Geosmithia Species Research Articles

Geosmithia tibetensis sp. nov. and new Gibellulopsis and Scopulariopsis records from Qinghai-Tibet

A new Geosmithia species and new records of Gibellulopsis nigrescens and Scopulariopsis canadensis are described and illustrated from the Qinghai-Tibet Plateau Area, China. Specimens (dried cultures) and living cultures are deposited in the Herbarium of Shandong Agricultural University, Plant Pathology (HSAUP). Duplicates are kept in the Herbarium of Institute of Microbiology, Academia Sinica (HMAS).

Vector Affinity and Diversity of Geosmithia Fungi Living on Subcortical Insects Inhabiting Pinaceae Species in Central and Northeastern Europe

Fungi from the genus Geosmithia (Ascomycota: Hypocreales) are associated with bark beetles (Coleoptera: Scolytinae), though little is known about ecology, diversity, and distribution of these fungi across beetle and its host tree species. This study surveyed the diversity, distribution and vector affinity of Geosmithia isolated from subcortical insects that colonized trees from the family Pinaceae in Central and Northeastern Europe. Twelve Geosmithia species were isolated from 85 plant samples associated with 23 subcortical insect species (including 14 bark beetle species). Geosmithia community composition was similar across different localities and vector species; although the fungal communities associated with insects that colonized Pinus differed from that colonizing other tree species (Abies, Larix, and Picea). Ten Geosmithia species from four independent phylogenetic lineages were not reported previously from vectors feeding on other plant families and seem to be restricted to the vectors from Pinaceae only. We conclude that presence of such substrate specificity suggests a long and stable association between Geosmithia and bark beetles.

Isolation and Identification of Geosmithia argillacea from a Fungal Ball in the Lung of a Tuberculosis Patient

Geosmithia argillacea, an anamorph of Talaromyces eburneus, is a thermophilic filamentous fungus that has a phenotype similar to that of the Penicillium species, except for the creamy-white colonies and cylindrical conidia. Recently, a new genus called Rasamsonia has been proposed, which is to accommodate the Talaromyces and Geosmithia species. Here, we report the first Korean case of G. argillacea isolated from a patient with a fungal ball. The patient was a 44-yr-old Korean man with a history of pulmonary tuberculosis and aspergilloma. The newly developed fungal ball in his lung was removed and cultured to identify the fungus. The fungal colonies were white and slow-growing, and the filaments resembled those of Penicillium. Molecular identification was carried out by sequencing the internal transcribed spacer (ITS) region of the 28S rDNA and the β-tubulin genes. A comparative sequence analysis using the GenBank (http://blast.ncbi.nlm.nih.gov/) database was performed with the basic local alignment search tool (BLAST) algorithm. The results revealed a 97-100% similarity with the G. argillacea ITS sequence. This case should increase awareness among physicians about the pathogenic potential of G. argillacea in humans and help them accurately identify this fungus, because it can be easily confused with Penicillium and Paecilomyces species owing to their similar phenotypic and microscopic characteristics. A molecular approach should be employed to enable accurate identification of G. argillacea.

Rasamsonia, a new genus comprising thermotolerant and thermophilic Talaromyces and Geosmithia species.

The phylogenetic relationship among Geosmithia argillacea, Talaromyces emersonii, Talaromyces byssochlamydoides and other members of the Trichocomaceae was studied using partial RPB2 (RNA polymerase II gene, encoding the second largest protein subunit), Tsr1 (putative ribosome biogenesis protein) and Cct8 (putative chaperonin complex component TCP-1) gene sequences. The results showed that these species form a distinct clade within the Trichocomaceae and Trichocoma paradoxa is phylogenetically most closely related. Based on phenotypic and physiological characters and molecular data, we propose Rasamsonia gen. nov. to accommodate these species. This new genus is distinct from other genera of the Trichocomaceae in being thermotolerant or thermophilic and having conidiophores with distinctly rough walled stipes, olive-brown conidia and ascomata, if present, with a scanty covering. Species within the genus Rasamsonia were distinguished using a combination of phenotypic characters, extrolite patterns, ITS and partial calmodulin and β-tubulin sequences. Rasamsonia brevistipitata sp. nov. is described and five new combinations are proposed.Electronic supplementary materialThe online version of this article (doi:10.1007/s10482-011-9647-1) contains supplementary material, which is available to authorized users.

