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Michael J. Wingfield - One of the best experts on this subject based on the ideXlab platform.

  • the Ophiostoma clavatum species complex a newly defined group in the Ophiostomatales including three novel taxa
    Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology, 2016
    Co-Authors: Halvor Solheim, Robert Jankowiak, Riikka Linnakoski, Caterina Villari, Thomas Kirisits, Wilhelm Z De Beer, Michael J. Wingfield
    Abstract:

    Two species of blue-stain fungi with similar morphologies, Ophiostoma brunneo-ciliatum and Ophiostoma clavatum, are associates of bark beetles infesting Pinus spp. in Europe. This has raised questions whether they represent distinct taxa. Absence of herbarium specimens and contaminated or mistakenly identified cultures of O. brunneo-ciliatum and O. clavatum have accentuated the uncertainty regarding their correct identification. The aim of this study was to reconsider the identity of European isolates reported as O. brunneo-ciliatum and O. clavatum by applying DNA-based identification methods, and to provide appropriate type specimens for them. Phylogenetic analyses of the ITS, βT, TEF-1α and CAL gene sequences revealed that the investigated isolates represent a complex of seven cryptic species. The study confirmed that ITS data is insufficient to delineate species in some Ophiostoma species clusters. Lectotypes and epitypes were designated for O. clavatum and O. brunneo-ciliatum, and three new species, Ophiostoma brunneolum, Ophiostoma macroclavatum and Ophiostoma pseudocatenulatum, are described in the newly defined O. clavatum-complex. The other two species included in the complex are Ophiostoma ainoae and Ophiostoma tapionis. The results suggest co-evolution of these fungi in association with specific bark beetles. The results also confirm the identity of the fungus associated with the pine bark beetle Ips acuminatus as O. clavatum, while O. brunneo-ciliatum appears to be mainly associated with another pine bark beetle, Ips sexdentatus.

  • multigene phylogenies and morphological characterization of five new Ophiostoma spp associated with spruce infesting bark beetles in china
    Fungal Biology, 2016
    Co-Authors: Michael J. Wingfield, Xudong Zhou, Wilhelm Z De Beer
    Abstract:

    Ophiostoma spp. (Ophiostomatales, Ascomycota) are well-known fungi associated with bark beetles (Coleoptera: Scolytinae). Some of these are serious tree pathogens, while the majority is blue-stain agents of timber. In recent years, various bark beetle species have been attacking spruce forests in Qinghai province, China, causing significant damage. A preliminary survey was done to explore the diversity of the Ophiostomatoid fungal associates of these beetles. The aims of the present study were to identify and characterize new Ophiostoma spp. associated with spruce-infesting bark beetles in Qinghai Province, and to resolve phylogenetic relationships of Ophiostoma spp. related to the Chinese isolates, using multigene phylogenetic analyses. Results obtained from four gene regions (ribosomal internal transcribed spacer regions, β-tubulin, calmodulin, translation elongation factor-1α) revealed five new Ophiostoma spp. from Qinghai. These included O. nitidus sp. nov., O. micans sp. nov., and O. qinghaiense sp. nov. in a newly defined O. piceae complex. The other two new species, O. poligraphi sp. nov. and O. shangrilae sp. nov., grouped in the O. brunneo-ciliatum complex. Based on DNA sequence and morphological comparisons, we also show that O. arduennense and O. torulosum are synonyms of O. distortum, while O. setosum is a synonym of O. cupulatum.

  • the divorce of sporothrix and Ophiostoma solution to a problematic relationship
    Studies in Mycology, 2016
    Co-Authors: Z W De Beer, Tuan A Duong, Michael J. Wingfield
    Abstract:

    One of the causal agents of human sporotrichosis, Sporothrix schenckii, is the type species of the genus Sporothrix. During the course of the last century the asexual morphs of many Ophiostoma spp. have also been treated in Sporothrix. More recently several DNA-based studies have suggested that species of Sporothrix and Ophiostoma converge in what has become known as Ophiostoma s. lat. Were the one fungus one name principles adopted in the Melbourne Code to be applied to Ophiostoma s. lat., Sporothrix would have priority over Ophiostoma, resulting in more than 100 new combinations. The consequence would be name changes for several economically important tree pathogens including O. novo-ulmi. Alternatively, Ophiostoma could be conserved against Sporothrix, but this would necessitate changing the names of the important human pathogens in the group. In this study, we sought to resolve the phylogenetic relationship between Ophiostoma and Sporothrix. DNA sequences were determined for the ribosomal large subunit and internal transcribed spacer regions, as well as the beta-tubulin and calmodulin genes in 65 isolates. The results revealed Sporothrix as a well-supported monophyletic lineage including 51 taxa, distinct from Ophiostoma s. str. To facilitate future studies exploring species level resolution within Sporothrix, we defined six species complexes in the genus. These include the Pathogenic Clade containing the four human pathogens, together with the S. pallida-, S. candida-, S. inflata-, S. gossypina- and S. stenoceras complexes, which include environmental species mostly from soil, hardwoods and Protea infructescences. The description of Sporothrix is emended to include sexual morphs, and 26 new combinations. Two new names are also provided for species previously treated as Ophiostoma.

