A new potyvirus from Thunberg fritillary (Fritillaria thunbergii Miq.) in Zhejiang, China.

A potyvirus causing mosaic symptoms in Thunberg fritillary (Fritillaria thunbergii) was found at two sites in Zhejiang province, China. The virus was readily mechanically transmitted to its original host but not to any of 17 other widely used plant virus indicators. A polyclonal antiserum raised to purified virus particles reacted with its homologous virus but not with a range of other viruses (including 16 potyvirus species). In electron microscopy, virus particles and inclusion bodies typical of a potyvirus were seen. The complete nucleotide sequence of an isolate from Ningbo was determined. It was 9723 nt long and sequence analyses predicted the standard potyvirus organisation. The partial sequence (1664 nts at the 3'-terminus) of an isolate from Panan was also determined; the two sequences had 96.9% nt identity. In sequence comparisons and phylogenetic analyses with completely sequenced potyviruses, the new virus was most closely related to Lily mottle virus (53.0% aa identity) and Leek yellow stripe virus. The most closely related incomplete sequence in the international databases was for Lycoris mild mottle virus (72.8% nt identity in their coat proteins). These results suggest that the virus studied is a new species in the genus Potyvirus, which we have tentatively named Thunberg fritillary mosaic virus.