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Wulff JP, Hickner PV, Watson DW, Denning SS, Belikoff EJ, Scott MJ. Antennal transcriptome analysis reveals sensory receptors potentially associated with host detection in the livestock pest Lucilia cuprina. Parasit Vectors 2024; 17:308. [PMID: 39026238 PMCID: PMC11256703 DOI: 10.1186/s13071-024-06391-6] [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: 05/09/2024] [Accepted: 07/03/2024] [Indexed: 07/20/2024] Open
Abstract
BACKGROUND Lucilia cuprina (Wiedemann, 1830) (Diptera: Calliphoridae) is the main causative agent of flystrike of sheep in Australia and New Zealand. Female flies lay eggs in an open wound or natural orifice, and the developing larvae eat the host's tissues, a condition called myiasis. To improve our understanding of host-seeking behavior, we quantified gene expression in male and female antennae based on their behavior. METHODS A spatial olfactometer was used to evaluate the olfactory response of L. cuprina mated males and gravid females to fresh or rotting beef. Antennal RNA-Seq analysis was used to identify sensory receptors differentially expressed between groups. RESULTS Lucilia cuprina females were more attracted to rotten compared to fresh beef (> fivefold increase). However, males and some females did not respond to either type of beef. RNA-Seq analysis was performed on antennae dissected from attracted females, non-attracted females and males. Transcripts encoding sensory receptors from 11 gene families were identified above a threshold (≥ 5 transcript per million) including 49 ATP-binding cassette transporters (ABCs), two ammonium transporters (AMTs), 37 odorant receptors (ORs), 16 ionotropic receptors (IRs), 5 gustatory receptors (GRs), 22 odorant-binding proteins (OBPs), 9 CD36-sensory neuron membrane proteins (CD36/SNMPs), 4 chemosensory proteins (CSPs), 4 myeloid lipid-recognition (ML) and Niemann-Pick C2 disease proteins (ML/NPC2), 2 pickpocket receptors (PPKs) and 3 transient receptor potential channels (TRPs). Differential expression analyses identified sex-biased sensory receptors. CONCLUSIONS We identified sensory receptors that were differentially expressed between the antennae of both sexes and hence may be associated with host detection by female flies. The most promising for future investigations were as follows: an odorant receptor (LcupOR46) which is female-biased in L. cuprina and Cochliomyia hominivorax Coquerel, 1858; an ABC transporter (ABC G23.1) that was the sole sensory receptor upregulated in the antennae of females attracted to rotting beef compared to non-attracted females; a female-biased ammonia transporter (AMT_Rh50), which was previously associated with ammonium detection in Drosophila melanogaster Meigen, 1830. This is the first report suggesting a possible role for ABC transporters in L. cuprina olfaction and potentially in other insects.
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Affiliation(s)
- Juan P Wulff
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Paul V Hickner
- United States Department of Agriculture, Agricultural Research Service, Knipling-Bushland U.S. Livestock Insects Research Laboratory, 2700 Fredericksburg Road, Kerrville, TX, 78028-9184, USA
| | - David W Watson
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Steven S Denning
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Esther J Belikoff
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA.
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Yan Y, Hosseini B, Scheld A, Pasham S, Rehling T, Schetelig MF. Effects of antibiotics on the in vitro expression of tetracycline-off constructs and the performance of Drosophila suzukii female-killing strains. Front Bioeng Biotechnol 2023; 11:876492. [PMID: 36865029 PMCID: PMC9971817 DOI: 10.3389/fbioe.2023.876492] [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: 02/15/2022] [Accepted: 01/26/2023] [Indexed: 02/16/2023] Open
Abstract
Genetic control strategies such as the Release of Insects Carrying a Dominant Lethal (RIDL) gene and Transgenic Embryonic Sexing System (TESS) have been demonstrated in the laboratory and/or deployed in the field. These strategies are based on tetracycline-off (Tet-off) systems which are regulated by antibiotics such as Tet and doxycycline (Dox). Here, we generated several Tet-off constructs carrying a reporter gene cassette mediated by a 2A peptide. Different concentrations (0.1, 10, 100, 500, and 1,000 μg/mL) and types (Tet or Dox) of antibiotics were used to evaluate their effects on the expression of the Tet-off constructs in the Drosophila S2 cells. One or both of the two concentrations, 100 and 250 μg/mL, of Tet or Dox were used to check the influence on the performances of a Drosophila suzukii wild-type strain and female-killing (FK) strains employing TESS. Specifically, the Tet-off construct for these FK strains contains a Drosophila suzukii nullo promoter to regulate the tetracycline transactivator gene and a sex-specifically spliced pro-apoptotic gene hid Ala4 to eliminate females. The results suggested that the in vitro expression of the Tet-off constructs was controlled by antibiotics in a dose-dependent manner. ELISA experiments were carried out identifying Tet at 34.8 ng/g in adult females that fed on food supplemented with Tet at 100 μg/mL. However, such method did not detect Tet in the eggs produced by antibiotic-treated flies. Additionally, feeding Tet to the parents showed negative impact on the fly development but not the survival in the next generation. Importantly, we demonstrated that under certain antibiotic treatments females could survive in the FK strains with different transgene activities. For the strain V229_M4f1 which showed moderate transgene activity, feeding Dox to fathers or mothers suppressed the female lethality in the next generation and feeding Tet or Dox to mothers generated long-lived female survivors. For the strain V229_M8f2 which showed weak transgene activity, feeding Tet to mothers delayed the female lethality for one generation. Therefore, for genetic control strategies employing the Tet-off system, the parental and transgenerational effects of antibiotics on the engineered lethality and insect fitness must be carefully evaluated for a safe and efficient control program.
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Affiliation(s)
- Ying Yan
- Department of Insect Biotechnology in Plant Protection, Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany,*Correspondence: Ying Yan,
| | - Bashir Hosseini
- Department of Insect Biotechnology in Plant Protection, Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Annemarie Scheld
- Department of Insect Biotechnology in Plant Protection, Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Srilakshmi Pasham
- Department of Insect Biotechnology in Plant Protection, Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Tanja Rehling
- Department of Insect Biotechnology in Plant Protection, Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Marc F. Schetelig
- Department of Insect Biotechnology in Plant Protection, Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany,Liebig Centre for Agroecology and Climate Impact Research, Justus-Liebig-University Giessen, Giessen, Germany
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3
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Upadhyay A, Feltman NR, Sychla A, Janzen A, Das SR, Maselko M, Smanski M. Genetically engineered insects with sex-selection and genetic incompatibility enable population suppression. eLife 2022; 11:71230. [PMID: 35108195 PMCID: PMC8860436 DOI: 10.7554/elife.71230] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 01/31/2022] [Indexed: 11/18/2022] Open
Abstract
Engineered Genetic Incompatibility (EGI) is a method to create species-like barriers to sexual reproduction. It has applications in pest control that mimic Sterile Insect Technique when only EGI males are released. This can be facilitated by introducing conditional female-lethality to EGI strains to generate a sex-sorting incompatible male system (SSIMS). Here, we demonstrate a proof of concept by combining tetracycline-controlled female lethality constructs with a pyramus-targeting EGI line in the model insect Drosophila melanogaster. We show that both functions (incompatibility and sex-sorting) are robustly maintained in the SSIMS line and that this approach is effective for population suppression in cage experiments. Further we show that SSIMS males remain competitive with wild-type males for reproduction with wild-type females, including at the level of sperm competition.
