Journal Article

Silencing expression of the Rhipicephalus microplus vitellogenin receptor gene blocks Babesia bovis transmission and interferes with oocyte maturation

Suarez, Carlos E., Hussein, Hala E., Scoles, Glen A., Taus, Naomi S., Ueti, Massaro W., Johnson, Wendell C.

2019

Overview

Background Rhipicephalus microplus is an efficient biological vector of Babesia bovis , a causative agent of bovine babesiosis. Babesia bovis is passed transovarially to the next generation of ticks, which then transmit the parasite to naïve animals. Due to the importance of the R. microplus ovary for tick reproduction and transmission of B. bovis , we investigated the hypothesis that silencing vitellogenin receptor gene expression in the ovary during tick feeding on B. bovis -infected cattle would affect parasite transmission to the next generation of ticks. Results Silencing expression of the vitellogenin receptor in the ovary by RNA interference, resulted in reduced tick fertility. We observed reduced egg production (i.e. reduced weight of eggs), a lower rate of embryonic development, and a reduction in hatching. Analysis of individual larvae by PCR confirmed that RNAi mediated downregulation of the R. microplus vitellogenin receptor and also interfered with transovarial transmission of B. bovis . None of the larvae (0/58) from the RmVgR dsRNA-injected group were PCR-positive, whereas 12% (7/58) and 17% (10/58) of larvae from the non-injected and buffer-injected control groups, respectively, were infected with B. bovis . Conclusions The combined effects of reduced fecundity and reduced infection in surviving larvae resulting from silencing indicate that vitellogenin receptor is essential for tick reproduction and may play a vital role in B. bovis transmission.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Arachnids / Babesia / Babesia bovis / Babesiosis / Beef cattle / Biochemistry / Biological vectors / Biomedical and Life Sciences / Biomedicine / Blood proteins / Cattle / Disease transmission / DNA / Double-stranded RNA / Egg industry / Egg production / Eggs / Embryogenesis / Embryonic development / Embryonic growth stage / Embryos / Entomology / etiological agents / Fecundity / Females / Fertility / Gene expression / Genes / Genetic aspects / Genetic engineering / Genomes / Hatching / Hypotheses / Infectious Diseases / Larvae / Maturation / Nucleic acids / Nucleotide sequence / Oocytes / Ovaries / Parasites / Parasitological research / Parasitology / PCR / Physiological aspects / Prevention / Receptors / Reproduction / Rhipicephalus microplus / Ribonucleic acid / RNA / RNA interference / RNA-mediated interference / Short Report / Survival / Tick-borne diseases / Ticks / transovarial transmission / Tropical Medicine / Veterinary Medicine/Veterinary Science / Virology / Vitellogenesis / Vitellogenin / Vitellogenin receptor / Weight reduction