Analysis of ISEM, SDS PAGE, Western blot, Northern blot and RT PCR indicated that the soil borne mosaic disease occurred on winter wheat in Yantai district, Shandong Province, was caused by co infection of two different viruses. The filamentous virus was identified to be wheat yellow mosaic virus (WYMV) as it had a coat protein of 33kD, which was serologically related to WYMV, wheat spindle streak mosaic virus(WSSMV) and barley yellow mosaic virus (BaYMV), but not to barley mild mosaic virus(BaMMV) and soil borne wheat mosaic virus(SBWMV). In addition, DNA fragments specifically amplified from its cDNAs template with WYMV primers were identical to those amplified from the homologous template. The rod shaped virus was identified to be a SBWMV related virus as it had a coat protein of 19 kD, which was serologically related to SBWMV and TMV, but not to WYMV, WSSMV, BaYMV, BaMMV and three monoclonal antibodies to SBWMV. Its RNA1 (7.1kb) and RNA2 (3.6 kb) were respectively hybridized by cDNA probes of RNA1(p3H5) and RNA2(pJC2G6) of SBWMV, but no DNA fragments specifically amplified from cDNA template of its RNA with primers of SBWMV RNA 1 and RNA2.
