Dynamics and drivers of fungal communities in a multipartite ant-plant association.

BACKGROUND: Fungi and ants belong to the most important organisms in terrestrial ecosystems on Earth. In nutrient-poor niches of tropical rainforests, they have developed steady ecological relationships as a successful survival strategy. In tropical ant-plant mutualisms worldwide, where resident ants provide the host plants with defense and nutrients in exchange for shelter and food, fungi are regularly found in the ant nesting space, inhabiting ant-made dark-colored piles ("patches"). Unlike the extensively investigated fungus-growing insects, where the fungi serve as the primary food source, the purpose of this ant-fungi association is less clear. To decipher the roles of fungi in these structures within ant nests, it is crucial to first understand the dynamics and drivers that influence fungal patch communities during ant colony development. RESULTS: In this study, we investigated how the ant colony age and the ant-plant species affect the fungal community in the patches. As model we selected one of the most common mutualisms in the Tropics of America, the Azteca-Cecropia complex. By amplicon sequencing of the internal transcribed spacer 2 (ITS2) region, we analyzed the patch fungal communities of 93 Azteca spp. colonies inhabiting Cecropia spp. trees. Our study demonstrates that the fungal diversity in patches increases as the ant colony grows and that a change in the prevalent fungal taxa occurs between initial and established patches. In addition, the ant species significantly influences the composition of the fungal community in established ant colonies, rather than the host plant species. CONCLUSIONS: The fungal patch communities become more complex as the ant colony develops, due to an acquisition of fungi from the environment and a substrate diversification. Our results suggest a successional progression of the fungal communities in the patches during ant colony growth and place the ant colony as the main driver shaping such communities. The findings of this study demonstrate the unexpectedly complex nature of ant-plant mutualisms in tropical regions at a micro scale.

Exo- and endophytic fungi enable rapid transfer of nutrients from ant waste to orchid tissue.

The epiphytic orchid Caularthron bilamellatum sacrifices its water storage tissue for nutrients from the waste of ants lodging inside its hollow pseudobulb. Here, we investigate whether fungi are involved in the rapid translocation of nutrients. Uptake was analysed with a 15 N labelling experiment, subsequent isotope ratio mass spectrometry (IRMS) and secondary ion mass spectrometry (ToF-SIMS and NanoSIMS). We encountered two hyphae types: a thick melanized type assigned to 'black fungi' (Chaetothyriales, Cladosporiales, and Mycosphaerellales) in ant waste, and a thin endophytic type belonging to Hypocreales. In few cell layers, both hyphae types co-occurred. 15 N accumulation in both hyphae types was conspicuous, while for translocation to the vessels only Hypocreales were involved. There is evidence that the occurrence of the two hyphae types results in a synergism in terms of nutrient uptake. Our study provides the first evidence that a pseudobulb (=stem)-born endophytic network of Hypocreales is involved in the rapid translocation of nitrogen from insect-derived waste to the vegetative and reproductive tissue of the host orchid. For C. bilamellatum that has no contact with the soil, ant waste in the hollow pseudobulbs serves as equivalent to soil in terms of nutrient sources.

Molecular phylogeny and a new Iranian species of Caudospora (Sydowiellaceae, Diaporthales).

For the first time, molecular phylogenetic data on the peculiar diaporthalean genus Caudospora are available. Macro- and microscopic morphology and phylogenetic multilocus analyses of partial nuc SSU-ITS-LSU rDNA, cal, ms204, rpb1, rpb2, tef1 and tub2 sequences revealed two distinct species of Caudospora, which are described and illustrated by light and scanning electron microscopy. Caudospora iranica is described as a new species from corticated dead twigs of Quercus sp. collected in Iran. It differs from the generic type, C. taleola, mainly by coarsely verrucose ascospores. The asexual morph of C. taleola on natural substrate is described and illustrated. Caudospora taleola is neotypified, and it is recorded from Iran for the first time. Phylogenetic analyses of a multigene matrix containing a representative selection of Diaporthales from four loci (ITS, LSU rDNA, rpb2 and tef1) revealed a placement of Caudospora within Sydowiellaceae.

Two unusual new species of Pleosporales: Anteaglonium rubescens and Atrocalyx asturiensis.

