Infectivity, effects on helper viruses and whitefly transmission of the deltasatellites associated with sweepoviruses (genus Begomovirus, family Geminiviridae)

Abstract

Begomoviruses (family Geminiviridae) are whitefly-transmitted viruses with single-stranded DNA genomes that are frequently associated with DNA satellites. These satellites include non-coding satellites, for which the name deltasatellites has been proposed. Although the first deltasatellite was identified in the late 1990s, little is known about the effects they have on infections of their helper begomoviruses. Recently a group of deltasatellites were identified associated with sweepoviruses, a group of phylogenetically distinct begomoviruses that infect plants of the family Convolvulaceae including sweet potato. In this work, the deltasatellites associated with sweepoviruses are shown to be transreplicated and maintained in plants by the virus with which they were identified, sweet potato leaf curl virus (SPLCV). These deltasatellites were shown generally to reduce symptom severity of the virus infection by reducing virus DNA levels. Additionally they were shown to be maintained in plants, and reduce the symptoms induced by two Old World monopartite begomoviruses, tomato yellow leaf curl virus and tomato yellow leaf curl Sardinia virus. Finally one of the satellites was shown to be transmitted plant-to-plant in the presence of SPLCV by the whitefly vector of the virus, Bemisia tabaci, being the first time a deltasatellite has been shown to be insect transmitted.

Molecular and Biological Characterization of a New World Mono-/Bipartite Begomovirus/Deltasatellite Complex Infecting Corchorus siliquosus

“…Neither of the deltasatellites influenced the symptoms caused by their natural helper begomoviruses in N. benthamiana or in their natural hosts (Fiallo-Olivé et al, 2016). In contrast, deltasatellites associated with sweet potato leaf curl virus, a sweepovirus, usually reduced symptom severity caused by its natural helper virus and by tomato leaf curl virus, a monopartite Old World begomovirus (Hassan et al, 2016).…”

Maintenance of Cotton Leaf Curl Multan Betasatellite by Tomato Leaf Curl New Delhi Virus—Analysis by Mutation

“…Having investigated the interactions between a betasatellite and both monopartite and bipartite helper begomoviruses, it will be interesting to investigate the effects of mutations of virus-encoded genes on the other geminivirus-associated satellites, the alphasatellites and the betasatellite-derived deltasatellites (Dry et al, 1997 ; Nawaz-ul-Rehman et al, 2010 ; Idris et al, 2011 ; Fiallo-Olivé et al, 2012 , 2016 ; Hassan et al, 2016 ; Lozano et al, 2016 ). Both types of molecules appear to lack a strong selection mechanism for their maintenance by begomoviruses (such as that provided, in some hosts, by βC1 for betasatellites) and alphasatellites differ from betasatellites in being capable of autonomous replication (Mansoor et al, 1999 ).…”

Multifaceted role of geminivirus associated betasatellite in pathogenesis

“…Interestingly, the interaction between alpha‐Rep and helper virus Rep leads to inhibition of accumulation of betasatellites, which too, rely on helper virus Rep for their replication (Nawaz‐Ul‐Rehman et al ., ; Vinoth Kumar et al ., ). Deltasatellites are non‐coding, circular single‐stranded satellite DNA molecules associated with begomoviruses (Lozano et al ., ) and are reported to reduce both the accumulation of viral DNA and helper virus‐mediated symptom development in the infected plants (Ceniceros‐Ojeda et al ., ; Hassan et al ., ).…”