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1.
Cell ; 143(6): 1018-29, 2010 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-21145465

RESUMEN

The emerging discoveries on the link between polyadenylation and disease states underline the need to fully characterize genome-wide polyadenylation states. Here, we report comprehensive maps of global polyadenylation events in human and yeast generated using refinements to the Direct RNA Sequencing technology. This direct approach provides a quantitative view of genome-wide polyadenylation states in a strand-specific manner and requires only attomole RNA quantities. The polyadenylation profiles revealed an abundance of unannotated polyadenylation sites, alternative polyadenylation patterns, and regulatory element-associated poly(A)(+) RNAs. We observed differences in sequence composition surrounding canonical and noncanonical human polyadenylation sites, suggesting novel noncoding RNA-specific polyadenylation mechanisms in humans. Furthermore, we observed the correlation level between sense and antisense transcripts to depend on gene expression levels, supporting the view that overlapping transcription from opposite strands may play a regulatory role. Our data provide a comprehensive view of the polyadenylation state and overlapping transcription.


Asunto(s)
Perfilación de la Expresión Génica , Hígado/metabolismo , Poli A/análisis , Análisis de Secuencia de ARN/métodos , Humanos , Poliadenilación , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
2.
Plant Biotechnol J ; 18(9): 1925-1932, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32012433

RESUMEN

The cotton bollworm, Helicoverpa armigera, is a major insect pest for a wide range of agricultural crops. It causes significant yield loss through feeding damage and by increasing the crop's vulnerability to bacterial and fungal infections. Although expression of Bacillus thuringiensis (Bt) toxins in transgenic crops has been very successful in protecting against insect pests, including H. armigera, field-evolved resistance has occurred in multiple species. To manage resistant populations, new protection strategies must be continuously developed. Trans-kingdom RNA interference (TK-RNAi) is a promising method for controlling herbivorous pests. TK-RNAi is based on delivering dsRNA or hairpin RNA containing essential insect gene sequences to the feeding insect. The ingested molecules are processed by the insect's RNAi machinery and guide it to silence the target genes. Recently, TK-RNAi delivery has been enhanced by expressing the ds- or hpRNAs in the chloroplast. This compartmentalizes the duplexed RNA away from the plant's RNAi machinery, ensuring that it is delivered in an unprocessed form to the insect. Here, we report another alternative approach for delivering precursor anti-insect RNA in plants. Insect pre-microRNA (pre-miR) transcripts were modified to contain artificial microRNAs (amiRs), targeting insect genes, and expressed in transgenic Nicotiana benthamiana plants. These modified pre-miRs remained largely unprocessed in the plants, and H. armigera feeding on leaves from these plants had increased mortality, developmental abnormalities and delayed growth rates. This shows that plant-expressed insect pre-amiRs (plin-amiRs) are a new strategy of protecting plants against herbivorous insects.


Asunto(s)
Bacillus thuringiensis , MicroARNs , Mariposas Nocturnas , Animales , Insectos , MicroARNs/genética , Mariposas Nocturnas/genética , Plantas Modificadas Genéticamente/genética , Interferencia de ARN
3.
Pestic Biochem Physiol ; 151: 25-31, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30704709

RESUMEN

RNA interference (RNAi) is becoming a practical tool to control insect pests. Many mysteries of how double-stranded RNA (dsRNA) is transported into, within, and between cells to generate an efficient RNAi response in insects are still to be unraveled. This review provides an overview of the evidence that supports a key role of endocytosis in the uptake of dsRNA on both cellular and tissue levels. Additionally, other components of cellular membrane transport and their impact on the efficiency of RNAi in insects are explored. It is now evident that the membrane transport and potentially dsRNA release from the endosome may comprise some of the limiting factors in insects that are recalcitrant to dsRNA. This review concludes with the apparent connection between gene products that are necessary for cellular trafficking of dsRNA and highly lethal RNAi targets.


