinifera, Foliocryphia eucalyptorum on Eucalyptus sp., Ramularia vacciniicola on Vaccinium sp., and Rhodotorula ngohengohe on bird feather surface. Poland: Tolypocladium fumosum on a caterpillar case of unidentified Lepidoptera. Russia: Pholiotina longistipitata among moss. Spain: Coprinopsis pseudomarcescibilis from soil, Eremiomyces innocentii from soil, Gyroporus pseudocyanescens in humus, Inocybe parvicystis in humus, and Penicillium parvofructum from soil. Unknown origin: Paraphoma rhaphiolepidis on Rhaphiolepsis indica. USA: Acidiella americana from wall of a cooling tower, Neodactylaria obpyriformis (incl. Neodactylaria gen. nov.) from human bronchoalveolar lavage, and Saksenaea loutrophoriformis from human eye. Vietnam: Phytophthora mekongensis from Citrus grandis, and Phytophthora prodigiosa from Citrus grandis. Morphological and culture characteristics along with DNA barcodes are provided.

Symbioses are increasingly seen as dynamic ecosystems with multiple associates and varying fidelity. Symbiont specificity remains elusive in one of the most ecologically successful and economically damaging eukaryotic symbioses: the ambrosia symbiosis of wood-boring beetles and fungi. We used multiplexed pyrosequencing of amplified internal transcribed spacer II (ITS2) ribosomal DNA (rDNA) libraries to document the communities of fungal associates and symbionts inside the mycangia (fungus transfer organ) of three ambrosia beetle species, Xyleborus affinis, Xyleborus ferrugineus and Xylosandrus crassiusculus. We processed 93 beetle samples from 5 locations across Florida, including reference communities. Fungal communities within mycangia included 14–20 fungus species, many more than reported by culture-based studies. We recovered previously known nutritional symbionts as members of the core community. We also detected several other fungal taxa that are equally frequent but whose function is unknown and many other transient species. The composition of fungal assemblages was significantly correlated with beetle species but not with locality. The type of mycangium appears to determine specificity: two Xyleborus with mandibular mycangia had multiple dominant associates with even abundances; Xylosandrus crassiusculus (mesonotal mycangium) communities were dominated by a single symbiont, Ambrosiella sp. Beetle mycangia also carried many fungi from the environment, including plant pathogens and endophytes. The ITS2 marker proved useful for ecological analyses, but the taxonomic resolution was limited to fungal genus or family, particularly in Ophiostomatales, which are under-represented in our amplicons as well as in public databases. This initial analysis of three beetle species suggests that each clade of ambrosia beetles and each mycangium type may support a functionally and taxonomically distinct symbiosis.