Abstract: In order to clarify the pathogen of Paris polyphylla var.yunnanensis virus disease in Yunnan Province, the leaves of Paris polyphylla var.yunnanensis with mosaic and mottle symptoms found in Kunming City were used as samples for transmission electron microscopy, high-throughput sequencing and RT-PCR detection. The results showed that the linear virus particles with a size of about （700~1 000） nm×13 nm were observed. Based on the results of high-throughput sequencing, specific primers were designed for RT-PCR amplification and cloning, and a virus sequence with a total length of 10 066 nucleotides （nt） was obtained. The virus was temporarily named Paris virus 1 （ParV1）; BLAST alignment analysis showed that ParV1 had the highest nucleotide and amino acid （aa） sequence homology of 65.1% and 68.9% with Thunberg fritillary mosaic virus （TFMV） in the genus Potyvirus. Multiple sequence alignment analysis showed that ParV1 had 49.6%~65.1% nt sequence homology and 47.1%~68.9% aa sequence homology with potyviruses. The phylogenetic tree based on the polyprotein amino acid sequence showed that the virus was closely related to TFMV and clustered into a separate branch. In summary, ParV1 is a new virus of Potyvirus. The virus juice containing ParV1 was inoculated into Nicotiana tabacum and Nicotiana benthamiana by mechanical friction to determine the pathogenicity of ParV1. The leaves of the inoculated Nicotiana glutinosa plants showed obvious symptoms of virus disease. The presence of ParV1 was detected in the inoculated Nicotiana glutinosa by RT-PCR and molecular cloning, indicating that the Nicotiana glutinosa plants were infected by ParV1, but the presence of the virus was not detected on the inoculated Nicotiana benthamiana.

Key words: Paris polyphylla var. yunnanensis, Paris virus 1, pathogenicity determination