The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform

Michel Peterschmitt - 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, 2009
    Co-Authors: Bernard Reynaud, Michel Peterschmitt, H. Delatte, D. Fargette
    Abstract:

    The epidemiologies of Maize streak virus (MSV), Maize stripe virus (MSpV), and Maize mosaic virus (MMV) were compared in La Réunion 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.

  • Large accumulations of maize streak virus in the filter chamber and midgut cells of the leafhopper vector Cicadulina mbila
    Archives of Virology, 2009
    Co-Authors: El-desouky Ammar, Jean-michel Lett, Daniel Gargani, Michel Peterschmitt
    Abstract:

    Maize streak virus (MSV, Mastrevirus, Geminiviridae ) is persistently transmitted by Cicadulina mbila , apparently without propagation in its leafhopper vector. MSV was shown earlier by quantitative PCR to accumulate in the alimentary canal of C. mbila . We examined the alimentary canals of C. mbila leafhoppers that acquired MSV from diseased plants for various acquisition access periods (AAP) by immunofluorescence confocal laser scanning microscopy (iCLSM) and by immunogold labelling transmission electron microscopy (iTEM). Following a 7-day AAP and a 7-day inoculation period (IP) on healthy seedlings, MSV was detected by iCLSM mainly in the filter chamber and anterior midgut. Using iTEM, large accumulations of MSV particles, usually enclosed in membranous vesicles, were detected only in cells of the midgut, inside and outside the filter chamber, following 14- or 30-day AAPs, and also following 7-day AAP and 7-day IP on healthy plants. No virus was detected in the control non-vector species C. chinaï . Coated pits or vesicles, typical of clathrin-mediated endocytosis, were not observed. We discuss an alternative endocytosis pathway and suggest that the MSV accumulations are stored in endosomes in the midgut epithelial cells.

  • Effects of temperature increase on the epidemiology of three major vector-borne viruses
    European Journal of Plant Pathology, 2008
    Co-Authors: Bernard Reynaud, Michel Peterschmitt, H. Delatte, D. Fargette
    Abstract:

    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.

  • large accumulations of maize streak virus in epithelial cells of the filter chamber of the leafhopper vector Cicadulina mbila
    Advances in plant virology : A three day International conference at CIRAD Montpellier France on 29 September - 1 October 2003, 2003
    Co-Authors: El-desouky Ammar, Jean-michel Lett, Daniel Gargani, Michel Peterschmitt
    Abstract:

    Maize streak virus (MSV), family Geminiviridae, genus Mastrevirus, is transmitted in a persistent, circulative manner by several leafhoppers, mainly Cicadulina mbila. Although no evidence is available to support MSV multiplication in its vector, MSV is usually retained through the life of the leafhopper vector. Furthermore, MSV concentration usually increases during sustained feeding of leafhoppers on MSV infected maize, unlike Tomato yellow leaf curl virus for which the accumulation was shown to be limited in its whitefly vector. These observations suggest that MSV is efficiently accumulated in the insect body for an extended period during the vector's lifespan. Spatial distribution of MSV within C. mbila monitored with quantitative polymerase chain reaction (Lett et al., 2002, Phytopathology 92:65-74), showed that MSV is mainly stored in the intestinal tract. Using thin-sectioning electron microscopy (TEM) of leafhoppers that acquired MSV for 14 or 30 days from diseased maize plants, crystalline arrays of MSV-like particles were found in the cytoplasm of epithelial cells of the filter chamber in its vector C. mbila. These viruslike arrays were identified as MSV particles since they reacted with MSV antibodies by immunogold labeling of thin sections. These cytoplasmic MSV accumulations in the leafhopper were somewhat similar to those detected in the nuclei of infected plants also by gold-labeling TEM. In osmium-fixed samples, some MSV accumulations in the midgut epithelium seemed to be bound by membranes. These crystalline arrays were not detected in control leafhoppers that were not exposed to infected plants. The significance of these observations in understanding the mode of MSV transmission by leafhoppers will be discussed. (Texte integral)

  • Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for the transmission efficiency of geminiviruses
    2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Patrick Turpin, Frédéric Chiroleu, Michel Peterschmitt, Bernard Reynaud
    Abstract:

    The efficiency with which a plant virus is transmitted by its vector(s) depends from its feeding behavior on plants. Using a DC based system, an electrical penetration graph analysis was carried out on maize with die leafhopper Cicadulina mbila Naude (Homaptera: Cicadellidae), vector of Maize streak virus (Mastrevirus, Geminiviridae). Five distinct electrical penetration graph waveforms were distinguished by temporal and spectral features as well as by statistical analysis of their median voltage and duration. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by electromotive forces (emf). Based on the correlation between waveforms and the fine structure of the stylet pathways using transmission electron microscopy, the insect's activities have been associated with five waveforms: stylet pathway (waveform 1), active ingestion (waveform 2), stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform El and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in these cells, of which their cell content is partially ingested and their organelles integrity severely affected. These observations suggest that this specific feeding feature, typical of leafhoppers, determines their ability to acquire geminivirus virions located in the plant cell nucleus. This specific feeding behavior was compared to that of whiteflies of the genus Bemisia, vector of the geminiviruses of the genus Begomovirus, for which such a vigorous probing was not described. (Texte integral)

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, 2009
    Co-Authors: Bernard Reynaud, Michel Peterschmitt, H. Delatte, D. Fargette
    Abstract:

    The epidemiologies of Maize streak virus (MSV), Maize stripe virus (MSpV), and Maize mosaic virus (MMV) were compared in La Réunion 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.

  • Effects of temperature increase on the epidemiology of three major vector-borne viruses
    European Journal of Plant Pathology, 2008
    Co-Authors: Bernard Reynaud, Michel Peterschmitt, H. Delatte, D. Fargette
    Abstract:

    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.

  • Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for the transmission efficiency of geminiviruses
    2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Patrick Turpin, Frédéric Chiroleu, Michel Peterschmitt, Bernard Reynaud
    Abstract:

    The efficiency with which a plant virus is transmitted by its vector(s) depends from its feeding behavior on plants. Using a DC based system, an electrical penetration graph analysis was carried out on maize with die leafhopper Cicadulina mbila Naude (Homaptera: Cicadellidae), vector of Maize streak virus (Mastrevirus, Geminiviridae). Five distinct electrical penetration graph waveforms were distinguished by temporal and spectral features as well as by statistical analysis of their median voltage and duration. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by electromotive forces (emf). Based on the correlation between waveforms and the fine structure of the stylet pathways using transmission electron microscopy, the insect's activities have been associated with five waveforms: stylet pathway (waveform 1), active ingestion (waveform 2), stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform El and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in these cells, of which their cell content is partially ingested and their organelles integrity severely affected. These observations suggest that this specific feeding feature, typical of leafhoppers, determines their ability to acquire geminivirus virions located in the plant cell nucleus. This specific feeding behavior was compared to that of whiteflies of the genus Bemisia, vector of the geminiviruses of the genus Begomovirus, for which such a vigorous probing was not described. (Texte integral)

  • Spatial and Temporal Distribution of Geminiviruses in Leafhoppers of the Genus Cicadulina Monitored by Conventional and Quantitative Polymerase Chain Reaction
    Phytopathology, 2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Bernard Reynaud, Isabelle Hippolyte, Monique Royer, Stéphane Blanc, Michel Peterschmitt
    Abstract:

    ABSTRACT Spatial and temporal distribution of Maize streak virus (MSV, family Geminiviridae, genus Mastrevirus) was monitored in the vector species Cicadulina mbila and the nonvector species C. chinai using conventional and real-time quantitative polymerase chain reaction. Sustained feeding on MSV-infected plants showed that virus accumulation reaches a maximum in C. chinai, but not in C. mbila. After a 3-day acquisition access feeding period (AAP), MSV was detected in the gut, the hemolymph, and the head of C. mbila, but only in the gut of C. chinai. Similarly, Digitaria streak virus (genus Mastrevirus), which is not transmitted by either of the two species, was only detected in the gut. MSV was detected in the hemolymph of C. mbila 3 h after the beginning of the AAP. Although viral DNA progressively decreases in the vector and nonvector species after a 3-day AAP, MSV DNA remained stable in the salivary glands of C. mbila.

