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Hernández-Pelegrín L, Huditz HI, García-Castillo P, de Ruijter NCA, van Oers MM, Herrero S, Ros VID. Covert RNA viruses in medflies differ in their mode of transmission and tissue tropism. J Virol 2024; 98:e0010824. [PMID: 38742874 PMCID: PMC11237731 DOI: 10.1128/jvi.00108-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/12/2024] [Indexed: 05/16/2024] Open
Abstract
Numerous studies have demonstrated the presence of covert viral infections in insects. These infections can be transmitted in insect populations via two main routes: vertical from parents to offspring, or horizontal between nonrelated individuals. Thirteen covert RNA viruses have been described in the Mediterranean fruit fly (medfly). Some of these viruses are established in different laboratory-reared and wild medfly populations, although variations in the viral repertoire and viral levels have been observed at different time points. To better understand these viral dynamics, we characterized the prevalence and levels of covert RNA viruses in two medfly strains, assessed the route of transmission of these viruses, and explored their distribution in medfly adult tissues. Altogether, our results indicated that the different RNA viruses found in medflies vary in their preferred route of transmission. Two iflaviruses and a narnavirus are predominantly transmitted through vertical transmission via the female, while a nodavirus and a nora virus exhibited a preference for horizontal transmission. Overall, our results give valuable insights into the viral tropism and transmission of RNA viruses in the medfly, contributing to the understanding of viral dynamics in insect populations. IMPORTANCE The presence of RNA viruses in insects has been extensively covered. However, the study of host-virus interaction has focused on viruses that cause detrimental effects to the host. In this manuscript, we uncovered which tissues are infected with covert RNA viruses in the agricultural pest Ceratitis capitata, and which is the preferred transmission route of these viruses. Our results showed that vertical and horizontal transmission can occur simultaneously, although each virus is transmitted more efficiently following one of these routes. Additionally, our results indicated an association between the tropism of the RNA virus and the preferred route of transmission. Overall, these results set the basis for understanding how viruses are established and maintained in medfly populations.
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Affiliation(s)
- Luis Hernández-Pelegrín
- Laboratory of Virology, Department of Plant Science, Wageningen University and Research, Wageningen, the Netherlands
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
| | - Hannah-Isadora Huditz
- Laboratory of Virology, Department of Plant Science, Wageningen University and Research, Wageningen, the Netherlands
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, Vienna, Austria
| | - Pablo García-Castillo
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
| | - Norbert C A de Ruijter
- Laboratory of Cell and Developmental Biology, Department of Plant Science, Wageningen University and Research, Wageningen, the Netherlands
| | - Monique M van Oers
- Laboratory of Virology, Department of Plant Science, Wageningen University and Research, Wageningen, the Netherlands
| | - Salvador Herrero
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
| | - Vera I D Ros
- Laboratory of Virology, Department of Plant Science, Wageningen University and Research, Wageningen, the Netherlands
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Kumar Pradhan S, Morrow JL, Sharpe SR, Karuppannasamy A, Ramasamy E, Bynakal S, Maligeppagol M, Ramasamy A, Riegler M. RNA virus diversity and prevalence in field and laboratory populations of melon fly throughout its distribution. J Invertebr Pathol 2024; 204:108117. [PMID: 38679365 DOI: 10.1016/j.jip.2024.108117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 04/17/2024] [Accepted: 04/25/2024] [Indexed: 05/01/2024]
Abstract
Insects have a rich diversity of RNA viruses that can either cause acute infections or persist in host populations without visible symptoms. The melon fly, Zeugodacus cucurbitae (Tephritidae) causes substantial economic losses through infestation of diverse cucurbit and other crops. Of Indomalayan origin, it is now established in many tropical regions of the world. The virome diversity of Z. cucurbitae is largely unknown across large parts of its distribution, including the Indian subcontinent. We have analysed three transcriptomes each of one field-collected and one laboratory-reared Z. cucurbitae population from Bangalore (India) and discovered genomes of ten putative RNA viruses: two sigmaviruses, one chimbavirus, one cripavirus, one noda-like virus, one nora virus, one orbivirus, one partiti-like virus, one sobemovirus and one toti-like virus. Analysis of the only available host genome of a Hawaiian Z. cucurbitae population did not detect host genome integration of the detected viruses. While all ten viruses were found in the Bangalore field population only seven were detected in the laboratory population, indicating that these seven may cause persistent covert infections. Using virus-specific RNA-dependent RNA polymerase gene primers, we detected nine of the RNA viruses with an overall low variant diversity in some but not all individual flies from four out of five Indian regions. We then screened 39 transcriptomes of Z. cucurbitae laboratory populations from eastern Asia (Guangdong, Hainan, Taiwan) and the Pacific region (Hawaii), and detected seven of the ten virus genomes. We found additional genomes of a picorna-like virus and a negev-like virus. Hawaii as the only tested population from the fly's invasive range only had one virus. Our study provides evidence of new and high RNA virus diversity in Indian populations within the original range of Z. cucurbitae, as well as the presence of persistent covert infections in laboratory populations. It builds the basis for future research of tephritid-associated RNA viruses, including their host effects, epidemiology and application potential in biological control.