Two new species of Pleosporales, Anteaglonium rubescens (Anteagloniaceae) and Atrocalyx asturiensis (Lophiotremataceae), are described. Phylogenetic placement was determined by combined analyses of a DNA data matrix containing ITS, LSU, SSU, rpb2, and tef1. Anteaglonium rubescens is a stromatic fungus characterized by brown didymospores disarticulating within asci, and by the production of a red-orange to pink pigment produced in nature and in artificial culture. Atrocalyx asturiensis has massive ascomatal crests and brown phragmospores.

A phylogenetic perspective on the association between ants (Hymenoptera: Formicidae) and black yeasts (Ascomycota: Chaetothyriales).

The frequency and the geographical extent of symbiotic associations between ants and fungi of the order Chaetothyriales have been highlighted only recently. Using a phylogenetic approach based on seven molecular markers, we showed that ant-associated Chaetothyriales are scattered through the phylogeny of this order. There was no clustering according to geographical origin or to the taxonomy of the ant host. However, strains tended to be clustered according to the type of association with ants: strains from ant-made carton and strains from plant cavities occupied by ants ('domatia') rarely clustered together. Defining molecular operational taxonomic units (MOTUs) with an internal transcribed spacer sequence similarity cut-off of 99% revealed that a single MOTU could be composed of strains collected from various ant species and from several continents. Some ant-associated MOTUs also contained strains isolated from habitats other than ant-associated structures. Altogether, our results suggest that the degree of specialization of the interactions between ants and their fungal partners is highly variable. A better knowledge of the ecology of these interactions and a more comprehensive sampling of the fungal order are needed to elucidate the evolutionary history of mutualistic symbioses between ants and Chaetothyriales.

Three former taxa of Cucurbitaria and considerations on Petrakia in the Melanommataceae.

Based on phylogenetic analyses of an ITS-LSU-SSU-rpb2-tef1 sequence data matrix three taxa once classified in Cucurbitaria are referred to the Melanommataceae. Cucurbitaria rhododendri, also known as Melanomma rhododendri, is not congeneric with the generic type of Melanomma, M. pulvis-pyrius and thus classified in the new genus Alpinaria. Cucurbitaria piceae, known as Gemmamyces piceae, the cause of the Gemmamyces bud blight of Picea spp., belongs also to the Melanommataceae. The name Gemmamyces is conserved. For Cucurbitaria obducens, also known as Teichospora obducens, the new genus Praetumpfia is described, as it cannot be accommodated in any known genus. All species are redescribed and epitypified. Based on sequence data and morphology, Blastostroma, Mycodidymella and Xenostigmina are synonyms of Petrakia. The genus Petrakia is emended. We also provide sequences of additional markers for Beverwykella pulmonaria, Melanomma pulvis-pyrius, Petrakia echinata and Pseudotrichia mutabilis.

Stigmatodiscus pruni, a new dothideomycete with hysteriform ascomata.

Stigmatodiscus pruni (Stigmatodiscaceae, Stigmatodiscales) is described and illustrated from corticated dead twigs of Prunus spinosa collected in Austria and France. It is characterised by hysteriform ascomata with two lateral black lips, which are erumpent through the periderm of the host, and a black disc in combination with two-celled, asymmetric brown verruculose ascospores with a distinct sheath. Phylogenetic analyses of a multigene matrix containing a representative selection of Dothideomycetes from four genes (nuc 18S rDNA, nuc 28S rDNA, rpb2 and tef1) revealed a highly supported placement within Stigmatodiscales as sister species to Stigmatodiscus enigmaticus. Micromorphology of the sexual and asexual morph matches the genus Stigmatodiscus, except for the hysteriform shape of the ascomata and the two-celled ascospores.

Fungal Systematics and Evolution: FUSE 3.

