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Ascosphaera callicarpa, a New Species of Bee-Loving Fungus, with a Key to the Genus for Europe

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We studied the bee specialist fungus Ascosphaera in wild solitary bees to investigate the diversity of the genus in nature and the ecology of these fungi with their bee hosts. A new morphologically distinctive species was discovered which also has a unique nrITS sequence. This new species, here named Ascosphaera callicarpa, is common on the larval feces of the solitary bee Chelostoma florisomne which nests in the Phragmites reeds of thatched roofs in Europe. Because collections of Ascosphaera from wild bees are scarce and because little is known about the ecology and distribution of the majority of the species in the genus, a key to the species thus far reported for Europe is included.
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... Although Bettsia also produces spore cysts and shares the same niche as saprophytic Ascosphaera species (Skou 1972;Wynns 2015), it is found in Leotiomycetes, phylogenetically far from Ascosphaera (Pitt et al. 2013). Currently, Ascosphaeraceae is classified in Onygenales as a monophyletic family with the single genus Ascosphaera (Fig. 1), and it is described with spore cysts with a double-layered wall and spore balls formed by groups of asci covered by a single membrane (Wynns et al. 2013). ...
... Members of the family have thus far only been isolated from pollen, bee larvae/cadavers or nest cells ( Supplementary Table 1; Fig. 4). They can also grow in habitats related to other pollenivorous insects and have a high sugar content (Wynns et al. 2013 (Marinho et al. 2018;Wynns et al. 2013). The presence of simple sac-like fruitbodies is a common feature among bee-related fungi and is shared by Ascosphaera (Onygenales; Spiltoir and Olive 1955), Bettsia (Leotiales; Wynns 2015) and Eremascus (Onygenales; Gueidan et al. 2008;Wijayawardene et al. 2017;Wynns 2015). ...
... Members of the family have thus far only been isolated from pollen, bee larvae/cadavers or nest cells ( Supplementary Table 1; Fig. 4). They can also grow in habitats related to other pollenivorous insects and have a high sugar content (Wynns et al. 2013 (Marinho et al. 2018;Wynns et al. 2013). The presence of simple sac-like fruitbodies is a common feature among bee-related fungi and is shared by Ascosphaera (Onygenales; Spiltoir and Olive 1955), Bettsia (Leotiales; Wynns 2015) and Eremascus (Onygenales; Gueidan et al. 2008;Wijayawardene et al. 2017;Wynns 2015). ...
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Full-text available
The order Onygenales is classified in the class Eurotiomycetes of the subphylum Pezizomycotina. Families in this order have classically been isolated from soil and dung, and two lineages contain causative agents of superficial, cutaneous and systemic infections in mammals. The ecology and habitat choices of the species are driven mainly by the keratin and cellulose degradation abilities. The present study aimed to investigate whether the ecological trends of the members of Onygenales can be interpreted in an evolutionary sense, linking phylogenetic parameters with habitat preferences, to achieve polyphasic definitions of the main taxonomic groups. Evolutionary processes were estimated by multiple gene genealogies and divergence time analysis. Previously described families, namely, Arthrodermataceae, Ajellomycetaceae, Ascosphaeraceae, Eremascaceae, Gymnoascaceae, Onygenaceae and Spiromastigoidaceae, were accepted in Onygenales, and two new families, Malbrancheaceae and Neogymnomycetaceae, were introduced. A number of species could not be assigned to any of the defined families. Our study provides a revised overview of the main lines of taxonomy of Onygenales, supported by multilocus analyses of ITS, LSU, TUB, TEF1, TEF3, RPB1, RPB2, and ribosomal protein 60S L10 (L1) (RP60S) sequences, combined with available data on ecology, physiology, morphology, and genomics.
... Although Bettsia also produces spore cysts and shares the same niche as saprophytic Ascosphaera species (Skou 1972;Wynns 2015), it is found in Leotiomycetes, phylogenetically far from Ascosphaera (Pitt et al. 2013). Currently, Ascosphaeraceae is classified in Onygenales as a monophyletic family with the single genus Ascosphaera (Fig. 1), and it is described with spore cysts with a double-layered wall and spore balls formed by groups of asci covered by a single membrane (Wynns et al. 2013). ...
