We describe a novel symbiotic association between a kinetoplastid protist,
gen. nov., sp. nov., and an intracytoplasmic bacterium, “
Pandoraea novymonadis” sp. nov., discovered as a result of a broad-scale survey of insect trypanosomatid biodiversity in Ecuador. We characterize this association by describing the morphology of both organisms, as well as their interactions, and by establishing their phylogenetic affinities. Importantly, neither partner is closely related to other known organisms previously implicated in eukaryote-bacterial symbiosis. This symbiotic association seems to be relatively recent, as the host does not exert a stringent control over the number of bacteria harbored in its cytoplasm. We argue that this unique relationship may represent a suitable model for studying the initial stages of establishment of endosymbiosis between a single-cellular eukaryote and a prokaryote. Based on phylogenetic analyses,
could be considered a proxy for the insect-only ancestor of the dixenous genus
and shed light on the origin of the two-host life cycle within the subfamily Leishmaniinae.
The parasitic trypanosomatid protist
gen. nov., sp. nov. entered into endosymbiosis with the bacterium “
Pandoraea novymonadis” sp. nov. This novel and rather unstable interaction shows several signs of relatively recent establishment, qualifying it as a potentially unique transient stage in the increasingly complex range of eukaryotic-prokaryotic relationships.