Pub Date : 2023-06-01DOI: 10.1016/j.ibmb.2023.103959
Tianran Li , Yinhao Ye , Peng Wu, Rengang Luo, Hongyu Zhang, Weiwei Zheng
Steroid hormone 20-hydroxyecdysone (20E) plays critical roles in reproductive development in dipterans and several other insect species. Ecdysteroidogenesis in the glands of larval or nymphal insects and other arthropods has been extensively studied, but that in the adult gonads remains largely unknown. Here we identified a proteasome β3 subunit (PSMB3) from a highly invasive pest Bactrocera dorsalis, and found that this gene was crucial for ecdysone production during female reproduction. PSMB3 was enriched in the ovary, and it was upregulated during sexual maturation. RNAi-mediated depletion of PSMB3 resulted in retarded ovarian development and decreased fecundity. Additionally, knockdown of PSMB3 reduced 20E titer in hemolymph of B. dorsalis. Molecularly, RNA sequencing and qPCR validation revealed that PSMB3 depletion suppressed the expression of 20E biosynthetic genes in the ovary and 20E responsive genes in the ovary and fat body. Furthermore, exogenous 20E rescued the inhibition of the ovarian development caused by PSMB3 depletion. Taken together, this study provides new insights into the adult reproductive development-related biological processes controlled by PSMB3, and proposed a potential eco-friendly control strategy against this notorious agricultural pest.
{"title":"Proteasome β3 subunit (PSMB3) controls female reproduction by promoting ecdysteroidogenesis during sexual maturation in Bactrocera dorsalis","authors":"Tianran Li , Yinhao Ye , Peng Wu, Rengang Luo, Hongyu Zhang, Weiwei Zheng","doi":"10.1016/j.ibmb.2023.103959","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103959","url":null,"abstract":"<div><p><span><span><span>Steroid hormone<span> 20-hydroxyecdysone (20E) plays critical roles in reproductive development in dipterans and several other insect species. Ecdysteroidogenesis in the glands of larval or nymphal insects and other arthropods has been extensively studied, but that in the adult </span></span>gonads remains largely unknown. Here we identified a </span>proteasome β3 subunit (</span><em>PSMB3</em><span>) from a highly invasive pest </span><span><em>Bactrocera dorsalis</em></span><span>, and found that this gene was crucial for ecdysone production during female reproduction</span><em>. PSMB3</em> was enriched in the ovary, and it was upregulated during sexual maturation. RNAi-mediated depletion of <em>PSMB3</em><span> resulted in retarded ovarian development and decreased fecundity. Additionally, knockdown of </span><em>PSMB3</em> reduced 20E titer in hemolymph of <em>B. dorsalis</em><span>. Molecularly, RNA sequencing and qPCR validation revealed that </span><em>PSMB3</em> depletion suppressed the expression of 20E biosynthetic genes in the ovary and 20E responsive genes in the ovary and fat body. Furthermore, exogenous 20E rescued the inhibition of the ovarian development caused by <em>PSMB3</em> depletion<em>.</em><span> Taken together, this study provides new insights into the adult reproductive development-related biological processes controlled by </span><em>PSMB3</em>, and proposed a potential eco-friendly control strategy against this notorious agricultural pest.</p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3209785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1016/j.ibmb.2023.103960
Judith Bossen , Jan-Philip Kühle , Thomas Roeder
The unique design of respiratory organs in multicellular organisms makes them prone to infection by pathogens. To cope with this vulnerability, highly effective local immune systems evolved that are also operative in the tracheal system of insects. Many pathogens and parasites (including viruses, bacteria, fungi, and metazoan parasites) colonize the trachea or invade the host via this route. Currently, only two modules of the tracheal immune system have been characterized in depth: 1) Immune deficiency pathway-mediated activation of antimicrobial peptide gene expression and 2) local melanization processes that protect the structure from wounding. There is an urgent need to increase our understanding of the architecture of tracheal immune systems, especially regarding those mechanisms that enable the maintenance of immune homeostasis. This need for new studies is particularly exigent for species other than Drosophila.