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Affiliation(s)
- Ambuj Upadhyay
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States
| | - Nathan R Feltman
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Saint Paul, United States
| | - Adam Sychla
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Saint Paul, United States
| | - Anna Janzen
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Saint Paul, United States
| | - Siba R Das
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Saint Paul, United States
| | | | - Michael Smanski
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Saint Paul, United States
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4
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Kotze AC, James PJ. Control of sheep flystrike: what's been tried in the past and where to from here. Aust Vet J 2021; 100:1-19. [PMID: 34761372 PMCID: PMC9299489 DOI: 10.1111/avj.13131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 10/04/2021] [Accepted: 10/17/2021] [Indexed: 12/01/2022]
Abstract
Flystrike remains a serious financial and animal welfare issue for the sheep industry in Australia despite many years of research into control methods. The present paper provides an extensive review of past research on flystrike, and highlights areas that hold promise for providing long-term control options. We describe areas where the application of modern scientific advances may provide increased impetus to some novel, as well as some previously explored, control methods. We provide recommendations for research activities: insecticide resistance management, novel delivery methods for therapeutics, improved breeding indices for flystrike-related traits, mechanism of nematode-induced scouring in mature animals. We also identify areas where advances can be made in flystrike control through the greater adoption of well-recognised existing management approaches: optimal insecticide-use patterns, increased use of flystrike-related Australian Sheep Breeding Values, and management practices to prevent scouring in young sheep. We indicate that breeding efforts should be primarily focussed on the adoption and improvement of currently available breeding tools and towards the future integration of genomic selection methods. We describe factors that will impact on the ongoing availability of insecticides for flystrike control and on the feasibility of vaccination. We also describe areas where the blowfly genome may be useful in providing impetus to some flystrike control strategies, such as area-wide approaches that seek to directly suppress or eradicate sheep blowfly populations. However, we also highlight the fact that commercial and feasibility considerations will act to temper the potential for the genome to act as the basis for providing some control options.
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Affiliation(s)
- A C Kotze
- CSIRO Agriculture and Food, St Lucia, Queensland, 4067, Australia
| | - P J James
- QAAFI, University of Queensland, St Lucia, Queensland, 4067, Australia
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5
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Conditional knockdown of transformer in sheep blow fly suggests a role in repression of dosage compensation and potential for population suppression. PLoS Genet 2021; 17:e1009792. [PMID: 34662332 PMCID: PMC8553175 DOI: 10.1371/journal.pgen.1009792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 10/28/2021] [Accepted: 08/24/2021] [Indexed: 11/19/2022] Open
Abstract
The transformer (tra) gene is essential for female development in many insect species, including the Australian sheep blow fly, Lucilia cuprina. Sex-specific tra RNA splicing is controlled by Sex lethal (Sxl) in Drosophila melanogaster but is auto-regulated in L. cuprina. Sxl also represses X chromosome dosage compensation in female D. melanogaster. We have developed conditional Lctra RNAi knockdown strains using the tet-off system. Four strains did not produce females on diet without tetracycline and could potentially be used for genetic control of L. cuprina. In one strain, which showed both maternal and zygotic tTA expression, most XX transformed males died at the pupal stage. RNAseq and qRT-PCR analyses of mid-stage pupae showed increased expression of X-linked genes in XX individuals. These results suggest that Lctra promotes somatic sexual differentiation and inhibits X chromosome dosage compensation in female L. cuprina. However, XX flies homozygous for a loss-of-function Lctra knockin mutation were fully transformed and showed high pupal eclosion. Two of five X-linked genes examined showed a significant increase in mRNA levels in XX males. The stronger phenotype in the RNAi knockdown strain could indicate that maternal Lctra expression may be essential for initiation of dosage compensation suppression in female embryos.
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6
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Davis RJ, Belikoff EJ, Dickey AN, Scholl EH, Benoit JB, Scott MJ. Genome and transcriptome sequencing of the green bottle fly, Lucilia sericata, reveals underlying factors of sheep flystrike and maggot debridement therapy. Genomics 2021; 113:3978-3988. [PMID: 34619342 DOI: 10.1016/j.ygeno.2021.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/03/2021] [Accepted: 10/01/2021] [Indexed: 12/13/2022]
Abstract
The common green bottle blow fly Lucilia sericata (family, Calliphoridae) is widely used for maggot debridement therapy, which involves the application of sterile maggots to wounds. The larval excretions and secretions are important for consuming necrotic tissue and inhibiting bacterial growth in wounds of patients. Lucilia sericata is also of importance as a pest of sheep and in forensic studies to estimate a postmortem interval. Here we report the assembly of a 565.3 Mb genome from long read PacBio DNA sequencing of genomic DNA. The genome contains 14,704 predicted protein coding genes and 1709 non-coding genes. Targeted annotation and transcriptional analyses identified genes that are highly expressed in the larval salivary glands (secretions) and Malpighian tubules (excretions) under normal growth conditions and following heat stress. The genomic resources will underpin future genetic studies and in development of engineered strains for genetic control of L. sericata and for biotechnology-enhanced maggot therapy.
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Affiliation(s)
- Rebecca J Davis
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA.
| | - Esther J Belikoff
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA.
| | - Allison N Dickey
- Bioinformatics Research Center, North Carolina State University, Campus Box 7566, Raleigh, NC 27695-7566, USA.
| | - Elizabeth H Scholl
- Bioinformatics Research Center, North Carolina State University, Campus Box 7566, Raleigh, NC 27695-7566, USA.
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45211, USA.
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA.
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7
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The β 2Tubulin, Rad50-ATPase and enolase cis-regulatory regions mediate male germline expression in Tribolium castaneum. Sci Rep 2021; 11:18131. [PMID: 34518617 PMCID: PMC8438054 DOI: 10.1038/s41598-021-97443-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/19/2021] [Indexed: 11/19/2022] Open
Abstract
Genetics-based pest management processes, including the sterile insect technique, are an effective method for the control of some pest insects. However, current SIT methods are not directly transferable to many important pest insect species due to the lack of genetic sexing strains. Genome editing is revolutionizing the way we conduct genetics in insects, including in Tribolium castaneum, an important genetic model and agricultural pest. We identified orthologues of β2Tubulin, Rad50-ATPase and enolase in T. castaneum. Using RT-PCR, we confirmed that these genes are predominantly expressed in the testis. PiggyBac-based transformation of T. castaneum cis-regulatory regions derived from Tc-β2t, Tc-rad50 or Tc-eno resulted in EGFP expression specifically in the T. castaneum testis. Additionally, we determined that each of these regulatory regions regulates EGFP expression in different cell types of the male gonad. Cis-regulatory regions from Tc-β2t produced EGFP expression throughout spermatogenesis and also in mature sperms; Tc-rad50 resulted in expression only in the haploid spermatid, while Tc-eno expressed EGFP in late spermatogenesis. In summary, the regulatory cis-regions characterized in this study are not only suited to study male gonadal function but could be used for development of transgenic sexing strains that produce one sex in pest control strategies.
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8
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Schetelig MF, Schwirz J, Yan Y. A transgenic female killing system for the genetic control of Drosophila suzukii. Sci Rep 2021; 11:12938. [PMID: 34155227 PMCID: PMC8217240 DOI: 10.1038/s41598-021-91938-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/02/2021] [Indexed: 02/05/2023] Open
Abstract
The spotted wing Drosophila (Drosophila suzukii) is an invasive pest of soft-skinned fruit crops. It is rapidly transmitted in Europe and North America, causing widespread agricultural losses. Genetic control strategies such as the sterile insect technique (SIT) have been proposed as environment-friendly and species-restricted approaches for this pest. However, females are inefficient agents in SIT programs. Here we report a conditional female-killing (FK) strategy based on the tetracycline-off system. We assembled sixteen genetic constructs for testing in vitro and in vivo. Twenty-four independent transgenic strains of D. suzukii were generated and tested for female-specific lethality. The strongest FK effect in the absence of tetracycline was achieved by the construct containing D. suzukii nullo promoter for early gene expression, D. suzukii pro-apoptotic gene hidAla4 for lethality, and the transformer gene intron from the Mediterranean fruit fly Ceratitis capitata for female-specific splicing. One strain carrying this construct eliminated 100% of the female offspring during embryogenesis and produced only males. However, homozygous females from these FK strains were not viable on a tetracycline-supplemented diet, possibly due to the basal expression of hidAla4. Potential improvements to the gene constructs and the use of such FK strains in an SIT program are discussed.