The present study introduces seven new species, one new combination, one new variety and several interesting taxonomical notes and/or geographical records. Most of the new taxa are Ascomycetes, but the study also includes a new variety of a Basidiomycete. Novel species include Gyromitra khanspurensis (Discinaceae, Pezizales, Pezizomycetes) from Pakistan growing near Cedrus deoadara and Paramyrothecium guiyangense and Paramyrothecium verruridum (Stachybotriaceae, Hypocreales, Sordariomycetes) both isolated from soil in China. New species from South Africa are Sclerostagonospora elegiae on culm litter of Elegia equisetacea, Sclerostagonospora fusiformis on culm litter of Thamnochortus spicigerus, Sclerostagonospora pinguis on culm litter of Cannomois virgata and Sclerostagonospora sulcata on culm litter of Ischyrolepis subverticellata (Phaeosphaeriaceae, Pleosporales, Dothideomycetes). Hapalocystis berkeleyi var. kickxii with its basionym Hypoxylon kickxii is shown to be a taxon on species level and thus recombined as Hapalocystis kickxii (Sydowiellaceae, Diaporthales, Sordariomycetes), and it is lecto- and epitypified. The new variety Pluteus romellii var. luteoalbus (Pluteaceae, Agaricales, Agaricomycetes) growing on a mossy fallen stem of a deciduous tree is described from Czech Republic. Cortinarius scaurocaninus (Cortinariaceae, Agaricales, Agaricomycetes) is new for Austria, Humicola grisea (Chaetomiaceae, Sordariales, Sordariomycetes) is an interesting new record for Chile. Two taxa are reported as new for Turkey: the lichenicolous fungus Opegrapha parasitica (Opegraphaceae, Arthoniales, Arthoniomycetes) growing partly immersed in the thallus of Aspicilia and the lichen Rinodina zwackhiana (Physciaceae, Teloschistales, Lecanoromycetes) from calcareous rock. Finally, Xerula strigosa (Physalacriaceae, Agaricales, Agaricomycetes), described from China, is confirmed to be present also in Pakistan.

Asterodiscus and Stigmatodiscus, two new apothecial dothideomycete genera and the new order Stigmatodiscales.

During a survey on corticolous Dothideomycetes, several collections with ascospores matching the genera Asteromassaria and Stigmatomassaria (Pleomassariaceae, Pleosporales) were revealed from dead corticated twigs of Acer, Carpinus and Tamarix. Closer morphological examination showed that their ascomata were apothecial, with a hamathecium consisting of septate, branched paraphyses, which are apically swollen at maturity. Several collections were cultured and sequenced, and a Blast search of their nuc 28S rDNA sequences revealed dothideomycetous affiliation, but without a close match to a specific family or order. Phylogenetic analyses of a multigene matrix containing a representative selection of Dothideomycetes from four genes (nuc 18S rDNA, nuc 28S rDNA, rpb2 and tef1) revealed placement within Dothideomycetes but without a supported familial or ordinal affiliation. Based on the phylogenetic analyses and morphological investigations, the new genera Asterodiscus and Stigmatodiscus, with the two new species A. tamaricis and S. enigmaticus, are described and illustrated, and placed in the new family Stigmatodiscaceae and new order Stigmatodiscales.

Multi-locus tree and species tree approaches toward resolving a complex clade of downy mildews (Straminipila, Oomycota), including pathogens of beet and spinach.

Accurate species determination of plant pathogens is a prerequisite for their control and quarantine, and further for assessing their potential threat to crops. The family Peronosporaceae (Straminipila; Oomycota) consists of obligate biotrophic pathogens that cause downy mildew disease on angiosperms, including a large number of cultivated plants. In the largest downy mildew genus Peronospora, a phylogenetically complex clade includes the economically important downy mildew pathogens of spinach and beet, as well as the type species of the genus Peronospora. To resolve this complex clade at the species level and to infer evolutionary relationships among them, we used multi-locus phylogenetic analysis and species tree estimation. Both approaches discriminated all nine currently accepted species and revealed four previously unrecognized lineages, which are specific to a host genus or species. This is in line with a narrow species concept, i.e. that a downy mildew species is associated with only a particular host plant genus or species. Instead of applying the dubious name Peronospora farinosa, which has been proposed for formal rejection, our results provide strong evidence that Peronospora schachtii is an independent species from lineages on Atriplex and apparently occurs exclusively on Beta vulgaris. The members of the clade investigated, the Peronospora rumicis clade, associate with three different host plant families, Amaranthaceae, Caryophyllaceae, and Polygonaceae, suggesting that they may have speciated following at least two recent inter-family host shifts, rather than contemporary cospeciation with the host plants.

Two new species of Thyronectria from Mediterranean Europe.

