Ultrastructural and molecular phylogenetic delineation of a new order, the Rhizophydiales (Chytridiomycota)

Letcher, Peter M.; Powell, Martha J.; Churchill, Perry F.; Chambers, James G.

doi:10.1016/j.mycres.2006.06.011

Cited by 148 publications

(86 citation statements)

References 24 publications

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“…The remainder of the backbone was not strongly supported. However, distinct and recognizable monophyletic groups in the inferred phylogeny are congruent with major clades in Chytridiomycota and Neocallimastigomycota (James et al 2006a,b) that have been previously delineated, including Spizellomycetales (Barr 1980), Rhizophydiales (Letcher et al 2006), Rhizophlyctidales (Letcher et al 2008b), Cladochytriales (MozleyStandridge et al 2009), Lobulomycetales ), and Chytridiales (Vélez et al 2011). Half of the zoosporic fungal sequences obtained grouped within previously delineated orders of Chytridiomycota, (i.e.…”

Section: Zoosporic Fungal Diversity and Phylogenymentioning

confidence: 75%

Temporal variation of the small eukaryotic community in two freshwater lakes: emphasis on zoosporic fungi

Lefèvre¹,

Letcher²,

Powell³

2012

Aquat. Microb. Ecol.

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Section: Zoosporic Fungal Diversity and Phylogenymentioning

confidence: 75%

Temporal variation of the small eukaryotic community in two freshwater lakes: emphasis on zoosporic fungi

Lefèvre¹,

Letcher²,

Powell³

2012

Aquat. Microb. Ecol.

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Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

“…Maturation of an endobiotic Bd zoosporangium culminates in cleaving of zoosporangial contents into zoospores, formation of 1 or more zoosporedischarge papillae leading to the surface of the host or into intercellular spaces, and release of zoospores (Berger et al 2005). Bd is the only chytrid known to parasitize vertebrate hosts and is one of few endobiotic members of order Rhizophydiales (Letcher et al 2006).Nonlethal Bd infections in the bullfrog Lithobates catesbeianus are well-documented (Daszak et al 2004). In contrast, the wood frog L. sylvaticus can die from chytridiomycosis at young post-metamorphic stages under laboratory conditions (Searle et al 2011, Gahl et al 2012.…”

mentioning

confidence: 99%

Host invasion by Batrachochytrium dendrobatidis: fungal and epidermal ultrastructure in model anurans

Greenspan¹,

Longcore²,

Calhoun³

2012

Dis. Aquat. Org.

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The chytridiomycete fungus Batrachochytrium dendrobatidis (Bd) colonizes mouthparts of amphibian larvae and superficial epidermis of post-metamorphic amphibians, causing the disease chytridiomycosis. Fungal growth within host cells has been documented by light and transmission electron microscopy; however, entry of the fungus into host cells has not. Our objective was to document how Bd enters host cells in the wood frog Lithobates sylvaticus, a species at high mortality risk for chytridiomycosis, and the bullfrog L. catesbeianus, a species at low mortality risk for chytridiomycosis. We inoculated frogs and documented infection with transmission electron microscopy. Zoospores encysted on the skin surface and produced morphologically similar germination tubes in both host species that penetrated host cell membranes and enabled transfer of zoospore contents into host cells. Documenting fungal and epidermal ultrastructure during host invasion furthers our understanding of Bd development and the pathogenesis of chytridiomycosis. KEY WORDS: Chytridiomycosis · Morphology · Transmission electron microscopy · Lithobates catesbeianus · Lithobates sylvaticus Resale or republication not permitted without written consent of the publisherDis Aquat Org 100: [201][202][203][204][205][206][207][208][209][210] 2012 scopically, excessive skin sloughing, lethargy, anorexia, loss of righting reflex, and abnormal posture may be observed (Nichols et al. 2001, Daszak et al. 2004) but often not until immediately before death (Bradley et al. 2002, Parker et al. 2002. Proximate cause of death is inhibition of electrolyte transport across epidermis and subsequent disruption of cardiac electrical activity (Voyles et al. 2009).The asexual life cycle of Bd consists of a motile zoospore stage and a stationary thallus stage (Berger et al. 2005). Zoospores are flagellated and are not bounded by a cell wall. After a motile period, usually lasting ≤24 h, a zoospore encysts (i.e. attaches to a substrate, retracts the flagellum, and forms a wall of chitin around the spore body). Morphology after encystment depends on substrate type. On nutrient media, an encysted zoospore develops into a single or colonial (internally divided) zoosporangium (endogenous growth); root-like rhizoids originating from 1 or more points on the zoosporangium may be numerous . In an amphibian host, cellular contents of a superficially encysted zoospore leave the cyst and enter a host cell (exogenous growth), inside which a single or colonial zoosporangium develops; rhizoids are usually less abundant than on nutrient media (Berger et al. 2005). The specifics of amphibian host invasion by Bd (i.e. the morphological process by which zoospore contents are transferred from a cyst into a host cell) have not been reported. In other chytrid species with known developmental morphologies (saprophytes and patho gens of plants, algae, protists, and invertebrates), endobiotic (i.e. intracellular) growth of a thallus is initiated when a protrusion of the zoospore cyst wall e...

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“…Letcher et al 2006, Simmons et al 2009). Based on this approach, Bd is currently assigned to a group of primarily saprobic species, the Rhizophydiales (Letcher et al 2006). Most members of the Rhizophydiales develop only endogenously (the nucleus remains in the zoospore cyst and the cyst expands to form the zoosporangium).…”

Section: Phylogenetic Placementmentioning

confidence: 99%

A molecular perspective: biology of the emerging pathogen Batrachochytrium dendrobatidis

Rosenblum

Fisher

James³

et al. 2009

Dis. Aquat. Org.

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Ten years after the first discovery of the chytrid pathogen Batrachochytrium dendrobatidis (Bd), the catastrophic effect of Bd on wild amphibian populations is indisputable. However, a number of persistent questions remain about Bd's origin and mechanisms of pathogenicity. Here we discuss the promise of genetic and genomic tools for answering these previously intractable questions about the biology and evolutionary history of Bd. Full genomes of 2 Bd strains have recently been sequenced, and Bd research on this species using population genetics, phylogenetics, proteomics, comparative genomics and functional genomics is already underway. We review some of the insights gleaned from the first studies using these genome-scale approaches focusing particularly on Bd's genomic architecture, patterns of global genetic variation, virulence factors and genetic interactions with hosts. Avenues of future research promise to be particularly fruitful and highlight the need for integrative studies that unite genetic, ecological and spatial data in both Bd and its amphibian hosts. KEY WORDS:Genetics · Genomics · Ecological genomics · Pathogenicity · Chytrid · Batrachochytrium dendrobatidis Resale or republication not permitted without written consent of the publisherContribution to DAO Special 4 'Chytridiomycosis: an emerging disease'

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Ultrastructural and molecular phylogenetic delineation of a new order, the Rhizophydiales (Chytridiomycota)

Cited by 148 publications

References 24 publications

Temporal variation of the small eukaryotic community in two freshwater lakes: emphasis on zoosporic fungi

Temporal variation of the small eukaryotic community in two freshwater lakes: emphasis on zoosporic fungi

Host invasion by Batrachochytrium dendrobatidis: fungal and epidermal ultrastructure in model anurans

A molecular perspective: biology of the emerging pathogen Batrachochytrium dendrobatidis

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