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1.
PLoS Negl Trop Dis ; 14(8): e0008669, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32866146

RESUMO

Exposure of adult mosquitoes to pyriproxyfen (PPF), an analog of insect juvenile hormone (JH), has shown promise to effectively sterilize female mosquitoes. However, the underlying mechanisms of the PPF-induced decrease in mosquito fecundity are largely unknown. We performed a comprehensive study to dissect the mode of PPF action in Aedes aegypti mosquitoes. Exposure to PPF prompted the overgrowth of primary follicles in sugar-fed Ae. aegypti females but blocked the development of primary follicles at Christopher's Stage III after blood feeding. Secondary follicles were precociously activated in PPF-treated mosquitoes. Moreover, PPF substantially altered the expression of many genes that are essential for mosquito physiology and oocyte development in the fat body and ovary. In particular, many metabolic genes were differentially expressed in response to PPF treatment, thereby affecting the mobilization and utilization of energy reserves. Furthermore, PPF treatment on the previtellogenic female adults considerably modified mosquito responses to JH and 20-hydroxyecdysone (20E), two major hormones that govern mosquito reproduction. Krüppel homolog 1, a JH-inducible transcriptional regulator, showed consistently elevated expression after PPF exposure. Conversely, PPF upregulated the expression of several key players of the 20E regulatory cascades, including HR3 and E75A, in the previtellogenic stage. After blood-feeding, the expression of these 20E response genes was significantly weaker in PPF-treated mosquitoes than the solvent-treated control groups. RNAi-mediated knockdown of the Methoprene-tolerant (Met) protein, the JH receptor, partially rescued the impaired follicular development after PPF exposure and substantially increased the hatching of the eggs produced by PPF-treated female mosquitoes. Thus, the results suggested that PPF relied on Met to exert its sterilizing effects on female mosquitoes. In summary, this study finds that PPF exposure disturbs normal hormonal responses and metabolism in Ae. aegypti, shedding light on the molecular targets and the downstream signaling pathways activated by PPF.


Assuntos
Aedes/efeitos dos fármacos , Culicidae/efeitos dos fármacos , Inseticidas/farmacologia , Metoprene/metabolismo , Esterilização , Animais , Ecdisterona/farmacologia , Corpo Adiposo/crescimento & desenvolvimento , Feminino , Glicogênio/metabolismo , Proteínas de Insetos/genética , Hormônios Juvenis/farmacologia , Ovário/crescimento & desenvolvimento , Piridinas , Interferência de RNA , Triglicerídeos/metabolismo
2.
Pestic Biochem Physiol ; 170: 104676, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32980056

RESUMO

Acetamiprid is a new neonicotinoid insecticide widely used in the prevention and control of pests in agriculture. However, its residues in the environment affect the cocooning of the silkworm, Bombyx mori (B. mori), a non-target insect. To investigate the mechanism of damage, B. mori larvae were fed with trace amounts of acetamiprid (0.15 mg/L). At 96 h after exposure, the larvae showed signs of poisoning and decreased body weight, resulting in reduced survival and ratio of cocoon shell. At 48 h and 96 h after exposure, the residues in the posterior silk gland (PSG), which is responsible for synthesizing silk fibroin, were 0.72 µg/mg and 1.21 µg/mg, respectively, as measured by high performance liquid chromatography, indicating that acetamiprid can accumulate in the PSG. Moreover, pathological sections and transmission electron microscopy also demonstrate the damage of the PSG by acetamiprid. Digital gene expression (DGE) and KEGG pathway enrichment analysis revealed that genes related to metabolism, stress responses and inflammation were significantly up-regulated after exposure. Quantitative RT-PCR analysis showed that the transcript levels of FMBP-1 and FTZ-F1 (transcription factors for synthesizing silk protein) were up-regulated by 2.55-and 1.56-fold, respectively, and the transcript levels of fibroin heavy chain (Fib-H), fibroin light chain (Fib-L), P25, Bmsage and Bmdimm were down-regulated by 0.75-, 0.76-, 0.65-, 0.44- and 0.40-fold, respectively. The results indicate that accumulated acetamiprid causes damage to the PSG and leads to reduced expression of genes responsible for synthesizing silk fibroin. Our data provide reference for evaluating the safety of acetamiprid residues in the environment for non-target insects.


