Abstract
Nuclear-encoded small-subunit ribosomal DNA was used to examine phylogenetic relationships in Paecilomyces sensu lato. Phylogenetic analysis of the 18S nr DNA demonstrates that Paecilomyces is polyphyletic across two subclasses, Sordariomycetidae and Eurotiomycetidae. The type species, Paecilomyces variotii, and thermophilic relatives belong in the order Eurotiales (Trichocomaceae), while mesophilic species related to Paecilomyces farinosus are in the order Hypocreales (Clavicipitaceae and Hypocreaceae). One species, Paecilomyces inflatus, had affinities for the order Sordariales. Within the Eurotiales, Paecilomyces is monophyletic. Within the Hypocreales, species of Paecilomyces are polyphyletic, although the data failed to fully resolve these relationships.
This work was supported by the Biodiversity Research and Training Program in Thailand (BRT Grant No. BRT 143008) with co-financing from the National Center for Genetic Engineering and Biotechnology (BIOTEC). Angelina Kuijpers, Eric Dekker and Jos Houbraken kindly assisted with supplying strains and sequence data. Dr Richard Humber kindly supplied a Paecilomyces tenuipes strain from the ARSEF collection collected close to the type locality of Isaria tenuipes. Drs Mikako Sasa, Henning Knudsen and Thomas Læssøe kindly collected and isolated the epitype material of Isaria farinosa. We thank Dr Keith Seifert for his helpful comments to improve the manuscript.