Spotlight on the recently discovered aphid-transmitted geminiviruses

Ryckebusch Faustine, Sauvion Nicolas, Granier Martine, Peterschmitt Michel. 2022. Spotlight on the recently discovered aphid-transmitted geminiviruses. In : Geminivirus: detection, diagnosis and management. Gaur R.K. (ed.), Sharma Pradeep (ed.), Czosnek Henryk (ed.). Londres : Academic Press, 95-105. ISBN 978-0-323-90587-9

Résumé : It was only with the advent of viral metagenomics in the 2010s that aphid-transmitted geminiviruses were discovered. The genus Capulavirus was established to accommodate them within the family Geminiviridae. Euphorbia caput-medusae latent virus (EcmLV) is the type member of the new genus, which includes Alfalfa leaf curl virus (ALCV), French bean severe leaf curl virus (FbSLCV), and Plantago lanceolata latent virus (PlLV). Several reasons can explain why they went unnoticed. EcmLV and PlLV are latent and were detected on noncultivated hosts. The symptoms induced by FbSLCV in French beans resemble those induced by some whitefly-transmitted geminiviruses and FbSLCV incidence is generally around 2%. The symptoms associated with ALCV were previously associated with a rhabdovirus. A detailed analysis of the transmission cycle of an agroinfectious clone of ALCV revealed that it is efficiently acquired by its aphid vector Aphis craccivora but its excretion rate is dramatically low compared to that of the nanovirus Faba bean necrotic stunt virus tested in parallel with the same aphid population. Consistent with its low excretion, the transmission rate of ALCV is much lower than that of nonaphid-transmitted geminiviruses, irrespective of the three A. craccivora populations tested. The transmission rate of a field-collected isolate of ALCV was similarly low. According to preliminary results and the literature, transmission rates of other capulaviruses seem to be low as well suggesting that low transmission rates are a typical feature of capulaviruses inherent to geminivirus–aphid combinations. Inefficient virus transmission may explain why capulaviruses were detected mostly in hardy perennial plants where high transmission rates are not critical. The exception of FbSLCV on French beans may be explained by a spillover infection from a potential perennial host where it may be maintained.

Auteurs et affiliations

• Ryckebusch Faustine, Université de Montpellier (FRA)
• Sauvion Nicolas, INRAE (FRA)
• Granier Martine, CIRAD-BIOS-UMR PHIM (FRA)
• Peterschmitt Michel, CIRAD-BIOS-UMR PHIM (FRA) ORCID: 0000-0001-8709-9418

Source : Cirad-Agritrop (https://agritrop.cirad.fr/602407/)

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