  • a diverse assemblage of Ophiostoma species including two new taxa on eucalypt trees in south africa
    Mycological Progress, 2012
    Co-Authors: Gilbert Kamgan Nkuekam, Michael J. Wingfield, Zacharias Wilhelm De Beer, Jolanda Roux
    Abstract:

    Fungi in the Ophiostomatales include important pathogens of trees as well as agents of wood stain, reducing the economic value of timber. They rely on insects, such as bark beetles, for dispersal and are commonly associated with wounds on trees. Although Ophiostoma spp. have been reported from eucalypt wood chips in South Africa, very little is known about the diversity of the Ophiostomatales, or their insect associates, on plantation-grown Eucalyptus spp. The aim of this study was to consider the diversity and distribution of the Ophiostomatales infecting fresh wounds on Eucalyptus trees in the country. Additionally, knowledge regarding their association with nitidulid beetles, which have previously been shown to carry Ophiostoma spp., was sought. Surveys were conducted in five provinces where Eucalyptus spp. are commonly grown, and the fungi collected were identified using morphological comparisons and multigene sequence phylogenies. Of the 139 isolates collected, five Ophiostoma spp. were identified including O. quercus, O. tsotsi and O. tasmaniense. These were from cut stumps as well as from the nitidulid beetles Brachypeplus depressus and Carpophilus spp. In addition, two new taxa in the O. stenoceras–Sporothrix schenckii complex were identified from Eucalyptus trees infested by Phoracantha semipunctata. The two new taxa are described as O. candidum sp. nov., and O. fumeum sp. nov., respectively. The results of this study clearly show that the diversity and ecology of Ophiostoma spp. on Eucalyptus trees in South Africa is poorly understood and that further studies are required to determine the possible economic relevance of these fungi.

  • biotic and abiotic constraints that facilitate host exclusivity of gondwanamyces and Ophiostoma on protea
    Fungal Biology, 2012
    Co-Authors: Francois Roets, Michael J. Wingfield, N Theron, L L Dreyer
    Abstract:

    Abstract Estimations of global fungal diversity are hampered by a limited understanding of the forces that dictate host exclusivity in saprobic microfungi. To consider this problem for Gondwanamyces and Ophiostoma found in the flower heads of Protea in South Africa, we determined the role of various factors thought to influence their host exclusivity. Results showed that various biotic and abiotic factors influence the growth and survival of these fungi in vitro . Monitoring temperature and relative humidity (RH) fluctuations within infructescences in vivo revealed considerable microclimatic differences between different Protea spp. Fungal growth and survival at different RH levels experienced in the field suggested that this factor does not play a major role in host exclusivity of these fungi. Maximum temperatures within infructescences and host preferences of the vectors of Gondwanamyces and Ophiostoma appear to play a substantial part in determining colonisation of Protea in general. However, these factors did not explain host exclusivity of specific fungal species towards particular Protea hosts. In contrast, differential growth of fungal species on media containing macerated tissue of Protea showed that Gondwanamyces and Ophiostoma grow best on tissue from their natural hosts. Thus, host chemistry plays a role in host exclusivity of these fungi, although some species grew vigorously on tissue of Protea spp. with which they are not naturally associated. A combination of host chemistry and temperature partially explains host exclusivity, but the relationship for these factors on the tested saprobic microfungi and their hosts is clearly complex and most likely includes combinations of various biotic and abiotic factors including those emerging from this study.

Colette Breuil - One of the best experts on this subject based on the ideXlab platform.

  • the genome and transcriptome of the pine saprophyte Ophiostoma piceae and a comparison with the bark beetle associated pine pathogen grosmannia clavigera
    BMC Genomics, 2013
    Co-Authors: Sajeet Haridas, Sepideh Massoumi Alamouti, Ye Wang, Shaun D Jackman, Rod Docking, Gordon Robertson, Inanc Birol, Jorg Bohlmann, Colette Breuil
    Abstract:

    Background Ophiostoma piceae is a wood-staining fungus that grows in the sapwood of conifer logs and lumber. We sequenced its genome and analyzed its transcriptomes under a range of growth conditions. A comparison with the genome and transcriptomes of the mountain pine beetle-associated pathogen Grosmannia clavigera highlights differences between a pathogen that colonizes and kills living pine trees and a saprophyte that colonizes wood and the inner bark of dead trees.