Two new species of Thyronectria growing in Mediterranean vegetation are described from southern Spain; they are T. giennensis from Quercus ilex ssp. rotundifolia and T. pistaciae from Pistacia lentiscus. Both species are characterized by morphology of sexual and asexual morphs and by DNA data. They have olivaceous to green-brown muriform ascospores and are closely related to T. asturiensis and T. roseovirens, as determined by multigene phylogenetic analyses of a matrix containing six loci (ITS and 28S regions of nuc rDNA, ACT1, RPB1, RPB2, TEF1 and TUB2 genes). We also report that Cucurbitaria bicolor is a synonym of Thyronectria rhodochlora, the type species of Thyronectria.

Taxonomic position of the genus Bicornispora and the appearance of a new species Bicornispora seditiosa.

The discovery of a second species of Bicornispora in Spain, B. seditiosa, which is closely related to B. exophiala but has smaller ascospores, narrower asci and different ecology, gave us the opportunity to culture and sequence the fungus. Phylogenetic analyses of rDNA regions including partial nuc 28S rDNA (28S) and ITS1-5.8S-ITS2 (ITS) supported a close relationship with species of the genus Lambertella (Rutstroemiaceae), placing Bicornispora, previously ascribed to Coryneliales, within Helotiales. This result confirmed an evolutionary linkage between certain inoperculate discomycetes such as Lambertella palmeri and derived cleistothecial forms (Bicornispora spp.). Based on analyses of morphological study and molecular phylogenetic analyses, a new combination Rutstroemia asphodeli is proposed for Ciboria asphodeli.

Coupling Spore Traps and Quantitative PCR Assays for Detection of the Downy Mildew Pathogens of Spinach (Peronospora effusa) and Beet (P. schachtii).

Downy mildew of spinach (Spinacia oleracea), caused by Peronospora effusa, is a production constraint on production worldwide, including in California, where the majority of U.S. spinach is grown. The aim of this study was to develop a real-time quantitative polymerase chain reaction (qPCR) assay for detection of airborne inoculum of P. effusa in California. Among oomycete ribosomal DNA (rDNA) sequences examined for assay development, the highest nucleotide sequence identity was observed between rDNA sequences of P. effusa and P. schachtii, the cause of downy mildew on sugar beet and Swiss chard in the leaf beet group (Beta vulgaris subsp. vulgaris). Single-nucleotide polymorphisms were detected between P. effusa and P. schachtii in the 18S rDNA regions for design of P. effusa- and P. schachtii-specific TaqMan probes and reverse primers. An allele-specific probe and primer amplification method was applied to determine the frequency of both P. effusa and P. schachtii rDNA target sequences in pooled DNA samples, enabling quantification of rDNA of P. effusa from impaction spore trap samples collected from spinach production fields. The rDNA copy numbers of P. effusa were, on average, ≈3,300-fold higher from trap samples collected near an infected field compared with those levels recorded at a site without a nearby spinach field. In combination with disease-conducive weather forecasting, application of the assays may be helpful to time fungicide applications for disease management.

The rise and fall of Sarawakus (Hypocreaceae, Ascomycota).

Species of Sarawakus are rarely encountered. Their teleomorphs resemble sexual stages of Trichoderma, formerly called Hypocrea, but differ from that genus by unicellular ascospores. The two green-spored species S. britannicus and the type species of Sarawakus, S. lycogaloides, recently were collected, compared with their types and cultured. We redescribe and illustrate these species and transfer them to Trichoderma, based on phylogenetic analysis of the translation elongation factor 1-alpha encoding gene (tef1), containing the two last introns and exon, and a part of the rpb2 gene, encoding the second largest RNA polymerase subunit. Trichoderma lycogaloides, was found to cluster with Hypocrea sulawesensis, an unusual species of Trichoderma, while T. britannicum is closely related to T. aerugineum of the Spinulosa clade. The anamorphs of the two examined species are characterized by (odd) verticillium-like conidiophores, large cylindrical phialides and conidia, which belong to the largest of those species forming green conidia, oval to subglobose in T. lycogaloides and oblong in T. britannicum. All species currently recognized in Sarawakus are transferred to Trichoderma, introducing the new combinations T. fragile, T. hexasporum, T. izawae, T. sordidum, T. subtrachycarpum, T. succisum and T. trachycarpum and the new name T. rosellum. Trichoderma trachycarpum is redescribed and illustrated from an isotype.

