The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Bernard Reynaud - One of the best experts on this subject based on the ideXlab platform.
-
Effects of temperature increase on the epidemiology of three major vector-borne viruses
European Journal of Plant Pathology, 2008Co-Authors: Bernard Reynaud, Helene Delatte, Michel Peterschmitt, Denis FargetteAbstract:The epidemiologies of Maize streak virus (MSV), Maize stripe virus (MSpV), and Maize mosaic virus (MMV) were compared in La Reunion over a three year-period. Disease incidence caused by each virus was assessed, and the leaf and planthopper vector populations (Cicadulina mbila and Peregrinus maidis) were estimated in weekly sowings of the temperate, virus-susceptible maize hybrid INRA 508 and of the composite resistant cv. IRAT 297. MSV caused the most prevalent disease and MMV the least, with lower incidences in cv. IRAT 297 than in INRA 508. For each plant–virus–vector combination, (a) disease incidence was positively correlated to vector abundance, often with 1 month of time lag; (b) annual periodicity of disease incidence and of vector numbers was consistent with highest autocorrelations and a time lag of 12 months, (c) vector numbers and disease incidence were closely associated with temperature fluctuations, both remaining relatively constant below 24°C and increasing rapidly above this threshold temperature. By contrast, relationships with rainfall and relative humidity (RH) were less consistent. Overall, 63 to 80% of the variance of disease incidence was explained through stepwise regression with vector number, temperature, and sometimes also rainfall or RH. The simple epidemiological model proposed underlines the close link between increased temperature and possible (re-) emergence of these three diseases in a maize cropping area.
-
evaluation of maize inbreds for maize stripe virus and maize mosaic virus resistance disease progress in relation to time and the cumulative number of planthoppers
Phytopathology, 2005Co-Authors: Jacques Dintinger, Frédéric Chiroleu, Nathalie Boissot, Perla Hamon, Bernard ReynaudAbstract:Dintinger, J., Boissot, N., Chiroleu, F., Hamon, P., and Reynaud, B. 2005. Evaluation of maize inbreds for Maize stripe virus and Maize mosaic virus resistance: Disease progress in relation to time and the cumulative number of planthoppers. Phytopathology 95:600-607. Five tropical maize lines were tested and compared with the susceptible control line B73 for resistance to Maize stripe virus (MStV) and Maize mosaic virus (MMV), both propagatively transmitted by the planthopper Peregrinus maidis (Homoptera: Delphacidae). Resistance to each virus was evaluated separately by artificial inoculations with planthoppers viruliferous for either one virus or the other. Disease incidence and symptom severity progression were quantified in relation to time and the cumulative number of planthoppers. Line Hi40 was found to be susceptible to MStV and highly resistant to MMV. Generally, no MMV symptoms developed on Hi40, even under intense inoculation pressure by a large number of viruliferous planthoppers. Line Rev81 showed a partial but strong resistance to MStV, which mainly reduced disease incidence. Nevertheless, this resistance to MStV was the highest ever reported and held up, even when challenged by large numbers of planthoppers. The percentage of infected plants in line Rev81 never exceeded 30 to 40% in our experiments. Moderate levels of resistance to MStV, and to a lesser extent MMV, were found in lines 37-2, A211, and Mp705. However, resistance in these lines was completely overcome using a large number of insects transmitting either of the two viruses. These results suggest that different types of resistance to MMV and MStV are available in maize lines from Caribbean and Mascarene germ plasm. The expression of virus-specific resistance identified in Hi40 and Rev81 lines was not affected by intense inoculation pressure. In contrast, the moderate resistance in 37-2, A211, and Mp705 was partially effective against both viruses but not at high inoculation pressure. These different types of resistance, when present in the same genotype, could provide protection against both viruses.
