Ondřej Koukol

Fungal Planet description sheets: 107–127

Novel species of microfungi described in the present study include the following from Australia: Phytophthora amnicola from still water, Gnomoniopsis smithogilvyi from Castanea sp., Pseudoplagiostoma corymbiae from Corymbia sp., Diaporthe eucalyptorum from Eucalyptus sp., Sporisorium andrewmitchellii from Enneapogon aff. lindleyanus, Myrmecridium banksiae from Banksia, and Pilidiella wangiensis from Eucalyptus sp. Several species are also described from South Africa, namely: Gondwanamyces wingfieldii from Protea caffra, Montagnula aloes from Aloe sp., Diaporthe canthii from Canthium inerne, Phyllosticta ericarum from Erica gracilis, Coleophoma proteae from Protea caffra, Toxicocladosporium strelitziae from Strelitzia reginae, and Devriesia agapanthi from Agapanthus africanus. Other species include Phytophthora asparagi from Asparagus officinalis (USA), and Diaporthe passiflorae from Passiflora edulis (South America). Furthermore, novel genera of coelomycetes include Chrysocrypta corymbiae from Corymbia sp. (Australia), Trinosporium guianense, isolated as a contaminant (French Guiana), and Xenosonderhenia syzygii, from Syzygium cordatum (South Africa). Pseudopenidiella piceae from Picea abies (Czech Republic), and Phaeocercospora colophospermi from Colophospermum mopane (South Africa) represent novel genera of hyphomycetes. Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.

Diversity of foliar endophytes in wind-fallen Picea abies trees

The unmanaged Norway spruce montane forests in the Bohemian Forest National Park (Czech Republic) suffered from repeated large-scale bark beetle outbreaks in last decade. In this study, the diversity of culturable foliar endophyte microfungi in needles originating from eleven recently wind-fallen trees in this area was surveyed. Our aims were to describe their diversity and to determine the relative host and organ specificities of isolated endophyte species to estimate the species pool and abundance of foliar endophytes before the forest degradation. Microfungi were isolated from surface-sterilized needles, and the outgrowing strains were identified based on morphological and molecular characteristics (analyses of ITS1, ITS2 and partial 28S rDNA). Fungal communities in the needles were diverse, with ascomycetes (mostly anamorphs of Helotiales) dominating basidiomycetes. The most frequent species (Phacidiopycnis sp., Cistella acuum, Sirococcus sp. and two species of Chalara) did not correspond with those recorded in previous studies of Picea spp. For example, the widely distributed Lophodermium piceae was rarely recorded in this study. This pattern may be caused by different methods of sterilization and cultivation or by physiological characteristics of the needles, or it may reflect the species distribution in the studied area. Members of the Helotiales, along with sequences from GenBank, showed substantial overlap in host affinities, most prominently between Pinus and Picea, and also among species from distant plant lineages.

Interactions Between Testate Amoebae and Saprotrophic Microfungi in a Scots Pine Litter Microcosm

In all terrestrial ecosystems, testate amoebae (TA) encounter fungi. There are strong indications that both groups engage in multiple interactions, including mycophagy and decomposition of TA shells, processes which might be fundamental in nutrient cycling in certain ecosystems. Here, we present the results of an experiment focusing on interactions between TA and saprotrophic microfungi colonizing Scots pine (Pinus sylvestris L.) litter needles. The needles were collected from a temperate pine forest and cultivated in damp chambers. Over a few weeks, melanized mycelium of Anavirga laxa Sutton started to grow out of some needles; simultaneously, the common forest-soil TA Phryganella acropodia (Hertwig and Lesser) Hopkinson reproduced and spread around the mycelium. We investigated whether a potential relationship between TA and saprotrophic microfungi exists by comparing the composition of TA communities on and around the needles and testing the spatial relationship between the A. laxa mycelium and P. acropodia shells in the experimental microcosm. Additionally, we asked whether P. acropodia utilized the A. laxa mycelium as a nutrient source and screened whether P. acropodia shells were colonized by the microfungi inhabiting the experimental microcosm. Our results indicate that saprotrophic microfungi may affect the composition of TA communities and their mycelium may affect distribution of TA individuals in pine litter. Our observations suggest that P. acropodia did not graze directly on A. laxa mycelium, but rather fed on its exudates or bacteria associated with the exudates. The fungus Pochonia bulbillosa (Gams & Malla) Zare & Gams was often found parasitising encysted shells or decomposing already dead individuals of P. acropodia. TA and pine litter microfungi engage in various direct and indirect interactions which are still poorly understood and deserve further investigation. Their elucidation will improve our knowledge on fundamental processes influencing coexistence of soil microflora and microfauna.

