Molecular Characterization and Detection of a Genetically Distinct Tomato Chlorosis Virus Strain in Taiwan

Abstract

The whitefly-transmitted tomato chlorosis virus (ToCV) belonging to the genus Crinivirus (family Closteroviridae) affects tomato production worldwide. ToCV was first recorded in Taiwan in 1998 affecting tomato production. In this study, a local virus isolate XS was obtained, after serial whitefly transmissions from a diseased tomato plant displaying general chlorosis were collected in central Taiwan. The whole genome sequence of XS was determined from cDNA fragments amplified by reverse transcription (RT)-PCR, first using the degenerate primers for viruses of Closteroviridae and followed by degenerate and specific primers designed on available sequences of the ToCV isolates. The nucleotide (nt) sequences of RNA-1 and RNA-2 of the XS shared low identities of 77.8 to 78% and 78 to 78.1%, respectively, with genome segments of other ToCV isolates. Nevertheless, the viral RNA-dependent RNA polymerase (RdRp), heat shock protein 70 homolog (Hsp70h), and major capsid protein (CP) shared 88.3 to 96.2% amino acid (aa) identities with other ToCV isolates, indicating that XS is a new strain of this virus. Phylogenetic analyses of these three proteins indicated that all ToCV isolates from different counties outside Taiwan are closely related and clustered in the same clade, whereas the XS isolate is distinct and forms a unique branch. A one tube RT-PCR assay using primers designed from the genomic sequence of the XS was able to detect the ToCV-XS in infected tomato plants and in individual whiteflies. A field survey during 2013 to 2016 revealed a high ToCV-XS prevalence of 60.5% in 172 tested tomato samples, demonstrating that ToCV-XS is becoming an emerging threat for tomato production in Taiwan.

Tomato chlorosis virus, an emergent plant virus still expanding its geographical and host ranges

“…To date, 17 complete ToCV genome sequences have been published, one each from the USA (Wintermantel et al , ), Spain (Lozano et al , , ), Greece (Kataya et al , ), Brazil (Albuquerque et al , ) and Taiwan (Kang et al , ), two from China (Zhao et al , , 2014b) and ten from Korea (Lee et al , ).…”

Suppression of Bta11975, an α‐glucosidase, by RNA interference reduces transmission of tomato chlorosis virus by Bemisia tabaci

“…Tomato chlorosis virus (ToCV), which belongs to the family Closteroviridae and the genus Crinivirus, 1 was first discovered in Florida, USA, causing a ‘yellow leaf disorder’ syndrome in tomato plants and since then, has spread widely around the world 2–6 . In China, ToCV was first reported in Taiwan 7 and was subsequently found in most other locations in the country. ToCV causes an important disease that affects tomato production by up to 76.6% or higher 8 …”

Design, Synthesis, and Anti-ToCV Activity of Novel Pyrimidine Derivatives Bearing a Dithioacetal Moiety that Targets ToCV Coat Protein

“…Various pyrimidine sulfide derivatives that bear a dithioacetal were designed (Figure ) and synthesized. Besides, their anti-ToCV activities were evaluated according to the reported method. ,− …”