The Occurrence of Bacterium‐like Organelles in Vesicular‐arbuscular Mycorrhizal Fungi

Macdonald, R. M.; Chandler, Muriel R.; Mosse, Barbara

doi:10.1111/j.1469-8137.1982.tb03275.x

Cited by 59 publications

(45 citation statements)

References 9 publications

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“…They seem to belong to the Gram-positive bacteria. Their ultrastructure is similar to the BLOs described in other members of the Glomales and Endogonales, like Glomus mosseae (Macdonald et al, 1982;Meier and Charvat, 1992), Gigaspora heterogama, an unidentified "white reticulate" AM fungus (Macdonald et al, 1982), Glomus caledonium (Macdonald and Chandler, 1981), Acaulospora laevis (Mosse, 1970b), Gigaspora margarita (Macdonald et al, 1982;Sward, 1981a, b, c), another unidentified AM fungus (Protzenko, 1974(Protzenko, , 1975, Endogone flammicorona (Bonfante-Fasolo and Scannerini, 1977b), Glomus versiforme (Garriock et al, 1989), a member of the Glomus fasciculatus complex (BonfanteFasolo and Scannerini, 1977a;Scannerini and BonfanteFasolo, 1982), and in undetermined members of the Glomales, forming an AM-like association with hepatophytes (Ligrone and Lopes, 1989), anthocerophytes (Ligrone, 1988) and a Lycopodium species (Schmid and Oberwinkler, 1993) (for a review of BLOs in AM fungi see Scannerini and Bonfante-Fasolo, 1992).…”

Section: Discussionmentioning

confidence: 54%

Geosiphon pyriforme, an Endosymbiotic Association of Fungus and Cyanobacteria: the Spore Structure Resembles that of Arbuscular Mycorrhizal (AM) Fungi

et al. 1994

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The zygomycete Geosiphon pyriforme is the only known endocyanosis of a fungus. The Nostoc spp. filaments are included in photosynthetically active and nitrogen fixing, multinucleated bladders, which grow on the soil surface. The spores of the fungus are white or slightly brownish. They are about 250 μm in diameter and develop singly on hyphal ends or, less frequently, intercalarly. The wall of the spores consists of a thin innermost layer, a laminated inner layer with a thickness of about 10–13 μm, and an evanescent outer layer. The laminated layer is composed of helicoidally arranged microfibrils, and is separated from the evanescent outer layer by a thin electron‐dense sublayer. Polarisation microscopy indicates the occurrence of chitin. Shape and wall ultrastructure of the Geosiphon spores and their cytoplasm resemble that of Glomus spores, but are different from that of other genera of the Glomales and Endogonales. Germination occurs by a single thick hyphal outgrowth directly through the spore wall. Like various AM forming fungi, Geosiphon pyriforme contains endocytic bacteria‐like organisms, which are not surrounded by a host membrane. Our observations indicate that Geosiphon is a potential AM fungus.

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Section: Discussionmentioning

confidence: 54%

Geosiphon pyriforme, an Endosymbiotic Association of Fungus and Cyanobacteria: the Spore Structure Resembles that of Arbuscular Mycorrhizal (AM) Fungi

et al. 1994

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“…Two types of endosymbionts are known in AMF: (i) a rod-shaped, Gram-negative beta-proteobacterium (Bonfante et al, 1994), Candidatus Glomeribacter gigasporarum (CaGg), common in several species of the family Gigasporaceae (Bianciotto et al, 2003;Mondo et al, 2012), and (ii) a coccoid bacterium displaying a homogeneous Gram-positive-like wall structure (MacDonald et al, 1982;Scannerini and Bonfante, 1991), which represents a currently undescribed taxon of Mollicutesrelated endobacteria (Mre) with a wide distribution across Glomeromycota (Naumann et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Detection of a novel intracellular microbiome hosted in arbuscular mycorrhizal fungi

et al. 2013

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Arbuscular mycorrhizal fungi (AMF) are important members of the plant microbiome. They are obligate biotrophs that colonize the roots of most land plants and enhance host nutrient acquisition. Many AMF themselves harbor endobacteria in their hyphae and spores. Two types of endobacteria are known in Glomeromycota: rod-shaped Gram-negative Candidatus Glomeribacter gigasporarum, CaGg, limited in distribution to members of the Gigasporaceae family, and coccoid Mollicutes-related endobacteria, Mre, widely distributed across different lineages of AMF. The goal of the present study is to investigate the patterns of distribution and coexistence of the two endosymbionts, CaGg and Mre, in spore samples of several strains of Gigaspora margarita. Based on previous observations, we hypothesized that some AMF could host populations of both endobacteria. To test this hypothesis, we performed an extensive investigation of both endosymbionts in G. margarita spores sampled from Cameroonian soils as well as in the Japanese G. margarita MAFF520054 isolate using different approaches (molecular phylotyping, electron microscopy, fluorescence in situ hybridization and quantitative real-time PCR). We found that a single AMF host can harbour both types of endobacteria, with Mre population being more abundant, variable and prone to recombination than the CaGg one. Both endosymbionts seem to retain their genetic and lifestyle peculiarities regardless of whether they colonize the host alone or together. These findings show for the first time that fungi support an intracellular bacterial microbiome, in which distinct types of endobacteria coexist in a single cell.

