Detection and characterization of Tomato spotted wilt virus infecting field and greenhouse-grown crops in Zimbabwe

Charles Karavina,Augustine Gubba

doi:10.1007/s10658-017-1243-4

Abstract

Tomato spotted wilt virus (TSWV), the type species of the genus Tospovirus in the family Bunyaviridae, is one of the most economically important emerging plant viruses worldwide. It causes over US$1 billion losses annually in open field and greenhouse-grown crops. A study was carried out to determine the geographical distribution, host range and phylogeny of TSWV in Zimbabwe. Disease surveys were conducted in 18 districts over a three-year period using tospovirus immunostrips. Virus-infected leaf samples were collected on FTA cards and in RNAlater solution. TSWV was characterized by double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA) and reverse transcription polymerase chain reaction (RT-PCR) followed by sequencing and phylogenetic analysis. The virus was detected in 50% of the districts surveyed, mostly in the country’s prime agricultural region. It was confirmed to be present by DAS-ELISA and RT-PCR. In addition to some previously reported hosts, TSWV was detected for the first time in Cucurbita moschata, Cucurbita pepo, Cucumis sativus and Gyposphila elegans. Molecular analysis of the TSWV nucleocapsid gene showed that Zimbabwean TSWV isolates were highly similar (≥93.99%) and identical (99.02%) to each other at nucleotide and amino acid sequence levels. When compared to isolates from the rest of the world, Zimbabwean TSWV isolates were most closely related to isolates from Italy, Montenegro, New Zealand and Serbia. The study lays the foundation for future TSWV studies by providing protocols and procedures that could be used. Information generated in this study will be useful in formulating effective TSWV control measures.

Highlights

Tomato spotted wilt virus (TSWV), the type species of the genus Tospovirus in the family Bunyaviridae, is one of the most economically important emerging plantinfecting viruses worldwide (Tsompana et al 2005; Pappu et al 2009; Scholthof et al 2011)
We investigated the occurrence of TSWV in Zimbabwe
Tospoviruses were successfully detected from plants displaying leaf chlorosis, necrosis, crinkling and reduced size using immunostrips

Summary

Introduction

Tomato spotted wilt virus (TSWV), the type species of the genus Tospovirus in the family Bunyaviridae, is one of the most economically important emerging plantinfecting viruses worldwide (Tsompana et al 2005; Pappu et al 2009; Scholthof et al 2011). It causes losses estimated at US$1 billion annually for several important ornamental, food and cash crops worldwide (Goldbach and Peters 1994; Parrella et al 2003). At least nine thrips (Thysanoptera: Thripidae) species are known to transmit TSWV in a persistent-propagative manner, with Frankliniella occidentalis Pergande being the primary vector (Riley et al 2011; Rotenberg et al 2015)

Methods

Results

Conclusion