{"title":"The tracheal immune system of insects - A blueprint for understanding epithelial immunity","authors":"Judith Bossen , Jan-Philip Kühle , Thomas Roeder","doi":"10.1016/j.ibmb.2023.103960","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103960","url":null,"abstract":"<div><p><span>The unique design of respiratory organs in multicellular organisms makes them prone to infection by pathogens. To cope with this vulnerability, highly effective local immune systems evolved that are also operative in the tracheal system of insects. Many pathogens and parasites (including viruses, bacteria, fungi, and metazoan parasites) colonize the trachea or invade the host via this route. Currently, only two modules of the tracheal immune system have been characterized in depth: 1) Immune deficiency pathway-mediated activation of antimicrobial peptide<span><span> gene expression and 2) local melanization processes that protect the structure from wounding. There is an urgent need to increase our understanding of the architecture of tracheal immune systems, especially regarding those mechanisms that enable the maintenance of immune </span>homeostasis. This need for new studies is particularly exigent for species other than </span></span><em>Drosophila</em>.</p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1631979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-01DOI: 10.1016/j.ibmb.2023.103934
Adam Pym , John G.M. Mina , Bartlomiej J. Troczka , Angela Hayward , Eve Daum , Jan Elias , Russell Slater , John Vontas , Chris Bass , Christoph T. Zimmer
The tobacco whitefly, Bemisia tabaci, is a polyphagous crop pest which causes high levels of economic damage across the globe. Insecticides are often required for the effective control of this species, among which the neonicotinoid class have been particularly widely used. Deciphering the mechanisms responsible for resistance to these chemicals is therefore critical to maintain control of B. tabaci and limit the damage it causes. An important mechanism of resistance to neonicotinoids in B. tabaci is the overexpression of the cytochrome P450 gene CYP6CM1 which leads to the enhanced detoxification of several neonicotinoids. In this study we show that qualitative changes in this P450 dramatically alter its metabolic capacity to detoxify neonicotinoids. CYP6CM1 was significantly over-expressed in two strains of B. tabaci which displayed differing levels of resistance to the neonicotinoids imidacloprid and thiamethoxam. Sequencing of the CYP6CM1 coding sequence from these strains revealed four different alleles encoding isoforms carrying several amino acid changes. Expression of these alleles in vitro and in vivo provided compelling evidence that a mutation (A387G), present in two of the CYP6CM1 alleles, results in enhanced resistance to several neonicotinoids. These data demonstrate the importance of both qualitative and quantitative changes in genes encoding detoxification enzymes in the evolution of insecticide resistance and have applied implications for resistance monitoring programs.
{"title":"A single point mutation in the Bemisia tabaci cytochrome-P450 CYP6CM1 causes enhanced resistance to neonicotinoids","authors":"Adam Pym , John G.M. Mina , Bartlomiej J. Troczka , Angela Hayward , Eve Daum , Jan Elias , Russell Slater , John Vontas , Chris Bass , Christoph T. Zimmer","doi":"10.1016/j.ibmb.2023.103934","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103934","url":null,"abstract":"<div><p>The tobacco whitefly, <em>Bemisia tabaci</em>, is a polyphagous crop pest which causes high levels of economic damage across the globe. Insecticides are often required for the effective control of this species, among which the neonicotinoid class have been particularly widely used. Deciphering the mechanisms responsible for resistance to these chemicals is therefore critical to maintain control of <em>B. tabaci</em> and limit the damage it causes. An important mechanism of resistance to neonicotinoids in <em>B. tabaci</em> is the overexpression of the cytochrome P450 gene <em>CYP6CM1</em> which leads to the enhanced detoxification of several neonicotinoids. In this study we show that qualitative changes in this P450 dramatically alter its metabolic capacity to detoxify neonicotinoids. <em>CYP6CM1</em> was significantly over-expressed in two strains of <em>B. tabaci</em> which displayed differing levels of resistance to the neonicotinoids imidacloprid and thiamethoxam. Sequencing of the <em>CYP6CM1</em> coding sequence from these strains revealed four different alleles encoding isoforms carrying several amino acid changes. Expression of these alleles <em>in vitro</em> and <em>in vivo</em> provided compelling evidence that a mutation (A387G), present in two of the <em>CYP6CM1</em> alleles, results in enhanced resistance to several neonicotinoids. These data demonstrate the importance of both qualitative and quantitative changes in genes encoding detoxification enzymes in the evolution of insecticide resistance and have applied implications for resistance monitoring programs.</p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3020951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-01DOI: 10.1016/j.ibmb.2023.103947
