Development of antisense tools to study Bodo saltans and its intracellular symbiont

Obligate symbioses are common in nature and present a particular challenge for functional genetic analysis. In many cases, the host is a non-model species with poor tools for genetic manipulation and the symbiont cannot be cultured or its gene expression manipulated to investigate function. Here we investigated the potential for using antisense inhibition to analyse host and symbiont gene function within an obligate aquatic symbiosis. We focused on the kinetoplastid host Bodo saltans and its bacterial symbiont, C andidatus Bodocaedibacter vickermanii, a member of Rickettsiales . We conclude that antisense inhibition is not feasible in the B. saltans and its symbiont, as the holobiont feeds on the antisense molecules – and increases in numbers – upon treatment with the antisense construct. Although our approach has proven unsuccessful, we have developed an array of protocols which can be used to study the biology of this microeukaryote and its microbial associates.