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The transformer-2 and fruitless characterisation with developmental expression profiles of sex-determining genes in Bactrocera dorsalis and B. correcta. Sci Rep 2020; 10:17938. [PMID: 33087807 PMCID: PMC7578103 DOI: 10.1038/s41598-020-74856-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022] Open
Abstract
Sex determination in tephritid fruit flies involves a signaling cascade of alternatively spliced genes. The Transformer (TRA) and Transformer-2 (TRA-2) complex establishes an autoregulatory loop switching sex-specific splicing of tra pre-mRNA in females. The TRA/TRA-2 complex also regulates the sex-specific splicing of downstream effector genes, doublesex (dsx) and fruitless (fru). In Ceratitis capitata, a Maleness-on the-Y (MoY) gene modulates sex-specifically spliced Cctra pre-mRNA and results in the breakdown of the Cctra autoregulatory loop in males. In this study, the tra-2 and fru genes were characterised in two key pests, Bactrocera dorsalis and B. correcta. The tra-2 genes showed high degrees of conservation among tephritids. The complex gene organisation for each of Bdfru and Bcfru were identified. There are sex-specific and non sex-specific transcripts generated by alternative promoters as found in Drosophila melanogaster and other insects. RNAi knockdown of Bdtra transcripts showed that BdTRA controls the sex-specific splicing of Bddsx and Bdfru pre-mRNAs. Developmental expression analysis shows that multiple splice variants of Bdtra and Bctra RNAs are present before and during cellular blastoderm formation and that the mature sex-specific variants become fixed later in embryogenesis. Furthermore, the BddsxM splice variants are found in early embryos at the beginning of gastulation, but BdfruM does not appear until the larval stage. We proposed that the zygotic tra loop is initiated in both female and male embryos before becoming automatised or abolished by MoY, respectively.
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Aguirre C, Olivares N, Hinrichsen P. An Efficient Duplex PCR Method for Sex Identification of the European Grapevine Moth Lobesia botrana (Lepidoptera: Tortricidae) at Any Developmental Stage. JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:2505-2510. [PMID: 32676656 DOI: 10.1093/jee/toaa155] [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: 03/14/2020] [Indexed: 06/11/2023]
Abstract
Many genetic studies in insects require sex identification of individuals in all developmental stages. The most common sex chromosome system in lepidopterans is WZ/ZZ; the W chromosome is present only in females. Based on two W chromosome-specific short sequences (CpW2 and CpW5) described in Cydia pomonella (L.) (Lepidoptera: Tortricidae), we identified homologous female-specific sequences in Lobesia botrana Den. & Schiff, a polyphagous and very harmful species present in Chile since 2008. From this starting point, we extended the sequence information using the inverse PCR method, identifying the first W-specific sequences described up to now for the moth. Finally, we developed a duplex PCR method for rapid and sensitive determination of sex in L. botrana from larva to adult. The method showed a detection limit of 1 pg of genomic DNA; a blind panel of samples exhibited exact correspondence with the morphological identification. These results will be very useful for studies requiring sex-specific analyses at any developmental stage, contributing also to the understanding of gene expression in the insect, as well as to the eventual development of control protocols against the moth, such as the development of genetic sexing strains for the implementation of the sterile insect technique.
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Affiliation(s)
- Carlos Aguirre
- Instituto de Investigaciones Agropecuarias, INIA-La Platina, Santiago, Chile
| | - Natalia Olivares
- Instituto de Investigaciones Agropecuarias, INIA-La Cruz, La Cruz, Quillota, Chile
| | - Patricio Hinrichsen
- Instituto de Investigaciones Agropecuarias, INIA-La Platina, Santiago, Chile
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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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Belousova I, Ershov N, Pavlushin S, Ilinsky Y, Martemyanov V. Molecular sexing of Lepidoptera. JOURNAL OF INSECT PHYSIOLOGY 2019; 114:53-56. [PMID: 30776424 DOI: 10.1016/j.jinsphys.2019.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 02/14/2019] [Accepted: 02/14/2019] [Indexed: 06/09/2023]
Abstract
We developed a universal method of Lepidoptera molecular sexing. The method is based on comparing the number of copies of the same gene in different sexes. Males of the majority of lepidopteran species have two Z chromosomes, whereas females have only one Z chromosome. Correspondingly, the number of copies of each gene located on this chromosome differs by two times between males and females. For quantitative estimation, we used qPCR. Via multiple alignment of the kettin (a Z chromosome gene) nucleotide sequences, we detected the most conserved fragment and designed primers with broad interspecies specificity for Lepidoptera. Using these primers, we successfully determined the sex of three lepidopteran species belonging to different superfamilies. The developed method is a simple, cost-effective and high-throughput technique for routine sexing. The sex of lepidopteran individuals can be examined at any developmental stage.
