From Lamarckian fertilizers to fungal castles: recapturing the pre-1985 literature on endophytic and saprotrophic fungi associated with ectomycorrhizal root systems

AbstractThe endophytic, mantle-inhabiting and rhizosphere-inhabiting microorganisms associated with ectomycorrhizal roots have been studied for over 100 years, but a surprising amount of the information obtained prior to the mid-1980's is difficult to access and understand. In large part, this is because research investigating local ecosystems and silvicultural practices was often considered regional in nature. It tended to be written up in many different languages and to be published in journals that were not widely distributed. After 1985, this scientific isolationism was broken up by the ubiquitous trend towards impact factor measurement and international publishing. The goal of the present review is to make still-relevant information from the pre-1985 ectomycorrhizosphere literature, especially its more strongly obscured elements, readily accessible to modern researchers. Also, some publications that fell into relative obscurity for historical reasons – in particular, studies seeming to reflect the brief association of Soviet mycorrhizal research of the early 1950's with the Lamarckian plant improvement ideas of T. D. Lysenko – are re-examined from current perspectives. The scattered data reveal considerable coherence despite the high ecological diversity they reflect. Endophytes such as members of the Mycelium radicis atrovirens complex – most prominently the species now known as Phialocephala fortinii – feature especially prominently in this area of study, and they received considerable attention beginning in the very early years of the 20th century. They were variously interpreted as potential symbionts or weak pathogens, an ambiguity that continues to the present day for many of these taxa despite the recent molecular clarification of species and population boundaries. The predominance of P. fortinii and other (normally) non-mycorrhizal “dark (or hyaline) sterile endophyte” fungi from stringently washed or surface-disinfected ectomycorrhizae in most ecosystems was shown repeatedly beginning with the studies of Elias Melin in the early 1920's. The adjacent rhizosphere soil typically contained sporulating fungi dominated by Penicillium, Umbelopsis and Mortierella species, sometimes accompanied by Trichoderma spp., Cylindrocarpon destructans, and various other microfungi. Microbiological investigations into whether ectomycorrhizae exerted a positive “rhizosphere effect” on numbers of fungal propagules in the surrounding soil showed that such effects were often less prominent in natural forests than in planted forests. Several studies showed a general reduction in microbial activity in the zone of ectomycorrhizal influence, and a particularly strong inhibition of soil organisms was shown in the symbiorhizosphere of Tricholoma matsutake and members of the genus Tuber. In relation to such cases, the adoption by mycologists of M. Ogawa's term “shiro”, (castle, fortress) for the delimited, three-dimensional analogue of a fairy ring formed in soil by many ectomycorrhizal mycobionts is advocated. As relatively highly co-adapted communities, ectomycorrhizosphere organisms appeared to aid in root disease control, in part by harmlessly stimulating roots to produce defensive tannic materials. The production of these materials then appeared to favour the predominance of tannin-degrading Penicillium species in the rhizosphere. Rhizosphere inhabitants were shown to be involved in many types of nutrient and growth factor exchanges, but perhaps to be most important as solubilizers of refractory nutrients like inorganic phosphorus compounds and complex proteinaceous materials. Some potential pathogens like Fusarium spp. tended to be excluded from established forest soils, while Cylindrocarpon destructans, if present, tended to be confined to lower soil regions by microbial acidification of the upper soil zones. The complexity of microfungal communities and their known and potential interactions was high, and seemingly contradictory results often needed to be rationalized, e.g., Trichoderma spp. appeared to be favoured in the root zone in some ecosystems and partially excluded in others, and seemed to abet mycorrhiza formation and tree growth in some habitats but to cause damage to seedlings and mycorrhizal inoculum both in vitro and in the nursery. Modern techniques and bioinformatics methodologies will be needed to make progress towards understanding this complexity, but the multilingual and sometimes overlooked pre-1985 studies provide a very strong initial basis supporting further development

Detection of Xanthomegnin in Epidermal Materials Infected with Trichophyton rubrum

Xanthomegnin, a mutagenic mycotoxin best known as an agent of nephropathy and death in farm animals exposed to food-borne Penicillium and Aspergillus fungi, was first isolated about 35 y ago as a diffusing pigment from cultures of the dermatophyte, Trichophyton megninii. This study investigates the production of xanthomegnin by the most common dermatophytic species, Trichophyton rubrum, both in dermatologic nail specimens and in culture. In view of the labile nature of xanthomegnin, a chromatographic procedure was developed to allow high-performance liquid chromatography analysis within 1 h of sample extraction. In cultures, Tricho- phyton rubrum produced xanthomegnin as a major pigment that appears to give the culture its characteristic red colony reverse. Xanthomegnin was also repeatedly extracted from human nail and skin material infected by Trichophyton rubrum. The level of xanthomegnin present, however, varied among the clinical samples studied. Xanthomegnin was not detected in uninfected nails. These results show that patients with Trichophyton rubrum infections may be exposed to xanthomegnin, although the consequences of such an exposure are not currently known