... Members of the family have thus far only been isolated from pollen, bee larvae/cadavers or nest cells ( Supplementary Table 1; Fig. 4). They can also grow in habitats related to other pollenivorous insects and have a high sugar content (Wynns et al. 2013 (Marinho et al. 2018;Wynns et al. 2013). The presence of simple sac-like fruitbodies is a common feature among bee-related fungi and is shared by Ascosphaera (Onygenales; Spiltoir and Olive 1955), Bettsia (Leotiales; Wynns 2015) and Eremascus (Onygenales; Gueidan et al. 2008;Wijayawardene et al. 2017;Wynns 2015). ...
... Members of the family have thus far only been isolated from pollen, bee larvae/cadavers or nest cells ( Supplementary Table 1; Fig. 4). They can also grow in habitats related to other pollenivorous insects and have a high sugar content (Wynns et al. 2013 (Marinho et al. 2018;Wynns et al. 2013). The presence of simple sac-like fruitbodies is a common feature among bee-related fungi and is shared by Ascosphaera (Onygenales; Spiltoir and Olive 1955), Bettsia (Leotiales; Wynns 2015) and Eremascus (Onygenales; Gueidan et al. 2008;Wijayawardene et al. 2017;Wynns 2015). ...
Article
Full-text available
The order Onygenales is classifed in the class Eurotiomycetes of the subphylum Pezizomycotina. Families in this order have classically been isolated from soil and dung, and two lineages contain causative agents of superfcial, cutaneous and systemic infections in mammals. The ecology and habitat choices of the species are driven mainly by the keratin and cellulose degradation abilities. The present study aimed to investigate whether the ecological trends of the members of Onygenales can be interpreted in an evolutionary sense, linking phylogenetic parameters with habitat preferences, to achieve polyphasic defnitions of the main taxonomic groups. Evolutionary processes were estimated by multiple gene genealogies and divergence time analysis. Previously described families, namely, Arthrodermataceae, Ajellomycetaceae, Ascosphaeraceae, Eremascaceae, Gymnoascaceae, Onygenaceae and Spiromastigoidaceae, were accepted in Onygenales, and two new families, Malbrancheaceae and Neogymnomycetaceae, were introduced. A number of species could not be assigned to any of the defned families. Our study provides a revised overview of the main lines of taxonomy of Onygenales, supported by multilocus analyses of ITS, LSU, TUB, TEF1, TEF3, RPB1, RPB2, and ribosomal protein 60S L10 (L1) (RP60S) sequences, combined with available data on ecology, physiology, morphology, and genomics.
... Currently, Ascosphaeraceae is classified in the Onygenales as a monophyletic family with the single 1705 genus Ascosphaera (Fig. 1) and it is described with spore cysts with a double-layered wall and spore 1706 balls formed by groups of asci covered by a single membrane (Wynns et al. 2013). 1707 ...
... Table 1; 1709 Fig. 4). They can also grow in habitats related to other pollenivorous insects and have a high sugar 1710 content (Wynns et al. 2013). Only Ascosphaera atra, a solitary bee-related saprobe, has been isolated from grass silage, apparently outside the bee habitat (Skou 1986). ...
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The order Onygenales is classified in the class Eurotiomycetes of the subphylum Pezizomycotina. Families in this order have classically been isolated from soil and dung, and two lineages contain causative agents of superficial, cutaneous, and systemic infections in mammals. The ecology and habitat choices of the species are driven mainly by abilities of keratin- and cellulose-degradation. The present study aimed to investigate whether the ecological trends of the members of the Onygenales can be interpreted in an evolutionary sense, linking phylogenetic parameters with habitat preferences, to achieve polyphasic definitions of the main taxonomic groups. Evolutionary processes were estimated by multiple gene genealogies and divergence time analysis. Previously described families namely, Arthrodermataceae, Ajellomycetaceae, Ascosphaeraceae, Eremascaceae, Gymnoascaceae, Onygenaceae and Spiromastigaceae were accepted in the Onygenales, and two new families, Auxarthraceae and Neogymnomycetaceae were introduced. A number of species could not be assigned to any of the defined families. Our study provides a revised overview of the main lines of taxonomy of the Onygenales, supported by multilocus analyses of ITS, LSU, TUB , TEF1 , TEF3 , RPB1 , RPB2, and ribosomal protein 60S L10 (L1) ( RP60S ) sequences, combined with available data on ecology, physiology, morphology, and genomics.