Assuntos
Bombyx/genética , Fibroínas , Animais , Proteínas de Insetos/genética , Neonicotinoides/toxicidade , Seda
3.
Pestic Biochem Physiol ; 170: 104685, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32980060

RESUMO

Sublethal doses of chlorantraniliprole (CAP) disrupt spinning disorder in the silkworm Bombyx mori (B. mori) and cause reduced cocoon production. In the present study, we investigated the effects of trace amounts of CAP on morphology and gene expression of the B. mori silk gland, found the posterior silk gland cells were possessed of disintegrated Endoplasmic reticulum (ER), unevenly distributed chromatin after exposure to CAP (0.01 mg/L). Gene expression analysis revealed that IRE1 and ATF6 ER stress-signaling pathways were inhibited, the PERK/CncC pathway was activated. Digital gene expression (DGE) analysis showed that detoxification-related genes, antioxidant genes and genes involved in ER protein processing pathway were expressed differentially in CAP-treated silkworm larvae. Notably, the transcript levels of the detoxification-related genes (CYP4M5, CYP6AB4, GSTD3 and GSTS1) and the antioxidant genes (CAT, TPX and SOD) were significantly increased, and the expression of ER protein processing-related genes (Sec61ß, Sec61γ, Sec23α and ERGIC-53) was significantly decreased after CAP exposure. The results showed that sublethal doses of CAP exposure caused ER stress, oxidative damage to the silk gland and the perturbation of protein processing in ER, thereby probably leading to abnormal growth of the silk gland and triggering the spinning failure in silkworm.


Assuntos
Bombyx/genética , Animais , Antioxidantes , Proteínas de Insetos/genética , Larva/genética , Seda , ortoaminobenzoatos/toxicidade
4.
Pestic Biochem Physiol ; 169: 104650, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32828368

RESUMO

Sex pheromone-based pest management technology has been widely used to monitor and control insect pests in the agricultural, forestry, and public health sectors. Scopula subpunctaria is a widespread tea pest in China with Type II sex pheromone components. However, limited information is available on the biosynthesis and transportation of Type II sex pheromone components. In this study, we constructed an S. subpunctaria sex pheromone gland (PG) transcriptome and obtained 85,246 transcripts. Cytochrome P450 monooxygenases (CYPs) thought to epoxidize dienes and trienes to epoxides in the PG and odorant-binding proteins (OBPs) and chemosensory genes (CSPs) thought to be responsible for the binding and transportation of sex pheromone components. In present study, a total of 79 CYPs, 29 OBPs and 17 CSPs were identified. We found that SsubCYP341A and SsubCYP341B_ortholog1 belonged to the CYP341 family and were more highly expressed in the PG than in the female body. Of these, SsubCYP341A was the seventh-most PG-enriched CYP in the PG transcriptome. Two CYP4 members, CYP340BD_ortholog2 and CYP4G, were the top two most PG-enriched CYPs. Tissue expression and phylogenetic tree analysis showed that SsubOBP25, 27, and 28 belonged to the moth pheromone-binding protein family; they were distinctly expressed in the antennae and were more abundant in male antennae than in female antennae. SsubCSP16 was distributed into the same clade as CSPs from other moths that showed high binding affinities to sex pheromone components. It indicated that all the above-mentioned genes could be involved in sex pheromone biosynthesis or transportation. Our study provides large-scale PG sequence information that can be used to identify potential targets for the biological control of S. subpunctaria by disrupting its sex pheromone biosynthesis and transportation pathways.


Assuntos
Mariposas/genética , Atrativos Sexuais , Animais , Antenas de Artrópodes , China , Sistema Enzimático do Citocromo P-450 , Feminino , Perfilação da Expressão Gênica , Proteínas de Insetos/genética , Masculino , Filogenia , Receptores Odorantes , Chá , Transcriptoma
5.
Ecotoxicol Environ Saf ; 202: 110914, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800249

RESUMO

Bombyx mori(Linnaeus, 1758) is an important economical insect, and the sericulture is a flourishing industry in many developing countries. Pyriproxyfen, a juvenile hormone pesticide, is often applied to cultivations widely in the world, and its exposure often resulted in silk yield reduction and non-cocooning. However, the effect of pyriproxyfen exposure on cocooning and gene expression level in the silk gland of B. mori has not been studied yet, and this study focused on the above issues. The result indicated that pyriproxyfen exposure can lead to silk gland injury, reduction of silk yield and cocooning rate. Furthermore, the expression levels of silk protein synthesis related genes were down regulated significantly. The same change trends were shown between PI3K/Akt and CncC/Keap1 pathway, which is the expressions of key genes can be elevated by pyriproxyfen exposure. In addition, the activity of detoxification enzymes (P450, GST and CarE) and the expression levels of detoxification genes were elevated after pyriproxyfen exposure, suggesting that detoxification enzymes may play an important role in detoxification of pyriproxyfen in silk gland. These results provided possible clues to the silk gland injury and gene transcriptional level changes in silkworm after pyriproxyfen exposure.


