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Meki IK, Huditz HI, Strunov A, van der Vlugt RAA, Kariithi HM, Rezapanah M, Miller WJ, Vlak JM, van Oers MM, Abd-Alla AMM. Characterization and Tissue Tropism of Newly Identified Iflavirus and Negeviruses in Glossina morsitans morsitans Tsetse Flies. Viruses 2021; 13:v13122472. [PMID: 34960741 PMCID: PMC8704047 DOI: 10.3390/v13122472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/03/2021] [Accepted: 12/07/2021] [Indexed: 11/26/2022] Open
Abstract
Tsetse flies cause major health and economic problems as they transmit trypanosomes causing sleeping sickness in humans (Human African Trypanosomosis, HAT) and nagana in animals (African Animal Trypanosomosis, AAT). A solution to control the spread of these flies and their associated diseases is the implementation of the Sterile Insect Technique (SIT). For successful application of SIT, it is important to establish and maintain healthy insect colonies and produce flies with competitive fitness. However, mass production of tsetse is threatened by covert virus infections, such as the Glossina pallidipes salivary gland hypertrophy virus (GpSGHV). This virus infection can switch from a covert asymptomatic to an overt symptomatic state and cause the collapse of an entire fly colony. Although the effects of GpSGHV infections can be mitigated, the presence of other covert viruses threaten tsetse mass production. Here we demonstrated the presence of two single-stranded RNA viruses isolated from Glossina morsitans morsitans originating from a colony at the Seibersdorf rearing facility. The genome organization and the phylogenetic analysis based on the RNA-dependent RNA polymerase (RdRp) revealed that the two viruses belong to the genera Iflavirus and Negevirus, respectively. The names proposed for the two viruses are Glossina morsitans morsitans iflavirus (GmmIV) and Glossina morsitans morsitans negevirus (GmmNegeV). The GmmIV genome is 9685 nucleotides long with a poly(A) tail and encodes a single polyprotein processed into structural and non-structural viral proteins. The GmmNegeV genome consists of 8140 nucleotides and contains two major overlapping open reading frames (ORF1 and ORF2). ORF1 encodes the largest protein which includes a methyltransferase domain, a ribosomal RNA methyltransferase domain, a helicase domain and a RdRp domain. In this study, a selective RT-qPCR assay to detect the presence of the negative RNA strand for both GmmIV and GmmNegeV viruses proved that both viruses replicate in G. m. morsitans. We analyzed the tissue tropism of these viruses in G. m. morsitans by RNA-FISH to decipher their mode of transmission. Our results demonstrate that both viruses can be found not only in the host’s brain and fat bodies but also in their reproductive organs, and in milk and salivary glands. These findings suggest a potential horizontal viral transmission during feeding and/or a vertically viral transmission from parent to offspring. Although the impact of GmmIV and GmmNegeV in tsetse rearing facilities is still unknown, none of the currently infected tsetse species show any signs of disease from these viruses.
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Affiliation(s)
- Irene K. Meki
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria; (I.K.M.); (H.-I.H.); (H.M.K.)
| | - Hannah-Isadora Huditz
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria; (I.K.M.); (H.-I.H.); (H.M.K.)
- Laboratory of Virology, Wageningen University and Research, 6708 PB Wageningen, The Netherlands; (R.A.A.v.d.V.); (J.M.V.); (M.M.v.O.)
| | - Anton Strunov
- Lab Genome Dynamics, Department Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstraße 17, 1090 Vienna, Austria; (A.S.); (W.J.M.)
| | - René A. A. van der Vlugt
- Laboratory of Virology, Wageningen University and Research, 6708 PB Wageningen, The Netherlands; (R.A.A.v.d.V.); (J.M.V.); (M.M.v.O.)
| | - Henry M. Kariithi
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria; (I.K.M.); (H.-I.H.); (H.M.K.)
- Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, USDA-ARS, Athens, GA 30605, USA
- Biotechnology Research Center, Kenya Agricultural and Livestock Research Organization, Nairobi P.O. Box 57811-00200, Kenya
| | - Mohammadreza Rezapanah
- Iranian Research Institute of Plant Protection (IRIPP), Agricultural Research Education and Extension Organization (AREEO), Tehran 19395, Iran;
| | - Wolfgang J. Miller
- Lab Genome Dynamics, Department Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstraße 17, 1090 Vienna, Austria; (A.S.); (W.J.M.)
| | - Just M. Vlak
- Laboratory of Virology, Wageningen University and Research, 6708 PB Wageningen, The Netherlands; (R.A.A.v.d.V.); (J.M.V.); (M.M.v.O.)
| | - Monique M. van Oers
- Laboratory of Virology, Wageningen University and Research, 6708 PB Wageningen, The Netherlands; (R.A.A.v.d.V.); (J.M.V.); (M.M.v.O.)
| | - Adly M. M. Abd-Alla
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria; (I.K.M.); (H.-I.H.); (H.M.K.)
- Correspondence: ; Tel.: +43-12-60-02-84-25
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Lüthi MN, Vorburger C, Dennis AB. A Novel RNA Virus in the Parasitoid Wasp Lysiphlebus fabarum: Genomic Structure, Prevalence, and Transmission. Viruses 2020; 12:E59. [PMID: 31947801 PMCID: PMC7019493 DOI: 10.3390/v12010059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/19/2019] [Accepted: 12/31/2019] [Indexed: 12/30/2022] Open
Abstract
We report on a novel RNA virus infecting the wasp Lysiphlebus fabarum, a parasitoid of aphids. This virus, tentatively named "Lysiphlebus fabarum virus" (LysV), was discovered in transcriptome sequences of wasps from an experimental evolution study in which the parasitoids were allowed to adapt to aphid hosts (Aphis fabae) with or without resistance-conferring endosymbionts. Based on phylogenetic analyses of the viral RNA-dependent RNA polymerase (RdRp), LysV belongs to the Iflaviridae family in the order of the Picornavirales, with the closest known relatives all being parasitoid wasp-infecting viruses. We developed an endpoint PCR and a more sensitive qPCR assay to screen for LysV in field samples and laboratory lines. These screens verified the occurrence of LysV in wild parasitoids and identified the likely wild-source population for lab infections in Western Switzerland. Three viral haplotypes could be distinguished in wild populations, of which two were found in the laboratory. Both vertical and horizontal transmission of LysV were demonstrated experimentally, and repeated sampling of laboratory populations suggests that the virus can form persistent infections without obvious symptoms in infected wasps.
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Affiliation(s)
- Martina N. Lüthi
- Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; (C.V.); (A.B.D.)
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Christoph Vorburger
- Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; (C.V.); (A.B.D.)
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Alice B. Dennis
- Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; (C.V.); (A.B.D.)
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
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