Abstract: A Turnip mosaic virus (TuMV) isolate (TuMV-Ra) was obtained from the radish root with symptom of red flesh in Weifang. The coat protein (CP) gene of TuMV-Ra was amplified by RT-PCR and its complete nucleotide sequence was determined. Homologies of the nucleotide and deduced amino acid sequences were compared between the CP region of TuMV-Ra and those of 20 TuMV radish isolates in GenBank. TuMV-Ra shared identities of 89.9% - 99.0% and 94.8% - 99.7% with these 20 radish isolates in nucleotide and corresponding amino acid sequences. It had highest homologies with two isolates from Hangzhou, HZLB1 and HZLB2, which amounted to 98.7% and 99.0% at nucleotide level and 99.0% and 99.7% at amino acid level. The nucleotide and amino acid sequences similarities between TuMV-Ra and CHINA-WF (obtained from the red flesh radish of Weifang in 1999) were 93.66% and 96.53% respectively. Most of the mutations occurred at the N terminus of CP. The CP gene of TuMV-Ra was cloned into expression vector pET22b ( + ) , transferred into E. coli BL21 (DE3) and exp ressed as a 38 kD fusion protein when induced with IPTG. The result ofwestern blotting assay showed that TuMV-Ra CP gene had been correctly expressed.

Key words: Turnip m osa ic virus, Radish, CP gene, Molecular characterization, Gene exp ression