The Genus Chlorosplenium (Helotiales, Leotiomycetes) from China with Notes on C. chlora Complex

The small fruitbodies of Chlorosplenium are greenish yellow and mainly grow on woody substrates. The species diversity of the genus in China was investigated based on specimens formerly deposited in the Herbarium Mycologicum Academiae Sinicae as well as new collections gained in recent years. Our phylogenetic results revealed the species diversity of the genus is underestimated and the commonly known Chlorosplenium chlora is a species complex. Based on morphology studies and sequence analyses of three regions (ITS, LSU and RPB1), the Chinese collections represent two new species which are described and illustrated here as C. sinicum and C. sinochlora. Chlorosplenium fusisporum is quite possibly a species of the genus Chlorociboria, and C. hyperici-maculati should be excluded from the genus.

Exploring the Ecomorphology of Two Cretaceous Enantiornithines With Unique Pedal Morphology

Recently, ∼100 Ma amber from Myanmar has become an important source of information regarding the morphology of Late Cretaceous enantiornithines. Two specimens consisting of partial hindlimbs exhibit unusual morphologies when compared to both extant avian taxa and other Cretaceous enantiornithines. Pedal morphology is extremely ecologically informative in Aves as it represents the interface between body and substrate. These seemingly bizarre pedal morphologies represent adaptations that allowed these birds to utilize certain niches present in their paleoenvironment. Specific ecological niches apply the same general pressures to different species over time, and in doing so, through natural selection, produce morphologies that function much the same, although they may be anatomically dissimilar. As such, extant animals can provide useful information pertaining to the functional morphology of extinct animals, even in the absence of direct analogs, as in the case of these two Hukawng enantiornithines. Comparisons to extant taxa in the same predicted niches of these enantiornithines can be used to either support or contradict previous hypotheses regarding the in vivo function of these unique pedal morphologies. Elektorornis chenguangi exhibits a hypertrophied third pedal digit, originally interpreted as an appendage used for probing. We support this interpretation, which allows informed speculation as to the cranial anatomy of this taxon since extant animals that probe in woody substrates consistently pair elongate probing structures with a second robust structure that functions as a means to penetrate into this hard substrate. This suggests that the rostrum of Elektorornis would have been robust and most likely edentulous. The second specimen YLSNHM01001 exhibits an unusually mediolaterally robust fourth pedal digit, nearly double the width of digit II. Given that no such morphology is present in any other bird in the Mesozoic or Cenozoic we feel the unusual morphology justifies erection of a new taxon, Fortipesavis prehendens gen. et sp. nov. Although distinct, the morphology in F. prehendens resembles the syndactyl condition in some extant avian groups, and we hypothesize the robust digit similarly functioned to increase the surface area of the foot, facilitating grip on perches through increased friction. The necessity for increased grip and the lateral placement of this digit may suggest F. prehendens utilized mobile perches similar to extant kingfishers.

Niche differentiation and evolution of the wood decay machinery in the invasive fungus Serpula lacrymans

Ecological niche breadth and the mechanisms facilitating its evolution are fundamental to understanding adaptation to changing environments, persistence of generalist and specialist lineages and the formation of new species. Woody substrates are structurally complex resources utilized by organisms with specialized decay machinery. Wood-decaying fungi represent ideal model systems to study evolution of niche breadth, as they vary greatly in their host range and preferred decay stage of the substrate. In order to dissect the genetic basis for niche specialization in the invasive brown rot fungus Serpula lacrymans, we used phenotyping and integrative analysis of phylogenomic and transcriptomic data to compare this species to wild relatives in the Serpulaceae with a range of specialist to generalist decay strategies. Our results indicate specialist species have rewired regulatory networks active during wood decay towards decreased reliance on enzymatic machinery, and therefore nitrogen-intensive decay components. This shift was likely accompanied with adaptation to a narrow tree line habitat and switch to a pioneer decomposer strategy, both requiring rapid colonization of a nitrogen-limited substrate. Among substrate specialists with narrow niches, we also found evidence for pathways facilitating reversal to generalism, highlighting how evolution may move along different axes of niche space.