Assuntos
Bombyx/fisiologia , Inseticidas/toxicidade , Piridinas/toxicidade , Animais , Bombyx/efeitos dos fármacos , Bombyx/genética , Regulação para Baixo , Proteínas de Insetos/genética , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Larva/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Biossíntese de Proteínas , Seda/biossíntese , Seda/genética , Seda/metabolismo
6.
PLoS Pathog ; 16(8): e1008697, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776976

RESUMO

The diamondback moth, Plutella xylostella, is a cosmopolitan pest and the first species to develop field resistance to toxins from the gram-positive bacterium Bacillus thuringiensis (Bt). Although previous work has suggested that mutations of ATP-binding cassette transporter subfamily C2 (ABCC2) or C3 (ABCC3) genes can confer Cry1Ac resistance, here we reveal that P. xylostella requires combined mutations in both PxABCC2 and PxABCC3 to achieve high-level Cry1Ac resistance, rather than simply a mutation of either gene. We identified natural mutations of PxABCC2 and PxABCC3 that concurrently occurred in a Cry1Ac-resistant strain (Cry1S1000) of P. xylostella, with a mutation (RA2) causing the mis-splicing of PxABCC2 and another mutation (RA3) leading to the premature termination of PxABCC3. Genetic linkage analysis showed that RA2 and RA3 were tightly linked to Cry1Ac resistance. Introgression of RA2 and RA3 enabled a susceptible strain (G88) of P. xylostella to obtain high resistance to Cry1Ac, confirming that these genes confer resistance. To further support the role of PxABCC2 and PxABCC3 in Cry1Ac resistance, frameshift mutations were introduced into PxABCC2 and PxABCC3 singly and in combination in the G88 strain with CRISPR/Cas9 mediated mutagenesis. Bioassays of CRISPR-based mutant strains, plus genetic complementation tests, demonstrated that the deletion of PxABCC2 or PxABCC3 alone provided < 4-fold tolerance to Cry1Ac, while disruption of both genes together conferred >8,000-fold resistance to Cry1Ac, suggesting the redundant/complementary roles of PxABCC2 and PxABCC3. This work advances our understanding of Bt resistance in P. xylostella by demonstrating mutations within both PxABCC2 and PxABCC3 genes are required for high-level Cry1Ac resistance.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Bactérias/farmacologia , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Proteínas de Insetos/metabolismo , Resistência a Inseticidas , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/genética , Sequência de Aminoácidos , Animais , Bacillus thuringiensis , Proteínas de Insetos/química , Proteínas de Insetos/genética , Mariposas/química , Mariposas/genética , Mariposas/metabolismo , Mutação , Alinhamento de Sequência
7.
PLoS Pathog ; 16(8): e1008710, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32817722

RESUMO

Rice stripe virus (RSV, genus Tenuivirus, family Phenuiviridae) is the causal agent of rice stripe disease transmitted by the small brown planthopper (SBPH, Laodelphax striatellus) in a persistent propagative manner. The midgut and salivary glands of SBPH are the first and last barriers to the viral circulation and transmission processes, respectively; however, the precise mechanisms used by RSV to cross these organs and transmit to rice plants have not been fully elucidated. We obtained the full-length cDNA sequence of L. striatellus α-tubulin 2 (LsTUB) and found that RSV infection increased the level of LsTUB in vivo. Furthermore, LsTUB was shown to co-localize with RSV nonstructural protein 3 (NS3) in vivo and bound NS3 at positions 74-76 and 80-82 in vitro. Transient gene silencing of LsTUB expression caused a significant reduction in detectable RSV loads and viral NS3 expression levels, but had no effect on NS3 silencing suppressor activity and viral replication in insect cells. However, suppression of LsTUB attenuated viral spread in the bodies of SBPHs and decreased RSV transmission rates to rice plants. Electrical penetration graphs (EPG) showed that LsTUB knockdown by RNAi did not impact SBPH feeding; therefore, the reduction in RSV transmission rates was likely caused by a decrease in viral loads inside the planthopper. These findings suggest that LsTUB mediates the passage of RSV through midgut and salivary glands and leads to successful horizontal transmission.


Assuntos
Hemípteros/metabolismo , Proteínas de Insetos/metabolismo , Insetos Vetores/metabolismo , Oryza/virologia , Doenças das Plantas/virologia , Tenuivirus/fisiologia , Tubulina (Proteína)/metabolismo , Animais , Sistema Digestório/metabolismo , Sistema Digestório/virologia , Hemípteros/genética , Hemípteros/virologia , Proteínas de Insetos/genética , Insetos Vetores/genética , Insetos Vetores/virologia , Glândulas Salivares/metabolismo , Glândulas Salivares/virologia , Tubulina (Proteína)/genética
8.
PLoS One ; 15(8): e0235930, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32750054

