Molecular characterization of genomic components of Potato mop-top virus from Washington State

Abstract

Potato mop-top virus (PMTV) is the type species of genus Pomovirus, family Virgaviridae. The occurrence of PMTV was reported recently in the Pacific Northwestern USA. PMTV genome is characterized by three linear positive sense ssRNA molecules. As part of a study to better understand the virus biology and molecular biology, the genome of a WA isolate was characterized and we report the complete nucleotide (nt) sequence of the genomic components RNA-2, and RNA-3. RNA2 was 3134nt in length with an ORF between nt positions 314-844 that codes for the coat protein and the same ORF as a read-through extends further to nt position 2791 coding for the CPread through protein. RNA 3 was 2964nt in length and potentially encodes four ORFs – three of them forming the triple gene bock (TGB) that was shown to be involved in cell to cell movement. RNA2 also contains a 206 nt ORF present toward the 3’ end that encodes a cysteine-rich 8K protein. RFLP analysis of RNA2 and RNA 3 of the WA isolate revealed the combination of RNA2-II and RNA3-B types, the combination that is prevalent in Europe and elsewhere. The sequenced regions had 99% sequence identity with the corresponding RNA components reported from Europe. The high degree of sequence identity could be useful in developing virus detection tools and for designing RNAi-based virus management strategies.