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Affiliation(s)
- Irina Belousova
- Institute of Systematics and Ecology of Animals SB RAS, Frunze Str. 11, Novosibirsk 630091 Russia.
| | - Nikita Ershov
- Institute of Cytology and Genetics SB RAS, Prospekt Lavrentyeva 10, Novosibirsk 630090, Russia
| | - Sergey Pavlushin
- Institute of Systematics and Ecology of Animals SB RAS, Frunze Str. 11, Novosibirsk 630091 Russia
| | - Yury Ilinsky
- Institute of Cytology and Genetics SB RAS, Prospekt Lavrentyeva 10, Novosibirsk 630090, Russia; Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia; School of Life Sciences Immanuel Kant Baltic Federal University, Nevskogo Str. 14, Kaliningrad 236016, Russia
| | - Vyacheslav Martemyanov
- Institute of Systematics and Ecology of Animals SB RAS, Frunze Str. 11, Novosibirsk 630091 Russia; Biological Institute, National Research Tomsk State University, Lenin Ave. 36, Tomsk 634050, Russia
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Huang CY, Dai SM, Chang C. Introduction of the RTA-Bddsx gene induces female-specific lethal effects in transformed Bactrocera dorsalis (Hendel). PEST MANAGEMENT SCIENCE 2016; 72:1160-1167. [PMID: 26269247 DOI: 10.1002/ps.4094] [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: 04/16/2015] [Revised: 07/24/2015] [Accepted: 08/10/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND The oriental fruit fly, Bactrocera dorsalis (Hendel), can reduce fruit production and quality and is considered to be a major insect pest in many Asian countries. A system combining the toxicity of ricin and the alternative RNA splicing properties of doublesex (RTA-Bddsx) has been proposed that results in differential sexual processing in vitro. A transgenic approach was used in this study to confirm the existence of female-specific lethal effects in vivo. RESULTS The piggyBac-based vector PB-Acp-CF21-26, which carries the actin 5C promoter and RTA-Bddsx, was used to establish transgenic lines. Five surviving male flies (F1) demonstrated the presence of selection marker Ds-Red((+)) throughout their entire bodies following single-pair mating with wild-type females, indicating germline transmission. A high percentage of males (59.6-100%) were observed in transformed F3 offspring, and this skewed sex ratio indicated that the female-lethal effects of the RTA-Bddsx system were heritable and functioned well in B. dorsalis. Some transformed female flies were observed, and these unexpected results were attributed to the loss of the intact transgene after genomic PCR analyses. CONCLUSION This transgenic study provides direct evidence for the female-specific lethal effects of RTA-Bddsx in B. dorsalis and offers a novel and promising approach for the control of B. dorsalis in the future. © 2015 Society of Chemical Industry.