Double lives: transfer of fungal endophytes from leaves to woody substrates

Fungal endophytes are a ubiquitous feature of plants, yet for many fungi the benefits of endophytism are still unknown. The Foraging Ascomycete (FA) hypothesis proposes that saprotrophic fungi can utilize leaves both as dispersal vehicles and as resource havens during times of scarcity. The presence of saprotrophs in leaf endophyte communities has been previously observed but their ability to transfer to non-foliar saprobic substrates has not been well investigated. To assess this ability, we conducted a culture study by placing surface-sterilized leaves from a single tropical angiosperm tree (Nectandra lineatifolia) directly onto sterile wood fragments and incubating them for 6 weeks. Fungi from the wood were subsequently isolated in culture and identified to the genus level by ITS sequences or morphology. Four-hundred and seventy-seven fungal isolates comprising 24 taxa were cultured from the wood. Of these, 70.8% of taxa (82.3% of isolates) belong to saprotrophic genera according to the FUNGuild database. Furthermore, 27% of OTUs (6% of isolates) were basidiomycetes, an unusually high proportion compared to typical endophyte communities. Xylaria flabelliformis, although absent in our original isolations, formed anamorphic fruiting structures on the woody substrates. We introduce the term viaphyte (literally, “by way of plant”) to refer to fungi that undergo an interim stage as leaf endophytes and, after leaf senescence, colonize other woody substrates via hyphal growth. Our results support the FA hypothesis and suggest that viaphytism may play a significant role in fungal dispersal.

Hallmarks of basidiomycete soft- and white-rot in wood-decay -omics data of Armillaria

The genus Armillaria spp. (Fungi, Basidiomycota) includes devastating pathogens of temperate forests and saprotrophs that decay wood. Pathogenic and saprotrophic Armillaria species can efficiently colonize and decay woody substrates, however, mechanisms of wood penetration and colonization are poorly known. We assayed the colonization and decay of autoclaved spruce roots using the conifer-specialists Armillaria ostoyae and A. cepistipes using transcriptomic and proteomic data. Transcript and protein levels were altered more extensively in the saprotrophic A. cepistipes than in the pathogenic A. ostoyae and in invasive mycelia of both species compared to their rhizomorphs. Diverse suites of carbohydrate-active enzyme genes (CAZymes), in particular pectinolytic ones and expansins, were upregulated in both species, whereas ligninolytic genes were mostly downregulated. Our gene expression data, together with previous comparative genomic and decay-chemistry analyses suggest that wood decay by Armillaria differs from that of typical white-rot fungi and shows features resembling soft rot. We propose that Armillaria species have modified the ancestral white-rot machinery so that it allows for selective ligninolysis based on environmental conditions and/or host types.

