The ovarian transcriptome of the cattle tick, Rhipicephalus (Boophilus) microplus, feeding upon a bovine host infected with Babesia bovis

Abstract

BackgroundCattle babesiosis is a tick-borne disease of cattle with the most severe form of the disease caused by the apicomplexan, Babesia bovis. Babesiosis is transmitted to cattle through the bite of infected cattle ticks of the genus Rhipicephalus. The most prevalent species is Rhipicephalus (Boophilus) microplus, which is distributed throughout the tropical and subtropical countries of the world. The transmission of B. bovis is transovarian and a previous study of the R. microplus ovarian proteome identified several R. microplus proteins that were differentially expressed in response to infection. Through various approaches, we studied the reaction of the R. microplus ovarian transcriptome in response to infection by B. bovis.MethodsA group of ticks were allowed to feed on a B. bovis-infected splenectomized calf while a second group fed on an uninfected splenectomized control calf. RNA was purified from dissected adult female ovaries of both infected and uninfected ticks and a subtracted B. bovis-infected cDNA library was synthesized, subtracting with the uninfected ovarian RNA. Four thousand ESTs were sequenced from the ovary subtracted library and annotated.ResultsThe subtracted library dataset assembled into 727 unique contigs and 2,161 singletons for a total of 2,888 unigenes, Microarray experiments designed to detect B. bovis-induced gene expression changes indicated at least 15 transcripts were expressed at a higher level in ovaries from ticks feeding upon the B. bovis-infected calf as compared with ovaries from ticks feeding on an uninfected calf. We did not detect any transcripts from these microarray experiments that were expressed at a lower level in the infected ovaries compared with the uninfected ovaries. Using the technique called serial analysis of gene expression, 41 ovarian transcripts from infected ticks were differentially expressed when compared with transcripts of controls.ConclusionCollectively, our experimental approaches provide the first comprehensive profile of the R. microplus ovarian transcriptome responding to infection by B. bovis. This dataset should prove useful in molecular studies of host-pathogen interactions between this tick and its apicomplexan parasite.

Tick-Pathogen Interactions and Vector Competence: Identification of Molecular Drivers for Tick-Borne Diseases

“…Genes involved in immunity, stress, and defense responses showed up-regulation in response to B. bovis infection (Heekin et al, 2012), while genes encoding for calreticulin, kunitz-type serine protease inhibitors and microplusin which exhibits antimicrobial activity, were differentially expressed in B. bovis/B. bigemina infected Rhipicephalus ticks (Rachinsky et al, 2007; Antunes et al, 2012; Heekin et al, 2013; Lu et al, 2016). Tick SUB (Almazán et al, 2005) was shown to be up-regulated in B. microti inoculated intrahemocoelically into Rhipicephalus haemaphysaloides (Lu et al, 2016) and B. bigemina -infected R. microplus (Merino et al, 2013) (Figure 2D).…”

The chemosensory appendage proteome of Amblyomma americanum (Acari: Ixodidae) reveals putative odorant‐binding and other chemoreception‐related proteins

“…Transcriptomes from the R. microplus gut (Heekin et al, 2013a), ovaries (Heekin et al, 2013b), and synganglion (Guerrero et al, 2016) were previously described. The transcriptome from the fore leg (Haller's organ) (4888 sequences) was obtained by similar methods to those described in Guerrero et al (2016).…”

Anti-tick vaccines in the omics era

“…The sialotranscriptome of A. variegatum (36), A. americanum (37)(38)(39), D. variabilis (39), I. scapularis (40,41), I. ricinus (42), D. andersoni Alarcon-Chaidez; (43) and R. appendiculatus (44) have been determined. R. microplus transcriptomes of larvae (45)(46)(47)(48)(49), engorged female gut (50), ovary (51), and synganglia (52) have been reported recently. The full-length coding sequences of numerous proteins and unique protein tick protein families have been described based in these analyses and their roles during host-parasite interaction described.…”