Novel symbionts and potential human pathogens excavated from argasid tick microbiomes that are shaped by dual or single symbiosis.

Research on vector-associated microbiomes has been expanding due to increasing emergence of vector-borne pathogens and awareness of the importance of symbionts in the vector physiology. However, little is known about microbiomes of argasid (or soft-bodied) ticks due to limited access to specimens. We collected four argasid species (, , , and ) from the nests or burrows of their vertebrate hosts. One laboratory-reared argasid species ( was also included. Attempts were then made to isolate and characterize potential symbionts/pathogens using arthropod cell lines. Microbial community structure was distinct for each tick species. was detected as the predominant symbiont in four tick species where dual symbiosis between and or and was observed in and , respectively. Of note, lacked and instead had and Thiotrichales as alternative symbionts. Our study found strong correlation between tick species and life stage. We successfully isolated and characterized potential pathogens of genera and . The results suggest that there is no consistent trend of microbiomes in relation to tick life stage that fit all tick species and that the final interpretation should be related to the balance between environmental bacterial exposure and endosymbiont ecology. Nevertheless, our findings provide insights on the ecology of tick microbiomes and basis for future investigations on the capacity of argasid ticks to carry novel pathogens with public health importance.