RESUMO

Circadian clocks control rhythms in physiology and behavior entrained to 24 h light-dark cycles. Despite of conserved general schemes, molecular circadian clockworks differ between insect species. With RNA interference (RNAi) we examined an ancient circadian clockwork in a basic insect, the hemimetabolous Madeira cockroach Rhyparobia maderae. With injections of double-stranded RNA (dsRNA) of cockroach period (Rm´per), timeless 1 (Rm´tim1), or cryptochrome 2 (Rm´cry2) we searched for essential components of the clock´s core negative feedback loop. Single injections of dsRNA of each clock gene into adult cockroaches successfully and permanently knocked down respective mRNA levels within ~two weeks deleting daytime-dependent mRNA rhythms for Rm´per and Rm´cry2. Rm´perRNAi or Rm´cry2RNAi affected total mRNA levels of both genes, while Rm´tim1 transcription was independent of both, also keeping rhythmic expression. Unexpectedly, circadian locomotor activity of most cockroaches remained rhythmic for each clock gene knockdown employed. It expressed weakened rhythms and unchanged periods for Rm´perRNAi and shorter periods for Rm´tim1RNAi and Rm´cry2RNAi.As a hypothesis of the cockroach´s molecular clockwork, a basic network of switched differential equations was developed to model the oscillatory behavior of clock cells expressing respective clock genes. Data were consistent with two synchronized main groups of coupled oscillator cells, a leading (morning) oscillator, or a lagging (evening) oscillator that couple via mutual inhibition. The morning oscillators express shorter, the evening oscillators longer endogenous periods based on core feedback loops with either PER, TIM1, or CRY2/PER complexes as dominant negative feedback of the clockwork. We hypothesize that dominant morning oscillator cells with shorter periods express PER, but not CRY2, or TIM1 as suppressor of clock gene expression, while two groups of evening oscillator cells with longer periods either comprise TIM1 or CRY2/PER suppressing complexes. Modelling suggests that there is an additional negative feedback next to Rm´PER in cockroach morning oscillator cells.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Baratas/fisiologia , Criptocromos/metabolismo , Proteínas de Insetos/metabolismo , Proteínas Circadianas Period/metabolismo , Animais , Proteínas de Ciclo Celular/genética , Relógios Circadianos , Ritmo Circadiano , Baratas/genética , Criptocromos/genética , Proteínas de Insetos/genética , Masculino , Proteínas Circadianas Period/genética , Fotoperíodo , Interferência de RNA
9.
PLoS One ; 15(8): e0235912, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32776931

RESUMO

Small heat shock proteins (sHsps) function in the response of insects to abiotic stress; however, their role in response to biotic stress has been under-investigated. Mythimna separata, the oriental armyworm, is polyphenetic and exhibits gregarious and solitary phases in response to high and low population density, respectively. In this study, three genes were identified encoding sHsps, namely MsHsp19.7, MsHsp19.8 and MsHsp21.4, and expression levels in solitary and gregarious M. separata were compared. The deduced protein sequences of the three MsHsps had molecular weights of 19.7, 19.8 and 21.4 kDa, respectively, and contained a conserved α-crystalline domain. Real-time PCR analyses revealed that the three sHsps were transcribed in all developmental stages and were dramatically up-regulated at the 6th larval stage in gregarious individuals. Expression of the three MsHsps was variable in different tissues of 6th instar larvae, but exhibited consistent up- and down-regulation in the hindgut and Malpighian tubules of gregarious individuals, respectively. In addition, MsHsp19.7 and MsHsp19.8 were significantly induced when solitary forms were subjected to crowding for 36 h, but all three MsHsps were down-regulated when gregarious forms were isolated. Our findings suggest that population density functions as a stress factor and impacts MsHsps expression in M. separata.


Assuntos
Proteínas de Choque Térmico Pequenas/genética , Proteínas de Insetos/genética , Mariposas/genética , Animais , Aglomeração , Regulação da Expressão Gênica , Larva/genética , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento
10.
PLoS Pathog ; 16(8): e1008754, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776975

RESUMO

Arbovirus infection of Aedes aegypti salivary glands (SGs) determines transmission. However, there is a dearth of knowledge on SG immunity. Here, we characterized SG immune response to dengue, Zika and chikungunya viruses using high-throughput transcriptomics. We also describe a transcriptomic response associated to apoptosis, blood-feeding and lipid metabolism. The three viruses differentially regulate components of Toll, Immune deficiency (IMD) and c-Jun N- terminal Kinase (JNK) pathways. However, silencing of the Toll and IMD pathway components showed variable effects on SG infection by each virus. In contrast, regulation of the JNK pathway produced consistent responses in both SGs and midgut. Infection by the three viruses increased with depletion of the activator Kayak and decreased with depletion of the negative regulator Puckered. Virus-induced JNK pathway regulates the complement factor, Thioester containing protein-20 (TEP20), and the apoptosis activator, Dronc, in SGs. Individual and co-silencing of these genes demonstrate their antiviral effects and that both may function together. Co-silencing either TEP20 or Dronc with Puckered annihilates JNK pathway antiviral effect. Upon infection in SGs, TEP20 induces antimicrobial peptides (AMPs), while Dronc is required for apoptosis independently of TEP20. In conclusion, we revealed the broad antiviral function of JNK pathway in SGs and showed that it is mediated by a TEP20 complement and Dronc-induced apoptosis response. These results expand our understanding of the immune arsenal that blocks arbovirus transmission.