  • Ophiostomatoid fungi associated with the northern spruce engraver, Ips perturbatus, in western Canada
    Antonie van Leeuwenhoek, 2007
    Co-Authors: Sepideh Massoumi Alamouti, Adnan Uzunovic, Leland M Humble, Colette Breuil
    Abstract:

    A number of Ophiostomatoid fungi were isolated from the spruce-infesting bark beetle, Ips perturbatus and its galleries collected from felled spruce trees and logs in northern BC and the Yukon Territory. Isolates were identified to species using morphological characteristics, nuclear ribosomal DNA and partial β-tubulin gene sequences. Thirteen morphological and phylogenetic species were identified among the isolates. Leptographium fruticetum , Leptographium abietinum , Ophiostoma bicolor , Ophiostoma manitobense , O. piceaperdum , and eight undescribed species of the genus Ophiostoma and the anamorph genera Leptographium , Hyalorhinocladiella , Ambrosiella and Graphium . A number of these species, i.e. L. fruticetum , Hyalorhinocladiella sp. 2, O. bicolor and O. manitobense , were isolated repeatedly from I. perturbatus , while others, i.e. Graphium sp. 1 and O. piceaperdum , seemed to be␣sporadic associates. Among all the isolates, L. fruticetum had the highest relative dominance in this survey. A high frequency of occurrence of this species with the beetle may indicate a specific relationship between the two partners.

  • assessing rnai frequency and efficiency in Ophiostoma floccosum and o piceae
    Fungal Genetics and Biology, 2006
    Co-Authors: Philippe Tanguay, Siegfried Bozza, Colette Breuil
    Abstract:

    Ophiostoma species are an economically important group of saprophytic and pathogenic fungi that grow in trees or wood. Ophiostoma like O. piceae and O. floccosum produce melanin, a pigment that stains lumber and logs. We used such species as model organisms for characterizing the molecular mechanisms in fungal melanin production. Because homologous recombination is rare in the Ophiostoma, identifying gene function in this group is challenging. We addressed this by assessing RNA interference (RNAi) as an alternative to gene replacement. For this, we built different inverted repeat transgene (IRT) constructs to down-regulate the polyketide synthase (PKS1) gene of the melanin pathway in O. piceae and O. floccosum. Transformation with IRT-PKS reduced mRNA levels for the PKS1 gene, and consequently decreased pigmentation in transformants. We showed that the PKS1 RNAi efficiency was proportional to the length of the dsRNA expressed from IRT constructs. These results indicated that RNAi is an appropriate tool for functional analysis of genes in Ophiostoma.

  • Ophiostoma breviusculum sp nov Ophiostomatales ascomycota is a new species in the Ophiostoma piceae complex associated with bark beetles infesting larch in japan
    Mycologia, 2006
    Co-Authors: Wen Hsin Chung, Hayato Masuya, Yuichi Yamaoka, Adnan Uzunovic, Colette Breuil
    Abstract:

    A new species of the Ophiostoma piceae -complex was isolated from bark beetles and the insect galleries of Larix kaempferi in Japan. This species was described as Ophiostoma breviusculum. The fungus was morphologically similar to O. piceae and O. quercus. However the average length of the perithecial necks and synnemata were shorter than for O. piceae and O. quercus. Synnemata morphological characteristics also differentiated O. breviusculum from the other species of the Ophiostoma piceae - complex isolated from conifers. Mating tests demonstrated that this fungus did not produce perithecia with O. floccosum, O. piceae and O. quercus. In phylogenetic trees using rDNA ITS O. breviusculum was placed in a clade with O. canum, O. piceae and O. subalpinum, but when using β-tubulin it was placed into a separate clade.

