Divergence time calibrations for ancient lineages of Ascomycota classification based on a modern review of estimations

A new fossil species of Meliolinites Selkirk associated with Rhodoleia leaves from the Upper Pliocene of southwestern China

Fossil epifoliar fungi are valuable indicators of paleoenvironment and paleoecology. The Meliolaceae, members of which typically inhabit the surface of living plants as biotrophs or pathogens, is one of the largest groups of epifoliar fungi. In this study, we report a novel fossil species of Meliolinites Selkirk (fossil Meliolaceae), Meliolinites tengchongensis, on the lower epidermis of compressed fossil Rhodoleia (Hamamelidaceae) leaves from the Upper Pliocene Mangbang Formation of Tengchong, Yunnan, southwestern China. Meliolinites tengchongensis is characterized by web-like, superficial, brown to dark brown, septate, and branching mycelia bearing 2-celled appressoria and unicellular phialides. The fungal colonies also include ellipsoidal, 5-celled, 4-septate ascospores and dark brown perithecia with suborbicular outline and verrucose surface. The well-preserved vegetative and reproductive organs help us to explore the potential disease process of the new fossil species. Besides, the presence of fungal remains indicates that the fungal taxon might have maintained its host preference since at least the Late Pliocene. Furthermore, the occurrence of both fossil fungi and their host plants in Tengchong indicate a subtropical-tropical, warm, and humid climate during the Late Pliocene, whereas the distribution pattern of the fungi on the host leaves suggests that Rhodoleia may have been a part of the middle-upper canopies in the Tengchong Late Pliocene multilayered forest.

Taxonomy and evolution history of two new litter-decomposing Ciliochorella (Amphisphaeriales, Sporocadaceae)

The genus Ciliochorella is a group of pestalotioid fungi, which typically occurs in subtropical and tropical areas. Species from the Ciliochorella genus play important roles in the decomposition of litter. In this study, we introduce two new species (Ciliochorellachinensissp. nov. and C.savannicasp. nov.) that were found on leaf litter collected from savanna-like vegetation in hot dry valleys of southwestern China. Phylogenetic analyses of combined LSU, ITS and tub2 sequence datasets indicated that C.chinensis and C.savannica respectively form a distinct clade within the Ciliochorella genus. The comparison of the morphological characteristics indicated that the two new species are well differentiated within this genus species. Analysis of the evolutionary history suggests that Ciliochorella originated from the Eurasian continent during the Paleogene (38 Mya). Further, we find that both new species can produce cellulase and laccase, playing a decomposer role.

Grazing practices affect soil microbial networks but not diversity and composition in alpine meadows of northeastern Qinghai-Tibetan plateau

Livestock grazing is the primary practice in alpine meadows and can alter soil microbiomes, which is critical for ecosystem functions and services. Seasonal grazing (SG) and continuous grazing (CG) are two kinds of different grazing practices that dominate alpine meadows on the Qinghai-Tibetan Plateau (QTP), and how they affect soil microbial communities remains in-depth exploration. The present study was conducted to investigate the effects of different grazing practices (i.e., SG and CG) on the diversity, composition, and co-occurrence networks of soil bacteria and fungi in QTP alpine meadows. Soil microbial α- and β-diversity showed no obvious difference between SG and CG grasslands. Grazing practices had little impact on soil microbial composition, except that the relative abundance of Proteobacteria and Ascomycota showed significant difference between SG and CG grasslands. Soil microbial networks were more complex and less stable in SG grasslands than that in CG grasslands, and the bacterial networks were more complex than fungal networks. Soil fungal diversity was more strongly correlated with environmental factors than bacteria, whereas both fungal and bacterial structures were mainly influenced by soil pH, total nitrogen, and ammonium nitrogen. These findings indicate that microbial associations are more sensitive to grazing practices than microbial diversity and composition, and that SG may be a better grazing practice for ecological benefits in alpine meadows.