New species of Chalara occupying coniferous needles

Chalara is a genus of anamorphic fungi with typical phialidic conidiogenous cells. Species of Chalara live mostly as litter saprotrophs, many of them on coniferous litter. In this study, the morphology and DNA sequences (ITS rDNA, 28S rDNA and EF-1α) of strains of various species of Chalara isolated from coniferous litter needles were compared with those of strains from public collections. The majority of the isolates belonged to the C. longipes. Other strains represent C. piceae-abietis, C. microspora, C. microchona and four hitherto undescribed species. These are introduced here as C. holubovae sp. nov., C. hyalocuspica sp. nov., C. pseudoaffinis sp. nov. and C. recta sp. nov. Chalara recta is most closely related to C. longipes, which was found to be paraphyletic. However, no correlation of molecular data with the morphology was found. Chalara holubovae is specific among the Chalara species in that it has a synanamorph with fusiform conidia. Together with C. hyalocuspica, C. holubovae likely belong to the anamorphic Hyaloscyphaceae. Chalara piceae-abietis is epitypified. Epitypicifation of C. longipes and C. microspora cannot be done due to absence of a convenient specimen. Chalara austriaca may be re-discovered also after a targeted sampling in the locality of the type specimen. The majority of studied species are saprotrophic and colonise litter needles. An endophytic phase in living needles or other parts of a tree was confirmed for the species C. longipes and C. hyalocuspica. C. holubovae has been recorded only as an endophyte.

The diversity of oomycetes on crayfish: Morphological vs. molecular identification of cultures obtained while isolating the crayfish plague pathogen

Numerous oomycetes colonise the crayfish cuticle, the best known being the crayfish plague pathogen Aphanomyces astaci. Although other oomycetes associated with crayfish complicate the isolation and molecular detection of A. astaci, their diversity is little known. To improve this knowledge, we analysed 95 oomycete isolates obtained during attempts to isolate A. astaci from crayfish presumably infected by this pathogen. We characterized the isolates morphologically and by sequencing of the nuclear internal transcribed spacer (ITS) region. We identified 13 taxa by molecular analysis. Ten of them were assigned to five genera; the remaining three were affiliated with the order Saprolegniales but could not be reliably assigned to any genus. Morphological identification to species level was only possible for 15 % of isolates; all corresponded to Saprolegnia ferax, which was confirmed by ITS sequencing. The most frequently isolated species were S. ferax and Saprolegnia australis. Only seven isolates of A. astaci were obtained, all from one disease outbreak. We show that oomycete cultures obtained as by-products of parasite isolation are valuable for oomycete diversity studies, but morphological identification may uncover only a fraction of their diversity. Further, we show that crayfish may be frequently associated with potentially serious parasites of other organisms.

Revision of “Septonema ochraceum” revealed three new species of Venturiaceae and Herpotrichiellaceae

Survey of seven strains determined as Septonema ochraceum (Dothideomycetes, inc. sed.) isolated from pine litter or obtained from public collections revealed three new species, Fusicladium cordae, F. sicilianum (Venturiaceae), Cladophialophora matsushimae (Herpotrichiellaceae) and a cryptic species morphologically identical to Devriesia americana (Teratosphaeriaceae), but phylogenetically distinct. Morphological survey and phylogenetic analysis using nucleotide sequence data from the nuclear ribosomal subunit genes indicate a close relationship within three species colonising pine litter needles, F. cordae, F. pini and F. ramoconidii. F. sicilianum is most related to F. rhodense. C. matsushimae represents a species belonging to one of the lineages of the polyphyletic genus Cladophialophora. None of the strains observed can be classified morphologically as S. ochraceum, of which the type material does not exist.

Unseen, but still present in Czechia: Hymenoscyphus albidus detected by real-time PCR, but not by intensive sampling

The native European saprotrophic species Hymenoscyphus albidus seems to be replaced in the recent decade by a closely related, but invasive parasite of ash trees, H. fraxineus. Both species colonize the same niche, fallen petioles of ash leaves. In our study, we aimed at current distribution of H. fraxineus and attempted to find also H. albidus in Czechia. A revision of herbarium material based on molecular data confirmed the past presence of H. albidus in Czechia. Repeated attempts to rediscover H. albidus at four historical localities together with further 87 localities were unsuccessful. However, results of a targeted detection of H. albidus at four different localities using species-specific real-time PCR showed low, but constant presence of H. albidus ascospores. Therefore, H. albidus is not replaced by H. fraxineus, but these two species obviously coexist. Additionally, Cyathicula fraxinophila, another helotialean species commonly colonizing and specific to decaying ash petioles, seems to be unaffected by the spread of H. fraxineus and was present at 21 localities (at nine localities together with H. fraxineus, usually even on the same petioles). Another closely related, but plurivorous species on herbaceous stems, C. coronata, was recorded at five localities on ash petioles. Our results show that helotialean fungi colonizing ash petioles do not appear to be critically affected by the invasion of H. fraxineus.