-
Feeding behaviour of the planthopper Peregrinus maidis on maize analysed by digital signal processing of EPG and MET structure of stylet pathway
2004Co-Authors: Bernard Reynaud, Daniel Gargani, Julien Lecoq, Patrick Turpin, Martial Grondin, Michel PeterschmittAbstract:Peregrinus maidis (AsmeadXHemiptera. Delphacidae) is the only known vector of Maize mosaic virus and Matze stripe virus, two circulative and propagative viruses. The feeding behaviour of P. maidis was investigated with electrical penetration graph technique (DC-EPG). Five different waveforms were characterised. Based on the correlation between waveforms and the fine structure of stylet pathways observed by transmission electron microscopy, active ingestion was restricted to xylem vessels, whereas passive ingestion and watery salivation occurred intermittently in sieve tubes. Spectral and time frequencies analysis of digital data obtained with the "'EPG-Soft" software improved the distinction between ingestion and salivation activities in sieve tubes. Ingestion and watery salivation are essential phases of the feeding behaviour of piercing sucking insects, in relation to acquisition and inoculation of circulative viruses. (Resume d'auteur)
-
etude du comportement alimentaire de Peregrinus maidis hemiptera delphacidae sur mais par electropenetrographie et microscopie electrique a transmission
9ème Rencontres de virologie végétale 2 au 6 février 2006 Aussois, 2003Co-Authors: Daniel Gargani, Jacques Dintinger, Michel Peterschmitt, Julien Lecoq, Patrick Turpin, Martial Grondin, Jeanmichel Lett, Bernard ReynaudAbstract:L'efficacite avec laquelle un virus est transmis aux plantes par son insecte vecteur depend de plusieurs parametres dont le comportement alimentaire de l'insecte. P. maidis est un delphacide vecteur en zone tropicale du Maize mosaic virus (MMV, Nucleorhabdovirus) et du Maize stripe virus (MStV, Tenuivirus) selon le mode circulant multipliant. Pour caracteriser et differencier les etapes du comportement alimentaire de P. maidis sur mais (Zea mays), nous avons utilise un systeme d'electrophysiologie nomme electropenetrographie (EPG-DC). L'EPG nous a permis de caracteriser 5 types de signaux electriques. Dans le but de correler ces signaux a des activites biologiques de l'insecte, le trajet tissulaire et cellulaire des stylets de l'insecte a ete analyse en microscopie electronique a transmission (MET) pour trois de ces signaux. La correlation entre les signaux EPG et les observations en microscopie photonique et electronique a permis d'associer certains signaux a des activites alimentaires caracteristiques: la penetration des stylets dans le limbe foliaire, l'ingestion active dans le xyleme et l'ingestion et /ou la salivation dans le phloeme. L'identification des signaux par rapport au comportement alimentaire de P. maidis permet d'utiliser les analyses EPG pour distinguer chez le mais une resistance au virus d'une resistance a la plante. Des hypotheses d'un mecanisme de resistance a la transmission des virus concernes dans des mais de genotypes differents sont envisagees. (Texte integral)
-
electrical penetration graphs from Peregrinus maidis on a susceptible maize hybrid
Entomologia Experimentalis Et Applicata, 1996Co-Authors: C. Buduca, Bernard Reynaud, Lan Sun D Luk, Frank MolinaroAbstract:Le comportement alimentaire de Peregrinus maidis (Homoptera : Delphacidae), vecteur du virus de la mosaique du mais (MMV) et du virus de la striure du mais (MSV), est etudie a partir des graphes de penetration electrique (GPE). Les differents GPE montrent 3 signaux temporaux distincts. Ces signaux (classe 1, 2 et 3) sont respectivement correles avec les coupes histologiques des activites alimentaires de sondage, d'ingestion du xyleme et du phloeme. Bien que ces signaux soient egalement decrits par plusieurs parametres statistiques, seules les classes 1 et 2 sont significativement distinctes. Cette etude demontre l'importance de ce type d'analyse dans la caracterisation et la comparaison des signaux des insectes perceurs et suceurs
Anna E. Whitfield - One of the best experts on this subject based on the ideXlab platform.
-
microinjection of corn planthopper Peregrinus maidis embryos for crispr cas9 genome editing
Journal of Visualized Experiments, 2021Co-Authors: William Klobasa, Anna E. Whitfield, Dorith Rotenberg, Fuchyun Chu, Ordom Brian Huot, Nathaniel Grubbs, Marce D LorenzenAbstract:The corn planthopper, Peregrinus maidis, is a pest of maize and a vector of several maize viruses. Previously published methods describe the triggering of RNA interference (RNAi) in P. maidis through microinjection of double-stranded RNAs (dsRNAs) into nymphs and adults. Despite the power of RNAi, phenotypes generated via this technique are transient and lack long-term Mendelian inheritance. Therefore, the P. maidis toolbox needs to be expanded to include functional genomic tools that would enable the production of stable mutant strains, opening the door for researchers to bring new control methods to bear on this economically important pest. However, unlike the dsRNAs used for RNAi, the components used in CRISPR/Cas9-based genome editing and germline transformation do not easily cross cell membranes. As a result, plasmid DNAs, RNAs, and/or proteins must be microinjected into embryos before the embryo cellularizes, making the timing of injection a critical factor for success. To that end, an agarose-based egg-lay method was developed to allow embryos to be harvested from P. maidis females at relatively short intervals. Herein are provided detailed protocols for collecting and microinjecting precellular P. maidis embryos with CRISPR components (Cas9 nuclease that has been complexed with guide RNAs), and results of Cas9-based gene knockout of a P. maidis eye-color gene, white, are presented. Although these protocols describe CRISPR/Cas9-genome editing in P. maidis, they can also be used for producing transgenic P. maidis via germline transformation by simply changing the composition of the injection solution.