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Affiliation(s)
- Marc F Schetelig
- Institute for Insect Biotechnology, Department of Insect Biotechnology in Plant Protection, Justus-Liebig-University Giessen, Winchesterstraße 2, 35394, Giessen, Germany
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Winchesterstraße 2, 35394, Giessen, Germany
| | - Jonas Schwirz
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Winchesterstraße 2, 35394, Giessen, Germany
| | - Ying Yan
- Institute for Insect Biotechnology, Department of Insect Biotechnology in Plant Protection, Justus-Liebig-University Giessen, Winchesterstraße 2, 35394, Giessen, Germany.
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Winchesterstraße 2, 35394, Giessen, Germany.
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9
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Vella MR, Gould F, Lloyd AL. Mathematical modeling of genetic pest management through female-specific lethality: Is one locus better than two? Evol Appl 2021; 14:1612-1622. [PMID: 34178107 PMCID: PMC8210802 DOI: 10.1111/eva.13228] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 01/03/2023] Open
Abstract
Many novel genetic approaches are under development to combat insect pests. One genetic strategy aims to suppress or locally eliminate a species through large, repeated releases of genetically engineered strains that render female offspring unviable under field conditions. Strains with this female-killing characteristic have been developed either with all of the molecular components in a single construct or with the components in two constructs inserted at independently assorting loci. Strains with two constructs are typically considered to be only of value as research tools and for producing solely male offspring in rearing factories which are subsequently sterilized by radiation before release. A concern with the two-construct strains is that once released, the two constructs would become separated and therefore non-functional. The only female-killing strains that have been released in the field without sterilization are single-construct strains. Here, we use a population genetics model with density dependence to evaluate the relative effectiveness of female-killing approaches based on single- and two-construct arrangements. We find that, in general, the single-construct arrangement results in slightly faster population suppression, but the two-construct arrangement can eventually cause stronger suppression and cause local elimination with a smaller release size. Based on our results, there is no a priori reason that males carrying two independently segregating constructs need to be sterilized prior to release. In some cases, a fertile release would be more efficient for population suppression.
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Affiliation(s)
- Michael R. Vella
- Biomathematics Graduate ProgramNorth Carolina State UniversityRaleighNorth CarolinaUSA
- Genetic Engineering and Society CenterNorth Carolina State UniversityRaleighNorth CarolinaUSA
| | - Fred Gould
- Genetic Engineering and Society CenterNorth Carolina State UniversityRaleighNorth CarolinaUSA
- Department of Entomology and Plant PathologyNorth Carolina State UniversityRaleighNorth CarolinaUSA
| | - Alun L. Lloyd
- Biomathematics Graduate ProgramNorth Carolina State UniversityRaleighNorth CarolinaUSA
- Genetic Engineering and Society CenterNorth Carolina State UniversityRaleighNorth CarolinaUSA
- Department of MathematicsNorth Carolina State UniversityRaleighNorth CarolinaUSA
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10
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Nguyen TNM, Choo A, Baxter SW. Lessons from Drosophila: Engineering Genetic Sexing Strains with Temperature-Sensitive Lethality for Sterile Insect Technique Applications. INSECTS 2021; 12:243. [PMID: 33805657 PMCID: PMC8001749 DOI: 10.3390/insects12030243] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/05/2021] [Accepted: 03/09/2021] [Indexed: 12/29/2022]
Abstract
A major obstacle of sterile insect technique (SIT) programs is the availability of robust sex-separation systems for conditional removal of females. Sterilized male-only releases improve SIT efficiency and cost-effectiveness for agricultural pests, whereas it is critical to remove female disease-vector pests prior to release as they maintain the capacity to transmit disease. Some of the most successful Genetic Sexing Strains (GSS) reared and released for SIT control were developed for Mediterranean fruit fly (Medfly), Ceratitis capitata, and carry a temperature sensitive lethal (tsl) mutation that eliminates female but not male embryos when heat treated. The Medfly tsl mutation was generated by random mutagenesis and the genetic mechanism causing this valuable heat sensitive phenotype remains unknown. Conditional temperature sensitive lethal mutations have also been developed using random mutagenesis in the insect model, Drosophila melanogaster, and were used for some of the founding genetic research published in the fields of neuro- and developmental biology. Here we review mutations in select D. melanogaster genes shibire, Notch, RNA polymerase II 215kDa, pale, transformer-2, Dsor1 and CK2α that cause temperature sensitive phenotypes. Precise introduction of orthologous point mutations in pest insect species with CRISPR/Cas9 genome editing technology holds potential to establish GSSs with embryonic lethality to improve and advance SIT pest control.
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Affiliation(s)
- Thu N. M. Nguyen
- Bio21 Institute, School of BioSciences, University of Melbourne, Melbourne, VIC 3052, Australia;
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia;
| | - Amanda Choo
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia;
| | - Simon W. Baxter
- Bio21 Institute, School of BioSciences, University of Melbourne, Melbourne, VIC 3052, Australia;
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11
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Ahmed HMM, Heese F, Wimmer EA. Improvement on the genetic engineering of an invasive agricultural pest insect, the cherry vinegar fly, Drosophila suzukii. BMC Genet 2020; 21:139. [PMID: 33339511 PMCID: PMC7747376 DOI: 10.1186/s12863-020-00940-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Background The invasive fly Drosophila suzukii has become an established fruit pest in Europe, the USA, and South America with no effective and safe pest management. Genetic engineering enables the development of transgene-based novel genetic control strategies against insect pests and disease vectors. This, however, requires the establishment of reliable germline transformation techniques. Previous studies have shown that D. suzukii is amenable to transgenesis using the transposon-based vectors piggyBac and Minos, site-specific recombination (lox/Cre), and CRISPR/Cas9 genome editing. Results We experienced differences in the usability of piggyBac-based germline transformation in different strains of D. suzukii: we obtained no transgenic lines in a US strain, a single rare transgenic line in an Italian strain, but observed a reliable transformation rate of 2.5 to 11% in a strain from the French Alps. This difference in efficiency was confirmed by comparative examination of these three strains. In addition, we used an attP landing site line to successfully established φC31-integrase-mediated plasmid integration at a rate of 10% and generated landing site lines with two attP sequences to effectively perform φC31-Recombinase Mediated Cassette Exchange (φC31-RMCE) with 11% efficiency. Moreover, we isolated and used the endogenous regulatory regions of Ds nanos to express φC31 integrase maternally to generate self-docking lines for φC31-RMCE. Besides, we isolated the promoter/enhancer of Ds serendipity α to drive the heterologous tetracycline-controlled transactivator (tTA) during early embryonic development and generated a testes-specific tTA driver line using the endogenous beta-2-tubulin (β2t) promoter/enhancer. Conclusion Our results provide evidence that the D. suzukii strain AM derived from the French Alps is more suitable for piggyBac germline transformation than other strains. We demonstrated the feasibility of using φC31-RMCE in the cherry vinegar fly and generated a set of lines that can be used for highly efficient integration of larger constructs. The φC31-based integration will facilitate modification and stabilization of previously generated transgenic lines that carry at least one attP site in the transgene construction. An early embryo-specific and a spermatogenesis-specific driver line were generated for future use of the binary expression system tet-off to engineer tissue- and stage-specific effector gene expression for genetic pest control strategies. Supplementary Information The online version contains supplementary material available at 10.1186/s12863-020-00940-5.
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Affiliation(s)
- Hassan M M Ahmed
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077, Göttingen, Germany.,Department of Crop Protection, Faculty of Agriculture-University of Khartoum, P.O. Box 32, 13314, Khartoum North, Khartoum, Sudan
| | - Fabienne Heese
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077, Göttingen, Germany
| | - Ernst A Wimmer
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077, Göttingen, Germany.
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12
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Yan Y, Scott MJ. Building a transgenic sexing strain for genetic control of the Australian sheep blow fly Lucilia cuprina using two lethal effectors. BMC Genet 2020; 21:141. [PMID: 33339506 PMCID: PMC8348823 DOI: 10.1186/s12863-020-00947-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background The sterile insect technique (SIT) has been
successfully used in many pest management programs worldwide.