Asunto(s)
Insectos/genética , Interferencia de ARN/fisiología , ARN Bicatenario/genética , Animales , Transporte Biológico/genética , Transporte Biológico/fisiología , Endocitosis/genética , Endocitosis/fisiología , Proteínas de Insectos/genética
4.
Pestic Biochem Physiol ; 150: 66-70, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30195389

RESUMEN

RNA interference (RNAi) has proven effective for controlling pest insects such as western corn rootworm (WCR), Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). Previous studies have shown that WCR adults display a robust RNAi response to orally-administered double-stranded RNA (dsRNA). However, it is unclear how quickly the response occurs after ingestion or how long RNAi effect lasts after WCR stop ingesting diet containing dsRNA. In the current study, WCR adult females were provided with diet treated with dsRNAs of Laccase 2 and Argonaute 2, two nonessential genes, for 8 days. RNAi response in WCR females commenced as early as 10 h after exposure to dsRNA and lasted up to 40 days after exposure to dsRNA ended. Our results show that dsRNA-mediated RNAi response in WCR females is rapid and long-lasting. These findings suggest that even a short-term ingestion of transgenic plants expressing dsRNA by WCR may have a sustained impact on this insect.


Asunto(s)
Escarabajos/genética , Interferencia de ARN , ARN Bicatenario/administración & dosificación , Animales , Proteínas Argonautas/genética , Femenino , Técnicas de Silenciamiento del Gen , Silenciador del Gen , Proteínas de Insectos/metabolismo , Lacasa/genética , Control Biológico de Vectores , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
5.
Pestic Biochem Physiol ; 148: 103-110, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29891360

RESUMEN

The use of transgenic crops that induce silencing of essential genes using double-stranded RNA (dsRNA) through RNA interference (RNAi) in western corn rootworm, Diabrotica virgifera virgifera, is likely to be an important component of new technologies for the control of this important corn pest. Previous studies have demonstrated that the dsRNA response in D. v. virgifera depends on the presence of RNAi pathway genes including Dicer-2 and Argonaute 2, and that downregulation of these genes limits the lethality of environmental dsRNA. A potential resistance mechanism to lethal dsRNA may involve loss of function of RNAi pathway genes. Howver, the potential for resistance to evolve may depend on whether these pathway genes have essential functions such that the loss of function of core proteins in the RNAi pathway will have fitness costs in D. v. virgifera. Fitness costs associated with potential resistance mechanisms have a central role in determining how resistance can evolve to RNAi technologies in western corn rootworm. We evaluated the effect of dsRNA and microRNA pathway gene knockdown on the development of D. v. virgifera larvae through short-term and long-term exposures to dsRNA for Dicer and Argonaute genes. Downregulation of Argonaute 2, Dicer-2, Dicer-1 did not significantly affect larval survivorship or development through short and long-term exposure to dsRNA. However, downregulation of Argonaute 1 reduced larval survivorship and delayed development. The implications of these results as they relate to D. v. virgifera resistance to lethal dsRNA are discussed.


Asunto(s)
Proteínas Argonautas/genética , Escarabajos/genética , Técnicas de Silenciamiento del Gen , Genes de Insecto , ARN Helicasas/genética , Interferencia de ARN , ARN Bicatenario/genética , Ribonucleasa III/genética , Animales , Escarabajos/crecimiento & desarrollo , Escarabajos/fisiología , Productos Agrícolas/genética , Productos Agrícolas/parasitología , Regulación hacia Abajo , Larva/genética , Larva/crecimiento & desarrollo , MicroARNs/genética , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/parasitología
6.
RNA Biol ; 13(7): 656-69, 2016 07 02.
Artículo en Inglés | MEDLINE | ID: mdl-27245473

RESUMEN

RNA interference (RNAi) has become a widely used reverse genetic tool to study gene function in eukaryotic organisms and is being developed as a technology for insect pest management. The efficiency of RNAi varies among organisms. Insects from different orders also display differential efficiency of RNAi, ranging from highly efficient (coleopterans) to very low efficient (lepidopterans). We investigated the reasons for varying RNAi efficiency between lepidopteran and coleopteran cell lines and also between the Colorado potato beetle, Leptinotarsa decemlineata and tobacco budworm, Heliothis virescens. The dsRNA either injected or fed was degraded faster in H. virescens than in L. decemlineata. Both lepidopteran and coleopteran cell lines and tissues efficiently took up the dsRNA. Interestingly, the dsRNA administered to coleopteran cell lines and tissues was taken up and processed to siRNA whereas the dsRNA was taken up by lepidopteran cell lines and tissues but no siRNA was detected in the total RNA isolated from these cell lines and tissues. The data included in this paper showed that the degradation and intracellular transport of dsRNA are the major factors responsible for reduced RNAi efficiency in lepidopteran insects.