-
transcriptomic response of the insect vector Peregrinus maidis to maize mosaic rhabdovirus and identification of conserved responses to propagative viruses in hopper vectors
Virology, 2017Co-Authors: Kathleen M. Martin, Dorith Rotenberg, Karen Barandocalviar, Derek J Schneweis, Catherine L Stewart, Anna E. WhitfieldAbstract:Abstract Maize mosaic virus (MMV) is a plant-pathogenic rhabdovirus that is transmitted by the corn planthopper, Peregrinus maidis , in a propagative manner. P. maidis supports long-term MMV infections with no negative effects on insect performance. To elucidate whole-body transcriptome responses to virus infection, RNA-Seq was used to examine differential gene expression of virus-infected adult insects, and libraries were prepared from replicated groups of virus-exposed insects and non-exposed insects. From the 68,003 de novo -assembled transcripts, 144 were differentially-expressed (DE) during viral infection with comparable numbers up- and down-regulated. DE transcripts with similarity to genes associated with transposable elements (i.e., RNA-directed DNA polymerases) were enriched and may represent a mechanisim for modulating virus infection. Comparison of the P. maidis DE transcripts to published propagative virus-responsive transcript databases for two other hopper vectors revealed that 16% of the DE transcripts were shared across the three systems and may represent conserved responses to propagative viruses.
-
analysis of acquisition and titer of maize mosaic rhabdovirus in its vector Peregrinus maidis hemiptera delphacidae
Journal of Insect Science, 2016Co-Authors: Karen Barandocalviar, Dorith Rotenberg, Girly M Ramirez, Anna E. WhitfieldAbstract:The corn planthopper, Peregrinus maidis (Ashmead) (Hemiptera: Delphacidae), transmits Maize mosaic rhabdovirus (MMV), an important pathogen of maize and sorghum, in a persistent propagative manner. To better understand the vectorial capacity of P. maidis , we determined the efficiency of MMV acquisition by nymphal and adult stages, and characterized MMV titer through development. Acquisition efficiency, i.e., proportion of insects that acquired the virus, was determined by reverse transcriptase polymerase chain reaction (RT-PCR) and virus titer of individual insects was estimated by quantitative RT-PCR. Acquisition efficiency of MMV differed significantly between nymphs and adults. MMV titer increased significantly over time and throughout insect development from nymphal to adult stage, indication of virus replication in the vector during development. There was a positive association between the vector developmental stage and virus titer. Also, the average titer in male insects was threefold higher than female titers, and this difference persisted up to 30 d post adult eclosion. Overall, our findings indicate that nymphs are more efficient than adults at acquiring MMV and virus accumulated in the vector over the course of nymphal development. Furthermore, sustained infection over the lifespan of P. maidis indicates a potentially high capacity of this vector to transmit MMV.
