Diversity and function of fungi associated with the fungivorous millipede, Brachycybe lecontii.

Fungivorous millipedes (subterclass Colobognatha) likely represent some of the earliest known mycophagous terrestrial arthropods, yet their fungal partners remain elusive. Here we describe relationships between fungi and the fungivorous millipede, Brachycybe lecontii. Their fungal community is surprisingly diverse, including 176 genera, 39 orders, four phyla, and several undescribed species. Of particular interest are twelve genera conserved across wood substrates and millipede clades that comprise the core fungal community of B. lecontii. Wood decay fungi, long speculated to serve as the primary food source for Brachycybe species, were absent from this core assemblage and proved lethal to millipedes in pathogenicity assays while entomopathogenic Hypocreales were more common in the core but had little effect on millipede health. This study represents the first survey of fungal communities associated with any colobognath millipede, and these results offer a glimpse into the complexity of millipede fungal communities.

Psychoactive plant- and mushroom-associated alkaloids from two behavior modifying cicada pathogens.

Entomopathogenic fungi routinely kill their hosts before releasing infectious spores, but a few species keep insects alive while sporulating, which enhances dispersal. Transcriptomics- and metabolomics-based studies of entomopathogens with post-mortem dissemination from their parasitized hosts have unraveled infection processes and host responses. However, the mechanisms underlying active spore transmission by Entomophthoralean fungi in living insects remain elusive. Here we report the discovery, through metabolomics, of the plant-associated amphetamine, cathinone, in four Massospora cicadina-infected periodical cicada populations, and the mushroom-associated tryptamine, psilocybin, in annual cicadas infected with Massospora platypediae or Massospora levispora, which likely represent a single fungal species. The absence of some fungal enzymes necessary for cathinone and psilocybin biosynthesis along with the inability to detect intermediate metabolites or gene orthologs are consistent with possibly novel biosynthesis pathways in Massospora. The neurogenic activities of these compounds suggest the extended phenotype of Massospora that modifies cicada behavior to maximize dissemination is chemically-induced.

Enhanced hypovirus transmission by engineered super donor strains of the chestnut blight fungus, Cryphonectria parasitica, into a natural population of strains exhibiting diverse vegetative compatibility genotypes.

Horizontal transmission of virulence attenuating hypoviruses of Cryphonectria parasitica is restricted by an allorecognition system termed vegetative incompatibility (vic). A super donor formulation of two engineered C. parasitica strains (SD328/SD82) with gene disruptions at four of six vic loci transmitted hypovirus to strains in the laboratory independent of vic genotype. We now report the transmission of hypovirus by the SD328/82 formulation to a diverse, natural C. parasitica population infecting American chestnut in a forest setting. Hypovirulent (HV) isolates were recovered from 94% of cankers treated with the hypovirus-infected SD328/82 formulation compared to 51% of cankers treated with a hypovirus-infected EU5/6 formulation (strains having the same vic genotypes as SD strains but lacking vic gene disruptions). Overall, the SD328/82 formulation transmitted hypovirus into more divergent vic genotypes compared to the EU5/6 formulation. These results demonstrate the SD328/82 formulation can serve as an enhanced hypovirus vector for highly divergent C. parasitica populations.