Fossil history of fungus host-specificity: Association of conidia of fossil Asterosporium asterospermum with macro- and microremains of Fagus

Fossil staurosporous conidia almost identical to modern conidia of Asterosporium asterospermum were found from three Central European localities ranging from the Late Oligocene (Germany) to Middle/Late Miocene (Poland). Extant A. asterospermum is strictly host-specific and found only on branches or bark of various Fagus species from Europe, Asia and North America. Conspicuous association of conidia of A. asterospermum with numerous macro- and microremains of Fagus were reported from all the localities where fossil conidia of Asterosporium were found confirming the host-specificity of fossil A. asterospermum to ancient beeches. The host-specific relationship of A. asterospermum and beech was presumably established early in the history of the Fagus genus.

The first fossil record of the anamorphic genus Zygosporium Mont. from the Oligocene of Csolnok (N Hungary)

Remains of a fungus with unique morphological characters were found on the leaf cuticle of a fossil leaf preserved in Oligocene deposits from Csolnok, Hungary. Vesicular conidiophores with characteristic, darkly pigmented, incurved vesicles were compared with those of the modern representatives of the anamorphic genus Zygosporium. Based on the fossil find, a new fossil-species, Zygosporium oligocenicum G. Worobiec sp. nov., having vesicular conidiophores that arise directly from the mycelium, was described. The fossil Zygosporium oligocenicum presumably preferred warm climate and, similarly to most modern members of the genus, was a saprophyte on fallen, decaying leaves.

New species and records of Neomassaria, Oxydothis and Roussoella (Pezizomycotina, Ascomycota) associated with palm and bamboo from China

Several micro fungi were gathered from bamboo and palm in Guizhou Province, China. In morphology, these taxa resemble Neomassaria, Roussoella and Oxydothis. Multi-gene phylogenetic analyses based on combined ITS, LSU, SSU, rpb2 and tef1 loci confirmed that two are new geographical records for China, (viz. Roussoellasiamensis, Neomassariafabacearum), while two of them are new to science (viz. Oxydothisfortunei sp. nov. and Roussoellabambusarum sp. nov.). The stromata of Roussoellabambusarum are similar to those of R.thailandica, but its ascospores are larger. In addition, multi-gene phylogenetic analyses show that Oxydothisfortunei is closely related to O.inaequalis, but the J- ascus subapical ring as well as the ascospores of O.inaequalis are smaller. Morphological descriptions and illustrations of all species are provided.

Phylogenetic and ecological reevaluation of the order Onygenales

The order Onygenales is classified in the class Eurotiomycetes of the subphylum Pezizomycotina. Families in this order have classically been isolated from soil and dung, and two lineages contain causative agents of superficial, cutaneous and systemic infections in mammals. The ecology and habitat choices of the species are driven mainly by the keratin and cellulose degradation abilities. The present study aimed to investigate whether the ecological trends of the members of Onygenales can be interpreted in an evolutionary sense, linking phylogenetic parameters with habitat preferences, to achieve polyphasic definitions of the main taxonomic groups. Evolutionary processes were estimated by multiple gene genealogies and divergence time analysis. Previously described families, namely, Arthrodermataceae, Ajellomycetaceae, Ascosphaeraceae, Eremascaceae, Gymnoascaceae, Onygenaceae and Spiromastigoidaceae, were accepted in Onygenales, and two new families, Malbrancheaceae and Neogymnomycetaceae, were introduced. A number of species could not be assigned to any of the defined families. Our study provides a revised overview of the main lines of taxonomy of Onygenales, supported by multilocus analyses of ITS, LSU, TUB, TEF1, TEF3, RPB1, RPB2, and ribosomal protein 60S L10 (L1) (RP60S) sequences, combined with available data on ecology, physiology, morphology, and genomics.

Sooty molds from the Jurassic of Patagonia, Argentina

PREMISE

The sooty molds are a globally distributed ecological group of ascomycetes with epiphyllous, saprotrophic habit, comprising several phylogenetically distant taxa (i.e., members of the classes Dothideomycetes and Eurotiomycetes). Their fossil record extends almost continuously back to the early Cretaceous; however, they are hypothesized to have originated in the early Mesozoic. Here, we describe new specimens of sooty molds associated with conifer leaves from Jurassic hot spring deposits of Patagonia, Argentina.

METHODS

Thin sections of chert samples from the La Matilde Formation, Deseado Massif (Santa Cruz, Argentina) were observed using light microscopy.