-
development of rnai methods for Peregrinus maidis the corn planthopper
PLOS ONE, 2013Co-Authors: Jianxiu Yao, Karen Barandocalviar, Dorith Rotenberg, Alireza Afsharifar, Anna E. WhitfieldAbstract:The corn planthopper, Peregrinus maidis, is a major pest of agronomically-important crops. Peregrinus maidis has a large geographical distribution and transmits Maize mosaic rhabdovirus (MMV) and Maize stripe tenuivirus (MSpV). The objective of this study was to develop effective RNAi methods for P. maidis. Vacuolar-ATPase (V-ATPase) is an essential enzyme for hydrolysis of ATP and for transport of protons out of cells thereby maintaining membrane ion balance, and it has been demonstrated to be an efficacious target for RNAi in other insects. In this study, two genes encoding subunits of P. maidis V-ATPase (V-ATPase B and V-ATPase D) were chosen as RNAi target genes. The open reading frames of V-ATPase B and D were generated and used for constructing dsRNA fragments. Experiments were conducted using oral delivery and microinjection of V-ATPase B and V-ATPase D dsRNA to investigate the effectiveness of RNAi in P. maidis. Real-time quantitative reverse transcriptase-PCR (qRT-PCR) analysis indicated that microinjection of V-ATPase dsRNA led to a minimum reduction of 27-fold in the normalized abundance of V-ATPase transcripts two days post injection, while ingestion of dsRNA resulted in a two-fold reduction after six days of feeding. While both methods of dsRNA delivery resulted in knockdown of target transcripts, the injection method was more rapid and effective. The reduction in V-ATPase transcript abundance resulted in observable phenotypes. Specifically, the development of nymphs injected with 200 ng of either V-ATPase B or D dsRNA was impaired, resulting in higher mortality and lower fecundity than control insects injected with GFP dsRNA. Microscopic examination of these insects revealed that female reproductive organs did not develop normally. The successful development of RNAi in P. maidis to target specific genes will enable the development of new insect control strategies and functional analysis of vital genes and genes associated with interactions between P. maidis and MMV.
-
analysis of expressed sequence tags from maize mosaic rhabdovirus infected gut tissues of Peregrinus maidis reveals the presence of key components of insect innate immunity
Insect Molecular Biology, 2011Co-Authors: Anna E. Whitfield, Dorith Rotenberg, V Aritua, Saskia A. HogenhoutAbstract:The corn planthopper, Peregrinus maidis, causes direct feeding damage to plants and transmits Maize mosaic rhabdovirus (MMV) in a persistent-propagative manner. MMV must cross several insect tissue layers for successful transmission to occur, and the gut serves as an important barrier for rhabdovirus transmission. In order to facilitate the identification of proteins that may interact with MMV either by facilitating acquisition or responding to virus infection, we generated and analysed the gut transcriptome of P. maidis. From two normalized cDNA libraries, we generated a P. maidis gut transcriptome composed of 20 771 expressed sequence tags (ESTs). Assembly of the sequences yielded 1860 contigs and 14 032 singletons, and biological roles were assigned to 5793 (36%). Comparison of P. maidis ESTs with other insect amino acid sequences revealed that P. maidis shares greatest sequence similarity with another hemipteran, the brown planthopper Nilaparvata lugens. We identified 202 P. maidis transcripts with putative homology to proteins associated with insect innate immunity, including those implicated in the Toll, Imd, JAK/STAT, Jnk and the small-interfering RNA-mediated pathways. Sequence comparisons between our P. maidis gut EST collection and the currently available National Center for Biotechnology Information EST database collection for Ni. lugens revealed that a pathogen recognition receptor in the Imd pathway, peptidoglycan recognition protein-long class (PGRP-LC), is present in these two members of the family Delphacidae; however, these recognition receptors are lacking in the model hemipteran Acyrthosiphon pisum. In addition, we identified sequences in the P. maidis gut transcriptome that share significant amino acid sequence similarities with the rhabdovirus receptor molecule, acetylcholine receptor (AChR), found in other hosts. This EST analysis sheds new light on immune response pathways in hemipteran guts that will be useful for further dissecting innate defence response pathways to rhabdovirus infection.
Saskia A. Hogenhout - One of the best experts on this subject based on the ideXlab platform.
