Ancestral predisposition toward a domesticated lifestyle in the termite-cultivated fungus Termitomyces.

The ancestor of termites relied on gut symbionts for degradation of plant material, an association that persists in all termite families.1,2 However, the single-lineage Macrotermitinae has additionally acquired a fungal symbiont that complements digestion of food outside the termite gut.3 Phylogenetic analysis has shown that fungi grown by these termites form a clade-the genus Termitomyces-but the events leading toward domestication remain unclear.4 To address this, we reconstructed the lifestyle of the common ancestor of Termitomyces using a combination of ecological data with a phylogenomic analysis of 21 related non-domesticated species and 25 species of Termitomyces. We show that the closely related genera Blastosporella and Arthromyces also contain insect-associated species. Furthermore, the genus Arthromyces produces asexual spores on the mycelium, which may facilitate insect dispersal when growing on aggregated subterranean fecal pellets of a plant-feeding insect. The sister-group relationship between Arthromyces and Termitomyces implies that insect association and asexual sporulation, present in both genera, preceded the domestication of Termitomyces and did not follow domestication as has been proposed previously. Specialization of the common ancestor of these two genera on an insect-fecal substrate is further supported by similar carbohydrate-degrading profiles between Arthromyces and Termitomyces. We describe a set of traits that may have predisposed the ancestor of Termitomyces toward domestication, with each trait found scattered in related taxa outside of the termite-domesticated clade. This pattern indicates that the origin of the termite-fungus symbiosis may not have required large-scale changes of the fungal partner.

Five new species of entomopathogenic fungi from the Amazon and evolution of neotropical Ophiocordyceps.

The neotropical biogeographic zone is a 'hot spot' of global biodiversity, especially for insects. Fungal pathogens of insects appear to track this diversity. However, the integration of this unique component of fungal diversity into molecular phylogenetic analyses remains sparse. The entomopathogenic fungal genus Ophiocordyceps is species rich in this region with the first descriptions dating to the early nineteenth century. In this study, material from various ecosystems throughout Colombia and Ecuador was examined. Molecular phylogenetic analyses of five nuclear loci including SSU, LSU, TEF, RPB1, and RPB2 were conducted alongside a morphological evaluation. Thirty-five specimens were examined representing fifteen different species of Ophiocordyceps, and five new species, Ophiocordyceps blattarioides, Ophiocordyceps tiputini, Ophiocordyceps araracuarensis, Ophiocordyceps fulgoromorphila, and Ophiocordyceps evansii, were described. An accurate identification of the host allowed us to conclude that host identity and host habitat are positively correlated with phylogenetic species of Ophiocordyceps and are probably strong drivers for speciation of neotropical entomopathogenic fungi.