  • diversity of fungi associated with the mountain pine beetle dendroctonus ponderosae and infested lodgepole pines in british columbia
    Fungal Diversity, 2006
    Co-Authors: Colette Breuil
    Abstract:

    The mountain pine beetle (Dendroctonus ponderosae), one of the most destructive bark beetles, has damaged large areas of lodgepole pine forests in British Columbia (Canada). It has been suggested that the beetle has a mutually beneficial relationship with the fungi that it carries. In this work, the fungal associates of the mountain pine beetle were extensively investigated. Fungi were isolated from the beetles, galleries and sapwood of infested lodgepole pines (Pinus contorta var. latifolia) at six epidemic sites in British Columbia. The isolated fungal species were more diverse than previously reported. We identified a total of 1042 isolates that belong to nine species. Among these, Ophiostoma clavigerum, an Ophiostoma minutum-like species, and Ophiostoma montium were frequently isolated. Unexpectedly, the Ophiostoma minutum-like species was found at high frequency on the mountain pine beetle. Leptographium longiclavatum, Entomocorticium dendroctoni and an unidentified species of Entomocorticium also appeared to be specifically associated with the mountain pine beetle.

Wilhelm Z De Beer - One of the best experts on this subject based on the ideXlab platform.

  • the Ophiostoma clavatum species complex a newly defined group in the Ophiostomatales including three novel taxa
    Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology, 2016
    Co-Authors: Halvor Solheim, Robert Jankowiak, Riikka Linnakoski, Caterina Villari, Thomas Kirisits, Wilhelm Z De Beer, Michael J. Wingfield
    Abstract:

    Two species of blue-stain fungi with similar morphologies, Ophiostoma brunneo-ciliatum and Ophiostoma clavatum, are associates of bark beetles infesting Pinus spp. in Europe. This has raised questions whether they represent distinct taxa. Absence of herbarium specimens and contaminated or mistakenly identified cultures of O. brunneo-ciliatum and O. clavatum have accentuated the uncertainty regarding their correct identification. The aim of this study was to reconsider the identity of European isolates reported as O. brunneo-ciliatum and O. clavatum by applying DNA-based identification methods, and to provide appropriate type specimens for them. Phylogenetic analyses of the ITS, βT, TEF-1α and CAL gene sequences revealed that the investigated isolates represent a complex of seven cryptic species. The study confirmed that ITS data is insufficient to delineate species in some Ophiostoma species clusters. Lectotypes and epitypes were designated for O. clavatum and O. brunneo-ciliatum, and three new species, Ophiostoma brunneolum, Ophiostoma macroclavatum and Ophiostoma pseudocatenulatum, are described in the newly defined O. clavatum-complex. The other two species included in the complex are Ophiostoma ainoae and Ophiostoma tapionis. The results suggest co-evolution of these fungi in association with specific bark beetles. The results also confirm the identity of the fungus associated with the pine bark beetle Ips acuminatus as O. clavatum, while O. brunneo-ciliatum appears to be mainly associated with another pine bark beetle, Ips sexdentatus.

  • multigene phylogenies and morphological characterization of five new Ophiostoma spp associated with spruce infesting bark beetles in china
    Fungal Biology, 2016
    Co-Authors: Michael J. Wingfield, Xudong Zhou, Wilhelm Z De Beer
    Abstract:

    Ophiostoma spp. (Ophiostomatales, Ascomycota) are well-known fungi associated with bark beetles (Coleoptera: Scolytinae). Some of these are serious tree pathogens, while the majority is blue-stain agents of timber. In recent years, various bark beetle species have been attacking spruce forests in Qinghai province, China, causing significant damage. A preliminary survey was done to explore the diversity of the Ophiostomatoid fungal associates of these beetles. The aims of the present study were to identify and characterize new Ophiostoma spp. associated with spruce-infesting bark beetles in Qinghai Province, and to resolve phylogenetic relationships of Ophiostoma spp. related to the Chinese isolates, using multigene phylogenetic analyses. Results obtained from four gene regions (ribosomal internal transcribed spacer regions, β-tubulin, calmodulin, translation elongation factor-1α) revealed five new Ophiostoma spp. from Qinghai. These included O. nitidus sp. nov., O. micans sp. nov., and O. qinghaiense sp. nov. in a newly defined O. piceae complex. The other two new species, O. poligraphi sp. nov. and O. shangrilae sp. nov., grouped in the O. brunneo-ciliatum complex. Based on DNA sequence and morphological comparisons, we also show that O. arduennense and O. torulosum are synonyms of O. distortum, while O. setosum is a synonym of O. cupulatum.