Evidence for a new lineage of primary ambrosia fungi in Geosmithia Pitt (Ascomycota: Hypocreales)

Geosmithia is a genus of mitosporic filamentous fungi typically associated with phloeophagous bark beetles world-wide. During this study, the fungal associates of ambrosia beetles Cnesinus lecontei, Eupagiocerus dentipes, and Microcorthylus sp. from Costa Rica, were studied using morphology and DNA sequences. Fungal associates belonged to four undescribed Geosmithia species. Geosmithia eupagioceri sp. nov. and G. microcorthyli sp. nov. are evidently primary ambrosia fungi of their respective vectors E. dentipes and Microcorthylus species. They both have convergently evolved distinct morphological adaptations including the production of large, solitary and globose conidia, and yeast-like cells. Tunnels of C. lecontei contained an undescribed Geosmithia species, but its nutritional importance for its vector is unclear. An auxiliary ambrosia fungus, Geosmithia rufescens sp. nov., was found associated with both G. eupagioceri and the Geosmithia species associated with C. lecontei. G. microcorthyli is genetically quite similar to the phloem-associated Geosmithia sp. 8 from Europe. Large differences in morphology between these two species suggest the rapid co-evolution resulting from the close symbiosis of the former with its beetle host. The ITS rDNA sequences of G. microcorthyli and Geosmithia sp. 8 were not diagnostic, suggesting that alternative markers such as EF-1α, IGS rDNA or β-tubulin should be used, together with morphological and ecological data, for species delimitation in this genus. The primary ambrosia fungi described here are derived from phloem-associated ancestors, and represent two independent lineages of ambrosia fungi in the Hypocreales and a new ecological strategy within Geosmithia.

POTENTIAL IMPACTS OF THOUSAND CANKERS DISEASE ON COMMERCIAL WALNUT PRODUCTION AND WALNUT GERMPLASM CONSERVATION

Thousand cankers disease (TCD) is a recently identified insect/fungal disease complex responsible for mortality of eastern black walnut trees, Juglans nigra, planted in non-native areas of the western United States. The presence in California of both the insect vector, the walnut twig beetle, Pityophthorus juglandis, and the fungal pathogen, a species of Geosmithia, raises concerns regarding the potential impact of the disease on commercial walnut production and the long term health of other walnut species native to California and American Southwest. Movement of the disease eastward could threaten native J. nigra populations in hardwood forests of the eastern United States. Identification of both the vector and the fungal pathogen of TCD from trees in the USDA Germplasm Collection near Davis, CA may impact ex situ germplasm management.

Fungi associated with the fir bark beetle Cryphalus piceae in Poland

SummaryThe aim of this study was to identify fungi associated with Cryphalus piceae on European silver fir (Abies alba) in Poland and to test the pathogenicity of selected isolates. Fungi were isolated from five populations of overwintered adults and their galleries. A great diversity of taxa was associated with C. piceae. In total, 2487 isolates, including 58 species distributed in 25 genera, were obtained. The two most frequently isolated fungi, an undescribed species of the genus Geosmithia and Ophiostoma piceae, appeared to be specifically associated with C. piceae, whereas Pesotum fragrans, Pesotum sp. and Sporothrix sp. were sporadically associated. Two‐year‐old seedlings of silver fir were wound‐inoculated with three species of fungi (Geosmithia sp., O. piceae and Pesotum sp.) recovered from C. piceae. Only Pesotum sp. showed pathogenic ability, but we do not consider it to be an important pathogen of A. alba.

