Molecular phylogenetic study of a termite pathogen Cordycepioideus bisporus

The termite pathogen Cordycepioideus bisporus is characterized by perithecia produced in a Cordyceps-like stroma, ascospores that are dark, thick-walled and 8-15 septate at maturity, and a Hirsutella anamorph. The genus traditionally has been placed in the Hypocreales on the basis of purported apical paraphyses and immature ascospore features; however, phylogenetic analyses of partial sequences of the nuclear small and large subunit ribosomal DNA showed a close relationship between C. bisporus and clavicipitaceous ascomycetes, which is in agreement with a newer understanding of morphological characters of this species. Hirsutella thompsonii was the sister taxon to C. bisporus, and several insect parasitic species of Cordyceps also showed close relationships to C. bisporus and H. thompsonii. The results of this study suggest strongly that the genus Cordycepioideus belongs within the Clavicipitaceae, not with other hypocrealean species where the genus originally was placed.