Some SIT programs release both sexes due to the lack of genetic
sexing strains or efficient sex separation methods but sterile
females are ineffective control agents. Transgenic sexing
strains (TSS) using the tetracycline-off control system have
been developed in a variety of insect pests, from which females
die by either of two commonly used lethal effectors:
overexpression of the transcription factor tetracycline transactivator (tTA)
or ectopic expression of a proapoptotic gene, such as head involution defective
(hid). The lethality from
tTA overexpression is thought to be due to “transcriptional
squelching”, while hid causes
lethality by induction of apoptosis. This study aims to create
and characterize a TSS of Lucilia
cuprina, which is a major pest of sheep, by
combining both lethal effectors in a single transgenic
strain. Results Here a stable TSS of L.
cuprina (DH6) that carries two lethal effectors
was successfully generated, by crossing FL3#2 which carries a
female-specific tTA overexpression cassette, with EF1#12 which
carries a tTA-regulated LshidAla2 cassette. Females with
one copy of the FL3#2 transgene are viable but up to 99.8% of
homozygous females die at the pupal stage when raised on diet
that lacks tetracycline. Additionally, the female lethality of
FL3#2 was partially repressed by supplying tetracycline to the
parental generation. With an additional LshidAla2 effector, the female
lethality of DH6 is 100% dominant and cannot be repressed by
maternal tetracycline. DH6 females die at the late-larval stage.
Several fitness parameters important for mass rearing such as
hatching rate, adult emergence and sex ratio were comparable to
those of the wild type strain. Conclusions Compared to the parental FL3#2 strain, the DH6
strain shows stronger female lethality and lethality occurs at
an earlier stage of development. The combination of two
tTA-dependent lethal effectors could improve strain stability
under mass rearing and could reduce the risk of resistance in
the field if fertile males are released. Our approach could be
easily adapted for other pest species for an efficient, safe and
sustainable genetic control program. Supplementary Information The online version contains supplementary material available
at 10.1186/s12863-020-00947-y.
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Affiliation(s)
- Ying Yan
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.,Department of Insect Biotechnology in Plant Protection, Justus-Liebig-University Giessen, Institute for Insect Biotechnology, Winchesterstraße 2, 35394, Giessen, Germany
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.
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13
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Yan Y, Jaffri SA, Schwirz J, Stein C, Schetelig MF. Identification and characterization of four Drosophila suzukii cellularization genes and their promoters. BMC Genet 2020; 21:146. [PMID: 33339500 PMCID: PMC7747377 DOI: 10.1186/s12863-020-00939-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background The spotted-wing Drosophila (Drosophila suzukii) is a widespread invasive pest that causes severe economic damage to fruit crops. The early development of D. suzukii is similar to that of other Drosophilids, but the roles of individual genes must be confirmed experimentally. Cellularization genes coordinate the onset of cell division as soon as the invagination of membranes starts around the nuclei in the syncytial blastoderm. The promoters of these genes have been used in genetic pest-control systems to express transgenes that confer embryonic lethality. Such systems could be helpful in sterile insect technique applications to ensure that sterility (bi-sex embryonic lethality) or sexing (female-specific embryonic lethality) can be achieved during mass rearing. The activity of cellularization gene promoters during embryogenesis controls the timing and dose of the lethal gene product. Results Here, we report the isolation of the D. suzukii cellularization genes nullo, serendipity-α, bottleneck and slow-as-molasses from a laboratory strain. Conserved motifs were identified by comparing the encoded proteins with orthologs from other Drosophilids. Expression profiling confirmed that all four are zygotic genes that are strongly expressed at the early blastoderm stage. The 5′ flanking regions from these cellularization genes were isolated, incorporated into piggyBac vectors and compared in vitro for the promoter activities. The Dsnullo promoter showed the highest activity in the cell culture assays using D. melanogaster S2 cells. Conclusions The similarities in the gene coding and 5′ flanking sequence as well as in the expression pattern of the four cellularization genes between D. melanogaster and D. suzukii, suggest that conserved functions may be involved in both species. The high expression level at the early blastoderm stage of the four cellularization genes were confirmed, thus their promoters can be considered in embryonic lethality systems. While the Dsnullo promoter could be a suitable candidate, all reported promoters here are subject to further in vivo analyses before constructing potential pest control systems. Supplementary Information The online version contains supplementary material available at 10.1186/s12863-020-00939-y.
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Affiliation(s)
- Ying Yan
- Justus-Liebig-University Giessen, Institute for Insect Biotechnology, Department of Insect Biotechnology in Plant Protection, Winchesterstr. 2, 35394, Giessen, Germany. .,Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 35394, Giessen, Germany.
| | - Syeda A Jaffri
- Justus-Liebig-University Giessen, Institute for Insect Biotechnology, Department of Insect Biotechnology in Plant Protection, Winchesterstr. 2, 35394, Giessen, Germany
| | - Jonas Schwirz
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 35394, Giessen, Germany
| | - Carl Stein
- Justus-Liebig-University Giessen, Institute for Insect Biotechnology, Department of Insect Biotechnology in Plant Protection, Winchesterstr. 2, 35394, Giessen, Germany
| | - Marc F Schetelig
- Justus-Liebig-University Giessen, Institute for Insect Biotechnology, Department of Insect Biotechnology in Plant Protection, Winchesterstr. 2, 35394, Giessen, Germany. .,Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 35394, Giessen, Germany.
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14
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Concha C, Yan Y, Arp A, Quilarque E, Sagel A, de León AP, McMillan WO, Skoda S, Scott MJ. An early female lethal system of the New World screwworm, Cochliomyia hominivorax, for biotechnology-enhanced SIT. BMC Genet 2020; 21:143. [PMID: 33339501 PMCID: PMC7747452 DOI: 10.1186/s12863-020-00948-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The New World Screwworm fly (NWS), Cochliomyia hominivorax, is an ectoparasite of warm-blooded animals and a major pest of livestock in parts of South America and the Caribbean where it remains endemic. In North and Central America it was eradicated using the Sterile Insect Technique (SIT). A control program is managed cooperatively between the governments of the United States and Panama to prevent the northward spread of NWS from infested countries in South America. This is accomplished by maintaining a permanent barrier through the release of millions of sterile male and female flies in the border between Panama and Colombia. Our research team demonstrated the utility of biotechnology-enhanced approaches for SIT by developing a male-only strain of the NWS. The strain carried a single component tetracycline repressible female lethal system where females died at late larval/pupal stages. The control program can be further improved by removing females during embryonic development as larval diet costs are significant. RESULTS The strains developed carry a two-component system consisting of the Lucilia sericata bottleneck gene promoter driving expression of the tTA gene and a tTA-regulated Lshid proapoptotic effector gene. Insertion of the sex-specifically spliced intron from the C. hominivorax transformer gene within the Lshid gene ensures that only females die when insects are reared in the absence of tetracycline. In several double homozygous two-component strains and in one "All-in-one" strain that had both components in a single construct, female lethality occurred at the embryonic and/or first instar larval stages when raised on diet without tetracycline. Laboratory evaluation for phenotypes that are relevant for mass rearing in a production facility revealed that most strains had fitness characteristics similar to the wild type J06 strain that is currently reared for release in the permanent barrier. Testing of an "All in one" strain under mass rearing conditions showed that the strain maintained the fitness characteristics observed in small-scale rearing. CONCLUSIONS The early female lethal strains described here could be selected by the NWS Control Program for testing at large scale in the production facility to enhance the efficiency of the NWS eradication program.
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Affiliation(s)
- Carolina Concha
- Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG), Pacora, Panama. .,Smithsonian Tropical Research Institute, Apartado 0843-03092, Panama City, Panama.
| | - Ying Yan
- Department for Insect Biotechnology in Plant Protection, Justus-Liebig-University Gießen, Winchesterstraße 2, 35394, Gießen, Germany
| | - Alex Arp
- USDA-ARS, Screwworm Research Site, Apartado 0816-07636, Pacora, Panama.,Knipling-Bushland U.S. Livestock Insects Research Laboratory, 2700 Fredericksburg Rd, Kerrville, TX, 78028, USA
| | - Evelin Quilarque
- USDA-ARS, Screwworm Research Site, Apartado 0816-07636, Pacora, Panama
| | - Agustin Sagel
- USDA-ARS, Screwworm Research Site, Apartado 0816-07636, Pacora, Panama
| | - Adalberto Pérez de León
- Knipling-Bushland U.S. Livestock Insects Research Laboratory, 2700 Fredericksburg Rd, Kerrville, TX, 78028, USA
| | - W Owen McMillan
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Panama City, Panama
| | - Steven Skoda
- USDA-ARS, Screwworm Research Site, Apartado 0816-07636, Pacora, Panama.,Knipling-Bushland U.S. Livestock Insects Research Laboratory, 2700 Fredericksburg Rd, Kerrville, TX, 78028, USA
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.