... The spores pass through the intestine due to the coordinated production of extracellular enzymes, which are secreted into the environment together with the mechanical pressure of the hyphae in the exoskeleton and/or the peritrophic membrane of the intestine (Wang & Granados, 2000;Teerayut & Panuwan, 2008;Cornman et Ascosphaera apis isolated from commercial pollen al., 2012). Although the Ascosphaera species are spread throughout the hive by larva cells and feces within the brood nest (Albo et al., 2017), pollen reservoirs are known to contribute to the distribution of ascospores (Wynns et al., 2013;Pereira et al., 2019). Many winter beekeepers feed their hives commercial pollen and sugar syrup to strengthen their colonies after the season (Ahmed, 2008). ...
... strains could be explained as a deficiency in the treatment of the collected pollen. The morphological observation indicated that the size of the strains' sporocysts and the ascospores were similar to those reported in other works from both southern Argentina and other parts of the world (Albo & Reynaldi, 2010;Aronstein & Murray, 2010;Wynns et al., 2013;Chen et al., 2018;Pereira et al., 2019). The phylogenetic analysis allowed us to establish relationships between strains found in some countries and isolates of commercial pollen from Argentina. ...
Article
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In recent years, increased deforestation and replacement of areas intended for intensive cultivation have caused pathogens and parasites of Apis mellifera bees to emerge in regions where they had not previously been reported. Such is the case of the advancement of Ascosphaera apis, a fungus that causes a drop in colonies’ bee larvae population and great economic losses to beekeeping activity during severe cases. In northern Argentina, few studies have focused on this important entomopathogen. This is the first study on A. apis isolated from commercial pollen in Entre Ríos, Jujuy, and Misiones provinces, where its prevalence in bee colonies has not been reported. We identified this entomopathogen using macroscopic, microscopic, and molecular analyses, focusing on its botanical origin as a possible transmission route. We found the pathogenicity of each strain in A. mellifera bees to below 30%. The results of this study contribute to the promotion of sanitary measures that may reduce this disease’s progression in local apiaries.
... Ascosphaera spp. to grzyby początkowo kojarzone tylko z larwami pszczoły miodnej (Wynns, Jensen, Eilenberg, 2013). Niektóre gatunki Ascosphaera są patogenne i powodują grzybicę wapienną czerwiu pszczelego u pszczół formujących rodziny i u pszczół samotnic (Wynns, Jensen, Eilenberg, 2013). ...
... Ascosphaera spp. to grzyby początkowo kojarzone tylko z larwami pszczoły miodnej (Wynns, Jensen, Eilenberg, 2013). Niektóre gatunki Ascosphaera są patogenne i powodują grzybicę wapienną czerwiu pszczelego u pszczół formujących rodziny i u pszczół samotnic (Wynns, Jensen, Eilenberg, 2013). ...
... It can cause the deadly chalkbrood disease of bees (Spiltoir, 1955;Spiltoir and Olive, 1955), inflicting severe worldwide economic losses in beekeeping and seriously undermining the ability of bees to pollinate crops (Spiltoir, 1955;Spiltoir and Olive, 1955;Aronstein and Murray, 2010). In the life cycle of A. apis, spores enter the midgut of bee larvae by ingestion and remain dormant (Morse, 1978;Wynns et al., 2013). When the honeybee larvae develop to instars 4-5, the spores germinate. ...
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Ascosphaera apis spores containing a dark-colored pigment infect honeybee larvae, resulting in a large-scale collapse of the bee colony due to chalkbrood disease. However, little is known about the pigment or whether it plays a role in bee infection caused by A. apis. In this study, the pigment was isolated by alkali extraction, acid hydrolysis, and repeated precipitation. Ultraviolet (UV) analysis revealed that the pigment had a color value of 273, a maximum absorption peak at 195 nm, and a high alkaline solubility (7.67%) and acid precipitability. Further chemical structure analysis of the pigment, including elemental composition, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, mass spectrometry, and nuclear magnetic resonance (NMR), proved that it was a eumelanin with a typical indole structure. The molecular formula of melanin is C10H6O4N2, and its molecular weight is 409 Da. Melanin has hydroxyl, carboxyl, amino, and phenolic groups that can potentially chelate to metal ions. Antioxidant function analyses showed that A. apis melanin had a high scavenging activity against superoxide, hydroxyl, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, and a high reducing ability to Fe3+. Indirect immunofluorescence assay (IFA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses showed that A. apis melanin was located on the spore wall. The spore wall localization, antioxidant activity, and metal ion chelating properties of fungal melanin have been suggested to contribute to spore pathogenicity. However, further infection experiments showed that melanin-deficient spores did not reduce the mortality of bee larvae, indicating that melanin does not increase the virulence of A. apis spores. This study is the first report on melanin produced by A. apis, providing an important background reference for further study on its role in A. apis.
