9 research outputs found
Phylogenetic classification of Cordyceps and the clavicipitaceous fungi
Cordyceps, comprising over 400 species, was historically
classified in the Clavicipitaceae, based on cylindrical asci,
thickened ascus apices and filiform ascospores, which often disarticulate into
part-spores. Cordyceps was characterized by the production of
well-developed often stipitate stromata and an ecology as a pathogen of
arthropods and Elaphomyces with infrageneric classifications
emphasizing arrangement of perithecia, ascospore morphology and host
affiliation. To refine the classification of Cordyceps and the
Clavicipitaceae, the phylogenetic relationships of 162 taxa were
estimated based on analyses consisting of five to seven loci, including the
nuclear ribosomal small and large subunits (nrSSU and
nrLSU), the elongation factor 1α (tef1), the largest
and the second largest subunits of RNA polymerase II (rpb1 and
rpb2), β-tubulin (tub), and mitochondrial ATP6
(atp6). Our results strongly support the existence of three
clavicipitaceous clades and reject the monophyly of both Cordyceps
and Clavicipitaceae. Most diagnostic characters used in current
classifications of Cordyceps (e.g., arrangement of perithecia,
ascospore fragmentation, etc.) were not supported as being phylogenetically
informative; the characters that were most consistent with the phylogeny were
texture, pigmentation and morphology of stromata. Therefore, we revise the
taxonomy of Cordyceps and the Clavicipitaceae to be
consistent with the multi-gene phylogeny. The family Cordycipitaceae
is validated based on the type of Cordyceps, C. militaris,
and includes most Cordyceps species that possess brightly coloured,
fleshy stromata. The new family Ophiocordycipitaceae is proposed
based on Ophiocordyceps Petch, which we emend. The majority of
species in this family produce darkly pigmented, tough to pliant stromata that
often possess aperithecial apices. The new genus Elaphocordyceps is
proposed for a subclade of the Ophiocordycipitaceae, which includes
all species of Cordyceps that parasitize the fungal genus
Elaphomyces and some closely related species that parasitize
arthropods. The family Clavicipitaceae s. s. is emended and
includes the core clade of grass symbionts (e.g., Balansia,
Claviceps, Epichloë, etc.), and the entomopathogenic
genus Hypocrella and relatives. In addition, the new genus
Metacordyceps is proposed for Cordyceps species that are
closely related to the grass symbionts in the Clavicipitaceae s.
s. Metacordyceps includes teleomorphs linked to
Metarhizium and other closely related anamorphs. Two new species are
described, and lists of accepted names for species in Cordyceps,
Elaphocordyceps, Metacordyceps and Ophiocordyceps
are provided
Towards a phylogenetic classification of Cordyceps: ITS nrDNA sequence data confirm divergent lineages and paraphyly
Biological and molecular studies on invertebrate-pathogenic fungi (Clavicipitaceae, ascomycotina) of Thailand
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