Study On The Inhibition Effect Of Plant Activator Protein To Tobacco Mosaic Virus And The Mechanism Involved

Plant virosis is one of important diseases of crops. The effectiveness and safety for disease control is far from demanding of agricultural production, so it is still very imperative to develop new type of antiviral agents. Plant activator is a kind of thermostable protein abstracted from fungi, which can promote plant growth, activate the guard system of plant and induce resistance, with the advantages of broad-spectrum, innoxious and environment-friendly. Preliminary research showed that the plant activator protein could control plant viral diseases efficiently.In this research, the control efficiency of plant activator protein in the system host (N. tabacum cv. Samsum) and lesion host (N. tabacum cv. Xanthi-NC) of TMV was evaluated by conventional biological and molecular biological methods, such as indirect ELISA, Western Blotting and semi-quantitative PCR. The results showed that plant activator protein could reach up to 67.27% for the protective effect and up to 66.73% for the therapeutic effect on system hosts; on detached leaves, lesion control rate of plant activator protein reached 40.23%, and it could inhibit lesions' extension with inhibition rate as high as 39.39%. In tobacco plants treated with plant activator protein, TMV coat protein in lesions decreased by 22.75%, in leaf diminished by 25%, and the content of RNA of TMV reduced by 28%.The experiments demonstrated that plant activator protein could induce defence substances in tobacco seedling, and its induction effect was similar to TMV. After treated with plant activator protein, the activities of SOD, POD, PAL a increased in tobacco leaves. Among which, the activity of SOD reached peak on the 4th day after treatment, increased 1.55 times compared with control group; and the activities of POD, PAL reached peak on the 13th day after plant activator protein treatment respectively, respectively which were 2 times and 1.78 times of untreated check.Taking Actin gene that is widely homeotic and highly conserved in eukaryote as the internal control, the expression difference of PR -5dB gene - a antivirus-related gene among N. tabacum cv. Xanthi-NC leaves with different treatments was mensurated by semi-quantitative RT-PCR method. It was found that the expression of PR ~5dB gene reached peak on the 5th day after plant activator protein treatment, approximately 5 times...