RESULTS

The fungi occur on the surface and axils of leafy twigs with podocarpaceous affinities, forming dense subicula comprised by opaque moniliform hyphae. Additionally, several asexual and sexual reproductive structures are observed. On the basis of vegetative (i.e., dense subicula composed of moniliform hyphae; hyphae composed of opaque cells deeply constricted at the septa) and reproductive characters (i.e., poroconidial and sympodioconidial asexual stages and diverse spores), two morphotypes were identified with affinities within lineages of the subphylum Pezizomycotina that encompass the ecological group of sooty molds, and a third morphotype was within the phylum Ascomycota.

CONCLUSIONS

This finding extends the fossil record of sooty molds to the Jurassic and their geographic fossil range to the South American continent. In particular, their association with podocarpaceous conifers is shown to be ancient, dating back to the Jurassic. This new record provides an additional reference point on the diversity of interactions that characterized Jurassic forests in Patagonia.

Sareomycetes: more diverse than meets the eye

Since its resurrection, the resinicolous discomycete genus Sarea has been accepted as containing two species, one with black apothecia and pycnidia, and one with orange. We investigate this hypothesis using three ribosomal (nuITS, nuLSU, mtSSU) regions from and morphological examination of 70 specimens collected primarily in Europe and North America. The results of our analyses support separation of the traditional Sarea difformis s.lat. and Sarea resinae s.lat. into two distinct genera, Sarea and Zythia. Sarea as circumscribed is shown to conservatively comprise three phylospecies, with one corresponding to Sarea difformis s.str. and two, morphologically indistinguishable, corresponding to the newly combined Sarea coeloplata. Zythia is provisionally maintained as monotypic, containing only a genetically and morphologically variable Z. resinae. The new genus Atrozythia is erected for the new species A. klamathica. Arthrographis lignicola is placed in this genus on molecular grounds, expanding the concept of Sareomycetes by inclusion of a previously unknown type of asexual morph. Dating analyses using additional marker regions indicate the emergence of the Sareomycetes was roughly concurrent with the diversification of the genus Pinus, suggesting that this group of fungi emerged to exploit the newly-available resinous ecological niche supplied by Pinus or another, extinct group of conifers. Our phylogeographic studies also permitted us to study the introductions of these fungi to areas where they are not native, including Antarctica, Cape Verde, and New Zealand and are consistent with historical hypotheses of introduction.

Integrating Different Lines of Evidence to Establish a Novel Ascomycete Genus and Family (Anastomitrabeculia, Anastomitrabeculiaceae) in Pleosporales

A novel genus, Anastomitrabeculia, is introduced herein for a distinct species, Anastomitrabeculia didymospora, collected as a saprobe on dead bamboo culms from a freshwater stream in Thailand. Anastomitrabeculia is distinct in its trabeculate pseudoparaphyses and ascospores with longitudinally striate wall ornamentation. A new family, Anastomitrabeculiaceae, is introduced to accommodate Anastomitrabeculia. Anastomitrabeculiaceae forms an independent lineage basal to Halojulellaceae in Pleosporales and it is closely related to Neohendersoniaceae based on phylogenetic analyses of a combined LSU, SSU and TEF1α dataset. In addition, divergence time estimates provide further support for the establishment of Anastomitrabeculiaceae. The family diverged around 84 million years ago (MYA) during the Cretaceous period, which supports the establishment of the new family. The crown and stem age of Anastomitrabeculiaceae was also compared to morphologically similar pleosporalean families.

Genome-scale phylogeny and contrasting modes of genome evolution in the fungal phylum Ascomycota

Ascomycota, the largest and most well-studied phylum of fungi, contains three subphyla: Saccharomycotina (budding yeasts), Pezizomycotina (filamentous fungi), and Taphrinomycotina (fission yeasts). Despite its importance, we lack a comprehensive genome-scale phylogeny or understanding of the similarities and differences in the mode of genome evolution within this phylum. By examining 1107 genomes from Saccharomycotina (332), Pezizomycotina (761), and Taphrinomycotina (14) species, we inferred a robust genome-wide phylogeny that resolves several contentious relationships and estimated that the Ascomycota last common ancestor likely originated in the Ediacaran period. Comparisons of genomic properties revealed that Saccharomycotina and Pezizomycotina differ greatly in their genome properties and enabled inference of the direction of evolutionary change. The Saccharomycotina typically have smaller genomes, lower guanine-cytosine contents, lower numbers of genes, and higher rates of molecular sequence evolution compared with Pezizomycotina. These results provide a robust evolutionary framework for understanding the diversity and ecological lifestyles of the largest fungal phylum.

