New teleomorph combinations in the entomopathogenic genus Metacordyceps

Abstract

The genus Metacordyceps contains arthropod pathogens in Clavicipitaceae (Hypocreales) that formerly were classified in Cordyceps sensu Kobayasi et Mains. Of the current arthropod pathogenic genera of Hypocreales, the genus Metacordyceps remains one of the most poorly understood and contains a number of teleomorphic morphologies convergent with species of Cordyceps s.s. (Cordycipitaceae) and Ophiocordyceps (Ophiocordycipitaceae). Of note, the anamorph genera Metarhizium and Pochonia were found to be associated only with Metacordyceps and demonstrated to be phylogenetically informative for the clade. Several species of Cordyceps considered to have uncertain placements (incertae sedis) in the current taxonomic framework of clavicipitoid fungi were collected during field expeditions mostly in eastern Asia. Species reclassified here in Metacordyceps include Cordyceps atrovirens Kobayasi & Shimizu, Cordyceps indigotica Kobayasi & Shimizu, Cordyceps khaoyaiensis Hywel-Jones, Cordyceps kusanagiensis Kobayasi & Shimizu, Cordyceps martialis Speg., Ophiocordyceps owariensis Kobayasi, Cordyceps pseudoatrovirens Kobayasi & Shimizu and Ophicordyceps owariensis f. viridescens (Uchiy. & Udagawa) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora. Incorporation of these species in a multigene phylogenetic framework of the major clades of clavicipitoid fungi more than doubled the number of species in Metacordyceps and allowed for refinement of morphological concepts for the genus consistent with the phylogenetic structure. Based on these findings we then discuss evolution of this genus, subgeneric relationships, anamorph connections, and suggest additional species that should be confirmed for possible inclusion in Metacordyceps.

• anamorph-teleomorph connection
• arthropod pathogen
• Clavicipitaceae
• Metarhizium
• morphological plasticity
• Pochonia

Acknowledgments

The authors thank Ryan Woolverton for help with laboratory work and PCR, Tsuyoshi Hosoya for assistance with herbarium specimens and support during field collecting in Japan and Yi-Jian Yao, Jun-Zhi Qiu and Xiao-Liang Wang for support during field collecting in China. We thank members of the Japan Society for Vegetable Wasps and Plant Worms for providing specimens and access to collection sites.

This research was financially supported by the National Science Foundation in the form of a PEET grant to Joseph W. Spatafora ( DEB-0529752) and two EAPSI fellowships to Ryan M. Kepler (OISE-0714106, -0914288).