Co-Acquired Nanovirus and Geminivirus Exhibit a Contrasted Localization within Their Common Aphid Vector.

Jérémy Di Mattia,Marie-Stéphanie Vernerey,Nicolas Sauvion,Michel Peterschmitt,Stéphane Blanc,Elodie Pirolles,Jean-Louis Zeddam,Faustine Ryckebusch

doi:10.3390/v12030299

Abstract

Single-stranded DNA (ssDNA) plant viruses belong to the families Geminiviridae and Nanoviridae. They are transmitted by Hemipteran insects in a circulative, mostly non-propagative, manner. While geminiviruses are transmitted by leafhoppers, treehoppers, whiteflies and aphids, nanoviruses are transmitted exclusively by aphids. Circulative transmission involves complex virus–vector interactions in which epithelial cells have to be crossed and defense mechanisms counteracted. Vector taxa are considered a relevant taxonomic criterion for virus classification, indicating that viruses can evolve specific interactions with their vectors. Thus, we predicted that, although nanoviruses and geminiviruses represent related viral families, they have evolved distinct interactions with their vector. This prediction is also supported by the non-structural Nuclear Shuttle Protein (NSP) that is involved in vector transmission in nanoviruses but has no similar function in geminiviruses. Thanks to the recent discovery of aphid-transmitted geminiviruses, this prediction could be tested for the geminivirus alfalfa leaf curl virus (ALCV) and the nanovirus faba bean necrotic stunt virus (FBNSV) in their common vector, Aphis craccivora. Estimations of viral load in midgut and head of aphids, precise localization of viral DNA in cells of insect vectors and host plants, and virus transmission tests revealed that the pathway of the two viruses across the body of their common vector differs both quantitatively and qualitatively.

Highlights

All Single-stranded DNA (ssDNA) plant viruses belong to the families Geminiviridae and Nanoviridae and are transmitted by hemipteran vectors in a circulative, mostly non-propagative, manner [1,2], meaning that they persist and cycle within the body of their vectors without replication [3,4]
faba bean necrotic stunt virus (FBNSV) was found in 31%(+/−20%) and alfalfa leaf curl virus (ALCV) in 66%(+/−18%)
More important is the observation of identical symptoms in Overall, our results demonstrate that FBNSV and ALCV can co-exist in the same host mono- and co-infected plants (Figure 1A) and the absence of interference between the two viruses plant, where they accumulate as if infecting alone, and that these viruses can co-exist in the same for accumulation in plant tissues

Summary

Introduction

All ssDNA plant viruses belong to the families Geminiviridae and Nanoviridae and are transmitted by hemipteran vectors in a circulative, mostly non-propagative, manner [1,2], meaning that they persist and cycle within the body of their vectors without replication [3,4]. While nanoviruses are transmitted exclusively by insects of the family Aphididae (aphids) [5], geminiviruses are transmitted by three other hemipteran families: Cicadellidae (leafhoppers), Membracidae (treehoppers) and Aleyrodidae (whiteflies) [6,7,8]. The transmission rate of ALCV per individual aphid was much lower than that of whitefly- and leafhopper-transmitted geminiviruses [13]. It is tempting to speculate that nanoviruses, which are all transmitted by aphids, have evolved virus–vector interactions that differ from those evolved by capulaviruses

Methods

Results

Discussion

Conclusion