Complete genomic characterization of a potato mop-top virus isolate from the United States

Abstract

Potato mop-top virus (PMTV; family Virgaviridae) was reported recently in the Pacific Northwestern USA. To better understand the genetic diversity of this virus, the complete genome of an isolate from Washington State (WA), USA, was characterized. Sequence comparisons of the WA isolate with other known sequences revealed that the RNA-Rep-encoded RdRp protein and the RNA-CP-encoded coat protein displayed >99 % amino acid sequence identity to those of two Nordic (RdRp) and several European and North American isolates (CP), respectively. The RNA-TGB-encoded TGB 1 and TGB 3 protein sequences had >99 % amino acid sequence identity to the corresponding proteins of Czech and Danish isolates, whereas the TGB 2 protein is identical to those of Colombian isolates. Phylogenetic analysis of the viral genes of the WA isolate reflected the close relationship between WA and European isolates. RFLP analysis of corresponding DNA of RNA TGB and RNA CP revealed that the WA isolate has the RNA TGB-II and RNA CP-B types, which are prevalent in Europe and other parts of world. This is the first report of the complete genome characterization of PMTV from the Americas.

Molecular and pathobiological characterization of 61 Potato mop‐top virus full‐length cDNAs reveals great variability of the virus in the centre of potato domestication, novel genotypes and evidence for recombination

“…PMTV continues to pose a significant threat to potato production, as exemplified by the recent recognition of the presence of the virus in Canada (Hu et al ., ) and the USA (Ramesh et al ., ). Therefore, there is a growing need to understand the variability of the virus at a global scale.…”

“…Therefore, there is a growing need to understand the variability of the virus at a global scale. Previous studies examining the genetic composition of PMTV isolates in Europe, Asia and North America have reported low variability of the virus (Beuch et al ., ; Hu et al ., ; Ramesh et al ., ). However, it remains unclear whether low variability of PMTV is typical for all parts of the world.…”

“…Surprisingly, some RNA viruses with multipartite genomes, e.g. Potato mop‐top virus (PMTV), show variability as low as 0%–2% depending on the isolate (Beuch et al ., ; Hu et al ., ; Latvala‐Kilby et al ., ; Ramesh et al ., ). We speculated that the high genomic stability and low sequence variation of PMTV, to preserve genome integrity, might be a result of constraints imposed by the need to transport three RNA genomic components and the mode of PMTV movement in the plant as polar virions, which require rather intricate interactions between the minor coat protein (also known as CP‐RT), viral movement protein and, possibly, certain host factors at one extremity of the virus particles, leaving little room for variation (Torrance et al ., ).…”

“…PMTV infection is characterized by typical ‘spraing’ symptoms in the tuber, which consist of necrotic rings and flecks in the tuber flesh (Calvert and Harrison, ). The occurrence of the virus has been reported from many parts of the world, including Nordic countries, the Americas and parts of Asia (Hu et al ., ; Ramesh et al ., ; Santala et al ., ). The recent discovery of new genetic variants of the virus in USA and Colombia raises concern about the epidemiological risk this might bring to territories in which these variants are not present (Gil et al ., ; Ramesh et al ., ).…”

An on-site adaptable test for rapid and sensitive detection of Potato mop-top virus, a soil-borne virus of potato (Solanum tuberosum)

“…PMTV infection mainly manifests in tubers as internal necrosis and results in reduced yield and quality [ 3 ]. Since its first diagnosis in UK in 1966 [ 4 ], PMTV has been identified in most potato cultivation areas across Asia, Europe, North and South America [ 5 – 8 ]. Phylogenetic evidence supports the hypothesis that PMTV originated from the Andean region of South America [ 7 , 8 ].…”