国家自然科学基金 (39870 434 )，广东省自然科学基金 (980 12 6)，高等学校博士点基金 (95 0 5 0 3)
By regular gene cloning techniques, DNA component 6 of the representative isolate of BBTV (banan bunchy top virus) NS strain was cloned and sequenced. The sequence was compared with the sequence of DNA component 6 of Guangzhou Tianhe isolate (belong to NSP strain) reported. The results showed that the variance ratios of full sequence of the component 6,the ORF nucleotide sequence and its encoding amino acid sequence between the two isolates were 3 4%, 1.7% and 2.6% respectively.Results in the experiment showed that the differences of the component between the two representative isolates of the NSP and NS strains respectively were significant, and that further supported that there were NSP and NS strains of Guangdong BBTV. In addition, the variance ratios of the full sequences of the component, the ORF nucleotide sequences and its encoding CP amino acid sequences were 14.4%, 7 5% and 7 1% respectively between the Gaozhou isolate and the Australia isolate.