Antigenic relations between pathogenic Paecilomyces lilacinus and P. variotii and other hyalohyphomycotic agents

AbstractObjective: The antigenic relations between Paecilomyces variotii and Paecilomyces lilacinus were studied by comparison of their exoantigens.Methods: Forty-one isolates of hyalohyphomycosis-causing fungi including P. lilacinus (n = 15) and P. variotii (n = 12), one isolate each of Paecilomyces inflatus, Paecilomyces marquandii, and Paecilomyces carneus, Fusarium species (n = 3), Neosartorya pseudofischeri (n = 5), and Penicillium species (n = 3), were studied using the exo-antigen test. Ten-day-old extracts derived from Sabouraud's dextrose agar slants were concentrated (25x), and reacted against rabbit anti-P. lilacinus and anti-P. variotii sera in the presence of partially purified homologous antigens (20x) prepared from 5-week-old shaken cultures. Extracts of isolates of P. lilacinus and P. variotii produced one to three lines of identity against the reference homologous antisera. No cross-reactivity or bands of non-identity were observed with other Paecilomyces isolates, N. pseudofischeri, Fusarium species, and Penicillium species isolates.Conclusion: The results of this investigation indicate that P. lilacinus and P. variotii are antigenically distinct and that they can be identified rapidly and accurately by their exoantigens. Exoantigen extracts of morphologically similar fungi and other species of Paecilomyces isolates studied did not possess antigens common to P. lilacinus and P. variotii

Taxonomy and pathology of Togninia (Diaporthales) and its Phaeoacremonium anamorphs.

The genus Togninia (Diaporthales, Togniniaceae) is here monographed along with its Phaeoacremonium (Pm.) anamorphs. Ten species of Togninia and 22 species of Phaeoacremonium are treated. Several new species of Togninia (T.) are described, namely T. argentinensis (anamorph Pm. argentinense), T. austroafricana (anamorph Pm. austroafricanum), T. krajdenii, T. parasitica, T. rubrigena and T. viticola. New species of Phaeoacremonium include Pm. novae-zealandiae (teleomorph T. novae-zealandiae), Pm. iranianum, Pm. sphinctrophorum and Pm. theobromatis. Species can be identified based on their cultural and morphological characters, supported by DNA data derived from partial sequences of the actin and ß-tubulin genes. Phylogenies of the SSU and LSU rRNA genes were used to determine whether Togninia has more affinity with the Calosphaeriales or the Diaporthales. The results confirmed that Togninia had a higher affinity to the Diaporthales than the Calosphaeriales. Examination of type specimens revealed that T. cornicola, T. vasculosa, T. rhododendri, T. minima var. timidula and T. villosa, were not members of Togninia. The new combinations Calosphaeria cornicola, Calosphaeria rhododendri, Calosphaeria transversa, Calosphaeria tumidula, Calosphaeria vasculosa and Jattaea villosa are proposed. Species of Phaeoacremonium are known vascular plant pathogens causing wilting and dieback of woody plants. The most prominent diseases in which they are involved are Petri disease and esca, which occur on grapevines and are caused by a complex of fungi, often including multiple species of Phaeoacremonium. Various Phaeoacremonium species are opportunistic fungi on humans and cause phaeohyphomycosis. The correct and rapid identification of Phaeoacremonium species is important to facilitate the understanding of their involvement in plant as well as human disease. A rapid identification method was developed for the 22 species of Phaeacremonium. It involved the use of 23 species-specific primers, including 20 primers targeting the ß-tubulin gene and three targeting the actin gene. These primers can be used in 14 multiplex reactions. Additionally, a multiple-entry electronic key based on morphological, cultural and ß-tubulin sequence data was developed to facilitate phenotypic and sequence-based species identification of the different Phaeoacremonium species. Separate dichotomous keys are provided for the identification of the Togninia and Phaeoacremonium species. Keys for the identification of Phaeoacremonium-like fungi and the genera related to Togninia are also provided. The mating strategy of several Togninia species was investigated with ascospores obtained from fertile perithecia produced in vitro. Togninia argentinensis and T. novae-zealandiae have homothallic mating systems, whereas T. austroafricana, T. krajdenii, T. minima, T. parasitica, T. rubrigena and T. viticola were heterothallic.

