| Title: | Pyrokinin receptor silencing in females of the southern cattle tick Rhipicephalus (Boophilus) microplus is associated with a reproductive fitness cost |
| Author(s): | Wulff JP; Temeyer KB; Tidwell JP; Schlechte KG; Xiong C; Lohmeyer KH; Pietrantonio PV; |
| Address: | "Department of Entomology, Texas A&M University, College Station, TX, 77843-2475, USA. Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), 2700 Fredericksburg Road, Kerrville, TX, 78028-9184, USA. Cattle Fever Tick Research Laboratory, USDA-ARS, 22675 N. Moorefield Rd. Building 6419, Edinburg, TX, 78541-5033, USA. Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), 2700 Fredericksburg Road, Kerrville, TX, 78028-9184, USA. P.Pietrantonio@ag.tamu.edu" |
| DOI: | 10.1186/s13071-022-05349-w |
| ISSN/ISBN: | 1756-3305 (Electronic) 1756-3305 (Linking) |
| Abstract: | "BACKGROUND: Rhipicephalus microplus is the vector of deadly cattle pathogens, especially Babesia spp., for which a recombinant vaccine is not available. Therefore, disease control depends on tick vector control. However, R. microplus populations worldwide have developed resistance to available acaricides, prompting the search for novel acaricide targets. G protein-coupled receptors (GPCRs) are involved in the regulation of many physiological processes and have been suggested as druggable targets for the control of arthropod vectors. Arthropod-specific signaling systems of small neuropeptides are being investigated for this purpose. The pyrokinin receptor (PKR) is a GPCR previously characterized in ticks. Myotropic activity of pyrokinins in feeding-related tissues of Rhipicephalus sanguineus and Ixodes scapularis was recently reported. METHODS: The R. microplus pyrokinin receptor (Rhimi-PKR) was silenced through RNA interference (RNAi) in female ticks. To optimize RNAi, a dual-luciferase assay was applied to determine the silencing efficiency of two Rhimi-PKR double-stranded RNAs (dsRNA) prior to injecting dsRNA in ticks to be placed on cattle. Phenotypic variables of female ticks obtained at the endpoint of the RNAi experiment were compared to those of control female ticks (non-injected and beta-lactamase dsRNA-injected). Rhimi-PKR silencing was verified by quantitative reverse-transcriptase PCR in whole females and dissected tissues. RESULTS: The Rhimi-PKR transcript was expressed in all developmental stages. Rhimi-PKR silencing was confirmed in whole ticks 4 days after injection, and in the tick carcass, ovary and synganglion 6 days after injection. Rhimi-PKR silencing was associated with an increased mortality and decreased weight of both surviving females and egg masses (P < 0.05). Delays in repletion, pre-oviposition and incubation periods were observed (P < 0.05). CONCLUSIONS: Rhimi-PKR silencing negatively affected female reproductive fitness. The PKR appears to be directly or indirectly associated with the regulation of female feeding and/or reproductive output in R. microplus. Antagonists of the pyrokinin signaling system could be explored for tick control" |
| Keywords: | "*Acaricides/pharmacology Animals Cattle *Cattle Diseases Female Genetic Fitness *Neuropeptides RNA, Double-Stranded *Rhipicephalus/physiology *Tick Infestations/veterinary Gpcr Pyrokinin/pheromone biosynthesis-activating neuropeptide/diapause hormone (PK/;" |
| Notes: | "MedlineWulff, Juan P Temeyer, Kevin B Tidwell, Jason P Schlechte, Kristie G Xiong, Caixing Lohmeyer, Kimberly H Pietrantonio, Patricia V eng 2016-67015-24918/National Institute of Food and Agriculture/ FY19-21, FY22-23/Texas AgriLife Research/ England 2022/07/12 Parasit Vectors. 2022 Jul 11; 15(1):252. doi: 10.1186/s13071-022-05349-w" |