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15
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Using Moderate Transgene Expression to Improve the Genetic Sexing System of the Australian Sheep Blow Fly Lucilia cuprina. INSECTS 2020; 11:insects11110797. [PMID: 33202756 PMCID: PMC7697711 DOI: 10.3390/insects11110797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 11/24/2022]
Abstract
Simple Summary Populations of pest insects can be suppressed through repeated mass releases of sterilized insects. This is particularly effective if only sterile males are released. We previously developed several genetically modified strains of the Australian sheep blowfly that produce only males when raised on diet that lacked tetracycline. A disadvantage of the some of the engineered strains was that females would lay few eggs unless fed a diet with a low dose of tetracycline. In this study we show that effective male-only strains can be made by combining driver/effector lines that have moderate transgene expression/activity. Furthermore, the strain does not require tetracycline in the adult diet for female fertility. This “moderate expression/activity” strategy could be more generally applied to other pests that can be genetically modified. Abstract The sterile insect technique (SIT) is a promising strategy to control the Australian sheep blow fly Lucilia cuprina, a major pest of sheep. We have previously developed a transgenic embryonic sexing system (TESS) for this pest to facilitate the potential SIT application. TESS carry two transgenes, a tetracycline transactivator (tTA) driver and a tTA-activated pro-apoptotic effector. TESS females die at the embryonic stage unless tetracycline is supplied in the diet. However, undesired female sterility was observed in some TESS strains without tetracycline due to expression of tTA in ovaries. Here we investigate if TESS that combine transgenes with relatively low/moderate expression/activity improves the fertility of TESS females. tTA driver lines were evaluated for tTA expression by quantitative real time PCR and/or by crossing with a tTA-activated RFPex effector line. Fertility and lethality tests showed that a TESS strain containing a driver line with moderate tTA expression and an effector line showing moderate pro-apoptotic activity could recover the fertility of parental females and eliminated all female offspring at the embryonic stage. Consequently, such a strain could be further evaluated for an SIT program for L. cuprina, and such a “moderate strategy” could be considered for the TESS development in other pest species.
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16
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Scott MJ, Benoit JB, Davis RJ, Bailey ST, Varga V, Martinson EO, Hickner PV, Syed Z, Cardoso GA, Torres TT, Weirauch MT, Scholl EH, Phillippy AM, Sagel A, Vasquez M, Quintero G, Skoda SR. Genomic analyses of a livestock pest, the New World screwworm, find potential targets for genetic control programs. Commun Biol 2020; 3:424. [PMID: 32753684 PMCID: PMC7403345 DOI: 10.1038/s42003-020-01152-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 07/14/2020] [Indexed: 12/13/2022] Open
Abstract
The New World Screwworm fly, Cochliomyia hominivorax, is a major pest of livestock in South America and Caribbean. However, few genomic resources have been available for this species. A genome of 534 Mb was assembled from long read PacBio DNA sequencing of DNA from a highly inbred strain. Analysis of molecular evolution identified 40 genes that are likely under positive selection. Developmental RNA-seq analysis identified specific genes associated with each stage. We identify and analyze the expression of genes that are likely important for host-seeking behavior (chemosensory), development of larvae in open wounds in warm-blooded animals (heat shock protein, immune response) and for building transgenic strains for genetic control programs including gene drive (sex determination, germline). This study will underpin future experiments aimed at understanding the parasitic lifestyle of the screwworm fly and greatly facilitate future development of strains for efficient systems for genetic control of screwworm.
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Affiliation(s)
- Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, McMicken School of Arts and Sciences, Cincinnati, OH, 45221, USA
| | - Rebecca J Davis
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA
| | - Samuel T Bailey
- Department of Biological Sciences, University of Cincinnati, McMicken School of Arts and Sciences, Cincinnati, OH, 45221, USA
| | - Virag Varga
- Department of Biological Sciences, University of Cincinnati, McMicken School of Arts and Sciences, Cincinnati, OH, 45221, USA
| | - Ellen O Martinson
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Paul V Hickner
- Department of Entomology, University of Kentucky, Lexington, KY, 40546, USA
| | | | - Gisele A Cardoso
- Department of Genetics and Evolutionary Biology, University of São Paulo, São Paulo, Brazil
| | - Tatiana T Torres
- Department of Genetics and Evolutionary Biology, University of São Paulo, São Paulo, Brazil
| | - Matthew T Weirauch
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
- Divisions of Biomedical Informatics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Elizabeth H Scholl
- Bioinformatics Research Center, North Carolina State University, Campus Box 7566, Raleigh, NC, 27695-7566, USA
| | - Adam M Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD, 20892, USA
| | | | | | | | - Steven R Skoda
- USDA-ARS, Tick and Biting Fly Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA
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17
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Schwirz J, Yan Y, Franta Z, Schetelig MF. Bicistronic expression and differential localization of proteins in insect cells and Drosophila suzukii using picornaviral 2A peptides. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 119:103324. [PMID: 31978587 DOI: 10.1016/j.ibmb.2020.103324] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/14/2020] [Accepted: 01/14/2020] [Indexed: 06/10/2023]
Abstract
Polycistronic expression systems in insects can be used for applications such as recombinant protein production in cells, enhanced transgenesis methods, and the development of novel pest-control strategies based on the sterile insect technique (SIT). Here we tested the performance of four picornaviral 2A self-cleaving peptides (TaV-2A, DrosCV-2A, FMDV 2A1/31 and FMDV 2A1/32) for the co-expression and differential subcellular targeting of two fluorescent marker proteins in cell lines (Anastrepha suspensa AsE01 and Drosophila melanogaster S2 cells). We found that all four 2A peptides showed comparable activity in cell lines, leading to the production of independent upstream and downstream proteins that were directed to the nucleus or membrane by a C-terminal nuclear localization signal (NLS) on the upstream protein and a poly-lysine/CAAX membrane anchor on the downstream protein. TaV-2A and DrosCV-2A were inserted into piggyBac constructs to create transgenic D. suzukii strains, confirming efficient ribosomal skipping in vivo. Interestingly, we found that the EGFP-CAAX protein was distributed homogeneously in the membrane whereas the DsRed-CAAX protein formed clumps and aggregates that induced extensive membrane blebbing. Accordingly, only flies expressing the DsRed-NLS and EGFP-CAAX proteins could be bred to homozygosity whereas expression of EGFP-NLS and DsRed-CAAX was lethal in the homozygous state. Our results therefore demonstrate that the 2A constructs and two novel targeting motifs are functional in D. suzukii, and that the combination of EGFP-NLS and DsRed-CAAX shows dosage-dependent lethality. These molecular elements could be further used to improve expression systems in insects and generate novel pest control strains.
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Affiliation(s)
- Jonas Schwirz
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Winchesterstraße 2, Germany; Microscopy Core Facility, Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, Mainz, Germany
| | - Ying Yan
- Justus-Liebig-University Gießen, Department for Insect Biotechnology in Plant Protection, Winchesterstraße 2, 35394, Gießen, Germany.
| | - Zdenek Franta
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Winchesterstraße 2, Germany
| | - Marc F Schetelig
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Winchesterstraße 2, Germany; Justus-Liebig-University Gießen, Department for Insect Biotechnology in Plant Protection, Winchesterstraße 2, 35394, Gießen, Germany.