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Affiliation(s)
- Chun-Yen Huang
- Biotechnology Centre, National Chung-Hsing University, Taichung, Taiwan
| | - Shu-Mei Dai
- Department of Entomology, National Chung-Hsing University, Taichung, Taiwan
| | - Cheng Chang
- Biotechnology Centre, National Chung-Hsing University, Taichung, Taiwan
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Laohakieat K, Aketarawong N, Isasawin S, Thitamadee S, Thanaphum S. The study of the transformer gene from Bactrocera dorsalis and B. correcta with putative core promoter regions. BMC Genet 2016; 17:34. [PMID: 26833079 PMCID: PMC4736151 DOI: 10.1186/s12863-016-0342-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/25/2016] [Indexed: 12/31/2022] Open
Abstract
Background The transformer (tra) is a sex determining switch in different orders of insects, including Diptera, as in the family Tephritidae. The lifelong autoregulatory loop of tra female-specific splicing can be reset by the intervention of male-specific primary signals (M factor). In early development, the functional female and truncated male TRA proteins relay the sexual fates to the alternative splicing of a bisexual switch gene, doublesex (dsx) cascading the sexual differentiation processes. Bactrocera dorsalis (Hendel) and Bactrocera correcta (Bezzi) are among the Bactrocera model worldwide key pests. Area-wide integrated pest management using the male-only Sterile Insect Technique (SIT) relying on genetic sexing systems is effective in control programs. We undertook the molecular characterization and comparative studies of the tra orthologues in the Bactrocera species, including the Salaya1 genetic sexing strain (GSS). Results RT-PCR revealed that B. dorsalis tra (Bdtra) and B. correcta tra (Bctra) transcripts contained conservation of both constitutive exons and male-specific exons as in other Bactrocera. However, new Bdtra male-specific exons were retained, diversifying the pattern of the male-specifically spliced transcripts. The coding sequences of tra were highly conserved in Bactrocera (86–95 %) but less so among related genera (61–65 %) within the same Tephritidae family. A conservation of deduced amino acid sequences (18 residues), called the TEP region, was identified to be distinctive among tephritids. The 5’ regulatory sequence containing many structural characteristics of the putative core promoter was discovered in B. correcta. The expression patterns of Bdtra and Bctra were sex-specifically spliced and the signals relayed to the dsx genes in the adult wild-types. However, the coexistence of male- and female-specifically spliced transcripts (980 and 626 bp, respectively) of the B. dorsalis wild-type strain was found in the Salaya1 GSS adult males. The Bdtra RNA interference masculinized the XX karyotype females into pseudomales, but their testes were mostly not well developed. Conclusions Bdtra and Bctra have sex-specific splicing, similar to Bactroceras, Ceratitis capitata (Wiedemann), and Anastrephas. A newly identified TEP region is proposed in tephritids. A putative core promoter has been discovered in Bctra. Electronic supplementary material The online version of this article (doi:10.1186/s12863-016-0342-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kamoltip Laohakieat
- Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.
| | - Nidchaya Aketarawong
- Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.
| | - Siriwan Isasawin
- Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.
| | - Siripong Thitamadee
- Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.
| | - Sujinda Thanaphum
- Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.
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Dritsou V, Topalis P, Windbichler N, Simoni A, Hall A, Lawson D, Hinsley M, Hughes D, Napolioni V, Crucianelli F, Deligianni E, Gasperi G, Gomulski LM, Savini G, Manni M, Scolari F, Malacrida AR, Arcà B, Ribeiro JM, Lombardo F, Saccone G, Salvemini M, Moretti R, Aprea G, Calvitti M, Picciolini M, Papathanos PA, Spaccapelo R, Favia G, Crisanti A, Louis C. A draft genome sequence of an invasive mosquito: an Italian Aedes albopictus. Pathog Glob Health 2015; 109:207-20. [PMID: 26369436 PMCID: PMC4727573 DOI: 10.1179/2047773215y.0000000031] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The draft genome sequence of Italian specimens of the Asian tiger mosquito Aedes (Stegomyia) albopictus (Diptera: Culicidae) was determined using a standard NGS (next generation sequencing) approach. The size of the assembled genome is comparable to that of Aedes aegypti; the two mosquitoes are also similar as far as the high content of repetitive DNA is concerned, most of which is made up of transposable elements. Although, based on BUSCO (Benchmarking Universal Single-Copy Orthologues) analysis, the genome assembly reported here contains more than 99% of protein-coding genes, several of those are expected to be represented in the assembly in a fragmented state. We also present here the annotation of several families of genes (tRNA genes, miRNA genes, the sialome, genes involved in chromatin condensation, sex determination genes, odorant binding proteins and odorant receptors). These analyses confirm that the assembly can be used for the study of the biology of this invasive vector of disease.
