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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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Popa-Báez ÁD, Lee SF, Yeap HL, Westmore G, Crisp P, Li D, Catullo R, Cameron EC, Edwards OR, Taylor PW, Oakeshott JG. Tracing the origins of recent Queensland fruit fly incursions into South Australia, Tasmania and New Zealand. Biol Invasions 2021. [DOI: 10.1007/s10530-020-02422-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Climate stress resistance in male Queensland fruit fly varies among populations of diverse geographic origins and changes during domestication. BMC Genet 2020; 21:135. [PMID: 33339509 PMCID: PMC7747409 DOI: 10.1186/s12863-020-00935-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Background The highly polyphagous Queensland fruit fly (Bactrocera tryoni Froggatt) expanded its range substantially during the twentieth century and is now the most economically important insect pest of Australian horticulture, prompting intensive efforts to develop a Sterile Insect Technique (SIT) control program. Using a “common garden” approach, we have screened for natural genetic variation in key environmental fitness traits among populations from across the geographic range of this species and monitored changes in those traits induced during domestication. Results Significant variation was detected between the populations for heat, desiccation and starvation resistance and wing length (as a measure of body size). Desiccation resistance was correlated with both starvation resistance and wing length. Bioassay data for three resampled populations indicate that much of the variation in desiccation resistance reflects persistent, inherited differences among the populations. No latitudinal cline was detected for any of the traits and only weak correlations were found with climatic variables for heat resistance and wing length. All three stress resistance phenotypes and wing length changed significantly in certain populations with ongoing domestication but there was also a strong population by domestication interaction effect for each trait. Conclusions Ecotypic variation in heat, starvation and desiccation resistance was detected in Australian Qfly populations, and these stress resistances diminished rapidly during domestication. Our results indicate a need to select source populations for SIT strains which have relatively high climatic stress resistance and to minimise loss of that resistance during domestication.
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Tayler A, Heschuk D, Giesbrecht D, Park JY, Whyard S. Efficiency of RNA interference is improved by knockdown of dsRNA nucleases in tephritid fruit flies. Open Biol 2019; 9:190198. [PMID: 31795920 PMCID: PMC6936256 DOI: 10.1098/rsob.190198] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/30/2019] [Indexed: 12/22/2022] Open
Abstract
RNA interference (RNAi) in insects is routinely used to ascertain gene function, but also has potential as a technology to control pest species. For some insects, such as beetles, ingestion of small quantities of double-stranded RNA (dsRNA) is able to knock down a targeted gene's expression. However, in other species, ingestion of dsRNA can be ineffective owing to the presence of nucleases within the gut, which degrade dsRNA before it reaches target cells. In this study, we observed that nucleases within the gut of the Queensland fruit fly (Bactrocera tryoni) rapidly degrade dsRNA and reduce RNAi efficacy. By complexing dsRNA with liposomes within the adult insect's diet, RNAi-mediated knockdown of a melanin synthesis gene, yellow, was improved significantly, resulting in strong RNAi phenotypes. RNAi efficiency was also enhanced by feeding both larvae and adults for several days on dsRNAs that targeted two different dsRNase gene transcripts. Co-delivery of both dsRNase-specific dsRNAs and yellow dsRNA resulted in almost complete knockdown of the yellow transcripts. These findings show that the use of liposomes or co-feeding of nuclease-specific dsRNAs significantly improves RNAi inhibition of gene expression in B. tryoni and could be a useful strategy to improve RNAi-based control in other insect species.