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Agri-environmental schemes (AES) are used to enhance pollinator diversity on agricultural farms within the UK. Though the impacts of these schemes on archetypal pollinator species such as the bumblebee ( Bombus ) and honeybee ( Apis ) are well-studied, the effects on non-target bee species like solitary bees, in the same environment, are generally lacking. One goal of AES is to alter floral provision and taxonomic composition of plant communities to provide better forage for pollinators, however, this may potentially impact other ecological communities such as fungal diversity associated with plant-bee communities. Fungi are integral in these bee communities as they can impact bee species both beneficially and detrimentally. We test the hypothesis that alteration of the environment through provision of novel plant communities has non-target effects on the fungi associated with solitary bee communities. We analyse fungal diversity and ecological networks formed between fungi and solitary bees present on 15 agricultural farms in the UK using samples from brood cells. The farms were allocated to two categories, low and high management, which differ in the number of agri-environmental measures implemented. Using internal transcribed spacer metabarcoding, we identified 456 fungal taxa that interact with solitary bees. Of these, 202 (approximately 44%) could be assigned to functional groups, the majority being pathotrophic and saprotrophic species. A large proportion was Ascosphaeraceae, a family of bee-specialist fungi. We considered the connectance, nestedness, modularity, nestedness overlap and decreasing fill, linkage density and fungal generality of the farms' bee–fungi ecological networks. We found no difference in the structure of bee–fungi ecological networks between low and high management farms, suggesting floral provision by AES has no significant impact on interactions between these two taxonomic groups. However, bee emergence was lower on the low management farms compared to high management, suggesting some limited non-target effects of AES. This study characterizes the fungal community associated with solitary bees and provides evidence that floral provision through AES does not impact fungal interactions.
Conference Paper
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Chalkbrood disease (Ascosphaera apis) is one of the important fungal diseases that cause serious economic losses to the beekeeping industry. Chalkbrood disease has a worldwide distribution also widespread in Turkey in the honeybee colonies. The aim of this study was to determine the presence of chalkbrood disease in honey bee colonies in Sivas city center and seven districts (Hafik, İmranlı, Zara, Yıldızeli, Gürün, Divriği, and Şarkışla). For this purpose, 329 beehives and honeycomb samples were obtained from 180 honey bee colonies present in Sivas city center, Hafik, İmranlı, Zara, Yıldızeli, Gürün, Divriği, and Şarkışla were researched in terms of chalkbrood disease, via visiting the beekeepers. With the current study, the chalkbrood disease was detected in seven (2.12%) of 329 beehives/honeycomb samples and in four (2.22%) of 180 honeybee colonies. However, protection and control measures should be taken to prevent chalkbrood disease. As a result, with the present research, data on the prevalence of chalkbrood disease were obtained for the first time by a field study in Sivas.
Chapter
Bees comprise a large group of over 20 000 species that show a wide range of forms, habits, plant associations, and degree of social interactions. The steep decline in managed honey bee colonies in North America and Europe since the mid 2000s has precipitated a big investment on developing a better understanding of the diversity of life history traits among the non‐Apis bees, their role in pollination services and how these species are responding to the rapid and multiple facets of environmental change. Here, I provide an overview of the evolutionary history of bees (where do they come from), their diversity (how many species and lineages), and their variation in social behavior and life cycles. Then, I discuss in what ways abiotic stressors such as land use change, pesticides, and climate warming are affecting populations of non‐Apis bees. Last, I present a summary of the diversity, transmission routes and prevalence of the most common pathogens affecting non‐Apis bees. This chapter provides a broader framework about the ecology and evolution of bees and their importance to assess and improve bee health.
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Fungi in the genus Ascosphaera (Plectomycetes: Ascosphaerales) are of agricultural and horticultural interest as they are only found, in nature, in association with social and solitary bees. To date, only one member of the genus, A. osmophila, has been described from Australia. In this paper, four new species of Ascosphaera, A. duoformis, A. flava, A. solina and A. subcuticulata, are described from Australia, together with previously unrecorded Australian isolates of A. acerosa, A. atra and the honey bee chalkbrood fungus, A. apis.
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