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Affiliation(s)
- Sanjay Kumar Pradhan
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia; ICAR- Indian Institute of Horticultural Research, Hesaraghatta Lake, Bengaluru 560089, Karnataka, India; Department of Agricultural Entomology, University of Agricultural Sciences, Bengaluru 560065, Karnataka, India.
| | - Jennifer L Morrow
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia.
| | - Stephen R Sharpe
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia.
| | - Ashok Karuppannasamy
- ICAR- Indian Institute of Horticultural Research, Hesaraghatta Lake, Bengaluru 560089, Karnataka, India; Tamil Nadu Agricultural University, Coimbatore 641003, Tamil Nadu, India; Tata Institute for Genetics and Society, Bengaluru 560065, Karnataka, India.
| | - Ellango Ramasamy
- Computational and Mathematical Biology Centre (CMBC), THSTI- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad 121001, Haryana, India.
| | - Shivanna Bynakal
- Department of Agricultural Entomology, University of Agricultural Sciences, Bengaluru 560065, Karnataka, India.
| | - Manamohan Maligeppagol
- ICAR- Indian Institute of Horticultural Research, Hesaraghatta Lake, Bengaluru 560089, Karnataka, India.
| | - Asokan Ramasamy
- ICAR- Indian Institute of Horticultural Research, Hesaraghatta Lake, Bengaluru 560089, Karnataka, India.
| | - Markus Riegler
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia.
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Sharpe SR, Morrow JL, Cook JM, Papanicolaou A, Riegler M. Transmission mode predicts coinfection patterns of insect-specific viruses in field populations of the Queensland fruit fly. Mol Ecol 2024; 33:e17226. [PMID: 38018898 DOI: 10.1111/mec.17226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 10/05/2023] [Accepted: 11/13/2023] [Indexed: 11/30/2023]
Abstract
Insect-specific viruses (ISVs) can affect insect health and fitness, but can also interact with other insect-associated microorganisms. Despite this, ISVs are often studied in isolation from each other, in laboratory populations. Consequently, their diversity, prevalence and associations with other viruses in field populations are less known, yet these parameters are important to understanding virus epidemiology. To help address this knowledge gap, we assessed the diversity, prevalence and coinfections of three ISVs (horizontally transmitted cripavirus, biparentally transmitted sigmavirus and maternally transmitted iflavirus) in 29 field populations of Queensland fruit fly, Australia's most significant horticultural pest, in the context of their different transmission modes. We detected new virus variant diversity. In contrast to the very high virus prevalence in laboratory populations, 46.8% of 293 field flies carried one virus and 4.8% had two viruses. Cripavirus and sigmavirus occurred in all regions, while iflavirus was restricted to subtropical and tropical regions. Cripavirus was most prevalent (37.5%), followed by sigmavirus (13.7%) and iflavirus (4.4%). Cripavirus coinfected some flies with either one of the two vertically transmitted viruses. However, sigmavirus did not coinfect individuals with iflavirus. Three different modelling approaches detected negative association patterns between sigmavirus and iflavirus, consistent with the absence of such coinfections in laboratory populations. This may be linked with their maternal transmission and the ineffective paternal transmission of sigmavirus. Furthermore, we found that, unlike sigmavirus and iflavirus, cripavirus load was higher in laboratory than field flies. Laboratory and mass-rearing conditions may increase ISV prevalence and load due to increased transmission opportunities. We conclude that a combination of field and laboratory studies is needed to uncover ISV interactions and further our understanding of ISV epidemiology.