Hydroxylated anthraquinones produced by Geosmithia species

Geosmithia fungi are little known symbionts of bark beetles. Secondary metabolites of lilac colored species G. lavendula and other nine Geosmithia species were investigated in order to elucidate their possible role in the interactions of the fungi with environment. Hydroxylated anthraquinones (yellow, orange, and red pigments), were found to be the most abundant compounds produced into the medium during the submerged cultivation. Three main compounds were identified as 1,3,6,8-tetrahydroxyanthraquinone (1), rhodolamprometrin (1-acetyl-2,4,5,7-tetrahydroxyanthraquinone; 2), and 1-acetyl-2,4,5,7,8-pentahydroxyanthraquinone (3). Compounds 2 and 3 (representing the majority of produced metabolites) inhibited the growth of G+-bacteria Staphylococcus aureus and Bacillus subtilis with minimum inhibitory concentration of 64-512 microg/mL. Anti-inflammatory activity detected as inhibition of cyclooxygenase-2 was found only for compound 3 at 1 and 10 microg/mL. Compound 2 interfered with the morphology, compound 3 with cell-cycle dynamics of adherent mammalian cell lines.

Associations between Pityogenes bidentatus and fungi in young managed Scots pine stands in Poland

SummaryThe association between Pityogenes bidentatus and fungi was studied in young, managed Pinus sylvestris stands in Poland. Fungi were isolated from emerged adults and their galleries collected from four populations. In total, 2089 fungal isolates including 42 species, were obtained. Penicillium sp. 1 and Geosmithia sp. 1 were the most commonly isolated fungi from beetles (49% and 41% of beetles respectively). Geosmithia sp. 1 species was the dominant species in P. bidentatus galleries with a frequency of occurrence of 57.9%. Hormonema dematioides was the second most abundant fungus in gallery systems (17.1% of wood samples). Two of the isolated Geosmithia species were previously undescribed. Pityogenes bidentatus also vectored three ophiostomatoid species: Ophiostoma minus, O. piceae and Graphium sp. ‘W’. These species were occasionally isolated from beetles and their galleries, suggesting a non‐specific relationship.

Geosmithia Fungi are Highly Diverse and Consistent Bark Beetle Associates: Evidence from their Community Structure in Temperate Europe

Geosmithia spp. (Ascomycota: Hypocreales) are little-studied, dry-spored fungi that occur in galleries built by many phloeophagous bark beetles. This study mapped the distribution and environmental preferences of Geosmithia species occurring in galleries of temperate European bark beetles. One hundred seven host tree samples of 16 tree species infested with 23 subcortical insect species were collected from across Europe during the years 1997-2005. Over 600 Geosmithia isolates from the beetles were sorted into 17 operational taxonomic units (OTUs) based on their phenotype similarity and phylogeny of internal transcribed spacer (ITS) region of rDNA (ITS1-5.8S-ITS2). The OTUs represent six known species and eight undescribed taxa. Ninety-two samples infested with subcortical insects were characterized by the presence/absence of OTUs and the similarity among the samples was evaluated. Geographically distant populations of the same beetle species host relatively uniform Geosmithia communities across large geographic areas (ranging from southern Bulgaria to the Czech Republic). This suggests effective dispersal of Geosmithia spp. by bark beetles. Clustering of similar samples in ordination analysis is correlated predominantly with the isolation source (bark beetles and their respective feeding plant), but not with their geographical origin. The composition of the Geosmithia OTU community of each bark beetle species depends on the degree of isolation of the species' niches. Thus, Geosmithia communities associated with regularly co-occurring bark beetle species are highly similar. The similarity decreases with decreasing frequency of beetle species' co-occurrence, a pattern resembling that of entomochoric ophiostomatoid fungi. These findings suggest that: 1) communities of Geosmithia spp. are vector-specific; 2) at least in some cases, the association between Geosmithia OTUs and bark beetles may have been very stable and symbioses are likely to be a fundamental factor in the speciation of Geosmithia fungi; and 3) that even nonsticky spores of Geosmithia are suitable for maintaining an insect-fungus association, contrary to previous hypotheses.

A complex of three new white-spored, sympatric, and host range limited Geosmithia species

All hypocrealean species of the genus Geosmithia are anamorphic fungi with connections to bark beetles. G. fassatiae, G. langdonii and G. obscura are described as new sympatric species associated with Scolytus carpini, S. intricatus and S. rugulosus in Central Europe. The species represent a complex of three sister taxa with affinities to G. flava that may be distinguished by differences in morphology, unique RAPD patterns and by sequences of ITS region rDNA. Intraspecific variability and habitat specificity of new species is described and discussed. The high morphological, genetic and ecological uniformity suggest that these Geosmithia spp. are recently derived. A key to all accepted hypocrealean species of the genus is provided.