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Affiliation(s)
- Vicky Dritsou
- Polo d'Innovazione di Genomica, Genetica e Biologia (Polo GGB), Loc. S. Andrea delle Fratte, Perugia, Italy
| | - Pantelis Topalis
- Institute of Molecular Biology and Biotechnology Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
| | - Nikolai Windbichler
- Imperial College London Department of Life Sciences, South Kensington Campus, UK
| | - Alekos Simoni
- Imperial College London Department of Life Sciences, South Kensington Campus, UK
| | - Ann Hall
- Imperial College London Department of Life Sciences, South Kensington Campus, UK
| | - Daniel Lawson
- European Molecular Biology Laboratory European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genomes Campus, Cambridge, Cambridgeshire, UK
| | - Malcolm Hinsley
- European Molecular Biology Laboratory European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genomes Campus, Cambridge, Cambridgeshire, UK
| | - Daniel Hughes
- European Molecular Biology Laboratory European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genomes Campus, Cambridge, Cambridgeshire, UK
| | - Valerio Napolioni
- Polo d'Innovazione di Genomica, Genetica e Biologia (Polo GGB), Loc. S. Andrea delle Fratte, Perugia, Italy
| | - Francesca Crucianelli
- Polo d'Innovazione di Genomica, Genetica e Biologia (Polo GGB), Loc. S. Andrea delle Fratte, Perugia, Italy
| | - Elena Deligianni
- Institute of Molecular Biology and Biotechnology Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
| | - Giuliano Gasperi
- Department of Biology and Biotechnology University of Pavia, Italy
| | | | - Grazia Savini
- Department of Biology and Biotechnology University of Pavia, Italy
| | - Mosè Manni
- Department of Biology and Biotechnology University of Pavia, Italy
| | | | | | - Bruno Arcà
- Department of Public Health and Infectious Diseases – Division of Parasitology Sapienza University of Rome, Italy
| | - José M. Ribeiro
- National Institute of Allergy and Infectious Diseases Bethesda, MD, USA
| | - Fabrizio Lombardo
- Department of Public Health and Infectious Diseases – Division of Parasitology Sapienza University of Rome, Italy
| | | | - Marco Salvemini
- Department of Biology University of Naples Federico II, Italy
| | - Riccardo Moretti
- ENEA – Italian National Agency for New Technologies Energy and Sustainable Economic Development, CR Casaccia, Rome, Italy
| | - Giuseppe Aprea
- ENEA – Italian National Agency for New Technologies Energy and Sustainable Economic Development, CR Casaccia, Rome, Italy
| | - Maurizio Calvitti
- ENEA – Italian National Agency for New Technologies Energy and Sustainable Economic Development, CR Casaccia, Rome, Italy
| | - Matteo Picciolini
- Polo d'Innovazione di Genomica, Genetica e Biologia (Polo GGB), Loc. S. Andrea delle Fratte, Perugia, Italy
| | | | | | - Guido Favia
- Scuola di Bioscienze e Medicina Veterinaria, University of Camerino, Italy
| | | | - Christos Louis
- Correspondence to: Christos Louis, IMBB-FORTH, N. Plastira 100, Vassilika Vouton, GR-700 13 Heraklion, Crete, Greece.
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Salvemini M, Arunkumar KP, Nagaraju J, Sanges R, Petrella V, Tomar A, Zhang H, Zheng W, Saccone G. De novo assembly and transcriptome analysis of the Mediterranean fruit fly Ceratitis capitata early embryos. PLoS One 2014; 9:e114191. [PMID: 25474564 PMCID: PMC4256415 DOI: 10.1371/journal.pone.0114191] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 11/05/2014] [Indexed: 01/04/2023] Open
Abstract
The agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or Medfly, belongs to the Tephritidae family, which includes a large number of other damaging pest species. The Medfly has been the first non-drosophilid fly species which has been genetically transformed paving the way for designing genetic-based pest control strategies. Furthermore, it is an experimentally tractable model, in which transient and transgene-mediated RNAi have been successfully used. We applied Illumina sequencing to total RNA preparations of 8–10 hours old embryos of C. capitata, This developmental window corresponds to the blastoderm cellularization stage. In summary, we assembled 42,614 transcripts which cluster in 26,319 unique transcripts of which 11,045 correspond to protein coding genes; we identified several hundreds of long ncRNAs; we found an enrichment of transcripts encoding RNA binding proteins among the highly expressed transcripts, such as CcTRA-2, known to be necessary to establish and, most likely, to maintain female sex of C. capitata. Our study is the first de novo assembly performed for Ceratitis capitata based on Illumina NGS technology during embryogenesis and it adds novel data to the previously published C. capitata EST databases. We expect that it will be useful for a variety of applications such as gene cloning and phylogenetic analyses, as well as to advance genetic research and biotechnological applications in the Medfly and other related Tephritidae.
