Metabolic disruption impacts tick fitness and microbial relationships.

Arthropod-borne microbes rely on the metabolic state of a host to cycle between evolutionarily distant species. For instance, arthropod tolerance to infection may be due to redistribution of metabolic resources, often leading to microbial transmission to mammals. Conversely, metabolic alterations aids in pathogen elimination in humans, who do not ordinarily harbor arthropod-borne microbes. To ascertain the effect of metabolism on interspecies relationships, we engineered a system to evaluate glycolysis and oxidative phosphorylation in the tick . Using a metabolic flux assay, we determined that the rickettsial bacterium and the Lyme disease spirochete , which are transstadially transmitted in nature, induced glycolysis in ticks. On the other hand, the endosymbiont which is transovarially maintained, had a minimal effect on bioenergetics. Importantly, the metabolite β-aminoisobutyric acid (BAIBA) was elevated during infection of tick cells following an unbiased metabolomics approach. Thus, we manipulated the expression of genes associated with the catabolism and anabolism of BAIBA in and detected impaired feeding on mammals, reduced bacterial acquisition, and decreased tick survival. Collectively, we reveal the importance of metabolism for tick-microbe relationships and unveil a valuable metabolite for fitness.