Taxonomy and systematics of Hyaloscyphaceae and Arachnopezizaceae

The circumscription and composition of the Hyaloscyphaceae are controversial and based on poorly sampled or unsupported phylogenies. The generic limits within the hyaloscyphoid fungi are also very poorly understood. To address this issue, a robust five-gene Bayesian phylogeny (LSU, RPB1, RPB2, TEF-1α, mtSSU; 5521 bp) with a focus on the core group of Hyaloscyphaceae and Arachnopezizaceae is presented here, with comparative morphological and histochemical characters. A wide representative sampling of Hyaloscypha supports it as monophyletic and shows H. aureliella (subgenus Eupezizella) to be a strongly supported sister taxon. Reinforced by distinguishing morphological features, Eupezizella is here recognised as a separate genus, comprising E. aureliella, E. britannica, E. roseoguttata and E. nipponica (previously treated in Hyaloscypha). In a sister group to the Hyaloscypha-Eupezizella clade a new genus, Mimicoscypha, is created for three seldom collected and poorly understood species, M. lacrimiformis, M. mimica (nom. nov.) and M. paludosa, previously treated in Phialina, Hyalo­scypha and Eriopezia, respectively. The Arachnopezizaceae is polyphyletic, because Arachnoscypha forms a monophyletic group with Polydesmia pruinosa, distant to Arachnopeziza and Eriopezia; in addition, Arachnopeziza variepilosa represents an early diverging lineage in Hyaloscyphaceae s.str. The hyphae originating from the base of the apothecia in Arachnoscypha are considered anchoring hyphae (vs a subiculum) and Arachnoscypha is excluded from Arachnopezizaceae. A new genus, Resinoscypha, is established to accommodate Arachnopeziza variepilosa and A. monoseptata, originally described in Protounguicularia. Mimicoscypha and Resinoscypha are distinguished among hyaloscyphoid fungi by long tapering multiseptate hairs that are not dextrinoid or glassy, in combination with ectal excipulum cells with deep amyloid nodules. Unique to Resinoscypha is cyanophilous resinous content in the hairs concentrated at the apex and septa. Small intensely amyloid nodules in the hairs are furthermore characteristic for Resinoscypha and Eupezizella. To elucidate species limits and diversity in Arachnopeziza, mainly from Northern Europe, we applied genealogical concordance phylogenetic species recognition (GCPSR) using analyses of individual datasets (ITS, LSU, RPB1, RPB2, TEF-1α) and comparative morphology. Eight species were identified as highly supported and reciprocally monophyletic. Four of these are newly discovered species, with two formally described here, viz. A. estonica and A. ptilidiophila. In addition, Belonium sphagnisedum, which completely lacks prominent hairs, is here combined in Arachnopeziza, widening the concept of the genus. Numerous publicly available sequences named A. aurata represent A. delicatula and the confusion between these two species is clarified. An additional four singletons are considered to be distinct species, because they were genetically divergent from their sisters. A highly supported five-gene phylogeny of Arachnopezizaceae identified four major clades in Arachnopeziza, with Eriopezia as a sister group. Two of the clades include species with a strong connection to bryophytes; the third clade includes species growing on bulky woody substrates and with pigmented exudates on the hairs; and the fourth clade species with hyaline exudates growing on both bryophytes and hardwood. A morphological account is given of the composition of Hyaloscyphaceae and Arachnopezizaceae, including new observations on vital and histochemical characters.

Diatoms in epixylon of waters in the European North (Komi republic, NAO)

The results of studying the diatoms in epixylon of 15 water objects in European Northeast of Russia are presented. The samples of nature biofilms from external surfaces of submersed branches of Betula nana, Salix spp., woody snags, and wood debris were investigated. A comparative analysis of diatoms in fouling of woody substrates was carried out from coal-mine settling pond, lakes, streams, and different parts of mountain river. These are in the basins of Ortina, Vorcuta, More-Yu, Vychegda, Izhgma, Shchugor rivers. In stagnant waters diversity of diatoms form 9–56, in waterways 10–102 taxa. Encyonema minutum (Hilse) Mann, Navicula radiosa Kützing, Tabellaria flocculosa (Roth) Kützing were most frequently. A small degree of diatoms similarity in epixylon with other communities was revealed; the Sørensen coefficient is 0,3–0,4. Part of the diatoms with an abundance 3–6 points (28 taxa) were found only in one water bodies. Among them, in thermokarst lakes with low salinity water and a weakly acid reaction halophobic, acidophilic Eunotia microcephala Krasske, Kobayasiella subtilissima (Cleve) Lange-Bertalot, and Cymbella borealis Cleve prevail. In the coal–mine settling pond dominating group is represented by the alkaliphilic, halophilic Diatoma tenuis C. Agardh, Nitzschia clausii Hantzsch, and Gomphonema productum (Grunow) Lange-Bertot et Reichardt. Mountain streams are distinguished by the development of rheophilic Meridion circulare (Grѐville) C. Agardh, Diatoma mesodon (Ehrenberg) Kützing, Encyonema reichardtii (Krammer) Mann, Fragilaria gracilis Oestrup, Fragilariforma virescens (Ralfs) Williams et Round, Gomphonema montanum (Schumann) Grunow, G. pumilum (Grunow) Reichardt et Lange-Bertalot, G. ventricosum Gregory, Hannaea arcus (Ehrenberg) Patrick var. arcus et f. recta (Cleve) Foged. The composition of the epixylon dominant complexes also differs depending on the hydrological conditions and characteristics of aquatic environment. These differences in this community determine the significant diversity of this group of algae as a whole. In total, 244 species with intraspecific taxa from 67 genera and 27 families identified, and a large number of rare species found.