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18
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Ahmed HMM, Hildebrand L, Wimmer EA. Improvement and use of CRISPR/Cas9 to engineer a sperm-marking strain for the invasive fruit pest Drosophila suzukii. BMC Biotechnol 2019; 19:85. [PMID: 31805916 PMCID: PMC6896403 DOI: 10.1186/s12896-019-0588-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 11/26/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The invasive fruit pest Drosophila suzukii was reported for the first time in Europe and the USA in 2008 and has spread since then. The adoption of type II clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) as a tool for genome manipulation provides new ways to develop novel biotechnologically-based pest control approaches. Stage or tissue-specifically expressed genes are of particular importance in the field of insect biotechnology. The enhancer/promoter of the spermatogenesis-specific beta-2-tubulin (β2t) gene was used to drive the expression of fluorescent proteins or effector molecules in testes of agricultural pests and disease vectors for sexing, monitoring, and reproductive biology studies. Here, we demonstrate an improvement to CRISPR/Cas-based genome editing in D. suzukii and establish a sperm-marking system. RESULTS To improve genome editing, we isolated and tested the D. suzukii endogenous promoters of the small nuclear RNA gene U6 to drive the expression of a guide RNA and the Ds heat shock protein 70 promoter to express Cas9. For comparison, we used recombinant Cas9 protein and in vitro transcribed gRNA as a preformed ribonucleoprotein. We demonstrate the homology-dependent repair (HDR)-based genome editing efficiency by applying a previously established transgenic line that expresses DsRed ubiquitously as a target platform. In addition, we isolated the Ds_β2t gene and used its promoter to drive the expression of a red fluorescence protein in the sperm. A transgenic sperm-marking strain was then established by the improved HDR-based genome editing. CONCLUSION The deployment of the endogenous promoters of the D. suzukii U6 and hsp70 genes to drive the expression of gRNA and Cas9, respectively, enabled the effective application of helper plasmid co-injections instead of preformed ribonucleoproteins used in previous reports for HDR-based genome editing. The sperm-marking system should help to monitor the success of pest control campaigns in the context of the Sterile Insect Technique and provides a tool for basic research in reproductive biology of this invasive pest. Furthermore, the promoter of the β2t gene can be used in developing novel transgenic pest control approaches and the CRISPR/Cas9 system as an additional tool for the modification of previously established transgenes.
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Affiliation(s)
- Hassan M M Ahmed
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077, Göttingen, Germany
- Department of Crop Protection, Faculty of Agriculture-University of Khartoum, P.O. Box 32, 13314, Khartoum, Khartoum North, Sudan
| | - Luisa Hildebrand
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077, Göttingen, Germany
| | - Ernst A Wimmer
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, 37077, Göttingen, Germany.
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19
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Yan Y, Williamson ME, Davis RJ, Andere AA, Picard CJ, Scott MJ. Improved transgenic sexing strains for genetic control of the Australian sheep blow fly Lucilia cuprina using embryo-specific gene promoters. Mol Genet Genomics 2019; 295:287-298. [PMID: 31720776 DOI: 10.1007/s00438-019-01622-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 11/04/2019] [Indexed: 10/25/2022]
Abstract
For genetic approaches for controlling insect pests such as the sterile insect technique (SIT), it is advantageous to release only males as females are ineffective as control agents and they consume about 50% of the diet. Here we developed tetracycline-repressible Lucilia cuprina transgenic strains in which adult females were fully fertile and viable on a diet that lacked tetracycline and all of their female offspring died at the embryo stage. The transgenic strains are an improvement over the strains we developed previously, which had the disadvantage that adult females on diet without tetracycline were sterile and died prematurely. This was possibly due to the low level expression of the effector gene in ovaries. In the strains developed in this study, the early promoters from L. cuprina nullo or Cochliomyia macellaria CG14427 genes were used to drive the tetracycline transactivator (tTA) expression in the early embryo. In the absence of tetracycline, tTA activates expression of the proapoptotic gene Lshid which contains a female-specific intron. Consequently, only females produce active HID protein and die at the embryo stage. Crossing the tTA-expressing driver lines with an RFPex reporter line confirmed that there was no expression of the effector gene in the ovary. These new embryonic L. cuprina transgenic sexing strains hold great promise for genetic control programs and the system reported here might also be transferable to other major calliphorid livestock pests such as the New World screwworm, Cochliomyia hominivorax.
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Affiliation(s)
- Ying Yan
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.,Fraunhofer IME-BR, Winchesterstr. 2, 35394, Giessen, Germany
| | - Megan E Williamson
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA
| | - Rebecca J Davis
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA
| | - Anne A Andere
- Fraunhofer IME-BR, Winchesterstr. 2, 35394, Giessen, Germany
| | - Christine J Picard
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, 46202, USA
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.
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20
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Paulo DF, Williamson ME, Arp AP, Li F, Sagel A, Skoda SR, Sanchez-Gallego J, Vasquez M, Quintero G, Pérez de León AA, Belikoff EJ, Azeredo-Espin AML, McMillan WO, Concha C, Scott MJ. Specific Gene Disruption in the Major Livestock Pests Cochliomyia hominivorax and Lucilia cuprina Using CRISPR/Cas9. G3 (BETHESDA, MD.) 2019; 9:3045-3055. [PMID: 31340950 PMCID: PMC6723136 DOI: 10.1534/g3.119.400544] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 07/23/2019] [Indexed: 02/07/2023]
Abstract
Cochliomyia hominivorax and Lucilia cuprina are major pests of livestock. Their larvae infest warm-blooded vertebrates and feed on host's tissues, resulting in severe industry losses. As they are serious pests, considerable effort has been made to develop genomic resources and functional tools aiming to improve their management and control. Here, we report a significant addition to the pool of genome manipulation tools through the establishment of efficient CRISPR/Cas9 protocols for the generation of directed and inheritable modifications in the genome of these flies. Site-directed mutations were introduced in the C hominivorax and L cuprina yellow genes (ChY and LcY) producing lightly pigmented adults. High rates of somatic mosaicism were induced when embryos were injected with Cas9 ribonucleoprotein complexes (RNPs) pre-assembled with guide RNAs (sgRNAs) at high concentrations. Adult flies carrying disrupted yellow alleles lacked normal pigmentation (brown body phenotype) and efficiently transmitted the mutated alleles to the subsequent generation, allowing the rapid creation of homozygous strains for reverse genetics of candidate loci. We next used our established CRISPR protocol to disrupt the C hominivorax transformer gene (Chtra). Surviving females carrying mutations in the Chtra locus developed mosaic phenotypes of transformed ovipositors with characteristics of male genitalia while exhibiting abnormal reproductive tissues. The CRISPR protocol described here is a significant improvement on the existing toolkit of molecular methods in calliphorids. Our results also suggest that Cas9-based systems targeting Chtra and Lctra could be an effective means for controlling natural populations of these important pests.
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Affiliation(s)
- Daniel F Paulo
- Centre for Molecular Biology and Genetic Engineering, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas
- Laboratory of Ecological and Evolutionary Genomics, Smithsonian Tropical Research Institute, Gamboa, Panama
| | - Megan E Williamson
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh NC
| | - Alex P Arp
- USDA-ARS, Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, Kerrville TX, and
| | - Fang Li
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh NC
| | - Agustin Sagel
- USDA-ARS, Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, Screwworm Research Site, Pacora, Panama
| | - Steven R Skoda
- USDA-ARS, Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, Screwworm Research Site, Pacora, Panama
| | - Joel Sanchez-Gallego
- USDA-ARS, Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, Screwworm Research Site, Pacora, Panama
| | - Mario Vasquez
- USDA-ARS, Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, Screwworm Research Site, Pacora, Panama
| | - Gladys Quintero
- USDA-ARS, Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, Screwworm Research Site, Pacora, Panama
| | - Adalberto A Pérez de León
- USDA-ARS, Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, Kerrville TX, and
| | - Esther J Belikoff
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh NC
| | - Ana M L Azeredo-Espin
- Centre for Molecular Biology and Genetic Engineering, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas
| | - W Owen McMillan
- Laboratory of Ecological and Evolutionary Genomics, Smithsonian Tropical Research Institute, Gamboa, Panama
| | - Carolina Concha
- Laboratory of Ecological and Evolutionary Genomics, Smithsonian Tropical Research Institute, Gamboa, Panama
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh NC
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21
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Lutrat C, Giesbrecht D, Marois E, Whyard S, Baldet T, Bouyer J. Sex Sorting for Pest Control: It's Raining Men! Trends Parasitol 2019; 35:649-662. [PMID: 31255488 DOI: 10.1016/j.pt.2019.06.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 05/30/2019] [Accepted: 06/01/2019] [Indexed: 12/16/2022]
Abstract
In the pursuit of better pest- and vector-control strategies, attention returns to an old proven technology, the sterile insect technique (SIT) and related insect population-suppression methods. A major obstacle for any of these approaches that involves the release of sterile males is the separation of males from females during the mass rearing stage, in order to improve the cost-efficiency of these methods and to prevent the release of biting and disease-vectoring females. This review describes recent sex-sorting developments in dipteran flies with an emphasis on assessing the suitability of these methods for large-scale rearing of male vectors for mass release.
