Our lab group does research in the area of fungal biology in which we study taxonomy, life histories, and systematics – particularly of fungi in the Pezizomycetes, the Orbiliomycetes and recently in the Laboulbeniomycetes.  We are interested in the relationships among the members of these groups, their geographic distribution, and the associations of these fungi with other organisms.
  • Pfister, D. (Photographer). (2008) Fistulina after harvest  [photograph]. Punta Arenas, Chile.

    Pfister, D. (Photographer). (2008) Fistulina after harvest [photograph]. Punta Arenas, Chile.

  • Haelwaters, D. (Photographer). (2013). Laetiporus sulphureus – Chicken of the woods. [photograph]. Hingham, MA: Worlds End.

    Haelwaters, D. (Photographer). (2013). Laetiporus sulphureus – Chicken of the woods. [photograph]. Hingham, MA: Worlds End.

  • Haelwaters, D. (Photographer). (2013). Trichaptum biforme [photograph]. Hingham, MA: Worlds End.

    Haelwaters, D. (Photographer). (2013). Trichaptum biforme [photograph]. Hingham, MA: Worlds End.

  • Pfister, D. (Photographer). (2008) Peziza, a cup fungus [photograph]. Punta Arenas, Chile.

    Pfister, D. (Photographer). (2008) Peziza, a cup fungus [photograph]. Punta Arenas, Chile.

  • Haelwaters, D. (Photographer). (2013). Gloeoporus-dichrousl [photograph]. Hingham, MA: Worlds End.

    Haelwaters, D. (Photographer). (2013). Gloeoporus-dichrousl [photograph]. Hingham, MA: Worlds End.

  • Haelwaters, D. (Photographer). (2013). Mycena sp. [photograph]. Hingham, MA: Worlds End.

    Haelwaters, D. (Photographer). (2013). Mycena sp. [photograph]. Hingham, MA: Worlds End.

  • Pfister, D. (Photographer). (2008) Cyttaria, a fungal parasite of Nothofagus [photograph]. Punta Arenas, Chile.

    Pfister, D. (Photographer). (2008) Cyttaria, a fungal parasite of Nothofagus [photograph]. Punta Arenas, Chile.

  • Haelwaters, D. (Photographer). (2013). Polyporus alveolaris [photograph]. Hingham, MA: Worlds End.

    Haelwaters, D. (Photographer). (2013). Polyporus alveolaris [photograph]. Hingham, MA: Worlds End.

  • Haelwaters, D. (Photographer). (2013). Schizophyllum commune – Split Gill [photograph]. Hingham, MA: Worlds End.

    Haelwaters, D. (Photographer). (2013). Schizophyllum commune – Split Gill [photograph]. Hingham, MA: Worlds End.

Recent Publications

Phylogeny and taxonomy of the genera of Erysiphaceae, part 5: Erysiphe (the “Microsphaera lineage” part 1)

Bradshaw, M., et al., 2024. Phylogeny and taxonomy of the genera of Erysiphaceae, part 5: Erysiphe (the “Microsphaera lineage” part 1). Mycologia , 116 (1) , pp. 106-147. Publisher's VersionAbstract
In this contribution, we offer the fifth installment of a series focusing on the phylogeny and taxonomy of powdery mildews. This paper is the second segment evaluating the genus Erysiphe. The first treatment of Erysiphe focused on phylogenetically basal species in the “Uncinula lineage.” This research presents a phylogenetic-taxonomic assessment of species that form the group previously referred to as the “Microsphaera lineage.” Given the size of the group, we split the treatment of this lineage of Erysiphe species into two parts based on their phylogenetic placement. Phylogenetic trees based on ITS+28S data are supplemented by sequences of additional markers (CAM, GADPH, GS, RPB2, and TUB). Included in the analysis of the Microsphaera lineage is the “Erysiphe aquilegiae complex” (group, clade, cluster), which encompasses sequences obtained from an assemblage of Erysiphe species with insufficient resolution in rDNA analyses. Attempts have been made to resolve this group at the species level by applying a multilocus approach. A detailed discussion of the “Erysiphe aquilegiae complex” is provided. Sequences are provided for the first time for several species, particularly North American species, such as Erysiphe aggregata, E. erineophila, E. parnassiae, and E. semitosta. Ex-type sequences for Microsphaera benzoin and M. magnusii have been retrieved. Alphitomorpha penicillata, Microsphaera vanbruntiana, and M. symphoricarpi are epitypified with ex-epitype sequences. The new species Erysiphe alnicola, E. deutziana, E. cornigena, E. lentaginis, and E. sambucina are described, the new combinations E. lauracearum, E. passiflorae, and E. sambucicola are introduced, and the new name E. santali is proposed.
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Cytological studies reveal high variation in ascospore number and shape and conidia produced directly from ascospores in Morchella galilaea.

