Tobacco Etch Disease Investigation And Virus Detection In Hubei Province

Tobacco etch virus (TEV) is a linear-like virus in the genus Potyvirus and the virus family Potyviridae. The viruses are widely distributed in the world and have a broad host range. They can infect120dicotyledons species belonging to19different botanical families, especially to output of tobaccos which are often reduced caused by infection of TEV. At present, TEV infection has been found in Shanxi, Henan, Shandong and other provinces. In recent years, suspected etch disease commonly occurred in some tobacco-planting regions of Hubei province, however, it had never happened in Hubei before. In order to confirm pathogenic virus of the disease, we collected infected tobacco samples from different regions based on disease investigation to identify pathogeny with serological and molecular methods. The main results are as follows:(1) Incidence and damage of the disease:Results from investigation in Shiyan, Xiangyang, Yichang and Enshi during2011～2012showed that incidence of the disease differed among tobacco cultivars. Tobaccos with a common incidence of12.7%-17.3%, some with high incidence of22.9%-27.2%while others with low incidence of3.6%～4.3%. Infected leaves had densely-distributed chlorotic spots and etched symptoms, some seriously infected were even perforated and withered up.(2) Detection of histological sections:Ultrathin sections made from typical infected samples were observed under transmission electron-microscope. We found that pinwheel inclusions and filoviruses were existed in infected tissue cells.(3) Result of serology detection:DAS-ELISA results of383samples collected from different regions of Hubei province showed that TEV prevalence of tobaccos in Shiyan, Xiangyang, Yichang and Enshi were51.1%,51.4%,29.4%,5.0%respectively. In addition, the infection differed from tobacco cultivars. The TEV detection rates in flue-cured tobacco, burley tobacco and Maryland tobacco were39.2%,21.6%,21.1%respectively.(4) Result of situation detection:a size of789bp specific target band of TEV was obtained after the RT-PCR using the specific primers,which is the same as that mentioned in a previous relevant report.According to field surveys and laboratory tests, we can preliminary confirm the damage of TEV in Hubei province. Our present research only includes conventional identification of TEV, further studies should be conducted to explore its pathogenetic regularity and prevention methods.