Fossil callimothalloid fungi: Revised taxonomy, modern equivalents and palaeoecology

This paper presents the reinterpretation of the taxonomic position of fossil epiphyllous callimothalloid fungi belonging to the fossil-genera Callimothallus (hitherto classified to the family Microthyriaceae) and Cribrites (?Microthyriales). These fungi thrived from the Late Cretaceous up to the Holocene. Investigation are based on collected material from the Oligocene of Hungary and the Miocene of Poland and on published data. For the common callimothalloid fungus Callimothallus pertusus, a new combination Neomycoleptodiscus pertusus is proposed. Callimothallus quilonensis is assigned to a new fossil-genus Muyocopromyces as a new combination Muyocopromyces quilonensis. We reconsider the fossil-species Ratnagiriathyrites hexagonalis as a younger synonym of the fossil-genus Cribrites. The geographical range of fossil callimothalloid fungi and their recent counterparts are discussed. Fossil Neomycoleptodiscus, Muyocopromyces, and Cribrites are proposed as reliable climate proxy of warm climate conditions in the past.

Lichenopeltella mizerniana sp. nov. from the upper Pliocene of Mizerna (southern Poland)

Fungal sporocarps having ostiole with setae were found in the upper Pliocene deposits from Mizerna (borehole Mizerna-Nowa), southern Poland. These remains morphologically correspond to the fossil-genus Trichothyrites Rosend., although the structure of the ostiolar collar with non-septate setae seems unique and is typical for sporocarps (catathecia) of some modern species of the genus Lichenopeltella Höhn. Other contemporary fungal genera with setose sporocarps differ considerably from Lichenopeltella in respect of their morphology. Taking this into consideration, a new fossil-species Lichenopeltella mizerniana G. Worobiec is proposed. Morphologically, Lichenopeltella mizerniana is similar both to some modern lichenicolous [L. peltigericola (D. Hawksw.) R. Sant., L. rangiferinae Brackel, and L. uncialicola Brackel] and non-lichenicolous species [L. ammophilae (J.P. Ellis) P.M. Kirk & Minter, L. palustris (J.P. Ellis) P.M. Kirk & Minter] of this genus. The presence of Lichenopeltella mizerniana suggests that the Pliocene climate of the Mizerna locality was probably at least moderately humid.

A re-evaluation of the Chaetothyriales using criteria of comparative biology

Chaetothyriales is an ascomycetous order within Eurotiomycetes. The order is particularly known through the black yeasts and filamentous relatives that cause opportunistic infections in humans. All species in the order are consistently melanized. Ecology and habitats of species are highly diverse, and often rather extreme in terms of exposition and toxicity. Families are defined on the basis of evolutionary history, which is reconstructed by time of divergence and concepts of comparative biology using stochastical character mapping and a multi-rate Brownian motion model to reconstruct ecological ancestral character states. Ancestry is hypothesized to be with a rock-inhabiting life style. Ecological disparity increased significantly in late Jurassic, probably due to expansion of cytochromes followed by colonization of vacant ecospaces. Dramatic diversification took place subsequently, but at a low level of innovation resulting in strong niche conservatism for extant taxa. Families are ecologically different in degrees of specialization. One of the clades has adapted ant domatia, which are rich in hydrocarbons. In derived families, similar processes have enabled survival in domesticated environments rich in creosote and toxic hydrocarbons, and this ability might also explain the pronounced infectious ability of vertebrate hosts observed in these families. Conventional systems of morphological classification poorly correspond with recent phylogenetic data. Species are hypothesized to have low competitive ability against neighboring microbes, which interferes with their laboratory isolation on routine media. The dataset is unbalanced in that a large part of the extant biodiversity has not been analyzed by molecular methods, novel taxonomic entities being introduced at a regular pace. Our study comprises all available species sequenced to date for LSU and ITS, and a nomenclatural overview is provided. A limited number of species could not be assigned to any extant family.