青枯菌及其粗毒素对广藿香POD同工酶的影响

Objective: To study the pathogenic mechanism of Ralstonia solanacearum strain HX5 and its effects on the response of peroxidase(POD) isozymes in Pogostemon cablin. Methods: Ralstonia solanacearum strain HX5 used in this study was isolated from diseased Pogostemon cablin plants in our previous study. The pathogenicity of Ralstonia solanacearum strain HX5 to Pogostemon cablin was studied. The bacteria cell, bacteria fermentation filtrate (crude toxins) and bacteria fermenting liquid of strain HX5 were used to treat the test-tube plantlets of Pogostemon cablin, and the changes of the treated plantlets were observed. Polyacrylamide gel electrophoresis was used to analyze the bands changes of POD isozymes in control and treated plantlets. Results: The disease-infected index of the plants treated with bacteria fermenting liquid was 4.0, and the disease-infected index of the plantlets treated with crude toxins was nearly 4.0. The plantlets inoculated with bacteria cell basically stayed healthy. However, the disease occurred in the plantlets treated with crude toxins and bacteria fermenting liquid. POD isozyme electrophoresis analysis revealed the appearance of new POD isozyme bands in the spectra of treated samples compared to the untreated control. And there were common bands and specific bands among different treatments. Conclusion: Ralstonia solanacearum strain HX5 exhibits strong pathogenicity towards Pogostemon cablin, and bacterial exotoxins are the important virulence factor. POD isozymes might play a certain role in enhancing resistance of Pogostemon cablin against Ralstonia Solanacearum.?