  • Spatial and temporal distribution of geminiviruses in leafhoppers of the genus Cicadylina monitored by conventional and quantitative PCR
    2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Bernard Reynaud, Isabelle Hippolyte, Monique Royer, Stéphane Blanc, Michel Peterschmitt
    Abstract:

    Viruses of the family Geminiviridae and Luteoviridae are categorized as plant viruses transmitted by piercing-sucking insects in a circulative nonpropagative manner. However, although the mechanisms of this transmission have been well reported for several viruses of the family Luteoviridae, there are only fragmentary results for geminiviruses. Due to the numerous differences between viruses belonging to these two families, the results obtained for one cannot easily be extrapolated to the other. The aim of this work was to further study the geminivirus circulation in its vectors in the case of mastreviruses transmitted by leafhoppers. Spatial and temporal distribution of Maize streak virus (MSV, Mastrevirus, Geminiviridae) was monitored in the vector species Cicadulina mbila and a non vector species C. chinai, using conventional and/or real-time quantitative PCR. Sustained feeding on MSV infected plants, showed that virus accumulation reaches a maximum in C. chinai, but not in C. mbila. After a 3-day acquisition access feeding period (AAP), MSV is detected in the gut, the hemolymph, and the salivary glands of C. mbila, but only in the gut of C. chinai. Similarly, Digitaria streak virus (Mastrevirus, Geminiviridae) which is not transmitted by any of the two species, is only detected in the gut confirming that the gut wall is a physical barrier in the case of non transmission. MSV was detected in the hemolymph of C. mbila 3 hours after the beginning of the AAP. Although viral DNA is progressively decreasing in the vector and non vector species after a 3-day AAP, MSV DNA remained stable in the salivary glands of C. mbila. This enabled us to propose a model explaining the circulation of the geminivirus through their leafhopper vectors, consistent with the circulative nonpropagative transmission. (Texte integral)

Jean-michel Lett - One of the best experts on this subject based on the ideXlab platform.

  • Large accumulations of maize streak virus in the filter chamber and midgut cells of the leafhopper vector Cicadulina mbila
    Archives of Virology, 2009
    Co-Authors: El-desouky Ammar, Jean-michel Lett, Daniel Gargani, Michel Peterschmitt
    Abstract:

    Maize streak virus (MSV, Mastrevirus, Geminiviridae ) is persistently transmitted by Cicadulina mbila , apparently without propagation in its leafhopper vector. MSV was shown earlier by quantitative PCR to accumulate in the alimentary canal of C. mbila . We examined the alimentary canals of C. mbila leafhoppers that acquired MSV from diseased plants for various acquisition access periods (AAP) by immunofluorescence confocal laser scanning microscopy (iCLSM) and by immunogold labelling transmission electron microscopy (iTEM). Following a 7-day AAP and a 7-day inoculation period (IP) on healthy seedlings, MSV was detected by iCLSM mainly in the filter chamber and anterior midgut. Using iTEM, large accumulations of MSV particles, usually enclosed in membranous vesicles, were detected only in cells of the midgut, inside and outside the filter chamber, following 14- or 30-day AAPs, and also following 7-day AAP and 7-day IP on healthy plants. No virus was detected in the control non-vector species C. chinaï . Coated pits or vesicles, typical of clathrin-mediated endocytosis, were not observed. We discuss an alternative endocytosis pathway and suggest that the MSV accumulations are stored in endosomes in the midgut epithelial cells.