-
analysis of expressed sequence tags from maize mosaic rhabdovirus infected gut tissues of Peregrinus maidis reveals the presence of key components of insect innate immunity
Insect Molecular Biology, 2011Co-Authors: Anna E. Whitfield, Dorith Rotenberg, V Aritua, Saskia A. HogenhoutAbstract:The corn planthopper, Peregrinus maidis, causes direct feeding damage to plants and transmits Maize mosaic rhabdovirus (MMV) in a persistent-propagative manner. MMV must cross several insect tissue layers for successful transmission to occur, and the gut serves as an important barrier for rhabdovirus transmission. In order to facilitate the identification of proteins that may interact with MMV either by facilitating acquisition or responding to virus infection, we generated and analysed the gut transcriptome of P. maidis. From two normalized cDNA libraries, we generated a P. maidis gut transcriptome composed of 20 771 expressed sequence tags (ESTs). Assembly of the sequences yielded 1860 contigs and 14 032 singletons, and biological roles were assigned to 5793 (36%). Comparison of P. maidis ESTs with other insect amino acid sequences revealed that P. maidis shares greatest sequence similarity with another hemipteran, the brown planthopper Nilaparvata lugens. We identified 202 P. maidis transcripts with putative homology to proteins associated with insect innate immunity, including those implicated in the Toll, Imd, JAK/STAT, Jnk and the small-interfering RNA-mediated pathways. Sequence comparisons between our P. maidis gut EST collection and the currently available National Center for Biotechnology Information EST database collection for Ni. lugens revealed that a pathogen recognition receptor in the Imd pathway, peptidoglycan recognition protein-long class (PGRP-LC), is present in these two members of the family Delphacidae; however, these recognition receptors are lacking in the model hemipteran Acyrthosiphon pisum. In addition, we identified sequences in the P. maidis gut transcriptome that share significant amino acid sequence similarities with the rhabdovirus receptor molecule, acetylcholine receptor (AChR), found in other hosts. This EST analysis sheds new light on immune response pathways in hemipteran guts that will be useful for further dissecting innate defence response pathways to rhabdovirus infection.
-
A neurotropic route for Maize mosaic virus (Rhabdoviridae) in its planthopper vector Peregrinus maidis.
Virus research, 2007Co-Authors: El-desouky Ammar, Saskia A. HogenhoutAbstract:To investigate the dissemination route of Maize mosaic virus (MMV, Rhabdoviridae) in its planthopper vector Peregrinus maidis (Delphacidae, Hemiptera), temporal and spatial distribution of MMV was studied by immunofluorescence confocal laser scanning microscopy following 1-week acquisition feeding of planthoppers on infected plants. MMV was detected 1-week post first access to diseased plants (padp) in the midgut and anterior diverticulum, 2-week padp in the esophagus, nerves, nerve ganglia and visceral muscles, and 3-week padp in hemocytes, tracheae, salivary glands and other tissues. MMV is neurotropic in P. maidis; infection was more extensive in the nervous system compared to other tissues. A significantly higher proportion of planthoppers had infected midguts (28.1%) compared to those with infected salivary glands (20.4%) or to those that transmitted MMV (15.7%), suggesting the occurrence of midgut and salivary gland barriers to MMV transmission in P. maidis. In this planthopper, the esophagus and anterior diverticulum are located between the compound ganglionic mass and the salivary glands. We postulate that MMV may overcome transmission barriers in P. maidis by proceeding from the midgut to the anterior diverticulum and esophagus, and from these to the salivary glands via the nervous system: a neurotropic route similar to that of some vertebrate-infecting rhabdoviruses.
-
Characterization of Maize Iranian mosaic virus and comparison with Hawaiian and other isolates of Maize mosaic virus (Rhabdoviridae).
Journal of Phytopathology, 2005Co-Authors: El-desouky Ammar, R. G. Gomez‐luengo, D. T. Gordon, Saskia A. HogenhoutAbstract:Maize Iranian mosaic virus (MIMV) was characterized and compared with isolates of Maize mosaic virus (MMV, genus Nucleorhabdovirus, family Rhabdoviridae) in insect transmission, cytopathology and ultrastructure of infected maize cells, virion proteins and serologically. MIMV is naturally transmitted by Ribautodelphax notabilis, a delphacid planthopper, in Iran. In this study, another planthopper, Peregrinus maidis, vector of MMV, transmitted MIMV with an estimated efficiency of 0.4–1.6% following feeding on MIMVinfected maize plants and 64% following injection of MIMV into the hemolymph, suggesting that P. maidis gut tissues largely blocked MIMV transmission. MIMV and MMV-HI (Hawaii) induced similar cytopathologies in cells of infected maize leaves, with virions budding through inner nuclear and endoplasmic reticulum membranes. In thin sections, virions of MIMV were significantly shorter than those of MMV-HI. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis of virions of MIMV, MMV-HI, MMV-CR (Costa Rica) and MMV-FL (Florida) yielded six proteins of which four were identified as the putative G, N, P and M proteins of plant rhabdoviruses. The N, P and M proteins of MIMV migrated faster in gels than those of the MMV isolates indicating a lower molecular weight, whereas the bands corresponding to the G proteins migrated similarly for both viruses. Polyclonal antibodies to MMV-HI failed to react with virions of MIMV in enzyme-linked immunosorbent assay (ELISA) and with MIMV proteins in Western blots. In contrast, these antibodies reacted strongly with MMV-HI and MMV-FL virions in ELISA and with MMV-HI, MMV-CR and MMV-FL proteins in Western blots. Further, in ELISA, polyclonal antibodies to MMV-MR (Mauritius) reacted weakly with MIMV virions but strongly with MMV-HI and MMV-FL virions. Thus, it is concluded that MIMV is a new virus of the Nucleorhabdovirus genus that may be distantly related to MMV.
