title: Clarification of generic and species boundaries for Metarhizium and related fungi through multigene phylogenetics.
abstract: The genus Metarhizium historically refers to green-spored asexual insect pathogenic fungi. Through culturing and molecular methods, Metarhizium has been linked to Metacordyceps sexual states. Historically fungal nomenclature has allowed separate names for the different life stages of pleomorphic fungi. However, with the move to one name for one fungus regardless of life stage, there is a need to determine which name is correct. For Metarhizium the situation is complicated by the fact that Metacordyceps sexual states are interspersed among additional asexual genera, including Pochonia, Nomuraea and Paecilomyces. Metarhizium has priority as the earliest available name, but delimiting the boundaries of this genus remains problematic. To clarify relationships among these taxa we have obtained representative material for each genus and established a molecular dataset of the protein-coding genes BTUB, RPB1, RPB2 and TEF. The resulting phylogeny supports Metarhizium combining the majority of species recognized in Metacordyceps as well as the green-spored Nomuraea species and those in the more recently described genus Chamaeleomyces. Pochonia is polyphyletic, and we restrict the definition of this genus to those species forming a monophyletic clade with P. chlamydosporia, and the excluded species are transferred to Metapochonia gen. nov. It is our hope that this unified concept of sexual and asexual states in Metarhizium will foster advances in communication and understanding the unique ecologies of the associated species.
authors.affiliation: Systematic Mycology and Microbiology Laboratory, USDA-ARS, Bldg 010A, Beltsville, Maryland 20705 rmkepler@gmail.com.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Kepler
authors.affiliation: Biological Integrated Pest Management Research, USDA-ARS, RW Holley Center for Agriculture and Health, Ithaca, New York 14853-2901.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Humber
authors.affiliation: Systematic Mycology and Microbiology Laboratory, USDA-ARS, Bldg. 010A, Beltsville, Maryland 20705.
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Bischoff
authors.affiliation: Systematic Mycology and Microbiology Laboratory, USDA-ARS, Bldg. 010A, Beltsville, Maryland 20705.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Rehner
mesh_terms: D000818:Animals; D001483:Base Sequence; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D007313:Insecta / Q000382:microbiology; D052981:Metarhizium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000648:ultrastructure; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D016533:Mycological Typing Techniques; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013172:Spores, Fungal
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins
keywords: Metapochonia; Pochonia; entomopathogen; nematode pathogen; pleomorphic