关键词: 菊花, 菊花矮化类病毒, 斑点杂交, RT-PCR, 序列分析

Abstract: The chrysanthemum stunt disease，caused by Chrysanthemum stunt viroid（CSVd），is a serious threat to chrysanthemum production. To survey the occurrence and epidemic of CSVd and analyze the molecular characterization of CSVd isolates of China. In total of 122 samples，including both wild and commercial cultivars，were collected from Beijing，Wanning in Hainan，Harbin and Hefei in China. The total RNA of chrysanthemum samples were extracted by modified CTAB method and then detected by dot-blot hybridization using cRNA probe of CSVd. The positive samples tested by dot-blot hybridization were further detected by RT-PCR. cDNA of CSVd was cloned and sequenced. The results of dot-blot hybridization showed that 14 samples were positive for CSVd，which occurred in all the regions except for Harbin at infection ratio of 11.5%. Sequences analysis indicated that CSVd isolates of China shared the most close relationship with CSVd isolates of Korea and Japan. Compared with reference sequence of CSVd（NC002015），there were 21 mutations for CSVd isolates of China. The prediction of secondary structure showed the mutations，most of which happened in pathogenicity region，have no impact on folding into stable rod-like structure.

Key words: chrysanthemum, Chrysanthemum stunt viroid, dot-blot hybridization, RT-PCR, sequence analysis