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Affiliation(s)
| | | | | | | | - Steve Whyard
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, CanadaR3T 2N2
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Raphael KA, Sved JA, Pearce S, Oakeshott JG, Gilchrist AS, Sherwin WB, Frommer M. Differences in gene regulation in a tephritid model of prezygotic reproductive isolation. INSECT MOLECULAR BIOLOGY 2019; 28:689-702. [PMID: 30955213 DOI: 10.1111/imb.12583] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The two tephritid fruit fly pests, Bactrocera tryoni and Bactrocera neohumeralis, are unusually well suited to the study of the genetics of reproductive isolating mechanisms. Sequence difference between the species is no greater than between a pair of conspecific Drosophila melanogaster populations. The two species exist in close sympatry, yet do not hybridize in the field, apparently kept separate by a strong premating isolation mechanism involving the time of day at which mating occurs. This spurred us to search for key genes for which time of day expression is regulated differently between the species. Using replicated, quantitative transcriptomes from head tissues of males of the two species, sampled in the day and night, we identified 141 transcripts whose abundance showed a significant interaction between species and time of day, indicating a difference in gene regulation. The brain transcripts showing this interaction were enriched for genes with a neurone function and 90% of these were more abundant at night than day in B. tryoni. Features of the expression patterns suggest that there may be a difference in the regulation of sleep-wake cycles between the species. In particular several genes, which in D. melanogaster are expressed in circadian pacemaker cells, are promising candidates to further explore the genetic differentiation involved in this prezygotic reproductive isolation mechanism.
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Affiliation(s)
- K A Raphael
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - J A Sved
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - S Pearce
- CSIRO Land & Water Flagship, Canberra, ACT, Australia
| | - J G Oakeshott
- CSIRO Land & Water Flagship, Canberra, ACT, Australia
| | - A S Gilchrist
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - W B Sherwin
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - M Frommer
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia
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Blacket MJ, Malipatil MB, Semeraro L, Gillespie PS, Dominiak BC. Screening mitochondrial DNA sequence variation as an alternative method for tracking established and outbreak populations of Queensland fruit fly at the species southern range limit. Ecol Evol 2017; 7:2604-2616. [PMID: 28428851 PMCID: PMC5395428 DOI: 10.1002/ece3.2783] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/29/2016] [Accepted: 01/11/2017] [Indexed: 12/03/2022] Open
Abstract
Understanding the relationship between incursions of insect pests and established populations is critical to implementing effective control. Studies of genetic variation can provide powerful tools to examine potential invasion pathways and longevity of individual pest outbreaks. The major fruit fly pest in eastern Australia, Queensland fruit fly Bactrocera tryoni (Froggatt), has been subject to significant long‐term quarantine and population reduction control measures in the major horticulture production areas of southeastern Australia, at the species southern range limit. Previous studies have employed microsatellite markers to estimate gene flow between populations across this region. In this study, we used an independent genetic marker, mitochondrial DNA (mtDNA) sequences, to screen genetic variation in established and adjacent outbreak populations in southeastern Australia. During the study period, favorable environmental conditions resulted in multiple outbreaks, which appeared genetically distinctive and relatively geographically localized, implying minimal dispersal between simultaneous outbreaks. Populations in established regions were found to occur over much larger areas. Screening mtDNA (female) lineages proved to be an effective alternative genetic tool to assist in understanding fruit fly population dynamics and provide another possible molecular method that could now be employed for better understanding of the ecology and evolution of this and other pest species.
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Affiliation(s)
- Mark J Blacket
- Agriculture Victoria AgriBio, Centre for AgriBioscience Bundoora Victoria 3083 Australia
| | - Mali B Malipatil
- Agriculture Victoria AgriBio, Centre for AgriBioscience Bundoora Victoria 3083 Australia.,School of Applied Systems Biology La Trobe University Bundoora Victoria 3083 Australia
| | - Linda Semeraro
- Agriculture Victoria AgriBio, Centre for AgriBioscience Bundoora Victoria 3083 Australia
| | - Peter S Gillespie
- Agricultural Scientific Collections Unit Department of Primary Industries New South Wales Orange Agricultural Institute Orange NSW Australia
| | - Bernie C Dominiak
- Department of Primary Industries New South Wales Orange NSW Australia
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The application of “-omics” technologies for the classification and identification of animals. ORG DIVERS EVOL 2015. [DOI: 10.1007/s13127-015-0234-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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