Asunto(s)
Interferencia de ARN/fisiología , ARN Bicatenario/metabolismo , Animales , Transporte Biológico Activo/fisiología , Escarabajos , ARN Bicatenario/genética , Células Sf9 , Spodoptera
7.
Mol Immunol ; 161: 25-32, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37481826

RESUMEN

Uncontrolled activation of the alternative pathway (AP) of complement, due to genetic and/or acquired defects, plays a primary pathogenetic role in C3 glomerulopathy (C3G), a rare and heterogeneous disease characterised by predominant C3 fragment deposition within the glomerulus, as well as glomerular damage. There are currently no approved disease-specific treatments for C3G, but new drugs that directly counteract AP dysregulation, targeting components of the pathway, have opened promising new perspectives for managing the disease. Complement factor B (FB), which is primarily synthesised by hepatocytes, is a key component of the AP, as it drives the central amplification loop of the complement system. In this study we used a GalNAc (N-Acetylgalactosamine)-conjugated siRNA to selectively target and suppress liver FB expression in two mouse models characterised by the complete (Cfh-/- mice) or partial (Cfh+/-) loss of function of complement factor H (FH). Homozygous deletion of FH induced a severe C3G phenotype, with strong dysregulation of the AP of complement, glomerular C3 deposition and almost complete C3 consumption. Mice with a heterozygous deletion of FH had intermediate C3 levels and exhibited slower disease progression, resembling human C3G more closely. Here we showed that FB siRNA treatment did not improve serum C3 levels, nor limit glomerular C3 deposition in Cfh-/- mice, while it did normalise circulating C3 levels, reduce glomerular C3 deposits, and limit mesangial electron-dense deposits in Cfh+/- mice. The present data provide important insights into the potential benefits and limitations of FB-targeted inhibition strategies and suggest RNA interference-mediated FB silencing in the liver as a possible therapeutic approach for treating C3G patients with FH haploinsufficiency.


Asunto(s)
Glomerulonefritis Membranoproliferativa , Enfermedades Renales , Humanos , Animales , Ratones , Factor B del Complemento/genética , Factor B del Complemento/metabolismo , Complemento C3 , Homocigoto , Eliminación de Secuencia , Factor H de Complemento/genética , Hígado/metabolismo , Vía Alternativa del Complemento/genética , Glomerulonefritis Membranoproliferativa/genética , Glomerulonefritis Membranoproliferativa/terapia , Glomerulonefritis Membranoproliferativa/metabolismo
8.
Dev Dyn ; 239(2): 559-73, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20014104

RESUMEN

Engulfment of apoptotic cells by phagocytosis ensures the removal of unwanted and defective cells. We developed a genetically encoded marker for cell engulfment, pHMA, which consists of the pH-Sensitive derivative of GFP, pHluorin, fused to the actin-binding domain of Moesin. In healthy cells of Drosophila embryos and cultured cells, pHMA resides at the cell cortex. In dying cells, pHMA loses its cortical localization and reports a modest decrease in pH. In embryos, the dying cells lose their apical contacts, then move basally and are ultimately engulfed by neighboring cells or macrophages. The cell corpse material is strongly acidified soon after engulfment and persists in the phagocytic cell for several hours. Changes in the pHMA signal correlate well with increases or decreases in apoptosis. These data show that pHMA is a useful reporter for cell engulfment and can be used in screening for mutations that affect cell engulfment.