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Affiliation(s)
- Célia Lutrat
- CIRAD, UMR ASTRE, F-34398, Montpellier, France; ASTRE, CIRAD, INRA, Univ Montpellier, Montpellier, France; Université de Montpellier, Montpellier, France
| | - David Giesbrecht
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Eric Marois
- CNRS UPR9022, INSERM U963, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Steve Whyard
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Thierry Baldet
- CIRAD, UMR ASTRE, F-34398, Montpellier, France; ASTRE, CIRAD, INRA, Univ Montpellier, Montpellier, France
| | - Jérémy Bouyer
- CIRAD, UMR ASTRE, F-34398, Montpellier, France; Insect Pest Control, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency (IAEA), Vienna, Austria. @cirad.fr
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Abstract
Vector control programs based on population reduction by matings with mass-released sterile insects require the release of only male mosquitoes, as the release of females, even if sterile, would increase the number of biting and potentially disease-transmitting individuals. While small-scale releases demonstrated the applicability of sterile males releases to control the yellow fever mosquito Aedes aegypti, large-scale programs for mosquitoes are currently prevented by the lack of efficient sexing systems in any of the vector species.Different approaches of sexing are pursued, including classical genetic and mechanical methods of sex separation. Another strategy is the development of transgenic sexing systems. Such systems already exist in other insect pests. Genome modification tools could be used to apply similar strategies to mosquitoes. Three major tools to modify mosquito genomes are currently used: transposable elements, site-specific recombination systems, and genome editing via TALEN or CRISPR/Cas. All three can serve the purpose of developing sexing systems and vector control strains in mosquitoes in two ways: first, via their use in basic research. A better understanding of mosquito biology, including the sex-determining pathways and the involved genes can greatly facilitate the development of sexing strains. Moreover, basic research can help to identify other regulatory elements and genes potentially useful for the construction of transgenic sexing systems. Second, these genome modification tools can be used to apply the gained knowledge to build and test mosquito sexing strains for vector control.
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Affiliation(s)
- Irina Häcker
- Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
| | - Marc F Schetelig
- Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany
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Aumann RA, Schetelig MF, Häcker I. Highly efficient genome editing by homology-directed repair using Cas9 protein in Ceratitis capitata. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 101:85-93. [PMID: 30157456 DOI: 10.1016/j.ibmb.2018.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 08/21/2018] [Accepted: 08/24/2018] [Indexed: 06/08/2023]
Abstract
The Mediterranean fruit fly Ceratitis capitata is a highly polyphagous and invasive insect pest, causing enormous economic damage in horticultural systems. A successful and environment-friendly control strategy is the sterile insect technique (SIT) that reduces pest populations through infertile matings with mass-released, sterilized insects. However, the SIT is not readily applicable to each pest species. While transgenic approaches hold great promise to improve critical aspects of the SIT to transfer it to new species, they are suspect to strict or even prohibitive legislation regarding the release of genetically modified (GM) organisms. In contrast, specific mutations created via CRISPR-Cas genome editing are not regulated as GM in the US, and might thus allow creating optimal strains for SIT. Here, we describe highly efficient homology-directed repair genome editing in C. capitata by injecting pre-assembled CRISPR-Cas9 ribonucleoprotein complexes using different guide RNAs and a short single-stranded oligodeoxynucleotide donor to convert an enhanced green fluorescent protein in C. capitata into a blue fluorescent protein. Six out of seven fertile and individually backcrossed G0 individuals generated 57-90% knock-in rate within their total offspring and 70-96% knock-in rate within their phenotypically mutant offspring. Based on the achieved efficiency, this approach could also be used to introduce mutations which do not produce a screenable phenotype and identify positive mutants with a reasonable workload. Furthermore, CRISPR-Cas HDR would allow to recreate mutations formerly identified in classical mutagenesis screens and to transfer them to related species to establish new (SIT-like) pest control systems. Considering the potential that CRISPR-induced alterations in organisms could be classified as non-GM in additional countries, such new strains could potentially be used for pest control applications without the need to struggle with GMO directives.
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Affiliation(s)
- Roswitha A Aumann
- Justus-Liebig-University Gießen, Institute for Insect Biotechnology, Department of Insect Biotechnology in Plant Protection, Winchesterstr. 2, 35394 Gießen, Germany
| | - Marc F Schetelig
- Justus-Liebig-University Gießen, Institute for Insect Biotechnology, Department of Insect Biotechnology in Plant Protection, Winchesterstr. 2, 35394 Gießen, Germany; Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Division of Bioresources, Department of Insect Pest and Vector Control, 35394 Gießen, Germany.
| | - Irina Häcker
- Justus-Liebig-University Gießen, Institute for Insect Biotechnology, Department of Insect Biotechnology in Plant Protection, Winchesterstr. 2, 35394 Gießen, Germany; Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Division of Bioresources, Department of Insect Pest and Vector Control, 35394 Gießen, Germany
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Davis RJ, Belikoff EJ, Scholl EH, Li F, Scott MJ. no blokes Is Essential for Male Viability and X Chromosome Gene Expression in the Australian Sheep Blowfly. Curr Biol 2018; 28:1987-1992.e3. [PMID: 29887311 DOI: 10.1016/j.cub.2018.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/19/2018] [Accepted: 05/02/2018] [Indexed: 12/30/2022]
Abstract
It has been hypothesized that the Drosophila 4th chromosome is derived from an ancient X chromosome [1]. In the Australian sheep blowfly, Lucilia cuprina, the heterochromatic X chromosome contains few active genes and orthologs of Drosophila X-linked genes are autosomal. Of 8 X-linked genes identified previously in L. cuprina, 6 were orthologs of Drosophila 4th-chromosome genes [2]. The X-linked genes were expressed equally in males and females. Here we identify an additional 51 X-linked genes and show that most are dosage compensated. Orthologs of 49 of the 59 X-linked genes are on the 4th chromosome in D. melanogaster. Because painting of fourth (Pof) is important for expression of Drosophila 4th-chromosome genes [3], we used Cas9 to make a loss-of-function knockin mutation in an L. cuprina Pof ortholog we call no blokes (nbl). Homozygous nbl males derived from homozygous nbl mothers die at the late pupal stage. Homozygous nbl females are viable, fertile, and live longer than heterozygous nbl females. RNA expression of most X-linked genes was reduced in homozygous nbl male pupae and to a lesser extent in nbl females compared to heterozygous siblings. The results suggest that NBL could be important for X chromosome dosage compensation in L. cuprina. NBL may also facilitate gene expression in the heterochromatic environment of the X chromosome in both sexes. This study supports the hypothesis on the origin of the Drosophila 4th chromosome and that a POF-like protein was required for normal gene expression on the ancient X chromosome.
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Affiliation(s)
- Rebecca J Davis
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA
| | - Esther J Belikoff
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA
| | - Elizabeth H Scholl
- Bioinformatics Research Center, North Carolina State University, Campus Box 7566, Raleigh, NC 27695-7566, USA
| | - Fang Li
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA.