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“…Concerning the association of bacteria with fungi, bacterial endosymbiosis has been reported in some strains of Glomeromycota [e.g. Geosiphon pyriform (22), and Gigaspora and Scutellospora species (4,6,7,15)], Ascomycota [e.g. Tuber borchii (1)], Basidiomycota [e.g.…”

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confidence: 99%

Detection of Betaproteobacteria inside the Mycelium of the Fungus Mortierella elongata

et al. 2010

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Microscopic and molecular analyses showed the presence of endobacteria inside the mycelia of four out of twelve nitrous oxide (N 2 O)-producing fungal isolates identified as Mortierella elongata. The 16S rRNA gene was successfully amplified with DNA extracted directly from the endobacterium-containing fungal strains and all sequences were related to that of Candidatus Glomeribacter gigasporarum in the family Burkholderiaceae. Bacterial endotoxin was detected in the endobacterium-positive fungal strains but only trace levels were found in endobacterium-negative strains. No significant relationship was found between the fungal N 2 O-producing activity and the presence of endobacteria.Key words: endobacterium, N 2 O production, Mortierella elongata, soil fungusThe intracellular distribution of bacteria, or more specifically bacterial endosymbiosis, is known for numerous eukaryotic organisms including ciliate protozoa (25), various insects (11), a frenulata (marine invertebrate) (12), and wellknown legume roots. Concerning the association of bacteria with fungi, bacterial endosymbiosis has been reported in some strains of Glomeromycota [e.g. Geosiphon pyriform (22), and Gigaspora and Scutellospora species (4, 6, 7, 15)], Ascomycota [e.g. Tuber borchii (1)], Basidiomycota [e.g. Laccaria bicolor; (3)] and Zygomycota [e.g. Rhizopus species (10, 18)]. In our recent study, nitrous oxide (N 2 O)-producing fungal strains were isolated from upland soils and the intramycelial localization of bacterium (endobacterium) in the fungal isolates was found (Sato, Y., et al. 2008. Abstracts for the 12th International Symposium on Microbial Ecology, Cairns, Australia). The purpose of this study is to examine further the presence of endobacteria using fluorescence and electron microscopy, the amount of endotoxin, the 16S rRNA gene, and the relationship between the presence of endobacteria and fungal N 2 O-producing activity.Ten fungal strains used in this study were isolated from no-tilled, low-nitrogen input cropland soils at the Field Science Center, Ibaraki University College of Agriculture, located in the Kanto plains of Japan and were identified as phylum Zygomycota, Mortierella elongata from their morphological characteristics and their 18S-26S/28S internal transcribed spacer sequence (ITS). All of the M. elongata strains were examined for activity to produce N 2 O and found to have low activity levels during growth in cultures containing 10 mM nitrite but no activity in cultures with 10 mM nitrate (Y. Sato, T. Nishizawa, M. Umezu, K. Tsuruta, K. Narisawa, M. Komatsuzaki, N. Kaneko, H. Ohta, submitted for publication). Comparisons were made with herbarium materials, Mortierella elongata Linnemann NBRC 8570 and M. elongata MAFF 425591, obtained from the National Institute of Technology and Evaluation (NITE Biological Resource Center, Chiba, Japan), and National Institute of Agrobiological Sciences (NIAS Genebank, Ibaraki, Japan), respectively.The morphology of M. elongata strains was observed by fluorescence microscope. Briefly, ...

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The Occurrence of Bacterium‐like Organelles in Vesicular‐arbuscular Mycorrhizal Fungi

Cited by 59 publications

References 9 publications

Geosiphon pyriforme, an Endosymbiotic Association of Fungus and Cyanobacteria: the Spore Structure Resembles that of Arbuscular Mycorrhizal (AM) Fungi

Geosiphon pyriforme, an Endosymbiotic Association of Fungus and Cyanobacteria: the Spore Structure Resembles that of Arbuscular Mycorrhizal (AM) Fungi

Detection of a novel intracellular microbiome hosted in arbuscular mycorrhizal fungi

Detection of Betaproteobacteria inside the Mycelium of the Fungus Mortierella elongata

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