Yunshan Zhang , Min Zhu , Jun Pan , Qunnan Qiu , Xinyu Tong , Xiaolong Hu , Chengliang Gong
Bombyx mori cypovirus (BmCPV), a typical double-stranded RNA virus, was demonstrated to generate a viral circRNA, vcircRNA_000048, which encodes a vsp21 with 21 amino acid residues to suppress viral replication. However, the regulatory mechanism of vsp21 on virus infection remained unclear. This study discovered that vsp21 induces reactive oxygen species (ROS) generation, activates autophagy, and attenuates virus replication by inducing autophagy. Then we confirmed that the effect of vsp21-induced autophagy on viral replication was attributed to the activation of the NF-κB signaling pathway. Furthermore, we clarified that vsp21 interacted with ubiquitin carboxyl-terminal hydrolase (UCH) and that ubiquitination and degradation of phospho-IκB-α were enhanced by vsp21 via competitive binding to UCH. Finally, we validated that vsp21 activates the NF-κB/autophagy pathway to suppress viral replication by interacting with UCH. These findings provided new insights into regulating viral multiplication and reovirus-host interaction.
家蚕双链病毒(Bombyx mori cypovirus, BmCPV)是一种典型的双链RNA病毒,它产生一个病毒环状RNA vcircRNA_000048,该环状RNA编码一个含有21个氨基酸残基的vsp21来抑制病毒复制。然而,vsp21对病毒感染的调控机制尚不清楚。本研究发现vsp21诱导活性氧(reactive oxygen species, ROS)产生,激活自噬,并通过诱导自噬减弱病毒复制。然后我们证实了vsp21诱导的自噬对病毒复制的影响归因于NF-κB信号通路的激活。此外,我们澄清了vsp21与泛素羧基末端水解酶(ubiquitin carboxyl-terminal hydrolase, UCH)相互作用,并且通过与UCH的竞争结合,vsp21增强了磷酸化i - κ b -α的泛素化和降解。最后,我们验证了vsp21通过与UCH相互作用激活NF-κB/自噬通路抑制病毒复制。这些发现为调节病毒增殖和呼肠孤病毒与宿主相互作用提供了新的见解。
{"title":"BmCPV replication is suppressed by the activation of the NF-κB/autophagy pathway through the interaction of vsp21 translated by vcircRNA_000048 with ubiquitin carboxyl-terminal hydrolase","authors":"Yunshan Zhang , Min Zhu , Jun Pan , Qunnan Qiu , Xinyu Tong , Xiaolong Hu , Chengliang Gong","doi":"10.1016/j.ibmb.2023.103947","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103947","url":null,"abstract":"<div><p><span><em>Bombyx mori</em></span><span><span><span> cypovirus (BmCPV), a typical double-stranded RNA virus, was demonstrated to generate a viral circRNA, vcircRNA_000048, which encodes a vsp21 with 21 </span>amino acid<span> residues to suppress viral replication. However, the regulatory mechanism of vsp21 on virus infection remained unclear. This study discovered that vsp21 induces reactive oxygen species (ROS) generation, activates autophagy, and attenuates virus replication by inducing autophagy. Then we confirmed that the effect of vsp21-induced autophagy on viral replication was attributed to the activation of the NF-κB signaling pathway<span>. Furthermore, we clarified that vsp21 interacted with ubiquitin carboxyl-terminal hydrolase (UCH) and that </span></span></span>ubiquitination<span> and degradation of phospho-IκB-α were enhanced by vsp21 via competitive binding to UCH. Finally, we validated that vsp21 activates the NF-κB/autophagy pathway to suppress viral replication by interacting with UCH. These findings provided new insights into regulating viral multiplication and reovirus-host interaction.</span></span></p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3020952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O-glycosylation of secreted and membrane-bound proteins is an important post-translational modification that affects recognition of cell surface receptors, protein folding, and stability. However, despite the importance of O-linked glycans, their biological functions have not yet been fully elucidated and the synthetic pathway of O-glycosylation has not been investigated in detail, especially in the silkworm. In this study, we aimed to investigate O-glycosylation in silkworms by analyzing the overall structural profiles of mucin-type O-glycans using LC–MS. We found GalNAc or GlcNAc monosaccharide and core 1 disaccharide (Galβ1-3-GalNAcα1-Ser/Thr) were major components of the O-glycan attached