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Affiliation(s)
- Marco Salvemini
- Department of Biology, University of Naples Federico II, Naples, Italy
| | | | | | - Remo Sanges
- Stazione Zoologica "Anton Dohrn", Naples, Italy
| | - Valeria Petrella
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Archana Tomar
- Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Hongyu Zhang
- State Key Laboratory of Agricultural Microbiology and Institute of Urban and Horticultural Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Weiwei Zheng
- State Key Laboratory of Agricultural Microbiology and Institute of Urban and Horticultural Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Giuseppe Saccone
- Department of Biology, University of Naples Federico II, Naples, Italy
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Salvemini M, D'Amato R, Petrella V, Ippolito D, Ventre G, Zhang Y, Saccone G. Subtractive and differential hybridization molecular analyses of Ceratitis capitata XX/XY versus XX embryos to search for male-specific early transcribed genes. BMC Genet 2014; 15 Suppl 2:S5. [PMID: 25472628 PMCID: PMC4255797 DOI: 10.1186/1471-2156-15-s2-s5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or Medfly, is a fruit crop pest of very high economic relevance in different continents. The strategy to separate Ceratitis males from females (sexing) in mass rearing facilities is a useful step before the sterilization and release of male-only flies in Sterile Insect Technique control programs (SIT). The identification of genes having early embryonic male-specific expression, including Y-linked genes, such as the Maleness factor, could help to design novel and improved methods of sexing in combination with transgenesis, aiming to confer conditional female-specific lethality or female-to-male sexual reversal. We used a combination of Suppression Subtractive Hybrydization (SSH), Mirror Orientation Selection (MOS) and differential screening hybridization (DSH) techniques to approach the problem of isolating corresponding mRNAs expressed in XX/XY embryos versus XX-only embryos during a narrow developmental window (8-10 hours after egg laying, AEL ). Here we describe a novel strategy we have conceived to obtain relatively large amounts of XX-only embryos staged at 8-10 h AEL and so to extract few micrograms of polyA+ required to apply the complex technical procedure. The combination of these 3 techniques led to the identification of a Y-linked putative gene, CcGm2, sharing high sequence identity to a paralogous gene, CcGm1, localized either on an autosome or on the X chromosome. We propose that CcGm2 is a first interesting putative Y-linked gene which could play a role in sex determination. The function exterted by this gene should be investigated by novel genetic tools, such as CRISPR-CAS9, which will permit to target only the Y-linked paralogue, avoiding to interfere with the autosomal or X-linked paralogue function.
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Eckermann KN, Dippel S, KaramiNejadRanjbar M, Ahmed HM, Curril IM, Wimmer EA. Perspective on the combined use of an independent transgenic sexing and a multifactorial reproductive sterility system to avoid resistance development against transgenic Sterile Insect Technique approaches. BMC Genet 2014; 15 Suppl 2:S17. [PMID: 25471733 PMCID: PMC4255789 DOI: 10.1186/1471-2156-15-s2-s17] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Background The Sterile Insect Technique (SIT) is an accepted species-specific genetic control approach that acts as an insect birth control measure, which can be improved by biotechnological engineering to facilitate its use and widen its applicability. First transgenic insects carrying a single killing system have already been released in small scale trials. However, to evade resistance development to such transgenic approaches, completely independent ways of transgenic killing should be established and combined. Perspective Most established transgenic sexing and reproductive sterility systems are based on the binary tTA expression system that can be suppressed by adding tetracycline to the food. However, to create 'redundant killing' an additional independent conditional expression system is required. Here we present a perspective on the use of a second food-controllable binary expression system - the inducible Q system - that could be used in combination with site-specific recombinases to generate independent transgenic killing systems. We propose the combination of an already established transgenic embryonic sexing system to meet the SIT requirement of male-only releases based on the repressible tTA system together with a redundant male-specific reproductive sterility system, which is activated by Q-system controlled site-specific recombination and is based on a spermatogenesis-specifically expressed endonuclease acting on several species-specific target sites leading to chromosome shredding. Conclusion A combination of a completely independent transgenic sexing and a redundant reproductive male sterility system, which do not share any active components and mediate the induced lethality by completely independent processes, would meet the 'redundant killing' criteria for suppression of resistance development and could therefore be employed in large scale long-term suppression programs using biotechnologically enhanced SIT.
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