Blastomycosis in Ontario, 1994–2003

Clinicians in Ontario should be aware of symptoms and areas where disease is endemic

Fusarium and allied fusarioid taxa (FUSA). 1

Seven Fusarium species complexes are treated, namely F. aywerte species complex (FASC) (two species), F. buharicum species complex (FBSC) (five species), F. burgessii species complex (FBURSC) (three species), F. camptoceras species complex (FCAMSC) (three species), F. chlamydosporum species complex (FCSC) (eight species), F. citricola species complex (FCCSC) (five species) and the F. concolor species complex (FCOSC) (four species). New species include Fusicolla elongata from soil (Zimbabwe), and Neocosmospora geoasparagicola from soil associated with Asparagus officinalis (Netherlands). New combinations include Neocosmospora akasia, N. awan, N. drepaniformis, N. duplosperma, N. geoasparagicola, N. mekan, N. papillata, N. variasi and N. warna. Newly validated taxa include Longinectria gen. nov., L. lagenoides, L. verticilliforme, Fusicolla gigas and Fusicolla guangxiensis. Furthermore, Fusarium rosicola is reduced to synonymy under N. brevis. Finally, the genome assemblies of Fusarium secorum (CBS 175.32), Microcera coccophila (CBS 310.34), Rectifusarium robinianum (CBS 430.91), Rugonectria rugulosa (CBS 126565), and Thelonectria blattea (CBS 952.68) are also announced her

Fusarium: more than a node or a foot-shaped basal cell

Recent publications have argued that there are potentially serious consequences for researchers in recognising distinct genera in the terminal fusarioid clade of the family Nectriaceae. Thus, an alternate hypothesis, namely a very broad concept of the genus Fusarium was proposed. In doing so, however, a significant body of data that supports distinct genera in Nectriaceae based on morphology, biology, and phylogeny is disregarded. A DNA phylogeny based on 19 orthologous protein-coding genes was presented to support a very broad concept of Fusarium at the F1 node in Nectriaceae. Here, we demonstrate that re-analyses of this dataset show that all 19 genes support the F3 node that represents Fusarium sensu stricto as defined by F. sambucinum (sexual morph synonym Gibberella pulicaris). The backbone of the phylogeny is resolved by the concatenated alignment, but only six of the 19 genes fully support the F1 node, representing the broad circumscription of Fusarium. Furthermore, a re-analysis of the concatenated dataset revealed alternate topologies in different phylogenetic algorithms, highlighting the deep divergence and unresolved placement of various Nectriaceae lineages proposed as members of Fusarium. Species of Fusarium s. str. are characterised by Gibberella sexual morphs, asexual morphs with thin- or thick-walled macroconidia that have variously shaped apical and basal cells, and trichothecene mycotoxin production, which separates them from other fusarioid genera. Here we show that the Wollenweber concept of Fusarium presently accounts for 20 segregate genera with clear-cut synapomorphic traits, and that fusarioid macroconidia represent a character that has been gained or lost multiple times throughout Nectriaceae. Thus, the very broad circumscription of Fusarium is blurry and without apparent synapomorphies, and does not include all genera with fusarium-like macroconidia, which are spread throughout Nectriaceae (e.g., Cosmosporella, Macroconia, Microcera). In this study four new genera are introduced, along with 18 new species and 16 new combinations. These names convey information about relationships, morphology, and ecological preference that would otherwise be lost in a broader definition of Fusarium. To assist users to correctly identify fusarioid genera and species, we introduce a new online identification database, Fusarioid-ID, accessible at www.fusarium.org. The database comprises partial sequences from multiple genes commonly used to identify fusarioid taxa (act1, CaM, his3, rpb1, rpb2, tef1, tub2, ITS, and LSU). In this paper, we also present a nomenclator of names that have been introduced in Fusarium up to January 2021 as well as their current status, types, and diagnostic DNA barcode data. In this study, researchers from 46 countries, representing taxonomists, plant pathologists, medical mycologists, quarantine officials, regulatory agencies, and students, strongly support the application and use of a more precisely delimited Fusarium (= Gibberella) concept to accommodate taxa from the robust monophyletic node F3 on the basis of a well-defined and unique combination of morphological and biochemical features. This F3 node includes, among others, species of the F. fujikuroi, F. incarnatum-equiseti, F. oxysporum, and F. sambucinum species complexes, but not species of Bisifusarium [F. dimerum species complex (SC)], Cyanonectria (F. buxicola SC), Geejayessia (F. staphyleae SC), Neocosmospora (F. solani SC) or Rectifusarium (F. ventricosum SC). The present study represents the first step to generating a new online monograph of Fusarium and allied fusarioid genera (www.fusarium.org)