Asunto(s)
Apoptosis , Genes Reporteros , Proteínas Fluorescentes Verdes/metabolismo , Proteínas de Microfilamentos/metabolismo , Fagocitosis , Naranja de Acridina , Animales , Autofagia , Línea Celular , Drosophila , Proteínas Fluorescentes Verdes/genética , Concentración de Iones de Hidrógeno , Larva/metabolismo , Proteínas de Microfilamentos/genética , Dominios y Motivos de Interacción de Proteínas
9.
Genomics Proteomics Bioinformatics ; 19(5): 800-814, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-33607298

RESUMEN

Diabrotica virgifera virgifera (western corn rootworm, WCR) is one of the most destructive agricultural insect pests in North America. It is highly adaptive to environmental stimuli and crop protection technologies. However, little is known about the underlying genetic basis of WCR behavior and adaptation. More specifically, the involvement of small RNAs (sRNAs), especially microRNAs (miRNAs), a class of endogenous small non-coding RNAs that regulate various biological processes, has not been examined, and the datasets of putative sRNA sequences have not previously been generated for WCR. To achieve a comprehensive collection of sRNA transcriptomes in WCR, we constructed, sequenced, and analyzed sRNA libraries from different life stages of WCR and northern corn rootworm (NCR), and identified 101 conserved precursor miRNAs (pre-miRNAs) in WCR and other Arthropoda. We also identified 277 corn rootworm specific pre-miRNAs. Systematic analyses of sRNA populations in WCR revealed that its sRNA transcriptome, which includes PIWI-interacting RNAs (piRNAs) and miRNAs, undergoes a dynamic change throughout insect development. Phylogenetic analysis of miRNA datasets from model species reveals that a large pool of species-specific miRNAs exists in corn rootworm; these are potentially evolutionarily transient. Comparisons of WCR miRNA clusters to other insect species highlight conserved miRNA-regulated processes that are common to insects. Parallel Analysis of RNA Ends (PARE) also uncovered potential miRNA-guided cleavage sites in WCR. Overall, this study provides a new resource for studying the sRNA transcriptome and miRNA-mediated gene regulation in WCR and other Coleopteran insects.


Asunto(s)
Escarabajos , MicroARNs , Animales , Escarabajos/genética , MicroARNs/genética , Filogenia , Transcriptoma , Zea mays/genética
10.
Pest Manag Sci ; 76(4): 1500-1512, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31677217

RESUMEN

BACKGROUND: RNA interference (RNAi) triggered by maize plants expressing RNA hairpins against specific western corn rootworm (WCR) transcripts have proven to be effective at controlling this pest. To provide robust crop protection, mRNA transcripts targeted by double-stranded RNA must be sensitive to knockdown and encode essential proteins. RESULTS: Using WCR adult feeding assays, we identified Sec23 as a highly lethal RNAi target. Sec23 encodes a coatomer protein, a component of the coat protein (COPII) complex that mediates ER-Golgi transport. The lethality detected in WCR adults was also observed in early instar larvae, the life stage causing most of the crop damage, suggesting that WCR adults can serve as an alternative to larvae for dsRNA screening. Surprisingly, over 85% transcript inhibition resulted in less than 40% protein knockdown, suggesting that complete protein knockdown is not necessary for Sec23 RNAi-mediated mortality. The efficacy of Sec23 dsRNA for rootworm control was confirmed in planta; T0 maize events carrying rootworm Sec23 hairpin transgenes showed high levels of root protection in greenhouse assays. A reduction in larval survival and weight were observed in the offspring of WCR females exposed to Sec23 dsRNA LC25 in diet bioassays. CONCLUSION: We describe Sec23 as RNAi target for in planta rootworm control. High mortality in exposed adult and larvae and moderate sublethal effects in the offspring of females exposed to Sec23 dsRNA LC25 , suggest the potential for field application of this RNAi trait and the need to factor in responses to sublethal exposure into insect resistance management programs. © 2019 Society of Chemical Industry.


