Molecular Identification Of Tobacco Virus Diseases In Guangxi Province

Virus diseases are important diseases in tobacco production. In order to develop effective prevention and control measures for tobacco virus diseases, we conducted a survey of the occurrence of tobacco virus diseases in Guangxi Zhuang Autonomous Region. Based on symptoms, the virus diseases of tobacco were divided into mosaic virus disease, necrosis-like virus disease, tobacco leaf curl disease. The collected samples were identified by ELISA, PCR, RT-PCR and small RNA sequencing and six kinds of virus were identified including Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), TVBMV, Potato virus Y (PVY), Tomato zonate spot virus (TZSV) and Tobacco leaf curl virus (TLCV). Tobacco vein bandingmosaic virus (TVBMV) was identified first in Guangxi tobacco. TMV, CMV, TVBMV were detected in mosaic virus disease and TWV got the highest relevance ratio which was58.7%. The following relevance ratio is9.8%from CMV. One sample was mixedly infected by TMV and CMV. Meanwhile another sample was mixedly infected by TMV and TVBMV. In necrosis-like virus disease, the relevance ratio of PVY was4.3%. TZSV was detected only in one sample from Jingxi County and TYLCV was detected from samples of tobacco leaf curl diseases which were collected in Tianlin County Tobacco Board.CP genes of TMV, CMV, PVY were sequenced and analyzed. There were27base differences in CP genes of seven TMV isolates. There was only one different amino acid residue in the amino acid sequence of BS-3and HZ-1compared with other amino acid sequences. There were two different amino acid residue in the amino acid sequence of HZ-2compared with other amino acid sequences. The BLAST results of TMV CP sequences in NCBI database showed that CP genes of BS-1, HZ-3had the highest similarity of99.6%compared with that of Yunan isolate. CP genes of BS-2, BS-3and HZ-1had the highest similarity of98.1%compared with that of Fujian isolate. CP genes of HC-1and HC-2had the highest similarity of99.6%compared with that of Shanxi isolate. We used the sequence of CMV HZ isolate and known sequences to constructed a phylogenetic tree which indicated CMV HZ isolate belonged to CMV subgroup I. The CP gene of PVY HZ isolate was comparised with PVY CP gene and a phylogenetic tree was constructed which indicated the CP gene of PVY HZ isolate belonged to O strain group.