Transcriptome of the entomopathogenic fungus, Entomophthora muscae, during behavioural manipulation of ‘zombie’-flies (Musca domestica). E. muscae ARSEF13376 transcriptome

The basal fungus Entomophthora muscae is an obligate insect pathogen specific to adult dipterans such as Musca domestica. It is ostensibly regarded as a parasite that induces aberrant behaviour in the host species which is adaptive to the fungus at the expense of the host. Specifically, during the later stages of infection flies exhibit a behaviour sequence just prior to death which is considered to aid in the transmission of fungal spores. The timing of this phenomenon has been shown previously to be governed in a “gated-pattern” under a circadian rhythm, whereby an unknown condition has to be met by a specific time each day before the behaviour sequence is triggered. A dual RNA sequencing experiment was conducted on infected houseflies collected at various stages of infection, including immediately before and after behaviour manipulation, to characterise the system and elucidate molecular mechanisms in the fungus that are differentially expressed between these stages. Gene set enrichment analysis revealed a suite of M16 metalloproteases upregulated just prior to host manipulation, and trypsin-like serine proteases that were upregulated just after. The MAPK signal transduction pathway was also differentially expressed during this time, which is a known precursor to filamentous/invasive growth in fungi such as Saccharomyces cerevisiae following resource depletion.