Meeting Abstract
Ticks are obligate blood feeders but spend the vast majority of their lives off-host, where they must contend with a multitude of environmental stresses. Survival under desiccating conditions is a considerable issue for ticks and is a major determinate of habitat suitability. Despite the attention paid to water balance characteristics in ticks, little is known about the molecular and biochemical mechanisms underlying dehydration stress. To uncover specific aspects associated with dehydration exposure in ticks, we examined the transcriptomic, metabolomic, and energetic responses of the American dog tick, Dermacentor variabilis, in relation to desiccation stress. RNA sequencing was used to analyze transcriptional changes and revealed the enrichment of stress-response and proteolysis pathways as well as shifts in expression of metabolic- and feeding-related genes. NMR-based metabolomics indicated there was an accumulation of several amino acids, supporting the importance of proteolysis, and glycerol and gamma-Aminobutyric acid (GABA), suggesting these molecules may act as osmoprotectants. Finally, analysis of the energetics of dehydration demonstrated that sufficient energy stores are critical to dehydration tolerance and preliminary data suggest that protein reserves are particularly important. Overall, our results identified several candidate molecules and pathways that contribute to dehydration tolerance in ticks and lay the groundwork for future studies on stress tolerance in these important disease vectors.
