Revealing the Complexity of Sweepovirus-Deltasatellite-Plant Host Interactions: Expanded Natural and Experimental Helper Virus Range and Effect Dependence on Virus-Host Combination.

Camila G Ferro,Elvira Fiallo-Olivé,F Murilo Zerbini,Jesús Navas-Castillo

doi:10.3390/microorganisms9051018

Abstract

Sweepoviruses are begomoviruses (genus Begomovirus, family Geminiviridae) with ssDNA genomes infecting sweet potato and other species of the family Convolvulaceae. Deltasatellites (genus Deltasatellite, family Tolecusatellitidae) are small-size non-coding DNA satellites associated with begomoviruses. In this study, the genetic diversity of deltasatellites associated with sweepoviruses infecting Ipomoea indica plants was analyzed by further sampling the populations where the deltasatellite sweet potato leaf curl deltasatellite 1 (SPLCD1) was initially found, expanding the search to other geographical areas in southern continental Spain and the Canary Islands. The sweepoviruses present in the samples coinfected with deltasatellites were also fully characterized by sequencing in order to define the range of viruses that could act as helper viruses in nature. Additionally, experiments were performed to assess the ability of a number of geminivirids (the monopartite tomato leaf deformation virus and the bipartite NW begomovirus Sida golden yellow vein virus, the bipartite OW begomovirus tomato leaf curl New Delhi virus, and the curtovirus beet curly top virus) to transreplicate SPLCD1 in their natural plant hosts or the experimental host Nicotiana benthamiana. The results show that SPLCD1 can be transreplicated by all the geminivirids assayed in N. benthamiana and by tomato leaf curl New Delhi virus in zucchini. The presence of SPLCD1 did not affect the symptomatology caused by the helper viruses, and its effect on viral DNA accumulation depended on the helper virus–host plant combination.

Highlights

IntroductionBegomoviruses (genus Begomovirus, family Geminiviridae) have circular, single-stranded
Begomoviruses have circular, single-strandedDNA genomes composed of one or two genomic components
The results show that sweet potato leaf curl deltasatellite 1 (SPLCD1) was transreplicated by all the geminivirids assayed at least in N. benthamiana, that SPLCD1did not affect the symptomatology caused by the helper viruses, and that their effect on viral DNA accumulation depended on the helper virus–host plant combination

Summary

Introduction

Begomoviruses (genus Begomovirus, family Geminiviridae) have circular, single-stranded. DNA (ssDNA) genomes composed of one or two genomic components. They are encapsidated in twinned quasi-icosahedral (geminate) particles [1]. The sweepoviruses are begomoviruses infecting sweet potato (Ipomoea batatas) and other species of the family Convolvulaceae that group in a cluster basal to the main phylogenetic groups in the genus, the Old World (OW) and the New World (NW) begomoviruses [4,5]. The sweepoviruses have the typical genomic organization of the monopartite begomoviruses originating from the OW [1,16]. The virion-sense strand encodes the coat protein (CP) with function in particle formation and is essential for viral

Methods

Results

Conclusion