Du, X.H., et al., 2023. Cytological studies reveal high variation in ascospore number and shape and conidia produced directly from ascospores in Morchella galilaea. Frontiers in Microbiology. Publisher's VersionAbstract
Spores are important as dispersal and survival propagules in fungi. In this study we investigated the variation in number, shape, size and germination mode of ascospores in Morchella galilaea, the only species of the genus Morchella known to fruit in the autumn. Based on the observation of five samples, we first discovered significant variation in the shape and size of ascospores in Morchella. One to sixteen ascospores were found in the asci. Ascospore size correlated negatively with ascospore number, but positively with ascus size, and ascus size was positively correlated with ascospore number. We noted that ascospores, both from fresh collections and dried specimens, germinated terminally or laterally either by extended germ tubes, or via the production of conidia that were formed directly from ascospores at one, two or multiple sites. The direct formation of conidia from ascospores takes place within asci or after ascospores are discharged. Using laser confocal microscopy, we recorded the number of nuclei in ascospores and in conidia produced from ascospores. In most ascospores of M. galilaea, several nuclei were observed, as is typical of species of Morchella. However, nuclear number varied from zero to around 20 in this species, and larger ascospores harbored more nuclei. One to six nuclei were present in the conidia. Nuclear migration from ascospores to conidia was observed. Conidia forming directly from ascospores has been observed in few species of Pezizomycetes; this is the first report of the phenomenon in Morchella species. Morphological and molecular data show that conidial formation from ascospores is not found in all the specimens of this species and, hence, is not an informative taxonomic character in M. galilaea. Our data suggest that conidia produced from ascospores and successive mitosis within the ascus may contribute to asci with more than eight spores. The absence of mitosis and/or nuclear degeneration, as well as cytokinesis defect, likely results in asci with fewer than eight ascospores. This study provides new insights into the poorly understood life cycle of Morchella species and more broadly improves knowledge of conidia formation and reproductive strategies in Pezizomycetes.
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The Erysiphe alphitoides complex (powdery mildews) – unravelling the phylogeny and taxonomy of an intricate assemblage of species

Bradshaw, M., et al., 2023. The Erysiphe alphitoides complex (powdery mildews) – unravelling the phylogeny and taxonomy of an intricate assemblage of species. New Zealand Journal of Botany . Publisher's VersionAbstract

Powdery mildews on oaks, caused by Erysiphe species, have serious ecological consequences on a range of Quercus hosts. In addition to Erysiphe quercicolaE. alphitoides is one of the most common and widespread species of Erysiphe having a wide host range among oak species, and a clear economic significance in applied ecology, forestry, and forest pathology. There are many publications addressing these important tree pathogens. Previous phylogenetic examinations have shown that E. alphitoides refers to a complicated species assemblage with insufficient taxonomic resolution in ITS + 28S analyses; the associated sequences form an insufficiently resolved species complex. The majority of species within the E. alphitoides complex cannot be unequivocally identified based solely on ITS + 28S analyses. Most of the additional species of the E. alphitoides complex are distributed in Asia, with a concentration in Japan. The question posed is whether there is a single widespread powdery mildew species, E. alphitoides, or an assemblage of closely allied species. To answer this question, specimens of related recognized species, particularly those from Japan, have been subjected to phylogenetic multilocus examinations, including CAMGAPDHGS, ITS + 28S, RPB2, and TUB sequences. An analysis of the concatenated sequences resulted in the confirmation of several distinct species. These species form highly supported clades that include E. alphitoidesE. aucubaeE. euonymicolaE. ipomoeaeE. menispermi var. dahuricaE. orixaeE. pseudoloniceraeE. sinomenii and E. wallrothiiErysiphe akebiae as well as the relationship between Japanese and North American collections requires further examinations.

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Phylogeny and taxonomy of the genera of Erysiphaceae, part 4: Erysiphe (the “Uncinula lineage”)

Bradshaw, M., Braun, U. & Pfister, D.H., 2023. Phylogeny and taxonomy of the genera of Erysiphaceae, part 4: Erysiphe (the “Uncinula lineage”). Mycologia. Publisher's VersionAbstract
This is the fourth contribution within an ongoing series dedicated to the phylogeny and taxonomy of powdery mildews. This particular installment undertakes a comprehensive evaluation of a group previously referred to as the “Uncinula lineage” within Erysiphe. The genus Erysiphe is too large to be assessed in a single paper; thus, the treatment of Erysiphe is split into three parts, according to phylogenetic lineages. The first paper, presented here, discusses the most basal lineage of Erysiphe and its relationship to allied basal genera within tribe Erysipheae (i.e., Brasiliomyces and Salmonomyces). ITS+28S analyses are insufficient to resolve the basal assemblage of taxa within the Erysipheae. Therefore, phylogenetic multilocus examinations have been carried out to better understand the evolution of these taxa. The results of our analyses favor maintaining Brasiliomyces, Bulbomicroidium, and Salmonomyces as separate genera, at least for the interim, until further phylogenetic multilocus data are available for additional basal taxa within the Erysipheae. The current analyses also confirmed previous results that showed that the “Uncinula lineage” is not exclusively composed of Erysiphe species of sect. Uncinula but also includes some species that morphologically align with sect. Erysiphe, as well as species that had previously been assigned to Californiomyces and Typhulochaeta. Numerous sequences of Erysiphe species from the “Uncinula lineage” have been included in the present phylogenetic analyses and were confirmed by their position in well-supported species clades. Several species have been sequenced for the first time, including Erysiphe clintonii, E. couchii, E. geniculata, E. macrospora, and E. parvula. Ex-type sequences are provided for 16 taxa including E. nothofagi, E. trinae, and E. variabilis. Epitypes are designated and ex-epitype sequences are added for 18 taxa including Erysiphe carpophila, E. densa, and U. geniculata var. carpinicola. The new species Erysiphe canariensis is described, and the new names E. hosagoudarii and E. pseudoprunastri and the new combination E. ampelopsidis are introduced.
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