to secreted proteins produced in silkworms. Furthermore, we characterized the 1 b1,3-galactosyltransferase (T-synthase) required for synthesis of the core 1 structure, common to many animals. Five transcriptional variants and four protein isoforms were identified in silkworms, and the biological functions of these isoforms were investigated. We found that BmT-synthase isoforms 1 and 2 were localized in the Golgi apparatus in cultured BmN4 cells and functioned both in cultured cells and silkworms. Additionally, a specific functional domain of T-synthase, called the stem domain, was found to be essential for activity and is presumed to be needed for dimer formation and galactosyltransferase activity. Altogether, our results elucidated the O-glycan profile and function of T-synthase in the silkworm. Our findings allow the practical comprehension of O-glycosylation required for employing silkworms as a productive expression system.
{"title":"The biological role of core 1β1-3galactosyltransferase (T-synthase) in mucin-type O-glycosylation in Silkworm, Bombyx mori","authors":"Akihiro Morio , Jae Man Lee , Tsuguru Fujii , Hiroaki Mon , Akitsu Masuda , Kohei Kakino , Jian Xu , Yutaka Banno , Takahiro Kusakabe","doi":"10.1016/j.ibmb.2023.103936","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103936","url":null,"abstract":"<div><p><span>O-glycosylation of secreted and membrane-bound proteins is an important post-translational modification that affects recognition of cell surface receptors, protein folding, and stability. However, despite the importance of </span><em>O-</em><span>linked glycans, their biological functions have not yet been fully elucidated and the synthetic pathway of </span><em>O-</em><span>glycosylation<span> has not been investigated in detail, especially in the silkworm. In this study, we aimed to investigate </span></span><em>O-</em>glycosylation in silkworms by analyzing the overall structural profiles of mucin-type <em>O-</em><span><span>glycans using LC–MS. We found GalNAc or GlcNAc </span>monosaccharide<span> and core 1 disaccharide (Galβ1-3-GalNAcα1-Ser/Thr) were major components of the </span></span><em>O-</em><span>glycan attached to secreted proteins produced in silkworms. Furthermore, we characterized the 1 b1,3-galactosyltransferase (T-synthase) required for synthesis of the core 1 structure, common to many animals. Five transcriptional variants and four protein isoforms<span> were identified in silkworms, and the biological functions of these isoforms were investigated. We found that BmT-synthase isoforms 1 and 2 were localized in the Golgi apparatus in cultured </span></span><em>Bm</em><span><span>N4 cells and functioned both in cultured cells and silkworms. Additionally, a specific functional domain of T-synthase, called the stem domain, was found to be essential for activity and is presumed to be needed for dimer formation and </span>galactosyltransferase activity. Altogether, our results elucidated the </span><em>O</em>-glycan profile and function of T-synthase in the silkworm. Our findings allow the practical comprehension of <em>O-</em><span>glycosylation required for employing silkworms as a productive expression system.</span></p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1631982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lepidopteran insects are heterogametic in females, although most insect species are heterogametic in males. In a lepidopteran model species, the silkworm Bombyx mori (Bombycoidea), the uppermost sex determinant Feminizer (Fem) has been identified on the female-specific W chromosome. Fem is a precursor of PIWI-interacting small RNA (piRNA). Fem piRNA forms a complex with Siwi, one of the two B. mori PIWI-clade Argonaute proteins. In female embryos, Fem piRNA–Siwi complex cleaves the mRNA of the male-determining gene Masculinizer (Masc), directing the female-determining pathway. In male embryos, Masc activates the male-determining pathway in the absence of Fem piRNA. Recently, W chromosome-derived piRNAs complementary to Masc mRNA have also been identified in the diamondback moth Plutella xylostella (Yponomeutoidea), indicating the convergent evolution of piRNA-dependent sex determination in Lepidoptera. Here, we show that this is not the case in the Asian corn borer, Ostrinia furnacalis (Pyraloidea). Although our previous studies demonstrated that O. furnacalis Masc (OfMasc) has a masculinizing function in the embryonic stage, the expression level of OfMasc was indistinguishable between the sexes at the timing of sex determination. Deep sequencing analysis identified no female-specific small RNAs mapped onto OfMasc mRNA. Embryonic knockdown of two PIWI genes did not affect the expression level of OfMasc in either sex. These results demonstrated that piRNA-dependent reduction of Masc mRNA in female embryos is not a common strategy of sex determination, which suggests the possibility of divergent evolution of sex determinants across the order Lepidoptera.
