Phylogenetic analysis of nuclear ribosomal DNA places the nematode parasite, Drechmeria coniospora, in Clavicipitaceae

The nematode endoparasite, Drechmeria coniospora, was originally described by Drechsler and placed in the hyphomycete form genus Meria, together with Meria laricis, a foliar parasite of Larix (Pinaceae). Although both species produce 1–celled hyaline conidia from serial phialides on hyphal conidiomata, the new genus Drechmeria was proposed subsequently to accommodate the nematode parasite based on pure culture studies, ecological differences, and having integrated phialides compared to the mainly discrete phialides of M. laricis. Morphological characteristics and phylogenetic analysis of nuclear ribosomal DNA (nrDNA) support the affinity of Meria laricis to the inoperculate discomycete genus of foliar parasites, Rhabdocline. Small subunit and ITS region sequences from nrDNA were determined from an accession of D. coniospora that continued to produce diagnostic features in culture. BLAST comparisons of the sequences to nucleotide databases revealed high similarities to accessions from the perithecial ascomycete order Hypocreales. Separate phylogenetic analyses were conducted using ITS region sequences from Hypocrealean species and partial sequences from the small subunit of species representing perithecial ascomycetes and inoperculate discomycetes. Analyses placed Drechmeria in the hypocrealean family, Clavicipitaceae. Drechmeria coniospora shares the ecological strategy of animal parasitism also exhibited by some members of Clavicipitaceae. These findings support the separation of the anamorphic fungi Drechmeria and Meria into distinct genera and indicate that there is no close phylogenetic relationship between them.