An insight into the ovary and midgut transcriptome of Dermacentor nitens tick.

The tropical horse tick, Dermacentor nitens, is a one-host hard tick widely distributed across tropical and subtropical regions of the Americas, where it primarily parasitizes horses and occasionally cattle and other livestock. This species is of veterinary importance due to its role as a vector of Babesia caballi, the causative agent of equine piroplasmosis. Despite its significance, genomic resources for D. nitens remain scarce, limiting molecular and functional studies. Here, we present the most comprehensive transcriptome assembly of D. nitens to date, encompassing midgut and ovary transcriptomes during the rapid phase of blood feeding. Using deep sequencing approaches, we identified and annotated a large repertoire of transcripts expressed during blood feeding and reproduction, processes central to tick survival and pathogen transmission. To further facilitate gene discovery in D. nitens, we conducted orthology searches against annotated transcripts from the genomes of Dermacentor albipictus, Dermacentor andersoni, Dermacentor silvarum, Dermacentor variabilis, Hyaloma asiaticum, Haemaphysalis longicornis, Ixodes scapularis, Ixodes persulcatus, Rhipicephalus microplus, and Rhipicephalus sanguineus. Our dataset provides new insights into midgut and ovary physiology, including genes associated with blood meal digestion and oogenesis, which are critical for reproduction and life cycle progression. These findings expand the molecular toolkit available for D. nitens, enabling future studies on tick physiology, evolution, and vector competence. Moreover, this resource offers a framework for comparative analyses with other Dermacentor species of medical relevance, thereby advancing our understanding of conserved biological mechanisms underlying feeding, reproduction, and pathogen transmission.