Asunto(s)
Zea mays , Animales , Escarabajos , Femenino , Larva , Control Biológico de Vectores , Plantas Modificadas Genéticamente , Interferencia de ARN , ARN Bicatenario
11.
Insect Biochem Mol Biol ; 104: 20-29, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30243801

RESUMEN

Western corn rootworm, Diabrotica virgifera virgifera, is the major agronomically important pest of maize in the US Corn Belt. To augment the repertoire of the available dsRNA-based traits that control rootworm, we explored a potentially haplolethal gene target, wings up A (wupA), which encodes Troponin I. Troponin I, a component of the Troponin-Tropomyosin complex, is an inhibitory protein involved in muscle contraction. In situ hybridization showed that feeding on wupA-targeted dsRNAs caused systemic transcript knockdown in D. v. virgifera larvae. The knockdown of wupA transcript, and by extension Troponin I protein, led to deterioration of the striated banding pattern in larval body muscle and decreased muscle integrity. Additionally, the loss of function of the circular muscles surrounding the alimentary system led to significant accumulation of food material in the hind gut, which is consistent with a loss of peristaltic motion of the alimentary canal. In this study, we demonstrate that wupA dsRNA is lethal in D. v. virgifera larvae when fed via artificial diet, with growth inhibition of up to 50% within two days of application. Further, wupA hairpins can be stably expressed and detected in maize. Maize expressing wupA hairpins exhibit robust root protection in greenhouse bioassays, with several maize transgene integration events showing root protection equivalent to commercial insecticidal protein-expressing maize.


Asunto(s)
Escarabajos , Raíces de Plantas/parasitología , Interferencia de ARN , Troponina I , Zea mays/parasitología , Animales , Escarabajos/genética , Escarabajos/metabolismo , Técnicas de Silenciamiento del Gen , Proteínas de Insectos/antagonistas & inhibidores , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Larva/genética , Larva/metabolismo , Troponina I/antagonistas & inhibidores , Troponina I/genética , Troponina I/metabolismo
12.
Curr Biol ; 15(17): 1548-53, 2005 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-16139209

RESUMEN

Olfactory systems confer the recognition and discrimination of a large number of structurally distinct odor molecules. Recent molecular analysis of odorant receptor (OR) genes and circuits has led to a model of odor coding in which a population of olfactory sensory neurons (OSNs) expressing a single OR converges upon a unique olfactory glomerulus. Activation of the OR can thus be read out by the activation of its cognate glomerulus. Drosophila is a powerful system in which to test this model because the entire repertoire of 62 ORs can be manipulated genetically. However, a complete understanding of how fly olfactory circuits are organized is lacking. Here, we present a nearly complete map of OR projections from OSNs to the antennal lobe (AL) in the fly brain. Four populations of OSNs coexpress two ORs along with Or83b, and a fifth expresses one OR and one gustatory receptor (GR) along with Or83b. One glomerulus receives coconvergent input from two separate populations of OSNs. Three ORs label sexually dimorphic glomeruli implicated in sexual courtship and are thus candidate Drosophila pheromone receptors. This olfactory sensory map provides an experimental framework for relating ORs to glomeruli and ultimately behavior.


Asunto(s)
Encéfalo/anatomía & histología , Drosophila , Expresión Génica , Modelos Neurológicos , Vías Olfatorias/fisiología , Neuronas Receptoras Olfatorias/metabolismo , Receptores Odorantes/metabolismo , Animales , Encéfalo/fisiología , Mapeo Encefálico , Proteínas de Drosophila/metabolismo , Neuronas Receptoras Olfatorias/citología , Receptores de Superficie Celular/metabolismo , Receptores Odorantes/genética
13.
Curr Biol ; 15(23): 2086-96, 2005 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-16332533