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Affiliation(s)
- Stephen R Sharpe
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | - Jennifer L Morrow
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | - James M Cook
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | - Alexie Papanicolaou
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | - Markus Riegler
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
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Karlin DG. WIV, a protein domain found in a wide number of arthropod viruses, which probably facilitates infection. J Gen Virol 2024; 105. [PMID: 38193819 DOI: 10.1099/jgv.0.001948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024] Open
Abstract
The most powerful approach to detect distant homologues of a protein is based on structure prediction and comparison. Yet this approach is still inapplicable to many viral proteins. Therefore, we applied a powerful sequence-based procedure to identify distant homologues of viral proteins. It relies on three principles: (1) traces of sequence similarity can persist beyond the significance cutoff of homology detection programmes; (2) candidate homologues can be identified among proteins with weak sequence similarity to the query by using 'contextual' information, e.g. taxonomy or type of host infected; (3) these candidate homologues can be validated using highly sensitive profile-profile comparison. As a test case, this approach was applied to a protein without known homologues, encoded by ORF4 of Lake Sinai viruses (which infect bees). We discovered that the ORF4 protein contains a domain that has homologues in proteins from >20 taxa of viruses infecting arthropods. We called this domain 'widespread, intriguing, versatile' (WIV), because it is found in proteins with a wide variety of functions and within varied domain contexts. For example, WIV is found in the NSs protein of tospoviruses, a global threat to food security, which infect plants as well as their arthropod vectors; in the RNA2 ORF1-encoded protein of chronic bee paralysis virus, a widespread virus of bees; and in various proteins of cypoviruses, which infect the silkworm Bombyx mori. Structural modelling with AlphaFold indicated that the WIV domain has a previously unknown fold, and bibliographical evidence suggests that it facilitates infection of arthropods.
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Affiliation(s)
- David G Karlin
- Division Phytomedicine, Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-Universität zu Berlin, Lentzeallee 55/57, D-14195 Berlin, Germany
- Independent Researcher, Marseille, France
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5
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Hernández-Pelegrín L, Ros VID, Herrero S, Crava CM. Non-retroviral Endogenous Viral Elements in Tephritid Fruit Flies Reveal Former Viral Infections Not Related to Known Circulating Viruses. MICROBIAL ECOLOGY 2023; 87:7. [PMID: 38036897 PMCID: PMC10689555 DOI: 10.1007/s00248-023-02310-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 10/19/2023] [Indexed: 12/02/2023]
Abstract
A wide variety of insect-specific non-retroviral RNA viruses specifically infect insects. During viral infection, fragments of viral sequences can integrate into the host genomes creating non-retroviral endogenous viral elements (nrEVEs). Although the exact function of nrEVEs is so far unknown, some studies suggest that nrEVEs may interfere with virus replication by producing PIWI-interacting RNAs (piRNAs) that recognize and degrade viral RNAs through sequence complementarity. In this article, we identified the nrEVEs repertoire of ten species within the dipteran family Tephritidae (true fruit flies), which are considered a major threat to agriculture worldwide. Our results suggest that each of these species contains nrEVEs, although in limited numbers, and that nrEVE integration may have occurred both before and after speciation. Furthermore, the majority of nrEVEs originated from viruses with negative single-stranded RNA genomes and represent structural viral functions. Notably, these nrEVEs exhibit low similarity to currently known circulating viruses. To explore the potential role of nrEVEs, we investigated their transcription pattern and the production of piRNAs in different tissues of Ceratitis capitata. We successfully identified piRNAs that are complementary to the sequence of one nrEVE in C. capitata, thereby highlighting a potential link between nrEVEs and the piRNA pathway. Overall, our results provide valuable insights into the comparative landscape of nrEVEs in true fruit flies, contributing to the understanding of the intimate relation between fruit flies and their past and present viral pathogens.
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Affiliation(s)
- Luis Hernández-Pelegrín
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Dr Moliner 50, 46100, Burjassot (Valencia), Spain
| | - Vera I D Ros
- Laboratory of Virology, Wageningen University and Research, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
| | - Salvador Herrero
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Dr Moliner 50, 46100, Burjassot (Valencia), Spain
| | - Cristina M Crava
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Dr Moliner 50, 46100, Burjassot (Valencia), Spain.
