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Chen B, Kou Z, Jiang Y, Luo X, Li P, Sun K, Wang W, Huang Y, Wang Y. Intersex is required for female sexual development in Hermetia illucens. INSECT SCIENCE 2023; 30:901-911. [PMID: 36719198 DOI: 10.1111/1744-7917.13179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/03/2023] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Sex-determination pathways are extremely diverse. Understanding the mechanism of sex determination in insects is important for genetic manipulation of the pest population and for breeding of economically valuable insects. Although sex determination has been well characterized in the model species Drosophila melanogaster, little is known about this pathway in Stratiomyidae. In the present study, we first identified the Drosophila intersex (ix) homolog in Hermetia illucens, also known as the black soldier fly, which belongs to the Stratiomyidae family and which is an important insect for the conversion of various organic wastes. Phylogenetic analyses and multiple sequence alignment revealed that Hiix is conserved compared with Drosophila. We showed that Hiix is highly expressed in internal genitalia. Disruption of the Hiix gene using CRISPR/Cas9 resulted in female-specific defects in external genitalia and abnormal and undersized ovaries. Taken together, our study furthers our understanding of sex determination in insects and could facilitate breeding of H. illucens.
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Affiliation(s)
- Bihui Chen
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, China
- Anhui Province Key Laboratory of Crop Integrated Pest Management, College of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Zongqing Kou
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, China
| | - Yuguo Jiang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, China
| | - Xingyu Luo
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, China
| | - Peili Li
- Beijing Dabeinong Technology Group Co., ltd., No. 19, Chengwan Street, Suyier Village, Sujiatuo Town, Haidian District, Beijing, China
| | - Kaiji Sun
- Beijing Dabeinong Technology Group Co., ltd., No. 19, Chengwan Street, Suyier Village, Sujiatuo Town, Haidian District, Beijing, China
| | - Weiwei Wang
- Beijing Dabeinong Technology Group Co., ltd., No. 19, Chengwan Street, Suyier Village, Sujiatuo Town, Haidian District, Beijing, China
| | - Yongping Huang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, China
| | - Yaohui Wang
- Anhui Province Key Laboratory of Crop Integrated Pest Management, College of Plant Protection, Anhui Agricultural University, Hefei, China
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Saccone G. A history of the genetic and molecular identification of genes and their functions controlling insect sex determination. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 151:103873. [PMID: 36400424 DOI: 10.1016/j.ibmb.2022.103873] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/01/2022] [Accepted: 11/02/2022] [Indexed: 06/16/2023]
Abstract
The genetics of the sex determination regulatory cascade in Drosophila melanogaster has a fascinating history, interlinked with the foundation of the Genetics discipline itself. The discovery that alternative splicing rather than differential transcription is the molecular mechanism underlying the upstream control of sex differences in the Drosophila model system was surprising. This notion is now fully integrated into the scientific canon, appearing in many genetics textbooks and online education resources. In the last three decades, it was a key reference point for starting evolutionary studies in other insect species by using homology-based approaches. This review will introduce a very brief history of Drosophila genetics. It will describe the genetic and molecular approaches applied for the identifying and cloning key genes involved in sex determination in Drosophila and in many other insect species. These comparative analyses led to supporting the idea that sex-determining pathways have evolved mainly by recruiting different upstream signals/genes while maintaining widely conserved intermediate and downstream regulatory genes. The review also provides examples of the link between technological advances and research achievements, to stimulate reflections on how science is produced. It aims to hopefully strengthen the related historical and conceptual knowledge of general readers of other disciplines and of younger geneticists, often focused on the latest technical-molecular approaches.
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Affiliation(s)
- Giuseppe Saccone
- Department of Biology, University of Naples Federico II, Via Cinthia 26, 80126, Naples, Italy.
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Pleiotropic Roles of the Orthologue of the Drosophila melanogaster Intersex Gene in the Brown Planthopper. Genes (Basel) 2021; 12:genes12030379. [PMID: 33800002 PMCID: PMC8000406 DOI: 10.3390/genes12030379] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/23/2021] [Accepted: 03/04/2021] [Indexed: 11/28/2022] Open
Abstract
Intersex(ix), a gene involved in the sex-determining cascade of Drosophila melanogaster, works in concert with the female-specific product of doublesex (dsx) at the end of the hierarchy to implement the sex-specific differentiation of sexually dimorphic characters in female individuals. In this study, the ix homolog was identified in the brown planthopper (BPH), Nilaparvata lugens, which contained two splice variants expressed in both female and male insects. We found that Nlix played a vital role in the early nymphal development of BPH, showing an accumulated effect. RNAi-mediated knockdown of Nlix at 4th instar led to the external genital defects in both sexes, consequently resulting in the loss of reproductive ability in female and male individuals. After dsRNA injection, the males were normal on testes, while the females had defective ovarian development. Nlix was also required for early embryogenesis. Notably, when the dsNlix microinjection was performed in newly emerged females, the copulatory bursas were abnormally enlarged while the other tissues of the reproductive system developed normally. Our results demonstrated the pleiotropic roles of Nlix in embryogenesis and development of the reproductive system in a hemimetabolous insect species.
