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Novas R, Basika T, Williamson ME, Fresia P, Menchaca A, Scott MJ. Identification and functional analysis of Cochliomyia hominivorax U6 gene promoters. INSECT MOLECULAR BIOLOGY 2023; 32:716-724. [PMID: 37732932 DOI: 10.1111/imb.12875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 08/04/2023] [Indexed: 09/22/2023]
Abstract
The New World screwworm, Cochliomyia hominivorax, is an obligate parasite, which is a major pest of livestock. While the sterile insect technique was used very successfully to eradicate C. hominivorax from North and Central America, more cost-effective genetic methods will likely be needed in South America. The recent development of CRISPR/Cas9-based genetic approaches, such as homing gene drive, could provide a very efficient means for the suppression of C. hominivorax populations. One component of a drive system is the guide RNA(s) driven by a U6 gene promoter. Here, we have developed an in vivo assay to evaluate the activity of the promoters from seven C. hominivorax U6 genes. Embryos from the related blowfly Lucilia cuprina were injected with plasmid DNA containing a U6-promoter-guide RNA construct and a source of Cas9, either protein or plasmid DNA. Activity was assessed by the number of site-specific mutations in the targeted gene in hatched larvae. One promoter, Chom U6_b, showed the highest activity. These U6 gene promoters could be used to build CRISPR/Cas9-based genetic systems for the control of C. hominivorax.
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Affiliation(s)
- Rossina Novas
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
- Pasteur+INIA Joint Unit, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Tatiana Basika
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
- Pasteur+INIA Joint Unit, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Megan E Williamson
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| | - Pablo Fresia
- Pasteur+INIA Joint Unit, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Alejo Menchaca
- Plataforma de Investigación en Salud Animal, Instituto Nacional de Investigación Agropecuaria (INIA), Montevideo, Uruguay
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
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Baltzegar JF, Gould F. Development of the first high-density linkage map in the maize weevil, Sitophilus zeamais. PeerJ 2023; 11:e15414. [PMID: 37337584 PMCID: PMC10276983 DOI: 10.7717/peerj.15414] [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: 12/09/2022] [Accepted: 04/24/2023] [Indexed: 06/21/2023] Open
Abstract
The maize weevil, Sitophilus zeamais, is a worldwide pest that disproportionately affects subsistence farmers in developing countries. Damage from this pest threatens food security in these communities as widely available and effective control methods are lacking. With advances over the last decade in the development of genetic pest management techniques, addressing pest issues at the ecosystem level as opposed to the farm level may be a possibility. However, pest species selected for genetic management techniques require a well-characterized genome and few genomic tools have been developed for S. zeamais. Here, we have measured the genome size and developed the first genetic linkage map for this species. The genome size was determined using flow cytometry as 682 Mb and 674 Mb for females and males, respectively. The linkage map contains 11 linkage groups, which correspond to the 10 autosomes and 1 X-chromosome found in the species and it contains 1,121 SNPs. This linkage map will be useful for assembling a complete genome for S. zeamais.
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Affiliation(s)
| | - Fred Gould
- Genetic Engineering and Society Center, North Carolina State University, Raleigh, NC, United States
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States
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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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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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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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Pimsler ML, Hjelmen CE, Jonika MM, Sharma A, Fu S, Bala M, Sze SH, Tomberlin JK, Tarone AM. Sexual Dimorphism in Growth Rate and Gene Expression Throughout Immature Development in Wild Type Chrysomya rufifacies (Diptera: Calliphoridae) Macquart. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.696638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Reliability of forensic entomology analyses to produce relevant information to a given case requires an understanding of the underlying arthropod population(s) of interest and the factors contributing to variability. Common traits for analyses are affected by a variety of genetic and environmental factors. One trait of interest in forensic investigations has been species-specific temperature-dependent growth rates. Recent work indicates sexual dimorphism may be important in the analysis of such traits and related genetic markers of age. However, studying sexual dimorphic patterns of gene expression throughout immature development in wild-type insects can be difficult due to a lack of genetic tools, and the limits of most sex-determination mechanisms. Chrysomya rufifacies, however, is a particularly tractable system to address these issues as it has a monogenic sex determination system, meaning females have only a single-sex of offspring throughout their life. Using modified breeding procedures (to ensure single-female egg clutches) and transcriptomics, we investigated sexual dimorphism in development rate and gene expression. Females develop slower than males (9 h difference from egg to eclosion respectively) even at 30°C, with an average egg-to-eclosion time of 225 h for males and 234 h for females. Given that many key genes rely on sex-specific splicing for the development and maintenance of sexually dimorphic traits, we used a transcriptomic approach to identify different expression of gene splice variants. We find that 98.4% of assembled nodes exhibited sex-specific, stage-specific, to sex-by-stage specific patterns of expression. However, the greatest signal in the expression data is differentiation by developmental stage, indicating that sexual dimorphism in gene expression during development may not be investigatively important and that markers of age may be relatively independent of sex. Subtle differences in these gene expression patterns can be detected as early as 4 h post-oviposition, and 12 of these nodes demonstrate homology with key Drosophila sex determination genes, providing clues regarding the distinct sex determination mechanism of C. rufifacies. Finally, we validated the transcriptome analyses through qPCR and have identified five genes that are developmentally informative within and between sexes.