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Qi YH, Ye ZX, Zhang CX, Chen JP, Li JM. Diversity of RNA viruses in agricultural insects. Comput Struct Biotechnol J 2023; 21:4312-4321. [PMID: 37711182 PMCID: PMC10497914 DOI: 10.1016/j.csbj.2023.08.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 09/16/2023] Open
Abstract
Recent advancements in next-generation sequencing (NGS) technology and bioinformatics tools have revealed a vast array of viral diversity in insects, particularly RNA viruses. However, our current understanding of insect RNA viruses has primarily focused on hematophagous insects due to their medical importance, while research on the viromes of agriculturally relevant insects remains limited. This comprehensive review aims to address the gap by providing an overview of the diversity of RNA viruses in agricultural pests and beneficial insects within the agricultural ecosystem. Based on the NCBI Virus Database, over eight hundred RNA viruses belonging to 39 viral families have been reported in more than three hundred agricultural insect species. These viruses are predominantly found in the insect orders of Hymenoptera, Hemiptera, Thysanoptera, Lepidoptera, Diptera, Coleoptera, and Orthoptera. These findings have significantly enriched our understanding of RNA viral diversity in agricultural insects. While further virome investigations are necessary to expand our knowledge to more insect species, it is crucial to explore the biological roles of these identified RNA viruses within insects in future studies. This review also highlights the limitations and challenges for the effective virus discovery through NGS and their potential solutions, which might facilitate for the development of innovative bioinformatic tools in the future.
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Affiliation(s)
- Yu-Hua Qi
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Zhuang-Xin Ye
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Chuan-Xi Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Jian-Ping Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Jun-Min Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
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7
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Morrow JL, Sharpe SR, Tilden G, Wyatt P, Oczkowicz S, Riegler M. Transmission modes and efficiency of iflavirus and cripavirus in Queensland fruit fly, Bactrocera tryoni. J Invertebr Pathol 2023; 197:107874. [PMID: 36574813 DOI: 10.1016/j.jip.2022.107874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 12/13/2022] [Accepted: 12/21/2022] [Indexed: 12/25/2022]
Abstract
Infections of insects with insect-specific RNA viruses are common and can affect host fitness and health. Previously, persistent RNA virus infections were detected in tephritid fruit flies, including the Queensland fruit fly (Bactrocera tryoni), Australia's most significant horticultural pest. Their transmission modes and efficiency are unclear yet may influence virus epidemiology in field and laboratory populations. Using standard RT-PCR and RT-qPCR we detected iflavirus, cripavirus and sigmavirus in five laboratory populations recently established with field-collected B.tryoni. Virus absence in some individuals suggested that virus transmission is incomplete. Random virus segregation in an isofemale experiment resulted in the establishment of isofemale lines with and without iflavirus and cripavirus. In infected lines, viral loads normalised against host gene transcripts were variable, but did not differ between pupae and adults. Iflavirus and cripavirus were transmitted horizontally, with viruses detected (including at low viral loads) in many previously uninfected individuals after four days, and in most after 12 days cohabitation with infected flies. Iflavirus, but not cripavirus, was transmitted vertically, and surface-sterilised embryos contained high loads. Furthermore, high iflavirus loads in individual females resulted in high loads in their offspring. We demonstrated that viruses are highly prevalent in laboratory populations and that it is possible to establish and maintain uninfected fly lines for the assessment of virus transmission and host effects. This is important for pest management strategies such as the sterile insect technique which requires the mass-rearing of flies, as their fitness and performance may be affected by covert virus infections.
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Affiliation(s)
- Jennifer L Morrow
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia.
| | - Stephen R Sharpe
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Geraldine Tilden
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Pauline Wyatt
- Department of Agriculture and Fisheries Queensland, Ecosciences Precinct, 41 Boggo Road, Dutton Park, QLD 4102, Australia
| | - Sybilla Oczkowicz
- Department of Agriculture and Fisheries Queensland, Redden Street Research Facility, 21-23 Redden Street, Portsmith, QLD 4870, Australia
| | - Markus Riegler
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia.
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