Correlation Between Defense Enzymes in Tobacco and Induce Systemic Resistance(ISR) to TMV Induced by VA

VA,a natured anti virus agent from several kinds of plants,was used as an elicitor.On the seventh day after treatment with VA,the newly developed leaf of Nicotiana tabacum L.SamSun NN and SamSun was inoculated with TMV.It was showed that ISR in Nicotiana tabacum L.against TMV was induced by VA.Local lesion inhibition rate was 64 3%,lical lesion diameter inhibition rate was 37 3%.Superoxide dismutase (SOD) and Peroxidase(POD) activities in the newly developed leaf of Nicotiana tabacum L.increased significantly after treatment with VA.The increase rates of the two enzyme activities were the greatest at 48 h after inoculation with TMV.However,the content of MDA reduced after treatment with VA.The results suggest that ISR in tobacco against TMV were induced by VA and TMV together.