[Molecular identification of cucumber mosaic virus in woad (Isatis tinctoria) with mosaic disease in Beijing]

To detect possible pathogenic virus(es) in woad (Isatis tinctoria) cultivated at Institute of Medicinal Plant Development in Beijing, reverse transcription(RT)-PCR was performed using total RNA of symptomatic woad leaves with primers for poty-, polero-, tobamovirus, broad bean wilt virus 2(BBWV2) and cucumber mosaic virus (CMV). A 657 bp fragment was amplified from symptomatic woad using CMV primers. Sequencing and BLAST analysis indicated that this fragment shared 99% nucleotide identity and 100% amino acid identity with CMV-Vi isolate. The isolate was named CMV-Isatis tinctorial (CMV-It). Phylogenetic analysis based on nucleotide sequences of CP genes showed that CMV-It clustered with CMV-K and belonged to subgroup I. To our knowledge, this is first identification of CMV in woad by RT-PCR and the CP gene was analyzed. This work provided data for research and control of woad mosaic disease.