{"title":"Masculinizer is not post-transcriptionally regulated by female-specific piRNAs during sex determination in the Asian corn borer, Ostrinia furnacalis","authors":"Takahiro Fukui , Keisuke Shoji , Takashi Kiuchi , Yutaka Suzuki , Susumu Katsuma","doi":"10.1016/j.ibmb.2023.103946","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103946","url":null,"abstract":"<div><p>Lepidopteran insects are heterogametic in females, although most insect species are heterogametic in males. In a lepidopteran model species, the silkworm <em>Bombyx mori</em> (Bombycoidea), the uppermost sex determinant <em>Feminizer</em> (<em>Fem</em>) has been identified on the female-specific W chromosome. <em>Fem</em> is a precursor of PIWI-interacting small RNA (piRNA). <em>Fem</em> piRNA forms a complex with Siwi, one of the two <em>B</em>. <em>mori</em> PIWI-clade Argonaute proteins. In female embryos, <em>Fem</em> piRNA–Siwi complex cleaves the mRNA of the male-determining gene <em>Masculinizer</em> (<em>Masc</em>), directing the female-determining pathway. In male embryos, <em>Masc</em> activates the male-determining pathway in the absence of <em>Fem</em> piRNA. Recently, W chromosome-derived piRNAs complementary to <em>Masc</em> mRNA have also been identified in the diamondback moth <em>Plutella xylostella</em> (Yponomeutoidea), indicating the convergent evolution of piRNA-dependent sex determination in Lepidoptera. Here, we show that this is not the case in the Asian corn borer, <em>Ostrinia furnacalis</em> (Pyraloidea). Although our previous studies demonstrated that <em>O</em>. <em>furnacalis Masc</em> (<em>OfMasc</em>) has a masculinizing function in the embryonic stage, the expression level of <em>OfMasc</em> was indistinguishable between the sexes at the timing of sex determination. Deep sequencing analysis identified no female-specific small RNAs mapped onto <em>OfMasc</em> mRNA. Embryonic knockdown of two <em>PIWI</em> genes did not affect the expression level of <em>OfMasc</em> in either sex. These results demonstrated that piRNA-dependent reduction of <em>Masc</em> mRNA in female embryos is not a common strategy of sex determination, which suggests the possibility of divergent evolution of sex determinants across the order Lepidoptera.</p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3342888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-01DOI: 10.1016/j.ibmb.2023.103938
Misato Okamoto Miyakawa, Hitoshi Miyakawa
Organisms that reproduce sexually have evolved well-organized mechanisms to determine two sexes. Some hymenopterans (such as ants, bees, and wasps) have a complementary sex-determination system in which heterozygosity at one CSD locus induces female development, whereas hemi- or homozygosity at the locus induces male development. This system can generate a high cost of inbreeding, as individuals that are homozygous at the locus become sterile, diploid males. On the other hand, some hymenopterans have evolved a multi-locus, complementary, sex-determination system in which heterozygosity in at least one CSD locus induces female development. This system effectively reduces the proportion of sterile diploid males; however, how these multiple primary signals based on CSD pass through a molecular cascade to regulate downstream genes has remained unclear. To clarify this matter, we used a backcross to investigate the molecular cascade in the ant, Vollenhovia emeryi, with two CSD loci. Here we show by gene disruption that transformer (tra) is necessary for proper feminization. Expression analysis of tra and doublesex (dsx) showed that heterozygosity in at least one of the two CSD loci is sufficient to promote female sex determination. Analysis of overexpression suggested that female-type Tra protein promotes splicing of tra pre-mRNA to female isoform by a positive-regulatory-feedback loop. Our data also showed that tra affects splicing of dsx. We conclude that two-loci sex determination system in V. emeryi evolved based on tra-dsx splicing cascade that is well conserved in other insect species. Finally, we suggest a cascade model to arrive at a binary determination of sex under multiple primary signals.