Front line defenders of the ecological niche! Screening the structural diversity of peptaibiotics from saprotrophic and fungicolous Trichoderma/Hypocrea species.

Approximately 950 individual sequences of non-ribosomally biosynthesised peptides are produced by the genus Trichoderma/Hypocrea that belong to a perpetually growing class of mostly linear antibiotic oligopeptides, which are rich in the non-proteinogenic α-aminoisobutyric acid (Aib). Thus, they are comprehensively named peptaibiotics. Notably, peptaibiotics represent ca. 80 % of the total inventory of secondary metabolites currently known from Trichoderma/Hypocrea. Their unique membrane-modifying bioactivity results from amphipathicity and helicity, thus making them ideal candidates in assisting both colonisation and defence of the natural habitats by their fungal producers. Despite this, reports on the in vivo-detection of peptaibiotics have scarcely been published in the past. In order to evaluate the significance of peptaibiotic production for a broader range of potential producers, we screened nine specimens belonging to seven hitherto uninvestigated fungicolous or saprotrophic Trichoderma/Hypocrea species by liquid chromatography coupled to electrospray high resolution mass spectrometry. Sequences of peptaibiotics found were independently confirmed by analysing the peptaibiome of pure agar cultures obtained by single-ascospore isolation from the specimens. Of the nine species examined, five were screened positive for peptaibiotics. A total of 78 peptaibiotics were sequenced, 56 (=72 %) of which are new. Notably, dihydroxyphenylalaninol and O-prenylated tyrosinol, two C-terminal residues, which have not been reported for peptaibiotics before, were found as well as new and recurrent sequences carrying the recently described tyrosinol residue at their C-terminus. The majority of peptaibiotics sequenced are 18- or 19-residue peptaibols. Structural homologies with 'classical representatives' of subfamily 1 (SF1)-peptaibiotics argue for the formation of transmembrane ion channels, which are prone to facilitate the producer capture and defence of its substratum.

Bottlebrush and Myrtle twig canker caused by Neopestalotiopsis species: an emerging canker-causing group of fungi in Italy.

Pestalotioid fungi were isolated in pure culture from symptomatic plants of Callistemonlaevis, C.viminalis, Lumaapiculata (marketed as "Myrtusluma"), Myrtuscommunissubsp.tarentina, and M.communisvar.microphylla (M.communis 'Microphylla'), showing twig canker, dieback and defoliation. The isolates were identified to species by ITS, tef1 and tub2 sequences, which revealed the presence of six species of Neopestalotiopsis (N.camelliae-oleiferae, N.hispanica, N.iberica, N.rosae, N.rosicola, and N.zakeelii) and one species of Pestalotiopsis (P.biciliata). While most species were isolated only once or twice, the majority of isolates belonged to N.rosae (13) and N.hispanica (8). Pathogenicity was investigated by pathogenicity tests on all hosts, which confirmed the pathogenicity of all Neopestalotiopsis species on at least some of the hosts tested, while P.biciliata did not cause any disease symptoms. Neopestalotiopsishispanica and N.rosae caused symptoms in all hosts of the present study, while the other Neopestalotiopsis species tested showed no symptoms on Lumaapiculata.

Molecular systematics of Woswasia atropurpurea gen. et sp. nov. (Sordariomycetidae), a fungicolous ascomycete with globose ascospores and holoblastic conidiogenesis.

The monotypic genus Woswasia is described for wood-inhabiting and mycotrophic fungi classified in the Sordariomycetidae. It is characterized by unicellular, hyaline, globose to ellipsoid, verruculose ascospores; unitunicate long-stipitate asci with an apical annulus staining blue in aqueous cotton blue and perithecia with a long neck immersed in a stroma exhibiting a conspicuous pH-dependent color reaction. In vitro, it produces branched subhyaline to hyaline conidiophores with terminally arranged sympodial conidiogenous cells and holoblastic hyaline conidia. The remarkable morphological similarity of Woswasia to Amplistroma of the Amplistromataceae, although suggestive of a close relationship, was not confirmed by molecular data. Phylogenetic analysis based on two functional ribosomal genes (large and small subunits of the nuclear rDNA) and one protein-coding gene (second largest subunit of RNA polymerase II) supports the placement of Woswasia in the Sordariomycetidae incertae sedis. Woswasia atropurpurea, the type and only species of the genus, groups within a large heterogeneous clade containing other small or monotypic genera of wood-inhabiting saprobic fungi, which are distantly related and of which the majority lacks an ordinal or familial affiliation. Within the clade a relationship of Woswasia to the freshwater genus Cyanoannulus is suggested.