H C Sharma - One of the best experts on this subject based on the ideXlab platform.
-
Host-Plant Resistance to Shoot Fly and Spotted Stem Borer in Sorghum
2015Co-Authors: H C SharmaAbstract:Nearly 150 insect species have been repor ted as pests on sorghum, of which shoot f ly (Atherigona soccata), s t em borer (Chibpar teUus) , a rmy w o r m (Mythimna separata), aphids (Rhopalosiphum maidis, Melanaphis sacchari), shoot bug (Peregrinus maidis), sorghum midge (Stenodiplosis sorghicola), head bug (Calocoris angustatus), and hea
-
Cytoplasmic male-sterility affects expression of resistance to Shoot Bug (Peregrinus maidis), Sugarcane Aphid (Melanaphis sacchari) and Spotted Stem Borer (Chilo partellus) in Sorghum
2006Co-Authors: Mukesh K. Dhillon, H C Sharma, G. Pampapathy, B V S ReddyAbstract:Discovery of cytoplasmic male-sterility (CMS) has led to large-scale exploitation of heterotic potential for increasing crop production (Kaul 1988). Most of the sorghum [Sorghum bicolor (L.) Moench] hybrids developed have been based on milo (A1) cytoplasm with only a few hybrids based on A2 cytoplasm in China (Shan et al. 2000). The A1 cytoplasm-based hybrids have been reported to be highly susceptible to insect pests (Sharma 2001; Sharma et al. 2004; Dhillon et al. 2006). Therefore, it is important to diversify the CMS systems to safeguard against outbreaks of insect pests and diseases. In addition to diversifying CMS sources, it is also important to understand the interactions between the target insect pests and hybrid parents to develop appropriate strategies for development and deployment of insect-resistant hybrids. Therefore, we examined the influence of CMS on the expression of resistance to shoot bug [Peregrinus maidis (Ashmead)], sugarcane aphid [Melanaphis sacchari (Zehntner)] and spotted stem borer [Chilo partellus (Swinhoe)] for deploying insect-resistance genes through high-yielding hybrids of sorghum for integrated pest management.
-
Techniques to Screen Sorghums for Resistance to Insect Pests
1992Co-Authors: H C Sharma, Vitthal R Bhagwat, Poluru G. PadmajaAbstract:Sorghum is an important cereal crop in Asia, Africa, Americas and Australia. Grain yields on farmers’ fi elds in Asia and Africa are generally low (500−800 kg ha-1) mainly due to insect pest damage. Nearly 150 insect species have been reported as pests on sorghum (Sharma 1993), of which sorghum shoot fl y (Atherigona soccata), stem borers (Chilo partellus, Busseola fusca, Eldana saccharina and Diatraea spp.), armyworms (Mythimna separata, Spodoptera frugiperda and S. exempta), shoot bug (Peregrinus maidis), aphids (Schizaphis graminum and Melanaphis sacchari), spider mites (Oligonychus spp.), grasshoppers and locusts (Hieroglyphus, Oedaleus, Aliopus, Schistocerca, and Locusta), sorghum midge (Stenodiplosis sorghicola), mirid head bugs (Calocoris angustatus and Eurystylus oldi), and head caterpillars (Helicoverpa, Eublemma, Cryptoblabes, Pyroderces, and Nola) are the major pests worldwide. Other insects reported to be damaging sorghum are of regional/local importance. Annual losses due to insect pests differ in magnitude on a regional basis. They have been estimated to be $1,089 million in the semi-arid tropics (SAT), $250 million in United States, and $80 million in Australia (ICRISAT 1992). In India, nearly 32% of sorghum crop is lost due to insect pests (Borad and Mittal 1983).