Assuntos
Aedes/imunologia , Apoptose , Febre de Chikungunya/imunologia , Proteínas do Sistema Complemento/imunologia , Dengue/imunologia , Sistema de Sinalização das MAP Quinases , Glândulas Salivares/imunologia , Infecção por Zika virus/imunologia , Aedes/virologia , Animais , Febre de Chikungunya/metabolismo , Febre de Chikungunya/prevenção & controle , Febre de Chikungunya/virologia , Vírus Chikungunya/imunologia , Proteínas do Sistema Complemento/metabolismo , Dengue/metabolismo , Dengue/prevenção & controle , Dengue/virologia , Vírus da Dengue/imunologia , Feminino , Interações Hospedeiro-Patógeno , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Insetos Vetores/imunologia , Insetos Vetores/virologia , Glândulas Salivares/virologia , Transcriptoma , Replicação Viral , Zika virus/imunologia , Infecção por Zika virus/metabolismo , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/virologia
11.
PLoS One ; 15(8): e0237134, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764791

RESUMO

Olfaction plays vital roles in the survival and reproduction of insects. The completion of olfactory recognition requires the participation of various complex protein families. However, little is known about the olfactory-related proteins in Semiothisa cinerearia Bremer et Grey, an important pest of Chinese scholar tree. In this study, we sequenced the antennal transcriptome of S. cinerearia and identified 125 olfactory-related genes, including 25 odorant-binding proteins (OBPs), 15 chemosensory proteins (CSPs), two sensory neuron membrane proteins (SNMPs), 52 odorant receptors (ORs), eight gustatory receptors (GRs) and 23 ionotropic receptors (IRs). BLASTX best hit results and phylogenetic analyses indicated that these genes were most identical to their respective orthologs from Ectropis obliqua. Further quantitative real-time PCR (qRT-PCR) analysis revealed that three ScinOBPs and three ScinORs were highly expressed in male antennae, while seven ScinOBPs and twelve ScinORs were female-specifically expressed. Our study will be useful for the elucidation of olfactory mechanisms in S. cinerearia.


Assuntos
Antenas de Artrópodes/metabolismo , Proteínas de Insetos/metabolismo , Mariposas/fisiologia , Olfato/fisiologia , Animais , Antenas de Artrópodes/citologia , Feminino , Proteínas de Insetos/genética , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Odorantes , Neurônios Receptores Olfatórios/metabolismo , Filogenia , RNA-Seq , Receptores Ionotrópicos de Glutamato/genética , Receptores Ionotrópicos de Glutamato/metabolismo , Receptores Odorantes/genética , Receptores Odorantes/metabolismo
12.
PLoS One ; 15(8): e0237242, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764803

RESUMO

The egg stage is one of the most critical periods in the life history of silkworms, during which physiological processes such as sex determination, tissue organ formation and differentiation, diapause and pigmentation occur. In addition, egg color gradually emerges around 36h after oviposition. The red egg mutant rep-1, which was recently discovered in the C1(H) wild-type, C1(H) exhibits a brown egg color. In this study, the transcriptome of the eggs was analyzed 36h after oviposition. Between the rep-1 mutant and the C1(H) wild-type, 800 differentially expressed genes (DEGs) were identified, including 325 up-regulated genes and 475 down-regulated genes. These DEGs were mainly involved in biological processes (metabolic process, cellular process, biological regulation and regulation of biological process and localization), cellular components (membrane, membrane part, cell, cell part and organelle) and molecular functions (binding, catalytic activity, transporter activity, structural molecule activity and molecular transducer activity). The pathway enrichment of these DEGs was performed based on the KEGG database, and the results indicated that these DEGs were mainly involved in pathways in the following categories: metabolic pathways, longevity-regulating pathway-multiple species, protein processing in endoplasmic reticulum, peroxisome, carbon metabolism and purine metabolism. Further analysis showed that a large number of silkworm growth- and development-related genes and ommochrome synthesis- and metabolism-related genes were differentially expressed, most of which were up-regulated in the mutant. Our research findings provide new experimental evidence for research on ommochrome pigmentation and lay the foundation for further research on the mechanism of the rep-1 mutant.