  • large accumulations of maize streak virus in epithelial cells of the filter chamber of the leafhopper vector Cicadulina mbila
    Advances in plant virology : A three day International conference at CIRAD Montpellier France on 29 September - 1 October 2003, 2003
    Co-Authors: El-desouky Ammar, Jean-michel Lett, Daniel Gargani, Michel Peterschmitt
    Abstract:

    Maize streak virus (MSV), family Geminiviridae, genus Mastrevirus, is transmitted in a persistent, circulative manner by several leafhoppers, mainly Cicadulina mbila. Although no evidence is available to support MSV multiplication in its vector, MSV is usually retained through the life of the leafhopper vector. Furthermore, MSV concentration usually increases during sustained feeding of leafhoppers on MSV infected maize, unlike Tomato yellow leaf curl virus for which the accumulation was shown to be limited in its whitefly vector. These observations suggest that MSV is efficiently accumulated in the insect body for an extended period during the vector's lifespan. Spatial distribution of MSV within C. mbila monitored with quantitative polymerase chain reaction (Lett et al., 2002, Phytopathology 92:65-74), showed that MSV is mainly stored in the intestinal tract. Using thin-sectioning electron microscopy (TEM) of leafhoppers that acquired MSV for 14 or 30 days from diseased maize plants, crystalline arrays of MSV-like particles were found in the cytoplasm of epithelial cells of the filter chamber in its vector C. mbila. These viruslike arrays were identified as MSV particles since they reacted with MSV antibodies by immunogold labeling of thin sections. These cytoplasmic MSV accumulations in the leafhopper were somewhat similar to those detected in the nuclei of infected plants also by gold-labeling TEM. In osmium-fixed samples, some MSV accumulations in the midgut epithelium seemed to be bound by membranes. These crystalline arrays were not detected in control leafhoppers that were not exposed to infected plants. The significance of these observations in understanding the mode of MSV transmission by leafhoppers will be discussed. (Texte integral)

  • Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for the transmission efficiency of geminiviruses
    2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Patrick Turpin, Frédéric Chiroleu, Michel Peterschmitt, Bernard Reynaud
    Abstract:

    The efficiency with which a plant virus is transmitted by its vector(s) depends from its feeding behavior on plants. Using a DC based system, an electrical penetration graph analysis was carried out on maize with die leafhopper Cicadulina mbila Naude (Homaptera: Cicadellidae), vector of Maize streak virus (Mastrevirus, Geminiviridae). Five distinct electrical penetration graph waveforms were distinguished by temporal and spectral features as well as by statistical analysis of their median voltage and duration. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by electromotive forces (emf). Based on the correlation between waveforms and the fine structure of the stylet pathways using transmission electron microscopy, the insect's activities have been associated with five waveforms: stylet pathway (waveform 1), active ingestion (waveform 2), stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform El and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in these cells, of which their cell content is partially ingested and their organelles integrity severely affected. These observations suggest that this specific feeding feature, typical of leafhoppers, determines their ability to acquire geminivirus virions located in the plant cell nucleus. This specific feeding behavior was compared to that of whiteflies of the genus Bemisia, vector of the geminiviruses of the genus Begomovirus, for which such a vigorous probing was not described. (Texte integral)

  • Spatial and Temporal Distribution of Geminiviruses in Leafhoppers of the Genus Cicadulina Monitored by Conventional and Quantitative Polymerase Chain Reaction
    Phytopathology, 2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Bernard Reynaud, Isabelle Hippolyte, Monique Royer, Stéphane Blanc, Michel Peterschmitt
    Abstract:

    ABSTRACT Spatial and temporal distribution of Maize streak virus (MSV, family Geminiviridae, genus Mastrevirus) was monitored in the vector species Cicadulina mbila and the nonvector species C. chinai using conventional and real-time quantitative polymerase chain reaction. Sustained feeding on MSV-infected plants showed that virus accumulation reaches a maximum in C. chinai, but not in C. mbila. After a 3-day acquisition access feeding period (AAP), MSV was detected in the gut, the hemolymph, and the head of C. mbila, but only in the gut of C. chinai. Similarly, Digitaria streak virus (genus Mastrevirus), which is not transmitted by either of the two species, was only detected in the gut. MSV was detected in the hemolymph of C. mbila 3 h after the beginning of the AAP. Although viral DNA progressively decreases in the vector and nonvector species after a 3-day AAP, MSV DNA remained stable in the salivary glands of C. mbila.