  • Ophiostoma species Ophiostomatales ascomycota including two new taxa on eucalypts in australia
    Australian Journal of Botany, 2011
    Co-Authors: Kamgan G Nkuekam, Michael J. Wingfield, Wilhelm Z De Beer, C L Mohammed, A J Carnegie, Geoff S Pegg, Jolanda Roux
    Abstract:

    The genus Ophiostoma accommodates ascomycetes in the order Ophiostomatales, some of which are important pathogens of trees. Although these fungi are well known in the northern hemisphere, very little is known regarding their occurrence or importance in Australia. The aim of the present study was to collect Ophiostoma spp. infecting wounds on Eucalyptus spp. in Australia, where most of these trees are native. Collections were made in three states of Australia and the isolates were identified using morphological and multigene-sequence comparisons. Of the 76 isolates collected, two previously unknown species of Ophiostoma were found and these are described here as O. tasmaniense sp. nov. and O. undulatum sp. nov. In addition, O. quercus (Georgev.) Nannf. and O. tsotsi Grobbelaar, Z.W.de Beer & M.J.Wingf. are reported for the first time from eucalypts in Australia and the distribution of Pesotum australiae Kamgan Nkuekam, Jacobs & Wingfield is expanded to include eucalypts in Tasmania. In pathogenicity tests, very small lesions were observed in both the bark and xylem of E. grandis (Hill) Maiden trees, suggesting that none of the collected species is a pathogen of Eucalyptus spp.

  • discovery of Ophiostoma tsotsi on eucalyptus wood chips in china
    Mycoscience, 2011
    Co-Authors: Joha W Grobbelaar, Michael J. Wingfield, Wilhelm Z De Beer, Xudong Zhou, Paulette Bloomer, Brenda D Wingfield
    Abstract:

    Ophiostoma species such as O. quercus are the most frequent causal agents of sapstain of freshly felled hardwood timber and pulpwood. Many species are regarded as economically important agents of wood degradation. The aim of this study was to identify a collection of Ophiostoma isolates, resembling O. quercus, found on stained Eucalyptus pulpwood chips in China. DNA sequences of the internal transcribed spacer regions, including the 5.8S region, of the ribosomal DNA, and parts of the β-tubulin and elongation factor-1α genes, revealed that the isolates were not O. quercus. Surprisingly, they represented O. tsotsi, a wound-infesting fungus recently described from hardwoods in Africa. In addition, sequence data from an isolate from agarwood in Vietnam, identified in a previous study as belonging to an unknown Pesotum species, were also shown to represent O. tsotsi. A high level of genetic variability was observed among isolates of both O. quercus and O. tsotsi. This was unexpected and suggests that both species have been present in Asia for a significant amount of time.

  • delimitation of Ophiostoma quercus and its synonyms using multiple gene phylogenies
    Mycological Progress, 2009
    Co-Authors: Joha W Grobbelaar, Michael J. Wingfield, Wilhelm Z De Beer, Dilzara N Aghayeva, Paulette Bloomer, Brenda D Wingfield
    Abstract:

    Ophiostoma quercus is a morphologically variable species that causes sapstain on mostly hardwood hosts worldwide. Several species have been suggested as synonyms of O. quercus in the past, including O. fagi, O. roboris, O. valachicum, O. kubanicum, and O. catonianum. A recent collection of isolates resembling O. quercus from Azerbaijan provided the opportunity to reconsider the accuracy of these synonymies based on morphology and DNA sequence data. Four gene regions, the ribosomal internal transcribed spacer regions including the 5.8 s gene, part of the β-tubulin gene, translation elongation factor-1α, and histone gene, were used to determine the phylogenetic relationships between the various species and isolates of different origin. In all four resulting phylogenetic trees, isolates of O. quercus, O. fagi, and O. roboris formed a single, well-supported cluster, but with some internal variation. All the other species in the analyses, including O. piceae and O. catonianum, grouped distinctly with good node support. These results thus support the synonymy of O. fagi and O. roboris with O. quercus, and confirm that O. piceae and O. catonianum are distinct taxa. Ophiostoma valachicum and O. kubanicum could not be considered due to the absence of cultures, but based on published descriptions, we argue that O. valachicum should be regarded as a valid species in need of neotypification. Ophiostoma kubanicum was never validly described and should be excluded from the list of synonyms of O. quercus.

Francois Roets - One of the best experts on this subject based on the ideXlab platform.

