http://www.economicgeography.org/faculty/dhibbett/Reprints%20PDFs/Wang_et_al_2006_Helotiales.pdf

Evolution of helotialean fungi (Leotiomycetes, Pezizomycotina) : A nuclear rDNA phylogeny

Phylogenetic relationships of one of the largest nonlichen-forming ascomycetous groups, the Leotiomycetes, were inferred from genes encoding three rDNA regions (SSU+LSU+5.8S rDNA). A dataset was prepared with rDNA sequences data from 108 isolates, among which we sampled 85 taxa representing four orders and 16 families in the Leotiomycetes. Equally weighted parsimony and Bayesian analyses were performed. Bootstrap pro- portion and Bayesian posterior probability under the GTR+C+I model were estimated along the branches. Based on our results the Leotiomycetes is relatively well defined as a class and it includes the Cyttariales, Erysiphales, Helotiales, Rhytismatales and two fami- lies of uncertain position, Myxotrichaceae and Pseu- deurotiaceae. The placements of the Thelebolales and Ascocorticiaceae are not examined and are accepted as tentative in the Leotiomycetes. Our results agree with previous studies to remove the Geoglossaceae, including Geoglossum, Trichoglossum and Sarcoleotia, from the Leotiomycetes. Positions of the Erysiphales and Rhytismatales in the Leotiomy- cetes are confirmed. The Helotiales and Myxotricha- ceae are paraphyletic. Close relationships are sup- ported strongly among the Hemiphacidiaceae, Rutstroemiaceae and Sclerotiniaceae, among Lora- mycetaceae, the northern hemisphere Vibrisseaceae, the Dark Septate Endophyte fungus Phialocephala

/pdf/toward-a-phylogenetic-classification-of-the-leotiomycetes-40i9jg4bsa.pdf

Toward a phylogenetic classification of the Leotiomycetes based on rDNA data

Revision of predacious hyphomycetes in the Dactylella-Monacrosporium complex

The literature on teleomorph-anamorph connections in the Orbiliaceae and the position of the family in the Leotiales is reviewed. 18S data show that the Orbiliaceae occupies an isolated position in relationship to the other members of the Leotiales which have so far been studied. The following form genera have been studied in cultures derived from ascospores of Orbiliaceae: Anguillospora, Arthrobotrys, Dactylella, Dicranidion, Helicoon, Monacrosporium, Trinacrium and conidial types that are referred to as being Idriella-like. Characteristics of the anamorphs are discussed and illustrated. Analyses of the ITS region of several of the isolates indicate that there are several well-supported clades within the Orbiliaceae. These clades can be recognized based on the anamorphs produced. They are: an Arthrobotrys-Monacrosporium clade, a Dicranidion clade, and a Helicoon clade. Outside of these clades is a well-supported clade which contains two Arthrobotrys isolates which were derived from conidia produced on natural substrates. The taxonomic and phylogenetic implications of this information are discussed. The Orbiliaceae occur in nature on substrates that are either continually wet or on substrates that periodically dry out. Field observations indicate that those taxa which occur on wet substrates produce perennial mycelia. Some discussion is provided on the way in which scientific information is viewed and can be used.

Castor, pollux and life histories of fungi

Five species of Hymenoscyphus that fruit on black stromatized parts of dead leaves of deciduous trees are presented, giving details on their morphological and ecological characteristics. Several of these species have previously been misplaced in rutstroemiaceous genera because of the presence of a substratal stroma. However, the heteropolar, scutuloid ascospores with an often hook-like lateral protrusion at the rounded apex and the ascus apical ring of the Hymenoscyphus-type represent two reliable morphological characteristics that, together with molecular data, provide clear evidence for their placement in the genus Hymenoscyphus (Helotiaceae). Among the species treated is Hymenoscyphus fraxineus (=Hymenoscyphus pseudoalbidus), the causal agent of the European ash dieback disease. Since 1992 this species started within Europe to replace the rather uncommon Hymenoscyphus albidus, which is likewise confined to leaves of Fraxinus. Hy. fraxineus has been recorded already since 1990 in Eastern Asia (Japan, Korea, northeast of China), where it had been initially misidentified as Lambertella albida (≡Hy. albidus). In these regions, it occurs as a harmless saprotroph on Fraxinus mandshurica and Fraxinus rhynchophylla, suggesting that those populations are native while the European ash dieback disease has a recent Eastern Asiatic origin. The distinctly higher genetic diversity found in Japanese Hy. fraxineus in contrast to European Hy. fraxineus supports this view. Genetic similarities between Japanese Hy. fraxineus and European Hy. albidus suggest that also Hy. albidus might be a descendant of Asian Hy. fraxineus, though having invaded Europe much earlier. However, consistent genetic deviation between European and Asian Hy. fraxineus at two nucleotide positions of the ITS region indicates that the European ash disease originates from a region different from the presently known areas in Eastern Asia. Our results underline the importance of detailed morphological studies in combination with molecular work. Hy. fraxineus was described from Europe as a cryptic species that differed from Hy. albidus by molecular data alone. However, the Hy. albidus/Hy. fraxineus species complex represents one of many examples within the ascomycetes in which subtle microscopic differences between closely related species, in this case the presence or absence of croziers at the ascus base, are strictly correlated with molecular characteristics. Two species that closely resemble Hy. albidus and Hy. fraxineus form pseudosclerotia in Aesculus leaves and again differ from each other mainly in the ascus base: Hymenoscyphus aesculi on Aesculus hippocastanum from Europe lacks croziers, whereas Hymenoscyphus honshuanus from Japan on Aesculus turbinata possesses croziers. Other taxa treated here include Hymenoscyphus vacini, a European species growing on stromatized net veins of skeletonized leaves of Acer, and Hymenoscyphus torquatus, a Chinese species on unidentified herbaceous stems. An equivalent stroma-forming North American species on leaves of Fraxinus, Rutstroemia longipes (Rutstroemiaceae), is discussed and compared. A key to the Hymenoscyphus species that form a dark stroma on leaves of Acer, Aesculus, Fraxinus, and Picrasma is provided.

https://www.tandfonline.com/doi/pdf/10.1080/21501203.2014.963720

Hymenoscyphus fraxineus vs. Hymenoscyphus albidus - A comparative light microscopic study on the causal agent of European ash dieback and related foliicolous, stroma-forming species.

B. M. Spooner

Papers

Helotiales of Australasia: Geoglossaceae, Orbiliaceae, Sclerotiniaceae, Hyaloscyphaceae

Helotiales of Australasia

Helotiales of Australasia: Geoglossaceae, Orbiliaceae, Sclerotiniaceae, Hyaloscyphaceae