Assuntos
Bombyx/genética , Ovos , Proteínas de Insetos/genética , Pigmentação , Transcriptoma , Animais , Bombyx/anatomia & histologia , Regulação para Baixo , Ovos/análise , Feminino , Perfilação da Expressão Gênica , Mutação , Oviposição , Regulação para Cima
13.
PLoS One ; 15(8): e0237744, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32841246

RESUMO

Both the Mediterranean (MED) species of the Bemisia tabaci whitefly complex and the greenhouse whitefly (Trialeurodes vaporariorum, TV) are important agricultural pests. The two species of whiteflies differ in many aspects such as morphology, geographical distribution, host plant range, plant virus transmission, and resistance to insecticides. However, the molecular basis underlying their differences remains largely unknown. In this study, we analyzed the genetic divergences between the transcriptomes of MED and TV. In total, 2,944 pairs of orthologous genes were identified. The average identity of amino acid sequences between the two species is 93.6%. The average nonsynonymous (Ka) and synonymous (Ks) substitution rates and the ratio of Ka/Ks of the orthologous genes are 0.0389, 2.23 and 0.0204, respectively. The low average Ka/Ks ratio indicates that orthologous genes tend to be under strong purified selection. The most divergent gene classes are related to the metabolisms of xenobiotics, cofactors, vitamins and amino acids, and this divergence may underlie the different biological characteristics between the two species of whiteflies. Genes of differential expression between the two species are enriched in carbohydrate metabolism and regulation of autophagy. These findings provide molecular clues to uncover the biological and molecular differences between the two species of whiteflies.


Assuntos
Produção Agrícola , Genes de Insetos/genética , Especiação Genética , Hemípteros/genética , Proteínas de Insetos/genética , Sequência de Aminoácidos/genética , Substituição de Aminoácidos/genética , Aminoácidos/metabolismo , Animais , Hemípteros/metabolismo , Proteínas de Insetos/metabolismo , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Região do Mediterrâneo , Anotação de Sequência Molecular , RNA-Seq , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Vitaminas/metabolismo , Xenobióticos/metabolismo
14.
PLoS One ; 15(8): e0235575, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32745084

RESUMO

The sugarcane borer (Diatraea saccharalis, Fabricius, 1794) is a devastating pest that causes millions of dollars of losses each year to sugarcane producers by reducing sugar and ethanol yields. The control of this pest is difficult due to its endophytic behavior and rapid development. Pest management through biotechnological approaches has emerged in recent years as an alternative to currently applied methods. Genetic information about the target pests is often required to perform biotechnology-based management. The genomic and transcriptomic data for D. saccharalis are very limited. Herein, we report a tissue-specific transcriptome of D. saccharalis larvae and a differential expression analysis highlighting the physiological characteristics of this pest in response to two different diets: sugarcane and an artificial diet. Sequencing was performed on the Illumina HiSeq 2000 platform, and a de novo assembly was generated. A total of 27,626 protein-coding unigenes were identified, among which 1,934 sequences were differentially expressed between treatments. Processes such as defence, digestion, detoxification, signaling, and transport were highly represented among the differentially expressed genes (DEGs). Furthermore, seven aminopeptidase genes were identified as candidates to encode receptors of Cry proteins, which are toxins of Bacillus thuringiensis used to control lepidopteran pests. Since plant-insect interactions have produced a considerable number of adaptive responses in hosts and herbivorous insects, the success of phytophagous insects relies on their ability to overcome challenges such as the response to plant defences and the intake of nutrients. In this study, we identified metabolic pathways and specific genes involved in these processes. Thus, our data strongly contribute to the knowledge advancement of insect transcripts, which can be a source of target genes for pest management.


Assuntos
Dieta , Mucosa Intestinal/metabolismo , Lepidópteros/genética , Transcriptoma , Aminopeptidases/genética , Aminopeptidases/metabolismo , Animais , Herbivoria/genética , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Lepidópteros/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo
15.
PLoS Negl Trop Dis ; 14(7): e0007489, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32658913

RESUMO

Phlebotomus papatasi sand flies inject their hosts with a myriad of pharmacologically active salivary proteins to assist with blood feeding and to modulate host defenses. In addition, salivary proteins can influence cutaneous leishmaniasis disease outcome, highlighting the potential of the salivary components to be used as a vaccine. Variability of vaccine targets in natural populations influences antigen choice for vaccine development. Therefore, the objective of this study was to investigate the variability in the predicted protein sequences of nine of the most abundantly expressed salivary proteins from field populations, testing the hypothesis that salivary proteins appropriate to target for vaccination strategies will be possible. PpSP12, PpSP14, PpSP28, PpSP29, PpSP30, PpSP32, PpSP36, PpSP42, and PpSP44 mature cDNAs from field collected P. papatasi from three distinct ecotopes in the Middle East and North Africa were amplified, sequenced, and in silico translated to assess the predicted amino acid variability. Two of the predicted sequences, PpSP12 and PpSP14, demonstrated low genetic variability across the three geographic isolated sand fly populations, with conserved multiple predicted MHCII epitope binding sites suggestive of their potential application in vaccination approaches. The other seven predicted salivary proteins revealed greater allelic variation across the same sand fly populations, possibly precluding their use as vaccine targets.


