Occurrence and identification of major viruses infecting cigar tobacco (Nicotiana tabacum) in Hainan.

In order to identify the major virus species and infection types affecting cigar tobacco (Nicotiana tabacum) in Hainan Province, tobacco leaf samples suspected of being infected with viral diseases were collected from 7 cigar tobacco growing regions in Hainan. Specific primers of 6 viruses and universal primers of geminivirus were used for PCR detection, and the primers were designed according to the amplified sequences of TYLCV, SiLCV and AYVCNV to obtain their complete genome sequence. The results showed that 59 out of 64 samples were detected with 5 viruses (TMV, CMV, TYLCV, SiLCV and AYVCNV), and the detection rate was 92.19%. The detection rate of TMV was the highest (73.45%), followed by CMV (39.07%). The single infection rate was 60.94%, with TMV (45.31%), accounting for the highest proportion. The mixed infection rate was 31.25%, and the proportion of TMV+CMV was the highest (26.57%). Therefore, TMV was the dominant virus affecting cigar tobacco in Hainan, and the main type of mixed infection was TMV+CMV. In addition, the complete DNA-A sequences of TYLCV, SiLCV and AYVCNV were obtained. [ABSTRACT FROM AUTHOR]