  • biotic and abiotic constraints that facilitate host exclusivity of gondwanamyces and Ophiostoma on protea
    Fungal Biology, 2012
    Co-Authors: Francois Roets, Michael J. Wingfield, N Theron, L L Dreyer
    Abstract:

    Abstract Estimations of global fungal diversity are hampered by a limited understanding of the forces that dictate host exclusivity in saprobic microfungi. To consider this problem for Gondwanamyces and Ophiostoma found in the flower heads of Protea in South Africa, we determined the role of various factors thought to influence their host exclusivity. Results showed that various biotic and abiotic factors influence the growth and survival of these fungi in vitro . Monitoring temperature and relative humidity (RH) fluctuations within infructescences in vivo revealed considerable microclimatic differences between different Protea spp. Fungal growth and survival at different RH levels experienced in the field suggested that this factor does not play a major role in host exclusivity of these fungi. Maximum temperatures within infructescences and host preferences of the vectors of Gondwanamyces and Ophiostoma appear to play a substantial part in determining colonisation of Protea in general. However, these factors did not explain host exclusivity of specific fungal species towards particular Protea hosts. In contrast, differential growth of fungal species on media containing macerated tissue of Protea showed that Gondwanamyces and Ophiostoma grow best on tissue from their natural hosts. Thus, host chemistry plays a role in host exclusivity of these fungi, although some species grew vigorously on tissue of Protea spp. with which they are not naturally associated. A combination of host chemistry and temperature partially explains host exclusivity, but the relationship for these factors on the tested saprobic microfungi and their hosts is clearly complex and most likely includes combinations of various biotic and abiotic factors including those emerging from this study.

  • two new Ophiostoma species from protea caffra in zambia
    Persoonia, 2010
    Co-Authors: Francois Roets, Michael J. Wingfield, Z W De Beer, Brenda D Wingfield, L L Dreyer
    Abstract:

    The genus Ophiostoma (Ophiostomatales) has a global distribution and species are best known for their association with bark beetles (Curculionidae: Scolytinae) on conifers. An unusual assemblage of these fungi is closely associated with the African endemic plant genus Protea (Proteaceae). Protea-associated Ophiostoma species are ecologically atypical as they colonise the fruiting structures of various serotinous Protea species. Seven species have been described from this niche in South Africa. It has been speculated that novel species may be present in other African countries where these host plants also occur. This view was corroborated by recent col- lections of two unknown species from Protea caffra trees in Zambia. In the present study we evaluate the species delineation of these isolates using morphological comparisons with other Protea-associated species, differential growth studies and analyses of DNA sequence data for the β-tubulin and internal transcribed spacer (ITS1, 5.8S, ITS2) regions. As a result, the species O. protea­sedis sp. nov., and O. zambiensis sp. nov. are described here as new. This study brings the number of Protea-associated Ophiostoma species to nine and highlights the need for more inclusive surveys, including additional African countries and hosts, to elucidate species diversity in this uncharacteristic niche.

  • fungal radiation in the cape floristic region an analysis based on gondwanamyces and Ophiostoma
    Molecular Phylogenetics and Evolution, 2009
    Co-Authors: Francois Roets, Michael J. Wingfield, P W Crous, L L Dreyer
    Abstract:

    Abstract The Cape Floristic Region (CFR) displays high levels of plant diversity and endemism, and has received focused botanical systematic attention. In contrast, fungal diversity patterns and co-evolutionary processes in this region have barely been investigated. Here we reconstruct molecular phylogenies using the ITS and β-tubulin gene regions of the Ophiostomatoid fungi Gondwanamyces and Ophiostoma associated with southern African Protea species. Results indicate that they evolved in close association with Protea. In contrast to Protea, Ophiostoma species migrated to the CFR from tropical and subtropical Africa, where they underwent subsequent radiation. In both Gondwanamyces and Ophiostoma vector arthropods probably facilitated long-distance migration and shorter-distance dispersal. Although ecological parameters shaped most associations between Ophiostomatoid fungi and Protea, there is congruence between fungal–host-associations and the systematic classification of Protea. These results confirm that the entire biotic environment must be considered in order to understand diversity and evolution in the CFR as a whole.

  • mite mediated hyperphoretic dispersal of Ophiostoma spp from the infructescences of south african protea spp
    Environmental Entomology, 2009
    Co-Authors: Francois Roets, Michael J. Wingfield, P W Crous, L L Dreyer
    Abstract:

    Ophiostomatoid fungi are well known as economically important pathogens and agents of timber degradation. A unique assemblage of these arthropod-associated organisms including species of Gondwanamyces G. J. Marais and M. J. Wingf., and Ophiostoma Syd. and P. Syd. occur in the floral heads (infructescences) of Protea L. species in South Africa. It has recently been discovered that Ophiostoma found in Protea flower-heads are vectored by mites (Acarina) including species of: Tarsonemus Canestrini and Fonzago, Proctolaelaps Berlese, and Trichouropoda Berlese. It is, however, not known how the mites carry the fungi between host plants. In this study, we consider two possible modes of mite dispersal. These include self-dispersal between infructescences and dispersal through insect vectors. Results showed that, as infructescences desiccate, mites self-disperse to fresh moist infructescences. Long-range dispersal is achieved through a phoretic association with three beetle species: Genuchus hottentottus (F.), Trichostetha fascicularis L., and T. capensis L. The long-range, hyperphoretic dispersal of O. splendens G. J. Marais and M. J. Wingf. and O. phasma Roets et al. seemed effective, because their hosts were colonized during the first flowering season 3–4 yr after fire.