{"title":"Transformer gene regulates feminization under two complementary sex determination loci in the ant, Vollenhovia emeryi","authors":"Misato Okamoto Miyakawa, Hitoshi Miyakawa","doi":"10.1016/j.ibmb.2023.103938","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103938","url":null,"abstract":"<div><p>Organisms that reproduce sexually have evolved well-organized mechanisms to determine two sexes. Some hymenopterans (such as ants, bees, and wasps) have a complementary sex-determination system in which heterozygosity at one CSD locus induces female development, whereas hemi- or homozygosity at the locus induces male development. This system can generate a high cost of inbreeding, as individuals that are homozygous at the locus become sterile, diploid males. On the other hand, some hymenopterans have evolved a multi-locus, complementary, sex-determination system in which heterozygosity in at least one CSD locus induces female development. This system effectively reduces the proportion of sterile diploid males; however, how these multiple\u2028primary signals based on CSD pass through a molecular cascade to regulate downstream genes has remained unclear. To clarify this matter, we used a backcross to investigate the molecular cascade in the ant, <em>Vollenhovia emeryi</em>, with two CSD loci. Here we show by gene disruption that <em>transformer</em> (<em>tra</em>) is necessary for proper feminization. Expression analysis of <em>tra</em> and <em>doublesex</em> (<em>dsx</em>) showed that heterozygosity in at least one of the two CSD loci is sufficient to promote female sex determination. Analysis of overexpression suggested that female-type Tra protein promotes splicing of <em>tra</em> pre-mRNA to female isoform by a positive-regulatory-feedback loop. Our data also showed that <em>tra</em> affects splicing of <em>dsx</em>. We conclude that two-loci sex determination system in <em>V. emeryi</em> evolved based on <em>tra</em>-<em>dsx</em> splicing cascade that is well conserved in other insect species. Finally, we suggest a cascade model to arrive at a binary determination of sex under multiple primary signals.</p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1631983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-01DOI: 10.1016/j.ibmb.2023.103937
Chris Bass , Ralf Nauen
Aphids are a group of hemipteran insects that include some of the world's most economically important agricultural pests. The control of pest aphids has relied heavily on the use of chemical insecticides, however, the evolution of resistance poses a serious threat to their sustainable control. Over 1000 cases of resistance have now been documented for aphids involving a remarkable diversity of mechanisms that, individually or in combination, allow the toxic effect of insecticides to be avoided or overcome. In addition to its applied importance as a growing threat to human food security, insecticide resistance in aphids also offers an exceptional opportunity to study evolution under strong selection and gain insight into the genetic variation fuelling rapid adaptation. In this review we summarise the biochemical and molecular mechanisms underlying resistance in the most economically important aphid pests worldwide and the insights study of this topic has provided on the genomic architecture of adaptive traits.
