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.
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.
Ascospore morphologies provide important characters with which to diagnose and describe taxa in Ascomycota. Ascospore features such as size, shape, color, septation, wall thickness, and guttulation, among others, are provided in identification manuals and descriptions of new species. Yet, by tradition, ascospores are usually described from dead fungarium material, and unfortunately, occasionally from immature or overmature ones. However, living, mature ascospores display a wealth of taxonomically informative morphological features that are lost or obscured when they die. Examples of the severe morphological changes that ascospores undergo when they die are provided here. Data from living ascospores may not be observed and recorded by mycologists because field and laboratory practices do not prioritize the study of freshly collected specimens. In this review, we discuss how to assess ascospore maturity and describe methods to produce an ascospore deposit for the purpose of obtaining living, mature ascospores. Ascospores are ejected from living, mature asci onto a cover glass or growth medium. The ascospores collected on these surfaces can be used in microscopy and culture studies. Notes on a method for isolating conidia on growth medium are also provided. This guide is aimed at those who have a basic understanding of ascomycetes, including the various types of ascomata and mechanisms of ascospore liberation. Methods given in this paper are primarily applied to ascomycete fungi that have active ascospore discharge. Some methods may be adapted for use with other groups that have passive discharge. Our purpose is to promote standardized, accurate, and thorough morphological characterization of living ascospores, as well as to encourage the routine employment of culture-based methods.
Introduction The Pezizomycetes comprise a single order, Pezizales, with > 22 families currently recognized. Along with the Orbiliomycetes, the class represents one of the basal lineages among the filamentous Ascomycota (Shen et al., 2020). The class is thought to have originated between 400 and 540 mya (Beimforde et al., 2014; Martin et al., 2010; Murat et al., 2018). The full diversity of the order has yet to be completely documented since previously undetected lineages continue to be found through application of molecular methods. There are approximately 200 genera and perhaps 2000 species. Ascomata are epigeous (above ground), or hypogeous (below ground). The truffles of commerce belong to this latter group. The epigeous ascomata are apotl1ecial, deistothecial or are highly reduced. The reduced forms are composed of only a few asci in dusters on vegetative hyphae with little or no sterile supporting tissue ( excipulum). In the ep,lppigeous lineages, ascospores are generally forcibly released by an opening at the ascus apex resulting in the formation of an operculum, or lid. Hypogeous members occur in several of the families. There are at least 30 independent origins of truffle-like members (Alvarado et al., 2011, 2016; Cabera et al., 2016; Grupe et al., 2019; llansen et al., 2013; Kraisitudomsook et al., 2019; Kumar et al., 2017; Laessoe and Hansen, 2007; Smith, 2014; Smith and Healy, 2009; Trappe et al., 2010)
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.l. and Sarea resinae s.l. into two distinct genera, Sarea and Zythia. Sarea as circumscribed is shown to comprise three phylospecies, with one corresponding to Sarea difformis s.s. and two, morphologically indistinguishable, corresponding to the newly combined Sarea coeloplata. Zythia is 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 anamorph. 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.
Ascomata of Trichaleurina javanica (Pezizomycetes) are encountered frequently in nature in tropical Asia. Its anamorphic state has been described previously as similar to Kumanasamuha. Our study describes the unusual anamorphic fungal specimen, MOZ170, collected from Gorongosa National Park, Mozambique. The fungal strain MOZ170 is identified using ribosomal DNA sequence data, its morphology is described, and morphological differences between the naturally growing anamorph and in vitro derived culture are compared. Phylogenetic placement of Kumanasamuha sundara was also determined using available data. The internal transcribed spacer (ITS) and partial large ribosomal subunit (LSU) were sequenced. Phylogenetic analyses of LSU supported MOZ170 as the anamorph of T. javanica, and revealed the proper placement of the type species of Kumanasamuha, i.e., K. sundara, within the Dothideomycetes. MOZ170 is characterized by its dark conidiophores growing in tufts, and conidia with curved, appressed crests and ridges. The comparison between naturally growing and in vitro grown cultures showed that the in vitro cultured anamorph had larger conidiogenous cells, larger conidia, and longer and more numerous lateral fertile branches compared to the fungus in nature. The present report represents the first anamorph collected from nature for this genus and one of the few natural collections of the anamorphic state within Chorioactidaceae with the exception of those of Desmazierella species.