Preliminary Study On Seed-borne Transmission Of Tobacco Mosaic Virus In Tobacco

Tobacco mosaic virus (TMV) is one of the main tobacco diseases in the world, it can reduce tobacco yield to 30-50%, causing great economic losses. Seed-borne transmission of TMV can cause TMV to spread easily and induce disease epidemic when the expansion floating system is used. Seed-borne transmission of TMV in tobacco and methods for removing the virus tobacco seed were studied in this paper.Triple sandwich ELISA (TAS-ELISA) was used to detect TMV in tobacco seed. TMV was detected in seeds of five tobacco cultivars by TAS-ELISA. TAS-ELISA can sensitively detect TMV in seeds, and 100% infections in seeds were found when 3 seeds were used for detection. Growing tests show that seed-borne transmission of TMV has some effect on seed germination. Moreover, detections of the virus in seed coat, bud and seedlings of various tobacco species showed that TMV infect seed coat in tobacco seed.Using healthy seeds of tobacco cultivars K326, Yunyan85 and Yunyan87, a potted experiment was conducted to detect the percentage of tobacco seed containing TMV after mechanical inoculation with TMV at rosette stage, fast growing stage and flower-bud appearing stage. Detection results showed that the proportion of tobacco seeds containing TMV varied in different inoculated stages and seeds from seedlings inoculated at the fast growing stage had the highest percentage of TMV infection. Detections of virus content in calyx, corolla, ovary, stamen and pistil of K326 inoculated with TMV at different stages indicated that corolla had highest virus content among these tissues, and virus content in these tissues in tobacco plants inoculated with TMV at fast growing stage was higher than those inoculated at rosette or flower-bud appearing stages. Evaluation of 7 kinds of chemicals (10% Na3PO4, 0.1% KMnO4, 0.1%CuSO4, 1:400 kang-du-feng, 1:600 du-xiao, 5% washing powder and water) for removing seeds of K326 tobacco revealed that 10% Na3PO4 treatment had remarkable effect for controlling seed-borne transmission of TMV.