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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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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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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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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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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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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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Functional characterization of the Drosophila suzukii pro-apoptotic genes reaper, head involution defective and grim. Apoptosis 2020; 25:864-874. [PMID: 33113043 DOI: 10.1007/s10495-020-01640-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2020] [Indexed: 12/18/2022]
Abstract
Apoptosis is a fundamental process for the elimination of damaged or unwanted cells, and is a key aspect of development. It is triggered by pro-apoptotic genes responding to the intrinsic pathway that senses cell stress or the extrinsic pathway that responds to signals from other cells. The disruption of these genes can therefore lead to developmental defects and disease. Pro-apoptotic genes have been studied in detail in the fruit fly Drosophila melanogaster, a widely-used developmental model. However, little is known about the corresponding genes in its relative D. suzukii, a pest of soft fruit crops that originates from Asia but is now an invasive species in many other regions. The characterization of D. suzukii pro-apoptotic genes could lead to the development of transgenic sexing strains for pest management. Here, we describe the isolation and characterization of the pro-apoptotic genes reaper (Dsrpr), head involution defective (Dshid) and grim (Dsgrim) from a laboratory strain of D. suzukii. We determined their expression profiles during development, revealing that all three genes are expressed throughout development but Dsrpr is expressed most strongly, especially at the pupal stage. Functional analysis was carried out by expressing single genes or pairs (linked by a 2A peptide) in S2 cell death assays, indicating that Dsgrim and Dshid are more potent pro-apoptotic genes than Dsrpr, and the lethality can be significantly enhanced by co-expression of two genes. Therefore, the binary or multiple expression of different pro-apoptotic genes can be considered to build an efficient transgenic sexing system in D. suzukii.
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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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Peng W, Yu S, Handler AM, Zhang H. Transcriptome Analysis of the Oriental Fruit Fly Bactrocera dorsalis Early Embryos. INSECTS 2020; 11:insects11050323. [PMID: 32456171 PMCID: PMC7290859 DOI: 10.3390/insects11050323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/28/2020] [Accepted: 04/28/2020] [Indexed: 12/01/2022]
Abstract
The oriental fruit fly, Bactrocera dorsalis (Hendel), is one of the most devastating and highly invasive agricultural pests world-wide, resulting in severe economic loss. Thus, it is of great interest to understand the transcriptional changes that occur during the activation of its zygotic genome at the early stages of embryonic development, especially the expression of genes involved in sex determination and the cellularization processes. In this study, we applied Illumina sequencing to identify B. dorsalis sex determination genes and early zygotic genes by analyzing transcripts from three early embryonic stages at 0–1, 2–4, and 5–8 h post-oviposition, which include the initiation of sex determination and cellularization. These tests generated 13,489 unigenes with an average length of 2185 bp. In total, 1683, 3201 and 3134 unigenes had significant changes in expression levels at times after oviposition including at 2–4 h versus 0–1 h, 5–8 h versus 0–1 h, and 5–8 h versus 2–4 h, respectively. Clusters of gene orthology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations were performed throughout embryonic development to better understand the functions of differentially expressed unigenes. We observed that the RNA binding and spliceosome pathways were highly enriched and overrepresented during the early stage of embryogenesis. Additionally, transcripts for 21 sex-determination and three cellularization genes were identified, and expression pattern analysis revealed that the majority of these genes were highly expressed during embryogenesis. This study is the first assembly performed for B. dorsalis based on Illumina next-generation sequencing technology during embryogenesis. Our data should contribute significantly to the fundamental understanding of sex determination and early embryogenesis in tephritid fruit flies, and provide gene promoter and effector gene candidates for transgenic pest-management strategies for these economically important species.
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Affiliation(s)
- Wei Peng
- Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, China-Australia Joint Research Centre for Horticultural and Urban Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (W.P.); (S.Y.)
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China
| | - Shuning Yu
- Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, China-Australia Joint Research Centre for Horticultural and Urban Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (W.P.); (S.Y.)
| | - Alfred M. Handler
- USDA/ARS, Center for Medical, Agricultural and Veterinary Entomology, 1700 SW 23rd Drive, Gainesville, FL 32608, USA;
| | - Hongyu Zhang
- Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, China-Australia Joint Research Centre for Horticultural and Urban Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (W.P.); (S.Y.)
- Correspondence:
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