  • Ophiostoma gemellus and sporothrix variecibatus from mites infesting protea infructescences in south africa
    Mycologia, 2008
    Co-Authors: Francois Roets, Michael J. Wingfield, Wilhelm Z De Beer, P W Crous, L L Dreyer
    Abstract:

    Ophiostoma (Ophiostomatales) represents a large genus of fungi mainly known from associations with bark beetles (Curculionidae: Scolytinae) infest- ing conifers in the northern hemisphere. Few southern hemisphere native species are known, and the five species that consistently occur in the infructescences of Protea spp. in South Africa are ecologically unusual. Little is known about the vectors of Ophiostoma spp. from Protea infructescences, however recent studies have considered the possible role of insects and mites in the distribution of these exceptional fungi. In this study we describe a new species of Ophiostoma and a new Sporothrix spp. with affinities to Ophiostoma, both initially isolated from mites associated with Protea spp. They are described as Ophiostoma gemellus sp. nov. and Sporothrix variecibatus sp. nov. based on their morphology and comparisons of DNA sequence data of the 28S ribosomal, b-tubulin and internal transcribed spacer (ITS1, 5.8S, ITS2) regions. DNA sequences of S. variecibatus were identical to those of a Sporothrix isolate obtained from Eucalyptus leaf litter in the same area in which S. variecibatus occurs in Protea infructescences. Results of this study add evidence to the view that mites are the vectors of Ophiostoma spp. that colonize Protea infructescences. They also show that DNA sequence comparisons are likely to reveal

L L Dreyer - One of the best experts on this subject based on the ideXlab platform.

  • biotic and abiotic constraints that facilitate host exclusivity of gondwanamyces and Ophiostoma on protea
    Fungal Biology, 2012
    Co-Authors: Francois Roets, Michael J. Wingfield, N Theron, L L Dreyer
    Abstract:

    Abstract Estimations of global fungal diversity are hampered by a limited understanding of the forces that dictate host exclusivity in saprobic microfungi. To consider this problem for Gondwanamyces and Ophiostoma found in the flower heads of Protea in South Africa, we determined the role of various factors thought to influence their host exclusivity. Results showed that various biotic and abiotic factors influence the growth and survival of these fungi in vitro . Monitoring temperature and relative humidity (RH) fluctuations within infructescences in vivo revealed considerable microclimatic differences between different Protea spp. Fungal growth and survival at different RH levels experienced in the field suggested that this factor does not play a major role in host exclusivity of these fungi. Maximum temperatures within infructescences and host preferences of the vectors of Gondwanamyces and Ophiostoma appear to play a substantial part in determining colonisation of Protea in general. However, these factors did not explain host exclusivity of specific fungal species towards particular Protea hosts. In contrast, differential growth of fungal species on media containing macerated tissue of Protea showed that Gondwanamyces and Ophiostoma grow best on tissue from their natural hosts. Thus, host chemistry plays a role in host exclusivity of these fungi, although some species grew vigorously on tissue of Protea spp. with which they are not naturally associated. A combination of host chemistry and temperature partially explains host exclusivity, but the relationship for these factors on the tested saprobic microfungi and their hosts is clearly complex and most likely includes combinations of various biotic and abiotic factors including those emerging from this study.

  • two new Ophiostoma species from protea caffra in zambia
    Persoonia, 2010
    Co-Authors: Francois Roets, Michael J. Wingfield, Z W De Beer, Brenda D Wingfield, L L Dreyer
    Abstract:

    The genus Ophiostoma (Ophiostomatales) has a global distribution and species are best known for their association with bark beetles (Curculionidae: Scolytinae) on conifers. An unusual assemblage of these fungi is closely associated with the African endemic plant genus Protea (Proteaceae). Protea-associated Ophiostoma species are ecologically atypical as they colonise the fruiting structures of various serotinous Protea species. Seven species have been described from this niche in South Africa. It has been speculated that novel species may be present in other African countries where these host plants also occur. This view was corroborated by recent col- lections of two unknown species from Protea caffra trees in Zambia. In the present study we evaluate the species delineation of these isolates using morphological comparisons with other Protea-associated species, differential growth studies and analyses of DNA sequence data for the β-tubulin and internal transcribed spacer (ITS1, 5.8S, ITS2) regions. As a result, the species O. protea­sedis sp. nov., and O. zambiensis sp. nov. are described here as new. This study brings the number of Protea-associated Ophiostoma species to nine and highlights the need for more inclusive surveys, including additional African countries and hosts, to elucidate species diversity in this uncharacteristic niche.

