Genetic underpinnings of host manipulation byOphiocordycepsas revealed by comparative transcriptomics

AbstractThe ant-infectingOphiocordycepsfungi are globally distributed, host manipulating, specialist parasites that drive aberrant behaviors in infected ants, at a lethal cost to the host. An apparent increase in activity and wandering behaviors precedes a final summiting and biting behavior on to vegetation, positioning the manipulated ant in a site beneficial for fungal growth and transmission. Notably, acrossOphiocordycepsspecies and other known host manipulators, the molecular mechanisms underlying behavioral changes remain largely unclear. We explored possible genetic underpinnings of host manipulation by: (i)producing a hybrid assembly of theOphiocordyceps camponoti-floridanigenome, (ii) conducting laboratory infections coupled with RNAseq of bothO. camponoti-floridaniand its host,Campontous floridanus, and (iii) using these data for a comparative analysis to similar work performed inOphiocordyceps kimflemingiaeandCamponotus castaneus. We propose differentially expressed genes tied to ant neurobiology, odor response, circadian rhythms, and foraging behavior may be the result of putative fungal effectors such as enterotoxins, aflatrem, and mechanisms disrupting nutrition-sensing or caste-identity pathways.