Complete genome sequence of vallota mosaic virus detected in a narcissus bulb imported from the United States to Japan.

Narcissus (Narcissus albidus) imported from the United States exhibited leaf chlorosis during post-entry quarantine. We employed next-generation sequencing (NGS) on symptomatic leaf samples and detected vallota mosaic virus (ValMV), belonging to the genus Potyvirus, family Potyviridae, as the viral agent. Sanger sequencing of PCR products and rapid amplification of cDNA ends based on NGS contigs revealed that ValMV is 9,451 nucleotides (nt) in length, excluding the poly(A) tail. Nucleotide and amino acid (aa) sequences of the coat protein region had over 98% identity to previously reported ValMV isolates. In each of the 10 regions encoding mature proteins, however, the sequence identity to other potyviruses was 49.5-71.9% nt and 18.3-78.9% aa, values that are below the species demarcation thresholds for the family Potyviridae. Phylogenetic analysis revealed that our ValMV isolate is most closely related to known ValMV isolates and is grouped with other potyviruses. Taken together, our results indicate that the newly isolated ValMV belongs to a distinct species in the genus Potyvirus. This study provides the first report of the complete ValMV genome sequence and the first record of this virus in narcissus.

Complete genome sequences of anemone mosaic virus and ranunculus mild mosaic virus isolated from anemone imported from the Netherlands into Japan.

Anemone mosaic virus (AnMV) and ranunculus mild mosaic virus (RanMMV) infect anemone plants, which exhibit characteristic mosaic patterns on their leaves. Employing next-generation sequencing of plant material imported from the Netherlands, the complete genome sequences of these two viruses were determined for the first time. AnMV and RanMMV have 9698 and 9537 nucleotides (nt), respectively, excluding the poly(A) tail. They share 80.0%/82.0% and 98.0%/97.0% nt/amino acid (aa) sequence identity, which is above the species demarcation value, in the previously reported AnMV and RanMMV coat protein sequences, but they share 69.0%/70.0% nt/aa sequence identity or less with other potyviruses in all 10 mature protein coding regions of the genome. Additionally, phylogenetic analysis confirmed the relationship of the AnMV and RanMMV genome sequences to previously reported partial sequences and placed them within the genus Potyvirus. These results show that these two viruses represent separate species within the genus Potyvirus.