Identification of Main Virus Species in Qingdao Tobacco

To clarify the main virus species and distribution of tobacco viral diseases in Qingdao, the disease surveys were conducted in three main tobacco-growing stations of Qingdao from 2023 to 2024. The pathogens causing tobacco virus diseases were identified using virome sequencing, metagenome sequencing and PCR detection. The results showed that, a total of 9 plant viruses from 6 families and 6 genera were detected through virome sequencing. Among them, Cucumovirus, Tobamovirus, and Potyvirus were the dominant genera, with abundances of 70.0260%, 12.4185%, and 0.3639%, respectively. The 9 plant viruses were cucumber mosaic virus (CMV), tobacco mosaic virus (TMV), tomato brown rugose fruit virus (ToBRFV), rehmannia mosaic virus (ReMV), potato virus Y (PVY), chilli veinal mottle virus (ChiVMV), tomato spotted wilt virus (TSWV), turnip yellows virus (TuYV), tomato yellow leaf curl virus (TYLCV). Metagenomic sequencing revealed a virus abundance of 0.3136%, with plant viruses accounting for 0.2861%, encompassing 39 species from 17 genera and 6 families. Among the DNA viruses previously reported in tobacco, tobacco vein clearing virus (TVCV), TYLCV and milk vetch dwarf virus (MDV) showed relatively high abundances, with 0.1264%, 0.0009%, and 0.0001%, respectively. Field surveys and PCR detections indicated that the dominant viruses in Qingdao tobacco were TMV, PVY, CMV. Secondary viruses included TSWV, ChiVMV, MDV, and TYLCV, with the first three being detected for the first time in Qingdao tobacco.