“Xenasmatellales”: a new order of Agaricomycetes?

The genome-based phylogeny on the Joint Genome Institute’s MycoCosm site suggests that Xenasmatella vaga represents a lineage that is not nested within any other recognized “order” of Agaricomycetes. JGI now hosts 188 species of Agaricomycetes, representing eighteen orders, so sampling is not a major concern. In the JGI tree, Xenasmatella vaga  is placed as the sister group of a large clade containing Polyporales, Agaricomycetidae, Russulales, Thelephorales, and other clades. If this is correct, the Xenasmatella vaga genome could provide important data that would address the ecological capabilities of deep backbone nodes in Agaricomycetes. This genome was produced under the auspices of the 1000 Fungal Genomes Project, with Joey Spatafora and Jon Magnuson as the PIs for the species.

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Portion of the JGI fungal phylogeny showing placement of X. vaga among the Agaricomycetes. Note support values.

Xenasmatella vaga is a representative of the “corticioid” fungi, an understudied group of Agaricomycetes with simple, resupinate fruiting bodies, which includes saprotrophs, pathogens, and ectomycorrhizal species. There are few experts on this diverse and taxonomically challenging group, which may harbor additional undiscovered major clades of Agaricomycetes.

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Species page for the X. vaga genome on MycoCosm.