Molecular Phylogenetics and Estimation of Evolutionary Divergence and Biogeography of the Family Cordycipitaceae (Ascomycota, Hypocreales).

Abstract

The Cordycipitaceae family of insecticidal fungi is widely distributed in nature, is the most complex in the order Hypocreales (Ascomycota), with members displaying a diversity of morphological characteristics and insect host ranges. Based on Bayesian evolutionary analysis of five genomic loci(the small subunit of ribosomal RNA (SSU) gene, the large subunit of ribosomal RNA (LSU) gene, the translation elongation factor 1-α (tef1-α) gene, the largest subunit of RNA polymerase II (rpb1), and the second largest subunit of RNA polymerase II (rpb2), we inferred the divergence times for members of the Cordycipitaceae, improving the internal phylogeny of this fungal family. Molecular clock analyses indicate that the ancestor of Akanthomyces sensu lato occurred in the Paleogene period (34.57 Mya, 95% HPD: 31.41-37.67 Mya), and that most species appeared in the Neogene period. The historical biogeography of Akanthomyces sensu lato was reconstructed using reconstructing ancestral state in phylogenies (RASP) analysis, indicating that it most likely originated in Asia. Combined morphological characterization and phylogenetic analyses were used to identify and taxonomically place five species within Cordycipitaceae. These include the following: (i) two new species, namely Akanthomyces baishanensis sp. nov. and Samsoniella sanmingense sp. nov., (ii) a new record species isolated from infected Lepidopteran host, Blackwellomyces lateris, (iii) a new record species in the genus Niveomyces, with sporothrix-like asexual morphs, namely N. multisynnematus, isolated from dipteran insects (flies), and (iv) a known species of the (hyper-) mycoparasite, Liangia sinensis, isolated from the fungus Ophiocordyceps globiceps (Ophiocordycipitaceae) growing on a dipteran host. Our data provide a significant addition to the diversity, ecology, and evolutionary aspects of the Cordycipitaceae.