Abstract:

【Objective】 This study was carried out to determine the pathogen causing the mosaic and mottle symptom on Bidens pilosa L.. 【Method】 Viral particles in the infected leaves were detected by electron microscopy. Serological relation between the pathogenic virus and genus Potyvirus was examined by indirect ELISA. Moreover, the sequence of the 3′-part genome of the virus was cloned by RT-PCR and sequenced by common molecular biological methods. For bioinformational analysis, programs of BLAST at NCBI, Clustal_X, BioEdit and MEGA 4.0 were used for alignment and phylogenetic tree construction. 【Result】 Electron microscopy of leaf dips from infected plants revealed flexuous particles 650-700 nm in length and 13 nm in width. Cytoplasmic laminar aggregates and pinwheel inclusions were observed in ultrathin sections. Serological reaction between the virus and the antibody of potyvirus was positive. A DNA fragment of 1.8 kb with high identity to the sequence of Bidens mottle virus (BiMoV) could be amplified through the universal primers of family Potyviridae virus. Analysis of the sequence revealed that the amino acid identity of CP and nucleotide identity of 3′UTR to corresponding sequences of BiMoV were both more than 96%. 【Conclusion】 The evidences suggests that the pathogen causing mosaic and mottle symptom on Bidens pilosa L. is BiMoV, which is the first report of BiMoV infecting a member of the Bidens L. in China.

Key words: Bidens pilosa L., genus Potyvirus, Bidens mottle virus