  • fungal radiation in the cape floristic region an analysis based on gondwanamyces and Ophiostoma
    Molecular Phylogenetics and Evolution, 2009
    Co-Authors: Francois Roets, Michael J. Wingfield, P W Crous, L L Dreyer
    Abstract:

    Abstract The Cape Floristic Region (CFR) displays high levels of plant diversity and endemism, and has received focused botanical systematic attention. In contrast, fungal diversity patterns and co-evolutionary processes in this region have barely been investigated. Here we reconstruct molecular phylogenies using the ITS and β-tubulin gene regions of the Ophiostomatoid fungi Gondwanamyces and Ophiostoma associated with southern African Protea species. Results indicate that they evolved in close association with Protea. In contrast to Protea, Ophiostoma species migrated to the CFR from tropical and subtropical Africa, where they underwent subsequent radiation. In both Gondwanamyces and Ophiostoma vector arthropods probably facilitated long-distance migration and shorter-distance dispersal. Although ecological parameters shaped most associations between Ophiostomatoid fungi and Protea, there is congruence between fungal–host-associations and the systematic classification of Protea. These results confirm that the entire biotic environment must be considered in order to understand diversity and evolution in the CFR as a whole.

  • mite mediated hyperphoretic dispersal of Ophiostoma spp from the infructescences of south african protea spp
    Environmental Entomology, 2009
    Co-Authors: Francois Roets, Michael J. Wingfield, P W Crous, L L Dreyer
    Abstract:

    Ophiostomatoid fungi are well known as economically important pathogens and agents of timber degradation. A unique assemblage of these arthropod-associated organisms including species of Gondwanamyces G. J. Marais and M. J. Wingf., and Ophiostoma Syd. and P. Syd. occur in the floral heads (infructescences) of Protea L. species in South Africa. It has recently been discovered that Ophiostoma found in Protea flower-heads are vectored by mites (Acarina) including species of: Tarsonemus Canestrini and Fonzago, Proctolaelaps Berlese, and Trichouropoda Berlese. It is, however, not known how the mites carry the fungi between host plants. In this study, we consider two possible modes of mite dispersal. These include self-dispersal between infructescences and dispersal through insect vectors. Results showed that, as infructescences desiccate, mites self-disperse to fresh moist infructescences. Long-range dispersal is achieved through a phoretic association with three beetle species: Genuchus hottentottus (F.), Trichostetha fascicularis L., and T. capensis L. The long-range, hyperphoretic dispersal of O. splendens G. J. Marais and M. J. Wingf. and O. phasma Roets et al. seemed effective, because their hosts were colonized during the first flowering season 3–4 yr after fire.

  • Ophiostoma gemellus and sporothrix variecibatus from mites infesting protea infructescences in south africa
    Mycologia, 2008
    Co-Authors: Francois Roets, Michael J. Wingfield, Wilhelm Z De Beer, P W Crous, L L Dreyer
    Abstract:

    Ophiostoma (Ophiostomatales) represents a large genus of fungi mainly known from associations with bark beetles (Curculionidae: Scolytinae) infest- ing conifers in the northern hemisphere. Few southern hemisphere native species are known, and the five species that consistently occur in the infructescences of Protea spp. in South Africa are ecologically unusual. Little is known about the vectors of Ophiostoma spp. from Protea infructescences, however recent studies have considered the possible role of insects and mites in the distribution of these exceptional fungi. In this study we describe a new species of Ophiostoma and a new Sporothrix spp. with affinities to Ophiostoma, both initially isolated from mites associated with Protea spp. They are described as Ophiostoma gemellus sp. nov. and Sporothrix variecibatus sp. nov. based on their morphology and comparisons of DNA sequence data of the 28S ribosomal, b-tubulin and internal transcribed spacer (ITS1, 5.8S, ITS2) regions. DNA sequences of S. variecibatus were identical to those of a Sporothrix isolate obtained from Eucalyptus leaf litter in the same area in which S. variecibatus occurs in Protea infructescences. Results of this study add evidence to the view that mites are the vectors of Ophiostoma spp. that colonize Protea infructescences. They also show that DNA sequence comparisons are likely to reveal