Assuntos
Proteínas de Insetos/genética , Insetos Vetores/genética , Phlebotomus/genética , Proteínas e Peptídeos Salivares/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Egito , Humanos , Proteínas de Insetos/imunologia , Insetos Vetores/imunologia , Jordânia , Phlebotomus/imunologia , Proteínas e Peptídeos Salivares/imunologia , Alinhamento de Sequência
16.
Proc Natl Acad Sci U S A ; 117(28): 16283-16291, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32611810

RESUMO

The difficulty of achieving robust functional expression of insect nicotinic acetylcholine receptors (nAChRs) has hampered our understanding of these important molecular targets of globally deployed neonicotinoid insecticides at a time when concerns have grown regarding the toxicity of this chemotype to insect pollinators. We show that thioredoxin-related transmembrane protein 3 (TMX3) is essential to enable robust expression in Xenopus laevis oocytes of honeybee (Apis mellifera) and bumblebee (Bombus terrestris) as well as fruit fly (Drosophila melanogaster) nAChR heteromers targeted by neonicotinoids and not hitherto robustly expressed. This has enabled the characterization of picomolar target site actions of neonicotinoids, findings important in understanding their toxicity.


Assuntos
Proteínas de Insetos/metabolismo , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Agonistas Nicotínicos/farmacologia , Receptores Nicotínicos/metabolismo , Acetilcolina/farmacologia , Animais , Abelhas/metabolismo , Relação Dose-Resposta a Droga , Drosophila melanogaster/metabolismo , Proteínas de Insetos/agonistas , Proteínas de Insetos/genética , Oócitos/metabolismo , Subunidades Proteicas/antagonistas & inibidores , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Receptores Nicotínicos/genética , Tiorredoxinas/genética , Tiorredoxinas/metabolismo , Xenopus laevis
17.
Proc Natl Acad Sci U S A ; 117(28): 16438-16447, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601213

RESUMO

Chemosensory communication is essential to insect biology, playing indispensable roles during mate-finding, foraging, and oviposition behaviors. These traits are particularly important during speciation, where chemical perception may serve to establish species barriers. However, identifying genes associated with such complex behavioral traits remains a significant challenge. Through a combination of transcriptomic and genomic approaches, we characterize the genetic architecture of chemoperception and the role of chemosensing during speciation for a young species pair of Heliconius butterflies, Heliconius melpomene and Heliconius cydno We provide a detailed description of chemosensory gene-expression profiles as they relate to sensory tissue (antennae, legs, and mouthparts), sex (male and female), and life stage (unmated and mated female butterflies). Our results untangle the potential role of chemical communication in establishing barriers during speciation and identify strong candidate genes for mate and host plant choice behaviors. Of the 252 chemosensory genes, HmOBP20 (involved in volatile detection) and HmGr56 (a putative synephrine-related receptor) emerge as strong candidates for divergence in pheromone detection and host plant discrimination, respectively. These two genes are not physically linked to wing-color pattern loci or other genomic regions associated with visual mate preference. Altogether, our results provide evidence for chemosensory divergence between H. melpomene and H. cydno, two rarely hybridizing butterflies with distinct mate and host plant preferences, a finding that supports a polygenic architecture of species boundaries.


Assuntos
Borboletas/genética , Evolução Molecular , Especiação Genética , Proteínas de Insetos/genética , Animais , Borboletas/classificação , Borboletas/fisiologia , Quimiotaxia , Feminino , Proteínas de Insetos/metabolismo , Masculino , Fenótipo , Sensação
18.
Proc Natl Acad Sci U S A ; 117(32): 19209-19220, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32723826

RESUMO

Some organisms have evolved a survival strategy to withstand severe dehydration in an ametabolic state, called anhydrobiosis. The only known example of anhydrobiosis among insects is observed in larvae of the chironomid Polypedilum vanderplanki Recent studies have led to a better understanding of the molecular mechanisms underlying anhydrobiosis and the action of specific protective proteins. However, gene regulation alone cannot explain the rapid biochemical reactions and independent metabolic changes that are expected to sustain anhydrobiosis. For this reason, we conducted a comprehensive comparative metabolome-transcriptome analysis in the larvae. We showed that anhydrobiotic larvae adopt a unique metabolic strategy to cope with complete desiccation and, in particular, to allow recovery after rehydration. We argue that trehalose, previously known for its anhydroprotective properties, plays additional vital roles, providing both the principal source of energy and also the restoration of antioxidant potential via the pentose phosphate pathway during the early stages of rehydration. Thus, larval viability might be directly dependent on the total amount of carbohydrate (glycogen and trehalose). Furthermore, in the anhydrobiotic state, energy is stored as accumulated citrate and adenosine monophosphate, allowing rapid reactivation of the citric acid cycle and mitochondrial activity immediately after rehydration, before glycolysis is fully functional. Other specific adaptations to desiccation include potential antioxidants (e.g., ophthalmic acid) and measures to avoid the accumulation of toxic waste metabolites by converting these to stable and inert counterparts (e.g., xanthurenic acid and allantoin). Finally, we confirmed that these metabolic adaptations correlate with unique organization and expression of the corresponding enzyme genes.


