Characterisation and partial sequence of a new furovirus of wheat in China

A soil‐borne wheat virus causing severe mosaic and stunting symptoms on wheat in China has been characterized. It had been considered to be soil‐borne wheat mosaic virus (SBWMV) because of its rod‐shaped virions and similarities to epidemiology and host range. In this study, the virions purified from infected wheat tissue were approximately 20 nm in diameter and of two lengths (140–160 nm and 280–300 nm), with a coat protein of 19 kDa and two RNA components of approximately 7 and 3.5 kb. A rabbit antiserum was produced against the virus and a serological relationship to SBWMV from the USA (Oklahoma) was demonstrated. However, the coat protein was not recognized by most monoclonal antibodies against Oklahoma SBWMV in either ELISA, ISEM or Western blot analysis, indicating epitope differences. In RT‐PCR experiments the viral nucleotide sequences were significantly different from those of SBWMV, and this was confirmed by partial sequencing of the cloned PCR fragments generated from RNA1 (c. 1100 nt) and RNA2 (c. 1400 nt), which showed homologies of about 79 and 63%, respectively, to corresponding regions of SBWMV. Because of these significant differences in serology and nucleotide sequence it is suggested that it is a new furovirus for which the name Chinese wheat mosaic virus (CWMV) is proposed.