RESUMEN

BACKGROUND: Odorant receptors (ORs) are thought to act in a combinatorial fashion, in which odor identity is encoded by the activation of a subset of ORs and the olfactory sensory neurons (OSNs) that express them. The extent to which a single OR contributes to chemotaxis behavior is not known. We investigated this question in Drosophila larvae, which represent a powerful genetic system to analyze the contribution of individual OSNs to odor coding. RESULTS: We identify 25 larval OR genes expressed in 21 OSNs and generate genetic tools that allow us to engineer larvae missing a single OSN or having only a single or a pair of functional OSNs. Ablation of single OSNs disrupts chemotaxis behavior to a small subset of the odors tested. Larvae with only a single functional OSN are able to chemotax robustly, demonstrating that chemotaxis is possible in the absence of the remaining elements of the combinatorial code. We provide behavioral evidence that an OSN not sufficient to support chemotaxis behavior alone can act in a combinatorial fashion to enhance chemotaxis along with a second OSN. CONCLUSIONS: We conclude that there is extensive functional redundancy in the olfactory system, such that a given OSN is necessary and sufficient for the perception of only a subset of odors. This study is the first behavioral demonstration that formation of olfactory percepts involves the combinatorial integration of information transmitted by multiple ORs.


Asunto(s)
Quimiotaxis/fisiología , Drosophila/fisiología , Expresión Génica , Neuronas Receptoras Olfatorias/fisiología , Animales , Técnica del Anticuerpo Fluorescente , Ganglios de Invertebrados/citología , Ganglios de Invertebrados/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Hibridación in Situ , Larva/fisiología , Larva/ultraestructura , Microscopía Electrónica , Odorantes , Neuronas Receptoras Olfatorias/citología , Neuronas Receptoras Olfatorias/metabolismo , Regiones Promotoras Genéticas/genética , Receptores Odorantes/genética , Análisis de Regresión , Transgenes/genética
14.
Pest Manag Sci ; 74(8): 1751-1758, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29377554

RESUMEN

RNA interference (RNAi) was discovered almost 20 years ago and has been exploited worldwide to silence genes in plants and animals. A decade later, it was found that transforming plants with an RNAi construct targeting an insect gene could protect the plant against feeding by that insect. Production of double-stranded RNA (dsRNA) in a plant to affect the viability of a herbivorous animal is termed trans-kingdom RNAi (TK-RNAi). Since this pioneering work, there have been many further examples of successful TK-RNAi, but also reports of failed attempts and unrepeatable experiments. Recently, three laboratories have shown that producing dsRNA in a plant's chloroplast, rather than in its cellular cytoplasm, is a very effective way of delivering TK-RNAi. Our review examines this potentially game-changing approach and compares it with other transgenic insect-proofing schemes. © 2018 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Asunto(s)
Cloroplastos/fisiología , Genes de Insecto/genética , Control de Insectos/métodos , Plantas Modificadas Genéticamente/fisiología , Interferencia de ARN , ARN Bicatenario/genética , Animales
15.
PLoS One ; 13(8): e0201849, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30092086

RESUMEN

The cellular uptake of dsRNA after dietary exposure is critical for RNAi efficiency; however, the mechanism of its uptake in many insects remains to be understood. In this study, we evaluated the roles of the endocytic pathway genes Clathrin heavy chain (Chc), Clathrin adaptor protein AP50, ADP ribosylation factor-like 1 (Arf72A), Vacuolar H+ ATPase 16 kDa subunit (Vha16), and small GTPase Rab7 and putative sid-1-like genes (silA and silC) in RNAi response in western corn rootworm (WCR) using a two-stage dsRNA exposure bioassay. Silencing of Chc, Vha16, and AP50 led to a significant decrease in the effects of laccase2 dsRNA reporter, indicating that these genes are involved in RNAi response. However, the knockdown of either Arf72A or Rab7 did not suppress the response to laccase2 dsRNA. The silencing of the silC gene did not lead to a significant reduction in mortality or increase in the expression of V-ATPase A reporter. While the silencing of the silA gene significantly decreased insect mortality, significant changes in V-ATPase A expression were not detected. These results suggest that clathrin-dependent endocytosis is a biological mechanism that plays an important role during RNAi response in WCR adults. The fact that no definitive support for the roles of silA or silC in RNAi response was obtained support the idea that RNAi response varies greatly in different insect species, demanding additional studies focused on elucidating their involvement in this mechanism.


