Study On Inhibition Efficiency And Relative Mechanisms Of Several Anti-viral Agents To Control Tobacco Mosaic Virus

It was studied by traditionally biological methods to test the efficiency of some ingredients including bio-chemicals, oligosaccharins and extracts from some Chinese medical materials to control tobacco mosaic virus (TMV) on Nicotiana tabacum'Havana 38". It indicated that a series of anti-viral agents such as extracts of Gallis Phois (GP), Oligosaccharins from Lentinula edodes (LE) and DM002 which was ingredient from a kind of medical plants were efficient to inhibit TMV on tobacco and GA looked most significant of three agents. After comparing with the ingredients origented from Gallis Phois (GP), it was found that Gallis Acid (GA) was a kind of most active ingredient on the inhibition to TMV. Then two models were set up to control TMV on tobacco in greenhouse. One was to spray 10%GP and inoculate TMV by hand onto upper leaves of tobacco two days later, the other was to spray a mixture (AB) and inoculate TMV by hand onto upper leaves of tobacco two days later, 7 days later sprayed again with 110μg/ml mixture which was made up of LE and DM002. It was also showed that the efficiency of two models were respectively 82.48% and 70.02% in greenhouse, and that of two anti-viral agents were 91.29% and 73.04% to control virus(TMV and CMV) in tomato fields which looked more remarkable than 20% Virus A WP ( 61.55%) which was traditional antiviral agent.The research was carried out on Oligosaccharins from Lentinula edodes (LE), DM002 and Gallic acid (GA) to inhibit the replication of tobacco mosaic virus. Firstly, it was proved by semi-quantitative RT-PCR that the anti-viral agents could decrease the amplification of virus nucleic acid (TMV-RNA) in vivo to some extent. Secondly, virus coat protein (TMV-CP) subunits were extracted by acetic acid method, and then mixed with the anti-viral agents to test absorbency for 320nm at the scope of 10℃～39℃. It was demonstrated that anti-viral agents could affect polymerization of TMV coat protein in vitro. Therefore it was concluded that GA could significantly inhibit TMV to normally replicate in vivo by TMV-RNA synthesizing, TMV-CP polymerization and the package of TMV-RNA and TMV-CP. In generally, the protective reaction of plant is resulted by some complicated metabolism and catalyzed by some bio-enzyme. Anti-viral agents such as LE, DM002 and GA spraying leaves of tobacco could induced alternative activities of Phenylalanineammonialyase (PAL), Peroxidase (POD), Endochitinase ,β-1,3-Glucanase and concentration of Hydroxyproline- richglycoprotein(HRGP) to resist to TMV. Therefore, it was demonstrated that GA was efficient to control virus and acted as elicitor to induce the resistance to plant virus.Pathogen related protein (PRs) was considered as one major mechanism to induce host to resist to pathogen and PR1-a gene was a special symbol for plant to induce systemic acquired resistance (SAR). PRs were detected by methods of PAGE-SDS and comparatively analyzed with the replication of TMV. It was found that PRs in plants which were sprayed GA and then inoculated by TMV two days later were not different from normal plants (Check), while other treatment with antiviral agents such as LE and DM002 were still same as plants only inoculated by TMV. PR1-a gene was amplified by methods of semi-polymerization RT-PCR. The results were showed that LE,DM002, GA and TMV could induce PR1-a gene to polymerize. It was remarkable that GA could induce PR1-a gene with high quantity for host to inhibit invasion of TMV. Therefore, GA was an elicitor to induce tobacco to resist to virus on the plant.