  • Spatial and temporal distribution of geminiviruses in leafhoppers of the genus Cicadylina monitored by conventional and quantitative PCR
    2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Bernard Reynaud, Isabelle Hippolyte, Monique Royer, Stéphane Blanc, Michel Peterschmitt
    Abstract:

    Viruses of the family Geminiviridae and Luteoviridae are categorized as plant viruses transmitted by piercing-sucking insects in a circulative nonpropagative manner. However, although the mechanisms of this transmission have been well reported for several viruses of the family Luteoviridae, there are only fragmentary results for geminiviruses. Due to the numerous differences between viruses belonging to these two families, the results obtained for one cannot easily be extrapolated to the other. The aim of this work was to further study the geminivirus circulation in its vectors in the case of mastreviruses transmitted by leafhoppers. Spatial and temporal distribution of Maize streak virus (MSV, Mastrevirus, Geminiviridae) was monitored in the vector species Cicadulina mbila and a non vector species C. chinai, using conventional and/or real-time quantitative PCR. Sustained feeding on MSV infected plants, showed that virus accumulation reaches a maximum in C. chinai, but not in C. mbila. After a 3-day acquisition access feeding period (AAP), MSV is detected in the gut, the hemolymph, and the salivary glands of C. mbila, but only in the gut of C. chinai. Similarly, Digitaria streak virus (Mastrevirus, Geminiviridae) which is not transmitted by any of the two species, is only detected in the gut confirming that the gut wall is a physical barrier in the case of non transmission. MSV was detected in the hemolymph of C. mbila 3 hours after the beginning of the AAP. Although viral DNA is progressively decreasing in the vector and non vector species after a 3-day AAP, MSV DNA remained stable in the salivary glands of C. mbila. This enabled us to propose a model explaining the circulation of the geminivirus through their leafhopper vectors, consistent with the circulative nonpropagative transmission. (Texte integral)

Martine Granier - One of the best experts on this subject based on the ideXlab platform.

  • Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for the transmission efficiency of geminiviruses
    2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Patrick Turpin, Frédéric Chiroleu, Michel Peterschmitt, Bernard Reynaud
    Abstract:

    The efficiency with which a plant virus is transmitted by its vector(s) depends from its feeding behavior on plants. Using a DC based system, an electrical penetration graph analysis was carried out on maize with die leafhopper Cicadulina mbila Naude (Homaptera: Cicadellidae), vector of Maize streak virus (Mastrevirus, Geminiviridae). Five distinct electrical penetration graph waveforms were distinguished by temporal and spectral features as well as by statistical analysis of their median voltage and duration. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by electromotive forces (emf). Based on the correlation between waveforms and the fine structure of the stylet pathways using transmission electron microscopy, the insect's activities have been associated with five waveforms: stylet pathway (waveform 1), active ingestion (waveform 2), stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform El and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in these cells, of which their cell content is partially ingested and their organelles integrity severely affected. These observations suggest that this specific feeding feature, typical of leafhoppers, determines their ability to acquire geminivirus virions located in the plant cell nucleus. This specific feeding behavior was compared to that of whiteflies of the genus Bemisia, vector of the geminiviruses of the genus Begomovirus, for which such a vigorous probing was not described. (Texte integral)

  • Spatial and Temporal Distribution of Geminiviruses in Leafhoppers of the Genus Cicadulina Monitored by Conventional and Quantitative Polymerase Chain Reaction
    Phytopathology, 2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Bernard Reynaud, Isabelle Hippolyte, Monique Royer, Stéphane Blanc, Michel Peterschmitt
    Abstract:

    ABSTRACT Spatial and temporal distribution of Maize streak virus (MSV, family Geminiviridae, genus Mastrevirus) was monitored in the vector species Cicadulina mbila and the nonvector species C. chinai using conventional and real-time quantitative polymerase chain reaction. Sustained feeding on MSV-infected plants showed that virus accumulation reaches a maximum in C. chinai, but not in C. mbila. After a 3-day acquisition access feeding period (AAP), MSV was detected in the gut, the hemolymph, and the head of C. mbila, but only in the gut of C. chinai. Similarly, Digitaria streak virus (genus Mastrevirus), which is not transmitted by either of the two species, was only detected in the gut. MSV was detected in the hemolymph of C. mbila 3 h after the beginning of the AAP. Although viral DNA progressively decreases in the vector and nonvector species after a 3-day AAP, MSV DNA remained stable in the salivary glands of C. mbila.

  • Spatial and temporal distribution of geminiviruses in leafhoppers of the genus Cicadylina monitored by conventional and quantitative PCR
    2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Bernard Reynaud, Isabelle Hippolyte, Monique Royer, Stéphane Blanc, Michel Peterschmitt
    Abstract:

    Viruses of the family Geminiviridae and Luteoviridae are categorized as plant viruses transmitted by piercing-sucking insects in a circulative nonpropagative manner. However, although the mechanisms of this transmission have been well reported for several viruses of the family Luteoviridae, there are only fragmentary results for geminiviruses. Due to the numerous differences between viruses belonging to these two families, the results obtained for one cannot easily be extrapolated to the other. The aim of this work was to further study the geminivirus circulation in its vectors in the case of mastreviruses transmitted by leafhoppers. Spatial and temporal distribution of Maize streak virus (MSV, Mastrevirus, Geminiviridae) was monitored in the vector species Cicadulina mbila and a non vector species C. chinai, using conventional and/or real-time quantitative PCR. Sustained feeding on MSV infected plants, showed that virus accumulation reaches a maximum in C. chinai, but not in C. mbila. After a 3-day acquisition access feeding period (AAP), MSV is detected in the gut, the hemolymph, and the salivary glands of C. mbila, but only in the gut of C. chinai. Similarly, Digitaria streak virus (Mastrevirus, Geminiviridae) which is not transmitted by any of the two species, is only detected in the gut confirming that the gut wall is a physical barrier in the case of non transmission. MSV was detected in the hemolymph of C. mbila 3 hours after the beginning of the AAP. Although viral DNA is progressively decreasing in the vector and non vector species after a 3-day AAP, MSV DNA remained stable in the salivary glands of C. mbila. This enabled us to propose a model explaining the circulation of the geminivirus through their leafhopper vectors, consistent with the circulative nonpropagative transmission. (Texte integral)

  • Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for virus transmission efficiency
    Entomologia Experimentalis et Applicata, 2001
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Patrick Turpin, Franck Molinaro, Frédéric Chiroleu, Michel Peterschmitt, Bernard Reynaud
    Abstract:

    Five distinct electrical penetration graph waveforms characterising the feeding behaviour of the leafhopper Cicadulina mbila Naudé (Homoptera: Cicadellidae) on maize ( Zea mays L.) were obtained using a DC based system. The waveforms were distinguished by spectral features and by statistical analysis of their median voltages, durations and time to first waveform recording. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by the electromotive force (emf) component. Based on the correlation between waveforms and the fine structure of the stylet pathways observed by transmission electron microscopy, insect's activities have been associated with five waveforms: stylet pathway formation (waveform 1), active ingestion (waveform 2), putative stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform E1 and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in cells, where the cell content is partially ingested and hence the organelles' integrity severely affected. These observations suggest that this specific feeding feature, typical of leafhoppers, determines their ability to acquire geminivirus virions located in the plant cell nucleus.

  • Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for virus transmission efficiency
    Entomologia Experimentalis Et Applicata, 2001
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Patrick Turpin, Franck Molinaro, Frédéric Chiroleu, Michel Peterschmitt, Bernard Reynaud
    Abstract:

    Five distinct electrical penetration graph waveforms characterising the feeding behaviour of the leafhopper Cicadulina mbila Naude (Homoptera: Cicadellidae) on maize (Zea mays L.) were obtained using a DC based system. The waveforms were distinguished by spectral features and by statistical analysis of their median voltages, durations and time to first waveform recording. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by the electromotive force (emf) component. Based on the correlation between waveforms and the fine structure of the stylet pathways observed by transmission electron rnicroscopy, insect's activities have been associated with five waveforms: stylet pathway formation (waveform 1), active ingestion (waveform 2), putative stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform E1 and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in cells, where the cell content is partially ingested and hence the organelles' integrity severely affected. These observations suggest that this specific feeding feature. typical of leafhoppers, determines their ability to acquire gerninivirus virions located in the plant cell nucleus. (Resume d'auteur)

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  • Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for the transmission efficiency of geminiviruses
    2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Patrick Turpin, Frédéric Chiroleu, Michel Peterschmitt, Bernard Reynaud
    Abstract:

    The efficiency with which a plant virus is transmitted by its vector(s) depends from its feeding behavior on plants. Using a DC based system, an electrical penetration graph analysis was carried out on maize with die leafhopper Cicadulina mbila Naude (Homaptera: Cicadellidae), vector of Maize streak virus (Mastrevirus, Geminiviridae). Five distinct electrical penetration graph waveforms were distinguished by temporal and spectral features as well as by statistical analysis of their median voltage and duration. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by electromotive forces (emf). Based on the correlation between waveforms and the fine structure of the stylet pathways using transmission electron microscopy, the insect's activities have been associated with five waveforms: stylet pathway (waveform 1), active ingestion (waveform 2), stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform El and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in these cells, of which their cell content is partially ingested and their organelles integrity severely affected. These observations suggest that this specific feeding feature, typical of leafhoppers, determines their ability to acquire geminivirus virions located in the plant cell nucleus. This specific feeding behavior was compared to that of whiteflies of the genus Bemisia, vector of the geminiviruses of the genus Begomovirus, for which such a vigorous probing was not described. (Texte integral)

  • Spatial and Temporal Distribution of Geminiviruses in Leafhoppers of the Genus Cicadulina Monitored by Conventional and Quantitative Polymerase Chain Reaction
    Phytopathology, 2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Bernard Reynaud, Isabelle Hippolyte, Monique Royer, Stéphane Blanc, Michel Peterschmitt
    Abstract:

    ABSTRACT Spatial and temporal distribution of Maize streak virus (MSV, family Geminiviridae, genus Mastrevirus) was monitored in the vector species Cicadulina mbila and the nonvector species C. chinai using conventional and real-time quantitative polymerase chain reaction. Sustained feeding on MSV-infected plants showed that virus accumulation reaches a maximum in C. chinai, but not in C. mbila. After a 3-day acquisition access feeding period (AAP), MSV was detected in the gut, the hemolymph, and the head of C. mbila, but only in the gut of C. chinai. Similarly, Digitaria streak virus (genus Mastrevirus), which is not transmitted by either of the two species, was only detected in the gut. MSV was detected in the hemolymph of C. mbila 3 h after the beginning of the AAP. Although viral DNA progressively decreases in the vector and nonvector species after a 3-day AAP, MSV DNA remained stable in the salivary glands of C. mbila.

  • Spatial and temporal distribution of geminiviruses in leafhoppers of the genus Cicadylina monitored by conventional and quantitative PCR
    2002
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Bernard Reynaud, Isabelle Hippolyte, Monique Royer, Stéphane Blanc, Michel Peterschmitt
    Abstract:

    Viruses of the family Geminiviridae and Luteoviridae are categorized as plant viruses transmitted by piercing-sucking insects in a circulative nonpropagative manner. However, although the mechanisms of this transmission have been well reported for several viruses of the family Luteoviridae, there are only fragmentary results for geminiviruses. Due to the numerous differences between viruses belonging to these two families, the results obtained for one cannot easily be extrapolated to the other. The aim of this work was to further study the geminivirus circulation in its vectors in the case of mastreviruses transmitted by leafhoppers. Spatial and temporal distribution of Maize streak virus (MSV, Mastrevirus, Geminiviridae) was monitored in the vector species Cicadulina mbila and a non vector species C. chinai, using conventional and/or real-time quantitative PCR. Sustained feeding on MSV infected plants, showed that virus accumulation reaches a maximum in C. chinai, but not in C. mbila. After a 3-day acquisition access feeding period (AAP), MSV is detected in the gut, the hemolymph, and the salivary glands of C. mbila, but only in the gut of C. chinai. Similarly, Digitaria streak virus (Mastrevirus, Geminiviridae) which is not transmitted by any of the two species, is only detected in the gut confirming that the gut wall is a physical barrier in the case of non transmission. MSV was detected in the hemolymph of C. mbila 3 hours after the beginning of the AAP. Although viral DNA is progressively decreasing in the vector and non vector species after a 3-day AAP, MSV DNA remained stable in the salivary glands of C. mbila. This enabled us to propose a model explaining the circulation of the geminivirus through their leafhopper vectors, consistent with the circulative nonpropagative transmission. (Texte integral)

  • Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for virus transmission efficiency
    Entomologia Experimentalis et Applicata, 2001
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Patrick Turpin, Franck Molinaro, Frédéric Chiroleu, Michel Peterschmitt, Bernard Reynaud
    Abstract:

    Five distinct electrical penetration graph waveforms characterising the feeding behaviour of the leafhopper Cicadulina mbila Naudé (Homoptera: Cicadellidae) on maize ( Zea mays L.) were obtained using a DC based system. The waveforms were distinguished by spectral features and by statistical analysis of their median voltages, durations and time to first waveform recording. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by the electromotive force (emf) component. Based on the correlation between waveforms and the fine structure of the stylet pathways observed by transmission electron microscopy, insect's activities have been associated with five waveforms: stylet pathway formation (waveform 1), active ingestion (waveform 2), putative stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform E1 and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in cells, where the cell content is partially ingested and hence the organelles' integrity severely affected. These observations suggest that this specific feeding feature, typical of leafhoppers, determines their ability to acquire geminivirus virions located in the plant cell nucleus.

  • Electrical penetration graphs from Cicadulina mbila on maize, the fine structure of its stylet pathways and consequences for virus transmission efficiency
    Entomologia Experimentalis Et Applicata, 2001
    Co-Authors: Jean-michel Lett, Martine Granier, Martial Grondin, Patrick Turpin, Franck Molinaro, Frédéric Chiroleu, Michel Peterschmitt, Bernard Reynaud
    Abstract:

    Five distinct electrical penetration graph waveforms characterising the feeding behaviour of the leafhopper Cicadulina mbila Naude (Homoptera: Cicadellidae) on maize (Zea mays L.) were obtained using a DC based system. The waveforms were distinguished by spectral features and by statistical analysis of their median voltages, durations and time to first waveform recording. By changing the polarity of the system voltage and the level of the input resistor it was shown that the waveforms are mainly determined by the electromotive force (emf) component. Based on the correlation between waveforms and the fine structure of the stylet pathways observed by transmission electron rnicroscopy, insect's activities have been associated with five waveforms: stylet pathway formation (waveform 1), active ingestion (waveform 2), putative stylet work (waveform 3), salivation (waveform 4) and passive ingestion (waveform 5). Like waveform E1 and E2 of aphids, waveforms 4 and 5 of C. mbila correspond to feeding activities in sieve tubes. However, unlike aphids which probe briefly in non-vascular cells, waveform 2 corresponds to active ingestion in cells, where the cell content is partially ingested and hence the organelles' integrity severely affected. These observations suggest that this specific feeding feature. typical of leafhoppers, determines their ability to acquire gerninivirus virions located in the plant cell nucleus. (Resume d'auteur)