Asunto(s)
Clatrina/metabolismo , Escarabajos/metabolismo , Endocitosis/fisiología , Proteínas de Insectos/metabolismo , Interferencia de ARN/fisiología , Animales , Escarabajos/genética , Endocitosis/genética , Técnicas de Silenciamiento del Gen , Proteínas de Insectos/genética , Control Biológico de Vectores , ARN Bicatenario/metabolismo , Transcriptoma , Zea mays
16.
Sci Rep ; 8(1): 2061, 2018 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-29391456

RESUMEN

RNAi shows potential as an agricultural technology for insect control, yet, a relatively low number of robust lethal RNAi targets have been demonstrated to control insects of agricultural interest. In the current study, a selection of lethal RNAi target genes from the iBeetle (Tribolium castaneum) screen were used to demonstrate efficacy of orthologous targets in the economically important coleopteran pests Diabrotica virgifera virgifera and Meligethes aeneus. Transcript orthologs of 50 selected genes were analyzed in D. v. virgifera diet-based RNAi bioassays; 21 of these RNAi targets showed mortality and 36 showed growth inhibition. Low dose injection- and diet-based dsRNA assays in T. castaneum and D. v. virgifera, respectively, enabled the identification of the four highly potent RNAi target genes: Rop, dre4, ncm, and RpII140. Maize was genetically engineered to express dsRNA directed against these prioritized candidate target genes. T0 plants expressing Rop, dre4, or RpII140 RNA hairpins showed protection from D. v. virgifera larval feeding damage. dsRNA targeting Rop, dre4, ncm, and RpII140 in M. aeneus also caused high levels of mortality both by injection and feeding. In summary, high throughput systems for model organisms can be successfully used to identify potent RNA targets for difficult-to-work with agricultural insect pests.


Asunto(s)
Silenciador del Gen , Ingeniería Genética/métodos , MicroARNs/genética , Control Biológico de Vectores/métodos , Transgenes , Tribolium/genética , Animales , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Tribolium/patogenicidad , Zea mays/genética , Zea mays/parasitología
17.
PLoS One ; 12(12): e0190208, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29267401

RESUMEN

RNA interference (RNAi) based approaches can potentially be used to control insect pests. These approaches may depend on the usage of microRNA (miRNA) or double stranded RNA (dsRNA) mediated gene knockdown, which likely involves proteins that regulate these pathways, such as Argonaute 1 (Ago1), Argonaute 2 (Ago2), Dicer 1 (Dcr1), Dicer 2 (Dcr2), and Drosha in insects. We previously performed functional characterization of Ago2 and Dcr2 of western corn rootworm (WCR), Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) and observed that knockdown of Ago2 and Dcr2 ameliorated the lethal effect induced by the dsRNA-mediated knockdown of an essential gene in WCR, thereby confirming the involvement of Ago2 and Dcr2 in the dsRNA pathway. In the current study, we identified and characterized additional members of the Argonaute and Dicer gene families, namely Ago1, Ago3, Aubergine, and Dcr1, in a previously developed WCR transcriptome. We also identified a Drosha homolog in the same transcriptome. We evaluated the impacts on WCR adult fitness associated with the dsRNA-mediated knockdown of Ago1, Ago2, Dcr1, Dcr2, and Drosha genes. Among these putative RNAi pathway genes, only the knockdown of Ago1 incurred significant fitness costs such as reduced survival and oviposition rate, as well as decreased egg viability. The present study, to our knowledge, represents the first report showing that Ago1 is critical to the survival of insect adults. Our findings suggest that Ago1 plays an essential role in broader life stages of an insect than previously thought. Importantly, since fitness costs were not observed, downregulation or loss of function of RNAi pathway genes such as Ago2 or Dcr2 may confer resistance to pest control measures that rely on the normal functions of these genes. However, the precise roles of these genes under field conditions (i.e., in the presence of possible viral pathogens) requires further investigation.