{"title":"The molecular mechanisms of insecticide resistance in aphid crop pests","authors":"Chris Bass , Ralf Nauen","doi":"10.1016/j.ibmb.2023.103937","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103937","url":null,"abstract":"<div><p>Aphids are a group of hemipteran insects that include some of the world's most economically important agricultural pests. The control of pest aphids has relied heavily on the use of chemical insecticides, however, the evolution of resistance poses a serious threat to their sustainable control. Over 1000 cases of resistance have now been documented for aphids involving a remarkable diversity of mechanisms that, individually or in combination, allow the toxic effect of insecticides to be avoided or overcome. In addition to its applied importance as a growing threat to human food security, insecticide resistance in aphids also offers an exceptional opportunity to study evolution under strong selection and gain insight into the genetic variation fuelling rapid adaptation. In this review we summarise the biochemical and molecular mechanisms underlying resistance in the most economically important aphid pests worldwide and the insights study of this topic has provided on the genomic architecture of adaptive traits.</p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1631981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-01DOI: 10.1016/j.ibmb.2023.103948
Luca Finetti, Jimena Leyria, Ian Orchard, Angela B. Lange
In insects, the biogenic amine tyramine (TA) has been shown to control several physiological processes. Recently, the involvement of the type 1 tyramine receptor (TAR1) in reproductive processes has been demonstrated in different insects. Here, we investigate the putative role of Rhodnius prolixus TAR1 (RpTAR1) in reproduction in female R. prolixus. RpTAR1 transcript was highly expressed in tissues associated with egg development. Moreover, after a blood meal, which is the stimulus for full egg development, RpTAR1 transcript was upregulated in the ovaries and in the fat body. After RNAi-mediated RpTAR1 knockdown, an ovarian phenotype characterized by the absence or reduction of egg production was observed. Furthermore, protein and Vg accumulation in the fat body was observed, suggesting an impairment in protein release from the fat body into the hemolymph. However, even though fewer eggs were produced and laid, there was no difference in hatching ratio of those laid, in comparison to the controls, indicating that the overall low protein uptake by the ovaries did not influence the viability of individual eggs produced. Interestingly, the eggs from dsTAR1-treated insects appeared more red, indicating a higher content of RHBP compared to the control. A higher colocalization between Vg and Rab11, a marker for the recycling endosome pathway, was observed after dsTAR1 injection, suggesting that a more active lysosome degradation pathway in response to the Vg accumulation may occur. In addition to the Vg accumulation in the fat body, dsTAR1 treatment altered JH pathway. However, it remains to be elucidated whether this event is either directly related to the RpTAR1 downregulation or for a consequence to the Vg accumulation. Lastly, the RpTAR1 action on Vg synthesis and release in the fat body was monitored in the presence or absence of yohimbine, the antagonist of TAR1, in an ex-vivo experiment. Yohimbine antagonises the TAR1 stimulated release of Vg. These results provide critical information concerning the role of TAR1 in Vg synthesis and release in R. prolixus. Furthermore, this work opens the way for further investigation into innovative methods for controlling R. prolixus.