Dorith Rotenberg - One of the best experts on this subject based on the ideXlab platform.
-
microinjection of corn planthopper Peregrinus maidis embryos for crispr cas9 genome editing
Journal of Visualized Experiments, 2021Co-Authors: William Klobasa, Anna E. Whitfield, Dorith Rotenberg, Fuchyun Chu, Ordom Brian Huot, Nathaniel Grubbs, Marce D LorenzenAbstract:The corn planthopper, Peregrinus maidis, is a pest of maize and a vector of several maize viruses. Previously published methods describe the triggering of RNA interference (RNAi) in P. maidis through microinjection of double-stranded RNAs (dsRNAs) into nymphs and adults. Despite the power of RNAi, phenotypes generated via this technique are transient and lack long-term Mendelian inheritance. Therefore, the P. maidis toolbox needs to be expanded to include functional genomic tools that would enable the production of stable mutant strains, opening the door for researchers to bring new control methods to bear on this economically important pest. However, unlike the dsRNAs used for RNAi, the components used in CRISPR/Cas9-based genome editing and germline transformation do not easily cross cell membranes. As a result, plasmid DNAs, RNAs, and/or proteins must be microinjected into embryos before the embryo cellularizes, making the timing of injection a critical factor for success. To that end, an agarose-based egg-lay method was developed to allow embryos to be harvested from P. maidis females at relatively short intervals. Herein are provided detailed protocols for collecting and microinjecting precellular P. maidis embryos with CRISPR components (Cas9 nuclease that has been complexed with guide RNAs), and results of Cas9-based gene knockout of a P. maidis eye-color gene, white, are presented. Although these protocols describe CRISPR/Cas9-genome editing in P. maidis, they can also be used for producing transgenic P. maidis via germline transformation by simply changing the composition of the injection solution.
-
transcriptomic response of the insect vector Peregrinus maidis to maize mosaic rhabdovirus and identification of conserved responses to propagative viruses in hopper vectors
Virology, 2017Co-Authors: Kathleen M. Martin, Dorith Rotenberg, Karen Barandocalviar, Derek J Schneweis, Catherine L Stewart, Anna E. WhitfieldAbstract:Abstract Maize mosaic virus (MMV) is a plant-pathogenic rhabdovirus that is transmitted by the corn planthopper, Peregrinus maidis , in a propagative manner. P. maidis supports long-term MMV infections with no negative effects on insect performance. To elucidate whole-body transcriptome responses to virus infection, RNA-Seq was used to examine differential gene expression of virus-infected adult insects, and libraries were prepared from replicated groups of virus-exposed insects and non-exposed insects. From the 68,003 de novo -assembled transcripts, 144 were differentially-expressed (DE) during viral infection with comparable numbers up- and down-regulated. DE transcripts with similarity to genes associated with transposable elements (i.e., RNA-directed DNA polymerases) were enriched and may represent a mechanisim for modulating virus infection. Comparison of the P. maidis DE transcripts to published propagative virus-responsive transcript databases for two other hopper vectors revealed that 16% of the DE transcripts were shared across the three systems and may represent conserved responses to propagative viruses.
-
analysis of acquisition and titer of maize mosaic rhabdovirus in its vector Peregrinus maidis hemiptera delphacidae
Journal of Insect Science, 2016Co-Authors: Karen Barandocalviar, Dorith Rotenberg, Girly M Ramirez, Anna E. WhitfieldAbstract:The corn planthopper, Peregrinus maidis (Ashmead) (Hemiptera: Delphacidae), transmits Maize mosaic rhabdovirus (MMV), an important pathogen of maize and sorghum, in a persistent propagative manner. To better understand the vectorial capacity of P. maidis , we determined the efficiency of MMV acquisition by nymphal and adult stages, and characterized MMV titer through development. Acquisition efficiency, i.e., proportion of insects that acquired the virus, was determined by reverse transcriptase polymerase chain reaction (RT-PCR) and virus titer of individual insects was estimated by quantitative RT-PCR. Acquisition efficiency of MMV differed significantly between nymphs and adults. MMV titer increased significantly over time and throughout insect development from nymphal to adult stage, indication of virus replication in the vector during development. There was a positive association between the vector developmental stage and virus titer. Also, the average titer in male insects was threefold higher than female titers, and this difference persisted up to 30 d post adult eclosion. Overall, our findings indicate that nymphs are more efficient than adults at acquiring MMV and virus accumulated in the vector over the course of nymphal development. Furthermore, sustained infection over the lifespan of P. maidis indicates a potentially high capacity of this vector to transmit MMV.