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Building early-larval sexing systems for genetic control of the Australian sheep blow fly Lucilia cuprina using two constitutive promoters. Sci Rep 2017; 7:2538. [PMID: 28566730 PMCID: PMC5451413 DOI: 10.1038/s41598-017-02763-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 04/18/2017] [Indexed: 11/15/2022] Open
Abstract
Transgenic sexing strains (TSS) that carry conditional female lethal genes are advantageous for genetic control programs based on the sterile insect technique (SIT). It is desirable if females die early in development as larval diet is a major cost for mass production facilities. This can be achieved by using a gene promoter that is only active in embryos to drive expression of the tetracycline transactivator (tTA), the transcription factor commonly used in two-component TSS. While an embryo-specific promoter is ideal it may not be essential for assembling an effective TSS as tTA can be repressed by addition of tetracycline to the diet at larval and/or adult stages. Here we have investigated this idea by isolating and employing the promoters from the Lucilia spitting image and actin 5C genes to drive tTA expression in embryos and later stages. L. cuprina TSS with the tTA drivers and tTA-regulated tetO-Lshid effectors produced only females when raised on a limited tetracycline diet. The Lshid transgene contains a sex-specific intron and as a consequence only females produce LsHID protein. TSS females died at early larval stages, which makes the lines advantageous for an SIT program.
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Harvey-Samuel T, Ant T, Alphey L. Towards the genetic control of invasive species. Biol Invasions 2017; 19:1683-1703. [PMID: 28620268 PMCID: PMC5446844 DOI: 10.1007/s10530-017-1384-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 02/11/2017] [Indexed: 11/13/2022]
Abstract
Invasive species remain one of the greatest threats to global biodiversity. Their control would be enhanced through the development of more effective and sustainable pest management strategies. Recently, a novel form of genetic pest management (GPM) has been developed in which the mating behaviour of insect pests is exploited to introduce genetically engineered DNA sequences into wild conspecific populations. These 'transgenes' work in one or more ways to reduce the damage caused by a particular pest, for example reducing its density, or its ability to vector disease. Although currently being developed for use against economically important insect pests, these technologies would be highly appropriate for application against invasive species that threaten biodiversity. Importantly, these technologies have begun to advance in scope beyond insects to vertebrates, which include some of the world's worst invasives. Here we review the current state of this rapidly progressing field and, using an established set of eradication criteria, discuss the characteristics which make GPM technologies suitable for application against invasive pests.
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27
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Anstead CA, Batterham P, Korhonen PK, Young ND, Hall RS, Bowles VM, Richards S, Scott MJ, Gasser RB. A blow to the fly — Lucilia cuprina draft genome and transcriptome to support advances in biology and biotechnology. Biotechnol Adv 2016; 34:605-620. [DOI: 10.1016/j.biotechadv.2016.02.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 02/08/2016] [Accepted: 02/20/2016] [Indexed: 02/07/2023]
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Concha C, Palavesam A, Guerrero FD, Sagel A, Li F, Osborne JA, Hernandez Y, Pardo T, Quintero G, Vasquez M, Keller GP, Phillips PL, Welch JB, McMillan WO, Skoda SR, Scott MJ. A transgenic male-only strain of the New World screwworm for an improved control program using the sterile insect technique. BMC Biol 2016; 14:72. [PMID: 27576512 PMCID: PMC5004303 DOI: 10.1186/s12915-016-0296-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/10/2016] [Indexed: 11/17/2022] Open
Abstract
Background The New World screwworm, Cochliomyia hominivorax, is a devastating pest of livestock endemic to subtropical and tropical regions of the Western hemisphere. The larvae of this species feed on the tissue of living animals, including man, and can cause death if untreated. Over 60 years ago, the sterile insect technique (SIT) was developed with the aim of eradicating this pest, initially from Florida but subsequently from all of North and Central America. From the outset it was appreciated that SIT would be more efficient if only sterile males were released in the field, but this was not possible until now. Results Here, we report on the development and evaluation of the first sexing strains of C. hominivorax that produce only males when raised on diet without tetracycline. Transgenic lines have been developed that possess a tetracycline repressible female-lethal genetic system. Ten of these lines show high female lethality at the late larval/pupal stages and three of them present dominant female lethality. Most of the lines were comparable to the wild type parental strain in several fitness parameters that are relevant to mass rearing in a production facility. Further, three lines performed well in male mating success and male competition assays, suggesting they would be sexually competitive in the field. Consequently, one transgenic line has been selected by the New World Screwworm Program for evaluation under mass rearing conditions. Conclusions We conclude that the promising characteristics of the selected sexing strains may contribute to reduce production costs for the existing eradication program and provide more efficient population suppression, which should make a genetic control program more economical in regions were C. hominivorax remains endemic. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0296-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Carolina Concha
- Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.,Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG), Pacora, Panama.,Smithsonian Tropical Research Institute, Naos Molecular Laboratory, Panama City, Panama
| | - Azhahianambi Palavesam
- USDA-ARS, Tick and Biting Fly Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA.,Present address: Department of Veterinary Parasitology, Madras Veterinary College, Tamil Nadu Veterinary and Animal Sciences University, Chennai, India
| | - Felix D Guerrero
- USDA-ARS, Tick and Biting Fly Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA
| | | | - Fang Li
- Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA
| | - Jason A Osborne
- Department of Statistics, North Carolina State University, Campus Box 8203, Raleigh, NC, 27695-8203, USA
| | - Yillian Hernandez
- Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG), Pacora, Panama
| | | | | | | | | | - Pamela L Phillips
- USDA-ARS, Screwworm Research Unit, Pacora, Panama.,USDA-ARS, Screwworm Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA
| | - John B Welch
- USDA-APHIS, IS Action Programs, 2881 F&B Road, College Station, TX, 77845, USA
| | - W Owen McMillan
- Smithsonian Tropical Research Institute, Naos Molecular Laboratory, Panama City, Panama
| | - Steven R Skoda
- USDA-ARS, Screwworm Research Unit, Pacora, Panama.,USDA-ARS, Screwworm Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA
| | - Maxwell J Scott
- Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.
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Linger RJ, Belikoff EJ, Scott MJ. Dosage Compensation of X-Linked Muller Element F Genes but Not X-Linked Transgenes in the Australian Sheep Blowfly. PLoS One 2015; 10:e0141544. [PMID: 26506426 PMCID: PMC4624761 DOI: 10.1371/journal.pone.0141544] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 10/10/2015] [Indexed: 11/25/2022] Open
Abstract
In most animals that have X and Y sex chromosomes, chromosome-wide mechanisms are used to balance X-linked gene expression in males and females. In the fly Drosophila melanogaster, the dosage compensation mechanism also generally extends to X-linked transgenes. Over 70 transgenic lines of the Australian sheep blowfly Lucilia cuprina have been made as part of an effort to develop male-only strains for a genetic control program of this major pest of sheep. All lines carry a constitutively expressed fluorescent protein marker gene. In all 12 X-linked lines, female larvae show brighter fluorescence than male larvae, suggesting the marker gene is not dosage compensated. This has been confirmed by quantitative RT-PCR for selected lines. To determine if endogenous X-linked genes are dosage compensated, we isolated 8 genes that are orthologs of genes that are on the fourth chromosome in D. melanogaster. Recent evidence suggests that the D. melanogaster fourth chromosome, or Muller element F, is the ancestral X chromosome in Diptera that has reverted to an autosome in Drosophila species. We show by quantitative PCR of male and female DNA that 6 of the 8 linkage group F genes reside on the X chromosome in L. cuprina. The other two Muller element F genes were found to be autosomal in L. cuprina, whereas two Muller element B genes were found on the same region of the X chromosome as the L. cuprina orthologs of the D. melanogaster Ephrin and gawky genes. We find that the L. cuprina X chromosome genes are equally expressed in males and females (i.e., fully dosage compensated). Thus, unlike in Drosophila, it appears that the Lucilia dosage compensation system is specific for genes endogenous to the X chromosome and cannot be co-opted by recently arrived transgenes.
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Affiliation(s)
- Rebecca J. Linger
- Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695–7613, United States of America
| | - Esther J. Belikoff
- Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695–7613, United States of America
| | - Maxwell J. Scott
- Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695–7613, United States of America
- * E-mail:
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