Asunto(s)
Escarabajos/genética , Técnicas de Silenciamiento del Gen , Interferencia de ARN , Zea mays/parasitología , Animales , Escarabajos/fisiología , Interacciones Huésped-Parásitos , Filogenia
18.
Genes (Basel) ; 8(1)2016 Dec 24.
Artículo en Inglés | MEDLINE | ID: mdl-28029123

RESUMEN

Parental RNAi (pRNAi) is an RNA interference response where the gene knockdown phenotype is observed in the progeny of the treated organism. pRNAi has been demonstrated in female western corn rootworms (WCR) via diet applications and has been described as a potential approach for rootworm pest management. However, it is not clear if plant-expressed pRNAi can provide effective control of next generation WCR larvae in the field. In this study, we evaluated parameters required to generate a successful pRNAi response in WCR for the genes brahma and hunchback. The parameters tested included a concentration response, duration of the dsRNA exposure, timing of the dsRNA exposure with respect to the mating status in WCR females, and the effects of pRNAi on males. Results indicate that all of the above parameters affect the strength of pRNAi phenotype in females. Results are interpreted in terms of how this technology will perform in the field and the potential role for pRNAi in pest and resistance management strategies. More broadly, the described approaches enable examination of the dynamics of RNAi response in insects beyond pRNAi and crop pests.

19.
Pest Manag Sci ; 72(9): 1652-63, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27218412

RESUMEN

The western corn rootworm (WCR), Diabrotica virgifera virgifera, is the most important pest of corn in the US Corn Belt. Economic estimates indicate that costs of control and yield loss associated with WCR damage exceed $US 1 billion annually. Historically, corn rootworm management has been extremely difficult because of its ability to evolve resistance to both chemical insecticides and cultural control practices. Since 2003, the only novel commercialized developments in rootworm management have been transgenic plants expressing Bt insecticidal proteins. Four transgenic insecticidal proteins are currently registered for rootworm management, and field resistance to proteins from the Cry3 family highlights the importance of developing traits with new modes of action. One of the newest approaches for controlling rootworm pests involves RNA interference (RNAi). This review describes the current understanding of the RNAi mechanisms in WCR and the use of this technology for WCR management. Further, the review addresses ecological risk assessment of RNAi and insect resistance management of RNAi for corn rootworm. © 2016 Society of Chemical Industry.


Asunto(s)
Escarabajos , Control Biológico de Vectores/métodos , Interferencia de ARN , Animales , Escarabajos/genética , Escarabajos/crecimiento & desarrollo , Larva/genética , Larva/crecimiento & desarrollo
20.
Insect Biochem Mol Biol ; 71: 58-71, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26873291

RESUMEN

RNA interference (RNAi) is a gene silencing mechanism that is present in animals and plants and is triggered by double stranded RNA (dsRNA) or small interfering RNA (siRNA), depending on the organism. In the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), RNAi can be achieved by feeding rootworms dsRNA added to artificial diet or plant tissues transformed to express dsRNA. The effect of RNAi depends on the targeted gene function and can range from an absence of phenotypic response to readily apparent responses, including lethality. Furthermore, RNAi can directly affect individuals that consume dsRNA or the effect may be transferred to the next generation. Our previous work described the potential use of genes involved in embryonic development as a parental RNAi technology for the control of WCR. In this study, we describe the use of chromatin-remodeling ATPases as target genes to achieve parental gene silencing in two insect pests, a coleopteran, WCR, and a hemipteran, the Neotropical brown stink bug, Euschistus heros Fabricius (Hemiptera: Pentatomidae). Our results show that dsRNA targeting chromatin-remodeling ATPase transcripts, brahma, mi-2, and iswi strongly reduced the fecundity of the exposed females in both insect species. Additionally, knockdown of chd1 reduced the fecundity of E. heros.


Asunto(s)
Adenosina Trifosfatasas/genética , Cromatina/metabolismo , Escarabajos/genética , Heterópteros/genética , Proteínas de Insectos/genética , Adenosina Trifosfatasas/metabolismo , Animales , Cromatina/genética , Escarabajos/enzimología , Escarabajos/fisiología , Femenino , Fertilidad , Heterópteros/enzimología , Heterópteros/fisiología , Control de Insectos , Proteínas de Insectos/metabolismo , Masculino , Control Biológico de Vectores , Interferencia de ARN , ARN Interferente Pequeño/genética
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