Assuntos
Dípteros/metabolismo , Proteínas de Insetos/metabolismo , Monofosfato de Adenosina/metabolismo , Animais , Dessecação , Dípteros/química , Dípteros/genética , Secas , Glicogênio/genética , Glicogênio/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/genética , Larva/química , Larva/genética , Larva/metabolismo , Metaboloma , Transcriptoma , Trealose/metabolismo , Água/metabolismo
19.
Proc Natl Acad Sci U S A ; 117(29): 16928-16937, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32636269

RESUMO

Whereas most of the arthropod-borne animal viruses replicate in their vectors, this is less common for plant viruses. So far, only some plant RNA viruses have been demonstrated to replicate in insect vectors and plant hosts. How plant viruses evolved to replicate in the animal kingdom remains largely unknown. Geminiviruses comprise a large family of plant-infecting, single-stranded DNA viruses that cause serious crop losses worldwide. Here, we report evidence and insight into the replication of the geminivirus tomato yellow leaf curl virus (TYLCV) in the whitefly (Bemisia tabaci) vector and that replication is mainly in the salivary glands. We found that TYLCV induces DNA synthesis machinery, proliferating cell nuclear antigen (PCNA) and DNA polymerase δ (Polδ), to establish a replication-competent environment in whiteflies. TYLCV replication-associated protein (Rep) interacts with whitefly PCNA, which recruits DNA Polδ for virus replication. In contrast, another geminivirus, papaya leaf curl China virus (PaLCuCNV), does not replicate in the whitefly vector. PaLCuCNV does not induce DNA-synthesis machinery, and the Rep does not interact with whitefly PCNA. Our findings reveal important mechanisms by which a plant DNA virus replicates across the kingdom barrier in an insect and may help to explain the global spread of this devastating pathogen.


Assuntos
Begomovirus/fisiologia , DNA Polimerase III/metabolismo , Hemípteros/virologia , Proteínas de Insetos/metabolismo , Insetos Vetores/virologia , Replicação Viral , Animais , Begomovirus/genética , DNA Polimerase III/genética , Gossypium/parasitologia , Gossypium/virologia , Hemípteros/patogenicidade , Interações Hospedeiro-Patógeno , Proteínas de Insetos/genética , Insetos Vetores/patogenicidade , Glândulas Salivares/metabolismo , Glândulas Salivares/virologia
20.
PLoS One ; 15(7): e0235984, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32658920

RESUMO

The stalk-eyed flies (Diopsidae, Diptera) are a family of approximately 100 species of calypterate dipterans, characterised by extended head capsules. Species within the family have previously been shown to possess six subfamilies of mariner transposons, with nucleotide substitution patterns suggesting that at least two subfamilies are currently active. The vertumnana subfamily has been shown to have been involved in a horizontal transfer event involving Diopsidae and a second dipteran family in the Tephritidae. Presented here are cloned and sequenced mariner elements from three further diopsid species, in addition to a bioinformatic analysis of mariner elements identified in transcriptomic and genomic data from the genus Teleopsis. The newly identified mariner elements predominantly fall into previously recognised subfamilies, however the publicly available Teleopsis data also revealed a novel subfamily. Three of the seven identified subfamilies are shown to have undergone horizontal transfer, two of which appear to involve diopsid donor species. One recipient group of a diopsid mariner is the Bactrocera genus of tephritid flies, the transfer of which was previously proposed in an earlier study of diopsid mariner elements. The second horizontal transfer, of the mauritiana subfamily, can be traced from the Teleopsis genus to the cnidarian Hydra vulgaris. The mauritiana elements are shown to be active in the recipient H. vulgaris and transposase expression is observed in all body tissues examined in both species. The increased diversity of diopsid mariner elements points to a minimum of four subfamilies being present in the ancestral genome. Both vertical inheritance and stochastic loss of TEs have subsequently occurred within the diopsid radiation. The TE complement of H. vulgaris contains at least two mariner subfamilies of insect origin. Despite the phylogenetic distance between donor and recipient species, both subfamilies are shown to be active and proliferating within H. vulgaris.


Assuntos
Elementos de DNA Transponíveis , Dípteros/genética , Evolução Molecular , Transferência Genética Horizontal , Genoma , Interações Hospedeiro-Patógeno/genética , Proteínas de Insetos/genética , Animais , Dípteros/classificação , Olho/anatomia & histologia , Olho/crescimento & desenvolvimento , Olho/metabolismo , Hydra/fisiologia , Filogenia
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