Cell wall polysaccharides F1SS disclose the relatedness of the genus Geosmithia with Eupenicillium and Talaromyces

Cell wall polysaccharides have been used as chemotaxonomic markers in a number of fungal genera. In this study, alkali-extractable and water-soluble cell wall polysaccharides F1SS were purified from cell walls of species of the genus Geosmithia. Chemical and 1H-NMR analyses of these polysaccharides revealed three different structures: (i) the polysaccharide from Geosmithia namylowskii was composed of β-(1[Formula: see text]5)-galactofuranose chains attached to an α-(1[Formula: see text]2)-(1[Formula: see text]6)-mannan core identical to that isolated in several species of Eupenicillium, (ii) the polysaccharide from Geosmithia viridis was a glucomannogalactan similar to that obtained in Talaromyces flavus, and (iii) the polysaccharide from Geosmithia putterillii contained β-(1[Formula: see text]5)-(1[Formula: see text]6)-galactofuranose with some units of the β-(1[Formula: see text]5) residues substituted at position O-6 by single residues of galactofuranose; this galactan was attached to an α-(1[Formula: see text]2)-(1[Formula: see text]6)-mannan core. The taxonomy of the genus is discussed according to the polysaccharides F1SS, and our results are compared with the results of rDNA analyses in this genus.Key words: Eurotiales, Geosmithia, Eupenicillium, Talaromyces, cell wall polysaccharides, chemotaxonomy.

Polyphyletic origins of species of the anamorphic genus Geosmithia and the relationships of the cleistothecial genera: Evidence from 18S, 5S and 28S rDNA sequence analyses

The anamorphic genus Geosmithia, with the type species G. lavendula, includes species strictly lacking a teleomorph as well as species associated with the teleomorphs Talaromyces and Chromocleista. Our 18S rDNA sequence-based tree, inferred from 1586 alignable sites from 57 selected taxa within the Ascomycota and using two basidiomycetes as out-groups, clearly demonstrates that Geosmithia is a polyphyletic taxon with evolutionary affinities to at least three groups of the euascomycete lineage within the Ascomycota: (1) Geosmithia lavendula, the type of the genus, G. putterilli, and the hypocrealean fungi, Gliodadium-producing Hypocrea lutea and Verticillium/Sepedonium-producing Hypomyces chrysogenum within the pyrenomycete lineage, appear as a monophyletic group with 100% bootstrap support; (2) G. cylindrospora and the Geosmithia-producing Talaromyces species (i.e., T. bacillisporus, T. ebruneus, and T. emerson- ii) group with the Penicillium-producing T. flavus var. macrosporus of the Trichocomaceae within the plectomycete lineage in 57% of bootstrap replicates; (3) G. namyslowskii, the Geosmithia-producing Chromocleista malachitea, the Penicillium-producing Eupenicillium crustaceum and the Merimbla-producing Talaromyces avellaneus (≡ Hamigera avellanea) of the same higher categories appear to be a monophyletic group in 74% of bootstrap replicates. The bootstrapped NJ and MP analyses, using 1706 sites of the same gene only from plectomycetes and pyrenomycetes, demonstrate similar phylogenetic relationships. The bootstrapped NJ and MP analyses, based on 70 alignable sites of 5S rDNA, support the results from 18S rDNA sequence analyses. Within the Hypocreales, G. lavendula and G. putterillii group with the hypocrealean fungi, cleistothecial, Acremonium-producing Mycoarachis inversa and Emericellopsis terricola, and the strictly anamorph species of Acremonium-in 66% or greater of the bootstrapped NJ and MP trees derived from 28S rDNA partial (580 sites) sequences. Phylogenetic considerations are also presented for several cleistothecial taxa.

Polyphyletic Origins of Species of the Anamorphic Genus Geosmithia and the Relationships of the Cleistothecial Genera: Evidence from 18S, 5S and 28S rDNA Sequence Analyses

Polyphyletic Origins of Species of the Anamorphic Genus Geosmithia and the Relationships of the Cleistothecial Genera: Evidence from 18S, 5S and 28S rDNA Sequence Analyses