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Spatial and temporal distribution of geminiviruses in leafhoppers of the genus Cicadylina monitored by conventional and quantitative PCR

Lett J.M., Granier M., Hippolyte I., Grondin M., Royer M., Blanc S., Reynaud B., Peterschmitt M.. 2002. In : SFM, IUMS. The world of microbes : XIIth International Congress of Virology, Paris, 27th July to 1st August 2002. Paris : EDK, p. 413-413. International Congress of Virology. 11, 2002-07-27/2002-08-01, Paris (France).

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. chinaï, using conventional and/or real-time quantitative PCR. Sustained feeding on MSV infected plants, showed that virus accumulation reaches a maximum in C. chinaï, 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. chinaï. 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 intégral)

Mots-clés : géminivirus striure du maïs; virus des végétaux; cicadulina; distribution tissulaire; pcr; cicadulina mbila; cicadulina chinai

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