{"title":"Tyraminergic control of vitellogenin production and release in the blood-feeding insect, Rhodnius prolixus","authors":"Luca Finetti, Jimena Leyria, Ian Orchard, Angela B. Lange","doi":"10.1016/j.ibmb.2023.103948","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103948","url":null,"abstract":"<div><p>In insects, the biogenic amine tyramine (TA) has been shown to control several physiological processes. Recently, the involvement of the type 1 tyramine receptor (TAR1) in reproductive processes has been demonstrated in different insects. Here, we investigate the putative role of <em>Rhodnius prolixus</em> TAR1 (RpTAR1) in reproduction in female <em>R. prolixus</em>. RpTAR1 transcript was highly expressed in tissues associated with egg development. Moreover, after a blood meal, which is the stimulus for full egg development, <em>RpTAR1</em> transcript was upregulated in the ovaries and in the fat body. After RNAi-mediated RpTAR1 knockdown, an ovarian phenotype characterized by the absence or reduction of egg production was observed. Furthermore, protein and Vg accumulation in the fat body was observed, suggesting an impairment in protein release from the fat body into the hemolymph. However, even though fewer eggs were produced and laid, there was no difference in hatching ratio of those laid, in comparison to the controls, indicating that the overall low protein uptake by the ovaries did not influence the viability of individual eggs produced. Interestingly, the eggs from dsTAR1-treated insects appeared more red, indicating a higher content of RHBP compared to the control. A higher colocalization between Vg and Rab11, a marker for the recycling endosome pathway, was observed after dsTAR1 injection, suggesting that a more active lysosome degradation pathway in response to the Vg accumulation may occur. In addition to the Vg accumulation in the fat body, dsTAR1 treatment altered JH pathway. However, it remains to be elucidated whether this event is either directly related to the RpTAR1 downregulation or for a consequence to the Vg accumulation. Lastly, the RpTAR1 action on Vg synthesis and release in the fat body was monitored in the presence or absence of yohimbine, the antagonist of TAR1, in an ex-vivo experiment. Yohimbine antagonises the TAR1 stimulated release of Vg. These results provide critical information concerning the role of TAR1 in Vg synthesis and release in <em>R. prolixus</em>. Furthermore, this work opens the way for further investigation into innovative methods for controlling <em>R. prolixus</em>.</p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3342887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-01DOI: 10.1016/j.ibmb.2023.103935
M. Rumbo, V. Pagone, M.D. Piulachs
Ecdysone regulates essential processes in insect life. Perhaps the most well-known of these are related to metamorphosis. However, ecdysone is also required to regulate the proliferation and differentiation of germ cells in the ovary. The role of ecdysone in insect oogenesis has been studied in depth in holometabolan species with meroistic ovaries, such as Drosophila melanogaster, while in hemimetabolan species with panoistic ovaries their functions are still poorly understood. In the present work, we studied the role of ecdysone in the ovary of the last nymphal instar of the cockroach Blattella germanica by using RNA interference to reduce the levels of the ecdysone receptor (EcR), and thereby deplete the expression of ecdysteroidogenic genes in the prothoracic gland. However, the expression of ecdysteroidogenic genes was upregulated in the ovary, resulting in cell overproliferation in the germarium, which appeared swollen. By analysing the expression of genes that respond to ecdysone, we found that when the source of 20E is the nymphal ovary, EcR appears to repress 20E-associated genes bypassing early genes signalling.
{"title":"Diverse functions of the ecdysone receptor (EcR) in the panoistic ovary of the German cockroach","authors":"M. Rumbo, V. Pagone, M.D. Piulachs","doi":"10.1016/j.ibmb.2023.103935","DOIUrl":"https://doi.org/10.1016/j.ibmb.2023.103935","url":null,"abstract":"<div><p><span><span>Ecdysone<span> regulates essential processes in insect life. Perhaps the most well-known of these are related to metamorphosis. However, ecdysone is also required to regulate the proliferation and differentiation of germ cells in the ovary. The role of ecdysone in insect oogenesis has been studied in depth in </span></span>holometabolan species with meroistic ovaries, such as </span><span><em>Drosophila melanogaster</em></span><span><span>, while in hemimetabolan species with panoistic ovaries their functions are still poorly understood. In the present work, we studied the role of ecdysone in the ovary of the last nymphal instar of the </span>cockroach </span><span><em>Blattella germanica</em></span><span> by using RNA interference<span> to reduce the levels of the ecdysone receptor (</span></span><em>EcR</em><span>), and thereby deplete the expression of ecdysteroidogenic genes in the prothoracic gland. However, the expression of ecdysteroidogenic genes was upregulated in the ovary, resulting in cell overproliferation in the germarium, which appeared swollen. By analysing the expression of genes that respond to ecdysone, we found that when the source of 20E is the nymphal ovary, </span><em>EcR</em> appears to repress 20E-associated genes bypassing early genes signalling.</p></div>","PeriodicalId":330,"journal":{"name":"Insect Biochemistry and Molecular Biology","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2894008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}