Reactive Oxygen Species And Phenylpropanoid Metabolism Involved In Induced Resistance Against Dry Rot Of Potato Tuber Treated With T-2 Toxin At Lower Concentration

Fusarium are important pathogens caused dry rot of patato tubers. T-2 toxin is a member of trichothecenes A, which are secondary metabolites produced by Fusarium. Howere, the induced resistance of T-2 toxin against dry rot in potato tubers and its mechanisms have not been reported. The efficacy of 1 μg/m L T-2 toxin treatment on the lesion diameter of potato tuber slices inoculated with F. sulphureum, the activity of key enzymes involved in reactive oxygen species and phenylpropanoid metabolism were investigated. The results showed that:1. Postharvest treatment with T-2 toxin at 1μg/m L T-2 significantly reduced the lesion diameter of potato tuber slices inoculated with F. sulphureum. The lesion diameter of treated tubers was 39.6% and 40.7% lower than that of the control after 6 day and 7days of inoculation.2 T-2 toxin treatments promoted oxidative burst occurs in tubers, especially in the early stage of treatment, O2.- production rate and H2O2 content increased. The content of MDA remaintained stable, indicating the stability of cell membrane was kept. The treatment enhanced the activity of NOX, CAT, SOD and POD. Therefore, the antioxidation ability of potato tuber was promoted. Meanwhile, higher antioxidant enzymes protected from damaging of host cells by excessive ROS.3. T-2 toxin treatment obviously enhanced the activity of APX, GR, MDHAR and DHAR. A higher activity of APX involved in declining of H2O2. Increasing of DHAR activity and decreasing of GR activity promoted the accumulation of As A and GSSG contents, reduced the content of DHA and GSH.4. T-2 toxin treatment significantly enhanced the activity of phenylalanine ammonialyase and 4-coumarate COA ligase, and promoted the accumulation of lignin, total phelic, flavonoid and anthocyanin, which increased resistance against diseases in potato tubers.In conclusion, postharvest treatment with T-2 toxin at a low concentrate significantly reduces the lesion diameter of potato tubers with inoculated with F. sulphureum bycausingoxidative burst, maintaining the stability of cell membrane, promoting the accumulation of products, increasing metabolism of active oxygen and phenylpropanoid metabolism in potato tubers.