Decomposition of spruce litter needles of different quality by Setulipes androsaceus and Thysanophora penicillioides

Various biotic and abiotic factors may change the quality of cast spruce needles or induce premature casting, subsequently altering the composition of needle litter. We tested the decomposition efficiency of Setulipes androsaceus, a key litter decomposer in spruce forests, on needles of the Norway spruce (Picea abies) that fell into three different categories of quality. We designed a cultivation experiment to test the decomposition rate of the following needle categories: (1) naturally senesced brown needles, (2) intact, prematurely fallen green needles, and (3) frass pellets produced by caterpillars of the spruce web-spinning sawfly (Cephalcia spp.). Needles from each category were cultivated both independently and in combination. After a 4-month incubation, dry weight loss and the decrease of p-hydroxyacetophenone (p-HAP) and catechin were measured as markers of decomposition. Colonization of green needles by mycelia of S. androsaceus was initially inhibited. However, within the experimental period, those green needles successfully colonized by S. androsaceus lost more mass (22% of dry weight) than the brown needles (18% of dry weight). S. androsaceus also decreased the p-HAP and catechin contents of the green needles. Another fungal decomposer, Thysanophora penicillioides, was introduced only to the treatment that contained all three needle categories, and it induced less weight loss than S. androsaceus, but degraded the two phenolics to a similar extent. Neither the green nor the brown needles exhibited a more rapid rate of decomposition when cultivated in combination with another category of needles. We conclude that the increased proportions of green needles and frass pellets in the litter will be connected with temporarily increased decomposition activity of S. androsaceus.

A new species of Lophodermium on needles of mountain pine ( Pinus mugo ) from the Giant Mountains in Poland

A fungus tentatively identified as Lophodermium sp. was repeatedly isolated from living secondary needles of mountain pine (Pinus mugo) in the Giant Mountains of Poland. Needles showed symptoms of yellow spots, gradual discolouration and premature falling in July. Thin black zone lines, subepidermal conidiomata and partially subepidermal ascomata morphologically similar to L. pinastri occurred on fallen needles in litter below the same trees. Evidence from internal transcribed spacers of rDNA and the gene for actin showed that strains isolated from symptom-bearing needles and fruiting structures were identical, and differed from other Lophodermium species known from pine, including L. pinastri. The fungus differs subtly from L. pinastri, for example, in the lengths of its conidiomata, ascomata and asci, but can be reliably distinguished only by molecular data. Known only on mountain pine from the Giant Mountains, it is described here as L. corconticum sp. nov.

Panama, a hot spot for Hermatomyces (Hermatomycetaceae, Pleosporales) with five new species, and a critical synopsis of the genus

Five new species belonging to Hermatomyces (Hermatomycetaceae, Pleosporales) are described based on morphological investigations of specimens collected on rotten twigs and stems of various plants in Panama as well as phylogenetic analyses of sequence data of nuclear ribosomal and protein coding genes (EF1-α, RPB2, β-TUB). The new species are described as: Hermatomyces bifurcatus, H. constrictus, H. megasporus, H. sphaericoides, and H. verrucosus spp. nov. Previously described species such as H. sphaericus and H. tucumanensis were identified among the studied specimens. The new combination, H. reticulatus, is made for Subicularium reticulatum based on examination of the holotype and fresh collections. Hermatomyces subiculosus, originally described from Thailand, is reduced to synonymy with H. reticulatus; H. tectonae is synonymized under H. sphaericus based on morphological and molecular evidence; and H. chiangmaiensis and H. thailandicus are considered later synonyms of H. krabiensis and H. indicus, respectively. The type material of Scyphostroma mirum was found to be conspecific with H. tucumanensis and, therefore, the generic name Hermatomyces should be conserved or protected against the older name Scyphostroma and the binomial H. tucumanensis against S. mirum. Sixteen species of Hermatomyces are recognized, their distinctive characteristics are highlighted in line drawings and a key is provided for their identification. The peculiar morphology and consistent phylogeny of new and previously known Hermatomyces species supports the recognition of the recently introduced monotypic family Hermatomycetaceae as a well delimited monophyletic taxon within the order Pleosporales.