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Liu Y, Yang J, Huo Z, Wang S, Wu Q, Zhou X, Xie W, Zhang Y. Characteristic and Functional Study of Intersex, a Gene Related to Female Fertility in Bemisia tabaci. Front Physiol 2020; 11:55. [PMID: 32158397 PMCID: PMC7052062 DOI: 10.3389/fphys.2020.00055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/21/2020] [Indexed: 12/18/2022] Open
Abstract
The intersex (ix) gene acts in concert with doublesex (dsx) at the end of the sex determination hierarchy to control somatic sexual differentiation in Drosophila melanogaster. Here, we report the Drosophila ix homolog in Bemisia tabaci (Btix) with differential splicing events. Four isoforms were found in B. tabaci adults, including two sex-specific transcripts (BtixF and BtixM). Knockdown of Btix had no measurable effects on female morphological phenotypes but reduced the expression of the vitellogenin gene and resulted in the production of significantly fewer eggs, a lower eclosion rate, and a shorter body size of female progeny in comparison with control females. These results increase our understanding of the genes underlying sex determination in B. tabaci and reveal a potential target for RNA interference-based pest management.
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Affiliation(s)
- Yating Liu
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jinjian Yang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhijia Huo
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shaoli Wang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qingjun Wu
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xuguo Zhou
- Department of Entomology, University of Kentucky, Lexington, KY, United States
| | - Wen Xie
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Youjun Zhang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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Xu J, Yu Y, Chen K, Huang Y. Intersex regulates female external genital and imaginal disc development in the silkworm. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 108:1-8. [PMID: 30831220 DOI: 10.1016/j.ibmb.2019.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/12/2019] [Accepted: 02/25/2019] [Indexed: 06/09/2023]
Abstract
As a component of the mediator complex, the intersex (ix) gene product is involved in the sex determination pathway of the Drosophila melanogaster. IX functions together with the female-specific product of doublesex (dsx) at the bottom of the hierarchy to implement female sexual differentiation. Here we analyzed the functions of the ix gene in the model lepidopteran insect Bombyx mori. We found that Bmix is expressed in many tissues and is highly expressed in early pupal stages. We used the transgene-based CRISPR/Cas9 system to generate mutants of the Bmix gene. The Bmix female mutants were sterile and had irregular external genitalia, whereas in the mutant males external genitalia were normal. Mutants of both sexes had normal gonad development and normal splicing of the Bmdsx pre-mRNA, suggesting that Bmix functions independently of Bmdsx. Interestingly, both male and female mutants had defective development of the imaginal disc including wing, antenna, and leg. RNA-seq and gene expression analyses indicated that genes involved in WNT, Hippo, and Hedgehog signaling pathways and wing development genes Bmawd and Bmfng were up-regulated or down-regulated in the Bmix mutants compared with wild-type animals. Our data provide insights into the multiple functions of Bmix in female external genital and imaginal disc development in the silkworm.
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Affiliation(s)
- Jun Xu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Ye Yu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Kai Chen
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yongping Huang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
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Verhulst EC, van de Zande L. Double nexus--Doublesex is the connecting element in sex determination. Brief Funct Genomics 2015; 14:396-406. [PMID: 25797692 PMCID: PMC4652034 DOI: 10.1093/bfgp/elv005] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
In recent years, our knowledge of the conserved master-switch gene doublesex (dsx) and its function in regulating the development of dimorphic traits in insects has deepened considerably. Here, a comprehensive overview is given on the properties of the male- and female-specific dsx transcripts yielding DSXF and DSXM proteins in Drosophila melanogaster, and the many downstream targets that they regulate. As insects have cell-autonomous sex determination, it was assumed that dsx would be expressed in every somatic cell, but recent research showed that dsx is expressed only when a cell is required to show its sexual identity through function or morphology. This spatiotemporal regulation of dsx expression has not only been established in D. melanogaster but in all insect species studied. Gradually, it has been appreciated that dsx could no longer be viewed as the master-switch gene orchestrating sexual development and behaviour in each cell, but instead should be viewed as the interpreter for the sexual identity of the cell, expressing this identity only on request, making dsx the central nexus of insect sex determination.
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Pomerantz AF, Hoy MA, Kawahara AY. Molecular characterization and evolutionary insights into potential sex-determination genes in the western orchard predatory miteMetaseiulus occidentalis(Chelicerata: Arachnida: Acari: Phytoseiidae). J Biomol Struct Dyn 2014; 33:1239-53. [DOI: 10.1080/07391102.2014.941402] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Nagaraju J, Gopinath G, Sharma V, Shukla J. Lepidopteran Sex Determination: A Cascade of Surprises. Sex Dev 2014; 8:104-12. [DOI: 10.1159/000357483] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Aspiras AC, Smith FW, Angelini DR. Sex-specific gene interactions in the patterning of insect genitalia. Dev Biol 2011; 360:369-80. [DOI: 10.1016/j.ydbio.2011.09.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 09/23/2011] [Accepted: 09/25/2011] [Indexed: 01/26/2023]
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