-
development of rnai methods for Peregrinus maidis the corn planthopper
PLOS ONE, 2013Co-Authors: Jianxiu Yao, Karen Barandocalviar, Dorith Rotenberg, Alireza Afsharifar, Anna E. WhitfieldAbstract:The corn planthopper, Peregrinus maidis, is a major pest of agronomically-important crops. Peregrinus maidis has a large geographical distribution and transmits Maize mosaic rhabdovirus (MMV) and Maize stripe tenuivirus (MSpV). The objective of this study was to develop effective RNAi methods for P. maidis. Vacuolar-ATPase (V-ATPase) is an essential enzyme for hydrolysis of ATP and for transport of protons out of cells thereby maintaining membrane ion balance, and it has been demonstrated to be an efficacious target for RNAi in other insects. In this study, two genes encoding subunits of P. maidis V-ATPase (V-ATPase B and V-ATPase D) were chosen as RNAi target genes. The open reading frames of V-ATPase B and D were generated and used for constructing dsRNA fragments. Experiments were conducted using oral delivery and microinjection of V-ATPase B and V-ATPase D dsRNA to investigate the effectiveness of RNAi in P. maidis. Real-time quantitative reverse transcriptase-PCR (qRT-PCR) analysis indicated that microinjection of V-ATPase dsRNA led to a minimum reduction of 27-fold in the normalized abundance of V-ATPase transcripts two days post injection, while ingestion of dsRNA resulted in a two-fold reduction after six days of feeding. While both methods of dsRNA delivery resulted in knockdown of target transcripts, the injection method was more rapid and effective. The reduction in V-ATPase transcript abundance resulted in observable phenotypes. Specifically, the development of nymphs injected with 200 ng of either V-ATPase B or D dsRNA was impaired, resulting in higher mortality and lower fecundity than control insects injected with GFP dsRNA. Microscopic examination of these insects revealed that female reproductive organs did not develop normally. The successful development of RNAi in P. maidis to target specific genes will enable the development of new insect control strategies and functional analysis of vital genes and genes associated with interactions between P. maidis and MMV.
-
analysis of expressed sequence tags from maize mosaic rhabdovirus infected gut tissues of Peregrinus maidis reveals the presence of key components of insect innate immunity
Insect Molecular Biology, 2011Co-Authors: Anna E. Whitfield, Dorith Rotenberg, V Aritua, Saskia A. HogenhoutAbstract:The corn planthopper, Peregrinus maidis, causes direct feeding damage to plants and transmits Maize mosaic rhabdovirus (MMV) in a persistent-propagative manner. MMV must cross several insect tissue layers for successful transmission to occur, and the gut serves as an important barrier for rhabdovirus transmission. In order to facilitate the identification of proteins that may interact with MMV either by facilitating acquisition or responding to virus infection, we generated and analysed the gut transcriptome of P. maidis. From two normalized cDNA libraries, we generated a P. maidis gut transcriptome composed of 20 771 expressed sequence tags (ESTs). Assembly of the sequences yielded 1860 contigs and 14 032 singletons, and biological roles were assigned to 5793 (36%). Comparison of P. maidis ESTs with other insect amino acid sequences revealed that P. maidis shares greatest sequence similarity with another hemipteran, the brown planthopper Nilaparvata lugens. We identified 202 P. maidis transcripts with putative homology to proteins associated with insect innate immunity, including those implicated in the Toll, Imd, JAK/STAT, Jnk and the small-interfering RNA-mediated pathways. Sequence comparisons between our P. maidis gut EST collection and the currently available National Center for Biotechnology Information EST database collection for Ni. lugens revealed that a pathogen recognition receptor in the Imd pathway, peptidoglycan recognition protein-long class (PGRP-LC), is present in these two members of the family Delphacidae; however, these recognition receptors are lacking in the model hemipteran Acyrthosiphon pisum. In addition, we identified sequences in the P. maidis gut transcriptome that share significant amino acid sequence similarities with the rhabdovirus receptor molecule, acetylcholine receptor (AChR), found in other hosts. This EST analysis sheds new light on immune response pathways in hemipteran guts that will be useful for further dissecting innate defence response pathways to rhabdovirus infection.