Screening the biosphere: the fungicolous fungus Trichoderma phellinicola, a prolific source of hypophellins, new 17-, 18-, 19-, and 20-residue peptaibiotics.

To investigate the significance of antibiotics for the producing organism(s) in the natural habitat, we screened a specimen of the fungicolous fungus Trichoderma phellinicola (syn. Hypocrea phellinicola) growing on its natural host Phellinus ferruginosus. Results revealed that a particular group of non-ribosomal antibiotic polypeptides, peptaibiotics, which contain the non-proteinogenic marker amino acid, α-aminoisobutyric acid, was biosynthesized in the natural habitat by the fungicolous producer and, consequently, released into the host. By means of liquid chromatography coupled to electrospray high-resolution time-of-flight mass spectrometry, we detected ten 20-residue peptaibols in the specimen. Sequences of peptaibiotics found in vivo were independently confirmed by analyzing the peptaibiome of an agar plate culture of T. phellinicola CBS 119283 (ex-type) grown under laboratory conditions. Notably, this strain could be identified as a potent producer of 39 new 17-, 18-, and 19-residue peptaibiotics, which display the same building scheme as the 20-residue peptaibols found in the specimen. Two of the 19-residue peptaibols are tentatively assigned to carry tyrosinol, a novel C-terminal residue, as deduced from high-resolution tandem mass-spectrometry data. For the new peptaibiotics produced by T. phellinicola, the name 'hypophellin(s)', based on the teleomorph name, is introduced.

New combinations in Trichoderma (Hypocreaceae, Hypocreales).

Unitary nomenclature demands the use of a single name for pleomorphic fungi determined according to priority. For this reason combinations in Trichoderma are here provided for 46 species for which such a combination is lacking. Although many more such species are known, only those are included here that are dealt with in more recent papers and where some DNA data are available in GenBank, even if erroneous; for other species it is strongly recommended to consult databases like Index Fungorum or MycoBank. Information on types is provided for most species, and representative cultures, GenBank accessions for tef1 and rpb2, and important references are given for all species.

Alien and cryptogenic fungi and oomycetes in Austria: an annotated checklist (2nd edition).

Fungal invasions can have far-reaching consequences, and despite increasing relevance, fungi are notoriously underrepresented in invasion science. Here, we present the second annotated checklist for alien and cryptogenic fungi and oomycetes in Austria. This list contains 375 taxa of which 278 are classified as established; compared to the first checklist from 2002, this amounts to an almost five-fold increase and the number of decade-wise first records is steadily rising since the mid-twentieth century. The introduction pathway is unclear for the vast majority of taxa, while the main means of spread within the country is unassisted secondary spread. Fungi were predominantly introduced from the Northern Hemisphere, especially North America and Temperate Asia. Rates of newly recorded alien fungi differ among phyla; the majority belongs to the Ascomycota, which experienced an 9.6-fold increase in numbers. Orders found most frequently are powdery mildews (Erysiphales, Ascomycota), downy mildews (Peronosporales, Oomycota), agarics (Agaricales, Basidiomycota), Mycosphaerellales (Ascomycota), rusts (Pucciniales, Basidiomycota) and Pleosporales (Ascomycota). The majority (about 80%) of the taxa are plant pathogens, while animal pathogens are few but severely affecting their native hosts. The dominance of pathogens in our checklist underlines the need of better tackling fungal invasions-especially in the light of emerging infectious diseases-and highlights potential knowledge gaps for ectomycorrhizal and saprobic alien fungi, whose invasion processes are often much more inconspicuous. Our results show that fungal invasions are a phenomenon of increasing importance, and collaborative efforts are needed for advancing the knowledge and management of this important group. Supplementary Information: The online version contains supplementary material available at 10.1007/s10530-022-02896-2.